| Resource of Lithium is very rich in China. Most of brines from salt-lake or underground, with a high content of Lithium, have great potential to develop. But in some brines, the content of Magnesium is very large, relative high ratio of Mg/Li hampers the advance of Lithium industry.The object in this study is intercrystalline brine from a salt-lake in Qinghai (Mg/Li=60~70). Taking into account of comprehensive utilization and reducing cost, a practical and economical lithium-extracting technological method has been found, which is fit for industrial production.This method is mainly made up of two steps: the first step is natural evaporating and concentrating brine; the second step is precipitating and separating Magnesium and Lithium .In the process of evaporation, under the direction of phase diagram method, the main purpose is how to separate kinds of salt by-product, enrich Lithium, decrease the ratio of Mg/Li. The study shows that the Lithium can be concentrated to about 0.8%, the ratio of Mg/Li can be lowed to 10; In the process of precipitating, in order to separate the left Magnesium and Lithium, a lot of experiments were carried out with the Sodium carbonate or Calcium hydroxide and Sodium Sulfate anhydrate as precipitator of Magnesium, where the separation results were compared, and an optimal separation idea was proposed.In this experimental research, some optimal technical conditions and operation parameters were decided, which can be applied to those brines with high ratio of Mg/Li. Based on the principle of the method, high-quality product of Lithium carbonate can also be got. Furthermore, this conclusion helps to provide designing and controlling basis for further industrial researches or experiments about extracting Lithium.
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