Method for reduction dezincification of zinc-containing dust
By compounding tar residue, biomass, bentonite and water with zinc-containing dust materials into pellets, and using microwave heating for reduction, the problems of complicated zinc-containing dust treatment steps and high energy consumption in the existing technology are solved, and the problem is achieved. Efficient dezincification and energy saving and emission reduction.
Patent Information
- Application Number
- CN202411441685.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-01-21
AI Technical Summary
The prior art has problems such as cumbersome steps, high energy consumption, high cost and low dezincification rate when dealing with zinc-containing dust. Most of the reduction processes rely on coal as a reducing agent, which increases the consumption of fossil energy and carbon emissions.
Tar residue, biomass, bentonite and water are mixed with zinc-containing dust materials to form zinc-containing dust pellets, which are reduced by microwave heating to achieve dezincification.
It significantly improves the dezincification rate, is simple to operate, has low energy consumption and low cost, reduces the consumption of fossil energy and carbon emissions, and achieves waste treatment and energy conservation and emission reduction.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of iron and steel metallurgy, and more particularly to a method for reducing and dezincifying zinc-containing dust. Background Art
[0002] A large amount of dust and sludge is generated during the steel production process, such as zinc dust, which is rich in various valuable elements such as Fe, Pb, Zn, C, and some rare elements such as In, Ag, Sn, etc., and its content is even higher than that of some primary mineral resources. Since zinc dust contains a large number of useful elements, it needs to be recycled. If it is discarded at will, it will not only pollute the environment, but also waste resources.
[0003] At present, there are two main methods for treating zinc-containing dust: wet process and pyrometallurgical process. Among them, the wet process mainly utilizes the property that zinc oxide can be dissolved in acid and alkali, and uses acid or alkali leaching solutions to separate and collect zinc, but the wet process has problems such as low recovery rate and easy corrosion of equipment. The rotary kiln reduction process and rotary hearth furnace reduction process are more commonly used in the pyrometallurgical process. They utilize the difference in boiling points of metal elements in the dust, so that metal oxides are reduced by reducing agents at high temperatures, and low-boiling point metals volatilize at high temperatures. Zinc has a low boiling point (907°C), and zinc oxide can be reduced to zinc vapor under high temperature conditions and discharged with flue gas, entering the collection system for condensation and recovery. Other high-boiling point elements remain in the slag and can be further processed and separated for recovery.
[0004] However, the current pyrometallurgical process has problems such as complicated steps, high energy consumption, high cost and low dezincification rate. In addition, most reduction processes use coal as a reducing agent, which increases fossil energy consumption and carbon emissions.
[0005] Therefore, how to develop a zinc-containing dust reduction and dezincification method that saves energy and reduces emissions is an urgent problem that technicians in this field need to solve. Summary of the invention
[0006] In view of this, the object of the present invention is to provide a method for reducing and dezincifying zinc-containing dust to solve the deficiencies in the prior art.
[0007] In order to achieve the above object, the present invention adopts the following technical solution:
[0008] A method for reducing and dezincifying zinc-containing dust, specifically comprising the following steps:
[0009] (1) adding tar residue, biomass, bentonite and water to the zinc-containing dust material, mixing evenly, pelletizing, and drying to obtain zinc-containing dust pellets;
[0010] (2) The zinc-containing dust pellets are reduced by microwave heating and then cooled in an oxygen-free environment to obtain reduced zinc-depleted pellets.
[0011] Furthermore, in the above step (1), the zinc dust material is at least one of blast furnace dust, electric furnace dust and steelmaking converter dust.
[0012] Furthermore, in the above step (1), the amount of tar residue used is 20%-40% of the mass of the zinc-containing dust material.
[0013] The further beneficial effect of adopting the above method is that tar residue is a solid waste generated in the coking production process, and its generation mainly comes from a series of physical and chemical reactions that occur during the heating process of coal. As the temperature gradually increases, the moisture, volatile matter and organic matter such as aromatic hydrocarbons in the coal gradually escape and form gas phase products, and the remaining part of the liquid forms a viscous black liquid after cooling, namely tar residue. The main components of tar residue include coke powder, coal dust, coal tar pitch, etc., which contain a certain amount of fixed carbon, volatile matter, ash and sulfur and other elements.
[0014] The present invention creatively prepares zinc-containing dust pellets from tar residue and zinc-containing dust materials. The liquid phase components and viscosity of the tar residue can provide bonding effect and better dispersibility during pelletizing, thereby ensuring the strength of the zinc-containing dust pellets, realizing the coordinated treatment of tar residue and zinc-containing dust materials, and achieving waste treatment with waste.
[0015] Furthermore, in the above step (1), the biomass is at least one of straw, coconut shell and bagasse.
[0016] Furthermore, in the above step (1), the amount of biomass used is 20%-40% of the mass of the zinc dust-containing material.
[0017] A further beneficial effect of adopting the above method is that biomass mainly refers to wood cellulose (referred to as lignin) such as straw and trees other than grain and fruit in the agricultural and forestry production process, waste materials from agricultural and forestry processing industry, and livestock manure and waste in the animal husbandry production process.
[0018] The present invention utilizes the low sulfur content and carbon neutrality of biomass, effectively reducing the emission of sulfur oxides and carbon in the reduction process, which is in line with the future trend of green and low-carbon development of the steel industry. The carbon in biomass can be used in combination with the self-carbon in zinc-containing dust materials to meet the carbon consumption of reducing zinc-containing dust. Moreover, my country is rich in biomass resources. Using biomass resources as a reducing agent can reduce the use of fossil fuels while avoiding the waste of biomass resources and reducing costs.
[0019] Furthermore, in the above step (1), the amount of bentonite used is 1%-3% of the mass of the zinc-containing dust material.
[0020] A further beneficial effect of the above method is that after the bentonite is bonded to the zinc-containing dust material, not only will no chemical change occur, but its bonding properties will not change at high temperatures, which enables the bentonite to effectively improve the balling performance of the zinc-containing dust material and enhance the strength and thermal stability of the zinc-containing dust pellets.
[0021] Furthermore, in the above step (1), the amount of water used is 5%-10% of the mass of the zinc dust-containing material.
[0022] Furthermore, in the above step (1), the pelletizing equipment is a disc pelletizing machine, the pelletizing time is 10-20 minutes, and the particle size is 8-10 mm.
[0023] Furthermore, in the above step (1), the drying equipment is an oven, the temperature is 120-180° C., and the time is 20-30 min.
[0024] Furthermore, in the above step (2), the microwave heating equipment is a microwave reduction furnace, the temperature is 1000-1200° C., and the time is 1-2 h.
[0025] The further beneficial effect of the above method is that the present invention directly heats the zinc-containing dust pellets with microwaves, and utilizes the characteristics of microwaves such as selective heating, rapid heating, volumetric heating and activation of metallurgical chemical reactions to quickly increase the temperature of the material and accelerate the chemical reaction. Moreover, microwave heating itself does not produce gas, which reduces the amount of waste gas emissions and achieves energy conservation and emission reduction.
[0026] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:
[0027] The present invention firstly compounds zinc-containing dust material, tar residue, biomass and bentonite to prepare zinc-containing dust pellets, and then reduces them by microwave heating to obtain reduced dezincified pellets, which significantly improves the dezincification rate, has simple operation, low energy consumption, low cost, and effectively reduces fossil energy consumption and carbon emissions, thus achieving waste treatment with waste, energy conservation and emission reduction. DETAILED DESCRIPTION
[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0029] Example 1
[0030] The method for reducing and dezincifying zinc-containing dust specifically comprises the following steps:
[0031] (1) firstly add 20% of the total weight of tar residue, 40% of straw, 1% of bentonite and 5% of water to blast furnace dust, mix them evenly, then place them in a disc pelletizing machine for 10 minutes, and then place them in a 120° C. oven for drying for 30 minutes to obtain zinc-containing dust pellets with a particle size of 8 mm;
[0032] (2) The zinc-containing dust pellets are placed in a microwave reduction furnace, heated to 1000° C. for reduction for 2 h, and then cooled in an oxygen-free environment to obtain reduced dezincified pellets.
[0033] Example 2
[0034] The method for reducing and dezincifying zinc-containing dust specifically comprises the following steps:
[0035] (1) firstly add 30% of the total weight of tar residue, 30% of coconut shell, 2% of bentonite and 8% of water to the electric furnace dust, mix them evenly, then place them in a disc pelletizer for 15 minutes, and then place them in a 150° C. oven for drying for 25 minutes to obtain zinc-containing dust pellets with a particle size of 8 mm;
[0036] (2) The zinc-containing dust pellets are placed in a microwave reduction furnace, heated to 1100° C. by microwaves for reduction for 1.5 h, and then cooled in an oxygen-free environment to obtain reduced zinc-free pellets.
[0037] Example 3
[0038] The method for reducing and dezincifying zinc-containing dust specifically comprises the following steps:
[0039] (1) firstly add 40% of the total weight of tar residue, 20% of bagasse, 3% of bentonite and 10% of water to steel-making converter dust, mix them evenly, then place them in a disc pelletizer for 20 minutes, and then place them in a 180° C. oven for drying for 20 minutes to obtain zinc-containing dust pellets with a particle size of 10 mm;
[0040] (2) The zinc-containing dust pellets are placed in a microwave reduction furnace, heated to 1200° C. for reduction for 1 hour, and then cooled in an oxygen-free environment to obtain reduced dezincified pellets.
[0041] Performance Testing
[0042] The zinc-containing dust was subjected to reduction dezincification according to the methods of Examples 1-3, and the dezincification rate was calculated. The results are shown in Table 1.
[0043] Table 1 Zinc removal rate of zinc-containing dust reduction dezincification method in Example 1-3
[0044] project Example 1 Example 2 Example 3 Zinc removal rate / % 99.7 99.8 99.5
[0045] It can be seen from Table 1 that, compared with the prior art, the zinc removal rate of the zinc-containing dust reduction dezincification method of Examples 1-3 of the present invention is significantly improved, with the highest being 99.8%.
[0046] The above experiments show that the present invention first compounds zinc-containing dust materials, tar residue, biomass and bentonite to obtain zinc-containing dust pellets, and then reduces them by microwave heating to obtain reduced dezincified pellets, which significantly improves the dezincification rate, and has simple operation, low energy consumption, low cost, and effectively reduces fossil energy consumption and carbon emissions, achieving waste treatment with waste, energy conservation and emission reduction.
[0047] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for reducing and dezincifying zinc-containing dust, characterized in that: The specific steps include: (1) adding tar residue, biomass, bentonite and water to the zinc-containing dust material, mixing evenly, pelletizing, and drying to obtain zinc-containing dust pellets; (2) The zinc-containing dust pellets are reduced by microwave heating and then cooled in an oxygen-free environment to obtain reduced zinc-depleted pellets.
2. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the zinc-containing dust material is at least one of blast furnace dust, electric furnace dust and steelmaking converter dust.
3. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the amount of the tar residue is 20%-40% of the mass of the zinc-containing dust material.
4. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the biomass is at least one of straw, coconut shell and bagasse.
5. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the amount of the biomass used is 20%-40% of the mass of the zinc dust-containing material.
6. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the amount of bentonite used is 1%-3% of the mass of the zinc-containing dust material.
7. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the amount of water used is 5%-10% of the mass of the zinc dust-containing material.
8. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the pelletizing equipment is a disc pelletizing machine, the pelletizing time is 10-20 minutes, and the particle size is 8-10 mm.
9. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (1), the drying equipment is an oven, the temperature is 120-180° C., and the drying time is 20-30 min.
10. The method for reducing and dezincifying zinc-containing dust according to claim 1, characterized in that: In step (2), the microwave heating equipment is a microwave reduction furnace, the temperature is 1000-1200° C., and the time is 1-2 hours.