Study on dissolution crystallization for extraction of potassium and separation of magnesium and lithium from salt lake brine
In order to solve the process difficulties of extracting potassium from salt lakes in Qinghai and extracting lithium from high magnesium lithium ratio salt lake brine,the dissolution crystallization method was used to extract potassium from salt lakes and reduce the magnesium lithium ratio.The effects of different types of solvents,such as addition amount,dissolu-tion temperature,and dissolution time,on the yield of potassium chloride and the magnesium lithium ratio in salt lakes were investigated using organic solvents as dissolution agents.The results showed that when anhydrous ethanol was used as the dissolution agent,with volume ratio of 2∶1 to salt lake brine,dissolution temperature of-15℃,and dissolution time of 90 min,the yields of potassium chloride and sodium chloride reached 93.15％and 99.84％.The mother liquor was filtered at 70～80 ℃ and cooled dynamically at cooling rate of 0.5 ℃/min to precipitate magnesium chloride crystals.The mass ratio of magnesium to lithium was decreased from 388.44 to 266.63.Finally,the rapid separation of potassium chloride was real-ized and it provided more favorable conditions for the further separation of magnesium and lithium.
dissolution crystallizationpotassium chloridehigh magnesium lithium ratiosalt lake brineseparation of mag-nesium and lithium
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