PROBLEM TO BE SOLVED: To provide a method for simply and efficiently coating the surface of calcium oxide particle with sulfur in a gas produced when fossil fuel is combusted to extremely suppress the hydration reaction and a method for utilizing the coated calcium oxide by elucidating the mild hydration reaction characteristics. SOLUTION: The preparation of calcium oxide particle coated with anhydrous calcium sulfate in which the hydration reactivity is extremely suppressed is carried out by collecting particles produced from a connection furnace structured by providing a high temperature preheating furnace in a rotary furnace, with a filter. In the collected particles, it is recognized that sulfur element is uniformly distributed on the surface of any of primary particles and even of aggregated particles from a surface analysis and in the consideration of the mild hydration, the surface of the calcium oxide particle is expected to be uniformly coated with anhydrous calcium sulfate and the characteristic based on the coating is applied. COPYRIGHT: (C)2011,JPO&INPIT
