Calcium Hydroxide Supply Chain - Executive Summary

Calcium Hydroxide (Slaked Lime)

Direct Use Chemical | pl-ecursor Chemical

Ca(OH)2
(liquid, solid)

Source of Raw Material:

Calcium Oxide (Quicklime)

Derivative Water Treatment Chemicals:
Calcium Hypochlorite

% of Total Domestic Consumption
Attributed to Water Sector:

Less than 7%

Understanding Chemical Supply Chains
Map of Suppliers & Manufacturers

Product Family:
Calcium

CAS No.: 1305-62-0

2 Shelf Life:
6 Months

— RISK OF SUPPLY DISRUPTION (Assessed in 2022)









PRODUCTION PROCESS

Calcium Oxide

Calcium Hydroxide

Input

End Use

Water Treatment Applications

Precipitative softening
pH adjustment

Water treatment chemical production
Other Applications

Steel manufacturing and other metal refining
Environmental use including acid mine drainage
Chemical manufacturing
Construction

DOMESTIC PRODUCTION AND CONSUMPTION, AND INTERNATIONAL TRADE

Domestic Production Locations (2018):
47, distributed throughout the U.S.

(^) International Trade (2019)

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

Domestic Consumption (2018):
2,696 M kg

¦	Domestic Production (2,690 M kg)

¦	Imports for Consumption (51 M kg)

¦	Export of Domestic Production (46 M kg)

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Calcium Hydroxide Supply Chain - Full Profile

Product Description

Calcium hydroxide (Ca(OH)2), also known as hydrated lime or slaked lime, is a widely used derivative of calcium
oxide (quicklime). Calcium hydroxide is used directly in water treatment for precipitative softening and pH
adjustment, and also as an input in the manufacturing of calcium hypochlorite.

Use in Water Treatment

Calcium hydroxide is used directly in precipitative softening pH adjustment.

Use as a Precursor to Other Water Treatment Chemicals
Calcium hydroxide is used to manufacture calcium hypochlorite.

Other Applications

Lime, including both calcium oxide (quicklime) and calcium hydroxide (slaked lime), has a wide range of
applications. The leading domestic use of lime is as a flux and slagging agent to remove impurities as part of
steel manufacturing. Other metallurgical uses include beneficiation of copper and zinc ores, bauxite processing,
and recovery of uranium and nickel. Other metallurgical uses include beneficiation of copper and zinc ores,
bauxite processing, and recovery of uranium and nickel. Lime also has environmental remediation applications
including treatment of acid mine drainage and heavy metal contamination, as well as construction applications
including soil stabilization, asphalt manufacturing, as a component of mortar and plaster, and alkali chemical
manufacturing (USGS, 2021).

Primary Industrial Consumers

Domestic consumption information identifies consumers of lime, including both calcium hydroxide (slaked lime)
and calcium oxide (quicklime). Calcium oxide is the predominant form of lime consumed. In 2018, approximately
35% of lime consumed in the U.S. was used for ferrous and nonferrous metallurgy. Additional applications
include environmental uses (29%), chemical and industrial use (21%), construction use (10%), miscellaneous
uses (3%), and use for refractories (1%) (USGS, 2021). Commercial sale of lime accounted for 94% of total
domestic consumption in 2018, while captive consumption, including sugar refining and precipitated calcium
carbonate manufacturing, accounted for the remaining 6%. Use of lime (calcium oxide and calcium hydroxide) in
wastewater and drinking water accounted for approximately 7% of 2018 domestic consumption (USGS, 2021).

Manufacturing, Transport, & Storage

Manufacturing Process

Manufacturing of calcium hydroxide primarily relies on ground calcium oxide (quicklime) from high-calcium
limestone. A precise amount of water is slowly added to ground or crushed calcium oxide to produce a dry,
white powder in a highly exothermic reaction. The powder may be further refined by air separation to remove
coarse particles (National Lime Association, n.d.). The overall equation for this process is outlined in Figure 1.

Calcium Oxide +

Water

—» Calcium Hydroxide

CaO +

H20

-> Ca(OH)2

Figure 1. Chemical Equation for the Reaction to Manufacture Calcium Hydroxide

Product Transport

Calcium hydroxide is commonly transported by rail, truck, and waterway. Though widely manufactured
throughout the U.S., there are areas without local access to calcium hydroxide plants, and transportation costs

EPA 817-F-22-016 | December 2022

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Calcium Hydroxide Supply Chain - Full Profile

may significantly increase the cost of the delivered product (USGS, 2021).

Storage and Shelf Life

Calcium hydroxide is stable and non-combustible. When stored properly, calcium hydroxide can have a shelf life
of approximately 6 months (Mississippi Lime, 2015).

Domestic Production & Consumption

Domestic Production

Production data was collected from USGS, 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 calcium
hydroxide.

Table 1. Calcium Hydroxide Production and Trade Data Sources

Production and Trade Data

Category

Data Source

Identifier

Description

Domestic Production

U.S. Geological Survey

CAS No.: 1305-62-0

Calcium Hydroxide

Imports and Exports

U.S. International Trade
Commission

HS Code: 2522.20

Calcium Hydroxide (slaked lime)

Total U.S. domestic production of calcium hydroxide for commercial sale was approximately 2,690 million
kilograms (M kg) in 2018 (USGS, 2021). Because calcium hydroxide requires only the addition of water to calcium
oxide, many calcium oxide production locations also manufacture calcium hydroxide. Of the 74 calcium oxide
manufacturing locations operating in 2018, domestic commercial production of calcium hydroxide took place at
29 of these locations in addition to 18 stand-alone calcium hydroxide manufacturing plants. Calcium hydroxide
represents a fraction of overall lime production, with the majority (84%) of lime produced for use as calcium
oxide. The number of domestic manufacturing locations shown in Figure 2 represents operating facilities as of
2018 (USGS, 2021). Supply of NSF/ANSI Standard 60 certified calcium oxide 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).

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Calcium Hydroxide Supply Chain - Full Profile

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Domestic Supply and Manufacturing of Calcium Hydroxide
O 26 NSF/ANSI Standard 60 Certified Suppliers (NSF International, 2021)

9 47 Domestic Manufacturing Locations (USGS, 2021)

Figure 2. Domestic Supply and Manufacturing of Calcium Hydroxide
Domestic Consumption

U.S. consumption of calcium hydroxide in 2018 is estimated at 2,696 M kg. This estimate includes production of
2,690 M kg, import of 51 M kg, minus export of 46 M kg (USGS, 2021; USITC, 2021), as shown in Figure 3.

Domestic Consumption (2018):

2,696 M kg

¦	Domestic Production (2,690 M kg)

¦	Imports for Consumption (51 M kg)

¦	Export of Domestic Production (46 M kg)

Figure 3. Domestic Production and Consumption of Calcium Hydroxide in 2018

Trade &Tariffs
Worldwide Trade

Worldwide import and export data for calcium hydroxide (slaked lime) is reported through the World Bank's

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Calcium Hydroxide Supply Chain - Full Profile

World Integrated Trade Solutions (WITS) software, as a category specific to calcium hydroxide. In 2021, the U.S.
ranked 21st worldwide in total exports and seventh in total imports of calcium hydroxide. In 2021, Germany
ranked first worldwide in total exports and Zimbabwe ranked first worldwide in total imports (WITS, 2022) as
shown in Table 2.

Table 2. WITS Worldwide Export and Import of Calcium Hydroxide in 2021

2021 Worldwide Trade
Calcium Hydroxide (Slaked Lime) (HS Code 2522.20)

Top 5 Worldwide Exporters

Top 5 Worldwide Importers

Germany

103 M kg

Zimbabwe

785 M kg

United Kingdom

83 M kg

Philippines

87 M kg

Malaysia

82 M kg

Germany

70 M kg

Zambia

67 M kg

Singapore

66 M kg

Oman

63 M kg

Netherlands

62 M kg

Domestic Imports and Exports

Domestic import and export data are reported by USITC in categories specific to calcium hydroxide. Figure 4
summarizes imports for consumption1 and domestic exports2 of calcium hydroxide between 2015 and 2020.
During this period, the overall quantity of imports remained relatively steady, while exports rose and fell, with
the largest volume exported in 2018. Over this five-year period, Canada was the primary recipient of domestic
exports and the primary source of imports (USITC, 2021).

Domestic Trade of Calcium Hydroxide (Slaked Lime)
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Figure 4. USITC Domestic Import and Export of Calcium Hydroxide 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.

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Calcium Hydroxide Supply Chain - Full Profile

Tariffs

Imports of calcium hydroxide are primarily supplied from Canada. There is no general duty for import of calcium
hydroxide, however there is an additional 25% duty on imports from China (USITC, 2022), as summarized in
Table 3.

Table 3. 2020 Domestic Tariff Schedule for Calcium Hydroxide

HS Code

General Duty

Additional Duty - China
(Section 301 Tariff List)

Special Duty

2522.20

None

25%

None

Market History & Risk Assessment

History of Shortages

Calcium hydroxide is widely manufactured and used in a variety of industries. There were no identified calcium
hydroxide supply chain disruptions between 2000 and 2022.

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.

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Calcium Hydroxide Supply Chain - Full Profile

Table 4. Supply Chain Risk Evaluation for Calcium Hydroxide

Risk Parameter Ratings and Drivers



I

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ICriticality High

1 Likelihood Low



Vulnerability Low 1

Calcium hydroxide is widely used in
water treatment for softening and pH
adjustment. It is a precursor in the
production of calcium hypochlorite.

The water sector has not experienced
calcium hydroxide supply disruptions
between 2000 and 2022.



The U.S. is a leading producer of the
key raw material of calcium
hydroxide, calcium carbonate.
Manufacturing and supply are widely
distributed.

Risk Rating: Low

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References

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

https://www.epa.gov/waterutilityresponse/chemical-suppliers-and-manufacturers-locator-tool
EPA, 2022b. Understanding Water Treatment Chemical Supply Chains and the Risk of Disruptions, retrieved

from https://www.epa.gov/waterutilityresponse/risk-disruptions-supplv-water-treatment-chemicals
Mississippi Lime, 2015. Shelf Life of Mississippi Lime Products, retrieved from

https://www.mississippilime.com/wp-content/uploads/2015/02/Shelf-Life-of-Products-June-2015.pdf
National Lime Association, n.d. How Lime is Made, retrieved from https://www.lime.org/lime-basics/how-
lime-is-made/

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

https://info.nsf.org/Certified/PwsChemicals/

U.S. Geological Survey (USGS), 2021. 2018 Minerals Yearbook: Lime, retrieved from https://d9-wret.s3.us-

west-2.amazonaws.com/assets/palladium/production/atoms/files/mvbl-2018-lime.pdf
U.S. International Trade Commission (USITC), 2021. Harmonized Tariff Schedule (HTS) Search, retrieved from

https://hts.usitc.gov/

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

https://dataweb.usitc.gov/

World Integrated Trade Solutions (WITS), 2022. Trade Statistics by Product (HS 6-digit), retrieved from
https://wits.worldbank.org/trade/countrv-bvhs6product.aspx?lang=en#void

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