【摘要】 氯磷酸钙是盐酸法磷酸生产中的中间产物,可用作磷肥和动物饲料添加剂.用3组不同原料的CaCl2和磷酸、CaHPO4.2H2O和盐酸以及盐酸法分解浏阳贫磷矿得到的粗磷酸,通过改变反应物摩尔配比等条件制得单斜晶系片状结构的CaClH2PO4.H2O.实验结果表明:以CaCl2和磷酸为原料、摩尔比为1∶1时,析出物中氯磷酸钙含量最高为92.14%;以CaHPO4.2H2O和盐酸为原料、摩尔比为1∶1.5时,其氯磷酸钙含量最大为99.06%;从含6.32%P2O5的粗酸中浓缩结晶、析出产物经乙醇洗涤后所得氯磷酸钙纯度为98.45%.比较了4种磷酸盐的IR光谱,氯磷酸钙中存在明显的氢键效应和基频相互作用,2 824 cm-1和2 209 cm-1处的吸收峰可被分别指认为和频和倍频的振动吸收.TG-DTA测定表明氯磷酸钙在第2步热分解中有结晶水和结构水的脱除,在第2个吸热峰450℃后的斜坡状失重正好与其结构水在升温速率10℃/min下的脱去吻合.更多还原

【Abstract】 Monocalcium chlorophosphate is an intermediate product in the phosphoric acid production by hydrochloric acid process,and can be used as phosphate fertilizer and animal feed additive.Using three groups of different materials: CaCl2 and phosphoric acid,CaHPO4·2H2O and hydrochloric acid,as well as the crude phosphoric acid obtained from Liuyang poor phosphate ore decomposed by hydrochloric acid method,monoclinic schistose-structural CaClH2PO4·H2O was prepared through changes of molar proportion of reactants and other conditions.The experimental results show that the highest content of monocalcium chlorophosphate in precipitates was 92.14% with CaCl2 and phosphoric acid as materials at the molar ratio of 1∶1;the maximum content of monocalcium chlorophosphate was 99.06% with CaHPO4·2H2O and hydrochloric acid as materials at the molar ratio of 1∶1.5;the purity of monocalcium chlorophosphate obtained from the crude phosphoric acid containing 6.32% P2O5 through concentration and crystallization was 98.45%,after the precipitated product was washed by ethanol.The infrared spectra of 4 kinds of phosphates are compared,and there are noticeable hydrogen bond effects and fundamental frequency interactions in monocalcium chlorophosphate,the absorption peaks at 2 824 cm-1 and 2 209 cm-1 can being assigned as the vibration absorptions of sum frequency and double frequency,respectively.TG-DTA determinations indicate that monocalcium chlorophosphate in the thermal decomposition of the second step has the removal of crystal water and structural water,and the sloping weight loss after the second endothermic peak 450 ℃ just coincides with the elimination of its structural water at a heating rate 10 ℃/min.更多还原