QUICK LIME-CONTAINING POWDER AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To produce a quick-lime containing powder which has an increased quick lime content as compared with that of the intermediate stage product by classifying an intermediate stage product withdrawn from a suspension preheater in a cement production process and picking out a fine particle fraction. SOLUTION: The above cement production process comprises: mixing raw materials, i.e., limestone, clay, siliceous stone and iron oxide in an appropriate ratio to obtain a raw material mixture; subjecting the raw material mixture to drying and fine pulverization with a raw material mill to form a cement raw material; firing the cement raw material with a suspension preheater kiln provided with a cyclone type suspension preheater placed upstream from a rotary kiln to form cement clinker; adding gypsum to the cement clinker; and pulverizing the resulting mixture with a finishing mill to produce a cement product. The production process of this quick-lime containing powder comprises: withdrawing a portion of an intermediate stage product which is preheated by the suspension preheater in the above cement production process and contains quick lime converted from limestone in the cement raw material through this preheating, from the preheater prior to entering in the intermediate stage product into the rotary kiln; and subjecting the withdrawn intermediate stage product to centrifugal classification, wherein, by setting the boundary particle size of particle classification to an appropriate value, most of the quick lime particles having fine particle size and low density are collected on the fine particle fraction side to produce the objective quick-lime containing powder having a quick lime content enhanced up to >=60% as compared with an about 40% quick lime content of the intermediate stage product.