A novel approach for ultrasonic assisted organic acid leaching of waste lithium-containing aluminum electrolyte and recovery of lithium

Abstract

In the production of Chinese aluminum industry, the accumulation and storage of many waste aluminum electrolytes containing lithium causes severe environmental pollution and is also a waste of lithium resources. Therefore, extracting lithium from waste aluminum electrolytes can supplement the market's demand for lithium resources and achieve the regeneration and utilization of solid waste resources. This article proposes a method for ultrasonic-assisted organic acid leaching of lithium-containing waste aluminum electrolytes and lithium recovery. It was found that organic acid malonic acid could selectively leach lithium from waste lithium containing aluminum electrolyte. Under the conditions of ultrasound power of 400 W, the malonic acid concentration of 2 mol/L, the liquid-solid ratio of 25:1, leaching temperature of 80 °C, and a leaching time of 2 h, the leaching rate of Li reaches 92.37%, which is 4% higher than conventional leaching. Ultrasound is used to optimize the leaching conditions and save production costs. Neutralize the leaching solution to obtain the Na3AlF6 by-product, which can be returned to the aluminum electrolysis cell for further use. Finally, high-purity lithium carbonate products were obtained through precipitation, forming a new technology for clean and efficient lithium recovery from waste aluminum electrolytes.