Ferrous Sulfate Supply Chain - Executive Summary

Ferrous Sulfate

Direct Use Chemical p-ecursor Chemical

(liquid, solid)

Inputs to Manufacturing Process:
Sulfuric Acid Iron Oxides


Derivative Water Treatment Chemicals:

Ferric Sulfate

^ % of Total Domestic Consumption
Attributed to Water Sector:
Approximately 30%

fos Understanding Chemical Supply Chains
Map of Suppliers & Manufacturers

Product Family:



CAS No.: 7720-78-7

2 Shelf Life:
12+ Months



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Production of ferrous sulfate
depends on the steel industry
and production of sulfuric acid
to produce manufacturing in-
puts. Fluctuations in demand in
the steel industry may impact
production and price of ferrous


Criticality: High. Essential for
coagulation and production of
water treatment chemicals.

Likelihood: Low. Previous price
increases, but no supply disrup-

Vulnerability: Low. Distributed
domestic manufacturing and


Iron Oxides


Ferrous Sulfate

Sulfuric Acid


End Use

Water Treatment Applications


	Water treatment chemical production

Other Applications


Animal feed


Iron fortification of foods


Domestic Manufacturing Locations (2015):
13, distributed throughout the U.S.

(^) International Trade (2019)

Primary Trading Partner (Imports): China
Primary Trading Partner (Exports): Canada

Domestic Production and Consumption

Total domestic manufacturing of ferrous sulfate reported under
the TSCA CDR was approximately 18 M kg in 2015. Significantly,
several domestic manufacturers of ferrous sulfate did not report
production. Due to this data gap and differences in reporting
between production and trade data, U.S. consumption of ferrous
sulfate could not be estimated.


Ferrous Sulfate Supply Chain - Full Profile

Product Description

Ferrous sulfate (FeS04), an iron salt, is widely used in food, agriculture and chemical production. In water
treatment it is a commonly used coagulant. Ferrous sulfate is primarily produced as a byproduct of steel pickling,
a process that relies on iron oxides and sulfuric acid.

Use in Water Treatment

Ferrous sulfate is used as a coagulant in both wastewater and drinking water treatment (AWWA, 2018).

Use as a Precursor to Other Water Treatment Chemicals
Ferrous sulfate is used to manufacture ferric sulfate.

Other Applications

Ferrous sulfate is used as a component of fertilizer, an additive in animal feed, pharmaceuticals, iron fortification
of foods, and as a pigment (NCBI, 2021).

Primary Industrial Consumers

Historically, use in fertilizer and as an animal feed additive have been the primary domestic uses of ferrous
sulfate. Water treatment is a significant use of ferrous sulfate, historically accounting for up to 30% of domestic
consumption (NCBI, 2021).

Manufacturing, Transport, & Storage

Manufacturing Process

Ferrous sulfate can be produced with a number of starting materials. Iron, ferrous oxide, and sulfuric acid are
the primary materials used to produce ferrous sulfate. Ilmenite, the raw material used to produce titanium
dioxide, can also be used but is a less common source of iron oxides in North America.

The method most commonly used in North America utilizes a reaction of spent steel pickling liquors or scrap
iron with sulfuric acid. Pickling of steel removes the surface iron oxide from steel by immersion in a bath
containing either a sulfuric or hydrochloric acid solution. When sulfuric acid is used, mixed oxides in the
oxidation layer of the steel as well as the underlying iron react with the sulfuric acid to form ferrous sulfate as
shown in Figure 1. Ferrous sulfate is then filtered and crystallized to complete the production (Barben Analytical,
2015; de Buzin et al., 2014; EPA, 2001).

Reaction of Mixed Iron Oxides (Fe203, Fe304, and FeO) and Steel with Sulfuric Acid

Iron Oxide


Steel + Sulfuric Acid

> Ferrous Sulfate + Water



Fe + 3H2SO4

> 3FeS04 + 3H2O

Iron Oxide


Steel + Sulfuric Acid

> Ferrous Sulfate + Water



Fe + 4H2S04

-> 4FeS04 + 4H20

Iron Oxide


Sulfuric Acid > Ferrous Sulfate + Water



H2SO4 ->

FeS04 + H2O

Iron + Sulfuric Acid > Ferrous Sulfate + Hydrogen
Fe + H2SO4 > FeS04 + H2

Figure 1. Chemical Equation for the Reaction to Manufacture Ferrous Sulfate

EPA 817-F-22-027 | December 2022


Ferrous Sulfate Supply Chain - Full Profile

Production as a byproduct of the manufacture of titanium dioxide results from the process to remove the iron
oxide impurities present in low-grade ilmenite. Acid leaching processes include hydrochloric acid or sulfuric acid
leaching. Prior to leaching, pretreatment includes reduction or sequential oxidation and reduction. In the sulfate
process, the ilmenite is then digested with sulfuric acid, yielding a titanium sulfate solution which is hydrolyzed
and precipitated to form titanium dioxide and a waste stream of ferrous sulfate (EPA, 2001).

Product Transport

Ferrous sulfate is transported by many means including truck, rail, barge, and ship.

Storage and Shelf Life

Ferrous sulfate is stable under recommended storage conditions, but degrades when exposed to direct sun and
heat. When stored properly, ferrous sulfate can have a shelf life greater than twelve months, though stability
may depend upon many factors (Affinity Chemical, 2019).

Domestic Production & Consumption

Domestic Production

Production data was collected from the 2016 EPA Toxic Substances Control Act (TSCA) Chemical Data Reporting
(CDR) for the year 20151, while trade data was collected from the U.S. International Trade Commission (USITC)
Dataweb, as shown in Table 1. While production data is specific to ferrous sulfate, trade data includes ferrous
sulfate as part of a broader trade category of metal sulfates. For imports, the trade category is specific to iron
sulfates, while the export trade category includes ferrous sulfate among metal sulfates, 'not elsewhere specified'

Table 1. Ferrous Sulfate Production and Trade Data Sources

Production and Trade Data


Data Source



Domestic Production

2016 EPA CDR

CAS No.: 7720-78-7

Ferrous Sulfate

Imports and Exports

U.S. International Trade

HTS Code (Imports): 2833.29.2000
HS Code (Exports): 2833.29

Iron Sulfates
Metal Sulfates, NES

Total U.S. domestic manufacturing of ferrous sulfate reported under the CDR was approximately 18 million
kilograms (M kg) in 2015; however, several manufacturers claimed confidential business information and did not
report production volumes to EPA. Domestic commercial manufacture of ferrous sulfate takes place at a limited
number of facilities throughout the contiguous U.S. Primary producers include USALCO (formerly Altivia
Chemicals), Kemira Water Solutions, and Keystone Steel and Charter Steel (steel manufacturer). Most ferrous
sulfate production facilities are associated with the steel industry. The number of domestic manufacturing
locations shown in Figure 2 represents operating facilities as of 2015 (EPA, 2016). Supply of NSF/ANSI Standard
60 certified ferrous sulfate for use in drinking water treatment is limited to a few locations throughout the U.S.
(NSF International, 2021). For a more current listing of manufacturing locations and supplier locations, visit the
U.S. Environmental Protection Agency's (EPA's) Chemical Locator Tool (EPA, 2022a).

1 Although 2019 CDR data is available, reporting is less complete when compared to 2015 data due to an increase in the number of
companies claiming confidential business information (CBI). In both instances, CBI may account for a significant volume of ferrous sulfate
produced that is not reflected in CDR reporting.


Ferrous Sulfate Supply Chain - Full Profile

Figure 2. Domestic Supply and Manufacturing of Ferrous Sulfate
Domestic Consumption

Due to differences in reporting for production and trade data, as well as the significant number of producers
that did not report production data under the CDR, U.S. consumption of ferrous sulfate could not be estimated.
Domestic production of ferrous sulfate may represent a small quantity when compared to the import and export
volume for the category of sulfates including ferrous sulfate.

Trade & Tariffs
Worldwide Trade

Worldwide import and export data for ferrous sulfate are reported through the World Bank's World Integrated
Trade Solutions (WITS), as a category representing metal sulfates, NES. In 2021, the U.S. ranked 18th worldwide
in total exports and second in total imports of metal sulfates, NES. In 2021, Germany ranked first worldwide in
total exports and imports (WITS, 2022), as shown in Table 2. Import and export data specific to ferrous sulfate is
unavailable from the referenced sources.


Ferrous Sulfate Supply Chain - Full Profile
Table 2. WITS Worldwide Export and Import of Metal Sulfates, NES, Including Ferrous Sulfate in 2021

2021 Worldwide Trade
Metal Sulfates, NES (HS Code 2833.29)

Top 5 Worldwide Exporters

Top 5 Worldwide Importers


836 M kg


348 M kg


636 M kg

United States

267 M kg


257 M kg


144 M kg


129 M kg

United Kingdom

99 M kg


119 M kg


93 M kg

Domestic Imports and Exports

Domestic imports and export data are reported by USITC in categories for metal sulfates. For imports, the
trade category is specific to iron sulfates, while the export trade category includes metal sulfates, NES. Figure 3
summarizes imports for consumption2 and domestic exports3 between 2015 and 2020. During this period, the
overall quantity of imports varied between 62 and 94 M kg. The quantity of exports was consistently much
smaller than the quantity of imports. Over this five-year period, Canada was the primary recipient of domestic
exports while China replaced Canada and Spain as the primary source of imports (USITC, 2021).


J? 60


2 40



Domestic Trade of Iron Sulfates (Imports) and Metal Sulfates, NES (Exports)

HS Code 2833.29

.. I. I. I. I.

2015 2016 2017	2018 2019	2020

	Imports from China	 Exports to Canada

	Imports from Spain	I Exports to Mexico

I Imports from Other Countries	Exports to Other Countries

Figure 3. USITC Domestic Import and Export of Iron Sulfates, including Ferrous Sulfate between 2015 and 2020

2	Imports for consumption are a subset of general imports, representing the total amount cleared through customs and entering
consumption channels, not anticipated to be reshipped to foreign points, but may include some reexports.

3	Domestic exports are a subset of total exports, representing export of domestic merchandise which are produced or manufactured in
the U.S. and commodities of foreign origin which have been changed in the U.S.


Ferrous Sulfate Supply Chain - Full Profile


There is no general duty for import of ferrous sulfate, however there is an additional 25% duty for imports from
China (USITC, 2022), as summarized in Table 3.

Table 3. 2021 Domestic Tariff Schedule for Iron Sulfates, including Ferrous Sulfate

HTS Number

General Duty

Additional Duty - China
(Section 301 Tariff List)

Special Duty





Market History & Risk Evaluation

History of Shortages

The production of ferrous sulfate in North America is heavily reliant on the steel industry and availability of
sulfuric acid. Economic slowdowns and a drop in domestic steel manufacturing along with greater recycling of
steel pickling liquor and fluctuating prices for sulfuric acid have been known to impact the availability of ferrous

Risk Evaluation

The complete risk assessment methodology is described in Understanding Water Treatment Chemical Supply
Chains and the Risk of Disruptions (EPA, 2022b). The risk rating is calculated as the product of the following three
risk parameters:

Risk = Criticality x Likelihood x Vulnerability
Criticality	Measure of the importance of a chemical to the water sector

Likelihood Measure of the probability that the chemical will experience a supply disruption in the
future, which is estimated based on past occurrence of supply disruptions

Vulnerability Measure of the market dynamics that make a chemical market more or less resilient to
supply disruptions

The individual parameter rating is based on evaluation of one or more attributes of the chemical or its supply
chain. The ratings and drivers for these three risk parameters are shown below in Table 4.


Ferrous Sulfate Supply Chain - Full Profile

Table 4. Supply Chain Risk Evaluation for Ferrous Sulfate

Risk Parameter Ratings and Drivers

1 1


ICriticality High

1 Likelihood Low 1

Vulnerability Low 1

Ferrous sulfate is an essential water
treatment chemical. It is widely used
as a coagulant and serves as a
precursor in manufacturing ferric

The water sector has experienced
price fluctuations in the past, but has
not experienced supply chain
disruptions between 2000 and 2022.

Strong domestic manufacturing
capabilities and a distributed
manufacturing base provide some
resilience to supply disruptions.
However, the reliance on the steel
industry may increase vulnerability.

Risk Rating: Low



Xe-Low Modern



k %

1 1


Affinity Chemical, 2019. Safety Data Sheet for Ferrous Sulfate Solution, retrieved from


American Waterworks Association (AWWA), 2018. B402 Ferrous Sulfate. Denver, CO: American Water
Works Association.

Barben Analytical, 2015. Application Note, Titanium Dioxide - Sulfate Process, retrieved from

de Buzin, P.J.W.K., Viganico, E.M., Silva, R.D.A., Heck, N.Z., Schneider, I.A.H. and Menezes, J.C.S.S., 2014.
Production of Ferrous Sulfate From Steelmaking Mill Scale. International Journal of Scientific &
Engineering Research, 5(4):353-359.

EPA, 2001. Final Titanium Dioxide Listing Background Document for the Inorganic Chemical Listing

Determination, retrieved from https://archive.epa.gov/epawaste/hazard/web/pdf/tio2-bd.pdf

EPA, 2016. 2016 TSCA Chemical Data Reporting, retrieved from https://www.epa.gov/chemical-data-

EPA, 2022a. Chemical Suppliers and Manufacturers Locator Tool, retrieved from


EPA, 2022b. Understanding Water Treatment Chemical Supply Chains and the Risk of Disruptions, retrieved
from https://www.epa.gov/waterutilityresponse/risk-disruptions-supply-water-treatment-chemicals

National Center for Biotechnology Information (NCBI), 2021. PubChem Compound Summary for CID 24393,
Ferrous Sulfate, retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/24393

NSF International, 2021. Search for NSF Certified Drinking Water Treatment Chemicals, retrieved from


Ferrous Sulfate Supply Chain - Full Profile

U.S. International Trade Commission, 2021. USITC DataWeb, retrieved from https://dataweb.usitc.gov/
U.S. International Trade Commission (USITC), 2022. Harmonized Tariff Schedule (HTS) search, retrieved from

World Integrated Trade Solutions, 2022. Trade Statistics by Product (HS 6-digit), retrieved from