An arsenic phase regulator, a preparation method thereof and application of the arsenic phase regulator in regulating separation of arsenic and valuable metals in smelting flue gas

Abstract

This application relates to an arsenic phase modifier, its preparation method, and its application in controlling the separation of arsenic from valuable metals in smelting flue gas, belonging to the field of clean production technology. The arsenic phase modifier is a compound or mixture having the chemical formula CuFe2S3. This invention also provides a method for obtaining CuFe2S3 by mixing chalcopyrite powder and sulfur powder and then activating the mixture through mechanical ball milling. After the arsenic phase modifier CuFe2S3 is mixed into the smelting flue gas, it consumes oxygen in the flue gas to inhibit arsenate formation and provides active sulfur components to enhance the conversion of metal oxides into sulfates. Arsenic volatilizes in the form of As2O3, thereby achieving the goal of separating arsenic from valuable metals.

Description

Technical Field

[0001] This invention relates to the field of clean production technology, and in particular to an arsenic phase modifier, its preparation method, and its application in controlling the separation of arsenic from valuable metals in smelting flue gas. Background Technology

[0002] Arsenic is often found in various non-ferrous metal minerals, and due to its volatility, it inevitably enters the smelting system during the smelting process. Arsenic in flue gas affects the catalytic conversion system of subsequent acid production sections; moreover, as a significant source of atmospheric arsenic pollutants, its effective purification is crucial for air pollution control and the green development of the smelting industry.

[0003] Dry quenching for arsenic recovery, due to its short process flow and high removal and recovery efficiency, can directly recover arsenic and has been adopted by smelting enterprises for arsenic removal from flue gas. Smelting flue gas temperatures are high, and arsenic in the flue gas competes with SO2 to react with metal oxides, forming corresponding arsenates or sulfates. However, the formed arsenates hinder the separation of arsenic from metal oxides, reducing the efficiency of dry arsenic recovery. Currently, most methods focus on the condensation and capture of gaseous arsenic. During flue gas condensation, components such as copper, lead, and zinc react with As2O3 to form arsenates, and the problem of separating arsenic from valuable metals remains unresolved. Chinese patent CN117160207A discloses a method using chalcopyrite powder as a regulator to inhibit arsenate formation and separate arsenic from valuable metals, but the arsenic separation rate in this method still needs improvement.

[0004] Therefore, it is necessary to design a new arsenic phase modifier to enhance the conversion of metal oxides to sulfates in flue gas through phase regulation, thereby inhibiting the formation of arsenate and achieving the separation of arsenic from valuable metals. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide an arsenic phase regulator and its preparation method. The arsenic phase regulator rich in active sulfur is prepared and used in smelting flue gas to regulate the phase transformation process of arsenic and metal oxide minerals, thereby inhibiting the formation of arsenates and achieving the separation of arsenic from valuable metals. After separation, the arsenic is captured in the form of As2O3 by existing dry arsenic collection equipment, while the metal is directly returned to the smelting system in the form of sulfates or oxides, which significantly reduces the generation of arsenic-containing heavy metal dust.

[0006] The present invention provides an arsenic phase modifier, wherein the modifier is a compound or mixture having the chemical formula CuFe2S3.

[0007] It should be noted that the "compound or mixture having the chemical formula CuFe2S3" mentioned in this invention can be a compound CuFe2S3 synthesized by means that are available to those skilled in the art, or it can be a mixture containing CuFe2S3, such as chalcopyrite.

[0008] The present invention also provides a method for preparing the above-mentioned arsenic phase modifier, which is prepared by mechanical ball milling using chalcopyrite and sulfur powder as raw materials, wherein the mass ratio of chalcopyrite to sulfur powder is 3:1 to 5:1.

[0009] Preferably, the ball-to-material ratio in the mechanical ball mill is 10:1 to 20:1.

[0010] Preferably, the ball milling time is 2 to 6 hours.

[0011] Preferably, the particle size of the regulator obtained by ball milling is <0.1 mm.

[0012] The present invention also provides a method for controlling the separation of arsenic and metal oxides in smelting flue gas, wherein the above-mentioned arsenic phase regulator is used as a regulator to inhibit the formation of arsenate, wherein the amount of the arsenic phase regulator is 40% to 60% of the total mass of arsenic and valuable metals.

[0013] It should be noted that the smelting flue gas involved in this invention can be regulated by the method described in this invention as long as it contains valuable metals and arsenic. For example, it can be copper smelting flue gas, lead smelting flue gas, zinc smelting flue gas, etc.

[0014] Preferably, the amount of arsenic phase modifier added is 50-60% of the total mass of arsenic and metal oxides.

[0015] Preferably, the reaction temperature is 600~700℃. The reaction temperature can be understood as the temperature at which the smelting flue gas reacts with the arsenic phase control agent. In actual production, the temperature of the directly emitted smelting flue gas is above 1000℃. After waste heat recovery, the temperature is adjusted to below 800℃, so that it can directly react with the arsenic phase control agent, thereby achieving arsenic phase control.

[0016] During the condensation of smelting flue gas, metal oxides react with SO2, O2, and As2O3 to form sulfates or arsenates, which coexist stably. Therefore, enhancing the conversion of metal oxides to sulfates is an effective way to inhibit the formation of arsenates. Furthermore, converting the formed arsenates into sulfates can also effectively release arsenic.

[0017] The key technology of this invention lies in utilizing the reaction of CuFe₂S₃ with metal oxides in flue gas under appropriate temperature conditions to regulate the phase transformation process of metal oxides and As₂O₃, thereby inhibiting arsenate formation. CuFe₂S₃, acting as an arsenic phase regulator, consumes oxygen in the system through oxidation and provides a sulfur source to enhance the conversion of metal oxides into sulfates or to dissociate the formed arsenates, thus achieving the goal of inhibiting arsenate formation. Arsenic will then enter the next process in gaseous As₂O₃ form. In a smelting atmosphere of 600–700°C, the inhibition of arsenate formation by CuFe₂S₃ mainly involves the following reactions:

[0018] ,

[0019] As can be seen from the above reaction, copper is mainly converted into stable metal sulfates, while iron is converted into oxides and sulfates, thereby inhibiting the formation of arsenates.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The arsenic phase regulator CuFe2S3 of this invention regulates the phase composition of arsenic and metal oxides in smelting flue gas, inhibits the formation of arsenates, and achieves the separation of arsenic from valuable metals in smelting flue gas. Combined with existing dry arsenic removal equipment, it can significantly improve the arsenic recovery rate and reduce the generation of arsenic-containing heavy metal dust. Attached Figure Description

[0022] Figure 1 The product mineral phases prepared under different ratios of chalcopyrite and sulfur powder in Example 1;

[0023] Figure 2 The mineral phases of the products prepared under different ball milling times and ball-to-material ratios in Examples 2 and 3;

[0024] Figure 3 This is a graph showing the separation effect of arsenic and valuable metals under different CuFe2S3 dosages in Example 4.

[0025] Figure 4 This is a graph showing the separation effect of arsenic and valuable metals at different temperatures in Example 5;

[0026] Figure 5 This is a graph showing the separation effect of arsenic and valuable metals under different O2 and SO2 concentrations in Example 6;

[0027] Figure 6 This is a comparison chart showing the effect of CuFe2S3 prepared in this invention on the separation of arsenic and valuable metals in flue gas under the same dosage, temperature and atmosphere. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings. It should be noted that the reagents, raw materials, instruments, and equipment involved in the present invention are all commercially available products.

[0029] Example 1: Chalcopyrite powder and sulfur powder were mixed at different mass ratios (1:0~5:1), and CuFe2S3 was prepared by mechanical ball milling for 6 hours at a ball-to-material ratio of 20:1. Figure 1 As shown, when the mass ratio of chalcopyrite powder to sulfur powder is less than 4:1, sulfur phase is present in addition to CuFe2S3. Therefore, it is advisable to control the mass ratio of chalcopyrite powder to sulfur powder at 4:1.

[0030] Example 2: CuFe2S3 was prepared by mechanically ball milling chalcopyrite powder and sulfur powder at a fixed mass ratio of 4:1 and a ball-to-material ratio of 20:1 for different times. Figure 2 As shown in Figure a, the residual S phase gradually disappears with increasing ball milling time. To obtain a relatively pure CuFe2S3 material, the mechanical ball milling time should be controlled at 6 hours.

[0031] Example 3: CuFe2S3 was prepared by fixing the mass ratio of chalcopyrite powder and sulfur powder at 4:1 and mechanically ball-milling for 6 hours under different ball-to-powder ratios. Figure 2 As shown in b, the residual S phase gradually disappears as the ball-to-material ratio increases. To obtain a relatively pure CuFe2S3 material, the ball-to-material ratio should be controlled at 20:1.

[0032] Example 4: CuFe2S3 prepared by mechanically ball milling chalcopyrite powder and sulfur powder at a mass ratio of 4:1 for 6 hours and a ball-to-material ratio of 20:1 was used to regulate the separation of arsenic from valuable metals in smelting flue gas. In this example, the mass ratio of CuO to As2O3 was 2:1, the gaseous components of the constant smelting flue gas were 20% O2, 25% SO2, 10% CO2, and 45% N2, the reaction was carried out at 600℃ for 60 minutes, and the reaction tail gas was discharged after two-stage washing. The separation rates of arsenic from valuable metals under different CuFe2S3 dosages (10%~60%) are as follows: Figure 3 As shown, with the increase of CuFe2S3 dosage, the separation rate of arsenic from valuable metals increased significantly, reaching a maximum of 95.61% at a dosage of 60%.

[0033] Example 5: CuFe2S3, prepared by mechanically ball milling chalcopyrite powder and sulfur powder at a mass ratio of 4:1 for 6 hours and a ball-to-material ratio of 20:1, was used to regulate the separation of arsenic from valuable metals in smelting flue gas. The regulation of arsenic separation by CuFe2S3 in smelting flue gas at different temperatures was studied. In this example, the mass ratio of CuO to As2O3 was 2:1, the CuFe2S3 dosage was 60%, and the gaseous components of the constant smelting flue gas were 20% O2, 25% SO2, 10% CO2, and 45% N2. The reaction was carried out at 600℃ for 60 minutes, and the reaction tail gas was discharged after two stages of washing. Figure 4 As shown, the separation rate of arsenic from valuable metals increases significantly with increasing temperature, reaching a maximum of 95.61% at 600℃. It decreases slightly at 700~800℃.

[0034] Example 6: CuFe2S3 prepared by mechanically ball milling chalcopyrite powder and sulfur powder at a mass ratio of 4:1 for 6 hours and a ball-to-material ratio of 20:1 was used to regulate the separation of arsenic from valuable metals in smelting flue gas. The regulation of arsenic separation by CuFe2S3 in different smelting flue gases was studied. In this example, the mass ratio of CuO to As2O3 was 2:1, the CuFe2S3 dosage was 60%, the reaction was carried out at 600℃ for 60 minutes, and the reaction tail gas was discharged after two-stage washing.

[0035] like Figure 5 As shown in Figure a, in a constant smelting flue gas with a gaseous composition of 25% SO2, 10% CO2, and N2 as the equilibrium gas, the separation rate of arsenic and valuable metals regulated by CuFe2S3 significantly decreases with increasing O2 concentration (0%~50%). Without O2, the separation rate of arsenic and valuable metals is 99.74%; at a 50% O2 concentration, the separation rate decreases to 86.71%.

[0036] like Figure 5 As shown in b, the gaseous components of the constant smelting flue gas are 20% O2, 10% CO2, and N2 as the equilibrium gas. The separation rate of arsenic and valuable metals, regulated by CuFe2S3, increases with increasing SO2 concentration (0%~55%). Without SO2, the separation rate of arsenic and valuable metals is 94.28%. At a SO2 concentration of 55%, the separation rate increases to 98.00%.

[0037] Comparative Example 1: CuS was used to control and separate arsenic from valuable metals in smelting flue gas, with a dosage of 50%, and other reaction conditions were the same as in Example 4. Figure 6 As shown, the separation rate of arsenic and valuable copper in flue gas controlled by CuS was 36.80%, which was much lower than the 94.36% of CuFe2S3 under the same conditions. CuFe2S3 was significantly better than CuS.

[0038] Comparative Example 2: FeS was used to control and separate arsenic from valuable metals in smelting flue gas, with an addition amount of 50%, and other reaction conditions were the same as in Example 4. Figure 6 As shown, the separation rate of arsenic and valuable metal copper in flue gas controlled by FeS was 41.27%, which was much lower than the 94.36% of CuFe2S3 under the same conditions. CuFe2S3 was significantly better than FeS.

[0039] Comparative Example 3: CuFeS2 was used for the control and separation of arsenic and valuable metals in smelting flue gas, with an addition amount of 50%, and other reaction conditions were the same as in Example 4. Figure 6 As shown, the separation rate of arsenic and valuable copper in flue gas controlled by CuFeS2 was 81.93%, which was lower than the 94.36% of CuFe2S3 under the same conditions. CuFe2S3 was significantly better than CuFeS2.

[0040] This invention prepared an arsenic phase modifier CuFe2S3 by mechanical ball milling, and verified its ability to regulate the phases of arsenic and metal oxides in smelting flue gas and inhibit the formation of arsenates in simulated smelting flue gas, thereby achieving the separation of arsenic from valuable metals in the flue gas.

[0041] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an arsenic phase modifier, characterized in that, The arsenic phase modifier is prepared by mechanical ball milling using chalcopyrite and sulfur powder as raw materials, wherein the mass ratio of chalcopyrite to sulfur powder is 3:1 to 5:1; the ball-to-material ratio of the mechanical ball milling is 10:1 to 20:1; the ball milling time is 2-6 h; and the obtained arsenic phase modifier is a compound or mixture having the chemical formula CuFe2S3.

2. The preparation method according to claim 1, characterized in that, The particle size after ball milling is <0.1mm.

3. An arsenic phase modifier prepared by the preparation method as described in claim 1 or 2.

4. A method for controlling the separation of arsenic and metal oxides in smelting flue gas, characterized in that, The arsenic phase modifier according to claim 3 is used as a modifier to inhibit the formation of arsenate, wherein the amount of the arsenic phase modifier is 40% to 60% of the total mass of arsenic and valuable metals; and the reaction temperature is 400 to 800°C.

5. The method according to claim 4, characterized in that, The smelting flue gas includes any one of copper smelting flue gas, lead smelting flue gas, and zinc smelting flue gas.

6. The method according to claim 4, characterized in that, The amount of the arsenic phase modifier is 50-60% of the total mass of arsenic and metal oxides.

7. The method according to claim 4, characterized in that, The reaction temperature is 600~700℃.

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