Redesigning Raw Materials Mixture Burning Behavior and Effect on Portland Cement Productivity

A burnability study has been carried out to determine the effect of homogeneity and particle size on clinker reactions to ensure constant product quality and consistent and uninterrupted operation of the kiln. After verifying the raw materials suitability for the Portland cement chemically manufacture, the raw mix design criteria were the lime saturation factor LSF = 98%, silica ratio SR = 2.4, alumina ratio AR= 1.8, hydraulic module HM = 1.98, degree of sulfurization DOS = 0.61, liquid phase L.PH at (1338°C = 26.3, 1400°C = 30.7, 1450°C = 31.2), and free lime (FL)= 1.2, the raw mixture was designed according to a method of lime saturation factor and the mixing ratios were as follows: 67.63% limestone and 32.37% clay. The raw materials were processed and prepared to obtain three samples with a particle size of less than 75µ using a ceramic ball mill with a mixture of high homogenization, one sample of which is approximately 89% passing from a sieve 90µ using the handed homogenization method, for each sample weigh 100 gm of the raw material mixture. In this study, burnability for the raw meal was done at 1350, 1400, and 1450ºC with time retention on maximum temperature from 90 to 120 min using a laboratory muffle furnace. Four burning tests were conducted; the first test T1 used the residual raw mixture on a 90µ sieve of 11% at a temperature of 1450°C and the three tests; T2, T3, and T4 used the residual mix on a 45µ sieve of 35%, with a change in the final temperature; 1450, 1350, and 1400 ºC respectively. Traces of unreacted free lime (FL) are detected, as an indicator of burnability; T1 = 1.91, T2 = 2.48, T3 = 1.5, and T4 = 1.27. The study has shown that homogeneity and particle size of the raw mix plays a crucial role in energy usage, kiln performance, clinker production, and the quality of cement.