Process to make calcium oxide or ordinary Portland cement from calcium bearing rocks and minerals

(22) 24.08.2022

(43) 29.12.2022

(57) Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

(71) California Institute of Technology, Pasadena, CA (US); Brimstone Energy Inc., Oakland, CA (US)