A Study on the Manufacture of Clinker Using Low Grade Limestone and Waste Paper Sludge

Abstract

This study was carried out to manufacture portland cement clinker using low grade limestone and waste paper sludge. Waste paper sludges were added to supply CaO component in low grade limestone, because low grade limestone contains relatively poor CaO. The cement raw materials such as limestone, clay and iron-ore were obtained in Ssangyong cement in Donghae, waste paper sludge in Samil paper. Composition and texture of raw materials and cement mineral phases were investigated by XRF, XRD and DTA etc..
Portland clinker was made as follows. Modulus of mixture of raw materials was fixed in LSF = 94.0, SM = 2.4 and IM = 1.7. Raw materials are crushed, mixed and ground to fine powder, then put into furnace where it is heated to burning temperature. In here, CaF₂ as a fluxing agent was used to facilitate burning.
From the experimental results it appears CaF₂ promotes that produces C₂S at relatively low temperature of 1, 100°C. Cement minerals were produced as C₂S at 1, 100°C and C₃S at 1, 200°C. Also it was found that when water is added to cement minerals, there follows formation of cement hydrates such as C-S-H and ettringite.