Fuming slag recovery method

Abstract

The invention belongs to the technical field of comprehensive utilization of smelting slag resources, and particularly relates to a fuming slag recovery method which comprises the following steps: adding a reducing agent and a slag former into fuming slag, and reacting to obtain zinc-containing smoke dust, copper-containing molten iron and tailings; the recovery process is carried out in an electric heating device. According to the recovery method, copper can enter molten iron, copper-containing molten iron is obtained, and zinc is reduced to be in a metallic state, volatilized, oxidized into zinc oxide and collected in a smoke dust form; the iron content in the obtained molten iron exceeds 90%, and the zinc content in the zinc-containing smoke dust exceeds 45%. The obtained copper-containing molten iron can be used for steelmaking, the tailings can be used for preparing micro powder or mineral wool, the process is short, the metal recovery rate is high, no other solid waste is produced, and environment friendliness is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of smelting slag resources, and in particular relates to a method for recovering fumed slag. Background Art

[0002] Fuming furnaces are often used to treat lead reduction slag, tin slag, zinc smelting slag, zinc leaching slag, etc., to recover valuable metals such as zinc and lead. In the smelting process, the main slag type is often iron, silicon, and calcium oxides. In addition, it also contains a small amount of valuable metals such as zinc, lead, and copper. At present, the traditional way to treat fumed slag is to store it or sell it to cement companies as an ingredient for iron-containing raw materials. Although the application of iron resources has been achieved, the application value is relatively low. Some of the existing patent documents have also made improvements on the application of fumed slag. For example, a patent document discloses a method for utilizing fumed slag from lead and zinc smelting, which uses a countercurrent heat exchanger to cool the fumed slag into solid slag, and then grinds it and magnetically separates it to recover magnetic iron oxides. However, this method fails to fully recover the zinc resources, and the iron recovery rate is low and the grade of the iron product is low; a patent document discloses a method for preparing microcrystalline glass from fumed slag, which adds the fumed slag to the iron selection tailings, and prepares microcrystalline glass by adding other slag-forming agents, crystallizing agents, etc., and adopts high-temperature melting, water quenching and fine grinding, granulation, heat treatment and other steps. This method fails to recover valuable metals such as iron and zinc; another patent document discloses a method for comprehensive utilization of lead and zinc smelting slag resources, which mainly processes solid lead and zinc smelting slag, mixes the lead and zinc smelting slag with a slag type reconstructor, an additive, and a binder, and then presses it into a ball, and then roasts it at high temperature under solid conditions, and the lead and zinc volatilize into the smoke for recovery, wherein the iron oxides are reduced to metallic iron, and the metallic iron is melted and separated in a melting furnace to recover the metallic iron. This method has a long process flow and high energy consumption. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art in recycling fumed slag, such as high energy consumption, long process, or inability to achieve recovery and high-value application of valuable metals, thereby providing a fumed slag recovery method.

[0004] To this end, the present invention provides the following technical solutions.

[0005] The fumed slag recovery method provided by the present invention comprises the following steps: adding a reducing agent and a slag-forming agent into the fumed slag for reaction to obtain zinc-containing smoke, copper-containing molten iron and tailings; and the recovery process is carried out in an electric heating device.

[0006] Optionally, the reaction temperature is 1250-1650°C; preferably, the reaction temperature is 1350-1550°C.

[0007] Optionally, the slag-forming agent is added to make the binary basicity (CaO / SiO2) of the furnace slag obtained by the reaction be 0.4-3.0; preferably, the binary basicity of the furnace slag obtained by the reaction be 0.7-1.5.

[0008] Optionally, the mass of the reducing agent is greater than or equal to 5% of the fumed slag; preferably, the mass of the reducing agent is 5% to 30% of the fumed slag, and using too much reducing agent has no obvious beneficial effect on the recovery effect.

[0009] Optionally, the electric heating device includes an electric smelting furnace; preferably, the electric smelting furnace includes a direct current furnace, an alternating current furnace, an induction furnace, or a plasma furnace.

[0010] In the fumed slag recovery method provided by the present invention, the reducing agent and the slag-forming agent can be added to the fumed slag at the same time to react and obtain zinc-containing smoke, copper-containing molten iron and tailings.

[0011] Optionally, the recovery process is divided into two stages. In the first recovery process, the mass of the reducing agent added to the fumed slag accounts for 30% to 80% of the total mass of the reducing agent. The first reaction obtains zinc-containing smoke, the first copper-containing molten iron, and iron slag. In the second recovery process, the remaining reducing agent and slag-making agent are added to the iron slag. The second reaction obtains smoke, the second copper-containing molten iron, and tailings. The specific amount of the reducing agent can be adjusted according to the requirements for the content of each element in the first copper-containing molten iron and the second copper-containing molten iron.

[0012] Optionally, the temperature of the first stage reaction and the second stage reaction is 1250-1650° C.; preferably, the temperature of the first stage reaction and the second stage reaction is 1350-1550° C. In actual operation, the temperatures of the first stage reaction and the second stage reaction can be the same or different, and can be adaptively adjusted according to the actual situation of the slag.

[0013] Optionally, the slag-forming agent is added to make the binary basicity of the furnace slag obtained in the second stage reaction be 0.4-3.0; preferably, the binary basicity of the furnace slag obtained in the second stage reaction be 0.7-1.5.

[0014] In the fumed slag recovery method provided by the present invention, the specific selection of parameters such as reaction temperature, reducing agent dosage, binary basicity, etc. are all adaptively determined according to the composition of the fumed slag.

[0015] Optionally, during the first recovery process, a slag-forming agent is added, and the mass of the added slag-forming agent is ≤ 50% of the total mass of the slag-forming agent.

[0016] Optionally, the fumed slag is liquid fumed slag and / or cold fumed slag directly transferred from the fuming furnace. The liquid fumed slag can be transferred from the fuming furnace using a slag bag, a chute, etc. The scheme described in this case can process all liquid fumed slag, or process cold fumed slag at the same time, or process all cold fumed slag.

[0017] In the fumed slag recovery method provided by the present invention, the tailings obtained are liquid tailings, and the gas-solid mixture obtained after the reaction includes smoke and highly reducing flue gas, which can be directly burned in the furnace, flue or secondary combustion chamber to fully utilize the highly reducing flue gas, oxidize metallic zinc and lead while recovering waste heat, and finally obtain zinc-containing smoke. The gas-solid mixture obtained after the reaction can also be subjected to dust collection and flue gas purification to remove zinc-containing smoke, and the purified highly reducing flue gas obtained can be used to supply other scenes requiring combustion and heating.

[0018] Preferably, the particle size of the reducing agent and the slag-forming agent is less than 100 mm.

[0019] Optionally, the slag-forming agent includes at least one of lime, limestone, magnesite, dolomite, and calcined dolomite. The specific slag-forming agent to be used depends on the composition of the fumed slag. Typically, but not limited to, when the aluminum content in the fumed slag is high, dolomite or magnesite combined with limestone can be used as the slag-forming agent.

[0020] Optionally, the reducing agent includes at least one of anthracite, bituminous coal, coke, diesel, natural gas, coke oven gas, heavy oil, gasoline, coal gas, and hydrogen, and can be specifically selected according to the content of each component in the fumed slag and the desired effect.

[0021] In the fumed slag recovery method provided by the present invention, the fumed slag, slag-forming agent and reducing agent can be added to the furnace in a continuous or periodic manner for reaction according to actual conditions.

[0022] In the fumed slag recovery method provided by the present invention, the entire recovery method is carried out in an ore-fired furnace. According to actual conditions, when the recovery process is not segmented, it can be completed in one ore-fired furnace, that is, the steps of heating, reaction, and slag-making can be completed in one ore-fired furnace; when the recovery process is divided into two stages, it can be carried out in one ore-fired furnace in stages, or it can be completed by continuous smelting in two ore-fired furnaces. The electric heating device used can be a DC electric furnace, an AC electric furnace, an induction electric furnace, etc.

[0023] In the fumed slag recovery method provided by the present invention, the electric heating device can be operated by a closed positive pressure or a slight negative pressure, the slight negative pressure is controlled at -1Pa to -100Pa, and the closed positive pressure is controlled at 1 to 100Pa.

[0024] Optionally, the reducing agent and the slag-forming agent are added by at least one of direct input and injection. Typically, but not limited to, direct input can be input through belt conveyor at the furnace top, and injection addition can be added by setting a spray gun on the side of the furnace and using gas injection. When added by injection, the contact area between the reducing agent and the fumed slag is larger, the reaction efficiency will be higher, which is conducive to dezincification and can increase the amount of zinc recovery to a certain extent.

[0025] The beneficial effects of the present invention are: The fumed slag recovery method provided by the present invention comprises the following steps: adding a reducing agent and a slag-making agent to the fumed slag, reacting to obtain zinc-containing smoke, copper-containing molten iron, and tailings; the recovery process is carried out in an electric heating device. The method allows copper to enter molten iron to obtain copper-containing molten iron, and zinc is reduced to a metallic state and volatilized, then oxidized to zinc oxide and collected in the form of smoke. The iron resources in the fumed slag can be fully recovered, and the zinc resources therein can be deeply recovered. The obtained molten iron and zinc-containing smoke are of high quality and high value; the iron content in the obtained molten iron exceeds 90%, and the zinc content in the zinc-containing smoke exceeds 45%. The recovery rates of iron, zinc, and copper can exceed 95%, and the recovery rate of lead can exceed 85%. The obtained copper-containing molten iron can be used to smelt steel with certain requirements for copper content, and can also be partially added to ordinary steel with lower requirements for copper content. The tailings can be used to prepare micropowder or slag wool, with a short process, a high metal recovery rate, no other solid waste output, and environmental friendliness.

[0026] The fumed slag recovery method provided by the present invention can divide the recovery process into two stages. In the first recovery process, the mass of the reducing agent added to the fumed slag accounts for 30% to 80% of the total reducing agent mass, and the reaction is performed to obtain zinc-containing smoke dust, the first copper-containing molten iron, and iron slag; in the second recovery process, the remaining reducing agent and slag-making agent are added to the iron slag, and the reaction is performed to obtain smoke dust, the second copper-containing molten iron, and tailings. In the first recovery process, most of the zinc, copper, lead and part of the iron are selectively reduced, and the copper content of the obtained first copper-containing molten iron is relatively high; in the second recovery process, the remaining metals are deeply recovered, and the copper content of the obtained second copper-containing molten iron is relatively low. The recovery process can be segmented or not segmented according to the demand for the copper content in the molten iron during recycling, and a higher quality product can be obtained with less energy.

[0027] In the fumed slag recovery method provided by the present invention, a slag-forming agent is added during the first recovery process, and the mass of the added slag-forming agent is ≤ 50% of the total mass of the slag-forming agent, which can help control the amount of iron recovered and further control the relative contents of iron and copper in the copper-containing molten iron to obtain the target product.

[0028] The fumed slag recovery method provided by the present invention is a liquid fumed slag and / or cold fumed slag directly transferred from a fuming furnace. When the liquid fumed slag is used, the remaining heat is fully utilized, the energy used for heating is reduced, the melting energy consumption is saved, and the efficient utilization of energy is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 This is a schematic diagram of the recovery process of Example 1 of the present invention; Figure 2 This is a schematic diagram of the recovery process of Example 4 of the present invention. DETAILED DESCRIPTION

[0031] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0032] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0033] The detection methods for each element in the product are all chemical analysis detection methods. The determination method for the content of each element in tailings refers to GB / T 14353.1-2010 and GB / T 6730.6-2016. The determination method for the content of each element in copper-containing molten iron refers to YS / T 990.1-2014, GB / T 223.64-2008, and GB / T 20123-2006. The determination method for the content of each element in zinc-containing smoke refers to YS / T 1512.1-2021.

[0034] Experimental drugs The composition of the fumed slag used is shown in Table 1.

[0035] Table 1

[0036] Example 1 This embodiment provides a method for recovering fumed slag. See the schematic diagram of the process. Figure 1 , as follows: Anthracite is used as the reducing agent and lime is used as the slagging agent, which are crushed to a particle size of less than 100 mm.

[0037] The liquid fumed slag is intermittently flowed into the ore-fired furnace through a chute, and the reducing agent and slag-forming agent are continuously added into the furnace through the charging port on the furnace top by a belt. The amount of reducing agent is 13% of the fumed slag, and the added slag-forming agent controls the binary basicity (CaO / SiO2) of the slag in the furnace obtained by the reaction to be 1. The reaction temperature is 1500℃.

[0038] After the reaction, copper-containing molten iron, tailings, and a gas-solid mixture are separated and the gas-solid mixture is continuously introduced into a secondary combustion chamber for full combustion to obtain zinc-containing smoke.

[0039] In the tailings: iron content is 1%, zinc content is 0.005%, and copper content is 0.02%.

[0040] The copper-containing molten iron has the following contents: copper content 1.75%, carbon content 1.5%, manganese content 2%, iron content 94.92%, and S content 0.06%. The copper-containing molten iron can be used to smelt 1%~3% S30480 stainless steel or 1%~2% copper-containing S31782 stainless steel.

[0041] Zinc content in zinc-containing dust is 48.2%, which can be directly supplied to zinc smelters as raw materials.

[0042] The recovery rate of each element is calculated using the formula "(weight of elements in raw materials - weight of elements in tailings) / weight of elements in raw materials": the recovery rate of iron in molten iron is 97.35%, the recovery rate of copper is 97.21%, and the recovery rate of zinc in smoke is 99.69%.

[0043] The fumed slag recovery method can process 100,000 tons of liquid fumed slag annually.

[0044] Example 2 This embodiment provides a method for recovering fumed slag, which is different from the embodiment 1 only in that bituminous coal is used as a reducing agent, the amount of the reducing agent is 11% of the fumed slag, the added slag-forming agent controls the binary basicity of the slag obtained by the reaction to be 0.8, and the reaction temperature is 1450° C. The specific content of each element in the obtained product is as follows.

[0045] In the tailings: iron content is 2.5%, zinc content is 0.01%, and copper content is 0.04%.

[0046] The copper-containing molten iron has the following contents: copper content 1.77%, carbon content 1.5%, manganese content 0.5%, iron content 95.78%, and S content 0.16%. The copper-containing molten iron can be used to smelt 1%~3% S30480 stainless steel or 1%~2% copper-containing S31782 stainless steel.

[0047] Zinc content in zinc-containing dust is 46.5%, which can be directly supplied to zinc smelters as raw materials.

[0048] Recovery rates of each element: iron recovery rate in molten iron is 95.24%, copper recovery rate is 95.3%, and zinc recovery rate in smoke is 99.34%.

[0049] The fumed slag recovery method can process 100,000 tons of liquid fumed slag annually.

[0050] Example 3 This embodiment provides a method for recovering fumed slag, which is different from the first embodiment in that coke is used as a reducing agent, the amount of the reducing agent is 20% of the fumed slag, the added slag-forming agent controls the binary basicity of the slag in the furnace obtained by the reaction to be 1.2, the reaction temperature is 1650°C, and the reducing agent and the slag-forming agent are continuously added to the furnace by spraying using a spray gun. The specific content of each element in the obtained product is as follows.

[0051] In the tailings: iron content is 0.4%, zinc content is 0.0009%, and copper content is 0.01%.

[0052] The copper-containing molten iron has the following contents: copper content 1.71%, carbon content 4%, manganese content 2.5%, iron content 91.56%, and S content 0.006%. The copper-containing molten iron can be used to smelt 1%~3% S30480 stainless steel or 1%~2% copper-containing S31782 stainless steel.

[0053] Zinc-containing dust contains 49.5% zinc, which can be directly supplied to zinc smelters as raw materials.

[0054] Recovery rates of various elements: iron recovery rate in molten iron is 98.84%, copper recovery rate is 98.10%, and zinc recovery rate in smoke is 99.94%.

[0055] The fumed slag recovery method can process 100,000 tons of liquid fumed slag annually.

[0056] Example 4 This embodiment provides a method for recovering fumed slag. See the schematic diagram of the process. Figure 2 , as follows: Anthracite is used as the reducing agent and lime is used as the slagging agent, which are crushed to a particle size of less than 100 mm.

[0057] A submerged arc furnace is used for treatment, so that the liquid fumed slag flows into the submerged arc furnace intermittently through the chute. In the first stage of recovery, the reducing agent is continuously added to the furnace through the furnace top charging port by a belt. The amount of reducing agent is 70% of the total amount of reducing agent. The first stage reaction temperature is 1450℃. After reaction, the first gas-solid mixture, the first copper-containing molten iron, and iron slag are separated. The first gas-solid mixture is continuously introduced into the second combustion chamber for full combustion to obtain zinc-containing smoke. The first copper-containing molten iron is released, and the remaining iron slag is subjected to the second stage of recovery. The reducing agent and slag-making agent are continuously added to the furnace through the furnace top charging port by a belt. The total amount of reducing agent is 13% of the fumed slag. The added slag-making agent controls the binary basicity of the furnace slag obtained by the reaction to be 1. The second stage reaction temperature is 1500℃. After reaction, the second gas-solid mixture, the second copper-containing molten iron, and tailings are separated. The second gas-solid mixture is continuously introduced into the second combustion chamber for full combustion to obtain smoke, which is returned to the submerged arc furnace for treatment as a raw material.

[0058] Iron slag contains: iron content 20%, copper content 0.05%, and zinc content 0.03%.

[0059] In the tailings: iron content is 1%, copper content is 0.02%, and zinc content is 0.005%.

[0060] The first copper-containing molten iron has a copper content of 2.53%, a carbon content of 1%, and an iron content of 96.14%. It can be used to smelt S30480 stainless steel containing 1% to 3% copper.

[0061] The second copper-containing molten iron has a copper content of 0.16%, a carbon content of 3%, a manganese content of 1%, and an iron content of 95.6%. It can be used as ordinary molten iron for steelmaking.

[0062] Zinc content in zinc-containing dust is 47.5%, which can be directly supplied to zinc smelters as raw materials.

[0063] The zinc content in the smoke is 1.5%. Since the zinc content is too low, it cannot be supplied to manufacturers for use and can only be returned to the ore-fired furnace as raw material for treatment.

[0064] Recovery rates of each element: iron recovery rate in molten iron is 97.84%, copper recovery rate is 97.49%, and zinc recovery rate in smoke is 98.56%.

[0065] The fumed slag recovery method can process 100,000 tons of liquid fumed slag annually.

[0066] Example 5 This embodiment provides a method for recovering fumed slag, which differs from the embodiment 4 only in that, in the first recovery process, a slag-forming agent is added which accounts for 50% of the total mass of the slag-forming agent used. The specific content of each element in the obtained product is as follows.

[0067] Iron slag contains: iron content 18%, copper content 0.04%, and zinc content 0.02%.

[0068] In the tailings: iron content is 0.9%, copper content is 0.02%, and zinc content is 0.006%.

[0069] The first copper-containing molten iron has a copper content of 2.58%, a zinc content of 0.006%, a carbon content of 0.9%, and an iron content of 96.14%. It can be used to smelt S30480 stainless steel containing 1% to 3% copper.

[0070] The second copper-containing molten iron has the following contents: copper content 0.13%, carbon content 2.8%, zinc content 0.003%, manganese content 0.9%, and iron content 95.6%. It can be used as ordinary molten iron for steelmaking.

[0071] Zinc-containing dust contains 48.1% zinc, which can be directly supplied to zinc smelters as raw materials.

[0072] The zinc content in the smoke is 3.1%. Due to the low zinc content, it cannot be supplied to manufacturers for use and can only be returned to the ore-fired furnace as raw material for processing.

[0073] Recovery rates of various elements: iron recovery rate in molten iron is 97.7%, copper recovery rate is 97.41%, and zinc recovery rate in smoke is 98.88%.

[0074] The fumed slag recovery method can process 100,000 tons of liquid fumed slag annually.

[0075] It can be seen from the above embodiments and related data that the fumed slag recovery method provided by the present invention has a good effect in an electric furnace. When using the method of adding all the reducing agents and slag-making agents to the fumed slag at the same time to react, even if a lower temperature and reducing agent ratio are used in Example 2, the iron recovery rate can be 95.24%, the copper recovery rate can be 95.3%, and the zinc recovery rate can be 99.34%. The recovery rate of each element is already very high. In Example 3, a higher temperature and reducing agent ratio are used, and the iron recovery rate is as high as 98.84%, the copper recovery rate is as high as 98.10%, and the zinc recovery rate is as high as 99.94%, further improving the recovery rate of each element. Moreover, binary alkalinity will affect the sulfur content in molten iron. The higher the alkalinity, the lower the sulfur content in molten iron; the amount of reducing agent will affect the carbon content in molten iron. When the reducing agent ratio is low, the carbon content in molten iron is low; in actual operation, it can be adjusted according to the required adaptability of molten iron composition. When the method of dividing the recovery process into two stages is used, the recovery rate of zinc will decrease to a certain extent, which is 98.56% in Example 4 and 98.88% in Example 5. This is because the zinc content in the smoke obtained by the second stage reaction is too low to be used directly. However, the smoke obtained will be returned as raw material for processing, so there is no waste.

[0076] If slag-forming agent is not added during the reaction, the separation effect of slag and iron will be poor after reduction, and the sulfur content will be too high.

[0077] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. A method for recovering fumed slag, characterized in that: The steps include: Adding a reducing agent and a slag-making agent to the fumed slag to react and obtain zinc-containing smoke, copper-containing molten iron and tailings; The recovery process takes place in an electrothermal unit.

2. The recycling method according to claim 1, characterized in that: The reaction temperature is 1250-1650°C; preferably, the reaction temperature is 1350-1550°C; and / or, adding the slag-forming agent to make the binary basicity of the furnace slag obtained by the reaction to be 0.4-3.0; preferably, making the binary basicity of the furnace slag obtained by the reaction to be 0.7-1.5; And / or, the mass of the reducing agent is greater than or equal to 5% of the fumed slag; preferably, the mass of the reducing agent is 5% to 30% of the fumed slag; And / or, the electric heating device includes an electric smelting furnace; preferably, the electric smelting furnace includes a direct current furnace, an alternating current furnace, an induction furnace, or a plasma furnace.

3. The recovery method according to claim 1 or 2, characterized in that: The recovery process is divided into two stages. In the first recovery process, the mass of the reducing agent added to the fumed slag accounts for 30% to 80% of the total reducing agent mass. In the first reaction, zinc-containing smoke, the first copper-containing molten iron, and iron slag are obtained. In the second recovery process, the remaining reducing agent and slag-forming agent are added to the iron slag. In the second reaction, smoke, the second copper-containing molten iron, and tailings are obtained.

4. The recycling method according to claim 3, characterized in that: The temperature of the first stage reaction and the second stage reaction is 1250-1650°C; preferably, the temperature of the first stage reaction and the second stage reaction is 1350-1550°C; And / or, the slag-forming agent is added to make the binary basicity of the furnace slag obtained in the second stage reaction be 0.4-3.0; preferably, the binary basicity of the furnace slag obtained in the second stage reaction be 0.7-1.

5.

5. The recovery method according to claim 3 or 4, characterized in that: During the first recovery process, a slag-forming agent is added, and the mass of the added slag-forming agent is ≤ 50% of the total mass of the slag-forming agent.

6. The recycling method according to any one of claims 1 to 5, characterized in that: The fumed slag is liquid fumed slag and / or cold fumed slag directly transferred from a fuming furnace.

7. The recycling method according to any one of claims 1 to 6, characterized in that: The particle size of the reducing agent and the slag-forming agent is less than 100 mm.

8. The recycling method according to any one of claims 1 to 7, characterized in that: The slag-forming agent includes at least one of lime, limestone, magnesite, dolomite and calcined dolomite.

9. The recycling method according to any one of claims 1 to 8, characterized in that: The reducing agent includes at least one of anthracite, bituminous coal, coke, diesel, natural gas, coke oven gas, heavy oil, gasoline, coal-to-gas, and hydrogen.

10. The recycling method according to any one of claims 1 to 9, characterized in that: The reducing agent and the slag-forming agent are added by at least one of direct injection and injection.

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