Synthesis of Lithium Fluoride from Spent Lithium Ion Batteries

Abstract

Lithium (Li) is considered a strategic element whose use has significantly expanded. Its current high demand is due to its use in lithium ion batteries for portable electronic devices, whose manufacture and market are extensively growing every day. These days there is a great concern about the final disposal of these batteries. Therefore, the possibility of developing new methodologies to recycle their components is of great importance, both commercially and environmentally. This paper presents results regarding important operational variables for the dissolution of the lithium and cobalt mixed-oxide (LiCoO 2 ) cathodes from spent lithium ion batteries (LIBs) with hydrofluoric acid. The recovery and synthesis of Co and Li compounds were also investigated. The dissolution parameters studied were: temperature, reaction time, solid-liquid ratio, stirring speed, and concentration of HF. The investigated recovery parameters included: pH, temperature, and time with and without stirring. The final precipitation of lithium fluoride was also examined. The results indicate that an increase in the HF concentration, temperature, and reaction time favors the leaching reaction of the LiCoO 2 . Dissolutions were close to 60%, at 75 • C and 120 min with a HF concentration of 25% (v/v). The recovery of Co and Li were 98% and 80%, respectively, with purities higher than 94%. Co and Li compounds, such as Co 3 O 4 and LiF, were synthesized. Furthermore, it was possible to almost completely eliminate the F − ions as CaF 2 .

Extraction of Titanium from Low-Grade Ore with Different Leaching Agents in Autoclave

“…The optimal extraction of titanium, 89%, was achieved at 80 min for the lixiviant H 2 SO 4 -HF medium (10% v/v and 15% v/v, respectively). These results are expected since fluid-solid reactive reactions are generally slow [13][14][15][16]. Similar results to ours were obtained by Das et al, Agatzini et al, Begum et al, Habashi, Nguyen and Lee and Haverkamp et al [1][2][3][4][5][6], who conducted operating parameter studies on sands, mud and minerals with sulfuric and hydrochloric media, finding in all cases that the increase in reaction time increases the dissolution of these materials.…”

“…These results are as expected for a solid-liquid solution reaction since the magnitude of the dissolution of the metals present in the solid depends on the temperature (the general rule is that the increase of the temperature also increases the extent of the dissolution). In addition, it should be taken into account that the increase in temperature also increases the reactivity of solids [13][14][15][16]. Thus, 123 • C was selected to continue the study of the other operating parameters.…”

“…This hinders the interaction between the leaching agent and the sample, thus decreasing the leaching reaction. The results of Figure 8 indicate that the increase in the stirring speed slightly affects the titanium dissolution, which would allow us to say that the transfer of mass (or leaching agent) through the boundary layer (Nernst layer) is maximal [13][14][15][16].…”

“…Figure 9 shows the XRD of the waste from different leaching conditions. boundary layer (Nernst layer) is maximal [13][14][15][16].…”

Progress and Status of Hydrometallurgical and Direct Recycling of Li-Ion Batteries and Beyond

“…Another inorganic acid tested in academic research is hydrofluoric acid (HF). According to Suarez et al, cobalt leaching efficiencies reached 98% with HF but did not achieve full leaching of lithium (80%) [184]. Considering the safety and environmental hazards related to HF and the poor performances obtained, this leaching agent is of low interest.…”