硫酸法处理粉煤灰制备冶金级氧化铝

Preparation of Metallurgical Alumina from Coal Ash with Sulfuric Acid Process

对硫酸法处理循环流化床粉煤灰制备冶金级氧化铝进行研究。结果表明,在180℃、时间5h、硫酸初始质量浓度30%、酸过量系数1.5的条件下,粉煤灰中氧化铝的溶出率达到93.1%。以500～600℃烧结40min的粉煤灰为调碱剂,利用高锰酸钾沉淀法对硫酸铝粗液的除铁率达到91.7%。硫酸铝精液浓缩结晶后在1 100℃煅烧4h,即可得到满足YS/T 274-1998标准1级要求的冶金级氧化铝。

Preparation of metallurgical alumina from coal ash in circulating fluidized bed with sulfuric acid method was studied. The results show that the A12 03 leaching rate reaches 93.1% under the optimum con- ditions including temperature of 180 ℃, time of 5 h, initial sulfuric acid mass concentration of 30%, and acid excess coefficient of 1.5. The iron removal rate from crude aluminum sulfate solution is 91. 7% by KMnO4 oxidation precipitation method with coal ash calcined at 500~600 ℃ for 40 rain as alkaline agent. The refined aluminum sulfate solution is concentrated, crystallized, and calcined at 1 100 ℃ for 4 h to pro duce metallurgical alumina which meets YS/T 274--1998 standards, level 1.