针对真空制盐-盐硝联产五效蒸发工艺中芒硝所含水不溶物的含量过多、导致卤水浊度超标影响芒硝质量的问题，研究分析水不溶物产生的源头，找出控制水不溶物生成的方法具有重要意义。采用X射线衍射（XRD）、电子扫描显微镜（SEM-EDS）和红外光谱分析（FT-IR）等分析手段对芒硝中水不溶物的物相组成和形貌特性进行分析，确定芒硝水不溶物主要成分为方解石型碳酸钙。发现水不溶物形成的主要原因是盐系统中的钙离子浓度过高，此时溶液过饱和度高、处于不稳定状态，碳酸钙析出较快，结晶数目较多、颗粒小。小颗粒的碳酸钙漂浮在循环母液中通过转卤进入硝系统，与硝系统本身产生的碳酸钙相加导致芒硝中水不溶物的含量超标。针对此问题提出了源头调控的方案。在净化过程中当碳酸钠的质量浓度由1.32 g/L调整为1.35~1.38 g/L时，可以控制卤水中钙离子与碳酸根的平衡，降低盐、硝系统中的钙离子浓度，进而达到控制水不溶物的含量。在新一轮工业化生产中，采用源头调控的方法对芒硝中水不溶物进行了有效控制，芒硝质量得到了明显提升。

In view of the excessive content of water insoluble matter in the five?effect evaporation process of vacuum NaCl-Na₂SO₄ co?production，which leads to excessive brine turbidity and affects the quality of sodium sulfate，it is of great significance to study and analyze the source of water insoluble substance and find out the method to control the water insoluble substance.X-ray diffraction（XRD），scanning electron microscopy（SEM-EDS） and infrared spectroscopy（FT-IR） modern analysis techniques were used to analyze the phase composition and morphology characteristics of water insolubles in sodium sulfate.It was determined that the main component of water insoluble in sodium sulfate was calcite calcium carbonate.It was found that the formation of water insoluble matter was mainly due to the high calcium ion concentration in the salt system.At this time，the solution was in an unstable state with high supersaturation，rapid precipitation of calcium carbonate，large number of crystals and small particles.The small particle calcium carbonate floated in the circulating brine and entered the sodium sulfate system through brine transfer，which was added with the calcium carbonate produced by the sodium sulfate system itself，resulting in the content of insoluble matter in sodium sulfate exceeding the standard.Aiming at this problem，the scheme of source regulation was put forward.In the purification process，when the addition amount of sodium carbonate was adjusted from 1.32 g/L to 1.35~1.38 g/L，the balance between calcium and carbonate in brine could be controlled，and the calcium ion concentration in salt and sodium sulfate system could be reduced，so as to control the excessive content of water insoluble substances.In the new round of industrial production，using the method of source control，the water insoluble matter in sodium sulfate had been effectively controlled，and the quality of sodium sulfate had been significantly improved.