结晶法制五水偏硅酸钠的工艺研究

Study on the Preparation of Sodium Metasilicate Pentahydrate by Crystallization Method

五水偏硅酸钠是生产超浓缩洗衣粉的主要原料之一,同时也用于餐具洗涤剂,食品工业洗涤剂,金属清洗剂以及废纸脱墨等,因此在日化领域具有广阔的应用前景。文章以泡化碱和烧碱为原料进行反应,利用结晶分离法工艺:蒸发浓缩、冷却结晶、离心分离、干燥制备产品。确定了制备过程的最佳工艺条件:溶液配料比nNa2O/S iO2模数;蒸发溶液终止浓度;冷却结晶降温速度;加入晶种;干燥温度。制备出的产品:Na2O 29.56%,S iO228.63%,Fe 0.02%,水不溶物0.12%,白度80,达到了化工行业标准的要求。

Sodium metasilicate pentahydrate is one of the main materials of super condensed laundry powder and used in dishware detergent, food industry detergent, metal detergent and waste paper deinking etc.. So it has the bright foreground in daily use chemicals. This paper introduces the method of producing sodium metasilicate pentahydrate by glass water and sodium hydroxide via evaporation,cooling crystallization, centrifugal separation, and the optiumum conditions were determined,including the molar ratio of Na2O to SiO2, the final evaporation temperature, the speed of temperature drop in cooling crystallization, crystal seed added and drier temperatuer. The quality of production prepared by this method is as follows：Na2O 29.56%, SiO2 28.63%, Fe 0.02%, water- insoluble substance 0.12% ,brightness 80,and it reaches the standard of chemical industry grade.