Abstract:

During the brine evaporation process，the amount of lithium loss is enormous and the lithium loss rate is usually more than 40% with the evaporation-precipitation method.In this work，the evaporation process of the high calcium brine was studied and the result showed that the reason of lithium loss was entrainment of calcium crystal salt.Therefore，the effects of scrubbing solution which was saturated calcium chloride solution，preconcentrated solution or low lithium brine were further investigated on the washing of calcium crystal salts，and the disposal of the washing liquor was also discussed.It was founded that the effect of calcium crystal salts washing was best with the preconcentrated solution mixing-centrifugal separation-spray washing method.The detailed experimental conditions were as follows：firstly，the preconcentrated solution was used to mix the slurry and spray washing calcium crystal salts.When the slurry liquid-solid ratio（mL/g） was 0.5 and the spray washing ratio（mL/g） was 0.20，the lithium concentration in the washing solution was 6.90 g/L，and the washing solution could be returned to the salt evaporation pond.Subsequently，the fresh water was used for further spray washing.When the washing ratio was 0.03，the lithium recovery rate could be increased by another 10%，the lithium concentration was about 2.66 g/L，the dissolution rate of calcium crystal salts was about 12.56%.Then，the washing solution was recommended to use it for the next stage of washing to further improve the lithium concentration，and finally return to the salt evaporation pond.As a result，the washing rate of lithium reached about 79.12% with the above-mentioned washing calcium crystal salt process，which meant that the overall lithium recovery rate could be significantly improved.

Key words: high calcium salt lake brine, calcium crystal salt, pre concentrated solution, washing, lithium recovery rate