Developing a CO2-free process to produce Portland cement, the exact same material that the industry uses today.

Sign up for daily news updates from CleanTechnica on email. Or follow us on Google NewsSeveral years ago I concluded that Cement’s CO2 Emissions Are Solved Technically, But Not Economically. Since then I’ve had numerous conversations with deep experts on the subject that made me realize that it wasn’t just cost, but regulations that held alternatives back.I’m digging through some of the current crop of alternatives in this mini-series on the subject. Recently, I assessed Sublime Systems’ electrolysis approach, which electrolyses water into oxygen and hydrogen, plays with the ionic chemistry and pH balances, and feeds any lime bearing substance in crushed form through it, including limestone, concrete and electric arc furnace slag.Another thread that was handed to me was California’s Brimstone, which takes a different, less technically avante garde approach.Let’s start with why cement is a problem in terms of climate change. Its primary ingredient is calcium oxide, known as quicklime or lime, with former being more specific and the latter good enough in context. That’s made today by heating limestone to several hundred degrees Celsius in kilns

Brimstone was selected for a $189 million investment by the U.S. Department of Energy’s Industrial Demonstrations Program to decarbonize cement.