CN-120841470-B - Method for treating iron-containing waste residues by using waste to treat waste and battery-grade ferric phosphate

CN120841470BCN 120841470 BCN120841470 BCN 120841470BCN-120841470-B

Abstract

The application discloses a method for treating iron-containing waste residues by using waste to treat waste and battery-grade ferric phosphate. The method comprises the steps of S1, carrying out acid leaching treatment on iron-containing waste residues, carrying out solid-liquid separation after acid leaching to obtain first filtrate, S2, adding reducing waste residues into the first filtrate, reducing ferric iron in the first filtrate into ferrous iron, S3, adjusting and controlling the pH value of the first filtrate to be 1.5-3, carrying out solid-liquid separation to obtain second filtrate, adding phosphoric acid into the second filtrate to obtain a mixed solution, S4, adding an oxidant into the mixed solution, carrying out solid-liquid separation after reaction, and washing and drying the obtained solid to obtain ferric phosphate. The method for treating the iron-containing waste residues by using waste treatment adopts the technical idea of using waste to treat waste, at least two types of waste residues can be treated simultaneously, the treatment cost of the waste residues is reduced, the waste residues can be converted into high-value battery-grade ferric phosphate products, and the preparation cost of the battery-grade ferric phosphate is greatly reduced.

Inventors

LIU XIAOHUI
YAO YINGXIONG
TIAN XIAOXUE

Assignees

四川锦恒丰菱新材料科技有限责任公司

Dates

Publication Date: 20260508
Application Date: 20250806

Claims (9)

1. The method for treating the iron-containing waste residues by using waste is characterized by comprising the following steps: S1, carrying out acid leaching treatment on iron-containing waste residues, and carrying out solid-liquid separation after acid leaching to obtain first filtrate containing ferric iron; S2, adding reducing waste slag into the first filtrate to reduce ferric iron in the first filtrate into ferrous iron, wherein the reducing waste slag is phosphorus slag or battery black powder, and when the reducing waste slag adopts the battery black powder, firstly diluting the first filtrate with water to 6-7.5 times of the original mass to obtain a diluent; S3, adjusting and controlling the pH value of the first filtrate treated in the step S2 to be 1.5-3, and then performing solid-liquid separation to obtain a second filtrate, and adding phosphoric acid into the second filtrate to obtain a mixed solution; S4, adding an oxidant into the mixed solution, performing solid-liquid separation after the reaction, and washing and drying the obtained solid to obtain the ferric phosphate.
2. The method for treating iron-containing waste residues by using waste treatment according to claim 1, wherein in the step S2, when the reducing waste residues are ferrophosphorus residues, the adding amount of the ferrophosphorus residues is calculated by the mass of ferric iron in the first filtrate, and the mass ratio of the ferric iron to the ferrophosphorus residues is 1:1.5-3; and/or in the step S2, when the reducing waste slag adopts ferrophosphorus slag, the reaction temperature of the first filtrate and the ferrophosphorus slag is 80-100 ℃ and the reaction time is 1.5-3 h.
3. The method for treating iron-containing waste residues by using waste treatment according to claim 1, wherein in the step S2, when the reducing waste residues adopt battery black powder, the adding amount of the battery black powder is 1:30-40 in terms of the mass ratio of ferric iron in the diluent, the adding amount of sulfuric acid is 0.5-0.9:1 in terms of the mass ratio of sulfuric acid to the battery black powder, and the concentration of sulfuric acid is 98%; And/or, in the step S2, when the reducing waste residue adopts the battery black powder, the reaction temperature is normal temperature, and the reaction time is 1.5-3 hours.
4. The method for treating iron-containing waste residues by waste treatment according to claim 1, wherein in the step S3, the ratio of the molar amount of phosphate in the second filtrate to the molar amount of total iron after the phosphoric acid is added is 1.05-1.15:1 based on the total iron in the second filtrate.
5. The method for treating iron-containing waste residue by waste treatment according to claim 1, wherein in the step S3, the pH of the first filtrate is adjusted and controlled to 1.5-3 by adding an alkaline solution; Or in the step S3, the pH value of the first filtrate is adjusted and controlled to be 1.5-3, and the method comprises the steps of firstly adding battery black powder into the first filtrate, adjusting the pH value of the first filtrate to be 0.3-1.3, and then adding an alkaline solution into the first filtrate, and controlling the pH value of the first filtrate to be 1.5-3.
6. The method for treating iron-containing slag with waste according to claim 1, wherein in the step S1, the iron-containing slag includes at least one of sulfuric acid slag and copper-smelting slag; And/or in the step S1, the acid adopted in the acid leaching treatment is sulfuric acid, or the acid adopted in the acid leaching treatment is mixed acid of sulfuric acid and phosphoric acid; and/or, in the step S1, the iron-containing waste residue is subjected to acid leaching treatment for 1-3 hours at the temperature of 20-95 ℃.
7. The method for treating iron-containing waste residues by using waste as defined in claim 1, wherein in the step S1, the acid used in the acid leaching treatment of the iron-containing waste residues is sulfuric acid with the concentration of 98%, water is also added into the iron-containing waste residues in the acid leaching treatment, and the mass ratio of the iron-containing waste residues, the acid and the water is 100:80-150:200-500; Or in the step S1, when the iron-containing waste residue is subjected to acid leaching treatment, the adopted acid is mixed acid of sulfuric acid with the concentration of 98% and phosphoric acid with the concentration of 85%, and when the iron-containing waste residue is subjected to acid leaching treatment, water is also added into the iron-containing waste residue, and the mass ratio of the iron-containing waste residue to the mixed acid to the water is 100:90-300:200-500.
8. The method for treating iron-containing waste residue by waste treatment according to claim 1, wherein in the step S4, the reaction is performed for 0.5 to 1.5 hours at a temperature of 45 to 50 ℃ after the oxidant is added.
9. The battery-grade ferric phosphate is characterized in that the battery-grade ferric phosphate is prepared by adopting the method for treating iron-containing waste residues by using waste treatment according to any one of claims 1-8.

Description

Method for treating iron-containing waste residues by using waste to treat waste and battery-grade ferric phosphate Technical Field The invention relates to the technical field of industrial solid waste recycling, in particular to a method for treating iron-containing waste residues by waste treatment and battery-grade ferric phosphate. Background The lithium iron phosphate battery has been rapidly expanded in application in the fields of new energy automobiles and the like by virtue of excellent electric circulation capability, higher safety and cost advantages. As a key raw material for preparing lithium iron phosphate, the quality of iron phosphate is directly related to the physical and chemical properties of lithium iron phosphate. Battery grade iron phosphate for the production of positive electrode materials has very stringent limits on impurity content, which makes the purity requirements of the base material quite high, and high purity phosphoric acid (or phosphate) is typically used for reaction with iron salts. However, such high purity raw materials tend to be expensive, resulting in high production costs. In view of this, exploring to prepare a low-cost battery-grade iron phosphate has become a current urgent problem to be solved. In industrial production, iron-containing solid wastes such as sulfuric acid residues, copper smelting residues, iron phosphate residues, battery black powder and the like are generally processed in an independent mode due to different sources and characteristics, but the cost is high, firstly, special equipment is required to be arranged for each waste residue, the initial and operation and maintenance costs are high, secondly, the pollution treatment needs independent facilities, the investment of medicaments and equipment is large, thirdly, the unit energy consumption is high due to limited treatment capacity, and a professional team is required, the labor cost is increased, the process is complex, the efficiency is low, and fourthly, the resources are wasted due to the fact that each component is difficult to be utilized efficiently, and the implicit cost is formed. Disclosure of Invention The invention discloses a method for treating iron-containing waste residues by waste treatment and battery-grade ferric phosphate, which are used for solving the technical problems in the prior art. In order to solve the problems, the invention adopts the following technical scheme: in a first aspect, the application provides a method for treating iron-containing waste residues by waste treatment, comprising the following steps: S1, carrying out acid leaching treatment on iron-containing waste residues, and carrying out solid-liquid separation after acid leaching to obtain first filtrate containing ferric iron; s2, adding reducing waste residues into the first filtrate, and reducing ferric iron in the first filtrate into ferrous iron; S3, adjusting and controlling the pH value of the first filtrate treated in the step S2 to be 1.5-3, and then performing solid-liquid separation to obtain a second filtrate, and adding phosphoric acid into the second filtrate to obtain a mixed solution; S4, adding an oxidant into the mixed solution, performing solid-liquid separation after the reaction, and washing and drying the obtained solid to obtain the ferric phosphate. In a second aspect, the application provides a battery grade iron phosphate, which is prepared by adopting the method for treating iron-containing waste residues by waste treatment. The technical scheme adopted by the invention can achieve the following beneficial effects: the method for treating the iron-containing waste residues by using waste treatment adopts the technical idea of using waste to treat waste, at least two types of waste residues can be treated simultaneously, the treatment cost of the waste residues is reduced, the waste residues can be converted into high-value battery-grade ferric phosphate products, the preparation cost of the battery-grade ferric phosphate is greatly reduced, and the iron-containing waste residues and the reducing waste residues can be treated simultaneously by acid added during acid leaching, so that the waste treatment by using waste is realized, and the gradient utilization of acid can be realized. In particular, the following advantages are achieved: (1) The method for treating the iron-containing waste slag by using waste treatment waste adopts the iron-containing waste slag as a main treatment object, adopts the treatment idea of treating waste by using waste, uses waste slag which is originally required to be treated independently as a raw material (reducing agent) in the process, reduces the cost of waste slag from treatment, reduces the environmental risks of land occupation, heavy metal leakage, atmospheric pollution and the like caused by waste slag storage, landfill or incineration, and simultaneously, reduces the consumption of the reducing agent and the treatment cost of t