Method for measuring iron content of lithium iron phosphorous oxide iron source raw material of lithium ion power battery anode material

Abstract

The invention relates to a method for measuring the iron content of a lithium iron phosphorous oxide iron source raw material of a lithium ion power battery anode material. The method comprises the following steps: placing an iron salt raw material into a muffle furnace for high-temperature calcinations; heating and dissolving a calcined product by using concentrated hydrochloric acid; adding a proper amount of deionized water to adjust the acidity of a solution; continuously heating the solution till boiling; adding a few drops of methyl hesperidin indicators; adding a high-concentration stannous chloride solution until the solution becomes straw yellow; slowly and dropwise adding a low-concentration stannous chloride solution until the solution becomes pink; and shaking uniformly to obtain a colorless transparent solution; quickly cooling; adding a proper amount of sulfur-phosphorus mixture acid; dropwise adding a few drops of sodium diphenylaminesulfonate indicators; and titrating a potassium dichromate standard solution, and completing a reaction process when the solution is changed from blue-green into purple. The method is convenient to operate and easy to control in the whole process and accurate in the test result. Compared with the conventional method, the method has the advantages that mercury salt is not adopted, so the health of operation staff is not damaged, the environment pollution is avoided, and the method is suitable for testing of the lithium iron phosphorous oxide iron source raw material of the lithium ion power battery anode material.

Description

technical field [0001] The invention relates to the field of lithium-ion battery cathode materials, in particular to a method for determining iron content in lithium-iron-phosphorus-iron source raw materials for lithium-ion power battery cathode materials. Background technique [0002] Lithium-ion batteries are widely used in notebook computers, digital cameras, electronic instruments, mobile phones and other fields because of their advantages such as high voltage, high energy density, good cycle performance, small self-discharge, no memory effect, and wide working range; in recent years , Lithium-ion batteries are widely used in the fields of large-capacity energy storage equipment such as electric bicycles, electric vehicles, and aerospace. Among them, lithium iron phosphorus oxide material is the preferred cathode material for these large-capacity batteries because of its many advantages that other cathode materials do not have. [0003] Since 1997 J. B. The Goodenough...

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Problems solved by technology

[0004] At present, there are many chemical analysis methods for testing the iron content of iron sources, the most commonly used of which is the classic SnCl 2 -HgCl 2 Preredox Potassium Dichromate (K 2 Cr 2 o 7 ) method to determine iron content, although the accuracy of this method is relatively high, but mercury salts cause great pollution to the environment and are very harmful to human health

In order to overcome the shortcoming of pollution, a mercury-free method for iron determination appeared subsequently, such as TiCl 3 method, methyl orange method, etc., but the test accuracy is not good

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