EPA-R2-73-153
January 1973
Environmental Protection Technology

The Determination  of Mercury
in  Stack Gases of High SC>2
Content by the Gold
Amalgamation Technique
                             Office of Research and Monitoring
                             U.S. Environmental Protection Agency
                             Washington, D.C. 20460

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                                            EPA-R2-73-153
    The Determination of  Mercury

in Stack Gases of High  SC>2 Content
                   by  the Gold
        Amalgamation  Technique
                           by

               Charles Baldeck and G. William Kalb


                      . TraDet,  Inc.
                      P.O. Box  5093
                     930 Kinnear Road
                    Columbus, Ohio  43212


                    Contract No.  68-02-0697
                  Program Element No. 1H1326
               Project Officer:  Howard L. Crist

        Quality Assurance and Environmental Monitoring Laboratory
             National Environmental Research Center
            Research Triangle Park, North Carolina 27711
                       Prepared for

               OFFICE OF RESEARCH AND M3NITORING
              U.S. ENVIRONMENTAL PROTECTION AGENCY
                  WASHINGTON, D.C.  20460

                       January 1973

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This report has been reviewed by the Environmental Protection Agency



and approved for publication.  Approval does not signify that the



contents necessarily reflect the views and policies of the Agency,



nor does mention of trade names or commercial products constitute



endorsement or recommendation for use.
                                    11

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                            ABSTRACT








Elemental mercury, present in the reducing atmosphere of exhaust flue




gases from a zinc smelter may be quantitatively determined by the gold



amalgamation technique.  This method avoids interferences by strongly



reducing substances, such as SO , encountered in the direct application



of the normally used wet oxidation techniques (e.g., IC1 or KMnO,




scrubbers) to these sources.  The gas sample may be taken isokinetically




using a standard isokinetic stack sampling apparatus in which some of the




impingers are replaced by a series of amalgamators, each containing 30




grams of gold chips.  After sampling, these amalgamators are removed from




the sampling unit and the trapped mercury is fired by an induction



furnace into a nitrogen stream which carries the revolatilized mercury




into a solution of 3% KMnO,  in 10$ HWO , where it is oxidized and




retained.  The resulting solution is then analyzed for mercury by




reduction with hydroxylamine hydrochloride and stannous chloride




followed by direct aeration through a "mercury vapor monitor" which




measures the absorbance at 2^3.7 nm.  Mercury collected with the part-



iculate portion of the sample may be determined by nitric acid diges-




tion of the filter followed by reduction with stannous chloride and




aeration.






Several combinations of impingers and amalgamators were investigated




to determine the optimum train configuration.  Collection efficiency



of the optimized train was found to approach 98-100£ and to be indepen-




dent of the sampling rate in the range 0.3 to 0.8 CM.  Equations were
                                 iii

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derived for estimating the collection efficiency of the train from




the relative distribution of mercury found on successive amalgama-




tors.  The most crucial parameter affecting the collection efficiency



was found to be the cleanness of the gold used.  Sources of error and



possible gold contamination are discussed.  Analytical procedures for




determining the mercury concentration were studied, including (1) KMnOi




and IC1 as oxidizing solutions, (2) direct aeration and reamalgamation,




(3) air and nitrogen as tne carrier gases, (h) the use of magnesium



perchlorate as a drying reagent, (5) the use of mixing chambers, and (6)




the utilization of a mercury vapor monitor as compared to a modified




atomic absorption spectrophotometer.  The recommended procedure for the



determination of mercury in a stack gas using the method optimized in this



study is presented in the appendix.
                                IV

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                         TABLE OF CONTENTS
INTRODUCTION                                                  1

LABORATORY INVESTIGATIONS                                     ^

        1 - Introduction
        2 - Instrumental Methods
        3 - Oxidizing Solutions
                 a - KMnO^
                 b - Id
        U - Water Background
        £ - Carrier Gases
        6 - Direct Aeration
        7 - Amalgamation
        8 - Recommended Analytical Procedure
        9 - Mercury Capacity of the Gold
        10- Filter Analysis

FIELD INVESTIGATIONS                                         33

        1 - The Sampling Site
        2 - Sampling Equipment
        3 - Field Sampling Procedure
        k - Laboratory Analytical Procedure

RESULTS AND DISCUSSION                                       US

        1 - The Data Table
        2 - Sampling Train Configuration
        3 - Initial Scrubber Solution
        U - The Use of KMnOi  Solutions
        5 - Critical Parameters
        6 - Collection Efficiency of the Amalgamators
                 a - Theory
                 b - 20 grams of Gold per Amalgamator
                 c - 30 grams of Gold per Amalgamator
        7 - Sources of Error
                 a - Sampling Errors
                 b - Analytical i Errors
        8 - Application to Isokinetic Sampling

CONCLUSIONS                                                  73

APPENDIX I  Data Table                                       77

APPENDIX II  Recommended Procedure                           99

APPENDIX in  Isokinetic Data Sheet, Run 72                108

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                           LIST OF FIGURES
Figure

  1.  Relative Response of the IDC Mercury Monitor and
      an Atomic Absorption Spectrophotometer with a
      $g Inch Quartz Optical Cell using the Direct
      Aeration Technique.                                       7

  2.  Relative Response of the LOG Mercury Monitor  and
      an Atomic Absorption Spectrophotometer with a
      $g Inch Quartz Optical Cell using the Amalgamation
      Technique.                                                8

  3»  Effect of Mixing Chambers on Analytical Curves with
      the Direct Aeration Procedure.                            10

  I;.  Effect of Mixing Chambers on Analytical Curves with
      Amalgamation.                                             11

  £.  Analytical Curves obtained from Direct Aeration  of
      IC1 Standard Solutions.                                   19

  6.  Effect of Magnesium Perchlorate on Water Absorption
      under High Humidity Conditions.                           21

  7»  Analytical Curves obtained by Direct Aeration illustrat-
      ing the Effect of Water on Magnesium Perchlorate
      Deterioration.                                            23

  8.  Water Absorption at 2$U nm as a Function of Water
      Temperature.                                              25

  9.  Analytical Curves obtained by Direct Aeration utilizing
      Magnesium Perchlorate with KMinD^ and ^0 Standard  Solutions
      and Nitrogen and Air as the Carrier  Gases.                 26

  10. Analytical Curves obtained by Direct Aeration of KMnO> ,
      IC1 and H20 Standard Solutions.                      u    27
  11. Analytical Curves obtained from KMnOj. and HpO Standard
      Mercury Solutions by Amalgamation.                         29

  12. Mercury Collection Efficiency of Gold Amalgamators:
      Mercury Bypass as a Function of the Quantity of Gold.       31

  13. Flow Chart of the Initial Smelting Process at the
      ASARCO Columbus, Ohio Zinc Smelter.                        3U
                                 vi

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1U.  Illustration of the 15 mm Amalgamator.                35

1$»  Apparatus used for Firing the Amalgamators.           ^3

16.  Collection Efficiency vs. Sampling Rate  for 20        (^
     Grams of Gold per Amalgamator.

17.  Collection Efficiency vs. Total Mercury  Collected     (£
     for 20 Grams of Gold per Amalgamator.

18.  Collection Efficiency vs. Sampling Rate  for 30        Qg
     Grams of Gold per Amalgamator.

19.  Collection Efficiency vs. Total Mercury  Collected     ^
     for 30 Grams of Gold per Amalgamator.

20.  Configuration of the Recommended Sampling Train.      103

21.  Data Form                                            108
                            vii

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                    LIST OF TABLES
Table

 1.  Half-Reactions Involved in the Oxidation-
     Reduction of Mercury.                                  lU

 2.  Sampling Train Configuration.                          i;7

 3.  Distilled Water as the Scrubber.                       1*8

 U.  Stannous Chloride as the Scrubber.                     i#

 5.  The Effect of Firing the Amalgamators in the
     Presence of the Quartz Wool Plug                       55

 6.  Collection Efficiencies                                58

 7.  Theoretical Distribution of Mercury in a Series
     of Amalgamators.      '                                 59

 8.  Maximum Escape Fraction for 95$ Recovery.              62
                            viii

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INTRODUCTION


The discovery of unacceptable levels of mercury in water and certain

foods has led to an increased concern over the possible pollution of

the environment with mercury.  The persistence of mercury and its

tendency to accumulate in some parts of the ecological system are im-

portant aspects of the problem.  These developments have stimulated

interest in the analytical techniques for mercury and numerous improved

methods have been published for its determination in foodstuffs, animal

tissues, blood, urine, water, geological samples, sedimoit, pulp, soil

and rocks.  For many of these applications the flameless atomic absorp-

tion method (often combined with an amalgamation step to improve

selectivity and sensitivity-'-) has been found faster, less cumbersome

and more sensitive than the classical dithizone extraction method.


Although the U.S. Government has established maximum permissible levels

for mercury in various foodstuffs and for plant effluent to streams,

little data is available on the quantity of airborne mercury emitted

from such sources as coal-fired power plants or smelting operations.

Most coal has been shown to contain 0.0$ to 0.50 ppm mercury   and a

cross section of copper, zinc, and lead sulfide ores from the United
          .W. Kalb, The Determination of Mercury in Water and Sediment
Samples by Flameless Atomic Absorption, Atomic Absorption Newsletter
9(U), PP. 81-37(1970).

        ^Personal Communication, ASTM Committee D£,21, Trace Element
Task Group.

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States has been analyzed for mercury showing a range of  0.0£ to

300 ppm.   This naturally occurring mercury is volatilized during

combustion and could result in the release of a significant quantity

of mercury into the atmosphere.


The two methods ordinarily used for the determination of mercury in

air are subject to massive interferences from the other components

normally found in stack gases, particularly SO .  Efforts to determine

the mercury in stack gases by drawing the gas through a sampling train

containing a liquid oxidizing agent (acidic KMnO^ or IC1) have not been

successful.  The high S02 concentration in the sample reduces the

oxidizer almost immediately, eliminating its ability to oxidize the

mercury to the mercuric state.  The direct measurement of mercury in

air using a "mercury vapor monitor" is another widely used technique.

The air sample is drawn between an ultraviolet source which emits the

2$3.7 nm mercury vapor resonance line and a photocell detector.  The

absorbance is measured and can be converted directly to mercury con-

centration; but the response is not specific since SO , most organic

substances, smokes, and aerosols also absorb at this wavelength.  An

alternate method of mercury collection is needed for stack sampling;

one which does not depend on the oxidation of mercury for entrapment.

Such a method would enable longer sampling times to be used, even in
         ^Personal Communication, David Patrick, Environmental Protection
Agency, Research Triangle Park, North Carolina.

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the presence of high SO  concentrations.  Previous work by the authors

has shown that elemental mercury can be quantitatively collected from a

stack gas sample by direct amalgamation onto gold.  The mercury can then

be revolatilized by heating and determined by any of several methods.  Good

recovery of mercury was obtained from the effluent gas of a coal-fired

power plant and a zinc roaster where SO- concentrations averaged around

7-8$.  Although recovery of mercury in this earlier work was generally good,

the analytical method used (firing the gold in an air stream which carried

the revolatilized mercury through a quartz cell positioned in the beam of

an atomic absorption spectrophotometer) was too sensitive, limiting the

feasible sampling time to 1-3 minutes, depending on the mercury concentra-

tion, and subject to interferences from any moisture, sulfuric acid mist or

other substances which condensed on the gold during sampling.  These problems

limited the accuracy and reproducibility of the results obtained.  The

present work was undertaken to solve these problems and generally improve

the practicality of the gold amalgamation method as applied to stack

sampling.  The goal of this work was threefold:

         1.  To develop a procedure which would allow a sampling time of
             at least 15 minutes at isokinetic rates (i.e., a sampling rate
             of 0.5 - 0.8 CFM, or under actual isokinetic conditions).

         2.  To obtain and show a collection efficiency of at least 9$%
             for the mercury.

         3.  To perfect the method of firing the gold into an acidic
             KMnOi  solution with subsequent analysis of aliquots of this
             solution by flameless atomic absorption.

These goals were successfully attained in this study.
         ^G.W. Kalb and C. Baldeck, The Development of the Gold Amalgamation
Sampling and Analytical Procedure for Investigation of Mercury in Stack
Oases, Environmental Protection Agency Contract No. 68-02-03l4l (1972).

         %.W. Kalb, The Adaptation of the Gold Amalgamation Sampling and
Analytical Procedure for Investigation of Mercury in Stack Gases to High S02
Environments Observed in Smelters, Environmental Protection Agency Contract
No. 68-02-03U1 (1972).

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LABORATORY INVESTIGATIONS






1 - Introduction






A previous study has shown that volatile mercury in smelter gases may




be quantitatively collected on gold by an amalgamation reaction.  (At




the high temperatures (500°F) and the reducing atmospheres observed in




smelter gases the mercury present will be in the elemental state.)  The



mercury was analyzed by firing the amalgam in an induction furnace and



then monitoring the volatile mercury concentration by flameless atomic




absorption*  Standards were run after each sample to calibrate the




instrument.  Although the smelter investigated used an ore of relatively




low mercury concentration, the mercury concentration was sufficiently




high to limit the sampling time to one minute.  Samples collected iso-




kinetically for longer periods of time contained more mercury than could



be analyzed by the system.






In order to obtain a representative sample a longer sampling period was




required resulting in the otherwise arbitrary choice of a desired




15-minute sampling period.  Sample splitting procedures and redesign




of the optical system could not adequately desensitize the system,




especially when it is realized that ores used in some smelters contain



300 times the mercury concentration observed in the smelter studied*



As a result of this it was decided to revolatilize the mercury collected



on the amalgam, absorbing the revolatilized mercury in an acidic perman-




ganate or iodine monochloride solution.  Aliquots of these solutions




could then be diluted for analysis.  It was the objective of this phase




of the contract to study various methods for analyzing these solutions.

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The mercury-gold amalgam obtained from sampling the stack gas is fired

in a resistance or an induction furnace with a compressed gas stream

carrying the mercury through a liquid absorption cell containing an

iodine monochloride or acidic permanganate solution that quantitatively

removes the mercury from the gas stream.  An aliquot of this solution

is then diluted to a satisfactory range for analysis.  Procedures in-

vestigated for the analyses of these solutions included: (1) direct

aeration of the reduced KMnOi  or IC1 solution into a flameless atomic

absorption spectrophotometer, and (2) secondary amalgamation accom-

panied by the direct firing of the amalgam into a flameless atomic

absorption spectrophotometer.  These procedures were studied using

both air and nitrogen as the carrier gases and with and without magnes-

ium perchlorate as a drying reagent in the gas stream.  Various mixing

chambers were also investigated as an additional means of desensitizing

the analytical method.


The second objective of this study was to determine the ultimate cap-

acity of the gold for mercury.  The results from this are to be used to

determine the size and shape of the final amalgamator to be used in

conjunction with the isokinetic sampler in obtaining the sample from
                                 i
the stack.


The final objective of the laboratory study was to develop a method

for analyzing the filters containing the participates collected during

sampling.

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 2- Instrumental Methods






 The instrumental methods were investigated by comparing their sensitivity




 and response with standard mercury in water solutions.  $0 ml aliquots




 of the various mercury standards were reduced with 2 ml of a solution




 of 20$ SnCl  in 50£ HCl.  These standards were then aerated, quickly




 volatilizing the reduced mercury.  The air stream carried the mercury




 either directly into a quartz optical cell located in the path of an




 atomic absorption spectrophotometer operated at 25U nm (direct aeration)




 or onto gold (secondary amalgamation).  In the latter use, the gold




 amalgamator was then fired in an induction furnace revolatilizing the




 mercury which was carried by the air stream into the optical path of



 the spectrophotometer.  A model 303 Parkin-Elmer atomic absorption




 spectrophotometer and a Laboratory Data Control (IDC) Mercury Monitor




were utilized for the study.






Figure 1 shows the relative response of the LOG Mercury Monitor witn




 a 30 cm path lengtn and the atomic absorption spectrophotometer with




 a 6-^5 incn optical cell, using the direct aeration technique.  The two




units were operated at the same air flow (l.U liters/minute).  The




IDC unit, operated at a 0.614. range (least sensitive available),




 shows an absorbance of 80 with a 1 tig mercury standard.  The atomic




absorption unit has a considerably lower sensitivity.  Figure 2




illustrates a similar comparison, but with the secondary amalgamation




metnod.  The gold amalgams were fired at different temperatures (%




variac setting) in the induction furnace.  The secondary amalgamation

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   6O-
Figure 1. Relative Response of  the IDC Mercury Monitor and an Atomic Absorption
          Spectrophotometer with  a &$ Inch Quartz Optical Cell using the Direct
          Aeration Technique.

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Figure 2.  Relative Response of the IDC Mercury Monitor  and an Atomic Absorption
           Spectrophotometer with a 62g Inch Quartz Optical Cell using the
           Amalgamation Technique*

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procedure, originally designed to eliminate interferences and increase




sensitivity, is considerably more sensitive than the direct aeration




method.






The LDC unit is, as would be expected, more sensitive than the atomic




absorption spectrophotometer.  The LDC unit in conjunction with amal-




gamation approaches the maximum limit of sensitivity.  At the low




mercury concentrations required to remain on scale there is considerable




fluctuation in the absorbance values.  The sensitivity of this method




is such that it is useful only under optimum conditions.  This appears




to be because of temperature fluctuations in the optical cell due to




the firing of the amalgam, resulting in an unstable equilibrium between




the volatile materials and the cell walls.  This, in conjunction with




the high sensitivity due to the long cell, severely limits its usage.






Figures 3 and k illustrate the effect of mixing chambers on the sensi-




tivity of the direct aeration and secondary amalgamation procedures.




The two mixing chambers investigated, l£0 ml and 270 ml gas collection




tubes, did not significantly decrease the sensitivity with either the




direct aeration or amalgamation techniques.  They did improve the repro-




ducibility of the peaks by decreasing the sharpness of the peak tip with




both procedures.  It is likely that utilizing the mixing chambers




with the secondary amalgamation procedure will decrease the sudden




thermal expansion of the gas, which could be responsible for the lack




of reproducibility with the highly sensitive LDC Mercury Monitor.

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                                                                     10
  Absorbance
80-
 40-
no mixing chamber


         150ml



         27Oml
Figure 3*  Effect of Mixing Chambers on Analytical Curves with the Direct
          Aeration Procedure.

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SO-
                                                              rng  Hg
  Figure 1*.  Effect of Mixing Chambers on Analytical Curves with Amalgamation.

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                                                                    12
The results of the instrumental analysis comparison has suggested that




the secondary amalgamation procedure is unnecessary.  The amalgamation




procedure is designed to eliminate interferences and increase sensitivity.




The primary amalgamation step utilized in the original collection of the




stack gas sample and the desire to decrease the sensitivity, limits its




usefulness unless an interference is found in the oxidizing solutions.



The amalgamation procedure can be partially desensitized by lowering




the firing temperature or the air flow rate.  If the amalgamation pro-




cedure is adopted, it is recommended that the mixing cells should be




used in conjunction with the 6-^g inch optical cell in the atomic




absorption spectrophotometer.  If the IDC Mercury Monitor is to be used,




a shorter optical cell would be advantageous ($500.00).  Considering the




high mercury concentrations of the oxidizing solutions to be analyzed,



the direct aeration procedure, utilizing either the LDC Monitor or the




Perkin-Elmer atomic absorption spectrophotometer is recommended.  With




this procedure mixing chambers would not be required.






3- Oxidizing Solutions






The oxidizing solutions to be utilized in collecting the mercury at the




field site are to be a 3% KMnOi  solution in 1.0% concentrated nitric



acid or a 0.1 N IC1 solution.  In practice these solutions would be




diluted for final analyses.  Due to the various dilutions that will be




performed on the actual samples and as a check on any possible inter-




ferences, the laboratory study was performed with the above strength




solutions.  These solutions were then spiked with known amounts of

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                                                                    13



mercury before analyses.  Analysis of mercury in water standards have


been thoroughly investigated by this laboratory and were utilized for


comparison with the oxidizing solutions, as well as to compare the


various instrumental procedures.
a.


The reactions responsible for the oxidation and reduction of mercury


in the permanganate system are shown in Table 1,  In acidic solutions


the permanganate ion is a strong oxidizing reagent.  The half reaction


is



         MnOr  +  8H+  +  5e~ * - -  Mn++  +  ltf_0         E°  =  1.51
            U                     7             2



This half reaction only occurs in strongly acidic solutions (0.1 N or


greater) .  In less acidic permanganate solutions




         Mrfl"  +  l|H*  +  3e" '    , Mifl2  +  21^0         E°  -  1.695




In alkaline solutions
         MnO~  +  2H00  +  3e~ -—7 MnD.  +  UOH*         E°
In strongly alkaline solutions



         Mrf)~  +  e"         ^   ,   MnO"                  E°
            k                           h


Permanganate is unstable in the presence of Mn  , but the reaction is


very slow in acidic media
         2MnO   +  3Mn    +  2H 0
             k                 2

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                                                                   Ill
                           TABLE 1


   Half-Reactions Involved in the Oxidation-Reduction of Mercury


                                                              Potential
1.  Oxidation of Mercury:


                 Hg°             ±^   Hg4


         (Strong Acid)
                                                  2e'
                       -0.852
         (Weak Acid)
                       +  2H20
2. Reduction of Excess Mn07 :
                          k

         (Strong Acid)
                 Mn    +  liH 0
         (Weak Acid)
                 MnO,
                       +  2H20
                 Mn    +  2H 0
                            2
                 HgNOH'HCl
3«  Reduction of Mercury:


                   °
                 Hg


                 Sn*"*"  +   6C1~


                 NO,   +   2H00
                  2 h       2

                 HNO«  +   UH 0
                    ^       2

                 N02   +   2H20
MnOr  +  8H+
                                                          ~   -1.51
                 3e~   -1.695
                                      MnO~
                                          U
         8H*
MnO-  +  UH*  +  3e-   -1.695
   u

         i4H+  +  2e~   -1.23
                                       MrtD
(N0, N0, HN02)
Hg++  +  2e~


SnCl. +  2e~
    6

2NO-  +  UH*
   3

NO"   +  3H*


NO"   +  UK*
                                                              -0.852


                                                              -0.15


                                                     +  2e-   -0.9


                                                     +  2e-   -C.9U


                                                     +  3e~   -0.96
          H.A. Laitinen, "Chemical Analysis," McGraw-Hill Book Company,

New York, N.T., I960.

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This reaction would affect the length of storage of KMnOr solutions




after the mercury has been collected.  The overall reaction would be
      5Hg°  +  2MnOj  +  16H+   *	   £Hg++  +  2Mn++  +  8H20






The Mn   would eventually lead  to the deterioration of the permanganate.
     catalyzes the decomposition of permanganate under acidic conditions




resulting in the necessity of filtering fresh permanganate solutions.



Any organic material,, present in the storage vessel will reduce the




permanganate to MnO^ resulting in autodecomposition.  Acidic and alka-




line solutions of permanganate are less stable than neutral solutions.




MnD2 will also form in the initial oxidation of the volatile mercury if




the solution is not sufficiently acidic (see Table 1).






With the utilization of the permanganate system the excess permanganate




(that not required to oxidize the mercury) is reduced with hydroxylamine




hydrochloride,  The half reactions are shown in Section 2 of Table 1,




(The oxidation potential of the hydroxylamine hydrochloride is unknown,




but would be between 0.9 and 1.23 volts.)  The formation of Mn + or
     is dependent upon the acidity of the solution.  It should be noted



that the by-products from the oxidation of the hydroxylamine hydro-



chloride are volatile NOX compounds.





The final revolatilization of the mercury is accomplished by reducing



the mercury with a stannous chloride solution.  The half reactions are



shown in Section 3 of Table 1.  The stannous chloride will also reduce



the nitric acid (used to acidify the permanganate) forming volatile



NO  compounds.

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                                                                     16




In this study 3$ w/v aqueous permanganate solutions were prepared from



reagent grade potassium permanganate and were filtered to remove any



   o present in the original crystalline material.  Acidic solutions



    ml) were then prepared by adding concentrated nitric acid to achieve



a 10/5 nitric acid concentration.  Known concentrations of mercury in



water (slightly acidified) were then added to these prior to analysis.



A 10J6 hydroxylamine hydrochloride solution (5 ml) was used to reduce



the excess permanganate and a 20% SnCl2 in 5Q£ HC1 (3 ml) was used to



reduce the bivalent mercury to elemental mercury.  These solutions



were then aerated, either directly through the spectrophotometer or



amalgamated onto gold.





The acidification and reduction of the excess permanganate are both



exothermic reactions.  Optimization of the addition of the reducing



agents showed that more SnCl  was required with the permanganate than



with a mercury-water standard, even when the excess permanganate has



been completely reduced.  The results showed that 3 ml of the SnCl2



solution was required compared to one ml with a similar mercury-water



standard sample.  (Additional hydroxylamine hydrochloride had no effect



on the stannous chloride requirements.)  This probably represents the



reduction of the nitric acid which has a slightly higher oxidation



potential than the elemental mercury (Table 1) .  NOX compounds are



released during both reduction steps.  The final reduction of the mer-



cury occurs in a closed system resulting in the inclusion of the



volatile NO  compounds in the sensing cell with the volatilized mercury,
           jC


unless gold amalgamation (secondary amalgamation) is utilized.  Several

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                                                                    17





investigators have suggested that NO  compounds interfere with the



analysis.  Although some questionable results have been obtained, NO.,



has not been correlated to problems with either the direct aeration



or amalgamation procedures.






The reduced permanganate standards produced higher peaks than observed



with water standards.  The higher peaks are a result of the blank mercury



concentration in the permanganate as well as a slightly quicker release



of the mercury from the solution probably due to the excess stannous



chloride.






Initial studies showed an increase in sensitivity with the age of the




acidified permanganate.  Approximately 3 hours was required after



acidification before maximum sensitivity was obtained.  More recent



studies with both the 10JK and 25? acidified permanganate samples showed




no differences in sensitivities between samples stored for 15 minutes or



3 hours before analysis.  Both series were performed by identical pro-




cedures and no explanations are offered for the observed differences.






Mn02 is sometimes formed during the reduction of the excess permanganate.



The brown precipitate disappears with additional stirring of the sample.



The occurrence of the MnD  has not been correlated to any procedural



differences and no analytical differences have been observed because of




it.  Mr. Joseph DeGarmo of American Electric Power has correlated this




with deterioration of the magnesium perchlorate leading to absorption




of the volatile mercury by the perchlorate.
         "Personal Communication.

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                                                                      16
The stability of the spiked permanganate solutions reduced with

hydroxylamine hydrochloride was investigated.  Permanganate solutions

spiked with 0.25> and O.£0 ug mercury were reduced with hydroxylamine

hydrochloride and then stored for 10 rain., 30 min., 1 hour, h hours,

and 22 hours before final reduction and analysis.  No significant

differences were observed between the various intervals.  It is the

opinion of the authors that since the HIJO-, is not reduced by the

hydroxylamine hydrochloride there should not be a significant loss of

mercury with storage.  This is in contrast to the results reported by

Mr. S.T. Hirozawa of the Wyandotte Chemicals Corporation.'


Although some problems have occurred with permanganate solutions, the

authors feel that when collecting inorganic mercury, accurate, reliable

data can be obtained from permanganate solutions utilizing either direct

aeration or amalgamation.  The purpose of the oxidizing solutions in the

stack sampling procedure is to split or dilute the sample.  This will

decrease any peculiar effects of the solution.


b. IC1

The IC1 method utilized in this study was the Determination of Mercury

in Particulate and Gaseous Emissions from Stationary Sources developed
       /Q\
by EPA.     The results obtained from this procedure are presented in
        7
          S.T. Hirozawa and J.K. Rottschafer, "Trip Report - Mercury
Emission Via Hydrogen Gas and Fume Headers at Port Edwards," memo to
C.V. Francis, 1/15/71.

       8 Federal Register 36(234), Dec. 7, 1971.

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                                                                       19
  Absorbance
60-
                                        a N2-Mg(CIO4)2

                                        •  N2-No Mg(CI04)2


                                        O Air- Mg(CIO4)2


                                        •  Air-No Mg
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                                                                      20




Figure 5-  The technique is extremely sensitive to any procedural




variations and the presence of any water or water vapor in the system.




This resulted in extensive practice being required for each technician




involved in the study.  Even with experienced personnel different indi-




viduals could not obtain acceptable agreement in results.  Because of




this, the utilisation of this procedure for routine analyses is ques-




tioned by the authors.






li- Water Background






Water vapor will absorb 2^U nn radiation resulting in erroneous peak




heights when determining mercury concentrations.  This interference is




dependent upon the relative humidity r;p_:i nay be eliminated by utiliza-




tion of the gold amalgamation technique or a desicant, such as magnesium




perchlorate, between the aeration cell and the optical cell.  The amal-




gamation procedure separates the water vapor and the mercury by collecting




the mercury on the gold and passing the water vapor.  With the direct




aeration procedure the water vapor is eliminated by absorption onto




magnesium porchlorate.






Figure 6 illustrates the effect of utilizing magnesium perchlorate with




the direct aeration technique under high humidity conditions.  These




results were obtained under high humidity conditions using nitrogen as




the carrier gas.  Under dry humidity conditions, essentially no back-




ground water vapor is observed when using the direct aeration technique.




Extensive analyses of these parameters has shown that a high background




water vapor value is obtained under high humidity, even when the air or

-------
 o
 u
 c
 o
JO
 I
                                                           Water Background
                                                           N2  Flow  3
                                                           No Mg(CIO4)2
                                                           O.5 H9 Hg
                                                           Direct Aeration
                                                             H2O blank  no

                                                             O.5 jjg Hg no Mg(CIO4)2
                                                             O.5 pg Hg Mg(CIO4)2
                                    Time
Figure 6.  Effect of Magnesium Perchlorate on Water Absorption under High Humidity Conditions.

-------
                                                                 22




nitrogen used as the carrier gas is dried before the aeration cell.



Since the air in the dead space above the liquid phase in the aeration




cell is quickly purged with the carrier gas, it is concluded that high



humidity conditions have a chemical effect on the liquid sample result-




ing in the vaporization of more water under these circumstances.






With the introduction of magnesium perchlorate as a desiccant between




the aeration cell and the optical cell this background is eliminated




(see Figure 6).  Magnesium perchlorate has been observed by the authors



and reported by other investigators to undergo deterioration and even-




tually absorb the volatile mercury.  To determine the effect of this



deterioration in order to know when the magnesium perchlorate should be




replaced, water was added dropwise to the magnesium perchlorate and




standard analytical curves were obtained.  The results of this study are




shown in Figure ?•  There were no significant losses of mercury observed.




Additional water was added until it had completely saturated the magnes-




ium perchlorate.  There was no loss of mercury until the tubing below




the desiccant became clogged with the saturated suspension.  Temperature




effects have been observed to deteriorate the magnesium perchlorate




resulting in the absorption of mercury.  If, when using the secondary




amalgamation technique, magnesium perchlorate is positioned between the




amalgamator and the optical cell, a significant loss of volatile mercury




is observed after the first few runs.  Apparently, this is related to the



effect of the hot air, obtained when the amalgam is fired in the induction




furnace, interacting with the magnesium perchlorate.

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                                                                   23
    Absorbance
  80-
  6O-
   40-
   2O-
O  Dry Mg(CIO4)2


•  5  Drops  H2O


O  1O Drops H2O



•  15 Drops  H2O
                           O.4
          0.8
                                     HS
Figure 7.  Analytical Curves obtained by Direct Aeration illustrating the
          Effect of Water on Magnesium Perchlorate Deterioration.

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                                                                   2U






Without magnesium perchlorate the observed water background is related




to the temperature of the aqueous solution to be aerated as well as the




relative humidity.  Figure 8 illustrates this relationship.  This rela-




tionship is critical when a potassium permanganate solution is used



since the reduction with the hydroxylamine hydrochloride and the stannous




chloride is exothermic.






5- Carrier Gases






Compressed air and nitrogen were investigated as possible carrier gases



in the system.  With the use of magnesium perchlorate there were no dif-



ferences observed between the two gases.  Figure 9 contains the analytical




curves obtained with magnesium perchlorate with KMnOi  and H^O standards




using both nitrogen and air as the carrier gases.  Without magnesium




perchlorate, compressed air volatilized more water than nitrogen, result-




ing in a higher water vapor background.






6- Direct Aeration






Figure 10 illustrates the differences observed in the standard curves




obtained by direct aeration from KMnO, , IC1 and E^O standard solutions.



The KMnO,  curve shows the blank mercury concentration as would be




expected.  The parallel lines of the KMnOi  and H_0 standard curves show




that the rate of release of the mercury from the two solutions is very



similar.  The different slope of the IC1 curve illustrates a slightly



different rate of release of the mercury.  This partially explains the




lower curve obtained with IC1, but it still appears that not all the




mercury is being released during the reduction and aeration.

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          Absorbance
        80-
        60-
        40-
        20-
                                        60°C
                                                 Water Background
                                                 Air Flow 3
                                                 Chart 2 cm/m
                                          29°C
                                        9°C
                             Time
Figure 8.  Water Absorption at 25U nm as a Function of Water Temperature.

-------
                                                                    26
 Absorbance
6O-
4O-
2O-
                                 • •  Nitrogen
                                 O O  Air
                          (X2
O!4
                              Hg
Figure 9o  Analytical Curves obtained by Direct Aeration utilizing Magnesium
           Perchlorate with KMnO. and H20 Standard Solutions and Nitrogen and
           Air as the Carrier Gases,

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  Absorbance
6O-
                                                             KMnO,
                            Mg Hg
Figure 10.  Analytical Curves obtained by Direct Aeration of
           and H_0 Standard Solutions*
                                                              Id,

-------
                                                                   28
The difficulties with the reproducibility of the analytical results




using IC1 and the slower release rate of the mercury from the IC1



solution results in the recommendation to adopt the KMnOr solution




when studying volatile elemental mercury as it is observed in smelters.






7- Amalgamate on






Figure 11 illustrates the results obtained from amalgamating mer:-_-




aerated from KMnCr and water standard solutions.  The blank mercury




concentrations are similar to those observed with direct aeration from




permanganate solutions.  The amalgamation procedure, firing the gold-



mercury amalgam in a Leco induction furnace at a 90% variac setting in




conjunction with an LDC Mercury Monitor (range 0.6U), results in an




absorbance of 70 with a 0.2 ng sample of mercury.  As discussed pre-




viously, this is extremely sensitive and greatly limits the working




range oi" the procedure.






8- Recommended Analytical Procedure






The laboratory study has resulted in the adoption of the direct aeration




procedure in conjunction with  KMnO.  solutions.  Compressed air or nit-




rogen may be used as the carrier gas.  It is recommended that a magnesium




perchlorate drying tube be incorporated into the system.  Either the LDC




Mercury Monitor or a standard atomic absorption spectrophotometer may be




used.  The analyses of the samples  collected in the field portion of this




study utilized compressed air as the carrier gas and an LDC Mercury Monitor.



The final recommended analytical procedure is presented in Appendix II.

-------
Absorbance
                                                                         29
60-
20 -I
                                       0.1

                                       Hg
0.2
  Figure 11.  Analytical Curves obtained from KMnO.  and IUO Standard Mercury
              Solutions by Amalgamation,,          **

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                                                                 30






9- Mercury Capacity of the Gold






The efficiency of mercury retention by the gold in the amalgamators



waa determined by measuring the amount of mercury bypassing the gold.




This was studied in the laboratory by reducing and volatilizing a



standard mercury solution which was carried by an air stream (l.U




liters/minute) through a gold amalgamator.  The mercury bypassing



the amalgamator was absorbed in a KMnO.  solution using the bubbler



assembly.  This solution was then analyzed by the direct aeration




method.  Determinations were obtained from solutions containing




quantities of mercury up to 70 |ig.  The results of this study utilizing




a standard 15 mm diameter amalgamator are illustrated in Figure 12»




25 mm diameter amalgamators (shorter height of gold) showed a greater



bypass of mercury than the 15 mm amalgamators with comparable amounts



of gold.  The results of this study are dependent upon the air flow



rate and thus does not represent a true maximum mercury capacity of




the gold.  (Since amalgamation represents the mercury dissolving the



gold at the point of contact there is no ultimate mercury capacity of




the gold.)  The results of this study are used to obtain a rough




indication of the amount of gold required when obtaining a stack gas



sample.






10- Filter Analysis



The filters obtained during the isokinetic sampling of stack gases




must be analyzed for mercury to determine the total mercury concen-




tration of the gas stream.  Two analytical methods for dissolving the



particulates were investigated:




       (1)  One half of the filter was boiled in 10 ml of concentrated

-------
             15 mm Amalgamator


               O    10 gms  Gold

               A    20 gms  Gold

               B    3O gms  Gold
    5H
    4H
 .   3-
 &
51-1
    i_
    'i
                                       A
                                 A    n	n	.	-O-
                            |          V           '          T~          '           '
                           2O                    40                    60
                                           lig Hg Delivered

  Figure 12<,  Mercury Collection Efficiency of Gold Amalgamators: Mercury Bypass as a Function of the Quantity of

             Gold.

-------
                                                                32
             nitric acid for 10 minutes.  The filter was disintegrated
             with a high pressure stream of distilled water and the
             mixture was diluted to 100 ml.

       (2)   The other half of the filter was placed in a Bethge
             apparatus with 2 mg ammonium meta-vanadate (catalyst),
             5 ml nitric acid, and 10 ml ?0£ perchloric acid.  The
             mixture was heated, collecting and withdrawing the
             nitric acid.  The filter was then digested in the reflux-
             ing perchloric acid for 10 minutes.  The nitric and per-
             chloric acid solutions were combined and diluted to 100
             ml.9
After cooling, the solutions were analyzed for mercury by placing $0

ml aliquots in the interchangeable sample holders, reducing the mer-

cury with 2 ml of the stannous chloride solution and aerating the

mercury through the LOG Mercury Monitor at a flow rate of l.U liters

per minute.


Both methods dissolved nil visible particulates and produced comparable

data within experimental error.  Because of the simplicity of the

procedure, the nitric acid method is recommended and was used by this

laboratory for the field phase of this study.
         9
           "The Wet Chemical Oxidation of Organic Compositions Employing
Perchloric Acid."  The G. Frederick Smith Chemical Co., Inc., 1965.

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                                                                   33





FIELD INVESTIGATIONS






1- The Sampling Site






The samples for this study were taken at the American Smelting and



Refining Company (AbARCO) zinc smelter in Columbus, Ohio.  A flow




chart of the initial smelting process at this plant is given in




Figure 13.  The ore is roasted at 900°C in a fluid bed roaster




volatilizing the sulfur as S0?, and the mercury, presumably, as




elemental mercury (the high temperature of the roasting operation




and the fact that there is essentially no organic material present in



the ore precludes the formation of volatile organo-mercury compounds).




The particulates are removed from the gas stream by a waste heat boiler,




a cyclone and two electrostatic precipitators and the gas is then carried




through a 3-5 foot diameter horizontal steel pipe (the cross-over duct)




running about 60 feet above ground level to the acid recovery plant,




where the S02 is converted to sulfuric acid.  This duct has a 150 foot




straight section, without constriction or bends, and a single U-inch




sampling port was located in this duct about 30 feet from the down-



stream end.  The flow  in this duct is controlled by ID and FD fans,




resulting in a positive-negative pressure interface- which migrates back




and forth along the duct in the area of the sampling port.  Under normal




runrdng conditions, static pressure at the port was usually within




+ 0.£ inches of water.

-------
  electrostatic pretfip.
  cross.over duel
                                  cyclone
air
                       • sampling site
              heat exchanger
                                                                      stack
Figure 13.  Flow Chart of the Initial Smelting Process at the ASARCO Columbus,
            Ohio Zinc Smelter*

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The  gas stream in tne duct  contains  about  7 - 8£ S0? and flows at a




rate of 12,000 - 15,000 CFM.  The  average  molecular weight of the gas




has  been calculated to be 31.k and contains about $% water (figures




provided by ASARCO and EPA).






2- Sampling Equipment




The  samples for this study  were taken with a standard Model 23U3 RAC




"Staksampler" portable stack gas sampling  unit utilizing a 5-foot




glass probe heated to l50°F.  T'he  sampling train was a standard EPA




isokinetic sampling train with some  of the wet impingers replaced by




amalgamators.  It consisted of a probe mounted on a sample box and




connected to a cyclone and  filter  which were enclosed in a heated




compartment, then a series  of impingers (and/or amalgamators) in an




ice bath, followed by an impinger  containing silica gel.  The sample




box was connected to the console containing the dry gas meter and pump




by a 30-foot umbilical cord.






Modified Greenburg-Smith impingers (without the tip) were altered as




shown in Figure lit by forming three  indentations in the center (to




support a quartz wool plup  and the gold) and attaching a 28/15 pyrex




ball joint to the bottom of the straight vertical tube.  These units,




called amalgamators, can be inserted into  a standard hPA isokinetic




sampling train in place of  the standard impingers.  The interchange-




ability of impingers and amalgamators permits the use of a combination




of amalgamation and wet absorption techniques to verify the collection




efficiency of the various components.  This style of amalgamator also

-------
                                                          36
                            LJ>
Figure lU.  Illustration of the 15 mm Amalgamator.

-------
                                                                   37






allows  the  standard  isokinetic  sampling  train  to be used  for  collection




of mercury  without major  alterations  to  the  equipment.






For the purpose of this study,  a  larger  number of  impingers/amaiganators




were used in the  sampling train than  are ordinarily employed  for iso-




kinetic sampling.  The sampling box was  originally designed to hold k




impingers in the  ice bath,  including  the silica gel.  For this work,




as many as  nine impingers (including  the silica gel) were used in the




sampling train.  A maximum of six. could  normally be placed in the




sample box, and two  more  could  be taped  to the outside of the box.  By




compressing the insulation somewhat on one of  the  two sample  boxes used,




it was possible to fit seven inpingers inside  the  box and two more could




be taped to the outside.   As a  result the box  was  severely crowded and




some misalignment of the  connecting tubes was  unavoidable.  In addition,




some of the cooling  capacity reserve  of  the  box was lost  as there was




less room for the ice/water mixture and  the  impingers touching the in-




side edge of the box were not surrounded on  all sides by  the  coolant.






Since the ambient temperature during  this work was fairly low (mostly




in the 30's) and the runs were  comparatively short ( 5 -  15 minutes),




no troubles were experienced keeping  the impingers well cooled.  It




was observed, however, that when  the  ambient temperature  rose occasion-




ally to the UO's or  50's,  the ice was somewhat depleted after about




10 to 1$ mJnutes running  time.






Luring this work, a  considerable  quantify °f SC0 wao drawn through the

-------
                                                                 38
console unit.  In this procedure, the SO  is not removed at the sample



box but continues through the pump and dry gas meter.  After each run



about 1 CF of ambient air was drawn slowly through the intake of the



silica gel impinger in an effort to rinse out some of the SOo in the



console unit.  Some difficulty was experienced with the pumps in the



consoles.  The pumps were periodically found to pull erratically or



not at all.  Disassembly of the pump according to instructions furnished



by the manufacturer showed that the oil which normally lubricates the



sliding fiber vanes had congealed so that the vanes were sticking in



their slots in the rotor.  The ptmp8 were cleaned with solvent (acetone)



sid reassembled.  The oil in the reservoir was changed to a mixture of



1%% SAE 10 and 2$% kerosene as recommended by the manufacturer for



operation at temperatures below freezing.  After this treatment, the



pumps ran smoothly for two or three runs and then started to operate



erratically as before.  It was then necessary to disassemble and clean



the pumps again.  A similar difficulty was experienced with the check



valve in the metal adapter which goes from the last impinger to the



umbilical cord.  Toward the end of this work the check valve on both



adapters became corroded and stuck in a partially closed position,



causing a high flow resistance at that point.  The check valve assembly



was removed from the adapter.






3- Field Sampling Procedure



Since glassware stored openly in the laboratory may absorb traces of

-------
                                                                  39
mercury,   all  glassware was rinsed before use with the sequence: 1

SnCl2 in 2.5/5 HC1, 1:3 HMOy-H 0, distilled water, acetone, and then

dried.
The amalgamators were prepared for each run as follows.  A small plug

of quartz wool was inserted from the top and pushed into place against

the supporting indentations.  A length of ^-inch dowel rod and a

stiff  (about #10) wire are handy to help wedge the wool into position.

In earlier work, the authors used a small wad of gold wire for this

purpose, which sometimes became loose in the tube from handling and

allowed some of the finer gold particles to fall out the bottom of the

tube.  No trouble of this sort was ever encountered with the quartz

wool plug.  The gold chips were prepared by cutting up a 0.007-inch

thick  sheet of the metal into small 1/16-inch squares.  These gold

chips were placed in small crucibles and fired overnight in a refrac-

tory oven at about 600-?00°C.  At the start of each day's sampling,

the gold was removed from the oven and allowed to cool.  The gold

chips were then weighed out and poured into the amalgamator on top of

the plug, using a plastic funnel.  The amalgamator was held in a vertical

position and tapped gently to help settle the chips.  The amalgamator

was then fired in the induction furnace to insure that any
         10 J.D. Brooks and W.E. Wolfram, American Laboratory 3(5U),
(1971).

-------
mercury picked up during the handling procedure from glassware, plug,



etc., was driven off before the amalgamator was assembled into the



train.  The train sequence was then assembled for each run as shown



in Part B of Appendix II.11






After positioning the sample box at the port, the heater was turned on,



the ice compartment filled with ice and water and a leak check was per-



formed.  The probe was then connected and inserted with the tip facing



upstream (with the exceptions of Runs 61 and 62 where the tip was



positioned facing downstream).  The 0.2£-inch diameter tip was used



for Runs 1-60 and 71 - 72; the 0.50-inch diameter tip was used for



Runs 61 - 70.  After the probe and sample box had been allowed to come



to the proper temperature (probe heater setting was 100£ (l50°F)j



sample box 250°F), the pump was turned on and the flow adjusted to give



the desired sampling rate.  A stopwatch was used to time the run*  In



a five-minute run the dry gas temperature, stack temperature, etc., were



read at 2-3g minutes.  On longer runs the readings were made every five



minutes.






After obtaining the sample, the probe and sample box were taken to the



on-site mobile laboratory for the cleanup procedure.  Wide-mouthed jars,



holding a pint or six ounces and equipped with plastic caps and liners



were used to store the samples for transport to the laboratory.  These



jars were cleaned before use with the rinse sequence described above.
             See the explanation of the Data Table given on page

-------
A stock solution of 3% KMnO  in 10$ HNO. was freshly prepared every

other day.  This acidic permanganate was used to stabilize the mercury

in the samples taken from the train.^2


The following cleanup procedure was adopted to account for »11 mercury

deposited in any part of the train ahead of the silica gel.  Distilled

water was used for all rinses unless otherwise noted.

      1.  The probe, cyclone,, and the glass parts of the filter
          assembly were washed into a 1-pint jar containing
          25 ml of the 3% KMnO,  solution.  The total volume of
          this solution was measured in the laboratory prior to
          analysis.

      2.  The filter (previously weighed) was placed in a dis-
          posable plastic petri dish and marked with the run
          number.

      3»  The inside portion of the first impinger (A position)
          and the right angle connector leading into it were
          rinsed into the contents of the impinger "shell".  When
          this impinger had originally contained distilled water,
          KMnOi  was added to oxidize the S02 and mercury in
          solution.  This was found to be necessary  after initial
          attempts to analyze the SO^ saturated water for mercury
          gave highly erratic results from the evolution of S02
          when the mercury was aerated after reduction.  The
          volume of this solution was measured with a graduate
          and it was transferred to a one-pint bottle.

      U.  Each "empty" impinger in the train (and the connector
          leading to it) was rinsed into a six-ounce jar con-
          taining 25 ml of the KMnOi  solution.  The total volume
          of this rinse was measured and recorded.  This step
          was found to be necessary when it was discovered that
          moisture condensed in an empty impinger often contained
          appreciable amounts of mercury, particularly if that
          impinger was ahead of the first amalgamator.
         12R.V. Coyne and J.A. Collins, Anal. Chem. 14*,  p. 1093 (1972).

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                                                              U2
5.  Each amalgamator case and its leading connector were
    rinsed into separate jars, each containing 25 ml of
    KMnO,  solution as outlined in Step lu

6.  Each amalgamator was fired into 50 ml of the 3$ KMnOi
    solution.  The apparatus used for firing the amalgam-
    ators into permanganate is shown schematically in
    Figure 15.  The lower portion of the bubbler consists
    of a closed tube of about 100 ml capacity with a stand-
    ard taper fitting which matches a female taper on the
    body of the bubbler assembly.  These tubes were used
    as interchangeable sample holders for the KMnOu
    solutions.  The amalgamator was centered in the coil
    of the induction furnace and connected to the nitrogen
    supply and the bubbler with two female ball-joint adapters
    and two clamps.  The nitrogen flow was set at 0.5 liters
    per minute.  The induction furnace was equipped with a
    variac to control the energy transmitted to the coil.
    Firing was commenced at a setting of 60J6 and increased
    5$ each minute until the gold was glowing.  This was done
    to avoid a large "spike" of mercury into the bubbler, and
    to insure complete firing of the gold.  Laboratory tests
    on mercury aerated from aqueous solutions into UO ml of
    3% KMnO,  showed no bypass of the permanganate for 100 ng
    of mercury aerated at an air-flow rate of one liter per
    minute.  After the firing of each amalgamator, the
    sample tube was detached, the drops of permanganate
    clinging to the bubbler tube were rinsed into it and
    then the contents of the tube was rinsed quantitatively
    into a properly labelled six-ounce wide-mouthed jar.
    The amalgamators were fired in reverse order (i.e., A£,
    A, , A,., A , AO  to minimize contamination of successive
    samples by drop carry-over.  After firing, the amalgama-
    tors were assembled into the train to be used for the
    next run of the day.  After the series of amalgamators
    had been fired, the bubbler apparatus and all of the
    sample tubes were cleaned, using the rinse procedure
    described above.  It was found necessary to replace the
    tygon tubing connecting the amalgamator to the bubbler
    for each run in order to avoid contamination of succeed-
    ing samples by mercury adsorbed and then desorbed by the
    tygon.  This tygon tubing was kept short (2-?g inches)
    to minimize mercury loss.

    Upon receipt in the laboratory, each sample (from an
    amalgamator) was- diluted to 100 ml in a volumetric flask
    just prior to analysis.

-------
                                          Ampoule Stopper
                            3-way Stopcock
                    28/15 Ball-joint





                     Amalgamator
                     Induction  Furnace
           To Vent
Bubbler
                                                 \S     KMnO4  Solution
Nitrogen
        Figure l£.  Apparatus used for Firing the Amalgamators*

-------
      7.  The volume(s) of the KMnO,  backup solution(s) (where these
          were used to back up the gold train) was measured with a
          graduate and the solution was transferred to a one-pint
          jar.  Any permanganate stain remaining on the impinger was
          removed with a few drops of 10% hydroxylamine hydrochloride
          followed by a rinse with distilled water.  The volume of these
          rinsings was measured and they were added to the perman-
          ganate in the sample jar.

      8.  A $0 ml blank of the permanganate solution was taken each
          day, placed in a six-ounce jar, and sent to the laboratory
          with the samples.
A field, record was kept of all data recorded during the run and of each

sample taken for analysis from the train.  At the end of each day the

sample jars were packed in cartons and transported to the laboratory

for analysis.


li- Laboratory Analytical Procedure


Upon receipt of the samples by the laboratory, the volume of the probe

and cyclone washings were measured and recorded along with the total

volume of each of the other solutions, with the exception of those

obtained from firing the amalgamators.  The latter were each diluted to

100 ml in a volumetric flask.  A suitable aliquot of each of these

samples was then withdrawn by pipette and analyzed for mercury by the

direct aeration procedure.  The filters were analyzed by digestion

with nitric acid, followed by analysis using the direct aeration tech-

nique.  The procedures used are those developed under "Laboratory

Investigations" and are described in detail in Appendix II.

-------
RESULTS AM) DISCUSSION


1- The Data Table


The data for each of the samples taken during this study is listed in

Appendix I.  Because of the large number of items associated with each

run, the table is divided into Parts A and B on separate pages.  In

general, Part A contains the data taken in the field and Part B con-

tains the data resulting from the laboratory analysis of the samples.

Where there is more than one entry for a run in a column of Part A,

the entry represents data taken every five minutes of a 10- or l£-

mimite run.  In Part B, under the general heading of "Train Configu-

ration" there are four horizontal lines of data across Columns A

through H.  The letter of the column heading represents the position

of the impinger or amalgamator in the train sequence, counting from

the filter (position "A" is the one immediately following the filter,

"B" is next, etc.).


The topmost of the four horizontal data lines for each run is a code

describing the contents of the impinger or amalgamator in that position:

               H   -   Distilled water, 2$0 ml

               E   =   Empty impinger

               A   =   20 grams of gold chips in each amalgamator of
                       the series unless another amount is indicated.

               K   =   250 ml of saturated KMnOi  solution unless
                       some other quantity is indicated.
                           ml 12 SnClg in 2-l£ HC1

-------
                                                                 U6


               HS   =   250 ml distilled water used for the run, then
                        13 ml 2.0$ SnCl2 in $0% HC1 were added to the
                        impinger and ambient air drawn through at that
                        point for about 3-5 minutes in an attempt to
                        aerate the mercury in that impinger onto the
                        following amalgamator.

The second of the four horizontal lines for each run gives the total

number of micrograms of mercury found in that impinger or amalgamator.

Under this is given in parentheses the micrograms of mercury found

in the amalgamator case and connector washings.  On the fourth line

the distribution of mercury among the amalgamators is given on a

percentage basis.  This figure is useful for comparison of the perform-

ances of the amalgamator trains used in the various runs.


Under the column headed "Total Hg", the total mercury found in the entire

train is given.  Under this value is listed the percentage of that total

found in all parts of the train except the permanganate backup solution.

This gives a figure which corresponds to an experimentally determined

percentage of total mercury recovery for the system, as it would be used

for longer runs, without KMnOi  backups.  It also gives a useful indication

of the efficiency of the amalgamator train when comparing runs.  Under

the column headed "Filter", the topmost figure for each run gives the

number of micrograms of mercury found in the filter for that run.  Under

this figure the total weight increase of the filter  (weight of particul-

ates collected on the filter) is given in grams.


2- Sampling Train Configuration


The initial runs (1 - 16) of the field study were performed to determine

the optimum combination of amalgamators, empty impingers, and "scrubber"

(a liquid-filled impinger ahead of the amalgamator train to help remove

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                                                                U7





moisture, sulfuric acid mist, etc,).  The train configuration was



varied for eacti run and each combination was generally done in



duplicate and in random order.  Sampling rate was ^0.5 CFM.





Runs 7, 11, 12, and 13 were performed without any scrubber solution



ahead of the amalgamator train.  The configuration used and the



relative distribution of the mercury found in the amalgamators is



given below in Table 2.








                               TABLE 2



                     Sampling Train Configuration
Run Configuration Hg Distribution on
13 AAAEEK 28.1 32.2
12 EAAAEK 81.5 10.9
7 EEAAAK U5.5 U8.2
11 '* 86.9 7.5
Amalgamators
39.8
7.6
6.2
5.6
The results suggested that maximum mercury pickup by the first amal-



gamator would be obtained in position "B" or nCn.






3- Initial Scrubber Solution





Runs 1, 2, U, 5, and 6 were performed using 250 ml of distilled water



for a scrubber in position "A", with the amalgamator train starting at



position "Brt.  Runs 8 and 1U were performed in the same manner but with

-------
an empty impinger in position "B" and the amalgamator train starting


at Position "C".  The results from these runs are given in Table 3.




                              TABLE 3


                  Distilled Water as the Scrubber
Run
1*
2*
u*
5*
6
8
1U
C onf igur ation
HAAAK
it
n
II
II
HEAAAK
it
Hg Distribution on
57.U
96.7
2li.li
U7.0
72.6
68.1
3U.1
16.9
2.U
61.7
33.0
8.1
31.3
1U.6
Amalgamators
25.6
1.0
13.0
20.0
19.2
0.5
51.2
              *
               The pump ran very erratically during these runs.
These results suggested that, within the limits of the reproducibility


obtained there was no obvious advantage for either of these configura-


tions over the other in terms of train efficiency; both produced at


least one very good run (e.g., Runs 2,8) and some poor runs (5, lU).


The cause of the inconsistent results obtained with these and other of


the earlier runs was later discovered to be contamination of the gold


chips caused by some substance evolved from the quartz wool plugs


during the pre-firing of the amalgamators.  This problem and its solu-


tion is discussed in more detail in Section £, Critical Parameters.



It was noted that a significant amount of condensate was collected, in


the "Brt position, while the "C" position showed very little condensate.


This was observed whether Position A contained a scrubber or an empty


impinger.  It was therefore decided to adopt the practice of starting

-------
 the amalgamator train at the "C» position to minimize condensation in




 the amalgamators.  The scrubber solution in the "A"  position was  found




 to collect a significant amount of mercury.  Some mercury was  also



 found in the condensate collected in the empty "B" impinger.   It  was



 decided to try a 1$ solution of SnCl2 as the scrubber solution to see



 if this would minimize the retention of mercury in the scrubber.   Two




 methods were tried to accomplish this.  In the first method, the  im-



 pinger in the "A" position was sijnply filled with 250 ml of 1% SnCl2




 in 2-5$ HC1.  In the second method, 250 ml of distilled water  were




 used in the "A"  impinger and at the end of the run about 13 ml of a



 2C$ SnCl2 in 50$ HC1 solution were added to the inlet of the "A"  im-



 pinger and about 3-5 CF of air was drawn through the train at  that



 point to aerate  the reduced mercury onto the first amalgamator.  The



 results of these runs are given in Table U.






                               TABLE U



                   Stannous Chloride as the Scrubber
Run Configuration

3 SAAAK
9 SEAAAK
15
10 (HS)AAAK
16 »
Hg Distribution on

' - 85.0
67.6
23.6
U.8
21.6
(*)
10.2
Hi. 7
U3.5
9.6
12.8
Amalgamators

U.8
17.6
33.1
85.6
65.5
When the SnCl2 solutions from the "A" position were taken for analysis,



they were found to require a large addition of KMnOi for oxidation of



the contents, increasing the blank correction required.  After addition

-------
                                                                    50



of the required amount of permanganate, some precipitate was noted in


the solution and the analysis of these solutions showed poorer reprodu-


cibility than analyses obtained from the distilled water scrubbers.


The aeration attempt did not prove to be successful; the "A" solutions


of Runs 10 and 16 were found to contain mercury even after the aeration


step*
On the basis of these results it was decided that the use of SnClg as


the scrubber offers no advantage and may present a disadvantage over


the use of distilled water.  The results obtained on addition of the


      followed by aeration suggested the possibility of mercury being
washed through the train by SnCl  vapors or droplets carried from the


first impinger.  It was therefore decided to use only distilled water


as the scrubber for the remainder of this work.



U- The Use of KMnO^ Solutions



For most of the runs in this study a solution of KMnO.  in 2% HNCU was


used in one or two impingers as a back-up system to catch any mercury


going through the amalgamator train.  At the high levels of SO- en-


countered, a saturated solution of KMnOi  was completely decolorized in


U - 6 minutes, depending on the sampling rate, SO- concentration, etc.


It was found to be most practical to prepare the backup impingers
                                                                 I

using KMnOi  as follows.  The HNO^ and distilled water was added to the


impinger "shell" (250 ml for sampling rates of 0.5 CFM or less; 150 ml


for sampling rates above 0.5 CUM) and then sufficient solid KMnOj was

-------
                                                                 51


weighed out and added to the water  (.about 3-5 grams per CF of sample

to be taken).  The resulting solution contained excess KMnQ.  crystals,

but these dissolved as the solution was reduced during sampling.


Several problems were encountered with the use of KMnO.  for back-up

solutions.

      1.  It was apparent that more than two of the permanganate
          backups would be required to catch all of the mercury
          in those cases where a substantial quantity of mercury
          was passing through the amalgamator train.  For example,
          Runs 1*7-62 were made using two KMnOi  back-up solutions
          in series.  In these runs some mercury was usually
          found in the second permanganate solution, although
          normally less than the amount found in the first one.

          Eight impingers and amalgamator units were already being
          used in the train and the pressure drop in the train
          was great enough so that  the pump was only drawing about
          0.7 CYK at maximum effort (pump vacuum at 25 inch Hg).

      2.  Since the permanganate backups were just before the
          silica gel, carryover from these solutions into the
          silica gel often completely ruined it in about £-10
          minutes.  At flow rates above 0.5 CFM the volume in the
          permanganate impingers had to be reduced to 150 ml in
          order to avoid serious loss from violent "bumping".
          The heat of reaction as the KMrD.  was reduced by the S02
          (the permanganate impingers became quite warm to the
          touch) aggravated the carryover problem and caused im-
          pinger temperatures to go as high as ll£°F after 15
          minutes of sampling.

      3»  When longer sampling times of 10rl5 minutes and/or
          higher sampling rates called for large amounts of KMnQ^
          (50-80 grams) in 150 ml of water, the solution resembled
          a thick paste after the run.  The efficiency of such a
          "solution" is very questionable.


In spite of these problems encountered with the permanganate solutions,

it was felt that they could be made to yield some useful information

for our purposes.  The use of more than two permanganate backups

-------
                                                                 52


was not felt to be practical at this point.  Instead, it was decided

to use the data obtained from one or two permanganate backups as a

check on the performance of the amalgamator train, with an understand-

ing of its limitation as pointed out above.  In other words, it was

decided that the highest priority should be to improve the performance

of the amalgamator train.  If the amalgamation train could be made

efficient enough, one or two permanganate backups would prove the point;

if the amalgamators could not be made efficient enough, neither system

would be practical.  Subsequent results vindicated this approach to

the problem.


5- Critical Parameters


Using the optimum train configuration, HEAAAK (determined as described

above), a series of five-minute runs was performed at various sampling

rates in the range of 0.211 to 0.833 CM to see if the sampling rate

had any effect on the collection efficiency of the amalgamators (Runs

17-30).  The results were inconsistent.  Some runs where the amalgam-

ator sequence showed an orderly progression in the percentage distri-

bution of mercury also showed a significant percentage of the mercury

passing through the amalgamator train, as shown by the amount of mer-

cury found in the permanganate backup solution (e.g., Runs 1? and 214.).
           A useful way to compare this aspect of total train efficiency
between runs is the figure given in the Data Table, Part B, under the
column headed "Total Kg".  Under the figure for the total mercury found
in the train is a figure which represents the percentage of that total
found ahead of the permanganate solutions.

-------
                                                              $3





Some runs showed a recovery ahead of the permanganate of 9%% or more,



but the distribution of mercury among  the amalgamators appeared to be



nearly randomn  ( e.g., Runs 25,  27).   Neither the distribution of mercury



in the amalgamators nor the percentage of mercury found ahead of the



permanganate backups showed a clear relationship to sampling rate.





Runs 31-36 were performed using the same train configuration as above,



the sampling times being varied from one to twenty minutes at a



sampling rate of approximately  0.5 CM.  The results of this series



showed the same kind of inconsistency  in results as above.  For example,



the percentage of mercury found ahead  of the permanganate averaged less



than that found in Runs 17-30,  although both shorter and longer sampling



times were used.  In this series of runs, only about 60% of the mercury



was recovered ahead of the  permanganate solutions.  In an attempt to



improve on this figure several variations in the system were tried.





Runs 37-liO were made using  33 grams of gold in each amalgamator (an



increase of 6$% in the total amount of gold in the train for Runs 37



and 38).  In Runs 39 and 1*0, the amalgamator train was moved back one



positionj in Run UO and extra scrubber was inserted to give the sequence:



       Run 39         HEEAAK            (66 gm gold total)



       Run UO         HHEAAK           (66 gm gold total)



None of these variations produced any  improvement in the performance




of the amalgamator train.

-------
                                                                  5U





Runs Ul-£l were performed using five amalgamators in series, starting



from the filter, each containing 20 grams of gold.  It was hoped that



distribution data from the increased amount of total gold divided



among the five amalgamators might provide an insight into the cause of



the inconsistent results obtained up to this point.  Sampling times of



five to thirty minutes and sampling rates of about 0.3 to 0.7 GEM were



employed.  Inspection of mercury distribution data for these runs



showed that the expected orderly progression of mercury concentration



through the amalgamator train was largely absent.  The percentage of



mercury recovered ahead of the permanganate ranged from 3356 to 93%•



Since previous work had given better results than this, using less



gold, it was tentatively assumed that the gold was being effectively



"poisoned", either by some substance from the stack, or by some step



in the handling procedure.  The lack of correlation between sampling



time or rate, and the efficiency of the train discounted the former



possibility, so we turned our attention to the handling procedure being



used.  To see if the trouble was coming from the pre-firing step,



Run U9 was performed using amalgamators prepared in the same manner as



before,, except that the pre-firing step was eliminated.  The gold was



placed in the amalgamators directly from the firing crucibles after



cooling.  This simple modification proved to be the key to the 'problem:



the first amalgamator of Run U9 picked up 92$ of the mercury found in



the amalgamator train.  This was a much higher figure than any ob-



tained in a previous run.  Runs $0 and !?1 were performed in the manner



previously used for the second and third runs of any day}  the

-------
                                                                  55


amalgamators were placed in the train after the normal firing procedure

used for the previous run (first run of the day).  The results showed

that firing the amalgamator with the quartz wool plug in place causes

a progressive decrease in that amalgamator's ability to remove mercury

from the sample stream.  To make sure of this point, Runs 52 and 53

were performed using gold fired overnight in tne oven and not pre-fired.

Run 5U was performed using the same gold, amalgamators, and quartz wool

plug as Run 53.  The pertinent data from Runs U9-5U is shown in Table 5.
                             TABLE 5

       The Effect of Firing the Amalgamators in the Presence of the
                          Quartz Wool Plug
Run
k9
50
51
52
53
5k
Fired with
Quartz Wool
Plug
in Place
No
Yes
Yes
No
No
Yes
Percentage of Total
Amalgamator Mercury
Found on First
Amalgamator
92.2
6U.O
U7.9
9U.U
9U.8
Ul.6
Percentage of
Total Mercury
Found Ahead of
Permanganate

52.6
61u2
93.6
95.8
1*5.7

-------
From these results and the results of subsequent work, the following

conclusions were drawn:

      1.  The heating of the quartz wool plug during firing of the
          gold causes the plug to give off some substance which
          collects on the surface of the gold (presumably while the
          gold is cooling) partially coating it and thus decreasing
          the effective surface area available for amalgamation of
          mercury from a flowing gas stream.

      2.  In the laboratory, a piece of the quartz wool was weighed,
          fired for two days in a crucible in the refractory oven
          and then reweighed.  The results were:

                  weight before firing         0.2l;22 g
                  weight after firing          0.2U08 g
                      weight loss              0.001U g

               percentage weight loss     =    0.58$

          Only a small amount of this volatile material is necessary
          to desensitize the gold.

      3»  The condition of the gold, (cleanness of the surface)  is
          probably the single most important factor affecting the
          efficiency of the amalgamators.

          Firing in an oven seems to be the best way to clean the
          gold before use and between uses.

      U.  Since the condition of the gold was found to be such a
          large factor in the performance of the amalgamation train,
          it was obvious that the previous study of the dependence
          (if any) of collection efficiency on sampling rate and
          sampling time should be at least partially repeated using
          only freshly (oven) fired clean gold*

-------
                                                                  57
6- Collection Efficiency of the Amalgamators


The  collection  efficiency of tne  amalgamator  train was studied as a

function  of  sampling rate,  sampling  time,  and the total amount of mercury

collected..   This was done for a train of three amalgamators containing

20 grams  of  gold each,  and for trains of four and five amalgamators,

each containing 30  grams of gold.  Clean gold,  not fired in the presence

of the quartz wool  plug,  was used for these studies.  The collection effic-

iencies of Euns 55-72 are presented  in Table  6.


a. Theory


Consider  a series of identical amalgamators (tne same size and shape,

each containing the same amount of gold, the  same distribution of

particle  size,  void fraction,  etc.).   If we assume that the amount of

gold is much larger than the amount  of mercury to be collected (i.e.,

the  accumulation of mercury on an amalgamator during sampling does not

alter its collection properties; that it is operating well below

capacity), a relationship can be derived between the ratio of mercury

found in  any two adjacent amalgamators and the collection efficiency
                                    i
of one or any total number  of  amalgamators.

           Let  r  = the  fraction of mercury entering an amalgamator
                     which  is  trapped by the gold.  This can be called
                     the  "trapped fraction" of a single amalgamator.

then    (1 -  r)   = the  fraction of mercury passing through that amal-
                     gamator which is not trapped by the gold..  This
                     can  be  called the "escape fraction" of a single
                     amalgamator.

If n amalgamators are connected in series, the fraction of the total

mercury passing through the  nth amalgamator, fe n, is given by:

-------
         TABLE 6
                                               58
Collection Efficiencies
Run
No.
55
56
57
58
59
60
61
62
63
6U
65
66
67
68
69
70
71
72
Metered
Gas Volume
CF
1.533
3.609
3.1U6
- U.899
7.2UO
6.861
10.738
6.UOU
3.156
U.897
2.3H
7.830
8.838
10.U06
3.816
U.7U2
U.215
6.923
Percent of Amalgamated Mercury
in each Position
C
88.6
92.3
90.7
93.3
91.3
67.6
59.3
7U.U
76.1
86.7
82.1
98.7
97.1
89.0
8U.8
79.1
61.5
79.U
D
5.7
5.7
7.7
5.U
5.9
25
31.8
21.U
1.1
3.2
0.0
0.2
1.0
10.3
13.8
16.5
9.5
12.3
E
5.7
2.0
1.6
1.2
2.8
7.U
8.9
U.2
0.7
3.5
0.0
0.1
0.6
o.h
0.6
2.U
10.5
2.8
F
K
K
K
K
K
K
K
K
o.h
3.U
3.1
0.0
0.6
0.3
0.9
1.9
10.7
3.0
G
K
K
K
K
K
K
K
K
21.6
3.2
m.8
1.0
0.7-
SG
K
K
7.8
2.5
Percent of Mercury
Recovered before
Permanganate Backup
96.9
96.6
99.0
97.6
9U.5
95.1
91.1
89.1
99.7
#
98.8
•«•
*
*
100.0
98.3
*
#
             K  -  Acidic Permanganate Scrubber
             SG -  Silica Gel
             •«•  -  Train did not contain an acidic
                   permanganate scrubber

-------
                  f      =   (1  -  r)n                            (1)
                   S jli

The fraction  of  the total mercury trapped  by the nth amalgamator, f.   ,

is equal to the  fraction passing through the (n-l)th amalgamator times r:


                  f      -   r(l - r)11"1                          (2)
                   T»f U

The expansion of terms  (1)  and (2)  for  each  amalgamator is given in

Table 7.

                             TABLE  7

     Theoretical Distribution  of Mercury in  a Series of Amalgamators

   AmalgamatorFraction of TotalFraction of Total
       No.            Trapped  by Amal.        Through Amal.
                            f                      f
                            t,n                    e,n


      1                     r                     1-r
      2                  r-r2                 l-2r +  r2
      3               r-2r2 +r3            l-3r +3r2 -r3
      U            r -3r2 +3r3 -r^       1  -Ur +6r2 -Ur3 +r4
      5          r -Ur2  •|-6r3 -Ur^ -t-r^   1 -^r +10r2 -10r3
Similarly to Equation (2), the fraction of the total mercury trapped

by the (n -I)**1 amalgamator, f+ n_i> is equal to the fraction passing

through the (n -2)nd amalgamator times r:


                 f.       =  r(l-r)n-2                        (3)
                  t,n-l

If T = the total n-g of mercury passing through the train, the ^ig of

-------
                                                                  6o
mercury trapped by the n1 amalgamator, t , is given by
                            Tf
                                     11-1
                     t   =  T r(l -r)11-                        (5)
                      n



and the ng of mercury trapped by the (n -l)th amalgamator is given by





                     W  T ft,n-l




                    Vi =  T r^ -r>n~2




Dividing (5) by (7) we obtain:




                    tn          T r(l -r)11-1
                                T
                                                 "  (1 -r)     (8)
Thus, the "escape fraction", (1 -r), can theoretically be obtained



directly from the ratio of total mercury found in any two adjacent



amalgamators.  In actual practice, however, where the "escape fraction"



is low, only the first and second amalgamators in the series show



enough mercury to give a value of t^ and t? with sufficient relative



accuracy to calculate a meaningful value for (1 -r) .  For this reason,



calculations of tjj/tj^ in this report have been confined to the first



two amalgamators.





The fraction of the total mercury trapped by the whole series of n



amalgamators, F.  , is given by the sum
              Ft,n  =  ft,l  +ft,2  +ft,3

-------
                                                                  61
Since                    F     + f     si                    (10)
                          t,n     e,n                          v  '

Substituting (1) into (10) we obtain:

                         Ft,n -  1 - (1 -r)n                   (11)


Equation (11) can be used to calculate:

            A.  The maximum "escape fraction" permissible to
                achieve a given percentage of total mercury
                recovery for any number of amalgamators.

            B.  The percentage of total mercury recovery for an
                experimentally obtained "escape fraction" when
                using any given number of amalgamators*

            C.  The number of amalgamators necessary to obtain
                a given percentage total recovery if the
                "escape fraction" for the amalgamators is
                known.
            For example, if we wish to obtain a 95% total recovery
            using three amalgamators, from equation (11),
            We must obtain a value for t2A1 of less than 0.368

            in order to achieve 95% recovery using three amalgamat-

            ors in the train.


The maximum t2/t. permissible to achieve a 95% total mercury recovery

for any number of amalgamators is given in Table 8.

-------
                                                                62



                          TABLE 8
                                           »

            Maximum Escape Fraction for 95£ Recovery





     No. of Amalgamators           Maximum t/t^ for 9$% Recovery
            2                                  0.22U
            3                                  0.368

            h                                  O.U73
            5                                  0.5U9
b. 20 grains of Gold per Amalgamator




For Runs 55-62, the train sequence was HEAAAKK with 20 grams of gold in


each amalgamator.  Sampling times of 5, 10, and 15 minutes, and sampling


rates from 0.30? to 0.722 CFM were used.  Since Runs U9, 52, and 53 were


also performed with 20 grams of gold not fired in the amalgamator before


use, the data from these runs is also included here.  All of these runs


were found to give much better and more consistently good results than


those obtained previously.  The amount of mercury found showed a pro-


gressive and orderly decrease through the series of amalgamators (see


Table 6)5 the first one retaining about 90/5 of the total "amalgamator


mercury11 and the last one about 1-6^.  The percentage of mercury recovered


ahead of the permanganate backup solution showed a corresponding improve-


ment (the median value was
In order to discover whether the collection efficiency of the amalgam-


ators showed any dependence on the sampling fate, the ratio of t2A1


was calculated for each of these runs and plotted against the sampling

-------
                                                               63
rate, as shown in Figure 16.  The resulting curve showed almost no




dependence of tne collection efficiency on sampling rate witnin the



range of sampling rates studied.






The ratio tg/t  was also plotted against t« + t, as shown in Figure 17,



to see if tnere was any decrease in collection efficiency as the amount



of mercury collected increased (saturation effect).  This plot showed



no dependence of collection efficiency on the micrograms of mercury




collected.  The dotted lines shown on Figures 16 and 17 represent a




tp/t-, value of 0.368, corresponding to a total amalgamator train




efficiency of 9$% for 3 amalgamators.






Figures 16 and 17 both show all values of t2/t-, clustered below



t,,/t  = 0.1, except for Runs 60-62, which are noticeably higher.  The




discrepancy of these runs may perhaps be explained by reference to




some observations made while these samples were being taken and then




fired.  During the cleanup of Run 60, a considerable quantity of what




appeared to be a black, tarry substance was found in the cyclone and




filter assembly.  This substance was not soluble in water but was sol-




uble in acetone.  In firing each of the amalgamators from this run, a



quantity of smoke was evolved which condensed on the portion of the




amalgamator tube above the gold as an oily film.  On Run 61, a consid-




erable quantity of the black tarry substance was found condensed in




the first amalgamator tube after it had been fired and the quartz wool




plug was quite dark looking.  The filters from Runs 60-62 were also




much darker in appearance than usual.  These observations suggest that

-------
      0.6-
      0.4-
                                            Tram:HEAAAKK
                                            20g. of Gold
                                            o  5min.
                                            A lOmin.
                                            0 15m in.
                                         "run 6(J
                                                                         o
                                                                      run 61
                                                                     (tar on 1)
     0.2-
                                        (oily smoke)
                                                      run 62
             0.2
     0.4
Sampling Rate (CFM)
0.6
Figure 16.  Collection Efficiency vs. Sampling Rate for 20 Grains of Gold per Amalgamator,,

-------
                                              Train: HEAAAKK
    to/t                                       20 g. of Gold
                                              o  5min.

                                              AlOmin.

  A                                           DlSmin.
  O.o-
                                 D

                              run 61

                             (tar on 1)



  0.4-


                                                                                 run 60

                                                       4                        (oily smoke)

                                                     run 62


  0.2-
                       '	'—S     l     !

                              Total ug Hg on 1st & 2nd amalgamator
Figure 17.  Collection Efficiency vs. Total Mercury Collected for 20 Grains  of Gold per Amalgamatorc
                                                                                                ON
                                                                                                vn

-------
                                                                   66






some abnormal variation in the ore being roasted, or a malfunction in




some part of the equipment at the plant may have been responsible for




releasing some high boiling organic substance into the gas stream where




it was collected by the sampling unit and a portion of it was deposited




on the gold.  This seems the most likely explanation, as the first




amalgamator in each series seems to be the one most affected, the ty^



ratio in each case being less than t2/t, for the same run.  In this




connection it is interesting to note that the percentage of mercury



recovered ahead of tne permanganate backups did not decrease very much




for these three runs, the figures for Runs 60, 61, and 62 being 95*1.%,




91.1$, and 89.1$, respectively.






These results point out once again the fundamental importance of the




condition of the gold, and suggest that it would be wise to employ




enough gold in the amalgamator train to provide a generous reserve




capacity, as the deposition of any oil or tar on the gold (which may




be inadvertent or unavoidable in an actual sampling situation) will




greatly decrease its collection efficiency.  Concluding that this




approach would prove to be the best one to the problem of obtaining




consistently high collection efficiency while sampling under actual




field conditions, we made a series (63-72) using what was considered



to be our "optimum train."






c.  30 grams of Gold per Amalgamator






Thirty grams of the gold chips used in this study make a column




3.2 - 3.7 cm high in the amalgamator tube.  This was about the tallest

-------
                                                                   67
column of chips which  could be uniformly heated by the present coil

in the induction furnace  (other  sized  coils  can be used in this furnace

if desired).  Since a  total of only  l6u grams  of gold was available for

this study, we made a  series  of  runs (63 - 72) using a train of either

four or five amalgamators with thirty  grams  of gold in each one.  Of

this series, Runs 63,  6£, 69, and  70 also contained a permanganate

backup solution to check  the  efficiency of the amalgamator train.

Sampling times of S, 10,  aJ«i  15  minutes were used and the sampling rate

was varied from 0.281  to  0.763 CFM.  Run 72  was a 15 minute run taken

under isokinetic conditions.  These  runs showed a large percentage of

the total "amalgamator mercury"  on the first amalgamator and an orderly

decrease in mercury through the  train.  The  total percentage of mercury

collected ahead of the permanganate  backups  was very high, ranging from

98 to 100/5.  The ratio t2/tn  vs. sampling rate is shown in Figure 18.

From this experimental data,  there does not  seem to be any dependence

of collection efficiency  on the  flow rate.   The ratio t2/t^ is also

plotted against t2 + t-j_ in Figure  19.  Again,  there does not appear to
                                   1
be any dependence of collection  efficiency on  the total amount of mer-

cury collected, at least within  the  range studied.  The collection effi-

ciency also appears to be independent  of the sampling time used, and

our experience with these and earlier  runs (e.g., Runs 36, 38, U6) does

not suggest that 15" minutes is the maximum feasible sampling time.


The data from Runs 63-72 shown in  Figures 18 and 19 show the same

kind of clustering referred to above.  The values of t2/t-L for

-------
   0.4
                                              Runs 63-72
                                              30g. of Gold
                                              o  5min.
                                              AlOmin.
                                              DlSmin.
   0.2-
                                         Q
                                      isokinetic
                                         run
                                                        D   ©
        	1           ]       v/    ,  w        |            (           |
                                0.4                    0.6                    0.8

                                   Sampling Rate (CFM)



Figure 180  Collection Efficiency vs. Sampling Rate for 30 Grams of Gold per Amalgamator,!

-------
°'4-l                                               Runs 63-72
                                                   3Og. of Gold
                                                   O  5min.
                                                   AlOmin.
0.3
0.2
0.1
QlSmin.
                D w        D
                        isokinetic
                           run
               A
                  C
                                                T	"	1	r
                          10                     20                     30                    40

                                   Total yg Hg on 1st & 2nd amalgamators


  Figure 19.  Collection Efficiency vs0 Total Mercury Collected for 30 Grams  of Gold per Amalgamator.

-------
                                                                  70






Runs 63-67 are clustered below 0.05>, while t2/t-L for Runs 68-72 are all




in the range of 0.11 to 0.21.  All values were, however, well under




the to/t^ ratio of O.lj.7 corresponding to 95% efficiency for the train




(see Table 8).






Run 68 was taken at about 1:30 pm on December 6, 1972.  The ASARCO




plant had been having some trouble with their acid recovery plant,




which had started up around noon after having been shut down in the




morning.  The roaster operator on duty informed us at that time that




one of the two electrostatic precipitators had not been working for




some time and that the other one was not working properly.  This could




explain the slightly lower collection efficiency obtained on this and




the following runs.






7- Sources of Error






The errors which could be encountered in the application of this method




to an actual sampling situation might be broadly classified as sampling




errors or analytical errors.






a. Sampling Errors




The most likely sampling error, in our opinion, is the failure to col-




lect all of the mercury in the sample stream due to insufficiently clean




gold.  Contamination of the gold from the gas stream being sampled is,




of course, minimized by the use of the normal cyclone and filter assemb-




ly.  The wet scrubber solution next to the filter followed by an



empty impinger is also an aid here.  In our experience these items

-------
                                                                   71





undoubtedly help but do not eliminate the problem of gold contamina-




tion during sampling.  Our most successful approach has been to use




enough gold in enough amalgamators to provide a reserve capacity in



case such contamination does occur.  Examination of the data from the



amalgamator train should enable one to tell if such contamination has




indeed occurred, and allow at least a rough estimate of its severity




to be made.  3y using five amalgamators in the series, each containing




30 grams of gold, we were able to obtain very high train efficiencies,




in spite of a certain amount of gold contamination (at least for 1$




minutes of sampling time).  We do not know how our sample source com-



pares to others with respect to such contamination problems.






b. Analytical Errors



Special precautions should be taken to avoid mercury contamination of




the glassware used.  The normal precautions of good analytical tech-




niques apply here.  Reagent blanks and permanganate blanks should be




periodically checked and appropriate records kept.  Vie used one lot of



KMnO.  for our work.   Careful determination of the mercury blank for the




lot used in this study gave a value of 0.012' tig of mercury per gram of




KMnO.  and this value was used as a correction factor for the permanganate




backup solution analyses.  In addition, daily blanks were taken from the




working solution of 3% KMnO, , 10£ HNO  used for preserving the samples,




and these blank corrections applied to the analytical results obtained.






For earlier runs of this study, a single piece of tygon tubing, about




18 inches long, was used to connect the amalgamator to the bubbler

-------
                                                                  72






while firing the amalgamators.  This piece of tubing was washed out



along with the bubbler between runs.  On Runs 63 and 6£ some contam-




ination of the last amalgamator was suspected due to the unexpected and




otherwise unexplainable amount of mercury found in the last position.




It was suspected that the tygon tubing was adsorbing mercury when high




concentrations were present in the nitrogen stream (from firing the




first amalgamator of the previous run) and desorbing it again during




subsequent firings when heated nitrogen (containing little or no



mercury) was flowing through it.  The washing procedure was not clean-



ing it thoroughly.  On Runs 67-72, the tygon was shortened to 2-5g




inches (to minimize loss by adsorption on the tygon)  and replaced with




a new piece for each run (to eliminate contamination of the solution




obtained by firing the last amalgamator in the train, which was also




the first one fired in the series).  There was no further evidence of




cross contamination between subsequent runs.






8- Application to Isokinetic Sampling






Isokinetic sampling is usually performed at a sampling rate of 0.5 to




0.8 CFM.  Since quantitative recovery of mercury from the gas sample




was obtained at these rates, and in view of the independence of recovery




on sampling rate, there is no reason why this procedure could not be




used for isokinetic sampling.  Run 72 was, in fact, taken isokinetically,




and the data sheets for this run are included in Appendix III.

-------
CONCLUSIONS






The results of this study show that the gold amalgamation technique, for




the collection of mercury from a gas stream containing a high percentage




of S02, can achieve quantitative collection efficiencies at the sampling




rates normally used for isokinetic sampling.  Figures 16 and 18 show




quantitative collection independent of flow rate in tne range of 0.3 to




0.8 CFM.  Isokinetic sampling is carried out in the range of 0.5 to 0.8



CFM showing that the procedure developed in this study can be used




isokinetically.  One run was made under actual isokinetic conditions,




and the collection efficiency achieved was the same as the efficiencies




obtained with the same equipment and procedure under non-isokinetic




conditions.  Since some mercury was always found in the probe, cyclone




and filter assembly, a sample taken for the purpose of establishing



total emission of mercury from a source should be taken isokinetically




to insure representative sampling.  The standard isokinetic sampling



procedure is to sample for about five minmtes at each traverse point so




that total sampling time is about one hour.  Although sampling times of




15> minutes or less were used with the train and procedure as finally




optimized in this study, none of the results obtained suggest that longer




sampling times could not have been used with equally good results.






Some of the data obtained suggests that collection efficiencies are




lowered by volatile materials which get through the cyclone and filter




and one initial wet scrubber and coat the gold.  In this study a series




of five amalgamators, each containing 30 grams of gold chips, provided a
                                73

-------
                                                                    7U


sufficient reserve capacity to compensate for this problem as it was

encountered in this stack.  Since other stacks on other plants could be

significantly different with respect to the amount of such volatiles, it

might be advisable (as least initially) to have some kind of feedback on

the sampling efficiency obtained so that additional samples could be

taken if necessary before equipment and personnel have vacated the

sampling site.  This could be accomplished by on-site analysis of a

portion of the samples obtained.


Some suggestions are also offered here for certain improvements in the

equipment which the authors feel may make the sampling and analysis

operations easier and more efficient,  For best results from the

laboratory analyses, an all glass system for the mercury analysis is

recommended.  The use of tygon tubing in the system should be minimized

or avoided: tygon has been found by the authors to absorb (and desorb)

mercury from an air stream.  Other workers have also found that both

tygon and teflon absorb mercury. ;


A simpler (less expensive and easier to clean)  bubbler could be designed

for use in firing the amalgamators.  The presently used bubbler assembly

should be reserved for the laboratory analysis procedure, which it was

originally for.

                                                                     I
The levels of SO^ encountered and the procedure of drawing it through the

pump is hard on the sampling equipment, especially the pump.  It may be
               Subcommittee D-£.21, Trace Element Task Group, Methodology
Subgroup, meeting of May 25>, 1972, private communication.

-------
necessary to disr.iantle and clean it after each run to insure dependable




operation.  It may also be necessary to make sone parts of the equipment




from corrosion-proof materials.






A larger sampling box which could hold 8-10 impingers in the ice bath




without excessive crowding would be useful and would have the advantage




that an extra scrubber or empty impinger could be inserted ahead of the




gold train if such a change was found necessary to insure cleanness of




the gold during sampling on an especially dirty stack.

-------
                                                      APPENDIX I



                                                       TABLE 9
Part A. Field Parameters:
RUN #
DATE
TIME
1972
1
10/17
4:16
pm
2
10/19
11:38
am
3
10/19
4:04
pm
4
10/20
10:S3
am
5
10/20
2:35
pm
6
10/20
4:05
pm
7
10/23
2:18
pm
SAMPLING
TIME
minutes
5.0
7.0
7.0
10.0
12.0
15.0
5.0
BAROMETRIC
PRESSURE
in. Hg



29.48
29.48
29.48
28.84
AMBIENT
TEMP.
OF
60
41
41
41
50
48.2
73.4
STACK
TEMP.
(Ts)
op
440
460
480
460
460
460
430
£so2








STATIC
PRESS.
(Ps)
in. H20
* 0.05
* 0.32
* 0.32
+ 0.04
- 0.13
-0.06
-0.41
VELOCITY
HEAD
Caps)
in. H20







ORFICE
PRESS.
(AH)
in. H20







WINGER
TEMP.
op
60
50
55
<50
67.5
56.0
60.0
DRY GAS
TEMP.
<*m)
OF
58.5
44.0
45.5
48.0
57.5
58.0
67.5
METERED
GAS VOL
(vm)
Cu. ft.
2.152
2.856
3.014
4.136
6.379
6.022
2.585
SAMPLING
RATE
CFM
.430
.407
.430
.414
.532
.401
.517

-------
RUN #
DATE
TIKE
1972
8
10/23
4:03
Dm
9
10/24
10:44
am
10
10/24
12:03
pm
11
10/24
2:20
pm
12
10/24
3.47
pm
13
10/30
10}16
ain
14
10/30
11:49
am
SAMPLING
TIME
minutes
5.0
5.0
5.0
5.0
5.0
5.0
5.0
BAROMETRIC
PRESSURE
in. Hg
28.84
29.12
29.12
29.12
29.12
29.30
29.30
AMBIENT
TEMP.
OF
62.6
50.0
44.6
45.5
45.5
46.4
50.0
STACK
TEMP.
(T8>
op
430
460
470
480
480
480
495
%so2






6.0
6.4
STATIC
PRESS.
(Ps)
in. H20
- 0.26
- 0.67
0
+ 0.36
+ 0.20
+ 0.12
- 0.10
VELOCITY
HEAD
CflPB)
in. H20







ORFICE
PRESS.
(AH)
in. H20





0.92
0.86
MPINGER
TEMP-
Op
60
50
<50
50
50
50
50
DRY GAS
TEMP.
(Tra)
op
68.0
51.5
50.5
49.0
50.0
52.0
50.0
METERED
GAS VOL.
(vm)
Cu. ft.
2.391
2.477
2.355
2.549
2.532
2.529
2.485
SAMPLING
RATE
CFM
.478
.495
,471
.510
.506
.506
.497

-------
RUN #
DATE
TIME
1972
15
10/30
2:15
cm
16
10/30
3:45
pm
17
10/31
10:17
am
18
10/31
11:39
am
19
10/31
1:50
pm
20
10/31
3:35
pm
21
11/1
1:10
pm
SAMPLING
TIME
minutes
5.0
5.0
5.0
5.0
5.0
5.0
5.0
BAROMETRIC
PRESSURE
in. Hg
29.30
29.30
29.30
29.30
29.30
29.30
29. 04
AMBIENT
TEMP.
op
52.7
50.0
46.4
48.2
50.0
46.4
56.3
STACK
TEMP.
(Ts)
°F
490
495
520
520
370
470
500
%so2

6.4
6.6




6.5
STATIC
PRESS.
(PS)
in. H^
- 0.17
0
•* 0.77
+ 0.91
* 2.75
+ 1.50
+ 0.14
VELOCITY
HEAD
(APS)
in. H20







ORFICE
PRESS.
(*H)
in. H20
0.95
0.93
0.21
0.30
1.30
1.75
2.20
IMPINGER
TEMP*
Op
50
50
50
50
50
50
50
DRY GAS
TEMP.
(Tm)
OF
53.5
54.0
46.0
49.0
51.5
49.5
60.5
METERED
GAS VOL.
(vm)
Cu. ft.
2.409
2.561
1.292
1.867
3.073
3.526
4.033
SAMPLING
RATE
CFM
.482
.512
.258
.373
.615
.705
.807

-------
RUN #
DATE
TIME
1972
22
11/1
2:42
pm
23
11/1
4:35
cm
24
11/2
10:32
am
25
11/2
12:04
pm
26
11/2
3:35
pm
27
11/2
4:45
pm
28
11/3
11:53
am
SAMPLING
TIME
minutes
5.0


5.0


5.0


5.0


5.0


5.0


5.0



BAROMETRIC
PRESSURE
in. Hg
29.04


29.04


28.85


28.85


28.85


28.85


29.06



AMBIENT
TEMP.
op
57.2


57.2


60.8


62.6


55.4


59.9


60.8



STACK
TEMP.
(Ts)
op
500


500


490


480


510


510


500



Sso2

6.4


6.8


7.2


7.0


8.1


8.3


8.0



STATIC
PRESS.
(Ps)
in. H20
+ 0.28


0


- 0.16


- 0.16


•* 1.01


+ 1.20


- 0.36



VELOCITY
HEAD
(4PS)
in. H20






















ORFICE
PRESS.
(4H)
in. H20
0.24


0.80


1.20


1.70


0.17


0.29


0.89



IMPINGER
TEMP.
Op
50


50


55


55


55


55


60



DRY GAS
TEMP.
(TJ
op
62


62


63.5


64


60


61


65



METERED
GAS VOL.
(vm)
Cu. ft.
1.465


2.495


2.982


3.499


1.054


1.551


2.620



SAMPLING
RATE
CFM
.293


.499


.596


.700


.211


.310


.524



CO
o

-------
RUN #
DATE
TIME
1972
29
11/3
2:05
pm
30
11/3
3:22
pm
31
11/8
11:10
am
32
11/8
1:36
pm
33
11/8
3:15
Dm
34
11/8
4:34
pm
35
11/9
10:25
am
SAMPLING
TIME

minutes
5.0


5.0

1.0

3.0


5.0


10.0

15.0


BAROMETRIC
PRESSURE

in. Hg
29.06


29.06

29.06

29.06


29.06


29.06

29.26


AMBIENT
TEMP.

op
57.2


53.6

44.6

47.3


46.4


47.3

44.6


STACK
TEMP.
(Ts)
op
500


510

500

500


500


510

520


#30



7.9


7.7

7.4

8.4


8.4


8.0

7.6


STATIC
PRESS.
(Ps)
in. H20
- 0.36


- 0.27

- 0.56

- 0.47


- 0.41


- 0.34

- 0.27
- 0.26
- 0.27

VELOCITY
HEAD
(4P5)
in. H20


















ORFICE
PRESS.
(4H)
in. 1^0
0.56


2.60

0.90

1.00


0.71


0.83

0.78
0.90
0.88

WINGER
TEMP*

OF
60


60

<50

<50


50


50

55
72.5
72.5

DRT GAS
TEMP.
dm)
op
60.0


60.0

46.5

48.0


49.0


50.5

46.0
48.5
51.0

METERED
GAS VOL.
(vm)
Cu. ft.
2.075


4.166

0.474

1.632


2.306


5.232

7.416


SAMPLING
RATE

CFM
.415


.833

.474

.544


.461


.523

. 494



-------
RUN #
DATE
TIME
1972
36
11/9
1:00
pm
37
11/9
3:05
pm
38
11/9
4:30
pm
39
11/10
2:42
pm
40
11/10
4:42
pm
i 41
11/13
11:33
am
42
11:13
2:36
pm
SAMPLING
TIME
minutes
20.0
15.0
20.0
20.0
20.0
15.0
10.0
BAROMETRIC
PRESSURE
in. Hg
29.26
29.26
29.26
28.90
28.90
29.04
29.04
AMBIENT
TEMP.
OF
45.5
46.4
44.6
53.6
59.0
50.0
56.3
STACK
TEMP.
(Ts)
op
525
520
520
510
520
510
510
*so2

7.6
7.6
7.7
7.5
7.5
6.6
7.2
STATIC
PRESS.
(Ps)
in. H20
- 0.14
- 0.16
- 0.24
- 0.28
- 0.33
- 0.34
- 0.36
- 0.42
- 0.41
- 0.41
- 0.43
- 0.54
- 0.52
- 0.53
- 0.55
- 0.50
- 0.52
- 0.54
- 0.55
- 0.12
- 0.06
0
- 0.34
- 0.46
VELOCITY
HEAD
UPS)
in. H20







ORFICE
PRESS.
(*H)
in. H20
0.82
0.97
0.88
0.86
0.79
0.89
0.86
0.91
0.96
0.93
0.91
0.58
0.81
0.90
0.92
0.89
0.88
0.87
0.85
0.85
0.92
0.91
1.10
1.00
IMPINGER
TEMP,
op
50
75
87.5
85
65
75
85
50
67.5
80
75
65
105
100
85
<50
50
57.5
65
<50
65
75
<50
55
ERT GAS
TEMP.
(Tm)
OF
48
52
54.5
56
50.5
54.5
57
50
53
56.5
59
55
65
72.5
77
52
54.5
56.5
58.5
44
47
50.5
45.5
47.5
METERED
GAS VOL.
(vra)
Cu. ft.
10.021
7.428
10.293
9.647
10.165
7.272
6.137
SAMPLING
RATE
CFM
.501
.495
.514
.482
.508
.485
.614
oo
ro

-------
RUN #
DATE
TIME
1972
43
11/13
4:40
jjm
44
11/14
10:36
am
45
11/14
1:16
pm
46
11/14
3:25
pm


47
11/15
12:22
pm
48
11/15
3:55
pm
SAMPLING
TIME

minutes
5.0



15.0



15.0



30.0





4.38



5.0



BAROMETRIC
PRESSURE

in. Hg
29.04



28.70



28.70



28.70





29.24



29.24



AMBIENT
TEMP.

op
57.2



44.6



42.8


—
39.2





35.6



35.6



STACK
TEMP.
(Ts)
op
510



520



520



540





575



560



£SO?



7.1



7.7



7.6



8.2





8.5



8.6



STATIC
PRESS.
(P5)
in. H20
- 0.47



- 0.38
- 0.37
- 0.36

- 0.39
- 0.34
- 0.35

- 0.36
- 0.36
- 0.36
- 0.36
- 0.32
- 0.31
- 0.25



- 0.25



VELOCITY
HEAD
CflF8)
in. H20


























ORFICE
PRESS.
(AH)
in. H20
.95-1.5



0.36
0.28
0.29

1.90
1.90
1.90

0.59
0.54
0.57
0.58
0.50
0.67
0.98



.85-. 90



IMPINGER
TEMP,

op
<50



<50
55
60

-no
100
85

50
75
75
65
55
55
<50



<50



DRY GAS
TEMP.
(TJ
OF
43.5



45.0
46.0
46.5

48.0
55.0
59.5

37.5
38.5
39
40
40.5
41.5
36



37.5



METERED
GAS VOL.
(vm)
Cu. ft.
2.617



4.579



10.652



11.592





2.140



2.376



SAMPLING
RATE

CFM
.523



.306



.710



.386





.488



.475




-------
RUN #
DATE
TIME
1972
49
11/16
10:45
am
50
11/16
1:45
pm
51
11/16
3:48
pm
52
11/17
10: 20
am
53
11/17
1:34
pm
54
11/17
3:35
pm
55
11/20
11:21
am
SAMPLING
TIME
minutes
5.0
5.0
5.0
5.0
5.0
5.0
5.0
BAROMETRIC
PRESSURE
in. Hg
29.23
29.23
29.23
29.16
29.16
29.16
29.25
AMBIENT
TEMP.
op
37.4
39.2
39.2
33.8
39.2
39.2
41.0
STACK
TEMP.
(Ts)
op
550
560
560
550
560
560
570
£so2

8.7
8.5
8.8
7.1
8.5
8.8
8.2
STATIC
PRESS.
(Ps)
in. H20
0
0
* 0.02
- 0.05
- 0.15
- 0.28
- 0.19
VELOCITY
HEAD
WP8)
in. H20







ORFICE
PRESS.
(4H)
in. #2®
0.85
0.9-1.5
1.0-1.5
0.98
>.87-0.95
1.1
0.43
3MPINGER
TEMP.
OF
<50
<50
<50
<50
<50
<50
<50
DRY GAS
TEMP.
(*»>
OF
36.5
41.0
44.5
36.0
38.0
40.0
39.5
METERED
GAS VOL.
Cm)
Cu. ft.
2.166
2.394
2.462
2.327
2.288
2.495
1.533
SAMPLING
RATE
CFM
.433
.479
.492
.465
.458
.499
.307

-------
RUN #
DATE
TIME
1972
56
11/20
2:15
pm
57
11/20
4:15
pm
58
11/21
10:27
am
59
11/21
1:30
pm
60
11/21
3:47
pm
61
11/22
10145
am
62*
11/22
2:30
pm
SAMPLING
TIME

minutes


5.0

5.0


10.0


15.0


15.0


15.0

10.0

BAROMETRIC
PRESSURE

in. Hg '


29.25

29.25


29.33


29.33


29.33


29.22

29.22

AMBIENT
TEMP.

op


41.0

41.0


38.3


37.4


39.2


37.4

36.5

STACK
TEMP.
(Ts)
op


570

570

565
560

560
560
560
570
570
570
550
550
550
560
560

%SQ





8.5

8.5


8.1


7.8


7.9


7.5

7.5

STATIC
PRESS.
(Ps)
in. H20


- 0.22

- 0.11

- 0.13
0

- 0.25
- 0.22
- 0.16
- 0.03
0
- 0.07
- 0.11
- 0.21
- 0.15
- 0.08
- 0.20

VELOCITY
HEAD
(dPs)
in. H20




















ORFICE
PRESS.
(4H)
in. H20


2.40

1.40

0.86
0.85

0.85
0.85
O.c(4
0.85
0.85
0.63
1.90
1.90
1.90

1.30

IMPINGER
TEMP*

OF


85

<50

<50
<50

<50
<50
60
<50
50
75
<50
115
85
<50
115

DRY GAS
TEMP.
(Tm)
OF


41.0

42.5

45.0
48.0

42.5
44.0
44.5
42.5
46.5
51.0
40.5
48.0
56.0
43.5
45.5

METERED
GAS VOL.
(vm)
Cu. ft.


3.609

3.146


4.899


7.240


6.861


10.738

6.404

SAMPLING
RATE

CFM


.722

.629


.490


.482


.457


.716

.572

•Pump stopped during run and had to be repaired

-------
RUN #
DATE
TIME
1972
63
12/1
4:00
pm
64
12/4
10:46
am
65
12/4
4jl5
pm
66"
12/5
11:00
am
67
12/5
4:23
pm
68
12/6
1:23
pm
69
12/7
11:00
am
SAMPLING
TIME
minutes
5.0
10.0
5.0
15.0
15.0
15.0
5.0
BAROMETRIC
PRESSURE
in. Hg
28.80
28.96
28.96
29.08
29.08
29.30
29.68
AMBIENT
TEMP.
op
41.9
42.8
42.8
50.0
50.0
28.4
23
STACK
TEMP.
(Ts)
op
520
540
540
560
540
540
540
540
540
540
475
480
485
555
?so2

7.4
7.8
8.2
8.1
8.0
9.0
-8.2
8.4
STATIC
PRESS.
(Pa)
in. H20
«• 0.11
0.32
0.19
- 0.31
- 0.37
•* 1.40
+ 0.41
VELOCITY
HEAD
WP8)
in. H20
0.53
0.53
0.54
0.57
0.59
0.58
0.57
0.57
0.57
0.57
0.49
0.49
0.64
0.50
ORFICE
PRESS.
(AH)
in. H20
1.60
0.98
1.05
0.94
1.20
1.20
1.30
1.55
1.60
1.60
2.20
2.20
2.25
2.3-2.8
IMPINGER
TEMP.
Of
50
<50
60
<50
<50
<50
<50
<50
<50
<50
<50
<50
<50
55
DRY GAS
TEMP.
(T»)
OF
48.5
41.0
44.5
44.0
51.5
55.5
58.0
62.5
67.0
70.0
31.5
34.0
35.0
39.0
METERED
GAS VOL.
(Vm>
Cu. ft.
3,156
4.897
2.311
7.830
8.838
10.406
3.816
SAMPLING
RATE
CFM
.631
.490
.462
.522
.589
.694
.763

-------
RUN #
DATE
TIME
1972
70
12/7
4:21
pm
71
12/11
11:38
am
72
12/11
4:03
pm

SAMPLING
TIME
minutes
15.0
15.0
15.0

BAROMETRIC
PRESSURE
in. Hg
29.55
29.61
29.60

AMBIENT
TEMP.
op
28.4
23.0
25.7

STACK
TEMP.
(TS)
op
570
570
570
580
580
580
580
580
580

£S02

7.4
8.2
8.2

STATIC
PRESS.
(Ps)
in. H20
+ 0.32
+ 0.13
- 0.58

VELOCITY
HEAD
WPB)
in. H20
0.54
0.55
0.54
0.54
0.53
0.53
0.51
0.51
0.52

ORFICE
PRESS.
(*H)
in. H20
0.42
0.41
0.41
0.31
0.29
0.29
1.04
1.05
1.05

BIPINGER
TEMP.
op
<50
<50
<50
<50
. <50
<50
<50
<50
<50

DRY GAS
TEMP.
(*m)
op
33.0
36.0
36.5
29.0
32.5
35.5
31.5
35.0
38.5

METERED
GAS VOL.
(vj
Cu. ft.
4.742
4.215
6.923

SAMPLING
RATE
CFM
.316
.281
.462




OD

-------
Part B.  Laboratory Parameters:
RUN
#
1
2
3
4
5
6
7
PARTICULATES
PROBE AND
CYCLONE
.»g

1.56
0.28
0.09
0.15
0.24

FILTER
jag







TOTAL
-»g









A

H
H
2.8
S
3.0
H
H
H
E
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
A
2.24
57.4%
A
4.08
96.7%
A
5.02
85%
A
1.7
24.4%
A
1.6
47.0%
A
5.0
72.6%
B
C
A
0.66
16.9%
A
0.10
2.4%
A
0.60
10.2%
A
4.30
61.7%
A
1.12
33%
A
0.56
8.1%
A
2.04
45.5%
D
A
1.0
25.6%
A
<.04
<1%
A
0.28
4.8%
A
0.96
13.8%
A
0.68
20.0%
A
1.32
19.2%
A
2.16
48.23!
E
K
K
<.28
K
K
K
K
0.10
A
0.28
6.2%
F
SG
SG
SG
K
0.25
K
1.3
K
0.50
K
0.70
G



SG
SG
SG
SG
H







TOTAL
Hg

Jig
3.90
8.86
96.8%
9.18
7.30
4.85
7.72
92.2%
5.18
86.5%
Hg
CONCENTRATION
Jig/CF
1.81
3.10
3.04
1.76
0.76
1.28
2.00
^g/1
0.064
0.110
0.108
0.062
0.027
0.045
0.071
                                                                                                                       CD
                                                                                                                       CO

-------
RUN
#
8
9
10
11
12
13
14
PARTICULATES
PROBE AND
CYCLONE
Jag





0.56
0.53
FILTER
-»g







TOTAL
-»g









L

H
2.08
S
0.44
H-S
0.48
E
E
A
1.24
28.1%
H
0.77
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IK EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
E
E
E
E
A
3.0
81.5%
A
1.42
32.2%
E
C
A
2.52
68.1%
A
0.92
67.6%
A
0.28
4.8%
A
3.70
86.9%
A
0.40
10.9%
A
1.76
39.8%
A
1.40
34.1%
D
A
1.16
31.3%
A
0.20
14.7%
A
0.56
9.6%
A
0.32
7.5%
A
0.28
7.6%
E
A
0.60
14.63
E
A
0.02
0.5%
A
0.24
17.6%
A
5.00
85.6%
A
0.24
5.6%
E
E
A
2.10
51.2%
F
K
0.37
K
0.55
K
0.20
K
0.59
K
1.73
K
0.42
K
0.67
G
SG
SG
SG
SG
SG
SG
SG
H







TOTAL
Hg

jug
6.15
94.0%
2.35
76.6%
6.52
96.9%
4.85
87.8%
5.41
68.0%
5.40
92.2%
6.07
89.0%
Hg
CONCENTRATION
Jig/CF
2.57
0.95
2.77
1.90
2.14
2.14
2.44
^g/1
0.091
0.034
0.098
0.067
0.075
0.075
0.086
00

-------
RON
#
15
16
17
18
19
20
21
PARTICULATES
PROBE AND
CYCLONE
J*g
0.95
0.55
0.25
0.31
0.09
0.43
0.81
FILTER
.Mg







TOTAL
-»g









A

S
0.25
H-S
0.31
H
0.25
H
1.50
H
0.30
H
1.03
H
1.86
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
B
B
E
E
E
0,60
E
0.34
E
0.19
C
A
1.70
23.6%
A
1.52
21.6%
A
3.70
90.9%
A
0.44
30.6%
A
0.18
58.0%
A
0.80
45.5%
A
2.75
44.1%
D
A
3.15
43.5%
A
0.90
12.8%
A
0.29
7.1%
A
0.84
58.3%
A
0.07
22.6%
A
0.68
38.6%
A
3.10
49.7?!
E
A
2.40
33.1%
A
4.60
65.5%
A
0.08
2.0%
A
0.16
11.1%
A
0.06
19.4%
A
0.28
15.9%
A
0.38
6.0%
F
K
0.12
K
0.15
K
0.48
K
1.20
K
0.18
K
0.68
K
1.29
G
SG
SG
SG
SG
SG
SG
SG
H







TOTAL
Hg

Jig
8.57
98 . 6%
8.03
98.1%
5.05
90.5%
4.45
73.0%
1.48
87.8%
4.24
84.0%
10.38
87.6%
Hg
CONCENTRATION
^Jig/CF
3.56
3.14
3.91
2.38
0.48
1.20
2.57
^g/1
0.125
0.111
0.138
0.084
0.017
0.042
0.091

-------
RUN
*
22
23
24
25
26
27
28
PARTICULATES
PROBE AHD
CYCLONE
Jig
0.30
0.46
0.43
0.31
0.09
0.05
1.49
FILTER
-»g







TOTAL
Jig









A

H
0.61
H
1.39
H
2.20
H
2.08
H
0.52
H
1.58
H
2.57
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
E
0.30
E
0.36
E
0.69
B
0.36
B
0.20
E
0.42
E
1.01
C
A
1.70
78%
A
1.71
60.0%
A
3.65
93.8%
A
1.85
33.1%
A
1.28
51.6%
A
0.88
24.7%
A
0.84
46.1%
D
A
0.28
12.8%
A
0.59
20.7%
A
0.19
4.9%
A
3.50
62.5%
A
0.44
17.7%
A
1.40
39.3%
A
0.88
48.4%
E
A
0.20
9.2%
A
0.55
19.3%
A
0.05
1.3%
A
0.24
4.3%
A
0.76
30.6%
A
1.28
36.0%
A
0.10
5.5%
F
K
0.48
K
1.63
K
1.16
K
0.44
K
0.69
K
0.17
K
1.57
G
SG
SG
SG
SG
SG
SG
SG
H







TOTAL
Hg

jag
3.87
87 . 6%
6.69
75.6%
8.37
86.1%
8.78
95.0%
3.98
82.7%
5.78
97.0%
8.46
81.4%
Hg
CONCENTRATION
Jig/CF
2.64
2.68
2.81
2.51
3.78
3.73
3.23
^g/1
0.093
0.095
0.099
0.089
0.133
0.132
0.114

-------
RUN
#
29
30
31
32
33
34
35
PARTICULATES
PROBE AND
CYCLONE
.Mg
1.65
1.77
0.08
0.13
0.70
1.45
2.75
FILTER
Jag







TOTAL
-»g









A

H
1.29
H
3.09
H
0.20
H
0.10
H
1.10
H
0.05
H
1.18
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
E
0.19
E
0.34
E
0.05
E
0.17
B
0.28
E
0.15
B
0.51
C
A
3.50
85.4%
A
2.06
62.4%
A
0.10
40.0%
A
0.26
57.7%
A
0.40
50.0%
A
0.22
57.9%
A
3.55
66.8%
D
A
0.36
8.8%
A
0.74
22.4%
A
0.08
32.0%
A
0.10
22.2%
A
0.22
27.5%
A
0.10
26.3%
A
0.88
16.6%
E
A
0.24
5.8%
A
0.50
15.1%
A
0.07
28.0%
A
0.09
20.0%
A
0.18
22.5%
A
0.06
15.8%
A
0.88
16.6%
F
K
0.25
K
0.47
K
1.41
K
1.25
K
3.90
K(15g)
2.00
K(20g)
3.54
G
SG
SG
SG
SG
SG
SG
SG
H







TOTAL
Hg

•»g
7.48
96.7%
8.97
94.8%
1.99
29.1%
2.10
40.5%
6.78
42. S%
4.03
50.4%
13.29
73.4%
Hg
CONCENTRATION
.Jig/CF
3.60
2.15
4.20
1.29
2.94
0.77
1.79
>»gA
0.127
0.076
0.148
0.045
0.104
0.027
0.063
ro

-------
RUH
#
36
37
38
39
40
41
42
PARTICULATES
PROBE AND
CYCLONE
J»g
3.00
2.03
1.88
1.56
1.51
0.45
0.70
FILTER
J*g







TOTAL
Jig









A

H
2.92
H
2.63
H
4.46
H
4.58
H
2.24
A
1.36
(1.04)
15.3%
A
1.91
(0.97)
24.3%
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
E
0.33
E
0.26
E E
0.18
E
0.48
H
0.19
;GS TIP)
A
3.16
(0.04)
35 . 6%
A
1.86
(0.16)
23.6%
C
A
3.85
55.0%
A(33g)
2.25
44.2%
A(33g)
1.74
34.0%,
E(gwf
0.11
E
0.07
A
2.46
(0.02)
27.7%
A
1.91
(0.04)
24.3%
D
A
1.20
17.2%
A(33g
1.48
29.1%
A(33g)
2.04
39.8%
A(33g
2.13
49.7%
A(33g)
0.74
59.6%
A
0.96
(0.03)
10.8%
A
1.04
(0)
13.2%
E
A
1.94
27.8%
A(33g)
1.36
26.7%
A(33g)
1.34
26.2%
A(33g)
2.15
50.2%
A(33g)
0.50
40.3%
A
0.94
(0.03)
10.6%
A
1.14
(0.02)
14.5%
F
K(33g)
8.44
K(25g)
4.61
K(33g>
5.50
K(34g)
8.49
K(34g)
9.13
K(27g)
4.16
K(16g)
0.72
G
SG
SG
SG
SG
SG
SG
SG
H







TOTAL
Hg

Jttg
21.68
61.1%
14.62
68.5%
17.14
67.9%
19.50
56.5%
14.38
3fi.S*
14.65
71.6%
10.47
93.1%
Hg
CONCENTRATION
^ig/CF
2.16
1.97
1.66
2.02
1.41
2.01
1.71
^gA
0.076
0.069
0.059
0.071
0.050
0.071
0.060
*A 4  cm  column of glass wool was packed  in "C."  This increased pressure drop in the
that the pump was at maximum vacuum throughout the run.
train so much

-------
RUN
t





43



44



45



46



47




48

PARTICULATES


PROBE AND
CYCLONE

jag

0.44



0.35



1.60



1.68



0.74




0.43


FILTER


jag

























TOTAL


-Ug
























TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS

A

A
2.04

68.9%
A
6.96
(1.55)
63.8%
A
1.13
(1.93)
11.2%
A
7.18
(3.59)
57.5%
A
3.39
(0.51)
62.1%
A
1.63
(0.04)
32.0%
B

A
0.44

14.9%
A
2.06
(0)
18.9%
A
2.48
(0.27)
24.5%
A
2.08
(0.11)
16.7%
A
0.62
(0)
11.4%
A
1.82
(0.41)
35.7%
C

A
0.20

6.8%
A
0.50
(0)
4.6%
A
3.68
(0.04)
36.4%
A
1.18
(0.05)
9.4%
A
0.66
(0)
12.1%
A
0.68
(0.05)
13.4%
D

A
0.12

4.0%
A
0.88
(0)
8.1%
A
1.38
(0)
13.6%
A
1.14
(0)
9.1%
A
0.36
(0)
6.6%
A
0.44
(0.05)
8.7%
E

A
0.16

5.4%
A
0.51
(0)
4.7%
A
1.44
(0)
14.2%
A
0.90
(0.09)
7.2%
A
0.42
(0)
7.7%
A
0.50
(0)
10.2%
F

K
2.76


K(25g)
2.80


K(55g)
7.04


K(63g)
8.88


K
9.93


K(15.5g
1.58


Q

SG



SG



SG



SG



K(3%)
3.64


K(3%)
2.98


H

















SG



SG




TOTAL
Hg


jag

6.16

55.2%

15.61

82.1%

20.99

66.5%

26.88

67.0%

20.27

33.0%

10.63

57.1%

Hg
CONCENTRATION


^ig/CF


2.35



3.41



1.97



2.32



9.47



4.47

^g/1


0.083



0.120



0.070



0.082



0.334



0.158


-------
RUN
#
49
50
51
52
53
54
55
PARTICULATES
PROBE AND
CYCLONE
Jig
0.50
0.45
0.24
0.44
0.42
0.28
0.56
FILTER
Jig
0.62
(0.0364g
0.72
(0.0330i
0.82
(0.0229{
0.60
0.0639g
0.32
;0.0477g
0.58
0.0289g
0.40
0.0165g
TOTAL
Jig
1.12
)
1.17
)
1.06
)
1.04
0.74
0.86
0.96


&
A(24g)
6.10
(0.35)
92.2%
A(24g)
3.48
(0.45)
64.0%
A(24g)
3.06
(1.02)
47.9%
H
2.41
H
2.04
H
1.51
H
1.52
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IK AMALGAMATORS
B
A(24g)
0.35
(0)
5.3%
A(24g)
0.50
(0.02)
9.2%
A(24g)
1.40
(0.02)
21.9%
E
0.38
E
0.05
E
0.04
E
0.03
C
A(24g)
0.04
(0)
0.6%
A(24g)
1.20
(0)
22.0%
A(24g)
0.16
(0.02)
2.5%
A
6.40
(.02)
94.4%
A
5.20
(0)
94.8%
A
0.60
(.02)
41.6%
A
4.98
(0)
88.6%
D
A(24g)
0.08
(0)
1.2%
A(24g)
0.10
(0)
1.8%
A(24g)
1.44
(0)
22.6%
A
0.22
(0)
3.2%
A
0.12
(0)
2.2%
A
0.48
(0.09)
33.3%
A
0.32
(0.045
5.7%
E
A(24g)
0.04
(0)
0.6%
A(24g)
0.16
(0)
2.9%
A(24g)
0.32
(0)
5.0%
A
0.16
(0.32)
2.4%
A
0.16
(0)
2.9%
A
0.36
(0.01)
25%
A
0.32
(0)
5.7%
F
K(15g)
10.45
K(20g)
3.99
K(25g)
3.45
K
0.15
K(15g)
0.28
K(15g)
2.99
K
0.23
G
K(10g)
0.46
K(10g)
2.40
K(3%)
1.30
K
0.60
K
0.08
K
1.73
K
0.03
H
SG
SG
SG
SG
SG
SG
SG
TOTAL
Hg

Jig
18.99
42.5%
13.47
52.6%
13.25
64.2%
11.70
93.6%
8.67
95.8%
8.69
45.7%
8.43
96.9%
Hg
CONCENTRATION
Jig/CF
8.77
5.63
5.38
5.03
3.79
3.48
5.50
jigA
0.310
0.199
0.190
0.178
0.134
0.123
0.194
\A

-------
RUN
#
56
57
58
59
60
61
62
PARTICULATES
PROBE AND
CYCLONE
Jig
0.05
0.77
0.88
0.68
1.15
2.80
0.45
FILTER
Jig
0.56
(0.0231g
0.48
(0.0393s
0.92
(0.0972g
0.96
(0.1360g
2.48
(0.1421g
1.14
0.1590g)
0.94
(0.1756§
TOTAL
Jig
0.61
1.25
1.80
1.64
3.63
3.94
1.39


A

H
3.36
H
2.40
H
5.40
H
5.32
H
3.15
H
1.58
H
2.89
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
£
0.12
B
0.45
B
0.07
B
0.10
B
0.11
B
0.10
B
0.12
C
A
11.98
(0)
92.3%
A
10.18
(0)
90.7%
A
12.00
(0)
93.3%
A
16.80
(0.03)
91.3%
A
13.80
(0)
67.6%
A
6.63
(0)
59.3%
A
10.75
(0.03)
74.4%
D
A
0.74
(0)
5.7%
A
0.86
(0)
7.7%
A
0.70
(0)
5.4%
A
1.08
(0)
5.9%
A
5.10
(0)
25.0%
A
3.55
(0.05)
31.8%
A
3.1
(0)
21.4%
E
A
0.26
(0)
2.0%
A
0.18
(0.42)
1.6%
A
0.16
(0)
1.2%
A
0.52
(0)
2.8%
A
1.5
(0)
7.4%
A
1.00
(0.04)
8.9%
A
0.60
(0)
4.2%
F
K(25g)
0.22
K(25g)
0.13
C(30g)
0.44
K(45g)
1.15
K(50g)
1.30
K(80g)
1.08
K(68g)
1.58
G
K
0.38
K
0.03
K
0.06
K(10g)
0.33
K(15g)
D.10
K(23g)
0.57
K(20g)
0.72
H
SG
SG
SG
SG
SG
SG
SG
TOTAL
Hg

Jig
17.67
96.6%
15.90
99.0%
20.63
97.6%
26.97
94.5%
28.69
95.1%
18.54
91.1%
21.18
89.1%
Hg
CONCENTRATION
Jig/CF
4.90
5.05
4.21
3.72
4.18
1.73
3.31
^gA
0.173
0.178
0.149
0.132
0.148
0.061
0.117

-------
RUN
#
63
64
65
66
67
68
69
PARTICUIATES
PROBE AMD
CYCLONE
^g
0.33
0.34
0.09
0.32
0.66
2.17
0.22
FILTER
jag
0.24
(0.0757E
0.38
(0.0813g
3.46
(0.0469g
1.06
(0.0517g
0.52
0.0481g
0.91
0.0865g
0.30
0.0903g
TOTAL
-»g
0.57
)
0.72
i
3.55 ~
)
1.38
)
1.18
3.08
0.52


&
H
3.51
H
8.90
H
0.63
H
14.49
H
16.45
H
3.97
H
5.52
TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
E
0.13
E
0.11
E
0.19
E
0.09
E
0.17
E
0.06
E
0.11
C
A(30g)
6.70
(0.23)
76.1%
A(30g)
5.16
(0.02)
86.7%
A(30g)
3.16
(0.01)
82.1%
A(30g)
22.47
(0.02)
98.7%
A(30g)
21.98
(0.04)
97.1%
A(30g)
32.73
(0.01)
89.0%
A(30g)
5.78
(0.01)
84.8%
D
A(30g)
0.10
(0)
1.1%
A(30g)
0.19
(0.01)
3.2%
A(30g)
0
(0)
0%
A(30g)
0.05
(0.01)
0.2%
A(30g)
0.22
(0.03)
1.0%
A(30g)
3.78
(0.01)
10.3%
A(30g)
0.94
(0.02)
13.8%
£
A(30g)
0.06
(0.04)
0.7%
A(30g)
0.21
(0)
3.5%
A(30g)
0
(0)
0%
A(30g)
0.03
(0.02)
0.1%
A(30g)
0.14
(0.03)
0.6%
A(30g)
0.13
(0.01)
0.4%
A(30g)
0.04
(0.02)
0.6%
F
A(30g)
0.04
(0)
0.4%
A(30g)
0.20
(0.26)
3.4%
A(30g)
0.12
(0.0.1)
3.1%
A(30g)
0
(0.02)
C%
A(30g)
0.14
(0.03)
0.6%
A(30g)
0.12
(0.01)
0.3%
A(30g)
0.06
(0.02)
0.9%
G
A(30g)
1.90
(0)
21.6%
A(30g)
0.19
(0)
3.2%
A(30g)
0.57
(0.02)
14.8%
A(30g)
0.22
(0.04)
1.0%
A(30g)
0.16
(0.03)
0.7%
SG
K(20g)
0
H
K(20g)
<0.04
SG
K(20g)
0.10
SG
SG

SG
TOTAL
Hg

-»g
13.32
99.7%
15.97
8.36
98.8%
38.84
40.60
43.91
13.04
1001
Hg
CONCENTRATION
^ig/CF
4.22
3.26
3.62
4.96
4.59
4.22
3.42
^g/1
0.149
0.115
0.128
0.175
0.162
0.149
0.121

-------
RUN
#
70
71
72

PARTICULATES
PROBE AND
CTCLONE
J*g
0.15
0.08
0.07

FILTER
Jig
7.76*
(O.OSOOg
0.64
(0.0359g
0.54
(0.0493g

TOTAL
-ug
7.91
)
0.72
i
0.61
>



&

H
1.69
H
11.14
H
13.78

TRAIN CONFIGURATION
MICROGRAMS OF Hg FOUND IN EACH POSITION
PERCENTAGE DISTRIBUTION OF Hg IN AMALGAMATORS
B
E
0.04
E
0.14
B
0.09

c
A(30g)
1.63
(0.02)
79.17.
A(30g)
4.99
(0.04)
61.5%
A(30g)
9.24
(0.03)
79.4%

D
A(30g)
0.34
(0.02)
16.5%
A(30g)
0.77
(0.03)
9.5%
A(30g)
1.43
(0.02)
12.3%

E
A(30g)
0.05
(0.02)
2.4%
A(30g)
0.85
(0.02)
10.5%
A(30g)
0.33
(0.01)
2.8%

F
A(30g)
0.04
(0.02)
1.9%
A(30g)
0.87
(0.01)
10.7%
A(30g)
0.35
(0.02)
3.0%

Q
K(25g)
0.20
A(30g)
0.63
(0.02)
7.8%
A(30g)
0.29
(0.05)
2.5%

H
SG
SG
SG

TOTAL
Hg
Jig
11.98
98.3%
20.23
26.25

Hg
CONCENTRATION
Jig/CF
2.53
4.80
3.79

^g/1
0.089
0.169
0.134

*The filter became wet during  this  run.

-------
                        APPENDIX II



RECOMMENDED PROCEDURE


The following is an outline of the recommended procedure as determined

in this study, for the analysis of mercury in stack gases of high SOg

content.


1- Apparatus and Reagents


In addition to the equipment normally used for isokinetic particulate

sampling (glass lined probe, weighed filter, filter holder, cyclone,

sample box, console with pump, etc.) the following items are required.


a- For Sampling and Cleanup Procedure:

      1- Apparatus

            Leco induction furnace equipped with a variac

            Tank of nitrogen gas equipped with a pressure reducing
            valve, flow meter and a drying tube packed with magnesium
            perchlorate.

            Bubbler apparatus with at least five interchangeable
            sample holders

            Two female ball joint adapters to fit amalgamators

            Two ball joint clamps

            Three impimgers - two modified and one Greenburg-Smith

            Five amalgamators and "shells"

            Gold chips, about 1/16 inch square by 0.007 inch thick,,
            1$0 grams required for each run.  These should have
            been fired in a refractory oven at about 600-700°C for a
            few hours (or overnight) before each run.

            Sample containers - 6 oz. and 16 oz. wide mouth jars
            with lids.
                                99

-------
                                                               100


            Sample containers for filters - plastic Petri dishes

            Graduated cyclinders - 2£, %
-------
                                                               101


            Laboratory Data Control Mercury Monitor  (or a standard
            atomic  absorption unit equipped for flameless determinations)

            0-10 nrv recorder

            Bubbler apparatus with interchangeable sample holders

            Drying  tube

            Tygon tubing

            Syringes - 5 and 10 ml.


      2- Reagents

            Standard mercury solutions

                (A)  Stock 1000 ppm mercury standard containing ~L%
                     concentrated nitric acid

                (B)  1  ppm mercury standard containing 1/6 concentrated
                     nitric  acid prepared fresh weekly

                (C)  f>0 ppb  mercury standard containing 1% concentrated
                     nitric  acid prepared fresh daily

            Stannous chloride solution: mix 200 gram SnCl2*2 HoO with
            £00 ml  HC1 and  dilute to 1 liter with distilled water.

            Hydroxylamine hydrochloride solution: dissolve $0 gram
            NH2OH-HC1  into  £00 ml of distilled water.

            Magnesium  perchlorate

            Distilled  water


2- Preparation of the  Amalgamators

The amalgamators are prepared as follows.  A small plug of quartz wool is

inserted from the top  of the  amalgamator tube and pushed into place against

the supporting  indentations.  A length of \ inch dowel rod and a piece of

stiff wire can be used to help wedge the wool into position.  The gold chips

are removed from the oven and allowed to cool for at least £ minutes.  The

gold chips are then weighed out and about 30 grains of chips poured into each

amalgamator using the  plastic funnel.  The amalgamator may be tapped gently

-------
                                                              102


to help settle the chips against the plug.  After filling the amalgamator

tubes with the gold chips, the ground glass tapers should be greased

and the amalgamator tubes placed in the "shells."  If the amalgamators

are not to be assembled into the train immediately, the ends should be

stoppered as a precaution against contamination.


3- Assembly of the Sampling Train

All glassware should be rinsed before use with the following sequence:

1£ SnCl2 in 2.$% HC1, 1:3 HNO-j-HgO, distilled water and acetone.  The

glassware should be allowed to dry before placing it into the train.


The probe, cyclone and filter are assembled into the sampling box in the

same configuration ordinarily used for taking an isokinetic particulate

sample.  The impinger and amalgamator sequence is then assembled as

follows, starting with the filter:

            a) A Greenburg-Smith impinger containing 2^0 ml of distilled
               water.

            b) An empty impinger

            c) Five amalgamators in series, each one containing 30 grams
               of gold chips.

            d) An impinger containing about 2|?0 grams of silica gel.

Each impinger and amalgamator should be labeled with the run number and

the position of that unit in the train (e.g. 13-C).  The configuration

of the recommended sampling train (excluding cyclone) is illustrated in

Figure 20.


It- Sampling

After assembling the train a leak check should be performed and the

sample box filled with ice and water.  From this point on the sampling

-------
                                                                               103
pilot Tube
                Heated, Filter
        Silica  Gel
                                                                 Thermometer
                                                                .Check Valve
                                                              Vacuum Line
      Greenburg-Smith Impinger /
      Scrubber  Solution
                            /
                Modified  Impinger
                Empty
    \\^
    s\\\\\
Modified Implngers
Gold Amalgamators
    Figure 20.  Configuration of the Recommended Sampling Train (excluding cyclone).

-------
                                                                  ioU


procedure and the sample data recorded is the same as for the normal

isokinetic procedure as used for particulate sampling.  The sample is

taken isokinetically for 15 minutes.


5- Cleanup Procedure

After obtaining the sample, the probe and sample box are taken to a

suitable area for the cleanup procedure.  Distilled water is used for

all rinses.  Samples are taken from each part of the train ahead of

the silica gel and placed in appropriately labeled sample containers

as follows:

           a)  The probe, cyclone and the glass parts of the filter
               assembly are rinsed into a 16 oz. jar containing 25 ml
               of the 3/6 KMnO,  solution.

           b)  The filter (previously weighed)  is placed in a suitable
               container which is marked with the run number.

           c)  The inside part of the first impinger (Position A) and
               the right angle connector leading into it are rinsed
               into the contents of the irapinger "shell".  About 7 grams
               of solid KMnO,  are then added slowly, with stirring, to
               the liquid inuthe "shell" until the violet color of the
               permanganate persists.  The solution is then transferred
               to a 16 oz. sample container and the grams of added
               potassium permanganate are recorded.

           d)  The empty impinger- and the connector leading into it
               are rinsed into a 6 oz. sample jar containing 25 ml of
               the 3$ KMnOr solution.

           e)  Each of the amalgamator "shells" and the connector leading
               into that amalgamator are rinsed into separate 6 oz. sample
               jars, each containing 25 ml of the Jk KMnO^ solution.

           f)  Each amalgamator is fired into 50 ml of the 3? KMnOr solution
               using the apparatus shown in Figure l5«  The amalgamators
               are fired in reverse of their order in the train (i.e. the
               last one is fired first, the next to the last one is fired
               second, etc.) in order to minimize contamination of suc-
               cessive samples.  The amalgamator is centered in the coil
               of the induction furnace and connected to the nitrogen

-------
                                                               105


               supply and the bubbler with two female ball-joint adapters
               and two clamps.  The nitrogen flow is set at 0.5 liters per
               minute.  The firing is commenced with the variac at a
               setting of 60/6 and increased by 5? each minute until the
               gold is glowing over its entire length.  After firing each
               amalgamator, the sample tube is detached, the drops of
               permanganate clinging to the bubbler tube are rinsed into
               it and then the contents of the sample tube are rinsed
               quantitatively into a 6 oz. sample container.  After
               firing the series of amalgamators, the bubbler apparatus
               and all the sample tubes are rinsed using tfte rinse
               sequence described previously.  If any tygon tubing is
               used between tne amalgamator and tne bubbler, it should
               be kept as short as possible and then replaced for each run.

           g)  A 50 ml blank of the 3$ permanganate solution is taken
               for each run, placed in a 6 oz. sample container and
               sent to the laboratory along with the samples.


A field record should be kept of all data recorded during the run

and of each sample taken for analysis from the train.  Upon receipt

in the laboratory, each of the samples from the train is diluted to

the appropriate volume in a volumetric flask just prior to analysis.


6- Analysis of the Samples

a- Permanganate Solutions

A standard curve is prepared in duplicate for 0.05, 0.10, 0.25, 0.50,

and 0.75 M-g mercury standards by diluting 1, 2, 5, 10, and 15 ml aliquots

of the standard 50 ppb mercury solution to 50 ml.  Each sjtandard is

placed in an interchangeable sample tube and attached to the bubbler.

Three ml of the stannous chloride solution is added with a syringe

through the ampoule stopper using sufficient force to mix the solution

with the standard.  The sample is then aerated ( l.U liter/minute air),

volatilizing the mercury which is carried through a drying tube filled

with magnesium perchlorate and then through the mercury monitor operated

at a 0.6k range setting (least sensitive).

-------
                                                              106


The permanganate samples which contain the mercury from the amalgam-

ators are diluted to 100 ml with distilled water and returned to their

containers.  (Great care must be taken to rinse the volumetrics with

stannous chloride solution between dilutions or cross contamination

is observed.)  The wash and scrubber solutions are analyzed at the strength

at which they arrive from the sampling site.  Before each aliquot of

sample solution is removed from a jar, the container is shaken thoroughly

until all solids are evenly dispersed in the solution.  An appropriate

sized sample is quickly pipetted from the jar and placed in an inter-

changeable sample tube where it is diluted to approximately J>0 ml with

distilled water.  Three ml of hydroxylamine hydrochloride solution is

added and the tube is swirled until the permanganate color disappears.

The tube is then attached to the bubbler and the solution is reduced

with three ml of the stannous chloride solution.  The mercury is then

volatilized by aerating the solution (l.li liter/minute air).  The revol-

atilized mercury is carried by the air stream through the mercury monitor.

All samples should be run in duplicate.  The concentrations are calculated

from the standard curve and the amount of mercury in each sample is calcul-

ated from the dilution factor and the size of the aliquot.


b- Filters

One half of the filter is boiled in 10 ml of concentrated nitric acid

for 10 minutes.  The filter is disintegrated with a high pressure stream

of distilled water and the mixture is diluted to 100 ml.  After cooling,
                                                                   i
the solutions are analyzed by placing 50 ml aliquots in the interchange-

able sample tubes and following the sample procedure as is used for

-------
                                                                   107





standard solutions.






7- Analysis of the Data




The total amount of mercury found and its distribution in the sample




train is obtained from the data determined in the laboratory.  This




information may conveniently be organized on a data form such as the



one shown in Figure 21.
The ratios of t2/tj_, t./tp, etc. may be calculated for those amalgam-



ators showing sufficient mercury to give a valid value for the ratio.




These values may then be compared to give an estimate of the extent of




gold contamination occuring during the sampling process.  In the absence




of such contamination the ratio tjj/t^^ should be about 0.1 or less.




In addition the percentage of the total "amalgamator mercury" found on




each amalgamator should show an orderly decrease through the train and




the percentage found on the last one or two amalgamators should be only




one or two percent of the whole (or about the same value as the blank).



If these criteria are satisfied, then a collection efficiency of at least




    may be assumed.

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Figure 21.  Laboratory Data Form
SAMPLE
NUMBER


















HILLILITERS
TAKEN FOR
ANALYSIS


















TOTAL VOLUME


















MICROGRAMS
MERCURI FOUND


















TOTAL
MICROGRAMS
OF MERCURY


















BLANK CORE.


















NET TOTAL
MICROGRAMS
OF MERCURY


















COMMENTS














	 LJ
b



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                                                109
         APPENDIX III
Isokinetic Data Sheets, Run  72

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                                                                      TIELD DATA
                      PLANT.
                      DATE_
                                                                           PROBE LENGTH AND TYPE
                                                                           NOZZLE I.D
                      SAWPUNG LOCATION  C^jSo
                      SAMPLE TYPE   /Merc fry
                      RUN NUMBER        "7^
                      OPERATOR  Ra-ldvik J-  -S
AMBIENT TEMPERATURE	'.
BAROMETRIC PRESSURE	7=1
STATIC PRESSURE, (P )	ni
FILTER NUMBER (s)	
ASSUMED MOISTURE,»,.
SAMPLE BOX NUMBER.
METER BOX NUMBER _
METER AHg
C FACTOR	• 97
                                                              SCHEMATIC OF TRAVERSE POINT LAYOUT
                                                                                                             	
                                                                                                 PROBE HEATER SETTING   too %
                                                                                                 HEATER BOX SETTING,     3OQ °F
                                                                                                 REFERENCE ap_	
                                                        READ AND RECORD ALL DATA EVERY.
                                                                      MINUTES
TPllfrPCn
1 l\nVC.IVJL
DHtUT^
nUlM
fciminfa
'IIUIIIULU
3amp|jna
Time.0
fS~ /w i n






















\. CLOCK TIME
"T^XrX
TIME, mm ^v
"
s-n^r V:^>3
VIcJ?
v : 12
5r0p V:/*
/


















GAS METER READING

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                                                                        Ill
                         NOMOGRAPH DATA
 PLANT.

 DATE_
 SAMPLING LOCATION.
      72_
	 r
CALIBRATED PRESSURE DIFFERENTIAL ACROSS
ORIFICE, in. H20
AVERAGE METER TEMPERATURE (AMBIENT + 20 °F),°F
PERCENT MOISTURE IN GAS STREAM BY VOLUME
BAROMETRIC PRESSURE AT METER, in. Hg
STATIC PRESSURE IN STACK, in. Hg
(Pm±0.073 x STACK GAUGE PRESSURE in in. H20)
RATIO OF STATIC PRESSURE TO METER PRESSURE
AVERAGE STACK TEMPERATURE, °F
AVERAGE VELOCITY HEAD, in. H20
MAXIMUM VELOCITY HEAD, in. H20
C FACTOR
CALCULATED NOZZLE DIAMETER, in.
ACTUAL NOZZLE DIAMETER, in.
REFERENCE Ap, in. H20
AH@
Tmavg.
Bwo
pm
ps
PVPm
savg.
APavg.
APmax.
I.&?
LfS0
J"
T-^to
-.or
.^3%
J~?o
.S~l

, <77

. zr

EPA (Dur) 234
   4/72
U. =. GOVERNMENT PRINTING OFFICE: 1973	746769/4162

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