Application of microwave for promoting biooxidation of refractory high-sulphide concentrates: influencing factors analysis

Abstract

ABSTRACTTo promote biooxidation efficiency of a refractory high-sulphide gold concentrate, microwave technology has been applied. Two factors were investigated in the microwave stage including initial solution pH and microwave irradiation time. The results show that biooxidation efficiency of the gold concentrate increases with the increasing initial solution pH. The effect of microwave irradiation on biooxidation efficiency becomes negligible after 300 s. The optimal experiment conditions were initial solution pH of 7.00 and microwave irradiation time of 300 s. Using the irradiated sulphide concentrate, the biooxidation period decreased and the biooxidation efficiency increased. After microwave irradiation, the mineral particle surface was destroyed and became bumpy. Microwave contributed to the decrease of mineral particle size and the increase of specific surface area. A mechanism model shows that the increasing mineral surface area caused by microwave irradiation leads to the enhancement of biooxidation efficiency.