Method for intensively removing chlorine in zinc-containing steel dust mud by utilizing electric field

Abstract

The invention discloses a method for intensively removing chlorine in zinc-containing steel dust sludge by using an electric field. The method comprises the following steps: fully reacting the zinc-containing steel dust sludge with water according to a certain solid-to-liquid ratio, reaction temperature, reaction time, stirring speed and current density conditions, carrying out solid-liquid separation after the reaction is finished, and recycling the obtained leaching residues through a pyrogenic process / wet process. Compared with the prior art, the method has the advantages that the chlorine in the zinc-containing steel dust mud can be efficiently removed, and the chlorine and other metal resources in the zinc-containing steel dust mud can be separated and recycled. The method has the advantages of energy consumption reduction, simplicity and convenience in operation and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste resource utilization and chlorine removal, and specifically relates to a method for removing chlorine from zinc-containing steel dust by utilizing electric field enhancement. Background Art

[0002] Iron and steel metallurgical dust is solid waste generated in the production process of the steel industry. Zinc-containing iron and steel dust is a type of hazardous solid waste with a high recycling value. It mainly comes from the dust removal system of blast furnaces, oxygen converters, electric arc furnaces and other related processes, and contains a variety of valuable metals such as iron, carbon, zinc, potassium, and sodium. The amount of zinc-containing dust produced in steel plants is generally about 10% of steel production.

[0003] At present, only a small amount of dust is returned to sintering for internal circulation in steel enterprises. Most of the dust contains a chlorine mass fraction of up to 28% to 30%. Directly returning zinc-containing steel dust to the steel production process will cause the chlorine element to circulate and enrich in it, resulting in an unstable sintering process, affecting the strength and other metallurgical properties of the sintered ore, and causing the blast furnace to be unable to operate normally. In addition, the enrichment of chlorine elements will also seriously corrode smelting equipment. These zinc-containing dusts that cannot be recycled normally accumulate in the factory, which will damage the surrounding ecological environment and pollute groundwater and soil. Therefore, in order to ensure that the zinc-containing steel dust can operate stably in the enterprise in the later stage, the zinc-containing steel dust must be pre-treated for dechlorination before entering the blast furnace.

[0004] However, the leaching rate of chlorine in zinc-containing steel dust and mud by traditional water washing is only about 80%; acid washing can make the chlorine removal rate in zinc-containing steel dust and mud reach more than 90%, but zinc and other metals in zinc-containing steel dust and mud will also be leached intensified, among which the leaching rates of zinc and iron are as high as 50% and more than 10% respectively. This method is not conducive to the separation and recovery of chlorine and other metals in the leachate. Therefore, it is urgent to find a method with low energy consumption and high efficiency that can not only strengthen the chlorine removal in zinc-containing steel dust and mud but also reduce the leaching of valuable metals such as zinc.

[0005] The present invention is based on the principle of electric field enhanced leaching. After introducing an electric field into the leaching system, the leaching of chlorine in zinc-containing steel dust can be enhanced, while reducing the leaching of metal elements such as zinc in the zinc-containing steel dust. The method has the advantages of low leaching temperature, low energy consumption, simple operation, and easy equipment availability. At the same time, it can realize the separation and recovery of chlorine and other metal resources in zinc-containing steel dust. Summary of the invention

[0006] The purpose of the present invention is to provide a method for removing chlorine from zinc-containing steel dust by electric field enhancement. By controlling the leaching time, leaching temperature, liquid-to-solid ratio and current density, the leaching of zinc and other metal elements can be suppressed while ensuring efficient leaching of chlorine. The method can achieve separation and recovery of chlorine and other metal resources in zinc-containing steel dust. The specific steps are as follows:

[0007] (1) Add zinc-containing steel dust to a reaction tank, set the solid-liquid ratio of zinc-containing steel dust to water to 1:2 to 1:8, add cathode and anode plates to the reaction tank, and introduce a direct current electric field.

[0008] (2) At a set reaction temperature of 25-80°C and a current density of 0-80 mA / cm 2 Stir thoroughly for 10 to 60 minutes under the conditions, with a stirring speed of 50 to 80 r / min.

[0009] (3) After the reaction is completed, the zinc-containing steel dust sludge leaching system in (2) is subjected to solid-liquid separation.

[0010] Compared with the prior art, the present invention has the following benefits:

[0011] Compared with the prior art, the leaching rate of chlorine in the method of the present invention is higher than 90%, and the leaching rate of valuable metal ions such as zinc is lower than 10%. The method can strengthen the separation of chlorine and other metal resources in zinc-containing steel dust mud, and the filtrate after leaching is recycled by evaporation and concentration, and the filter residue is recovered by pyrolysis / wet method to recover the valuable metal resources, thereby realizing the comprehensive resource utilization of zinc-containing steel dust mud; in addition, the implementation process of the present invention is simple, the operation is simple, the equipment is easy to obtain, and the cost is low. DETAILED DESCRIPTION

[0012] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0013] Example 1

[0014] Weigh 5 kg of zinc-containing steel dust and place it in a reaction tank, add 30 L of water, and set the current density to 1.50 mA / cm 2 The electric field was set, and both the cathode and cathode plates were DSA plates. The water bath temperature was adjusted to 25°C, and the mixture was stirred at a stirring speed of 80 r / min for 30 min to make it uniform, thereby obtaining a mixed system A. Then, the mixed system A was subjected to solid-liquid separation, and the pH of the leaching solution was 5.8. The leaching rates of Cl and Zn were calculated to be 92.06% and 9.88%, respectively, and the Fe concentration in the leaching solution was lower than the detection limit.

[0015] Example 2

[0016] Weigh 5 kg of zinc-containing steel dust and place it in a reaction tank, add 30 L of water, and set the current density to 10.00 mA / cm 2The electric field was set, and both the cathode and cathode plates were DSA plates. The water bath temperature was adjusted to 30°C, and the mixture was stirred at a stirring speed of 80 r / min for 20 min to make it uniform, thereby obtaining a mixed system A. Then, the mixed system A was subjected to solid-liquid separation, and the pH of the leaching solution was 5.7. The leaching rates of Cl and Zn were calculated to be 90.12% and 9.54%, respectively, and the Fe concentration in the leaching solution was lower than the detection limit.

[0017] Example 3

[0018] Weigh 5 kg of zinc-containing steel dust and place it in a reaction tank, add 30 L of water, and set the current density to 15.00 mA / cm 2 The electric field was set, and both the cathode and cathode plates were DSA plates. The water bath temperature was adjusted to 80°C, and the mixture was stirred at a stirring speed of 80 r / min for 15 min to make it uniform, thereby obtaining a mixed system A. Then, the mixed system A was subjected to solid-liquid separation, and the pH of the leaching solution was 5.8. The leaching rates of Cl and Zn were calculated to be 93.85% and 9.87%, respectively, and the Fe concentration in the leaching solution was lower than the detection limit.

[0019] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for removing chlorine from zinc-containing steel dust by electric field enhancement, characterized in that: The steps include: First, zinc-containing steel dust is added to the reaction tank to control a certain liquid-solid ratio; second, under the set reaction temperature conditions, anode and cathode plates are added to the reaction tank, a DC electric field is introduced, and the reaction is fully stirred; finally, after the reaction is completed, a plate and frame filter press is used to separate the solid and liquid.

2. The method for removing chlorine from zinc-containing steel dust and sludge by electric field enhancement as claimed in claim 1, characterized in that: The solid-liquid ratio of zinc-containing steel dust to water in the reaction tank is 1:2 to 1:8, and the stirring speed is set to 50 to 80 r / min.

3. The method for removing chlorine from zinc-containing steel dust and sludge by electric field enhancement as claimed in claim 1, characterized in that: The set reaction temperature is 25-80°C.

4. The method for removing chlorine from zinc-containing steel dust and sludge by electric field enhancement as claimed in claim 1, characterized in that: The cathode and anode plates of the electrolytic cell are DSA electrode plates or electrode nets plated with ruthenium, iridium, titanium or lead.

5. The method for removing chlorine from zinc-containing steel dust and sludge by electric field enhancement as claimed in claim 1, characterized in that: The current density is set to 0~80mA / cm 2 , the reaction time is 10 to 60 minutes.