Method for producing potassium sulphate and aluminium chloride by utilizing potassium alum

Abstract

The invention relates to a method for producing potassium sulphate and aluminium chloride by utilizing potassium alum. According to the method, the selected materials are the potassium alum, potassium chloride and water as a solvent, and the weight ratio of the potassium alum and the potassium chloride is 1.5-2.5:1. The produduction method comprises a stage for preparing the potassium sulphate through a potassium alum / potassium chloride complex decomposition reactive crystallization method, and a stage for preparing the aluminium chloride through evaporation and concentration crystallization, wherein the potassium sulphate preparation stage can be carried out for one time or several times circularly; during the stage, the replacement reaction temperature is larger than or equal to 60 DEG C, the reaction time is larger than or equal to 20min, the solid-liquid separation and insulation temperature is larger than or equal to 50 DEG C, and the evaporation and concentration crystallization temperature is larger than or equal to 90 DEG C. Compared with the existing method for producing the potassium sulphate and the aluminium chloride by utilizing the potassium alum, the method has the beneficial effects of short technological process (one-step conversion), easiness in solid-liquid separation, low energy consumption, no environment pollution, low production cost, easiness in industrialization implementation, high material utilization ratio and the like.

Description

technical field [0001] The invention belongs to the technical field of potassium sulfate and aluminum chloride production, and in particular relates to a method for producing potassium sulfate and aluminum chloride by using potassium alum. Background technique [0002] Potassium alum is a potassium aluminum sulfate double salt with the molecular formula K 2 SO 4 ·Al 2 (SO 4 ) 3 24 hours 2 O. [0003] The existing methods of utilizing potassium alum to produce potassium sulfate and aluminum chloride include alum pyrolysis method, alum ammonolysis method, alum potassium hydroxide replacement method and the like. [0004] Alum pyrolysis produces potassium sulfate and alumina. The main processes are alum dehydration (to produce dry alum, that is, anhydrous alum), thermal decomposition, desulfurization, hot water leaching, solid-liquid separation, evaporation, concentration and crystallization. There are problems, one is high energy consumption. Alum dehydration (300-400°...

AI Technical Summary

Problems solved by technology

Second, environmental pollution

Third, the process is difficult

Self-adhesive and puffing occur in the dehydration process of alum, the process is long and difficult

Fourth, the leaching solution is evaporated and concentrated to extract potassium sulfate, which has a large amount of evaporated water and high energy consumption.

There are problems, one is NH 3 Recycling and Environmental Pollution

Second, it is difficult to filter gel-like aluminum hydroxide, and high-temperature roasting consumes a lot of energy

Third, the mother liquor volume of potassium sulfate (ammonium) is large, the energy consumption of evaporation and concentration is high, and the added value of potassium and nitrogen fertilizers is low

There are problems, one is that the generated aluminum hydroxide is gel-like, and the solid-liquid separation is difficult

Second, the production cost is high

Third, the amount of potassium sulfate mother liquor is large, and the energy consumption of evaporation, concentration and crystallization is high

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