New method for producing feed additive MDCP using medium concentration wet method phosphoric acid

A process for preparing the feed additive MDCP from the middle-concentration wet phosphoric acid includes such steps as using phosphorus ore slurry and sulfuric acid to extract coarse phosphoric acid, using the defluorinating agent, impurity removing agent and flocculant to purifying phosphoric acid by constant-pressure air floating and stripping, mixing with filtered cake of calcium hydrogen phosphate, and drying. Its advantages are high utilization rate of phosphorus, low cost and short period of production. 目前，热法磷酸生产MDCP多采用热法磷酸与饲料级磷酸氢钙作原料，生产成本高。本发明中浓度湿法磷酸生产MDCP是采用磷矿浆和硫酸萃取粗磷酸，再用脱氟剂、除杂剂和絮凝剂净化粗磷酸，然后和磷酸氯钙滤饼混合制浆，再经喷雾干燥及流化床干燥制成MDCP产品，特征是用脱氟除杂净化粗磷酸，由恒压气浮脱氟除杂和气提除杂浓缩成精磷酸；具有磷利用率高，能耗低，饲肥大，对原料磷矿要求宽、中低品位磷矿都可使用的特点。中浓度精磷酸直接与饲料级磷酸氢钙在固液相中反应，反应时间短、过程易控制，具有占地小、设备少、生产周期短、成本低等优点。