Zhang L.-Q.,Shenyang University of Chemical Technology |
Zhang L.-Q.,Liaoning Provincial College |
Yuan B.-F.,Shenyang University of Chemical Technology |
Yuan B.-F.,Liaoning Provincial College |
And 6 more authors.
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2014
Magnesium sulfate and ferrous sulfate were extracted by ethanol crystallization from sulfuric acid-leached solutions of a low-grade ludwigite, and then boric acid was extracted by low temperature crystallization, therefore the co-extraction of boron, magnesium and iron in low-grade ludwigite was realized. The feasibility of the extraction of magnesium sulfate and ferrous sulfate crystals from the solution using ethanol was discussed theoretically. The effects of pH, ethanol used percentage, and crystallization temperature on the crystallization ratio of magnesium sulfate and ferrous sulfate in ethanol-water were investigated. The results show that when the solution pH is around 2, the volume ratio of solution to ethanol is 1:1.5, and the crystallization temperature is room temperature, the highest crystallization yields of 97.73% and 97.86% for magnesium sulfate and ferrous sulfate were observed and the purities are 99.10% and 98.48%, respectively. The recovery ratio of boric acid is 74.66%, and the purity is 99.70%. The content of the impurities, magnesium and iron, in the recycled boric acid are 1.34×10-3% and 8.54×10-3%, respectively. The merits of this technology include relatively mild operating condition, lower energy consumption, higher extraction ratio and the recoverability of ethanol by distillation. Source