GB519770A - Improvements in and relating to the manufacture of cement - Google Patents

Abstract

519,770. Cement. RITTER PRODUCTS CORPORATION. July 1, 1938, No. 19558. Convention date, July 3, 1937. Drawings to Specification. [Class 22] . In the treatment of minerals used for the manufacture of cement, finely divided solid mineral material containing calcium carbonate and silica is separated by, the action of an electrostatic field into groups which contain more carbonate and more silica than the original material. If the, material also contains aluminium oxide, a third group containing more aluminium oxide than the original material is also separated at the same time. The group 'containing calcium carbonate is further separated by an electrostatic field into concentrates and middlings containing more and less carbonate than the original group and the middlings may be returned for re-. treatment with the raw material. The material may be subjected to the action of a plurality of electrostatic fields preferably in the apparatus described in Specification 519,817, [Group II]. Before the electrostatic separation, dust may be removed from the finely divided raw material and itself subjected to electrostatic separation. The rejects, from the main separation may be roasted, subjected to magnetic separation and the dust removed therefrom. Some or all of the separated portions of raw material are mixed together in any desired proportion for the production of cement and ground.