英文摘要 |
This study focuses on the negative and positive components of scrap lithium-iron battery for material analysis and recycling of lithium, aluminum, iron, and copper. According to results of component analysis, that the waste lithium-iron battery positive electrode and the negative electrode material are both comprised of the major inorganic substances. The full metal contents were determined as 29,566 mg/kg, 131,555mg/kg and 254,667mg/kg, lithium, aluminum and iron respectively. The negative electrode comprised of 409,999 mg/kg copper metal. After leaching studies of the positive electrode material, the optimum leaching conditions were determined as: 1N sulfuric acid at a solid-liquid ratio 3g / 50ml, for 0.75 hr at 27 ℃. Under these conditions, the lithium, iron and aluminum recovery rates were 100%, 100% and 2.57% respectively. When the leaching solution pH was adjusted to a pH value of 7.00, the precipitation of iron and aluminum recoveries were up 100%, while about 77% of the lithium metal was obtained after filtration. This filtration residue was purified by crystallization at 70 ℃ for 5hr to obtain lithium sulfate crystallization products with a purity of 94.8%.
In order to recover 23% of the lithium metal remained in the lithium (Li), aluminum (Al), iron (Fe) precipitate, this precipitate was leached for 1 hour in 1N sulfuric acid leaching solution at a 3g/50ml solid/liquid ratio at 27℃. After leaching, the iron-based product remaining contained 3% Li, 2.57% Al, and 100% Fe. The leachate was subjected to pH adjustment with ammonia water, followed by crystallization. Successfully, 20% of the lithium metal was recovered.
The optimum leaching conditions for the negative electrode material were as follows: 10 times the theoretical amount of H2O2 added to 1N sulfuric acid, liquid ratio 1g/50mL, 70℃ and 0.5hr. Under these conditions, leaching copper metal recovery was up to 100%. This copper leaching solution was under went electrolysis at a current density of 50 (A/m2) and room temperature for 3hr. A 100% electrolytic copper recovery rate was achieved. Alternative, this copper leaching solution can be crystallized for 5hr at 70℃ to obtain copper sulfate crystallization products with a purity of 80%.
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