Process for preparing lithium salts such as anhydrous lithium hydroxide and anhydrous lithium halides
The present invention relates to a method for producing lithium salts, such as lithium hydroxide and lithium halides, wherein the lithium salts obtained are substantially free of water and optionally other impurities, such as lithium carbonate and/or lithium oxide. Moreover, the present invention refers to lithium salts, such as lithium hydroxide and lithium halides obtainable by said method, as well as their use for the production of e.g. solid electrolytes, lithium metal or lithium carbonate.
1 . A method for producing a lithium salt which is substantially free of water comprising the steps of:
(i) providing lithium hydroxide as a starting material in a reactor, wherein the starting material is in solid form, and
(ii) subjecting the starting material of step (i) to a stream of carrier gas at room temperature or elevated temperatures in a range of 20-80° C.
(iii) contacting the product obtained after step (ii) with a halogen-containing gas, thereby forming lithium halides, wherein step (iii) is carried out at room temperature or elevated temperatures in a range of 20-300° C., and wherein the halogen-containing gas is selected from the group consisting of HCl, HBr, HF, HI, and mixtures thereof.
2 . The method according to claim 1 , wherein the starting material in step (i) is LiOH, LiOH·H 2 O or a mixture thereof.
3 . The method according to claim 1 , wherein the carrier gas is an inert gas, including argon, dry air and/or nitrogen.
4 . The method according to claim 1 , wherein the carrier gas is introduced into the reactor at a rate of 0.1-1000 m 3 /h and/or exits the reactor at a rate of 0.1-1000 m 3 /h.
5 . The method according to claim 1 , wherein the product obtained after step (ii) is substantially free of Li 2 CO 3 and/or Li 2 O.
6 . The method according to claim 1 , wherein the halogen-containing gas is introduced into the reactor at a rate of 40-5000 g/h.
7 . The method according to claim 1 , wherein step (iii) comprises applying a stream of gas comprising the halogen-containing gas in a volume concentration of 0.001-100 vol. %, based on the total volume of the gas stream.
8 . The method according to claim 1 , wherein step (iii) comprises applying a stream of gas comprising a carrier gas.
9 . The method according to claim 1 , wherein the carrier gas is introduced into the reactor at a rate of 0.1-1000 m 3 /h and/or exits the reactor at a rate of 0.1-1000 m 3 /h.
10 . The method according to claim 1 , wherein the carrier gas and/or the starting material and/or the halogen containing gas acts as a fluid in a fluidized bed reactor.