Method for recycling and removing aluminum from waste lithium iron phosphate battery

Abstract

The invention relates to a method for recycling and removing aluminum from waste lithium iron phosphate batteries. The method comprises the following steps: sequentially carrying out aluminum removal reaction, solid-liquid separation, i-time washing and leaching treatment on positive electrode material powder of the waste lithium iron phosphate batteries, wherein j + 1th washing liquid obtained after j + 1th washing in the previous batch is adopted for j-th washing, and pure water is adopted for i-th washing; wherein 2 < = i < = 6, 1 < = jlt; i, and i and j are integers. According to the method, aluminum removal through dilute acid replaces aluminum removal through an alkaline method in the prior art, and the method is simple, efficient, safe, environmentally friendly and convenient for industrial application; meanwhile, the aluminum removal effect is good, and lithium loss and iron loss are small; aluminum removal is completed before leaching, so that the influence of aluminum on the subsequent process can be greatly reduced, and the recovery efficiency of the waste lithium iron phosphate battery is improved; and circulating countercurrent washing is adopted, so that the use efficiency of water is increased to the greatest extent, the use amount of water is reduced, and the production cost is reduced.

Description

technical field [0001] The invention relates to the field of recycling lithium iron phosphate batteries, in particular to a method for recycling and removing aluminum from waste lithium iron phosphate batteries. Background technique [0002] At present, lithium iron phosphate cathode materials have been widely used, such as in electric buses, electric bicycles, electric buses, large-scale energy storage and other fields. Mainly because the lithium iron phosphate cathode material has a theoretical specific capacity of 170mAh / g, which can reach 3.5V for the lithium charging platform; and compared with traditional lithium battery materials, lithium iron phosphate has a wide range of raw material sources, outstanding safety performance, and cost. Low temperature, good thermal stability, good cycle performance, green environmental protection, is an ideal power cathode material. At the same time, in recent years, as the state's subsidy for new energy vehicles has been decreasing,...

AI Technical Summary

Problems solved by technology

Although organic immersion is simple and easy to do, the required organic solution is expensive and difficult to control. At the same time, the environmental pollution is serious and the damage to the human body is relatively large.

Alkali leaching can remove most of the aluminum, but it also takes away most of the iron, and the iron needs to be replenished later. At the same time, the removal of aluminum is not thorough enough, and it is difficult to meet the industry standard for the aluminum content of commercially available battery-grade iron phosphate.

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