Study On The Morphology And Dynamics Of Boron In The Process Of Lithium Extraction In Salt Lake

The presence of boron in the late brine from the salt lake directly affects the lithium extraction process,and the existence of boron in the solution is extremely complicated and easily affected by external factors.Therefore,the study of boron has become extremely important.Since the form of metaborate in water is related to the hydration tendency of metal cations,this study selects metaborate which is easily hydrolyzed,and Mg2+and Li+which have a strong hydration tendency.The following conclusions were obtained:At 308.15K,during the isothermal forced evaporation experiment of LiBO2-H2O binary system,the solid phase precipitated was LiBO2·8H2O,and the solid phase was LiBO2·2H2O during the isothermal forced evaporation experiment of LiBO2-LiCl-H2O system.The equilibrium solid phase of the same solid solution equilibrium is the same,and the percentage in the liquid phase is also consistent with the dissolution equilibrium.In the LiBO2-H2O,Mg(BO2)2-H2O binary system,the main form of boron in LiBO2 liquid phase is B[OH)4]-,the characteristic peaks of other polyboroxy anions are not obvious,and Li+in solution The concentration has little effect on it,and the equilibrium solid phase changes;Mg(BO2)2 is hydrolyzed in water,and the form of boron in the solution changes.B4O5(OH)42-and B3O3(OH)4-are boron.The main forms accounted for 49.81%and 19.54%of the total boron content in the liquid phase,respectively.The equilibrium solid phase was Mg2B6O11·15H2O and Mg(OH)2.At 323.15K,the LiBO2-LiCl-H2O system is a simple ternary system,and the corresponding two saturated points are LiBO2-2H2O,LiBO2 and LiCl·H2O.The density reached a maximum at the saturation point of 1.3640 kg·L-1.The system has obvious solubilization during the dissolution equilibrium of 323.15K,which is consistent with other temperature phenomena.The ternary system of Mg(BO2)2-MgCl2-H2O and Mg(BO2)2-LiBO2-H2O ternary system were studied at 298.15K.The apparent concentration of Mg(BO2)2 in magnesium chloride solution was 0.79%from pure water.Increase to 1.96%when saturated with magnesium chloride.The equilibrium solid phase of Mg(BO2)2 in magnesium chloride solution is finally determined to be boehmite,Mg3Cl2(OH)4·4H2O and magnesium chloride hexahydrate;Mg(BO2)2 is hydrolyzed in lithium metaborate solution,and the equilibrium is solid.The phase is consistent with the equilibrium solid phase in water and is Mg2B6O11·15H2O and Mg(OH)2.The liquid density of Mg(BO2)2-MgCl2-H2O system reached the maximum at the saturation point,which was 1.38071 kg-L-1,and the pH decreased from 9.69 to 6.28.The liquid phase of Mg(BO2)2-LiBO2-H2O system The density reached a maximum at the saturation point of 1.05103 kg·L-1,and the pH of the liquid reached a maximum at the co-saturation point of 10.98,and the solution was alkaline.Magnesium chloride has a great influence on the hydrolysis balance of Mg(BO2)2.When magnesium chloride is saturated,B3O3(OH)4-and B5O6OH)4-are the main forms of B,which account for 44.57%and 40.00%of the total boron content of the liquid phase,respectively.B(OH)4-is the first species formed by hydrolysis of magnesium metaborate.Its concentration does not change greatly with magnesium chloride.When the concentration of magnesium chloride is 0,it accounts for 2.11%of total boron,and when magnesium chloride is saturated,it decreases to 1.83%.