Abstract
	The world lithium consumption is permanently growing in last 10 years and it is possible to forecast its gradual growth. The main area of lithium consumption is in production of lightweight alloys and  primary or  secondary lithium batteries. Another significant use of lithium is in lithium compounds, namely Li2CO3. Lithium carbonate is the starting material for the industrial production of all other lithium compounds and is itself used in the ceramic and glass industry in large quantities. In the present time most lithium and lithium compounds are produced from lithium bearing silicate ores containing about 1.6-3.6 % Li or from lithium-bearing brines containing 0.06-0.15% Li. Promising alternative sources of lithium are spent lithium batteries or lithium-containing alkaline wastewaters, which are formed during the production of so-called liquid rubber and which were processed in this study. These wastewaters contain between 3-6 g Li/l,  0,4-0,6 g methylalcohol/l, are insignificantly  contaminated with Na, Si, Fe, Zn, Al, K and organic compounds,  the concentration of which does not exceed  60 mg/l.  Lithium, which is present in these solutions  as lithium hydroxide was precipitated as Li2CO3 using CO2. This method is based on the different solubility of LiOH and Li2CO3 in water and the fact that the solubility of Li2CO3 is very low compared with that of alkali metal carbonates present in the wastewaters processed. Approximately  90% lithium precipitation efficiency and entire removing of organic compounds were achieved if the processed wastewaters were condensed up to lithium concentration of 10-12 g/l. Precipitation of Li2CO3 was conducted at two steps. During the first step LiHCO3 is formed under the CO2 excess at 40oC, at the second step more soluble LiHCO3 is transformed to sparingly soluble Li2CO3 at 95oC, whilst most impurities remain in the solution. Obtained carbonate precipitates contain from 98.6 to 99.7% Li2CO3 depending on the purity of processed wastewater and lithium concentration in the original solution.   Such Li2CO3 are  suitable intermediates for the production of lithium compounds or metallic lithium. Grain size of    Li2CO3 prepared depends on the impurity concentration in the processed wastewater. Increasing impurity concentration resulted in growing of Li2CO3 grain size.