The Isolation And Purification Of Manganese Sulfate Crude

A large amount of manganic wastewater is directly discharged, which will badly pollute the environment, when Chuanqing Chemical Plant produces hydroquinone. This paper is to research the producton of manganese sulfate based on the recycle of this kind of wastewater in order to make efficient use of resources, however, because of high content of ammonium root in the wastewater, the product obtained from the above process is only crude manganese sulfate with relatively high content of ammonium sulfate the content of MnSO4 ? H2O in the rude is about 87%, and that of ammonium sulfate is about 11%, unfortunately, there is no effective methods to isolate and purify this kind of crude manganese sulfate at home and abroad so far.According to the property of major components in the crude (manganese sulfate and ammonium sulfate), isolation and purification are carried out under laboratory condition by using recrystallization, precipitation and direct heating method. Recrystallization method can not achieve the purpose of isolation, and precipitation method is able to get a good result of isolation but the cost is too high.Direct heating method is to put the crude into an open system and semi-closed system, and heate the crude until white smoke can't be observed, then put into boiling furnace Ma again in order to further decompose the undecomposed ammonium sulfate with a constant temperature. Research shows that the cotent of manganese(Mn2 +) in the prodct manganese sulfate gained is over 35% no matter how it's put in the open system or semi-closed system when the controlled temperature of Ma boiling furnace is 520°C. The content of major impurities in the product is measured referring to HG/T 2962-1999 standards, and the results are that iron content≤0.0032%, chloride content≤0.005% and water-insoluble content≤0.0015%, which reaches the requirement of HG/T 2962-1999.The content of anhydrous manganese sulfate which is converted from the product manganese sulfate isolated by direct heating method is stably more than 97%, and the experimental apparatus and steps are both relatively simple, and besides, the process of isolation has no pollution to environment, therefore, this method has higher reference value to extend the application of experiment.