Method for recovering zinc and iron from zinc-iron-containing material in one step

Abstract

The invention belongs to the technical field of recycling of materials containing zinc and iron, and particularly relates to a method for recycling zinc and iron from materials containing zinc and iron in one step. The method is used for treating the zinc-iron-containing material by using a side-blown molten pool smelting furnace, and comprises the following steps: adding a slag former and a reducing agent into a molten pool of the zinc-iron-containing material, blowing oxygen-enriched air and fuel through a primary air spray gun, and smelting in the molten pool to obtain molten iron, tailings, smoke dust and flue gas; the binary alkalinity CaO / SiO2 in the slag is controlled to be 0.3-1.2; the main component contained in the smoke dust comprises zinc oxide; the side-blown molten pool smelting furnace comprises a first spray gun and a second spray gun, and the second spray gun is arranged in a hearth, located above a molten pool, 5-1000 mm away from the surface of the molten pool and used for combusting combustible gas in smoke. And the first spray gun is arranged on a slag layer in the molten pool. According to the method, zinc, iron and other valuable metals in the zinc-iron-containing material can be fully recovered at the same time only through one-step smelting.

Description

Technical Field

[0001] The invention belongs to the technical field of recycling zinc-iron materials, and specifically relates to a one-step method for recycling zinc and iron from zinc-iron materials. Background Art

[0002] A large amount of liquid zinc-iron slag or zinc-iron cold material will be produced in industrial production, in which the iron content can reach 20%~50%. The general treatment method for the above-mentioned zinc-iron material includes using a rotary kiln or a fuming furnace. However, when using a rotary kiln to treat the above-mentioned zinc-iron material, there will be problems such as the inability to fully recover the iron, the low purity of the iron-containing product obtained, and the serious ring formation of the rotary kiln. When using a fuming furnace to treat the above-mentioned zinc-iron material, the zinc recovery effect is better, but a large amount of iron will remain in the tailings and cannot be effectively recovered. In the prior art, there is also a method of reacting the zinc-iron material first and then flotation, but this method has a long process flow, a high amount of additives used, and a high overall cost. Summary of the invention

[0003] Therefore, the object of the present invention is to provide a method for recovering zinc and iron from zinc-iron materials in one step. The method can fully recover zinc and iron in the zinc-iron materials through a shorter process flow, and the obtained iron-containing products and zinc-containing products have high purity, so the zinc-iron materials can be fully utilized.

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

[0005] The invention provides a one-step method for recovering zinc and iron from zinc-containing iron materials. The method uses a side-blown molten pool smelting furnace to process the zinc-containing iron materials, and comprises the following steps: adding a slag-forming agent and a reducing agent into a molten pool of the zinc-containing iron materials, and spraying oxygen-enriched air and fuel, smelting in the molten pool to obtain molten iron, tailings, smoke and flue gas; controlling the binary basicity CaO / SiO2 in the slag to be 0.3-1.2; the metal contained in the smoke comprises zinc; the side-blown molten pool smelting furnace comprises a first spray gun and a second spray gun, the second spray gun is arranged in a furnace, is located above the molten pool, is 5-1000 mm away from the surface of the molten pool, and is used to burn combustible gas in the smoke; the first spray gun is arranged in a slag layer in the molten pool.

[0006] Optionally, in the flue gas exiting the side-blowing molten pool smelting furnace, CO accounts for 0.1% to 60% of the sum of CO and CO2, calculated on a molar basis.

[0007] In the one-step method for recovering zinc and iron from zinc-iron materials provided by the present invention, the flexibly controlled molten pool atmosphere and furnace atmosphere can be adapted to different reduction degree requirements and heat supplementation methods, and the carbon content in the final molten iron can be controlled by fine-tuning the amount of fuel and reducing agent.

[0008] Optionally, the binary basicity CaO / SiO2 in the slag is controlled to be 0.8~1.2.

[0009] Optionally, the second spray gun is arranged in the furnace, above the molten pool, and 100 to 500 mm away from the surface of the molten pool.

[0010] And / or, the reducing agent includes a solid reducing agent and / or a gaseous reducing agent; optionally, the mass of the solid reducing agent is 16%~25% of the mass of the zinc-iron containing material; optionally, the molar ratio of the gaseous reducing agent to the sum of the molar amounts of zinc and iron in the zinc-iron containing material is 1~1.5:1.

[0011] Optionally, the smelting temperature is 1400~1600℃; optionally, the smelting temperature is 1450~1500℃.

[0012] Optionally, the temperature of the flue gas exiting the side-blown molten pool smelting furnace is 150-250°C higher than the molten pool temperature.

[0013] Optionally, the reducing agent and slag-forming agent are added through the first lance and / or the feeding port on the top of the side-blowing molten pool smelting furnace.

[0014] Optionally, the fuel and oxygen-enriched air are also added to the side-blown molten pool smelting furnace using the first spray gun; optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the first spray gun is 50%~100%; further optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the first spray gun is 80%~100%.

[0015] Optionally, the second spray gun is used to add oxygen-enriched air to the side-blown molten pool smelting furnace; optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the second spray gun is 21%~100%; further optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the second spray gun is 60%~90%.

[0016] Optionally, the method further includes separating the smoke and flue gas; optionally, separating the smoke and flue gas by using a dust removal method; further optionally, the dust removal method includes at least one of an electrostatic precipitator and a bag filter. Typically, but not limited to, when the CO concentration in the flue gas is high, a bag filter is used; when the CO concentration in the flue gas is low, both an electrostatic precipitator and a bag filter are used.

[0017] Optionally, the smoke and flue gas exiting the side-blowing molten pool smelting furnace are burned to recover waste heat, and / or used as fuel after dust removal, and / or separated after dust removal to obtain CO as fuel.

[0018] Optionally, the volume percentage of oxygen in the oxygen-rich atmosphere is 30% to 100%.

[0019] Optionally, the zinc-iron-containing material includes zinc-iron-containing liquid material and / or zinc-iron-containing cold material.

[0020] Optionally, the metal contained in the smoke further includes silver and / or indium.

[0021] Optionally, the slag-forming agent includes at least one of limestone, quicklime, dolomite, calcined dolomite, quartz stone, and quartz; optionally, the slag-forming agent is at least one of limestone and quicklime.

[0022] Optionally, the reducing agent includes at least one of coal, coke, biomass reducing agent, petroleum coke, hydrogen, coke oven gas, coal gas, and blast furnace gas; optionally, the reducing agent is at least one of coal powder, coke, and biomass reducing agent; wherein the biomass reducing agent includes charcoal, bamboo charcoal, straw fiber, etc.

[0023] Optionally, the fuel includes at least one of pulverized coal, natural gas, coal-to-gas, coke oven gas, blast furnace gas, coal-to-gas, petroleum coke, and coke.

[0024] Optionally, the first spray gun is 10 to 1000 mm above the surface of the molten iron in the molten pool.

[0025] Optionally, the number of the first spray guns is 1 to 100.

[0026] Optionally, the number of the second spray guns is 1 to 100.

[0027] In the one-step method for recovering zinc and iron from zinc-iron materials provided by the present invention, the obtained molten iron can be directly used for steelmaking, the smoke dust can be used for the preparation of zinc-containing products or the preparation of other corresponding valuable metals, the smoke can be used as fuel, and the tailings can meet the requirements of high-value building materials and can be used as building materials, and no waste materials will be generated in the entire recovery method.

[0028] In the one-step method for recovering zinc and iron from zinc-containing iron materials provided by the present invention, typically but not limitingly, an iron tapping port is arranged in the molten pool of the side-blown molten pool smelting furnace at a height of 10 to 300 mm from the bottom, and a slag tapping port is arranged at the lower part of the slag layer. The generated molten iron and tailings can be discharged intermittently or continuously through a siphon device. 1 to 9 iron tapping ports can be arranged, and 1 to 9 slag tapping ports can be arranged. A front bed can also be arranged at the rear end of the side-blown molten pool smelting furnace to promote the deep separation of slag and iron.

[0029] The beneficial effects of the present invention are: The one-step zinc-iron recovery method of zinc-iron materials provided by the present invention uses a side-blown molten pool smelting furnace to process zinc-iron materials, comprising the following steps: adding a slag-making agent and a reducing agent to the zinc-iron material molten pool, and spraying oxygen-enriched air and fuel, smelting in the molten pool to obtain molten iron, tailings, smoke and flue gas; the metal contained in the smoke includes zinc; the side-blown molten pool smelting furnace includes a first spray gun and a second spray gun, the second spray gun is arranged in the furnace, located above the molten pool, 5 to 1000 mm away from the surface of the molten pool, and is used to burn the combustible gas in the flue gas; the first spray gun is arranged in the slag layer in the molten pool. The method can fully recover zinc, iron and other valuable metals in the zinc-iron materials at the same time through only one-step smelting, with a zinc recovery rate exceeding 99% and an iron recovery rate exceeding 90%. The second lance is set in the furnace, above the molten pool, 5-1000mm away from the surface of the molten pool, and is used to burn the combustible gas in the flue gas. On the one hand, it is to supplement the heat of the molten pool. On the other hand, it can also help the volatilized zinc to be quickly oxidized into metal oxides, avoiding the solidification and bonding of zinc metal in the flue due to its low melting point, thereby improving the recovery rate of zinc. The side-blown molten pool smelting furnace is used for processing. The tumbling of the molten pool in the side-blown molten pool smelting furnace can promote the rapid reaction between zinc-containing iron materials, slag-making agents, and reducing agents, thereby improving the overall efficiency. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] The detection methods of each element in the product are all chemical analysis detection methods. The determination methods of the content of each element in tailings refer to GB / T 6730.6-2016 and GB / T 14353.3-2010, the determination methods of the content of each element in molten iron refer to GB / T223.70-2008 and GB / T 20123-2006, and the determination methods of the content of each element in smoke refer to YS / T 1512.3-2021. The recovery rate of each element is calculated using the formula "(weight of element in raw material - weight of element in tailings) / weight of element in raw material".

[0033] Experimental drugs The composition of the liquid zinc-containing iron slag used is shown in Table 1.

[0034] Table 1

[0035] Example 1 This embodiment provides a one-step method for recovering zinc and iron from zinc-containing iron materials, using a side-blowing enhanced molten pool smelting furnace, on which 5 first spray guns are arranged. During smelting, the first spray guns extend into the slag layer and are located 100-200 mm above the surface of the molten iron; 5 second spray guns are arranged and are located above the molten pool and 300 mm away from the surface of the molten pool. The specific smelting steps are as follows: Liquid zinc-containing iron slag as shown in Table 1 is introduced into the side-blowing enhanced molten pool smelting furnace. The temperature of the liquid zinc-containing iron slag when introduced is 1200°C. The slag-making agent quicklime is added through the charging port on the top of the furnace. The reducing agent pulverized coal, fuel pulverized coal, and oxygen-enriched air with an oxygen volume percentage of 80% are blown in through the first spray gun. The oxygen-enriched air with an oxygen volume percentage of 80% is blown in through the second spray gun. The amount of reducing agent pulverized coal is 20% of the mass of the liquid zinc-containing iron slag. The oxygen-enriched atmosphere of the entire smelting is controlled to be about 75% by volume of oxygen. The binary basicity CaO / SiO2 in the slag is 0.9, and the smelting temperature is 1500°C. The smoke and flue gas out of the molten pool are ignited by the second spray gun, and the waste heat is recovered while helping the elemental zinc to be oxidized into zinc oxide. The temperature of the flue gas out of the furnace is controlled to be 200°C higher than that of the molten pool. In the flue gas out of the furnace, CO accounts for 50% of the sum of CO and CO2 in terms of molar amount. The smelting process produces molten iron, tailings, smoke and flue gas. The molten iron can be used directly for steelmaking, and the tailings can be used in the construction industry. The smoke and flue gas are separated by bag dust removal, and the zinc-containing smoke is used for the preparation of zinc-containing products; the smoke is used as fuel to provide heat for the smelting system and other equipment.

[0036] The iron content in the tailings is 1%, and the zinc content is 0.05%.

[0037] Iron content in molten iron: 95.51%, carbon content: 4.0%; iron recovery rate: 93.3%.

[0038] Zinc content in smoke: 64.92%; zinc recovery rate: 99.7%.

[0039] Example 2 This embodiment provides a one-step method for recovering zinc and iron from zinc-containing iron materials, using the same side-blowing enhanced molten pool smelting furnace as in Example 1. The specific smelting steps are as follows: Liquid zinc-containing iron slag as shown in Table 1 is introduced into the side-blowing enhanced molten pool smelting furnace. The temperature of the liquid zinc-containing iron slag when introduced is 1200°C. Limestone, a slag-making agent, is added through the charging port on the top of the furnace. Reducing agent coke, fuel pulverized coal, and oxygen-enriched air with an oxygen volume percentage of 80% are blown in through the first spray gun. Oxygen-enriched air with an oxygen volume percentage of 60% is blown in through the second spray gun. The amount of reducing agent coke is 16% of the mass of the liquid zinc-containing iron slag. The oxygen-enriched atmosphere of the entire smelting is controlled to be about 70% by volume of oxygen. The binary basicity CaO / SiO2 in the slag is 1.2, and the smelting temperature is 1450°C. The smoke and flue gas out of the molten pool are ignited by the second spray gun, which recovers the waste heat while helping the elemental zinc to be oxidized into zinc oxide. The temperature of the flue gas out of the furnace is controlled to be 150°C higher than that of the molten pool. In the flue gas out of the furnace, CO accounts for 30% of the sum of CO and CO2 in terms of molar amount. The smelting produces molten iron, tailings, smoke and flue gas. The molten iron can be directly used for steelmaking, and the tailings can be used in the construction industry. The smoke and flue gas are separated by electrostatic precipitators and bag dust collectors. The zinc-containing smoke is used for the preparation of zinc-containing products, and the flue gas is returned to provide heat for the smelting system.

[0040] The iron content in the tailings is 1.5%, and the zinc content is 0.1%.

[0041] Iron content in molten iron: 97.07%, carbon content: 2.5%; iron recovery rate: 90.51%.

[0042] Zinc content in smoke: 56.97%; zinc recovery rate: 99.42%.

[0043] Example 3 This embodiment provides a one-step method for recovering zinc and iron from zinc-containing iron materials, using the same side-blowing enhanced molten pool smelting furnace as in Example 1. The specific smelting steps are as follows: Liquid zinc-containing iron slag as shown in Table 1 is introduced into the side-blowing enhanced molten pool smelting furnace. The temperature of the liquid zinc-containing iron slag when introduced is 1200°C. Limestone, a slag-making agent, is added through the charging port on the top of the furnace. Reducing agent coke, fuel pulverized coal, and oxygen-enriched air with an oxygen volume percentage of 95% are blown in through the first spray gun. Oxygen-enriched air with an oxygen volume percentage of 90% is blown in through the second spray gun. The amount of reducing agent coke is 25% of the mass of the liquid zinc-containing iron slag. The oxygen-enriched atmosphere of the entire smelting is controlled to be about 90% by volume of oxygen. The binary basicity CaO / SiO2 in the slag is 1, and the smelting temperature is 1500°C. The smoke and flue gas out of the molten pool are ignited by the second spray gun, which recovers the waste heat while helping the elemental zinc to be oxidized into zinc oxide. The temperature of the flue gas out of the furnace is controlled to be 250°C higher than that of the molten pool. In the flue gas out of the furnace, CO accounts for 60% of the sum of CO and CO2 in terms of molar amount. The smelting process produces molten iron, tailings, smoke and flue gas. The molten iron can be directly used for steelmaking, and the tailings can be used in the construction industry. The smoke and flue gas are separated by bag dust removal, and the zinc-containing smoke is used for the preparation of zinc-containing products. The flue gas is used as fuel to provide heat for the smelting system and other equipment.

[0044] The iron content in the tailings is 0.5%, and the zinc content is 0.01%.

[0045] Iron content in molten iron: 95.2%, carbon content: 4.2%; iron recovery rate: 95.2%.

[0046] Zinc content in smoke: 69.82%; zinc recovery rate: 99.94%.

[0047] Obviously, the above embodiments are merely examples for 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 zinc and iron from zinc-containing iron materials in one step, characterized in that: The side-blown molten pool smelting furnace is used to process zinc-containing iron materials, including the following steps: Adding slag-making agent and reducing agent into the molten pool of zinc-iron material, and injecting oxygen-enriched air and fuel, smelting in the molten pool to obtain molten iron, tailings, smoke and flue gas; Control the binary basicity CaO / SiO2 in the slag to 0.3~1.2; The metals contained in the smoke include zinc; The side-blown molten pool smelting furnace comprises a first spray gun and a second spray gun, wherein the second spray gun is arranged in the furnace, located above the molten pool, and 5 to 1000 mm away from the surface of the molten pool, and is used to burn the combustible gas in the flue gas; The first lance is disposed at a slag layer in the molten pool.

2. The one-step method for recovering zinc and iron from zinc-containing iron materials according to claim 1, characterized in that: In the flue gas from the side-blowing molten pool smelting furnace, CO accounts for 0.1% to 60% of the sum of CO and CO2 in terms of molar amount; and / or, controlling the binary basicity CaO / SiO2 in the slag to be 0.8-1.2; And / or, the second spray gun is arranged in the furnace, above the molten pool, and 100-500 mm away from the surface of the molten pool; And / or, the reducing agent includes a solid reducing agent and / or a gaseous reducing agent; optionally, the mass of the solid reducing agent is 16%~25% of the mass of the zinc-iron containing material; optionally, the molar ratio of the gaseous reducing agent to the sum of the molar amounts of zinc and iron in the zinc-iron containing material is 1~1.5:

1.

3. The one-step method for recovering zinc and iron from zinc-containing iron materials according to claim 1 or 2, characterized in that: The smelting temperature is 1400-1600°C; optionally, the smelting temperature is 1450-1500°C; And / or, the temperature of the flue gas exiting the side-blown molten pool smelting furnace is 150-250°C higher than the molten pool temperature.

4. The one-step method for recovering zinc and iron from zinc-containing iron materials according to any one of claims 1 to 3, characterized in that: The reducing agent and slag-forming agent are added through the first lance and / or the feeding port on the top of the side-blowing molten pool smelting furnace; and / or, the fuel and oxygen-enriched air are further added to the side-blown molten pool smelting furnace using the first spray gun; optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the first spray gun is 50% to 100%; further optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the first spray gun is 80% to 100%; And / or, using the second spray gun to add oxygen-enriched air to the side-blown molten pool smelting furnace; optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the second spray gun is 21%~100%; further optionally, the volume percentage of oxygen in the oxygen-enriched air added to the side-blown molten pool smelting furnace by the second spray gun is 60%~90%.

5. The one-step method for recovering zinc and iron from zinc-containing iron materials according to any one of claims 1 to 4, characterized in that: The method further includes the step of separating the smoke dust and the flue gas; optionally, the smoke dust and the flue gas are separated by a dust removal method; further optionally, the dust removal includes at least one of an electrostatic precipitator and a bag dust collector.

6. The one-step method for recovering zinc and iron from zinc-containing iron materials according to any one of claims 1 to 5, characterized in that: The smoke and flue gas exiting the side-blowing molten pool smelting furnace are burned to recover waste heat, and / or used as fuel after dust removal, and / or separated after dust removal to obtain CO as fuel.

7. The one-step method for recovering zinc and iron from zinc-containing iron materials according to any one of claims 1 to 6, characterized in that: The oxygen volume percentage in the oxygen-enriched atmosphere is 30% to 100%; And / or, the zinc-iron-containing material includes a zinc-iron-containing liquid material and / or a zinc-iron-containing cold material; And / or, the metal contained in the smoke further includes silver and / or indium.

8. The one-step method for recovering zinc and iron from zinc-containing iron materials according to any one of claims 1 to 7, characterized in that: The slag-forming agent includes at least one of limestone, quicklime, dolomite, calcined dolomite, quartz stone, and quartz; optionally, the slag-forming agent is at least one of limestone and quicklime; And / or, the reducing agent includes at least one of coal, coke, biomass reducing agent, petroleum coke, hydrogen, coke oven gas, coal gas, and blast furnace gas; optionally, the reducing agent is at least one of coal powder, coke, and biomass reducing agent; And / or, the fuel includes at least one of pulverized coal, natural gas, coal-to-gas, coke oven gas, blast furnace gas, coal-to-gas, petroleum coke, and coke.

9. The one-step method for recovering zinc and iron from zinc-containing iron materials according to any one of claims 1 to 8, characterized in that: The first spray gun is 10-1000 mm above the surface of the molten iron in the molten pool.

10. The one-step method for recovering zinc and iron from zinc-containing iron materials according to any one of claims 1 to 9, characterized in that: The number of the first spray guns is 1 to 100; And / or, the number of the second spray guns is 1 to 100.

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