元明粉母液生产一水硫酸镁的工艺研究

Study on process for preparation of magnesium sulfate monohydrate by mother liquid of sodium sulfate

以元明粉母液和六水氯化镁为原料,根据Na+,Mg2+//C l-,SO42-.H2O四元相图,生产一水硫酸镁和氯化钠,确定了最佳工艺条件:配料时元明粉母液过量10%;反应温度为55℃;蒸发温度为100℃;蒸发溶液终点密度为1.326 g/cm3。在小试验基础上进行了放大实验,结果表明:产品一水硫酸镁达到Q/YHJ-03-022-2004一水硫酸镁优等品指标;产品氯化钠达到GB 5462—1992工业盐指标。此工艺使影响元明粉产品质量的母液及其杂质氯化镁都得到了合理利用,同时也解决了元明粉公司由于每年盐池自然产的硫酸镁产量受到限制,从而使一水硫酸镁产量无法扩大的问题。

Based on quaternary phase diagram of Na^＋ , Mg^2＋//Cl^- , SO4^2- · H2O, magnesium sulfate monohydrate and sodium chloride were prepared by using mother liquid of sodium sulfate and magnesium chloride hexahydrate as raw materials. Optimized and optimium conditons were confirmed as follows：mother liquid of sodium sulfate was 10% overdosed, reaction temperature was 55 ℃, evaporation temperature was 100 ℃, and endpoint density of evaporating liquid was 1. 326 g/cm^3. Scale - up experiment was carried out on the basis of lab experiment. Results showed that magnesium sulfate monohydrate product was up to the top grade of magnesium sulfate monohydrate of Q/YHJ -03 -022 -2004 and soldium chloride product met GB 5462-1992. In this process, mother liquid of sodium sulfate and impurity magenium chloride that affact the quality of sodium sulfate product were both effectively utilized, and the problem of low yield of magnesium sulfate monohydrate due to limited natural production of salt pond in sodium sulfate companies was resolved as well.