运用相图理论回收缩合废水中的氯化钠和氯化铵

摘要

研究了0℃，10℃，60℃时NaCl－NH4 Cl－H2 O三元水盐体系的固液相平衡关系，测出了NaCl和NH4 Cl在水中的溶解度数据，并绘制了相图。运用该三元相图理论，采用结晶法从缩合工段母液废水中回收NaCl和NH4 Cl。讨论了回收过程原理，介绍了回收工艺的操作步骤和工艺参数。回收的NaCl纯度达到95％，总回收率大于77％，NH4 Cl纯度达到92％以上，总回收率大于40％，产品分别达到HG／T 5462—2003，GB／T 2946—2008的标准。%By means of isothermal method, solid-liquid phase equal relationship of ternary water-salt system of NaCl-NH4Cl-H2O is studied at 0 ℃, 10 ℃ and 60 ℃, the solubility data of NaCl and NH4Cl in water are obtained and phase diagram is drawn. Using the ternary phase diagrams theory, NaCl and NH4 Cl are recovered from the condensation mother waste by a crystallization method. This paper discusses the principle of the recycling process and introduces recycling tech-nological process and feature parameters. The purity of NaCl recycled can reach 95%, total recovery rate more than 77%, the purity of NH4 Cl above 92%, total recovery rate more than 40% and products can reach standard of HG/T 5462—2003 and GB/T 2946—2008 respectively.