盐酸法制备低氟含量饲料级磷酸氢钙的工艺研究

Technology for Preparing Feed-Grade Dicalcium Phosphate with Low Content of Fluorine via Hydrochloric Acid Route

在不添加任何除氟剂的条件下,用盐酸浸取磷矿,通过调整工艺参数和采用特殊的试验条件,制备了低氟含量饲料级磷酸氢钙;着重探讨了盐酸浓度、反应时间、静置时间、温度、鼓气速率等因素对磷酸氢钙中氟含量的影响.结果表明,在盐酸溶解过程中减少氟的溶出,有利于在反应中同步降低氟含量;得到的磷酸经简单的过滤、中和,可用于制备氟含量低达0.1%(低于国家标准0.18%)的饲料级磷酸氢钙.

Through adjusting process parameters and adopting special experimental conditions,feed-grade dicalcium phosphate with low content of fluorine was prepared via leaching phosphate ore with hydrochloric acid in the absence of any defluorinating agents.The effects of concentration of HCl,reaction time,retention time,temperature and foaming on the content of fluorine in dicalcium phosphate were investigated.Results indicate that inhibiting dissolution of F during leaching of phosphate ore in HCl contributes to simultaneously decrease F content in title product.Phosphoric acid obtained along with leaching in HCl,after simple filtration and neutralization,can be well used to prepare feed-grade dicalcium phosphate with low F content of 0.1% （lower than corresponding national standard 0.18%）.