Analysis of a Process for Producing Battery Grade Lithium Hydroxide by Membrane Electrodialysis

Abstract

A membrane electrodialysis process was tested for obtaining battery grade lithium hydroxide from lithium brines. Currently, in the conventional procedure, a brine with Li+ 4–6 wt% is fed to a process to form lithium carbonate and further used to produce lithium hydroxide. The disadvantages of this process are its high cost due to several stage requirement and the usage of lime, causing waste generation. The main objective of this work is to demonstrate the feasibility of obtaining battery grade lithium hydroxide monohydrate, avoiding production of lithium carbonate. A laboratory cell was constructed to study electrochemical kinetics and determine energetic parameters. The effects of current density, electrode material, electrolyte concentration, temperature and cationic membrane (Nafion 115 and Nafion 117) on cell performance were determined. Tests showed that a current density of 1200 A/m2 and temperatures between 75–85 °C allow reduced specific electricity consumption (SEC) (7.25 kWh/kg LiOH). A high purity product is obtained at temperatures below 75 °C, with a Nafion 117 membrane and low electrolyte concentration. Resulting key electrochemical data would enable a pilot-scale process implementation to obtain lithium compounds.

Application and Analysis of Bipolar Membrane Electrodialysis for LiOH Production at High Electrolyte Concentrations: Current Scope and Challenges

“…On the other hand, LiOH production by membrane electrolysis has reported an SEC of 6.1–14.6 kWh∙kg −1 LiOH using initial LiOH solutions between 4 and 8 wt% as the initial catholyte [ 66 ] and 7.25 kWh∙kg −1 of LiOH for an initial catholyte of 2.3 wt% [ 29 ].…”

“…The Atacama Desert in Chile is characterized by high levels of solar radiation-between 6.7 and 10.55 kWh•m −2 per day [74,75]. The application of membrane technologies for LiOH production-such as membrane electrodialysis [29] and bipolar electrodialysis membranes-is a potential alternative to the LiCl to Li 2 CO 3 and subsequent Li 2 CO 3 to LiOH conversion steps. Obtaining Li 2 CO 3 from lithium brine reports an approximate SEC of 1.31 kWh•kg −1 of Li 2 CO 3 [67], which implies an equivalent SEC of 6.83 kWh•kg −1 of LiOH (considering obtaining 0.38 kg of LiOH per kg of Li 2 CO 3 for a 59% reaction conversion [68]).…”

“…Among them, the work of Melnikov et al [ 28 ] stands out, where from a LiCl solution with organic solvents, the authors produced LiOH by bipolar membrane electrodialysis, reaching a LiOH concentration of 0.3 M with a specific energy consumption of 6.6 kWh∙kg −1 and a current efficiency of 0.6. Grageda et al [ 29 ] analyzed a membrane electrodialysis process to produce high-purity lithium hydroxide, determining the effects of concentration, current density, and temperature on process energy performance and product purity; the authors reported a specific energy consumption of 7.25 kWh∙kg −1 of LiOH. On the other hand, Ryabtsev et al [ 30 ] used membrane electrolysis to obtain lithium hydroxide from lithium carbonate treated with sulfuric acid, taking advantage of the high solubility of Li 2 SO 4 , and managing to obtain a high average LiOH concentration of 45 g∙L −1 , similar to that obtained in the conventional LiOH process.…”

One-Step Solvometallurgical Process for Purification of Lithium Chloride to Battery Grade

“…After the selective dissolution/precipitation step, the ethanol solvent can be recovered by distillation and reused in the process, and the remaining solid LiCl can be further processed to obtain battery-grade LiOH•H 2 O. For this, an aqueous LiCl solution can be transformed first into a LiOH solution, for instance by membrane electrodialysis, followed by crystallization of LiOH•H 2 O [14,26]. A demonstration of this conversion of LiCl into LiOH•H 2 O was outside the scope of the present study.…”

Life Cycle Assessment and Techno-Economic Assessment of Lithium Recovery from Geothermal Brine

“…This process involves several stages and generates wastes. One alternative pathway is to produce LiOH directly from a LiCl solution via electrolysis, 32 which is similar to the membrane cell chlor-alkali process that produces NaOH from NaCl. Chlorine gas and hydrogen gas are produced from anode and cathode, respectively, as co-products.…”