SUBLIME CEMENT
Company:
Sublime Systems
Location:
Holyoke, Massachusetts
Products:
Cement
Technology:
The process is an Electrochemical process (electrolyzer) at ambient temperature (100C). The feedstock, calcium silicate rocks or industrial wastes, are broken down into their constituent minerals, and the cementitious minerals are separated into calcium and silicates and reassembled into reactive ingredients for Sublime Cement®.
Meets ASTM C1157, the performance specification for hydraulic cement.
Benefits:
Up to 90% reduction in CO2 emissions vs. OPC. Non-cementitious minerals such as magnesium, iron and aluminum can be produced at a high purity and sold as commodities. A one-to-one replacement for OPC. It appears to be highly scalable. Other commodity minerals may be a byproduct.
Possible disadvantages:
Cost of electric power for the process. Loss of $87 million dollar award from DOE in 2025 has stopped any work on their planned commercial scale facility. Using average U.S. grid for electric processing power reduces C02 emission reductions to about 60% vs 90% for green energy assumed.
Status:
First commercial pour was made in 2024 by Turner Construction for a slab on grade. Has relationships with Siam Cement Group in Thailand, CRH, and Holcim. 2023 LCA showed emissions of 72 kgCO2/Mt.
TRL estimated at 7.
Production:
Currently produce 250 Mt/year at Somerville, MA, pilot plant. Won a DOE award in 2024 to finance part of their first 30,000 Mt/yr commercial facility in Holyoke - funding was taken away in late 2025. Megaton (1,000,000 Metric tons) production plant goal is 2028 - this would require about 1.35 GW hours of electricity (total US renewable power at 373 GW in 2024).