The Process Research Of Making The Potassium Sulphate By The Method Of Ammonium Sulfate—The Simulation Of The Potassium Sulphate Purification And The Evaporating Crystallization Of Low Energy Consumption Mother Liquor

As a kind of excellent potash fertilizers,potassium sulphate is widely used in agricultural production.The process of producing potassium sulphate by ammonium sulphate is one of the mainstream technologies for the production of potassium sulphate in China.The technology has many advantages,such as easy availability of raw materials,stable process and environmental protection,etc.,but the product quality and utilization of potassium are still to be improved.In this subject,the ammonium sulfate process of Shanghai Research Institute of Chemical Industry is taken as basis to carry out the process research on the improvements of product quality by purification experiment and the recovery of potassium resources by evaporation and crystallization of mother liquor.In addition,the research has application value.The factors affecting product quality and conversion rate,such as potassium chloride dosage,water yield ratio,reaction temperature and reaction time,etc.,were investigated in this paper.On this basis,the uniform design method was used to optimize the purification process parameters,and regression analysis and variance analysis were used to obtain the optimal reaction conditions:50%of potassium chloride dosage,0.8 of water yield ratio,25 ?of the reaction temperature,20 minutes of the reaction time.Meanwhile,an expanded validation experiment at the kilogram level was also carried out in the research,in which the conversion rate reached 85.48%and K,O content of the refined potassium sulfate reached 51.07%.The product meets the requirements of top quality product with national standard.The potassium sulfate evaporation system was simulated with Aspen software and two evaporation crystallization processes of three-effect down stream evaporation crystallization and two-effect counter current evaporation crystallization were researched.Moreover,the intermittent evaporation crystallization experimental device was set up to experimentally determine the process parameters of various-effect evaporation crystallization nodes,and the experimental data were fed back to optimize the calculation process of evaporation crystallization.The results show that there is little difference in operability between the two processes,but the energy consumption of two-effect counter current is 42.6%higher than that of three-effect down stream.Furthermore,the conceptual design of potassium sulphate production scale with 20,000 tons/year was performed in this paper.The material and energy balance calculation was carried out for the key refining reaction section in the process,the process and material balance diagram design and key device selection calculation were completed and the project economic evaluation was completed by using professional software.