论文部分内容阅读
采用等温溶解度法测定了10~70℃时(NH_4)_3PO_4-NH_3·H_2O-H_2O三元系中磷酸铵的溶解度,并绘制成相应的相图.结果表明:磷酸铵的溶解度随温度降低和氨浓度升高而下降.当溶液中氨浓度相同时,温度越低,则磷酸铵的溶解度越小.采用氨溶析结晶法从磷酸铵溶液中除去钾、钠杂质时,可通过提高溶液中氨浓度以及降低温度的方式,使得磷酸铵结晶析出,钾和钠留在结晶母液中,除去钾、钠,以达到净化提纯磷酸铵的目的.
The solubility of ammonium phosphate in (NH_4) _3PO_4-NH_3 · H_2O-H_2O ternary system at 10 ~ 70 ℃ was determined by isothermal solubility method and the corresponding phase diagram was drawn.The results show that the solubility of ammonium phosphate decreases with the decrease of temperature and ammonia When the concentration of ammonia in the solution is the same, the lower the temperature, the less the solubility of ammonium phosphate.With the ammonia dissolution crystallization method to remove potassium and sodium impurities from the ammonium phosphate solution, by increasing the concentration of ammonia Concentration and temperature reduction, making the crystallization of ammonium phosphate precipitation, potassium and sodium remain in the mother liquor, remove potassium and sodium, in order to purify the purpose of purification of ammonium phosphate.