Sustainable Mining and Metallurgy

High concentration sodium metaaluminate solution will be produced when invalid catalyst is recovered by alkali method. The leaching solution has significant recovery value because of its high aluminum content and less impurities. In this paper, sodium metaaluminate was converted into aluminum hydroxide precipitation by carbon separation to recover aluminum. Response surface methodology was used to study the significance of CO₂ ventilation rate, aeration time and dilution ratio on the conversion rate of Al(OH)₃ precipitation, and to explore the best process parameters of aluminum hydroxide precipitation. The results show that the average precipitation conversion rate of Al(OH)₃ is 98.59% with the CO₂ aeration rate of 0.360L/min, the aeration time of 116min, and the dilution ratio of 4 times. The precipitation process is controlled by many factors, among which the aeration time and dilution ratio have significant effects on the precipitation conversion of Al(OH)₃.