Method for separating and enriching iron and zinc by activating and roasting copper slag

Abstract

The invention relates to the technical field of hydrometallurgy, and provides a method for separating and enriching iron and zinc by activating and roasting copper slag, which comprises the following steps: activating and roasting a mixture containing copper slag, a reducing agent and a dissociation agent at 700-1000 DEG C to obtain roasted sand; mixing the roasted product with an acid solution to obtain ore pulp with the pH value of 2.5-4 and the mass concentration of 15-25%, and carrying out ball-milling leaching and solid-liquid separation on the ore pulp under the condition that the ball-to-material ratio is (3-6): 1 to obtain iron-containing filter residues and zinc-containing filtrate. According to the method, the zinc leaching rate is remarkably increased, efficient separation of iron and zinc is achieved, namely, high-value recovery of iron and full recovery of zinc are achieved at the same time, and the technical problems that in an existing copper slag recovery process, metal such as iron and zinc is difficult to separate, the process temperature is high, and energy consumption is high are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy, and particularly relates to a method for activating roasting, separating and enriching iron and zinc from copper slag. Background Art

[0002] In the pyrometallurgical copper smelting process, 2.2 - 3 tons of copper slag are produced for every ton of copper produced. As a metallurgical by-product, the component characteristics of copper slag are rich in metals such as iron, zinc, and copper. Specifically, copper slag contains 30 - 45% iron, 0.5% - 4.6% copper, and 1 - 3% zinc. Copper slag is a very large and important secondary metallurgical resource. Efficiently developing and utilizing these copper slags and recycling metals such as iron and zinc in the copper slag is of great significance for the sustainable development of China's copper and steel industries. From the perspective of phase distribution, iron elements are mainly hosted in fayalite phase and magnetic iron oxide phase, and there are various forms of minerals such as zinc ferrite, copper sulfide, and metallic copper in the slag phase, along with the doping of highly toxic substances such as arsenic and lead. Such complex minerals are difficult to dissociate, exacerbating the complexity of the separation and enrichment of iron and zinc and other metals, making the recovery process face problems such as low efficiency, high energy consumption cost, and limited metal recovery rate. Currently, the main methods for recycling iron, copper, and zinc in copper slag include: (1) The flotation method is a physicochemical separation technology based on the differences in the physicochemical properties of mineral surfaces, mainly used for recovering copper and trace zinc in copper slag. The core of its process is to make the surface of the target mineral hydrophobic by adding specific reagents (such as collectors and frothers), and to achieve the selective enrichment of copper minerals under the action of bubbles. This method has the advantages of high recovery efficiency (the grade of copper concentrate can reach 29.22%), low energy consumption, and less reagent consumption, and is especially suitable for the treatment of high-grade copper slag. However, due to the complex mineral composition in copper slag, the flotation process is easily affected by the mineral dissemination characteristics and composition fluctuations, resulting in insufficient stability of copper recovery and poor recovery effect for iron elements.

[0003] (2) The wet leaching method selectively dissolves valuable metals in copper slag through chemical reagents (such as acid, alkali, or salt solutions), and can effectively recover copper, zinc, and a small amount of iron. According to different pretreatment methods, it is divided into direct leaching (direct reaction of copper slag with leaching agent) and indirect leaching (leaching after changing the slag phase structure through roasting or oxidation). This method can avoid the high energy consumption and waste gas pollution problems of the pyrometallurgical process, and is especially suitable for treating low-grade copper slag (copper content < 0.5%). However, the wet leaching has a low recovery efficiency for iron, and the continuous consumption of chemical reagents may cause problems in waste liquid treatment, posing certain environmental risks.

[0004] (3) The roasting - magnetic separation method is a combined process for iron element recovery. By means of high - temperature roasting (above 1100 °C), the non - magnetic iron oxides in copper slag are converted into magnetite or elemental iron, and then high - efficient separation of iron concentrate is achieved by using magnetic separation equipment. This method can significantly improve the iron recovery rate, and the iron concentrate grade is relatively high, being suitable for large - scale industrial applications. However, its limitations are that the energy consumption during the roasting process is relatively high, and sulfur - containing or carbon - containing waste gases may be released. At the same time, some copper, zinc, and iron in the reduced iron powder cannot be separated effectively, and other valuable metals such as copper and zinc cannot be recovered efficiently.

[0005] (4) The pyrometallurgical impoverishment method enriches valuable metals in copper slag through high - temperature reduction or sulfidation reactions (1200 - 1300 °C), mainly including two processes: return remelting (matte returns to the main smelting process) and reduction to matte (separately recovering metals such as cobalt and nickel). This method can efficiently recover copper (copper content in slag is reduced to below 0.35%), and simultaneously extract associated metals such as cobalt and nickel, featuring a short process flow and high waste heat utilization rate. However, its main drawbacks are relatively high energy consumption (relying on electric furnaces or natural gas for heating), and sulfur - containing and dust - containing waste gases are easily generated during the high - temperature process, and a flue gas purification system needs to be equipped to reduce the environmental load.

[0006] Based on the above analysis, traditional flotation methods, hydrometallurgical leaching methods, roasting - magnetic separation methods, and pyrometallurgical impoverishment methods all have obvious deficiencies in recovering valuable elements such as copper, zinc, and iron in copper slag. The flotation process is more suitable for recovering copper in the slag. The hydrometallurgical process has a low iron recovery efficiency, and the continuous consumption of chemical reagents may cause problems in waste liquid treatment. The biggest problem with the pyrometallurgical process is high energy consumption, and waste gases are easily generated at high temperatures. Moreover, no matter which process is used, it is difficult to simultaneously achieve the goal of separating metals such as iron and zinc in copper slag. Therefore, if a method can be developed that can separate and recover zinc and iron in copper slag efficiently with less energy consumption under medium - low temperature conditions, it is of great significance for promoting the efficient utilization of copper slag. Summary of the Invention

[0007] The present invention provides a method for separating, enriching iron and zinc by activated roasting of copper slag. For the first time, a grinding - leaching process is used to treat the calcine after the activated roasting of copper slag. By optimizing the dosages of dissociation agents and reducing agents, while reducing energy consumption, the zinc leaching rate in the grinding - leaching process is significantly increased, realizing the efficient separation of iron and zinc, that is, simultaneously improving the iron concentrate grade and fully recovering zinc.

[0008] The present invention provides a method for separating, enriching iron and zinc by activated roasting of copper slag, including: subjecting a mixture containing copper slag, reducing agent, and dissociation agent to activated roasting at 700 - 1000 °C to obtain calcine; mixing the calcine with an acid solution to obtain a pulp with a pH value of 2.5 - 4 and a mass concentration of 15 - 25%, and carrying out ball - milling leaching of the pulp under the condition of a ball - to - material ratio of 3 - 6:1, followed by solid - liquid separation to obtain an iron - containing filter residue and a zinc - containing filtrate; The dissociating agent includes sodium ions and carbonate ions; In the mixture, the mass ratio of copper slag to reducing agent is 100:5 to 15; In the mixture, the mass ratio of copper slag to dissociating agent is 100:3 to 15.

[0009] In order to achieve efficient separation of iron and zinc, the present invention adopts a grinding and leaching process to treat the calcined ore after the activation roasting of copper slag. Based on the synergistic effect of mechanical activation and solvent leaching, mechanical force is applied to the calcined ore by the grinding medium during the ball milling and leaching process, synchronously realizing the refinement of materials, the exposure of new surfaces, and the induction of lattice defects, promoting the contact reaction between the target metal phases (such as zinc oxide, etc.) and the leaching agent. At the same time, the local high temperature and shear force generated by ball milling further accelerate the interfacial mass transfer process, enabling the zinc oxide in the calcined ore to be efficiently dissolved in the leaching system, significantly increasing the zinc leaching rate. Meanwhile, during the activation roasting process, the dissociating agent is used to dissociate the mineral structure of fayalite, destroy the structure of the fayalite phase, release the copper, zinc and other minerals embedded therein, and improve the reaction activity of iron minerals, reducing the reaction temperature of roasting. Then, by systematically regulating the ratio of the carbonaceous reducing agent, a weak reducing atmosphere environment is provided during the reaction process, controlling the transformation of iron oxides into phases such as magnetite and elemental iron, realizing the efficient dissociation of the fayalite phase and the directional transformation of iron mineral phases. Compared with the traditional process, energy consumption is reduced. More importantly, it is found that optimizing the dosage of the dissociating agent and the reducing agent in the present invention further improves the zinc leaching rate in the grinding and leaching process and increases the activity of iron minerals. A higher zinc leaching rate is conducive to obtaining a high-concentration zinc-containing solution, thus facilitating the efficient and full recovery of zinc. The high activity of iron minerals helps to improve the magnetism of iron minerals, and the iron minerals mainly composed of magnetite will not dissolve into the solution, thereby realizing the efficient separation of iron and zinc and improving the grade of iron concentrate. Compared with the traditional method of treating copper slag by carbothermal reduction treatment process, the present invention avoids high content of zinc in iron concentrate. In other words, the present invention realizes the efficient separation of iron and zinc, and actually realizes the high-value recovery of iron and the full recovery of zinc at the same time.

[0010] According to the method for separating, enriching iron and zinc by activating and roasting copper slag provided by the present invention, the reducing agent is a carbonaceous reducing agent; the carbon-based reducing agent is selected from one or a combination of at least two of coke, charcoal, petroleum coke and anthracite, and preferably anthracite.

[0011] According to the method for separating, enriching iron and zinc by activating and roasting copper slag provided by the present invention, the dissociating agent is a combination of sodium salt and carbonate; preferably sodium carbonate.

[0012] According to the method for separating, enriching iron and zinc by activating and roasting copper slag provided by the present invention, the copper slag contains more than 30% iron and more than 1% zinc.

[0013] Preferably, the copper slag includes, but is not limited to, copper smelting slag produced by different smelting equipment and process systems, including any one or a combination of at least two of flash furnace slag, converter slag, electric furnace slag, vacuum furnace slag, and floating copper tailings.

[0014] According to the method for separating, enriching iron and zinc by activated roasting of copper slag provided by the present invention, the time for activated roasting is 1 - 4 h.

[0015] According to the method for separating, enriching iron and zinc by activated roasting of copper slag provided by the present invention, the ball - to - material ratio for ball milling and leaching is 5:1, and the leaching time is 1 - 3 h.

[0016] According to the method for separating, enriching iron and zinc by activated roasting of copper slag provided by the present invention, the acid solution is a sulfuric acid solution with a mass concentration of 5 - 15%.

[0017] According to the method for separating, enriching iron and zinc by activated roasting of copper slag provided by the present invention, the iron - containing filter residue is subjected to wet low - intensity magnetic separation to obtain high - grade iron concentrate and magnetic separation tailings; the magnetic field intensity for the wet low - intensity magnetic separation is 100 - 250 mT.

[0018] According to the method for separating, enriching iron and zinc by activated roasting of copper slag provided by the present invention, the grade of the iron concentrate is above 60%.

[0019] According to the method for separating, enriching iron and zinc by activated roasting of copper slag provided by the present invention, the zinc content in the zinc - containing filtrate is above 2.5 g / L.

[0020] The zinc - containing filtrate can be subjected to zinc powder replacement to obtain a zinc - containing solution, and the zinc - containing solution is electrolyzed to recover zinc.

[0021] Further preferably, the method for separating, enriching iron and zinc by activated roasting of copper slag includes the following steps: (a) Mix the copper slag, reducing agent, and dissociating agent by ball milling, and subject the obtained ball - milled material to activated roasting to obtain calcine; (b) Prepare a mixed pulp by mixing the obtained calcine with an acid solution, load it into a ball mill for ball milling and leaching, and after solid - liquid separation, obtain an iron - containing filter residue and a zinc - containing filtrate; During the ball milling and leaching process, the material of the ball milling medium includes, but is not limited to, agate, cemented carbide, zirconia ceramics, etc., the size of the ball milling medium is 5 - 50 mm, and the temperature for ball milling and leaching is below 95 °C.

[0022] (c) Subject the iron - containing filter residue to wet low - intensity magnetic separation to obtain iron concentrate and magnetic separation tailings.

[0023] By using the method of the present invention, an iron recovery rate of above 60% and a zinc recovery rate of above 85% can be achieved.

[0024] A method for separating, enriching iron and zinc by activating and roasting copper slag provided by the present invention adopts a grinding and leaching process to treat the roasted ore after activating and roasting copper slag, and by optimizing the dosages of dissociating agents and reducing agents, etc., while reducing energy consumption, the zinc leaching rate in the grinding and leaching process is significantly increased, realizing the efficient separation of iron and zinc, that is, simultaneously improving the grade of iron concentrate and fully recovering zinc, effectively solving the technical problems such as difficult separation of metals such as iron and zinc, high process temperature, and high energy consumption in the existing copper slag recovery process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a simplified process flow diagram of the method for separating, enriching iron and zinc by activating and roasting copper slag in Embodiment 1 provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0028] The following will describe Figure 1 a method for separating, enriching iron and zinc by activating and roasting copper slag of the present invention.

[0029] For those not specifying specific technologies or conditions in the embodiments, they shall be carried out according to the technologies or conditions described in the literature in the field or according to the product specifications. For reagents or instruments not specifying the manufacturer, they are all conventional products that can be obtained through regular channels.

[0030] Embodiment 1 This embodiment provides a method for separating, enriching iron and zinc by activating and roasting copper slag, as Figure 1 shown, including the following steps: (a) Mixing converter copper slag, a reducing agent, and a composite dissociating agent evenly through ball milling to obtain ball-milled material. The iron content in the converter copper slag is 42.51%, the zinc content is 1.92%, the reducing agent is anthracite, and the addition amount is 5% of the mass of the copper slag. The composite dissociating agent is sodium carbonate, and the sodium content is 3% of the mass of the copper slag. The obtained ball-milled material is subjected to activating roasting at 700 °C for 1 h to obtain roasted ore.

[0031] (b) The obtained calcine is formulated with a 5% concentration sulfuric acid solution into a mixed pulp and loaded into a ball mill for ball milling. The ball mill contains ball milling media made of agate with a diameter of 5 mm. The pulp concentration is controlled at 15%, the ball-to-material ratio is 5:1, the pH is controlled at 4, the ball milling temperature is 60 °C, the leaching time is 3 h. After ball milling, solid-liquid separation is carried out to obtain iron-rich filter residue and zinc-containing filtrate.

[0032] (c) The obtained iron-rich filter residue is subjected to wet low-intensity magnetic separation with the magnetic field intensity controlled at 100 mT to obtain high-grade iron concentrate and magnetic separation tailings. The grade of the obtained iron concentrate is analyzed to be 61.26%.

[0033] Through the analysis of the obtained zinc-containing filtrate, the zinc content in the solution is 2.5 g / L. Subsequently, zinc is recovered through further treatment to achieve the efficient separation and enrichment of iron and zinc from copper slag.

[0034] Example 2 This example provides a method for the activation roasting separation and enrichment of iron and zinc from copper slag, including the following steps: (a) The flash smelting copper slag, reducing agent, and composite dissociation agent are ball milled and mixed evenly to obtain ball milled material. The iron content in the flash smelting copper slag is 43.72% and the zinc content is 2.18%. The reducing agent is anthracite with an addition amount of 15% of the mass of the copper slag. The composite dissociation agent is sodium carbonate with the sodium content being 15% of the mass of the copper slag. The obtained ball milled material is subjected to activation roasting at 1000 °C for 4 h to obtain calcine.

[0035] (b) The obtained calcine is formulated with a 15% concentration sulfuric acid solution into a mixed pulp and loaded into a ball mill for ball milling. The ball mill contains ball milling media made of titanium alloy with a diameter of 10 mm. The pulp concentration is controlled at 25%, the ball-to-material ratio is 5:1, the pH is controlled at 2.5, the ball milling temperature is 95 °C, the leaching time is 1 h. After ball milling, solid-liquid separation is carried out to obtain iron-rich filter residue and zinc-containing filtrate.

[0036] (c) The obtained iron-rich filter residue is subjected to wet low-intensity magnetic separation with the magnetic field intensity controlled at 250 mT to obtain high-grade iron concentrate and magnetic separation tailings. The grade of the obtained iron concentrate is analyzed to be 81.30%. Through the analysis of the obtained zinc-containing filtrate, the zinc content in the solution is 4.5 g / L. Subsequently, zinc is recovered through further treatment to achieve the efficient separation and enrichment of iron and zinc from copper slag.

[0037] Example 3 This example provides a method for the activation roasting separation and enrichment of iron and zinc from copper slag, including the following steps: (a) The electric furnace copper slag, reducing agent, and composite dissociation agent are ball-milled and mixed evenly to obtain ball-milled material. The iron content in the electric furnace copper slag is 39.35% and the zinc content is 2.13%. The reducing agent is anthracite, and the addition amount is 10% of the mass of the copper slag. The composite dissociation agent is sodium carbonate, and the sodium content is 10% of the mass of the copper slag. The obtained ball-milled material is subjected to activation roasting at 800 °C for 2 h to obtain calcine.

[0038] (b) The obtained calcine is formulated with 10% concentrated sulfuric acid solution into a mixed pulp and loaded into a ball mill for ball milling. The ball mill contains zirconia material and ball milling media with a diameter of 50 mm. The pulp concentration is controlled at 20%, the ball-to-material ratio is 5:1, the pH is controlled at 3.5, the ball milling temperature is 60 °C, and the leaching time is 2 h. After ball milling, solid-liquid separation is carried out to obtain iron-rich filter residue and zinc-containing filtrate.

[0039] (c) The obtained iron-rich filter residue is subjected to wet low-intensity magnetic separation, and the magnetic field intensity is controlled at 200 mT to obtain high-grade iron concentrate and magnetic separation tailings. The grade of the obtained iron concentrate is analyzed to be 74.52%. By analyzing the obtained zinc-containing filtrate, the zinc content in the solution is 3.78 g / L. Subsequently, zinc is recovered through further treatment, realizing the efficient separation and enrichment of iron and zinc from copper slag.

[0040] Example 4 This example provides a method for separating and enriching iron and zinc by activation roasting of copper slag, including the following steps: (a) The tailings after floating copper, reducing agent, and composite dissociation agent are ball-milled and mixed evenly to obtain ball-milled material. The iron content in the tailings after floating copper is 41.34% and the zinc content is 1.87%. The reducing agent is anthracite, and the addition amount is 10% of the mass of the copper slag. The composite dissociation agent is sodium carbonate, and the sodium content is 10% of the mass of the copper slag. The obtained ball-milled material is subjected to activation roasting at 900 °C for 2 h to obtain calcine.

[0041] (b) The obtained calcine is formulated with 10% concentrated sulfuric acid solution into a mixed pulp and loaded into a ball mill for ball milling. The ball mill contains zirconia material and ball milling media with a diameter of 30 mm. The pulp concentration is controlled at 20%, the ball-to-material ratio is 5:1, the pH is controlled at 3.0, the ball milling temperature is 90 °C, and the leaching time is 2 h. After ball milling, solid-liquid separation is carried out to obtain iron-rich filter residue and zinc-containing filtrate.

[0042] (c) The obtained iron-rich filter residue is subjected to wet low-intensity magnetic separation, and the magnetic field intensity is controlled at 150 mT to obtain high-grade iron concentrate and magnetic separation tailings. The grade of the obtained iron concentrate is analyzed to be 65.45%. By analyzing the obtained zinc-containing filtrate, the zinc content in the solution is 3.7 g / L. Subsequently, zinc is recovered through further treatment, realizing the efficient separation and enrichment of iron and zinc from copper slag.

[0043] Example 5 This embodiment provides a method for separating, enriching iron and zinc by activated roasting of copper slag, which includes the following steps: (a) Vacuum smelted copper slag, a reducing agent, and a composite dissociation agent are evenly mixed by ball milling to obtain ball-milled material. The iron content in the copper slag is 38.52% and the zinc content is 1.78%. The reducing agent is anthracite, and the addition amount is 5% of the mass of the copper slag. The composite dissociation agent is sodium carbonate, and the sodium content is 15% of the mass of the copper slag. The obtained ball-milled material is subjected to activated roasting at 850 °C for 1 h to obtain calcine.

[0044] (b) The obtained calcine and a 5% concentration sulfuric acid solution are formulated into a mixed pulp and loaded into a ball mill for ball milling. The ball mill contains ball milling media made of agate with a diameter of 40 mm. The pulp concentration is controlled at 25%, the ball-to-material ratio is 5:1, the pH is controlled at 3.0, the ball milling temperature is 80 °C, and the leaching time is 3 h. After ball milling, solid-liquid separation is carried out to obtain iron-rich filter residue and zinc-containing filtrate.

[0045] (c) The obtained iron-rich filter residue is subjected to wet low-intensity magnetic separation, and the magnetic field intensity is controlled at 200 mT to obtain high-grade iron concentrate and magnetic separation tailings. The grade of the obtained iron concentrate is analyzed to be 72.91%.

[0046] Through analysis of the obtained zinc-containing filtrate, the zinc content in the solution is 3.12 g / L. Subsequently, zinc is recovered through further treatment, realizing the efficient separation and enrichment of iron and zinc from copper slag.

[0047] Comparative Example 1 This comparative example provides a method for separating, enriching iron and zinc by activated roasting of copper slag, which includes the following steps: (a) The same batch of vacuum smelted copper slag as in Example 5, with an iron content of 38.52% and a zinc content of 1.78%, is mixed and ball milled with anthracite and sodium carbonate. The dosage of anthracite is calculated according to the carbon-oxygen reduction ratio of 1.3, corresponding to 18% of the mass of the copper slag, and the addition amount of sodium carbonate is 15% of the mass of the copper slag. The obtained ball-milled material is subjected to activated roasting at 850 °C for 1 h to obtain calcine.

[0048] (b) The obtained calcine and a 5% concentration sulfuric acid solution are formulated into a mixed pulp and loaded into a ball mill for ball milling. The ball mill contains ball milling media made of agate with a diameter of 40 mm. The pulp concentration is controlled at 25%, the ball-to-material ratio is 5:1, the pH is controlled at 3.0, the ball milling temperature is 80 °C, and the leaching time is 3 h. After ball milling, solid-liquid separation is carried out to obtain iron-rich filter residue and zinc-containing filtrate.

[0049] (c) The obtained iron-rich filter residue is subjected to wet low-intensity magnetic separation, and the magnetic field intensity is controlled at 200 mT to obtain high-grade iron concentrate and magnetic separation tailings. The grade of the obtained iron concentrate is analyzed to be 51.23%. Through analysis of the obtained zinc-containing filtrate, the zinc content in the solution is 1.93 g / L.

[0050] Analysis of the above results shows that: a high carbon-oxygen ratio (1.3) leads to the over-reduction of some FeO to metallic iron, resulting in more iron being leached into the solution during the grinding and leaching process. The grade of the magnetic separation iron concentrate is only 51.23%, significantly lower than 72.91% in Example 5. Moreover, the increased dosage of the reducing agent increases fuel consumption, and the unreacted carbon remains in the slag, affecting the leaching effect. The zinc leaching rate is only about 75%, while the zinc leaching rate in Example 5 reaches over 95%, and the carbon consumption is reduced by over 60%.

[0051] Comparative Example 2 This comparative example provides a method for activating roasting, separating, and enriching iron and zinc from copper slag, including the following steps: a) Vacuum smelting copper slag from the same batch as in Example 5, with an iron content of 38.52% and a zinc content of 1.78%, is mixed and ball-milled with anthracite and sodium carbonate. The dosage of anthracite is 5%, and the dosage of sodium carbonate is 45% of the mass of the copper slag. The obtained ball-milled material is subjected to activating roasting at 850 °C for 1 h to obtain roasted ore.

[0052] b) The obtained roasted ore is formulated into a mixed pulp with a 5% concentration sulfuric acid solution and loaded into a ball mill for ball milling. The ball mill contains ball milling media made of agate with a diameter of 40 mm. The pulp concentration is controlled at 25%, the ball-to-material ratio is 5:1, the pH is controlled at 3.0, the ball milling temperature is 80 °C, and the leaching time is 3 h. After ball milling, solid-liquid separation is carried out to obtain iron-rich filter residue and zinc-containing filtrate. By analyzing the obtained zinc-containing filtrate, the zinc content in the solution is 2.14 g / L.

[0053] c) The obtained iron-rich filter residue is subjected to wet low-intensity magnetic separation, and the magnetic field intensity is controlled at 200 mT to obtain high-grade iron concentrate and magnetic separation tailings. The grade of the analyzed iron concentrate is 53.76%.

[0054] Analysis of the above results shows that: excessive sodium carbonate generates a high-viscosity Na2SiO3 glass phase during roasting, the furnace charge sinters into blocks, and there are still undissociated particles after ball milling, resulting in a decrease in the zinc leaching rate during the ball milling and leaching process and a decrease in the iron grade during the magnetic separation process. At the same time, the residual sodium salt raises the initial pH of the leaching solution to 4.5, and additional sulfuric acid needs to be added to adjust it to 3.0, increasing the sulfuric acid consumption by 30%.

[0055] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for separating and enriching iron and zinc by activated roasting of copper slag, characterized in that, Comprising: Performing activation roasting on a mixture containing copper slag, a reducing agent, and a dissociating agent at 700 - 1000 °C to obtain roasted ore; mixing the roasted ore with an acid solution to obtain a pulp with a pH value of 2.5 - 4 and a mass concentration of 15 - 25%, and performing ball milling leaching on the pulp under the condition that the ball-to-material ratio is 3 - 6:1, followed by solid-liquid separation to obtain iron-containing filter residue and zinc-containing filtrate; The dissociating agent comprises sodium ions and carbonate ions; The mass ratio of copper slag to the reducing agent in the mixture is 100:5 - 15; The mass ratio of copper slag to the dissociating agent in the mixture is 100:3 - 15.

2. The method for separating, enriching iron and zinc by activating and roasting copper slag according to claim 1, wherein The reducing agent is a carbonaceous reducing agent; the carbon-based reducing agent is selected from one or a combination of at least two of coke, charcoal, petroleum coke, and anthracite, preferably anthracite.

3. The method for separating, enriching iron and zinc by activating and roasting copper slag according to claim 1 or 2, characterized in that, The dissociating agent is a combination of a sodium salt and a carbonate; preferably sodium carbonate.

4. A method for activating roasting and separating and enriching iron and zinc from copper slag according to any one of claims 1 to 3, characterized in that, The iron content in the copper slag is more than 30%, and the zinc content is more than 1%.

5. A method for activating roasting and separating and enriching iron and zinc from copper slag according to any one of claims 1 to 4, characterized in that, The time for the activation roasting is 1 - 4 h.

6. A method for separating and enriching iron and zinc by activating and roasting copper slag according to any one of claims 1 to 5, characterized in that, The ball-to-material ratio for the ball milling leaching is 5:1, and the leaching time is 1 - 3 h.

7. A method for separating and enriching iron and zinc by activating and roasting copper slag according to any one of claims 1 to 6, characterized in that, The acid solution is a sulfuric acid solution with a mass concentration of 5 - 15%.

8. The method for activating and roasting copper slag to separate and enrich iron and zinc according to any one of claims 1 to 7, characterized in that, Performing wet low-intensity magnetic separation on the iron-containing filter residue to obtain high-grade iron concentrate and magnetic separation tailings; the magnetic field intensity for the wet low-intensity magnetic separation is 100 - 250 mT.

9. A method for activating and roasting copper slag to separate and enrich iron and zinc according to any one of claims 1 to 8, characterized in that, The grade of the iron concentrate is more than 60%.

10. The method for separating and enriching iron and zinc by copper slag activation roasting according to any one of claims 1 to 9, characterized in that, The zinc content in the zinc-containing filtrate is more than 2.5 g / L.

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