Method for synergistically enriching iron, gallium and scandium by using iron-manganese slag and vanadium extraction converter sludge

Abstract

The invention discloses a method for synergistically enriching iron, gallium and scandium through iron-manganese slag and vanadium extraction converter sludge, and belongs to the technical field of comprehensive utilization of metallurgical resources. The method comprises the following steps: mixing the iron-manganese slag with the vanadium extraction converter sludge, adding a reducing agent, a slag former and a fluxing agent, and carrying out reduction smelting at 1400-1500 DEG C in an inert atmosphere. By regulating and controlling reaction conditions and utilizing the characteristics of iron reduction, gallium volatilization and scandium slagging, separation and enrichment of iron, gallium and scandium are synchronously achieved in a metallurgical process, and molten iron alloy, gallium-rich smoke dust and scandium-rich slag are obtained respectively. The method is short in process, low in cost and environment-friendly, solves the problems of high difficulty in separate treatment of two types of solid wastes and low recovery rate of valuable metals, and realizes collaborative utilization of resources.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of comprehensive utilization of metallurgical resources, and particularly relates to a method for cooperatively enriching iron, gallium and scandium from iron-manganese slag and vanadium extraction converter sludge. BACKGROUND

[0002] The titanium-rich slag is subjected to molten salt chlorination to obtain chlorination waste salt and titanium tetrachloride, and the iron-manganese slag rich in iron, manganese and trace scandium and other valuable elements can be obtained after further treatment of the chlorination waste salt. The vanadium extraction converter sludge is a solid waste containing iron, vanadium, gallium and other elements generated in the process of vanadium-titanium magnetite ironmaking. Both of these two kinds of solid waste have high resource value, but due to their complex composition and various metal occurrence states, traditional treatment methods cannot achieve efficient separation and recovery, resulting in a large amount of valuable metals not being fully utilized, causing not only resource waste but also environmental pollution problems.

[0003] At present, the treatment methods for iron-manganese slag and vanadium extraction converter sludge mainly include single wet leaching and pyrometallurgical smelting, but all have limitations. Wet process usually focuses on recovering one main metal from one kind of waste, but has long process, large reagent consumption, low recovery rate of trace dispersed metals, and generates a large amount of waste liquid, which is heavy on the environment. For example, CN116855746A discloses a method for extracting metallic gallium from vanadium extraction converter sludge, which adopts a wet process of oxalic acid leaching-extraction-electrolysis. This method directly processes the original sludge by wet method, which has high acid consumption, serious impurity co-dissolution and large subsequent separation load. CN115974128A and CN115896464A respectively disclose wet processes for recovering scandium from iron-manganese slag, which purify scandia by roasting-acid leaching-multiple extraction. These methods focus on the purification of scandium, but fail to selectively enrich trace scandium into an intermediate product easy to handle at low cost and high efficiency from the complex iron-manganese slag before purification. The above-mentioned methods of directly processing the whole iron-manganese slag result in long process, large extraction load and high cost. Traditional pyrometallurgical methods mainly focus on recovering main metals such as iron and manganese, but it is difficult to selectively enrich dispersed metals such as gallium and scandium, which are easily dispersed in slag or metal phase during smelting, resulting in the loss of these high-value elements in smelting slag and the failure to achieve economic recovery.

[0004] In summary, the existing technology is limited to single metal purification in single solid waste by wet method, and cannot simultaneously treat multiple solid wastes to achieve recovery of multiple dispersed metals. Therefore, it has become a technical problem to be solved in the field to develop a method for cooperatively separating and enriching valuable metals from multiple solid wastes, which has short process, low cost and can provide high-quality enriched raw materials for subsequent refining. SUMMARY

[0005] The technical problem to be solved by the present application is that it is difficult to efficiently separate iron, gallium and scandium from iron-manganese slag and vanadium extraction converter sludge in the prior art.

[0006] To achieve the above application purposes, the technical scheme adopted by the present application is as follows.

[0007] In a first aspect, the present application provides a method for cooperatively enriching iron, gallium and scandium from iron-manganese slag and vanadium extraction converter sludge, comprising the following steps: S1. Mix iron-manganese slag, vanadium extraction converter sludge, reducing agent, slagging agent and fluxing agent uniformly to obtain mixed raw materials; S2. Place the mixed raw materials in a reactor and reduce and smelt under the conditions of inert atmosphere and 1400-1500°C to obtain molten iron, gallium-rich fume and scandium-rich slag.

[0008] In the above step S1, the mass ratio of the iron-manganese slag to the vanadium extraction converter sludge is 1:1-2.

[0009] In the above step S1, the iron-manganese slag and the vanadium extraction converter sludge are respectively crushed to 80-100 mesh before being mixed.

[0010] In the above step S1, the main chemical components of the iron-manganese slag include Fe 20-50%, Mn 3-6%, Mg 3-5%, Ca 1.5-3.0%, Al 0.2-1.0%, Ti 0.4-1.0% and Sc 0.01-2% by mass percentage.

[0011] In the above step S1, the main chemical components of the vanadium extraction converter sludge include Fe 40-70%, Zn 0-5% and Ga 0.001-0.10% by mass percentage.

[0012] In the above step S1, the reducing agent is any one of coke and coal powder; the adding amount of the reducing agent is 10-15% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

[0013] In the above step S1, the slagging agent is any one of CaO, CaCO3 and SiO2; the adding amount of the slagging agent is 5-10% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

[0014] In the above step S1, the fluxing agent is any one of Na2CO3 and Al2O3; the adding amount of the fluxing agent is 0-2% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

[0015] In the above step S2, the inert atmosphere is nitrogen or argon, and the oxygen partial pressure is controlled to be 10 -10 ~10 -12 atm.

[0016] The time of the reduction smelting in the step S2 is 1-2 hours.

[0017] In the step S2, the molten iron is directly discharged from the bottom of the reactor for steelmaking or casting.

[0018] In the step S2, the gallium-rich fume is collected by a dust collection system and further extracted as a gallium-rich raw material.

[0019] In the step S2, the scandium-rich slag is crushed and further extracted by an acid leaching or alkali leaching process as a scandium-rich raw material.

[0020] The present application has the beneficial effects that the present application proposes, for the first time, to perform collaborative pyrometallurgical smelting on two different types of complex solid wastes, i.e., iron-manganese slag and vanadium extraction converter sludge, solves the problems of high cost and long process flow in the prior art for separately treating the two types of wastes, and realizes waste-to-waste. The present application realizes directional separation and enrichment of molten iron, gallium-containing fume and scandium-containing slag by precisely regulating the reducing agent, slagging agent and smelting conditions, effectively solves the problem of efficient separation and enrichment of scattered metals from complex raw materials, and lays a foundation for subsequent low-cost and high-efficiency refining and purification.

[0021] The present application replaces the traditional multi-step wet process with a single pyrometallurgical process, avoids the use of a large amount of acid and alkali reagents and the generation of difficult-to-treat waste liquid, significantly shortens the process flow, and greatly reduces energy consumption and environmental burden. The present application can efficiently recover iron elements, realize efficient enrichment of scattered metals gallium and scandium which are easily lost in the traditional process, and greatly improve the economic value of the entire resource utilization process. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the embodiments. Unless otherwise defined, all technical terms used herein have the same meanings as understood by those skilled in the art.

[0023] The present application proposes a collaborative treatment method for iron-manganese slag and vanadium extraction converter sludge based on pyrometallurgical reduction smelting, which realizes efficient separation and enrichment of iron, gallium and scandium by regulating the smelting conditions. Specifically, the method comprises the following steps: uniformly mixing iron-manganese slag, vanadium extraction converter sludge, reducing agent, slagging agent and flux to obtain mixed raw materials; placing the mixed raw materials in a reactor and reducing smelting under the conditions of inert atmosphere and 1400-1500°C to obtain molten iron, gallium-rich fume and scandium-rich slag.

[0024] In the present application, iron is reduced to metallic iron under a strong reducing atmosphere to form a molten iron phase (molten iron alloy with Fe as the main component). Gallium is enriched in the fume or volatile phase at high temperature due to its volatility, which facilitates subsequent extraction. Scandium is directionally enriched in the slag phase and can be efficiently recovered by selective acid leaching.

[0025] In one embodiment of the present application, the reducing agent is any one of coke or coal powder, and a strong reducing environment is formed by carbon thermal reaction. The adding amount of the reducing agent is 10-15% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

[0026] In one embodiment of the present application, the slag forming agent is any one of CaO, CaCO3, SiO2; the adding amount of the slag forming agent is 5-10% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge. In the present application, the slag forming agent adjusts the basicity of the slag, and selectively captures and enriches Sc in the slag phase, preventing it from being reduced into molten iron or being lost by volatilization; at the same time, the slag forming agent can also react with impurities (such as S and P) to make them enter the slag, thereby improving the purity of the molten iron.

[0027] In one embodiment of the present application, the fluxing agent is any one of Na2CO3, Al2O3, and the fluxing agent can further reduce the melting point of the slag system and improve its fluidity; the adding amount of the fluxing agent is 0-2% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

[0028] In one embodiment of the present application, the inert atmosphere is nitrogen or argon, and the oxygen partial pressure is controlled to be 10 -10 ~10 -12 atm. The extremely low oxygen partial pressure can ensure a strong reducing environment, so that the iron oxides can be fully reduced to metallic iron, while Sc2O3 is not reduced; at the same time, controlling the oxygen partial pressure can ensure that gallium is stably volatilized in the form of Ga2O3 or Ga2O and captured by the subsequent dust collection system.

[0029] The following specific examples will be used to explain the scheme of the present application. Those skilled in the art will understand that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific techniques or conditions are not specified in the examples, they are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. If the reagents or instruments are not specified by the manufacturer, they are all conventional products that can be obtained by purchase.

[0030] Example 1: In this embodiment, the main chemical components of the iron-manganese slag include Fe 36.3%, Mn 3.5%, Mg 3.1%, Ca 1.5%, Al 1.0%, Ti 0.53%, and Sc 0.013% by mass percentage. The main chemical components of the vanadium extraction converter sludge include Fe 64.2%, Ga 0.02%, and Zn 3.26% by mass percentage.

[0031] Iron-manganese slag and vanadium extraction converter sludge are used to enrich iron, gallium and scandium. The specific steps are as follows: 50 kg of iron-manganese slag and 75 kg of vanadium extraction converter sludge are respectively crushed to 80 mesh by a ball mill, mixed uniformly, and then placed in an electric arc furnace together with 15 kg of coke, 7 kg of CaO and 1 kg of Na2CO3 for reduction smelting. The reaction conditions are set as follows: 1450°C, 1.5 h, nitrogen gas as protective gas, and oxygen partial pressure controlled at 10 -11 atm.

[0032] After the reaction is completed, 64 kg of molten iron (molten iron alloy with Fe as the main component) is obtained, and the recovery rate of the molten iron alloy is 96.5%. The yield of gallium-rich fume is 2.5 kg, and the main components are oxides or solid solutions of Ga, Zn, Fe and other elements. The recovery rate of gallium is 82.3%. The yield of scandium-rich slag is 67 kg, and the main component is a solid solution of Ca-Si-Al-Sc-Fe. The recovery rate of scandium is 86.7%.

[0033] In this embodiment, the main chemical components of the iron-manganese slag include Fe 48.9%, Mn 3.5%, Mg 3.2%, Ca 2.0%, Al 0.6%, Ti 0.48%, and Sc 0.1% by mass percentage. The main chemical components of the vanadium extraction converter sludge include Fe 68.5%, Ga 0.1%, and Zn 2.45% by mass percentage.

[0034] Iron-manganese slag and vanadium extraction converter sludge are used to enrich iron, gallium and scandium. The specific steps are as follows: 50 kg of iron-manganese slag and 75 kg of vanadium extraction converter sludge are respectively crushed to 80 mesh by a ball mill, mixed uniformly, and then placed in an electric arc furnace together with 15 kg of coke, 7 kg of CaO and 1 kg of Na2CO3 for reduction smelting. The reaction conditions are set as follows: 1450°C, 1.5 h, nitrogen gas as protective gas, and oxygen partial pressure controlled at 10 -12 atm.

[0035] After the reaction is completed, 64 kg of molten iron (molten iron alloy with Fe as the main component) is obtained, and the recovery rate of the molten iron alloy is 96.5%. The yield of gallium-rich fume is 2.5 kg, and the main components are oxides or solid solutions of Ga, Zn, Fe and other elements. The recovery rate of gallium is 82.3%. The yield of scandium-rich slag is 67 kg, and the main component is a solid solution of Ca-Si-Al-Sc-Fe. The recovery rate of scandium is 86.7%.

[0036] In this embodiment, the main chemical components of the iron-manganese slag include Fe 48.9%, Mn 3.5%, Mg 3.2%, Ca 2.0%, Al 0.6%, Ti 0.48%, and Sc 0.1% by mass percentage. The main chemical components of the vanadium extraction converter sludge include Fe 68.5%, Ga 0.1%, and Zn 2.45% by mass percentage.

[0037] The iron-manganese slag and the vanadium extraction converter sludge are used to enrich iron, gallium and scandium. The specific steps are as follows: 70 kg of iron-manganese slag and 35 kg of vanadium extraction converter sludge are respectively crushed to 80 mesh by a ball mill, and then mixed with 12 kg of coke, 10 kg of CaO and 1.2 kg of Al2O3, and then placed in an electric arc furnace for reduction smelting. The reaction conditions are set as follows: 1420°C, 2h, nitrogen gas as protective gas, and the oxygen partial pressure is controlled to be 10 -10 atm.

[0038] After the reaction is completed, 54 kg of molten iron (molten iron alloy with Fe as the main component) is obtained, and the recovery rate of the molten iron alloy is 94.8%. The yield of the gallium-rich fume is 2.8 kg, and the recovery rate of gallium is 95.6%. The yield of the scandium-rich slag is 58 kg, and the recovery rate of scandium is 89.3%.

[0039] In the embodiment, the main chemical components of the iron-manganese slag include Fe 48.5%, Mn 3.8%, Mg 4.1%, Ca 1.9%, Al 0.73%, Ti 0.56%, and Sc 1.3% by mass percentage. The main chemical components of the vanadium extraction converter sludge include Fe 65.4%, Ga 0.10%, and Zn 2.58% by mass percentage.

[0040] The iron-manganese slag and the vanadium extraction converter sludge are used to enrich iron, gallium and scandium. The specific steps are as follows: 70 kg of iron-manganese slag and 35 kg of vanadium extraction converter sludge are respectively crushed to 80 mesh by a ball mill, and then mixed with 12 kg of coke, 10 kg of CaO and 1.2 kg of Al2O3, and then placed in an electric arc furnace for reduction smelting. The reaction conditions are set as follows: 1420°C, 2h, nitrogen gas as protective gas, and the oxygen partial pressure is controlled to be 10 -10 atm, cyclone dust collection and electrostatic dust collection are used.

[0041] After the reaction is completed, 54 kg of molten iron (molten iron alloy with Fe as the main component) is obtained, and the recovery rate of the molten iron alloy is 94.8%. The yield of the gallium-rich fume is 2.8 kg, and the recovery rate of gallium is 95.6%. The yield of the scandium-rich slag is 58 kg, and the recovery rate of scandium is 89.3%.

Claims

1. A method for enriching iron, gallium and scandium from iron-manganese slag and vanadium extraction converter sludge, characterized in that, The method comprises the following steps: S1. mixing iron-manganese slag, vanadium extraction converter sludge, reducing agent, slagging agent and fluxing agent to obtain mixed raw materials; S2. placing the mixed raw materials in a reactor and reducing smelting under inert atmosphere at 1400-1500°C to obtain molten iron, gallium-rich fume and scandium-rich slag.

2. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S1, the mass ratio of the iron-manganese slag to the vanadium extraction converter sludge is 1:1-2.

3. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S1, the iron-manganese slag and the vanadium extraction converter sludge are respectively crushed to 80-100 mesh before mixing.

4. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S1, the main chemical components of the iron-manganese slag include Fe 20-50%, Mn 3-6%, Mg 3-5%, Ca 1.5-3.0%, Al 0.2-1.0%, Ti 0.4-1.0%, and Sc 0.01-2% by mass percentage. The main chemical components of the vanadium extraction converter sludge include Fe 40-70%, Zn 0-5%, and Ga 0.001-0.10% by mass percentage.

5. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S1, the reducing agent is any one of coke and coal powder; the adding amount of the reducing agent is 10-15% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

6. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S1, the slagging agent is any one of CaO, CaCO3 and SiO2; the adding amount of the slagging agent is 5-10% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

7. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag with vanadium extraction converter sludge according to claim 1, characterized in that: In step S1, the fluxing agent is any one of Na2CO3 and Al2O3; the adding amount of the fluxing agent is 0-2% of the total mass of the iron-manganese slag and the vanadium extraction converter sludge.

8. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S2, the inert atmosphere is nitrogen or argon, and the oxygen partial pressure is controlled to be 10 -10 atm. -12 atm.

9. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S2, the time of the reducing smelting is 1-2h.

10. The method for enriching iron, gallium and scandium by synergizing iron-manganese slag and vanadium extraction converter sludge according to claim 1, characterized in that: In step S2, at least one of the following conditions is met: The molten iron is directly discharged from the bottom of the reactor and used for steelmaking or casting; The gallium-rich fume is collected by a dust collection system and used as a gallium-rich raw material for further extraction of gallium; The scandium-rich slag is used as a scandium-rich raw material, crushed, and then subjected to acid leaching or alkali leaching process for further extraction of scandium.