CN-122012822-A - Method for reducing and reducing zinc in dangerous waste iron slag

Abstract

The invention discloses a method for reducing and reducing zinc in dangerous waste iron slag, and belongs to the technical field of metallurgy. The method comprises the steps of adding sulfuric acid solution into dangerous scrap iron slag for size mixing and preactivation to obtain a preactivated material, adding directional complexing agent solution into the preactivated material to obtain a mixed system, reacting the mixed system under a certain condition, and carrying out solid-liquid separation after the reaction is finished to obtain reduced iron slag and complex zinc solution. The method realizes the selective removal of zinc, the stable retention of the iron-based phase and the accurate control of process parameters through the synergistic effect of weak acid preactivation and directional complexing agent, and has important metallurgical engineering significance for reducing dangerous waste properties and realizing iron slag reduction and recycling.

Inventors

• YI GUANGMING
• YANG HAIFENG
• TANG XIAOMING
• ZHANG SHANGFA
• DENG GE
• XU GANGFANG
• CAO YUANDONG
• XIANG CHENGXI
• ZHANG DECHAO
• LI KAIJIN
• HUANG HAOCHEN

Assignees

• 云南铜业股份有限公司西南铜业分公司

Dates

Publication Date

20260512

Application Date

20260318

Claims (8)

1. 1. The method for reducing and reducing zinc in the dangerous waste iron slag is characterized by comprising the following steps of: (1) Adding sulfuric acid solution into the dangerous waste iron slag to perform size mixing and pre-activation to obtain a pre-activated material; (2) Adding directional complexing agent solution into the preactivated material to obtain a mixed system, reacting the mixed system under a certain condition, and carrying out solid-liquid separation after the reaction is finished to obtain iron slag and complex zinc solution.
2. 2. The method for reducing and lowering zinc in dangerous scrap iron slag according to claim 1, wherein the concentration of the sulfuric acid solution in the step (1) is 30-50 g/L.
3. 3. The method for reducing and lowering zinc by dangerous waste iron slag according to claim 1, wherein the solid-to-liquid ratio of the dangerous waste iron slag to the sulfuric acid solution in the step (1) is 1Kg (3-6) L.
4. 4. The method for reducing and reducing zinc in dangerous scrap iron slag according to claim 1, wherein the step (1) of pre-activating the size mixing is carried out under the condition of 25-50 ℃ for 30-60 min.
5. 5. The method for reducing and lowering zinc in dangerous scrap iron slag according to claim 1, wherein the pH value of the preactivated material in the step (1) is 1.5-2.0.
6. 6. The method for reducing and lowering zinc in dangerous scrap iron slag according to claim 1, wherein the directional complexing agent in the step (2) is one or more of tartaric acid, citric acid, malic acid and sodium gluconate.
7. 7. The method for reducing and lowering zinc in dangerous scrap iron slag according to claim 1, wherein the mass ratio of the directional complexing agent in the step (2) to zinc in the pre-activated material is 10-100:1.
8. 8. The method for reducing and lowering zinc in dangerous scrap iron slag according to claim 1, wherein the reaction condition in the step (2) is that the pH value of a mixed system is regulated to 3.0-5.5, the oxidation-reduction potential of the mixed system is controlled to be 150-350 mV, and the mixed system is stirred for 60-90 min.

Description

Method for reducing and reducing zinc in dangerous waste iron slag Technical Field The invention relates to the technical field of metallurgy, in particular to a method for reducing zinc in dangerous waste iron slag. Background In the nonferrous metal pyrometallurgy process, the flue gas purification and dust removal system produces a large amount of iron-containing solid residues. The iron slag is generally rich in volatile metal elements such as zinc, lead and the like, wherein the zinc content is high, and the iron slag is mostly in the form of zinc oxide, zinc ferrite spinel and the like and is endowed in an iron-based mineral phase. Because zinc and associated heavy metals have higher leaching toxicity, the materials are often identified as dangerous wastes, and are stored and disposed according to dangerous waste specifications, so that the materials occupy storage capacity and bring higher environmental protection disposal cost and environmental risk. The existing treatment method mainly comprises high-temperature volatilization recovery, strong acid leaching, solidification landfill and the like. The high-temperature method has high energy consumption and large investment, the strong acid leaching can dissolve zinc, but the method is easy to cause a large amount of iron to be dissolved, has high acid consumption and large waste liquid amount, has poor selectivity, and has low resource utilization value because the dangerous waste property is not reduced from the source when the method is used for solidification and landfill. Therefore, it is necessary to develop a short-flow method based on selective separation and resource utilization. Disclosure of Invention In order to solve the problems of recycling and utilizing the iron-containing solid residues, the invention provides a method for reducing and reducing zinc in dangerous scrap iron residues, which specifically comprises the following steps: (1) Adding sulfuric acid solution into the dangerous waste iron slag to perform size mixing and preactivation to obtain a preactivated material. (2) Adding directional complexing agent solution into the preactivated material to obtain a mixed system, reacting the mixed system under a certain condition, and carrying out solid-liquid separation after the reaction is finished to obtain iron slag and complex zinc solution. Preferably, the concentration of the sulfuric acid solution in the step (1) is 30-50 g/L. Preferably, the solid-to-liquid ratio of the hazardous waste iron slag and the sulfuric acid solution in the step (1) is 1Kg (3-6) L. Preferably, the step (1) of the invention is performed by stirring for 30-60 min at 25-50 ℃. Preferably, the pH value of the material after the pre-activation in the step (1) is 1.5-2.0. Preferably, the directional complexing agent in the step (2) is one or more of tartaric acid, citric acid, malic acid and sodium gluconate. Preferably, in the step (2), the mass ratio of the directional complexing agent (calculated as solute) to zinc in the pre-activated material is 10-100:1. Preferably, the reaction condition in the step (2) is that the pH of the mixed system is regulated to 3.0-5.5, the oxidation-reduction potential of the mixed system is controlled to be 150-350 mV, and the mixed system is stirred for 60-90 min. Preferably, the complexing agent in the step (2) is added as an aqueous solution, the concentration of the complexing agent solution is 1-20g/L, the pH value and the oxidation-reduction potential (ORP) of the system are detected in real time through on-line monitoring equipment in the process of adding the directional complexing agent solution, and if the pH value and the oxidation-reduction potential are required to be regulated after all the directional complexing agent solution is added, the regulation can be carried out through adding the sulfuric acid solution in the step (1). The invention provides a method for reducing and reducing zinc in dangerous scrap iron slag, which has the following beneficial effects: (1) The method eliminates the defect of large amount of iron dissolution caused by traditional strong acid leaching, utilizes the difference of thermodynamic activity and complexation stability of zinc and iron by the synergistic effect of weak acid preactivation and directional complexing agent, constructs a reaction system for promoting zinc to be dissolved out preferentially, and realizes selective dezincification on the premise of not damaging the main body structure of iron base. (2) The invention effectively separates high toxic components in the iron slag through directional dezincification, remarkably reduces the quality of solid residues, realizes the substantial reduction of the iron slag, and can directly save huge dangerous waste storage and landfill cost. (3) The invention constructs a mild chemical reaction system by introducing weak acid environment and complexing agent (citric acid and the like), combines real-time online monitoring o