湿法磷酸装置污水处理探讨

Research on Sewage Treatment for Phosphoric Acid Plant with Wet P rocess

针对磷复肥装置为实现污水全封闭、零排放 ,并满足副产的磷石膏再浆洗涤后能符合做建筑材料原料的质量要求 ,指出K+ 、Na+ 在污水封闭循环利用中不断积累 ,是造成磷酸装置过滤和浓缩系统的设备与管道结垢严重、清洗周期大大缩短、开工率低、产量远远低于设计能力的主要因素。分析了增设污水处理站的必要性 ,常规的污水处理流程不能消除K+ 、Na+ 的积累 ,通过试验证实 ,再浆洗涤后磷石膏的滤洗液经中和后 ,采用戈尔过滤膜进行固液分离 ,所得的清净水循环利用 ,可使生产正常 ,并就80kt/a(P2 O5计 )磷酸装置按上述两污水处理流程建污水处理站进行了技术经济分析 ,认为采用戈尔膜过滤器的污水处理流程优越性显著 。

Regarding the achievement of completely closed se wage and zero discharge in the phosphate compound fertilizer plant and meeting t he quality requirement that the by-product phosphogypsum can be used as raw mat erial for building material after repulping and rewashing, it is pointed out tha t the continuous accumulation of K + and Na + in the closed and circulated use of sewage is the main factor which causes severe scaling of equipment and pipes in the filtering and concentration system of phosphoric acid plant, as well as significantly shortened cleaning period, low start-up rate and production capac ity far under design capacity. It analyzes the necessity to add the sewage treat ment station. The accumulated K + and Na + can not be eliminated through norma l sewage treatment process, and it is experimentally verified that normal produc tion can be achieved by reusing the clean water obtained with gel filtering memb rane from the solid-liquid separation of neutralized filtered liquid from phosp hogypsum after repulping. The technical and economic analysis is also made for b uilding sewage treatment stations regarding the above two sewage treatment proce sses for the 80 kt/a (as P 2O 5) phosphoric acid plant and it is considered th at the sewage treatment process using gel membrane filter is advantageous and ha s better economic benefit.