Producer
Washington Mills
The oldest continuously operating abrasive grain company in the US (founded 1868). Washington Mills acquired the Carborundum Company's electro minerals silicon carbide plant in Niagara Falls, NY in 1986. Expanded with a second SiC plant in Hennepin, IL in 2023 (+10,000 t/yr), bringing total SiC crude capacity to approximately 70,000 tonnes/year across both US plants — making it the largest SiC abrasive grain producer in North America. Produces CARBOREX® brand black and green SiC for abrasive blasting, grinding wheels, lapping, wiresawing, filtration, and refractory applications.
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Goods downstream
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Stories
What they make
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Where they make it
2 facilities
Washington Mills Hennepin SiC Plant →
USHennepin, Illinois · manufacturing
Second US SiC furnace plant; expanded in 2023 adding ~10,000 t/yr, bringing Washington Mills total SiC crude capacity to ~70,000 t/yr across Niagara Falls and Hennepin. Expansion was partly driven by US onshoring trends and tariff pressure on Chinese SiC.
Washington Mills Niagara Falls SiC Plant →
USNiagara Falls, New York · manufacturing
Acquired from The Carborundum Company (a historic SiC pioneer) in 1986. Produces CARBOREX® SiC crude ore via Acheson electric furnace process plus final grains and powders. Niagara Falls location historically chosen for cheap hydroelectric power — the Acheson SiC process is extremely electricity-intensive (~7-10 MWh per tonne of SiC). This plant represents direct continuity of the original Carborundum Company operations (founded by Edward Acheson near Niagara Falls in 1891).
What else they do
Business segments
The company's full revenue map, where this supply-chain role fits within their broader business.
Fused Aluminum Oxide (Alumina)
42%Silicon Carbide Abrasive Grain
25%Specialty Fused Minerals
20%Garnet & Natural Abrasives
13%
Intelligence
What's known
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Did you know2022
Washington Mills' boron carbide (B4C) product line connects an abrasive grain company to nuclear energy and body armor markets in ways that are invisible from the outside. Boron carbide is the third-hardest known material (after diamond and cubic boron nitride) and is a primary neutron absorber in nuclear reactor control rods and spent fuel storage pools — the material that physically stops chain reactions. The same boron carbide that Washington Mills sells as an abrasive lapping compound for ultra-hard ceramic grinding is also the material used in nuclear reactor safety systems and in NIJ Level IV body armor plates (B4C/SiC composite ceramic inserts). Washington Mills is one of a small number of Western producers of boron carbide powder, making it a minor but genuine defense-industrial and nuclear supply chain participant alongside its industrial abrasives identity.
Washington Mills ↗Origin2022
Washington Mills, founded in 1868 and still privately held (family-owned through the Corrow family for generations), is one of the oldest continuously operating manufacturers in the United States and a direct descendant of the original carborundum/abrasive industry that grew up around Niagara Falls in the late 19th century. The company's original location near Niagara Falls was not accidental: electric arc furnace fusion of bauxite into aluminum oxide requires 4,000-6,000 kWh of electricity per ton, and proximity to Niagara Falls hydroelectric generation made New York and Ontario the natural home of the North American abrasives industry. Washington Mills has survived two world wars, the Great Depression, and deindustrialization of American manufacturing by serving industrial markets that cannot easily offshore: abrasive grains for precision grinding, lapping, and polishing that must meet tight size distribution specifications and be delivered reliably to domestic manufacturers. Their North Grafton, Massachusetts headquarters has shipped abrasive grain continuously since the McKinley administration.
Washington Mills ↗