Calcium Oxide Supply Chain - Executive Summary

Calcium Oxide (Quicklime)

Direct Use Chemical Precursor Chemical

CaO
(solid)

Source of Raw Material:
Calcium Carbonate (Limestone)

% of Total Domestic Consumption
Attributed to Water Sector:

Less than 7%

Derivative Water Treatment Chemicals: Understanding Chemical Supply Chains
Calcium Hydroxide	Map of Suppliers & Manufacturers

Product Family
Calcium

CAS No.: 1305-78-8

2 Shelf Life:
3 Months

— RISK OF SUPPLY DISRUPTION (Assessed in 2022)

RISK RATING: Low

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RISK DRIVERS

Calcium oxide is used in a
variety of industries and is
widely manufactured and
supplied. The key input
(calcium carbonate) is
currently abundant and
supplied from domestic
sources.

RISK PARAMETERS

Criticality: High. Essential for softening,
sludge treatment, and production of
water treatment chemicals.

Likelihood: Low. The water sector has not
experienced calcium oxide supply disrup-
tions between 2000 and 2022.

Vulnerability: Low. Manufacturing and sup-
ply is widely distributed. Key raw material
(calcium carbonate) is abundant and widely
available.

PRODUCTION PROCESS

Water Treatment Applications

DOMESTIC PRODUCTION AND CONSUMPTION, AND INTERNATIONAL TRADE

Domestic Production Locations (2018):

74, widely distributed across 28 states.

(^) International Trade (2019)

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

Domestic Consumption (2018):

15,170 M kg

¦	Domestic Production (15,200 M kg)

¦	Imports for Consumption (265 M kg)

¦	Export of Domestic Production (295 M kg)

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Calcium Oxide Supply Chain - Full Profile

Product Description

Calcium oxide (CaO), also known as quicklime, is a widely used derivative of calcium carbonate (limestone).
Calcium oxide is used directly in water treatment for precipitative softening and sludge treatment, and also as
an input in the manufacturing of calcium hydroxide.

Use in Water Treatment

Calcium oxide is used directly in precipitative softening and sludge treatment.

Use as a Precursor to Other Water Treatment Chemicals
Calcium oxide is used to manufacture calcium hydroxide (slaked lime).

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. 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, 2020; USGS 2021).

Primary Industrial Consumers

Domestic consumption information identifies consumers of lime, including both calcium oxide (quicklime) and
calcium hydroxide (slaked lime). Calcium oxide is the predominant form of lime consumed. In 2018,
approximately 35% of calcium oxide 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

The majority of calcium oxide produced in the U.S. starts with calcium carbonate (limestone) and utilizes a
calcining process. Magnesium carbonate (dolomite) may also be used as a raw material.

Lime manufacturing begins with crushed calcium carbonate (limestone), which may vary considerably in
composition and structure by source. Subsequent processing, including calcining, will include process variations
according to the raw material characteristics. After beneficiation, calcium carbonate is calcined in a carbon
dioxide-rich environment at a temperature high enough to promote thermal decomposition of the calcium
carbonate to calcium oxide. The overall equation for this process is outlined in Figure 1.	

Calcium Carbonate + Heat —» Calcium Oxide + Carbon Dioxide
CaC03	+ heat —>	CaO + CO2

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

EPA 817-F-22-018 | December 2022

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Calcium Oxide Supply Chain - Full Profile

Product Transport

Calcium oxide is commonly transported by rail, truck, and waterway. Though widely manufactured throughout
the U.S., there are areas without local access to calcium oxide plants, and transportation costs may significantly
increase the cost of the delivered product (USGS, 2021).

Storage and Shelf Life

Calcium oxide is stable and non-combustible, though it reacts exothermically with water. When stored properly,
calcium oxide can have a shelf life of approximately 3 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 oxide.

Table 1. Calcium Oxide Production and Trade Data Sources

Production and Trade Data

Category

Data Source

Identifier

Description

Domestic Production

U.S. Geological Survey

CAS No.: 1305-78-8

Calcium Oxide

Imports and Exports

U.S. International Trade Commission

HS Code: 2522.10

Calcium Oxide (Quicklime)

Total U.S. domestic production of calcium oxide for commercial sale was approximately 15,200 million kilograms
(M kg) in 2018 (USGS, 2021). In 2018, domestic commercial production of calcium oxide took place at 74
locations in 28 states. Production volume was highest in the Midwest, followed by the southern U.S., and
Missouri, Alabama, Kentucky, Ohio, and Texas were the top producing states (USGS, 2021). The majority of
quicklime produced is high-calcium quicklime. In 2018, ten companies with 45 locations accounted for 90% of
calcium oxide production. 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 Oxide Supply Chain - Full Profile

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Domestic Supply and Manufacturing of Calcium Oxide
O 14 NSF/ANSI Standard 60 Certified Suppliers (NSF International, 2021)
0 74 Domestic Manufacturing Locations (USGS, 2021)

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

U.S. consumption of calcium oxide in 2018 is estimated at 15,170 M kg. This estimate includes production of
15,202 M kg, import of 265 M kg, minus export of 295 M kg (USGS, 2021; USITC, 2021), as shown in Figure 3.

• Domestic Consumption (2018):

15,170 M kg

¦	Domestic Production (15,200 M kg)

¦	Imports for Consumption (265 M kg)

¦	Export of Domestic Production (295 M kg)

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

Trade &Tariffs

Worldwide Trade

Worldwide import and export data for calcium oxide (quicklime) are reported through the World Bank's World

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Calcium Oxide Supply Chain - Full Profile

Integrated Trade Solutions (WITS) software, as a category specific to calcium oxide. In 2021, the U.S. ranked 12th
worldwide in total exports and 9th in total imports of calcium oxide. In 2021, France 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 Oxide in 2021

2021 Worldwide Trade
Calcium Oxide (Quicklime) (HS Code 2522.10)



Top 5 Worldwide Exporters

Top 5 Worldwide Importers

France

786 M kg

Zimbabwe

1,707 M kg

Germany

749 M kg

Netherlands

537 M kg

Malaysia

506 M kg

Germany

430 M kg

Belgium

421 M kg

France

380 M kg

Vietnam

418 M kg

Australia

313 M kg

Domestic Imports and Exports

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

350
300
250
_ 200

OD

g 150
100
50
0

Domestic Trade of Calcium Oxide (Quicklime)
HS Code 2522.10

2020

I Imports from Canada
I Imports from Mexico
Imports from Other Countries

I Exports to Canada
Exports to Mexico
Exports to Other Countries

Figure 4. USITC Domestic Import and Export of Calcium Oxide 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 Oxide Supply Chain - Full Profile

Tariffs

Imports of calcium oxide are primarily supplied from Canada. There is no general duty for import of calcium
oxide, 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 Oxide

HS Code

General Duty

Additional Duty-China
(Section 301 Tariff List)

Special Duty

2522.10

None

25%

None

Market History & Risk Evaluation

History of Shortages

Calcium oxide is widely manufactured and used in a variety of industries. There were no identified calcium oxide
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 Oxide Supply Chain - Full Profile

Table 4. Supply Chain Risk Evaluation for Calcium Oxide

Risk Parameter Ratings and Drivers



1 1

1

ICriticality High

1 Likelihood Low 1

Vulnerability Low 1

Calcium oxide is widely used in water
treatment for softening and sludge
treatment. It is a precursor in the
production of calcium hydroxide
(slaked lime).

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

The U.S. is a leading producer of the
key input of calcium oxide, 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-supply-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

NSF International, 2021. Search for NSF Certified Drinking Water Treatment Chemicals, retrieved from
https://info.nsf.org/Certified/PwsChemicals/

U.S. Geological Survey (USGS), 2020. Mineral commodity Summaries for Lime, retrieved from
https://pubs.usgs.gov/periodicals/mcs2020/mcs202Q-lime.pdf

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. USITC DataWeb, retrieved from
https://dataweb.usitc.gov/

U.S. International Trade Commission (USITC), 2022. Harmonized Tariff Schedule (HTS) Search, retrieved from
https://hts.usitc.gov/current

World Integrated Trade Solutions (WITS), 2022. Trade Statistics by Product (HS 6-digit), retrieved from
https://wits.worldbank.org/trade/countrv-byhs6product.aspx?lang=en#void

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