Utilization of natural brines to produce lithium fluorides and lithium-containing fluorides for the purpose of applying them in electrolytic aluminum production

摘要

For the first time, lithium-containing brines of calcium-chloride type. being widespread in the south of the Siberian platform, are proposed to use for producing cheap fluorides enriched by lithium fluoride. Their application will allow us to have an effective additive to the electrolyte during aluminum electrolysis. The process developed to produce lithium-containing fluorides comprises selective extraction of lithium out of the brines using granulated sorbent on the basis of LiCl centre dot 2Al(OH)_3 centre dot mH_2O and fluorination of obtained eluates enriched by lithium chloride. During fluorination of eluates of selective lithium sorption after their concentration, which contain as little as 40 g/l Lid and impurities of magnesium and calcium chlorides, a mixture of fluorides (LiP, MgF_2, CaF_2) with LiF contained no less than 55 percent was produced Magnesium and calcium impurities removal from the eluates allows us to obtain lithium fluorides of high purity degree (to 90 percent) Alkaline eluates (for example, LiCl and NaOH mixture) can be used for utilization of fluorine from waste electrolysis gases, reducing detrimental HF emissions into the atmosphere.