Removal of Alkalies from Portland Cement Kiln Dust

摘要

Ten to twelve million tons of dust is produced by cement kilns annually in the United States, resulting in a serious waste disposal problem. The Bureau of Mines investigated two alkali volatilization methods for converting this dust into materials for making portland cement and a useful potassium product. Portland cements with 28-day strengths above 5,000 psi were produced from low-alkali residues using sintering and melting methods. For nearly complete removal of alkalies, primarily potassium sulfate, from cement kiln dust, a temperature above 1,300 deg C and a reducing atmosphere were required.