China Nonferrous Metallurgy

Bauxite resources are a scarce mineral resource in China, with a large amount of high sulfur bauxite resources. However, the smelting of high sulfur bauxite will reduce the Al₂O₃ leaching rate, decrease the settling performance of red mud, pollute aluminum hydroxide products, and corrode production equipment. Therefore, desulfurization technology of high sulfur bauxite has become the key to achieving efficient and comprehensive utilization and alleviating the shortage of bauxite resources. At present, the desulfurization technology of high sulfur bauxite mainly includes pre-treatment desulfurization and leaching process desulfurization. Pre-treatment desulfurization includes flotation, calcination, electrochemical desulfurization, microbial desulfurization, etc. The flotation method is suitable for aluminum ore resources with low sulfur content. However, for low-grade and high sulfur aluminum ore, there are problems such as high dosage of flotation reagents and large discharge of wastewater; The desulfurization efficiency of the roasting method is high, but traditional stacking roasting has problems such as long roasting time and high energy consumption; Electrochemical desulfurization has advantages such as low temperature, atmospheric pressure, high desulfurization rate, and no secondary pollution, but there are problems such as high energy consumption and limited production scale; Microbial desulfurization has lower production costs and energy consumption, and higher environmental friendliness, but specific bacterial strains have strict requirements for growth environment and long cultivation cycle. The desulfurization process of dissolution includes oxidation evaporation desulfurization, precipitation desulfurization, and lime desulfurization. The oxidation evaporation method can remove most of S^2- from sodium aluminate solution, but its effect on the oxidation of other forms of sulfur is not significant; The precipitation method for desulfurization is relatively simple, but it has the problem of high cost of desulfurizers and difficulty in practical production; The lime method can only remove SO^2-₄ from the solution and does not have a significant removal effect on other types of sulfur ions. In the future, it is recommended to address the desulfurization problem of high sulfur bauxite in the following directions: developing low-temperature, high-efficiency, and low-energy consumption roasting processes; Improve or develop new desulfurization and capture agents; Screening efficient and easy to cultivate bacterial strains, and studying the desulfurization effect of mixed bacteria.