Preparation Of Battery Grade Superfine Iron Phosphate In Imping Scream

The iron phosphate is widely used as a battery electrode material and as a precursor of lithium iron phosphate to produce the anode.The iron-lithium battery is also the battery industry with the highest market share and the largest battery consumption in the booming new energy automotive industry.Because of its low price,abundant raw materials and stable performance,it has always been favored in the energy storage industry.With the continuous increase of battery output,the continuous improvement of the industry,and the continuous improvement of environmental protection in China,industrial waste recycling battery cathode has also become a huge industry,and in the future the main source of battery materials is battery recycling.In this dissertation,according to the current research hotspots of battery cathode materials,the research on the preparation of battery-grade ultra-fine iron phosphate by hydrothermal method using impact flow reactor was carried out.On the basis of this,the p-reparation process of the battery grade ultrafine iron phosphate from the battery anode industrial waste was carried out and the effect of reaction conditions on the particle size was investigated.And explored the effect of reaction conditions on product particle size.Firstly,FeSO₄ was used as the source of iron,H₃PO₄ as the source of phosphorus,H₂O₂ as the oxidant,adding sulfuric acid,and the iron phosphate was prepared by hydrothermal method.The indexes were analyzed and characterized,and compared with the industry standard HG/T 4701-2014,the experimental products met the requirements of the battery grade ultrafine iron phosphate.Secondly,the effect of oxidation time,dosage of oxidant,reaction,crystallization time,reaction temperature,concentration of reactants and molar ratio,type and amount of dispersant,amount of wash water on product impurity residue and product particle size was carried out,and the appropriate process conditions were obtained;The battery positive electrode industrial waste was recovered to prepare battery-grade ultrafine iron phosphate,and the process was improved to obtain suitable process conditions.The experimental results show that the type of dispersant has no significant effect on the particle size of the product,and the increase in the amount of dispersant can significantly reduce the particle size of the product.Increase of reaction,crystallization time,reaction temperature favor the reduction of particle size.Too large or too small reactant concentration and molar ratio are not conducive to the reduction of product particle size.The oxidation time,the amount of oxidant,and the amount of water used for washing increase the purity of the product.Experiments show that the appropriate conditions using FeSO₄ as the iron source,H₃PO₄ as the phosphorus source,and H₂O₂ as the oxidant to prepare the battery grade ultrafine iron phosphate were as follows:During the preparation of the raw material liquid,the oxidation reaction temperature was 65?,the excess amount of hydrogen peroxide was 120%of the theoretical amount,and the oxidation time is 1 hour;in the impinging flow reactor,the reaction,crystallization temperature was 90°C,and the Fe³⁺concentration was 0.4 mol/L,phosphorus and iron ratio of 1.4:1,reaction,crystallization time of 4 hours,select PEG as a dispersant,the amount of theoretical iron phosphate production of 2%,the end point of the pH value of 2.0,washing water consumption was 6 times of the filter cake.The experimental results show that the appropriate conditions for preparing battery-grade ultrafine iron phosphate from industrial wastes were as follows:During the preparation of the raw material liquid,for every 150 g of industrial waste,the amount of hydrogen peroxide added was 25.6 mL,the amount of sulfuric acid used was 89.9 g,the oxidation reaction temperature was 65?,the amount of hydrogen peroxide was 120%of the theoretical amount and the oxidation time was 1 hour;The adjustment tank was charged with 7.56 g of iron powder,24.54 mL of hydrogen peroxide,and 23.52g of phosphoric acid.In the impinging stream reactor,crystallization temperature of 90?,Fe³⁺concentration of 0.4mol/L,and ratio of phosphorus to iron of 1.4:1.The crystallization time was 2 hours.PEG was selected as the dispersant.The dosage was 2%of the theoretical iron phosphate production.The end point of the pH value of2.0,The final filter cake was washed with 5%acetic acid solution of 6times of the filter cake.