Microstructure study of lime-slag cement stone after thermal treatment at various temperatures

For the time being the problem of metallurgie waste utilization has obtained urgent importance. The slags of aluminothermic manufacturing of metallic chromium and ferrotitanium are considered to be the most promising component of thermally resistant lime-slag concretes. Fine dispersion particles of aggregates made of such slags participate in a hydration reaction in presence of alkali. This phenomenon allows for the prediction of hydration occurrence on the surface of coarse aggregate of the aluminothermic manufacturing process of metallic chromium and ferrotitanium to enhance cohesion between the aggregate and the cement stone. The paper reports on a study of the phase composition and the microstructure of lime-slag cement stone with the addition of the slags of metallic chromium and ferrotitanium after a thermal treatment at various temperatures. It has been observed that metallic chromium and ferrotitanium slag additives increase the highest admissible operation temperature of thermally resistant lime-slag concretes. Such effect is obtained due to refractory compounds formation on the aggregate surface. (paper)