Research On The Reaction Equilibrium Of Potassium Leaching Process And The Crystallization Kinetics

Chloride type brine of potassium fertilizer production in Saline Lake, usually adopt flotation, eutectic liquid potash solution for producing potassium chloride and sodium chloride, containing large amounts of potassium chloride, the usual practice put light brine ore pool, or by mixing brine recovery of potassium chloride, these two methods have the problem of low recovery rate. Dilution can obtain high recovery rate using bischofite. The solventing out process includes leaching desalting and dissolved in two parts of carnallite, the two dilution process of reaction rate and the crystallization process is the key factor affecting the design and engineering process control. Therefore, the potash solution as raw material and using bischofite condensate agent, in addition to the topic of reaction kinetics and the crystallization kinetics of salt and dissolving carnallite.The phase diagram of NaCl-MgCl2-KCl three system as the basis, the sodium chloride, potassium chloride, carnallite three salt eutectic point as the desalting target brine; sodium chloride, magnesium chloride, carnallite three salt eutectic liquid as dissolving carnallite mother liquid. The reaction kinetics were investigated. In addition, the reaction kinetics of potassium salt, crystallization kinetics and carnallite dissolving process, so as to determine the reaction time and conversion rate (salt removal rate, the relationship between potassium release rate); determine the crystal size changes and control method. The results are as follows:(1) the solventing out except the reaction kinetics of salt, potassium salt dissolved in water to the available potassium chloride, sodium chloride, carnallite three-phase eutectic point analysis method (E) solution, the theory of salt removal rate was48%, the dynamic equation of solventing out desalting process.(2) the reaction kinetics of E dissolving carnallite brine, brine to E by adding dissolving agent bischofite, making carnallite precipitated, theory of potassium ion precipitation rate is80%.(3) the solution of carnallite dynamics consists of crystallization and crystallization process of feeding two. The two processes are studied respectively from the particle size and settling velocity distribution, results show that the leaching process of feeding speed is slower, the higher the crystallization; crystallization process in feeding feeding frequency is higher, the higher the crystal size.(4) on the crystallization kinetics of continuous crystallization, the crystallization of bottom material adding dissolving agent and potassium saturated solution as a cycle of operation, the crystal size distribution, settling velocity distribution of. The results showed that the more the number of cycles, the higher the crystal size. Therefore, this study to ascertain the reaction kinetics and the crystallization kinetics of leaching desalting, solvent crystallization process, the crystallization behavior of continuous crystallization, the crystallization process development, process design, process control has an important guiding significance for carnallite dissolved.