A method for recovering valuable metals from waste power battery cathode waste

Abstract

The invention discloses a method for recovering valuable metals from the positive electrode waste of waste power batteries, which comprises the following steps: (1) pickling the positive electrode waste of waste power batteries to obtain a mixed solution containing nickel, cobalt, manganese and lithium; The nickel-cobalt-manganese-lithium mixed solution is removed to obtain the nickel-cobalt-manganese-lithium purification liquid and the impurity removal liquid or the impurity removal residue; (3) the nickel-cobalt-manganese is separated from the nickel-cobalt-manganese-lithium purification liquid by selective co-extraction , to obtain nickel-cobalt-manganese-containing back-extraction solution and lithium-rich raffinate; (4) carry out deep impurity removal treatment on lithium-rich raffinate to obtain lithium-rich purification solution and impurity-removal solution or impurity-removal residue; (5) lithium-rich raffinate After the purification liquid is subjected to deep oil removal treatment, it is treated by bipolar membrane electrodialysis to produce lithium hydroxide solution and sulfuric acid solution; (6) the lithium hydroxide solution is evaporated and concentrated to obtain battery-grade lithium hydroxide monohydrate products and Concentrate the mother liquor. In the method of the invention, the recovery rates of nickel, cobalt, manganese, lithium, and lithium are all greater than 98 percent, and the value-added of metal products can be realized while efficiently recovering valuable metals.

Description

technical field [0001] The invention belongs to the technical field of recovering valuable metals, and in particular relates to a method for recovering valuable metals from waste power batteries. Background technique [0002] In recent years, the rapid growth of the new energy vehicle market has brought about the rapid development of the power battery industry, but it is also facing the problem of decommissioning a large number of power batteries. Since the service life of power batteries is generally 5-8 years, this means that the new energy batteries put into the market in the early stage are basically at the critical point of elimination. Although power batteries are rich in valuable metal resources, from the perspective of chemical toxicity, the organic components and heavy metal components they contain make them have obvious hazardous waste characteristics. Therefore, whether it is from the perspective of green development or from the perspective of economy, the reuse ...

AI Technical Summary

Problems solved by technology

In the existing technology, the separation and extraction of lithium is mainly realized from the solution by means of chemical precipitation, solvent extraction and other methods. This type of method can realize the extraction and separation of lithium, but there are still low yields of valuable metals, low product quality, and The process is not environmentally friendly

For example, in patents CN101942569B, CN102676827B, CN103199320B, CN106450552A, etc., nickel-cobalt-manganese-lithium in positive electrode waste enters the leaching solution in the form of sulfate or chloride, and then separates and recovers lithium in the form of lithium fluoride and lithium carbonate respectively. This type of method can effectively separate Lithium recovery, but there are still problems such as low lithium recovery rate, poor quality of lithium salt products, high consumption of chemicals in the recovery process, and large amount of wastewater; The process technology used to prepare ternary precursors after restoration, this type of method has the advantage of short processing flow, but the obtained ternary precursor products have differences in electrochemical performance compared with commercial products, which are currently limited to laboratory research stage; there are also reports in the literature that solvent extraction is used to extract and recover lithium, and the yield of lithium can be increased to more than 85%, but there is a problem of dispersion loss of valuable metals, and the saponification of the organic phase produces a large amount of high-sodium waste water, which increases environmental protection. Handling pressure; In addition, it has also been reported that organic acids (such as citric acid, acetic acid, etc.) or alkaline systems are used to selectively leach lithium from positive electrode waste. Nickel, cobalt, and manganese are not leached directly into the slag, and subsequently recovered from the solution by chemical precipitation. Lithium, this treatment method can shorten and simplify the recovery process, but there is also the problem of low lithium yield

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