公开(公告)号：EP2471739A1

公开(公告)日：2012-07-04

申请号：EP11150103.7

申请日：2011-01-04

申请人： SOLVAY SA

发明人： Verdoes, Dirk ,  van der Meer, Johannes ,  Nienoord, Michiel ,  Collard, Jean-Marie ,  Sell, Michael

IPC分类号： C01B25/234 ,  B01D9/00

CPC分类号： C01B25/234 ,  B01D9/0045

摘要： Process for purifying a stream comprising phosphoric acid and a first amount of impurities, wherein
■ A slurry of phosphoric acid crystals in a water mother liquor is formed;
■ The phosphoric acid crystals are separated from the mother liquor by filtration in a wash column comprising at least one filtering element (4), while a packed bed of crystals coming from the slurry forms near said filtering element (4);
■ The separated phosphoric acid crystals are washed in the wash column by bringing a washing liquid in countercurrent to the crystals in the bed up to a wash front, where the washing liquid recrystallizes, the bed being subjected to a movement in the direction of said wash front (6b);
■ A purified stream comprising phosphoric acid and a reduced amount of impurities is formed by melting at least part of the washed crystals;
■ The purified stream is extracted from the wash column through a product outlet of the wash column;

characterized in that water is introduced into said wash column (1), between the wash front (6b) and the product outlet and/or in a melting circuit (8,10,11,21) producing at least part of the washing liquid, and wherein the introduction of the said water decreases the equilibrium temperature of the contents of the melting circuit (8,10,11,21).

摘要翻译： 纯化包含磷酸和第一量杂质的物流的方法，其中 - 形成在母液中的磷酸晶体的浆料; - 在包括至少一个过滤元件（4）的洗涤塔中通过过滤将磷酸晶体与母液分离，而来自浆料的晶体的填充床形成在所述过滤元件（4）附近; - 将分离的磷酸晶体在洗涤塔中洗涤，将洗涤液与床中的晶体逆流至清洗前，洗涤液重结晶，床沿洗涤方向移动 前面（6b）; - 通过熔化至少部分洗涤的晶体形成包含磷酸和减少量杂质的纯化物流; - 纯化的物流通过洗涤塔的产物出口从洗涤塔提取; 其特征在于，在所述洗涤塔（1）中，在所述洗涤前部（6b）和所述产品出口之间和/或在产生至少部分所述洗涤液体的熔解回路（8,10,11,21）中引入水， 并且其中所述水的引入降低了熔解回路（8,10,11,21）的内容物的平衡温度。