海水淡化浓盐水联产烧碱、纯碱工艺

Process of producing Caustic Soda and Soda Ash from Concentrated Brine of Seawater Desalination

结合沿海淡水、土地缺乏情况,提出以海水为原料,采用反渗透、纳滤海水淡化得到淡水、淡盐水和浓盐水;浓盐水蒸发、除镁得到轻质碳酸镁产品和除镁母液,除镁母液循环至纳滤;淡盐水蒸发浓缩、空气吹溴、净化得到精制盐水、氢氧化镁和碳酸钙;精制盐水离子膜电解、合成得到液体烧碱产品和氯化氢;精制盐水吸氨碳酸化得到重碱和重碱母液,重碱煅烧得到纯碱产品;重碱母液与氯化氢反应得到脱氨母液,脱氨母液高温蒸发得到精制盐和制盐母液,制盐母液低温蒸发得到氯化铵产品和制铵母液,精制盐循环至淡盐水蒸发浓缩或成为产品。

Considering the shortage of coastal fresh water and land,it is proposed to use seawater as raw material,and use reverse osmosis and nanofiltration to desalinate seawater to obtain fresh water,light salt water and concentrated brine.Light magnesium carbonate product and mother liquor of magnesium removal are obtained by evaporation and magnesium removal of concentrated brine,and the mother liquor of magnesium removal is recycled to nanofiltration;The refined brine,magnesium hydroxide and calcium carbonate are obtained by evaporation and concentration of light brine,air blowing bromine and purification;Liquid caustic soda products and hydrogen chloride are obtained by electrolysis and synthesis of refined brine ion membrane.The refined brine is subjected to ammonia absorption and carbonization to obtain heavy caustic soda and mother liquor of heavy caustic soda,and the heavy caustic soda is calcined to obtain soda ash product;The mother liquor of heavy caustic soda reacts with hydrogen chloride to obtain deamination mother liquor.The deamination mother liquor is evaporated at high temperature to obtain refined salt and salt making mother liquor.The mother liquor of salt making is evaporated at low temperature to obtain ammonium chloride products and ammonium production mother liquor.The refined salt is recycled to light brine for evaporation and concentration or becomes products.