Sodium Silicate Supply Chain - Executive Summary

Sodium Silicate

Direct Use Chemical

Na20 (Si02)x
(liquid, solid)

Inputs to Manufacturing Process:


Sodium Carbonate Sodium Hydroxide

J* Derivative Water Treatment Chemicals:



% of Total Domestic Consumption
Attributed to Water Sector:

Less than 6%

Understanding Chemical Supply Chains
Map of Suppliers & Manufacturers

A. Product Family:

CAS No.: 1344-09-8

2 Shelf Life:
12 Months


RISK RATING: Moderate-Low

,e(ate-Low Mo derate,


Distributed domestic man-
ufacturing provides some
resilience to supply disrup-
tions. However, a key in-
put, sodium carbonate,
though domestically pro-
duced in large quantities,
is only produced in two
geographic locations.


Criticality: High. Essential for corrosion
control and coagulation.

Likelihood: Low. The water sector did
not experience sodium silicate supply
disruptions between 2000 and 2022.

Vulnerability: Moderate-Low. Strong
domestic manufacturing and distribu-
tion, however domestic production of
a key input, sodium carbonate, is geo-
graphically limited.



Sodium Carbonate
Sodium Hydroxide

Input	End Use

Sodium Silicate

Water Treatment Applications


	Corrosion control

Other Applications

Cardboard construction
Detergents and cleaning products


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

(^) International Trade (2019)

PrimaryTrading Partner (Imports): Canada
PrimaryTrading Partner (Exports): Canada

Domestic Consumption (2019):

155 M kg

	Domestic Production (131 M kg)

	Imports for Consumption (45 M kg)

	Export of Domestic Production (20 M kg)


Sodium Silicate Supply Chain - Full Profile

Product Description

Sodium silicates (Na20-(Si02)x), are a class of alkaline salts with varying formulations widely used across a variety
of industries. Sodium silicates are used in water treatment for corrosion control and as a coagulant aid. Sodium
silicate is widely used for cardboard construction and formulation of cleaning products and detergents.

Use in Water Treatment

Sodium silicate is used directly in water treatment as a component of activated silica coagulant aids, for
corrosion control, and for iron and manganese stabilization (AWWA, 2008).

Use as a Precursor to Other Water Treatment Chemicals

Sodium silicate is not used as a precursor in the commercial manufacture of other water treatment chemicals.
Other Applications

Sodium silicates are most commonly used in detergent and cleaning product formulations and cardboard
construction. Other applications include use in hydraulic fracturing well stabilization, soil stabilization, concrete
manufacturing, silica gels, paints and coatings, as an adhesive, and as a food additive (NCBI, 2021; PQ, 2004a;
PQ, 2021).

Primary Industrial Consumers

Cardboard construction and detergent and cleaning product formulations are the primary applications of
sodium silicates. Use as an adhesive and as a drilling fluid and well stabilizer are other significant applications.
Water treatment, including industrial water treatment, is estimated as 6% of overall sodium silicate
consumption (NCBI, 2021).

Manufacturing, Transport, & Storage

Manufacturing Process

A significant quantity of sodium silicate produced in the U.S. starts with silica and sodium carbonate and utilizes
the furnace process. The other significant production method utilizes sodium hydroxide instead of sodium
carbonate in order to produce alkali silicates.

Sodium silicate is a generic term for a variety of compounds containing silicon, oxygen, and sodium. Sodium
silicate compounds are represented by the formula Na20-(Si02)x, where x is the ratio of silicon dioxide (Si02) to
sodium oxide (Na20) by weight. The ratio determines the physical and chemical properties of the product,
resulting in various applications for sodium silicate. The commercial ratio for liquid sodium silicates ranges from
1.8 to 3.75 and the commonly used ratio for sodium silicate in water treatment is 3.2 (AWWA, 2008; PQ, 2021).

The most common sodium silicate manufacturing process proceeds in several steps, the overall equation for this
process is outlined in Figure 1. Measured proportions of silica sand and sodium carbonate are fused in a furnace
at high heat. The product from the first phase, which is an amorphous glass called sodium silicate lumps or cullet
is dissolved in water at elevated temperature and pressure to produce a silicate solution. The silicate solution is
then filtered to yield the final product. The ratio may be adjusted at this stage by adding sodium hydroxide to
obtain the desired ratio of silicon dioxide to sodium oxide (Fawer et al., 1999; PQ, 2004b).

EPA 817-F-22-049 | December 2022


Sodium Silicate Supply Chain - Full Profile

Sodium Carbonate + Silica > Sodium Silicate + Carbon Dioxide
Na2CC>3	+ xSiC>2 ^ Na20*(Si02)x + CO2

Figure 1. Chemical Equation for the Reaction to Manufacture Sodium Silicate

Product Transport

Sodium silicate, primarily supplied as a solution but also available as a solid or powder, is widely transported in
container and bulk by truck, rail, barge, and ship. When transported as a solution, transportation costs due to
high water content may increase the cost of the delivered product (PQ, 2004a; PQ 2021).

Storage and Shelf Life

Sodium silicate, should be stored in a tightly closed container and kept in a cool place away from direct sunlight.
When stored properly, sodium silicate can have a shelf life of approximately 12 months, depending on storage
conditions and size of storage container (PQ, 2004b).

Domestic Production & Consumption

Domestic Production

Production data was collected from the 2020 Toxic Substances Control Act (TSCA) Chemical Data Reporting
(CDR) for the year 2019, while trade data was collected from the U.S. International Trade Commission (USITC)
Dataweb, as shown in Table 1. Both production and trade data are specific to sodium silicate.

Table 1. Sodium Silicate Production and Trade Data Sources

Production and Trade Data


Data Source and Date



Domestic Production

2020 TSCA Chemical Data Reporting

CAS No.: 1344-09-8

Sodium Silicate

Imports and Exports

U.S. International Trade Commission

HS Code: 2839.19

Sodium Silicate

Total U.S. domestic manufacturing of sodium silicate reported under the CDR was approximately 155 million
kilograms (M kg) in 2019 (EPA, 2020). Evonik indicated production of approximately 64% of total domestic
production, though a considerable number of manufacturers claimed confidential business information for
production volumes, including leading domestic manufacturer PQ Corporation. 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 sodium silicate for use in drinking water treatment is distributed 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).



Sodium Silicate Supply Chain - hull Profile

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Domestic Supply and Manufacturing of Sodium Silicate
O 47 NSF/ANSI Standard 60 Certified Suppliers (NSF International, 2021)
25 Domestic Manufacturing Locations (EPA Chemical Data Reporting, 2016)


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Figure 2. Domestic Supply and Manufacturing of Sodium Silicates
Domestic Consumption

U.S. consumption of sodium silicate in 2019 is estimated at 155 M kg. This includes production of 131
import of 45 M kg, minus export of 20 M kg (EPA, 2020; USITC, 2022a), as shown in Figure 3.

M kg,

Domestic Consumption (2019):
155 M kg

P Domestic Production (131 M kg)

	Imports for Consumption (45 M kg)

	Export of Domestic Production (20 M kg)

Figure 3. Domestic Production and Consumption of Sodium Silicate in 2019



Sodium Silicate Supply Chain - Full Profile

Trade & Tariffs

Worldwide Trade

Worldwide import and export data for sodium silicate are reported through the World Bank's World Integrated
Trade Solutions (WITS), as sodium silicates. In 2021, the U.S. ranked 14th worldwide in total exports and third in
total imports of sodium silicates. In 2021, China ranked first worldwide in total exports and South Korea first in
total imports (WITS, 2022), as shown in Table 2.

Table 2. WITS Worldwide Export and Import of Sodium Silicates in 2021

2021 Worldwide Trade
Sodium Silicates (HS Code 2839.19)

Top 5 Worldwide Exporters

Top 5 Worldwide Importers


309 M kg

South Korea

126 M kg


207 M kg


121 M kg


121 M kg

United States

100 M kg


60 M kg


90 M kg


52 M kg


62 M kg

Domestic Imports and Exports

Domestic imports and export data are reported by USITC in a category specific to sodium silicates. Figure 4
summarizes imports for consumption1 and domestic exports2 of sodium silicates between 2015 and 2020.

During this period, the overall quantity of exports and imports varied with no clear pattern. Over this five-year
period, Canada was the primary recipient of domestic exports and the primary source of imports (USITC, 2022a).


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Figure 4. USITC Domestic Import and Export of Sodium Silicates between 2015 and 2020

1	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.

2	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.

Domestic Trade of Sodium Silicate
HTS Code 2839.19


1 ll ll ll



2 Imports



2 Imports



2 Imports




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jj c




	Imports from Canada	 Exports to Canada

	Imports from Netherlands	 Exports to Japan
Imports from Other Countries Exports to Other Countries



Sodium Silicate Supply Chain - Full Profile


There is a 1.1% general duty for import of sodium silicate and an additional 25% duty on imports from China
(USITC, 2022b), as summarized in Table 3.

Table 3. 2021 Domestic Tariff Schedule for Sodium Silicates

HS Code

General Duty

Additional Duty - China
(Section 301 Tariff List)

Special Duty




Free (A, All, BH, CL, CO, D, E, IL, JO, KR, MA,
OM, P, PA, PE, S, SG)3

Market History & Risk Evaluation

History of Shortages

There were no identified sodium silicate supply chain disruptions between 2000 and 2022.

Risk Evaluation

The complete risk evaluation 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.

3 Symbols used to designate the various preference programs and trade agreements. A full list of special trade agreements and
associated acronyms can be found at https://help.cbp.eov/s/article/Article-310?laneuaee=en US and the General Notes Section of the
Harmonized Tariff Schedule https://hts.usitc.eov/current



Sodium Silicate Supply Chain - Full Profile

Table 4. Supply Chain Risk Evaluation for Sodium Silicate

Risk Parameter Ratings and Drivers

ICriticality High 1

1 Likelihood Low 1

Sodium silicate is essential to the

The water sector has not experienced

Strong domestic manufacturing

water sector for coagulation and

sodium silicate supply disruptions

capabilities and a distributed

corrosion control.

between 2000 and 2022.

manufacturing base provide some
resilience to supply disruptions.
However, a key input, sodium
carbonate, though produced in large
quantities in the U.S., is limited to
domestic manufacturing in only two
geographic locations.

Risk Rating: Moderate-Low

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American Water Works Association (AWWA), 2008. B303, Liquid Sodium Silicate. Denver, CO: American
Water Works Association.

EPA, 2016. 2016 TSCA Chemical Data Reporting, retrieved from

EPA, 2020. 2020 TSCA Chemical Data Reporting, retrieved from

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

EPA, 2022b. Understanding Water Treatment Chemical Supply Chains and the Risk of Disruptions, retrieved

Fawer, M., Concannon, M. and Rieber, W., 1999. Life cycle inventories for the production of sodium
silicates. The International Journal of Life Cycle Assessment, 4(4): 207-212.

National Center for Biotechnology Information (NCBI), 2020. PubChem Compound Summary for CID
23668197, Sodium silicate, retrieved from

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



Sodium Silicate Supply Chain - Full Profile

PQ Corporation (PQ), 2004a. Applications of PQ Soluble Silicates, retrieved from

PQ Corporation (PQ), 2004b. Sodium and Potassium Silicates - Versatile compounds for your applications,
retrieved from

PQ Corporation (PQ), 2021. 2020 Annual Report, retrieved from

U.S. International Trade Commission (USITC), 2022a. USITC DataWeb, retrieved from

U.S. International Trade Commission (USITC), 2022b. Harmonized Tariff Schedule (HTS) Search, retrieved

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