Metal extraction from slag of Incineration plant

Metal extraction from slag of Incineration plant

Incineration plant is a way of treating urban garbage, which converts garbage into ash and slag through high-temperature combustion. The slag contains a certain amount of metal elements, such as copper, aluminum, zinc, etc., which can be extracted and reused to achieve resource conservation and environmental protection. This paper will introduce the operation steps and technology of metal extraction from the slag of Incineration plant.

1、 Principles of Metal Extraction from Furnace Slag

The metal elements in the slag mainly exist in the form of oxides, which can be converted into metals through reduction reactions. Commonly used reducing agents include coke, charcoal, silicon powder, etc. Among them, coke is the most commonly used reducing agent. The Chemical equation of the reduction reaction is as follows:

Metal oxide+reducing agent Metal+oxide

For example: CuO+C Cu+CO

2、 Operating steps for extracting slag metal

1. Sample preparation of slag

Slag samples were obtained from Incineration plants and ground into powder. Place the powder sample in a test tube for future use.

2. Preparation of reducing agent

Grind the coke into powder and screen to obtain coke powder with appropriate particle size.

3. Slag metal extraction experiment

Mix the slag sample and coke powder in a certain proportion and place them in the furnace tube for reduction reaction. The reaction temperature is generally 800 ℃ -1200 ℃, and the reaction time can be adjusted according to experimental needs. After the reaction, the product is removed and dissolved in acid to obtain a metal ion solution.

4. Precipitation and separation of metal ions

The metal ions in the metal ion solution are precipitated, usually with sodium hydroxide or ammonium hydroxide. After sedimentation, centrifuge and wash thoroughly with deionized water.

5. Detection of metal elements

Use atomic absorption spectrometry or Inductively coupled plasma emission spectrometry and other instruments to detect and analyze metal elements.

3、 Technology for extracting metal from slag

1. Coke reduction method

The coke reduction method is the most commonly used slag metal extraction technology, with the advantages of low cost and easy operation. However, its disadvantage is that the reaction temperature is high, the equipment requirements are high, and it is easy to cause environmental pollution.

2. Aluminum oxide electrolysis method

Aluminum oxide electrolysis method is a new type of slag metal extraction technology, which has the advantages of low reaction temperature, low equipment requirements, and the ability to simultaneously extract multiple metal elements. However, its disadvantage is that it has a high cost and requires a large amount of electrical energy support.

3. Solvent extraction method

The solvent extraction method is a chemical extraction technique with the advantages of high extraction efficiency, the ability to simultaneously extract multiple metal elements, and low environmental pollution. However, its disadvantage is that it has a high cost and requires a large amount of organic solvents.

4、 Summary

Slag metal extraction is a technology of Recycling and environmental protection. Its principle is to extract metal elements from slag through reduction reaction. The commonly used slag metal extraction techniques include coke reduction, alumina electrolysis, and solvent extraction. In practical operation, it is necessary to select appropriate techniques and operating steps based on experimental needs, and detect and analyze the extracted metal elements.

Metal extraction from slag of Incineration plant