饲料级磷酸氢钙中和工艺探讨

Research on neutralization process of feed grade calcium hydrophosphate

为得到结晶颗粒较大的饲料级磷酸氢钙,采用石灰乳和碳酸钙浆料为中和剂,对饲料级磷酸氢钙的中和条件进行了一系列研究,探讨了中和条件对饲料级磷酸氢钙产品结晶的影响及对产品中磷、氟含量的影响。结果表明：采用石灰乳为中和剂时终点pH应控制在5.5-6.0,采用碳酸钙浆料为中和剂时终点pH宜控制在5.0-5.5;分别采用石灰乳和碳酸钙浆料为中和剂时,较适宜的中和温度均为40-50℃;采用石灰乳为中和剂时中和时间应为1.0-1.5 h,采用碳酸钙浆料为中和剂时中和时间应为1.5-2.0 h;采用分段中和时,前期使用碳酸钙浆料中和至pH为3.0,后期使用石灰乳中和至pH为5.5-6.0,在此条件下制得的饲料级磷酸氢钙结晶颗粒较大且较松散。

In order to get the larger crystallized feed grade calcium hydrophosphate particles,a series of researches on neutralization conditions of feed grade calcium hydrophosphate were made with lime milk and calcium carbonate slurry as the neutralizing agents.The influences of the neutralization conditions on the product′ s crystallization and on the phosphorus,fluorine contents of the product were investigated.Results showed that the end pH of neutralization should be controlled at5.5-6.0 when using lime milk as the neutralization agent,and the end pH of neutralization of calcium carbonate slurry should be controlled within 5.0 -5.5;better neutralization temperature was 40 -50 ℃ when using the two kinds of neutralizing agents respectively;the appropriate lime milk neutralization time was 1.0-1.5 h,and the better calcium slurry neutralization time was 1.5-2.0 h;during subsection neutralization experiment,using calcium carbonate slurry to neutralize pH to 3 at the early stage,and later using the lime milk neutralize pH at 5.5 -6.0.The crystal grains were bigger and more loosely under those conditions.