Ep.3 Solving a Sustainability Problem: This company finds utility in unusable waste

Supplementary cementitious materials, or SCMs, have completely transformed the global cement industry. Where Portland cement once enjoyed a near monopoly in the industry, it’s now rapidly losing market share to all kinds of blended solutions using SCMs, which replace a large percentage of the cement clinker – that’s limestone and clay, cooked in a kiln at a balmy 1500 degrees Celsius – that goes into making concrete. The biggest examples of SCMs are fly ash, which is the byproduct from coal mining, and blast furnace slag, the byproduct from steel production.

There’s just one issue: the steel industry is cleaning up its own act. Instead of melting pig iron in a coal-fired blast furnace, big steel makers have made the shift to electric arc furnaces. Now, this isn’t a problem in the strictest sense; electric arc furnaces emit significantly less carbon into the atmosphere. But the slag yield from this newer, cleaner production process, creates an inferior and chemically inert SCM. It’s a new form of waste, and it has no place to go.

Carbon Upcycling has a solution. The company has established a waste-to-value supply chain by turning something very few industrialists were paying attention to, into a sustainable feedstock. The company’s CEO, Apoorv Sinha, says he wants to convert industrial waste in virtually all forms into sustainable feedstocks. But you gotta start somewhere, and somewhere, in this case, is the global cement industry.