利用硫酸镁废液制备活性氧化镁工艺研究

硫酸法处理高镁红土镍矿过程中产生大量的硫酸镁废液,提出利用硫酸镁废液制备活性氧化镁工艺.工艺过程:采用石灰中和硫酸镁废液至pH为12左右得到氢氧化镁溶液,氢氧化镁溶液经二氧化碳微压碳化得到碳酸氢镁溶液,碳酸氢镁溶液经热解得到碱式碳酸镁沉淀,沉淀物经过滤、洗涤、干燥、焙烧得到活性氧化镁.在最佳条件下制备的活性氧化镁达到HG/T 3928-2007《工业活性轻质氧化镁》要求.采用硫酸镁废液制备活性氧化镁,一方面可以解决硫酸镁废液的治理问题,为提高高镁红土镍矿资源的综合利用率开辟一条新途径:另一方面可以制备高附加值的活性氧化镁产品.

Research on preparation of active magnesium oxide from magnesium sulphate waste water

A new process of preparation of active magnesium oxide from magnesium sulphate waste water,generated from the treatment of Mg-rich laterite-nickel ore by sulfuric acid process was introduced.Magnesium sulphate waste water was neutralized to a pH about 12 by lime to form magnesium hydroxide solution,and then carbonized by carbon dioxide under micro-pressure to get magnesium bicarbonate.Basic magnesium carbonate precipitate was obtained through thermal decomposition.Finally,active magnesium oxide was obtained from basic magnesium carbonate precipitate after filtering,washing,drying,and calcination processes,and the product indexes of active magnesium oxide met the first grade requirements in standard of HG/T 3928—2007.On the one hand,this new process could resolve the waste magnesium sulfate liquid treatment and opened up a new way of enhancing a resource utilization efficiency for the Mg-rich laterite-nickel ore.On the another hand,it could produce high value-added products.