High-added-value collaborative utilization method of copper slag

Abstract

The invention belongs to the cross technical field of environment and metallurgical engineering, and particularly relates to a method for high-added-value collaborative utilization of copper slag. According to the method, copper slag alkali dissolution leaching cooperates with flue gas carbon capture and sulfur resource recovery, firstly, iron and silicon separation is conducted on the copper slag through alkali dissolution leaching, then silicon resources are recovered from the copper slag through flue gas carbon capture, valuable element recovery is achieved, the high-added-value product white carbon black is prepared, the obtained white carbon black can serve as an industrial catalyst carrier, CO2 is captured at the same time, and the sulfur recovery rate is increased. The ecological balance is facilitated; in addition, by means of the efficient catalytic property of the iron-containing copper slag, the iron-containing copper slag serves as a catalyst to be used for sulfur-containing flue gas treatment, and sulfur resource recovery is achieved. According to the method, residual elements in the copper slag are completely recycled, and high-added-value cooperative utilization of the copper slag is achieved. The method provided by the invention is simple, efficient, green and environment-friendly, green circulation of treating waste with waste is realized, and CO2-containing flue gas and H2S-containing flue gas are treated while resource utilization of the copper slag is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of intersection of environment and metallurgical engineering, and particularly relates to a method for high value-added coordinated utilization of copper slag. Background Art

[0002] Copper slag is a solid waste generated during the copper smelting process, mainly formed by quenching molten slag with water or naturally cooling. The traditional treatment method of copper slag is mainly storage or landfill, which not only occupies land resources, but also poses a threat to the ecological environment due to the risk of heavy metal leaching. At the same time, copper slag is rich in silicon resources. The silicon content in copper slag is generally 25-35%, but its occurrence form is mainly fayalite (Fe2SiO4) and amorphous silicon dioxide (SiO2). The silicon element is wrapped in glass, with fine embedded particles and uniform dispersion, making it impossible for traditional mineral processing methods to effectively separate iron and silicon elements.

[0003] Currently, there are three main methods for recovering silicon from copper slag: carbon thermal reduction-alkaline leaching, high-temperature oxidative roasting-alkaline leaching, wet acid leaching, and melt separation to recover silicon resources; pyrometallurgical reduction or oxidation methods to separate iron and silicon at high temperatures; and wet acid leaching, which uses pressurized strong acid to recover silicon from copper slag. However, these processes either generate secondary pollution or have low product value.

[0004] Therefore, how to obtain high value-added products without generating secondary pollution is a problem faced by the resource utilization of copper slag. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for high-value-added collaborative utilization of copper slag. The method provided by the present invention is green and environmentally friendly, and realizes high-value-added collaborative utilization of copper slag.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for high value-added collaborative utilization of copper slag, comprising the following steps:

[0008] mixing copper slag, alkali and water to carry out alkali leaching reaction to obtain alkali leached copper slag and silicate-containing solution;

[0009] The alkaline-leached copper slag and hydrogen peroxide are slurried, and the obtained copper slag slurry catalytically oxidizes the H2S-containing flue gas to obtain sulfur;

[0010] Flue gas containing CO2 is introduced into the silicate-containing solution to carry out a precipitation reaction to obtain white carbon black.

[0011] Preferably, the flow rate of the CO2-containing flue gas is 0.1-0.5 L / min; the volume fraction of CO2 in the CO2-containing flue gas is 0.05-2%; and the concentration of silicon in the silicate solution is 1-10 g / L.

[0012] Preferably, the precipitation reaction temperature is 25-65° C., and the insulation time is 0.5-3 h.

[0013] Preferably, the H2S-containing flue gas is introduced into the copper slag slurry for catalytic oxidation, and the introduction flow rate of the H2S-containing flue gas is 0.1-1.0 L / min; the H2S concentration of the H2S-containing flue gas is 300-1800 mg / m 3 .

[0014] Preferably, the temperature of the catalytic oxidation is 25 to 55° C., and the time of the catalytic oxidation is 6 to 12 hours.

[0015] Preferably, the catalytic oxidation further comprises magnetic separation of the obtained product; the magnetic field intensity of the magnetic separation is 0.10 to 0.18T.

[0016] Preferably, the slurrying comprises the following steps: mixing the alkali-leached copper slag with hydrogen peroxide and water to obtain a copper slag slurry.

[0017] Preferably, the solid-liquid mass ratio of the copper slag slurry is 1:5-100, and the concentration of hydrogen peroxide is 0.1-2.0 mol / L.

[0018] Preferably, the particle size of the copper slag is 38 to 270 μm; the mass ratio of the alkali to the copper slag is 1 to 2.5:1; and the mass ratio of the water to the copper slag is 1 to 5:1.

[0019] Preferably, the temperature of the alkaline leaching reaction is 50-130° C., and the insulation time is 0.5-4 h.

[0020] The present invention provides a method for high value-added synergistic utilization of copper slag. The present invention combines alkaline leaching of copper slag with flue gas carbon capture and sulfur resource recovery. First, the copper slag is separated from iron and silicon by alkaline leaching, and then silicon resources are recovered from the copper slag by flue gas carbon capture, thereby realizing the recovery of valuable elements and producing high value-added product white carbon black. The obtained white carbon black can be used as an industrial catalyst carrier and captures CO2 at the same time, which is beneficial to ecological balance. In addition, by utilizing the efficient catalytic properties of the iron-containing copper slag, it is used as a catalyst for sulfur-containing flue gas treatment to realize sulfur resource recovery. The present invention completely recycles the residual elements in the copper slag and realizes high value-added synergistic utilization of the copper slag. The method provided by the present invention is simple, efficient, green and environmentally friendly, realizing a green cycle of "waste treatment with waste", and realizing the treatment of flue gas containing CO2 and H2S while utilizing the copper slag as a resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a process flow chart of the method for high value-added collaborative utilization of copper slag according to the present invention;

[0023] Figure 2 is the XRD pattern of the original copper slag of the present invention;

[0024] Figure 3 is the XRD pattern of the alkali-leached copper slag of the present invention;

[0025] Figure 4 This is a performance diagram of removing hydrogen sulfide from alkaline leached copper slag according to an embodiment of the present invention;

[0026] Figure 5 This is the XRD pattern of white carbon black obtained in the embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention provides a method for high value-added collaborative utilization of copper slag, comprising the following steps:

[0028] mixing copper slag, alkali and water to carry out alkali leaching reaction to obtain alkali leached copper slag and silicate-containing solution;

[0029] The alkaline-leached copper slag and hydrogen peroxide are slurried, and the obtained copper slag slurry catalytically oxidizes the H2S-containing flue gas to obtain sulfur;

[0030] Flue gas containing CO2 is introduced into the silicate-containing solution to carry out a precipitation reaction to obtain white carbon black.

[0031] Figure 1 The process flow chart of the method for high value-added synergistic utilization of copper slag of the present invention is shown. The present invention mixes copper slag, alkali, and water to perform an alkaline leaching reaction to obtain alkaline-leached copper slag and a silicate-containing solution. In the present invention, the particle size of the copper slag can be 38 to 270 μm, specifically 50 μm, 74 μm, 100 μm, 120 μm, 150 μm, 170 μm, 200 μm, or 240 μm. The use of copper slag of the above-mentioned particle size in the present invention can make the copper slag dissociate more fully and more easily react with alkaline substances.

[0032] In the present invention, the copper slag can be obtained by sequentially crushing, grinding and screening the original copper slag.

[0033] In the present invention, the alkali may be one or both of sodium hydroxide and potassium hydroxide.

[0034] In the present invention, the mass ratio of the alkali to the copper slag can be 1 to 2.5:1, specifically 1.5:1 or 2:1. The present invention uses the above amount of alkali to fully dissociate fayalite without wasting alkali solution.

[0035] In the present invention, the mass ratio of water to copper slag may be 1 to 5:1, specifically 2:1, 3:1 or 4:1.

[0036] In the present invention, the temperature of the alkali leaching reaction can be 50 to 130°C, specifically 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, and the holding time can be 0.5 to 4 hours, specifically 1 hour, 2 hours or 3 hours. The alkali leaching under the above conditions of the present invention can increase the activation energy of the alkali and fayalite, thereby increasing the decomposition rate of fayalite, which is conducive to the full reaction of fayalite with the alkali.

[0037] The original copper slag has a poor effect on removing H2S flue gas. The present invention can effectively improve the removal efficiency and removal time of H2S by subjecting the original copper slag to alkaline leaching. The present invention found in research that this is because alkaline leaching can effectively increase the content of magnetite mineral phase and reduce silicon-containing phases. The silicon-containing phase is rich in silicon dioxide, and silicon dioxide has no effect on H2O2 excitation. In addition, the present invention found in research that the original copper slag / H2O2 system cannot generate free radicals in a directionally generated manner, and thus cannot generate sulfur in a directionally generated manner. The present invention causes the copper slag to undergo a phase transformation through alkaline leaching, realizes the directional regulation of free radicals, and thus realizes the regulation of products. Therefore, the present invention is able to achieve efficient and long-lasting removal of H2S and directional generation of sulfur.

[0038] In the present invention, the alkaline leaching reaction may be followed by solid-liquid separation of the obtained product; the solid-liquid separation may be performed by filtration.

[0039] After obtaining the alkali-leached copper slag, the present invention prepares a slurry by mixing the alkali-leached copper slag with hydrogen peroxide. The resulting copper slag slurry catalytically oxidizes H2S-containing flue gas to produce sulfur. In the present invention, the slurrying may include the following steps: mixing the alkali-leached copper slag with hydrogen peroxide and water to obtain a copper slag slurry.

[0040] In the present invention, the solid-liquid mass ratio of the copper slag slurry can be 1:5 to 100, specifically 1:10, 1:15, 1:20, 1:30, 1:50, 1:70, or 1:90, and the concentration of hydrogen peroxide can be 0.1 to 2.0 mol / L, specifically 0.5 mol / L, 1.0 mol / L, or 1.5 mol / L. The present invention forms an alkaline-leached copper slag / H2O2 advanced oxidation system by adding the above-mentioned amount of hydrogen peroxide. The resulting oxygen-containing free radicals can catalytically oxidize H2S, thereby efficiently removing H2S.

[0041] In the present invention, the H2S-containing flue gas can be introduced into the copper slag slurry for catalytic oxidation. The flow rate of the H2S-containing flue gas can be 0.1 to 1.0 L / min, specifically 0.3 L / min, 0.5 L / min, 0.7 L / min or 0.9 L / min; the H2S concentration of the H2S-containing flue gas can be 300 to 1800 mg / m 3 , specifically 500mg / m 3 , 700mg / m 3 , 1000mg / m 3 , 1200mg / m 3 or 1500 mg / m 3 The present invention adopts the above concentration to improve the mass transfer efficiency and thus enhance the removal of H2S; the present invention adopts the above flow rate to ensure that the residence time of H2S in the liquid phase is sufficient, thereby fully promoting the subsequent catalytic oxidation reaction and improving the H2S removal efficiency.

[0042] In the present invention, the catalytic oxidation temperature can be 25 to 55° C., specifically 35° C. or 45° C., and the catalytic oxidation time can be 6 to 12 hours, specifically 8 hours or 10 hours. The catalytic oxidation under the above conditions is beneficial for reducing the activation energy of hydrogen peroxide decomposition, thereby increasing the rate of free radical generation, while avoiding the occurrence of hydrogen peroxide side reactions and ensuring full utilization of hydrogen peroxide.

[0043] In the present invention, the catalytic oxidation may be followed by magnetic separation of the resulting product; the magnetic field strength of the magnetic separation may be 0.10 to 0.18 T, specifically 0.13 T or 0.15 T. The magnetic separation at the aforementioned magnetic field strength can effectively separate elemental sulfur from magnetite (the main component of alkaline leached copper slag) to obtain sulfur and magnetite.

[0044] After obtaining the silicate-containing solution, the present invention introduces CO2-containing flue gas into the silicate-containing solution for precipitation reaction to obtain white carbon black. In the present invention, the volume fraction of CO2 in the CO2-containing flue gas can be 0.05-2%, specifically 0.1%, 0.3%, 0.5%, 0.7%, 1%, 1.2%, 1.5%, or 1.8%.

[0045] In the present invention, the concentration of silicon in the silicate-containing solution may be 1 to 10 g / L, specifically 3 g / L, 5 g / L or 8 g / L.

[0046] In the present invention, the flow rate of the CO2-containing flue gas can be 0.1 to 0.5 L / min, specifically 0.2 L / min, 0.3 L / min, or 0.4 L / min. The present invention utilizes the above concentration and flow rate to effectively and fully absorb CO2 and react with sodium silicate to form white carbon black.

[0047] In the present invention, the precipitation reaction temperature can be 25-65°C, specifically 35°C, 45°C, or 55°C, and the holding time can be 0.5-3 hours, specifically 1 hour, 1.5 hours, 2 hours, or 2.5 hours. The precipitate obtained in the system through the precipitation reaction is white carbon black. The above reaction conditions ensure a good CO2 absorption effect and prevent a decrease in CO2 solubility.

[0048] In the present invention, the precipitation reaction may further include solid-liquid separation and drying of the obtained product; the solid-liquid separation may be filtration; the drying temperature may be 105° C., and the insulation time may be 8 to 24 hours, specifically 12 hours, 16 hours or 20 hours.

[0049] In order to further illustrate the present invention, the scheme of the present invention is described in detail below with reference to the accompanying drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] The original copper slag is crushed and ground, and passed through a 74μm aperture sieve to obtain copper slag, which is then mixed with an aqueous NaOH solution for alkaline leaching reaction, wherein the mass ratio of sodium hydroxide to copper slag is 1:1, the mass ratio of water to copper slag is 1:1, the temperature of the alkaline leaching reaction is 90°C, and the insulation time is 2h. The product solution obtained by the alkaline leaching reaction is filtered to obtain alkaline-leached copper slag and sodium silicate solution, respectively. The alkaline-leached copper slag is then mixed with hydrogen peroxide (concentration 30wt%) and deionized water for pulping to obtain a copper slag slurry, wherein the solid-liquid mass ratio of the copper slag slurry is 1:20 and the hydrogen peroxide content is 1.0mol / L. Simulated yellow phosphorus tail gas (containing H2S flue gas) is then introduced into the copper slag slurry, and the H2S concentration in the yellow phosphorus tail gas is 1800mg / m 3The catalytic oxidation was carried out at a reaction temperature of 45°C. After 12 hours of reaction, magnetic separation was performed at a magnetic field strength of 0.18 T to obtain sulfur. CO2 gas (including CO2 flue gas) with a volume concentration of 1.0% was directly introduced into the sodium silicate solution at a gas flow rate of 0.1 L / min. After absorption saturation, it was filtered and dried at 105°C for 8 hours to obtain white carbon black.

[0052] Example 2

[0053] The original copper slag is crushed and ground, and passed through a 74μm aperture sieve to obtain copper slag, which is then mixed with an aqueous NaOH solution for alkaline leaching reaction, wherein the mass ratio of sodium hydroxide to copper slag is 1.5:1, the mass ratio of water to copper slag is 2:1, the temperature of the alkaline leaching reaction is 110°C, and the holding time is 2h. The product solution obtained by the alkaline leaching reaction is filtered to obtain alkaline-leached copper slag and sodium silicate solution, respectively. The alkaline-leached copper slag is then mixed with hydrogen peroxide (concentration 30wt%) and deionized water for pulping to obtain a copper slag slurry, wherein the solid-liquid mass ratio of the copper slag slurry is 1:40 and the hydrogen peroxide content is 0.3mol / L. Simulated yellow phosphorus tail gas is then introduced into the copper slag slurry, and the H2S concentration in the yellow phosphorus tail gas is 1800mg / m 3 The catalytic oxidation was carried out at a reaction temperature of 45°C. After 6 hours of reaction, magnetic separation was performed at a magnetic field strength of 0.10 T to obtain sulfur. CO2 gas with a volume concentration of 1.0% was directly introduced into the sodium silicate solution at a gas flow rate of 0.1 L / min. After absorption saturation, it was filtered and dried at 105°C for 24 hours to obtain white carbon black.

[0054] Test Example 1

[0055] The original copper slag and the prepared alkaline leached copper slag were subjected to XRD analysis, and the results were as follows: Figure 2 and Figure 3 shown.

[0056] according to Figure 2 It can be seen that the iron phase in the original copper slag mainly exists in the form of fayalite (Fe2SiO4) and magnetite (Fe3O4).

[0057] according to Figure 3 It can be seen that after alkaline leaching treatment, the fayalite in the alkaline leached copper slag is effectively decomposed and dissociated into Fe3O4 and SiO2, while the silicon dioxide further reacts with the sodium hydroxide solution and dissolves in the liquid phase of the solution.

[0058] Test Example 2

[0059] The alkali-leached copper slag prepared in Example 1 was tested for its hydrogen sulfide removal performance. The test method was as follows: 10 g of alkali-leached copper slag was first added to the reactor, followed by 180 mL of water and 200 mL of 30 wt% hydrogen peroxide. The reactor was then placed in a 45°C water bath for preheating for 10 minutes. After the preheating was completed, 1800 mg / m 3 The H2S simulated flue gas was reacted, and the results were as follows Figure 4 shown.

[0060] according to Figure 4 It can be seen that after 180 minutes, the hydrogen sulfide removal rate reaches more than 20%, about 25%. It can be seen that the alkaline leached copper slag prepared in the embodiment has a good effect on removing hydrogen sulfide.

[0061] Test Example 3

[0062] The white carbon black prepared in Example 1 was subjected to XRD analysis, and the results were as follows: Figure 5 As shown. Figure 5 It can be seen that there is no diffraction peak of crystalline silica in the XRD pattern. On the contrary, a steamed bun peak appears at around 24°, proving the formation of amorphous silica.

[0063] As can be seen from the above examples, the method provided by the present invention achieves high-value-added synergistic utilization of copper slag. It is simple, efficient, and environmentally friendly, achieving a green cycle of "waste treatment with waste," while simultaneously utilizing copper slag as a resource and treating CO2- and H2S-containing flue gases.

[0064] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for high value-added collaborative utilization of copper slag, characterized in that: The following steps are involved: mixing copper slag, alkali and water to carry out alkali leaching reaction to obtain alkali leached copper slag and silicate-containing solution; The alkaline-leached copper slag and hydrogen peroxide are slurried, and the obtained copper slag slurry catalytically oxidizes the H2S-containing flue gas to obtain sulfur; Flue gas containing CO2 is introduced into the silicate-containing solution to carry out a precipitation reaction to obtain white carbon black.

2. The method according to claim 1, characterized in that The flow rate of the CO2-containing flue gas is 0.1 to 0.5 L / min; The volume fraction of CO2 in the CO2-containing flue gas is 0.05-2%; The concentration of silicon in the silicate solution is 1 to 10 g / L.

3. The method according to claim 1 or 2, characterized in that The temperature of the precipitation reaction is 25-65° C., and the insulation time is 0.5-3 hours.

4. The method according to claim 1, wherein The H2S-containing flue gas is introduced into the copper slag slurry for catalytic oxidation, and the introduction rate of the H2S-containing flue gas is 0.1 to 1.0 L / min; The H2S concentration of the H2S-containing flue gas is 300-1800 mg / m 3 .

5. The method according to claim 1, characterized in that The temperature of the catalytic oxidation is 25 to 55° C., and the time of the catalytic oxidation is 6 to 12 hours.

6. The method according to claim 1 or 5, characterized in that After the catalytic oxidation, the obtained product is subjected to magnetic separation; the magnetic field intensity of the magnetic separation is 0.10-0.18T.

7. The method according to claim 1 or 4, characterized in that The slurrying process comprises the following steps: mixing the alkali-leached copper slag with hydrogen peroxide and water to obtain copper slag slurry.

8. The method according to claim 1 or 7, characterized in that The solid-liquid mass ratio of the copper slag slurry is 1:5-100, and the concentration of hydrogen peroxide is 0.1-2.0 mol / L.

9. The method according to claim 1, characterized in that The particle size of the copper slag is 38 to 270 μm; the mass ratio of the alkali to the copper slag is 1 to 2.5:1; and the mass ratio of the water to the copper slag is 1 to 5:

1.

10. The method according to claim 1 or 9, characterized in that The temperature of the alkaline leaching reaction is 50-130° C., and the insulation time is 0.5-4 hours.

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