PureCal

Dominican calcium carbonate for American industry.

PureCal is building a supply of calcium carbonate for makers of food, pharmaceuticals and solar glass, from its deposit in the Dominican Republic to its plant in Wilmington, Delaware.

Contact PureCal See how it works
Map: the Dominican Republic and Wilmington, Delaware The Dominican Republic, on the island of Hispaniola in the Caribbean, is shaded. A dotted route runs north across the Atlantic to Wilmington, Delaware, on the Delaware River, and a ship moves along it. Wilmington, Delaware Dominican Republic Atlantic Ocean Caribbean Sea
Route shown for illustration.

How it works

Four steps take the mineral from the ground in the Caribbean to a buyer's loading dock on the East Coast.

  1. The deposit

    Calcium carbonate rock comes from PureCal's deposit in the Dominican Republic.

  2. The crossing

    The rock ships north to the U.S. East Coast. Container lines already sail between Dominican ports and the East Coast; one carrier lists three days from Haina to Port Everglades, Florida.1

  3. The plant

    In Wilmington the rock will be ground, sized, dried and tested to each customer's specification.

  4. The customer

    Finished grades go to food, pharmaceutical and glass makers, each lot with its own laboratory report.

The mineral

Calcium carbonate, CaCO3, is one of the most familiar minerals there is. The work lies in making it clean, fine and consistent.

Calcite, the common form of calcium carbonate, is the main mineral in limestone and marble. Chalk is a less compacted relative of limestone, and corals and shellfish build their shells and skeletons from calcite and aragonite, two forms of calcium carbonate.2,3

It reaches buyers in two ways. Ground calcium carbonate is natural rock, crushed and milled to size. Precipitated calcium carbonate is made in a chemical plant, by burning limestone into lime and then adding carbon dioxide back.3,4 PureCal's product is the ground kind.

Making it is careful mechanical work. The stone is quarried, washed and cleaned of impurities, ground, sorted by particle size and dried. Some grades also receive a thin surface coating.3

Buyers order to a written specification: how much of the material is calcium carbonate, how fine and bright it is, and how little iron, lead and arsenic it carries. The three standards below set the floor for food and medicine.

How pure the standards require it to be

Minimum calcium carbonate content, percent by weight5,6,7

Horizontal ranges on a scale from 90 to 101 percent. FDA ground limestone for food: at least 94 percent. FAO/WHO food additive specification: at least 98.0 percent. U.S. Pharmacopeia: 98.0 to 100.5 percent.90%92%94%96%98%100%FDA, ground limestone for food21 CFR 184.1409FDA, ground limestone for food: at least 94%at least 94%FAO/WHO food additive specINS 170(i), after dryingFAO/WHO food additive spec: at least 98.0%at least 98.0%U.S. Pharmacopeiacalcium carbonate monograph, after dryingU.S. Pharmacopeia: 98.0% to 100.5%98.0% to 100.5%FDA ground limestone for food: at least 94 percent. FAO/WHO food additive specification: at least 98.0 percent. U.S. Pharmacopeia: 98.0 to 100.5 percent.90%94%98%100%FDA, ground limestone for food21 CFR 184.1409at least 94%FAO/WHO food additive specINS 170(i), after dryingat least 98.0%U.S. Pharmacopeiacalcium carbonate monograph, after drying98.0% to 100.5%

The food additive specification also caps lead and arsenic at 3 mg/kg each and fluoride at 50 mg/kg.7

Show as a table
StandardCalcium carbonate content
FDA, ground limestone for food (21 CFR 184.1409)At least 94%
FAO/WHO food additive specification (INS 170(i))At least 98.0%, after drying
U.S. Pharmacopeia, calcium carbonate98.0% to 100.5%, after drying

Who it is for

PureCal starts with the customers who care most about purity, then adds the larger filler markets.

Food and supplements

Calcium carbonate is one of the two most common forms of calcium in dietary supplements, and it is 40% calcium by weight.8 FDA allows ground limestone in food with no limit other than good manufacturing practice.5

Pharmaceuticals

In tablets it serves as a filler, a buffer, a fast-dissolving agent and an opacifier.9 Pharmaceutical buyers qualify suppliers against the U.S. Pharmacopeia monograph.6

Solar glass

Solar panels sit behind ultra-clear glass, and limestone is one of its raw materials, about 117 kg per tonne of glass in one recent study. Iron reduces how much sunlight the glass lets through, so Chinese standards cap iron oxide in ultra-white solar glass at 150 parts per million.10

Plastics, paint and paper

It improves breathable plastic films and reinforces PVC building profiles and flooring. It is also a filler and coating in paper, and a paint filler that can replace part of the titanium dioxide.4 PureCal plans to serve these markets later.

The same mineral, in other grades, neutralizes acid farm soils, scrubs sulfur from power-plant exhaust and conditions drinking water.11,12,13

The Dominican Republic

The country covers the eastern two-thirds of Hispaniola, the island it shares with Haiti.14 Much of it is limestone.

About one-third of the country is carbonate rock, according to the national geological survey, and limestone deposits are mapped in Pedernales, San Cristóbal, Barahona and Puerto Plata.15 The Caribbean coastal plain runs about 240 km along the south coast, and its stepped marine terraces are made mainly of reef limestone. In the northeast, the Los Haitises karst is cut by sinkholes more than 500 m across.16

Mining is an established industry here: gold and silver at Pueblo Viejo, ferronickel at Falcondo, copper at Cerro de Maimón, and the island's own blue larimar and amber.15 Calcium carbonate already moves north: in its 2021 report, the national mining directorate listed the start of calcium carbonate exports to the United States, alongside a US$8 million rehabilitation of the port at Barahona.17

The CAFTA-DR free trade agreement took effect for the Dominican Republic on March 1, 2007, and in 2025 about half of Dominican exports, by value, went to the United States.18,19 Container lines publish sailings of two to four days from Dominican ports to Florida and Georgia.1

Capital
Santo Domingo
Area
About 48,000 km² (18,600 sq mi)14
Population
11.5 million (2025)20
Highest point
Pico Duarte, about 3,100 m, the highest mountain in the West Indies21
Language
Spanish
Currency
Dominican peso
Mining law
Law 146 of 1971, under the Ministry of Energy and Mines22
Map: trucks leaving a plant in Wilmington, Delaware A map of the United States. Trucks pull out of a plant in Wilmington, Delaware, one after another, and travel to New England, Ohio, Tennessee, Florida, Texas and Utah. New England Ohio Tennessee Florida Texas Utah Wilmington,Delaware
Routes shown for illustration.

Wilmington, Delaware

A port city with two centuries of chemistry behind it.

Wilmington's port sits on the Delaware River, 65 miles from the Atlantic. The State of Delaware has owned it since 1995, and Enstructure has run it since 2023. It handles containers, perishables, bulk cargo, roll-on/roll-off cargo and project cargo.23

E.I. du Pont began building his gunpowder mills on the Brandywine, near Wilmington, in 1802.24 Chemical manufacturing is still Delaware's largest manufacturing industry.25

More than 52 million people live within 250 miles of northern Delaware,26 and Interstate 95 runs through Wilmington.27 That puts the plant close to buyers across the Northeast and Mid-Atlantic.

Contact

If you buy calcium carbonate, test it or ship it, Jay Snyder would like to hear from you.

j.snyder@purecal.com

Notes and sources

  1. Dominican Republic schedule, Crowley (July 2025); Crowley Puerto Plata service (May 17, 2018); ONE AL5 schedule (May 2020). www.crowley.com
  2. Calcite and aragonite. Common Minerals, University of Minnesota. commonminerals.esci.umn.edu
  3. What is calcium carbonate; Calcium carbonate production. British and Irish Calcium Carbonates Federation. calcium-carbonate.org.uk
  4. Calcium carbonate: GCC and PCC. Imerys. imerys.com
  5. 21 CFR 184.1409, Ground limestone. Electronic Code of Federal Regulations. www.ecfr.gov
  6. Calcium Carbonate monograph. USP-NF. doi.usp.org
  7. Calcium carbonate, INS 170(i). FAO/WHO Joint Expert Committee on Food Additives (JECFA) specification. www.fao.org
  8. Calcium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  9. Ambrogi, V., et al. Pharmaceutics 15(1), 2023. www.mdpi.com
  10. Chowdhury, et al. Sustainable Energy & Fuels 9(6), 2025. pubs.rsc.org
  11. Liming materials for Minnesota soils. University of Minnesota Extension. extension.umn.edu
  12. Flue gas desulfurization fact sheet, EPA-452/F-03-034. U.S. EPA. www.epa.gov
  13. Optimal corrosion control treatment, EPA 816-B-16-003. U.S. EPA. www.epa.gov
  14. Dominican Republic. Encyclopaedia Britannica. www.britannica.com
  15. García Cocco, E. Potencial minero de la República Dominicana. Servicio Geológico Nacional, March 2023. uteco.edu.do
  16. Díaz de Neira, J.A., et al. Boletín Geológico y Minero 128(3), 2017. info.igme.es
  17. Memoria Institucional 2021. Dirección General de Minería. mineria.panel-dev-pys.ogtic.gob.do
  18. Dominican Republic. Office of the U.S. Trade Representative. ustr.gov
  19. Dominican exports in 2025, ProDominicana data. El Dinero, January 14, 2026. eldinero.com.do
  20. Dominican Republic, population. World Bank. data.worldbank.org
  21. Duarte Peak. Encyclopaedia Britannica. Published heights range from 3,087 m to 3,175 m. www.britannica.com
  22. 2016 Minerals Yearbook, Islands of the Caribbean. U.S. Geological Survey. pubs.usgs.gov
  23. Port of Wilmington, port history and overview. Diamond State Port Corporation. port.delaware.gov
  24. Brandywine River powder mills, Landmark 221. ASME. www.asme.org
  25. Science and technology in Delaware. Delaware Prosperity Partnership. www.choosedelaware.com
  26. Location. Delaware Prosperity Partnership. choosedelaware.com
  27. DelDOT marks end of I-95 Restore the Corridor project. State of Delaware News, April 6, 2023. news.delaware.gov