Technical Process And Engineering Design Of Preparation Of Strontium Hydroxide By Celestite

The paper systematically investigated the technical process and engineering design of preparation of strontium hydroxide by celestite, mainly including the process of the carbothermic reduction of celestite, the water leaching of SrS, the crystallization of strontium hydroxide octahydrate, the desulphurization of the waste liquor, and the design of reaction equipment, which could produce70g strontium hydroxide octahydrate per unit yield.The carbothermic reduction of celestite was studied by using thermodynamic analysis method. Thermodynamic calculations of the process of carbothermic reduction of celestite were carried out, and the process conditions of carbothermic reduction of celestite were optimized. It was found that the optium roasting temperature was1100℃, the optium roasting time was2h, the optium mass ratio of celestite ore and metallurgical coke was8:1, and the optium particle size was75μ m～96μm. The convertion rate of strontium sulfate could be95%on the optium conditions.The process of water leaching of SrS was researched by using thermodynamic calculations. With optimizing the process conditions of water leaching of SrS, it showed that the optimized rotation rate was300r/min, the optimized leaching temperature was100℃, the optimized time was4h, the optimized liquid to solid ratio was80:1, and optimized particle size was75μ m～96μ m. On the optium conditions, the extraction rate of strontium sulfide was93.85%. In this investigation, the shrinking core model was used to describe the process of water leaching of SrS. Laboratory results indicated that when the mixing speed exceeded300r/min, the effect of liquid film diffusion to the process was greatly reduced. This lecture also revealed that the process of water leaching of SrS was controlled by solid membrane diffusion and interface migration, and its apparent dynamics equation could be expressed as1/3ln(1-X)+[1-(1-X)-1/3-1]=5064.45exp[45.08/(RT)]t, in which the apparent activation energy and pre-exponential factors were45.08KJ/mol and5064.45.The process of crystallization of strontium hydroxide octahydrate was investigated with the method of thermodynamic analysis. In addtion, the crystals were qualitatively analysed by using X-ray diffusion and were viewed by adopting scanning electron microscope. The reseach about process conditions of crystallization of strontium hydroxide octahydrate manifested optium conditions. And on the optimized conditions, the crystallization contained high content of strontium hydroxide,99.56%, and uniform distribution of grain size. In this thesis, the technological process and equipments of preparation of Strontium hydroxide in a laboratory scale were detailed designed, including a batch stirred reactor, and a batch crystallizer et al.