Method for producing battery-grade ferric orthophosphate from titanium dioxide solid waste

Abstract

The invention belongs to the field of new energy battery materials, and comprises a method for producing battery-grade ferric orthophosphate from titanium dioxide solid waste. The method comprises thefollowing effective steps: adding water for thoroughly dissolving the titanium dioxide solid waste, adding a flocculant, and then performing multi-stage sedimentation filtration to obtain a high-purity ferrous sulfate solution; thoroughly mixing the prepared ferrous sulfate solution and a phosphorus source solution according to a molar ratio of 1:1 in a reaction kettle, then controlling the pH ofthe solution to be 5-7, controlling the temperature at 25-35 DEG C, reacting for about 2 hours while stirring to obtain a ferrous phosphate slurry and sodium sulfate; filtering and washing the ferrous phosphate slurry and the sodium sulfate after a reaction to remove sodium sulfate, slurrying a filter cake after washing, and dispersing and sanding the ferrous phosphate slurry; mixing the sanded ferrous phosphate slurry and phosphoric acid according to a molar ratio of 1:1 to 1:2 in the reaction kettle, adding an oxidizing agent, thoroughly reacting, heating the slurry to 80-100 DEG C, and aging for 2-3 hours; cooling a ferric phosphate slurry after the reaction, washing and performing tympanic membrane suction filtration, then conveying and drying to remove free water, and then removing crystal water through calcination to obtain the battery-grade ferric orthophosphate.

Description

technical field [0001] The invention belongs to the field of new energy battery materials, and in particular relates to a method for producing battery-grade iron orthophosphate from titanium dioxide solid waste. Background technique [0002] Titanium dioxide is a high-grade and high-quality white inorganic pigment. At present, the production methods of titanium dioxide include sulfuric acid method and chlorination method. The production of titanium dioxide by sulfuric acid method produces about 3.5-4 tons of ferrous sulfate per ton of titanium dioxide. . As a result, a large amount of waste paraferrous sulfate is produced. If such a large amount of waste paraferrous sulfate is still used in the original accumulation method, the large site occupied and the impact on the environment will seriously restrict the development of the titanium dioxide industry. [0003] In order to fully recycle the waste ferrous sulfate, in the past, some people used titanium dioxide waste ferrous...

AI Technical Summary

Problems solved by technology

As a result, a large amount of waste paraferrous sulfate has been produced. If such a large amount of waste paraferrous sulfate is still used in the original accumulation method, the large site occupied and the impact on the environment have seriously restricted the development of the titanium dioxide industry.

[0003] In order to fully recycle the waste ferrous sulfate, in the past, some people used titanium dioxide waste ferrous sulfate as iron catalyst, water purifier, feed additive, soil improver, etc. The relative output of titanium dioxide waste In terms of the amount of ferrous sulfate, the consumption of these treatment approaches is very small, and there is still a large amount of waste secondary ferrous sulfate that needs to be comprehensively utilized, otherwise serious environmental pollution will be caused, and valuable resources will be wasted

[0004] With the large-scale use of lithium iron phosphate batteries, iron phosphate is used as the main raw material for lithium iron phosphate cathode materials, and its demand has greatly increased. However, the current preparation of iron phosphate generally adopts the process of reacting ferrous salts, oxidants and phosphates. But there are problems: 1. Since ferric ions are particularly easy to hydrolyze and precipitate, so in the process of preparing iron phosphate, impurities such as ferric hydroxide are easily produced, resulting in low purity of iron phosphate; 2. The purification of iron solution, especially in which Manganese, magnesium, nickel, sodium and other ions are difficult to remove at a lower cost, so high-purity iron raw materials must be used, such as high-purity iron powder and high-purity ferrous sulfate, resulting in high costs; 3. Liquid phase precipitation There are problems such as too coarse particle size to prepare ferric phosphate, but the superfine ferric phosphate prepared by sol and other methods has disadvantages such as impurity is not easy to wash off; 1 micron; 5. The amount of waste water is large, generally one ton of iron phosphate waste water is produced up to 100 tons

[0005] In order to solve the above-mentioned technical problems, according to relevant chemical reactions, people try to use the waste ferrous sulfate of titanium dioxide as the raw material for the preparation of ferric phosphate, and obtain gratifying results. There is a certain amount of solid waste and high energy consumption. Therefore, there is an urgent need for an energy-saving and environmentally friendly method that can reduce or eliminate solid waste and low energy consumption to produce ferric orthophosphate from titanium dioxide waste ferrous sulfate.

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