Method for recovering nuclear matrix protein (NMP) solvent in production of lithium ion battery

Abstract

The invention relates to a method for recovering a nuclear matrix protein (NMP) solvent in production of a lithium ion battery. The method comprises the following processing steps: (1) absorbing an NMP mixed gas by using a spray absorption tower, preparing an NMP mixed solution with high concentration, pumping and conveying the NMP mixed gas to the spray tower, and conveying NMP crude product liquid to a crude product tank; (2) rectifying and heating the NMP crude product liquid in vacuum to separate water from the NMP, wherein the recovered product is led to a mixing compartment to put into production via a pipeline, so that the NMP is used and recycled over and over again in a reciprocating manner. The water and the NMP are orderly separated in a gaseous form in a heating manner, and purified by in condensing and collecting manners, so as to achieve the target of recovering the product.

Description

technical field [0001] The invention designs a method for secondary recovery and recycling of lithium battery auxiliary raw materials, in particular a method for recovery of NMP solvent in the production of lithium ion batteries. Background technique: [0002] Today, as the production process of square aluminum shell lithium batteries is becoming more and more mature, the market prospect of aluminum shell lithium batteries is very broad, followed by the shrinking of product profit margins, so while pursuing quantity and product quality, we must start from the cost of raw materials. Although the price of the NMP solvent used in the positive electrode ingredients is not high among the raw materials of lithium batteries, it is used in a large amount. NMP, or N-methylpyrrolidine, is a liquid that is condensed with γ-butyrolactone as a raw material and methylamine. It is highly volatile, highly permeable, easy to absorb water and can be miscible with water in any proportion. NM...

AI Technical Summary

Problems solved by technology

NMP as a pulping medium is separated from the pole piece after the coating is completed. The traditional recovery method is to collect the gaseous air containing high-temperature NMP after being condensed and liquefied by cooling water through a gas-liquid heat exchanger, but the recovery rate of this method is relatively low. Low, insufficient cooling, some NMP gaseous emissions will cause certain pollution to the environment, and the power consumption is relatively large

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