Tibet Long Mu Wrong Saline Lake Lithium Boron Extraction Technology Was Studied

With the mine resources of lithium exhausted, the salt lake has been a main source to produce lithium in the world. In our country, the salt lake resources are rich, but the magnesium and lithium ratio is high which make the collection tough, therefore many resourses are leave unused. To achieve the comprehensive recovery of salt lake resources, this paper takes Long Mu Cuo salt lake which was in Xi Zang province as a research object, and goes on technology research about lithium ang boron in salt lake.The ion in Xi Zang Long Mu Cuo salt lake is complex, which contains lithium, magnesium, boron, calcium, sodium, potassium, bromine, chlorine and so on. The content of lithium is0.13g/L, and magnesium is12.63g/L, the magnesium and lithium ratio is about100:1. After concentrate, the content of lithium is5.4g/L, and magnesium is110.2g/L. the salt lake belongs to a chloride type which also has high magnesium and lithium ratio.This paper took the quality of salt lake into consideration, propose a’method of precipitation to collect lithium-acid way to collect boron’technology, and make a detailed study of brine. the results of the experiment proved as follows, under the conditions of the concentration of milk of lime is20percent; the temperature of water is70℃; the agitation speed is120r/min; the ratio of sodium sulfate is1:1and milk of lime, sodium sulfate and old brine together to distilled water we could remove magnesium effectively, and the removal rate as high as98.50%. under the conditions of the concentration of concentrated hydrochloric acid is36.50%; the ratio of acid and water which put into boron and magnesium precipitate is3:5; we mix and beat them slowly in a constant temperature, and then filter after5minutes, we could recover boron effectively. under the conditions of the temperature of water is60℃; we add sodium sulfate whose qualities is more than the theory5%(the rest of them) and mix50minutes; the agitation speed is120r/min, we could remove calcium effectively.and the revoval rate as high as98%. Under the conditions of the drug we used is sodium carbonate; the qualities is more than the theory300%; we add seed crystal5g/L, and mixed them slowly; the agitation speed is150r/min; the mixing time is50minutes; the temperature of water is80℃; the ageing time is720minutes. Use this technology, we could got lithium carbonate product which contains lithium14.29%, the recovery is33.53%, and got boron solution which contains boronl5.06g/L, the recovery is86%, the test index is well. The technology makes low costs of collection lithium and the synthetically use of boron and lithium come ture.Using the XRD detection to detected the crystals shape of the magnesium hydroxide sediment which in a different stirring rate in removing magnesium, the results show that, under the condition of none stir, the shape of magnesium hydroxide crystals is needle,which also thin and long, difficult to filter. under the condition of slow stir, the shape of magnesium hydroxide crystals compared wite none stir is needle, which also short and stout, difficult to filter. under the condition of quick stir, the shape of magnesium hydroxide crystals is columnar, and the particle size is small, which also easy to produce secondary nucleation, make crystal unpure.Using the SEM detection, we could observe the morphology. The results show that, the precipitation before removed boron contain a lot of calcium, magnesium, boron. the precipitation after removed boron still contain a lot of calcium, magnesium, but the content of boron is few, the state of being of boron is change, which proved the fessibility of boron extraction.