Abstract:A method of recovery of alumina from coal fly ash (CFA) is reported in this article. The method includes activation of CFA by calcination with CaCl2, followed by washing with water to recover unreacted CaCl2 and leaching with sulfuric acid. The technological conditions which were considered to be key factors for the success of the procedure, including calcination temperature, calcination time, CaCl2 dosage, sulfuric acid concentration and leaching time, were investigated. The experimental results indicate that calcination with CaCl2 can effectively decompose the corundum and mullite particles, which can hardly be broken down by mineral acid leaching. When mixed with CaCl2 at a ratio of 0.8:1 (CaCl2:CFA) and the mixture calcined at 900℃ for 30min, the recovery of alumina can reach as high as >95% by sulfuric acid leaching.
梁振凯, 雷雪飞, 孙应龙, 徐辉, 王毅. 氯化钙焙烧法提取粉煤灰中的氧化铝[J]. 中国环境科学, 2013, 33(9): 1601-1606.
LIANG Zhen-Kai, LEI Xue-Fei, SUN Ying-Long, XU Hui, WANG Yi. Extraction of alumina from coal fly ash by calcination with calcium chloride process. CHINA ENVIRONMENTAL SCIENCECE, 2013, 33(9): 1601-1606.