Electrolytic production of lithium metal
The present invention provides a process for preparing lithium alloy or lithium metal from lithium carbonate or its equivalent lithium ion source such as spudomene ore without creating toxic byproducts such as halogen gases and a system adopted for such a process.
1. A process for producing lithium from lithium carbonate which comprises:
a. Providing lithium carbonate and at least an acid selected from sulfuric acid, trifluoromethane sulfonic acid, fluorosulfonic acid, triflouroboric acid, trifluoroactetic acid, trifluorosilicic acid and kinetically hindered acids in an aqueous solvent wherein lithium anion is dissolved in the solvent forming a lithium feed solution;
b. Providing an anode in contact with the solution;
c. Providing a liquid metal cathode suitable for electrolysis of lithium, wherein the liquid metal cathode is in contact with the solution forms an electrolysis cell;
d. Providing electric current to the electrolysis cell thereby producing lithium at the liquid metal cathode, forming an alloy with the liquid metal cathode;
e. isolating lithium metal from the liquid metal cathode;
wherein the isolating of lithium is conducted by an extraction process using a suitable extraction solvent.
2. The process of claim 1 , wherein the extraction solvent is selected from pentyl amine, pyridine, HMPO, isopropylamine, triethylamine, triethyltetramine, ethylenediamine or anhydrous ammonia.
3. The process of claim 2 , wherein the extraction is conducted under pressure.
4. A lithium production system utilizing electrolysis of lithium ion, which comprises
a. an electrolytic cell comprising a liquid metal cathode and an aqueous solution wherein the aqueous solution containing lithium ion and at least an anion selected from sulfate, trifluoromethane sulfonate, fluorosulfonate, triflouroborate, trifluoroactete, trifluorosilicate and kinetically hindered acid anions and wherein the lithium ion is produced from lithium carbonate;
b. a heating system maintaining the temperature of the cell and liquid metal circulating systems higher than the melting point of the liquid metal cathode but lower than the boiling point of the aqueous solution; and
c. an extraction cell wherein the reduced lithium from the electrolytic cell is extracted from the liquid metal cathode using a suitable extraction solution;
d. a distillation system for isolating the lithium metal from the extraction solution.
5. The lithium production system according to claim 4 , wherein the anion is sulfate.