Optimization of removal impurities from Fe element in concentrate rare earth elements sulfate coal of fly ash with Response Surface Methodology (RSM)

Abstract

Removal of iron impurities from rare earth element sulfate coal of fly ash concentrates has been carried out. This study aims to determine the optimum condition for the removal of impurities from the Fe element in rare earth elements concentrates with the Response Surface Method (RSM). The test was carried out to determine the effect of the independent variables (pH, temperature, and stirring rate) on the precipitated Fe element. The results showed that the optimum conditions for the precipitation of Fe element were at pH 3.5 in the first step with a temperature of 50 °C with a stirring rate of 300rpm, and after that Ca(OH)2 was used to pH 5.0 for the second step. The second-order regression model based on the RSM test shows that the square is significant, which means that the treatment given affects the response at the 95% probability level.