School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.
School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.
Water Res. 2017 Nov 15;125:318-324. doi: 10.1016/j.watres.2017.08.047. Epub 2017 Aug 22.
This study investigates an environmentally friendly technology that utilizes waste by-products (waste acid and waste alkali liquids) to treat mineral processing wastewater. Chemical precipitation is used to remove silicate from scheelite (CaWO) cleaning flotation wastewater and the waste by-products are used as a substitute for calcium chloride (CaCl). A series of laboratory experiments is conducted to explain the removal of silicate and the characterization and formation mechanism of calcium silicate. The results show that silicate removal reaches 90% when the Ca:Si molar ratio exceeds 1.0. The X-ray diffraction (XRD) results confirm the characterization and formation of calcium silicate. The pH is the key factor for silicate removal, and the formation of polysilicic acid with a reduction of pH can effectively improve the silicate removal and reduce the usage of calcium. The economic analysis shows that the treatment costs with waste acid (0.63 $/m) and waste alkali (1.54 $/m) are lower than that of calcium chloride (2.38 $/m). The efficient removal of silicate is confirmed by industrial testing at a plant. The results show that silicate removal reaches 85% in the recycled water from tailings dam.
本研究探讨了一种环保技术，利用废副产品（废酸和废碱液）处理选矿废水。采用化学沉淀法从白钨矿（CaWO）精选浮选废水中去除硅酸钠，废副产品用作氯化钙（CaCl）的替代品。进行了一系列实验室实验，以解释硅酸钠的去除以及硅酸钙的特性和形成机制。结果表明，当 Ca:Si 摩尔比超过 1.0 时，硅酸钠的去除率达到 90%。X 射线衍射（XRD）结果证实了硅酸钙的特性和形成。pH 值是硅酸钠去除的关键因素，随着 pH 值的降低形成聚合硅酸可以有效提高硅酸钠的去除率并减少钙的用量。经济分析表明，废酸（0.63 美元/立方米）和废碱（1.54 美元/立方米）的处理成本低于氯化钙（2.38 美元/立方米）。在工厂的工业测试中证实了硅酸钠的高效去除。结果表明，尾矿坝回用水中硅酸钠的去除率达到 85%。
