MODELING OF PROCESS PARAMETERS AND ANALYSIS OF EFFECT OF VARIABLES IN THE DEAD BURNING OF MAGNESITE IN ROTARY KILN

The challenges of improving sintered MgO raw materials with special high temperature properties demand higher temperature calcination. In the process of dead burning of magnesite (DBM) in rotary kiln, the heat expenditures were found to be mainly due to dead burning of magnesite, loss through exhaust gases, loss through kiln shell by radiation & convection, clinker exit etc. The calcination process is highly energy intensive and involves various interdependent variable factors. An attempt was made to build a model and a screening design of experiment was performed with few process variables to identify the greatest effect of variables on the response quality. The design variables chosen were raw magnesite (RM) feed rate, kiln rotation (RPM), fuel consumption and burning zone temperature (BZT). The response variables were exit gas temperature and density of dead burnt magnesite (DBM). A fractional factorial design was used to keep the number of experimental runs to a minimum. ANOVA and normal plots were used to evaluate the effects of different variable factors on the sensory/response properties. The Experimental Design, ANNOVA, Response surface etc. given an insight of dead burning of magnesite in rotary kiln. This work had enabled us to correlate the BZT, RPM, RM feed with the exit gas temp and density of magnesite produced. The result opens up an avenue to look into the optimum region of operations within the ranges of variables considered in order to minimize the exhaust gas temp. and to maximize the density of the DBM produced.