Optimization of process parameters for producing graphite concentrate using response surface methodology

The optimization of process parameters for the production of a graphite concentrate was developed using response surface methodology (RSM). The relationship between the responses, i.e. total carbon grade and recovery, and four process parameters, i.e. kerosene dosage, sodium silicate dosage, agitation speed and scrubbing time were presented as empirical model equations for graphite concentration. The model equations were then optimized using the quadratic programming method to maximize total carbon grade and recovery within the experimental range studied. The optimum conditions were found to be 680 g/t kerosene, 500 g/t sodium silicate, 1500 rpm agitation speed and 75 min scrubbing time to achieve the maximum total carbon grade. The model prediction of 94.9% total carbon grade at these optimum conditions is higher than any value obtained in the experiments conducted. Similarly, the conditions for maximum total carbon recovery were found to be 807 g/t kerosene, 162 g/t sodium silicate, 987 rpm agitation speed and 36 min scrubbing time. The model prediction of 96.4% total carbon recovery at these optimum conditions is also higher than any value obtained in the experiments conducted. This study indicates that the response surface methodology was useful in improving the production of graphite concentrate. (C) 2007 Elsevier B.V. All rights reserved.