A method for removing arsenic from non-ferrous smelting arsenic-containing hazardous waste in a collaborative treatment

Abstract

The present application belongs to pyrometallurgical technical field, and particularly relates to a method for removing arsenic by co-processing non-ferrous smelting arsenic-containing hazardous waste. The method for removing arsenic by co-processing non-ferrous smelting arsenic-containing hazardous waste provided by the present application comprises the following steps: mixing different arsenic-containing hazardous wastes to obtain a mixture; the arsenic-containing hazardous waste comprises copper smelting arsenic-containing hazardous waste and arsenic sulfide residue, and the copper smelting arsenic-containing hazardous waste comprises copper smelting flue dust and / or black copper mud; roasting the mixture to obtain residues and volatiles, wherein the volatiles are arsenic-containing products, and the residues are other valuable metal compounds; the pressure range of the roasting is 1.01x10 5 ~1.33x10 ‑1 Pa. The method provided by the present application realizes harmless treatment, reduction and resource utilization of arsenic-containing solid waste by treating waste with waste; meanwhile, the method provided by the present application has high arsenic removal rate, short process flow, and is clean and environmentally friendly, and is suitable for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of pyrometallurgical technology, specifically relating to a method for the co-processing and removal of arsenic from arsenic-containing hazardous waste in non-ferrous smelting. Background Technology

[0002] Arsenic emissions from copper smelting account for over 80% of total emissions from non-ferrous metal smelting. Typically, over 70% of this arsenic is found in copper smelting dust from the flue gas collection process and in black copper sludge generated during the electrowinning and purification process of the circulating electrolyte in crude copper electrolytic refining. Arsenic sulfide slag is a hazardous waste (HW48) with an arsenic content that can reach up to 60% generated during the treatment of waste acid from non-ferrous smelting flue gas purification. Currently, the main treatment processes for copper smelting dust, black copper sludge, and arsenic sulfide slag include hydrometallurgy. Hydrometallurgical processes can select acid leaching or alkaline leaching depending on the form of arsenic in the raw materials. The commonly used reagents are concentrated sulfuric acid and NaOH. The addition of an oxidant can increase the arsenic leaching rate to over 90%, and further recovery of other valuable elements such as copper, lead, and sulfur can be achieved subsequently.

[0003] Currently, most companies typically use wet leaching processes to recover or store arsenic in the form of As2O3 or arsenates. This process is lengthy, has high production costs, and generates a large amount of arsenic-containing wastewater, posing significant safety hazards. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the co-processing and removal of arsenic from arsenic-containing hazardous waste in non-ferrous smelting. The method provided by this invention treats waste with waste, realizing the harmless and reduced-volume treatment and resource utilization of arsenic-containing solid waste. At the same time, the method provided by this invention has a high arsenic removal rate, a short process flow, and is clean and environmentally friendly, making it suitable for industrial application.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for the co-processing and removal of arsenic from arsenic-containing hazardous waste from non-ferrous smelting, comprising the following steps:

[0007] Arsenic-containing hazardous waste is mixed to obtain a mixture, wherein the arsenic-containing hazardous waste includes copper smelting arsenic-containing hazardous waste and arsenic sulfide slag, and the copper smelting arsenic-containing hazardous waste includes copper smelting dust and / or black copper sludge;

[0008] The mixture is calcined to obtain residues and volatiles. The volatiles are arsenic-containing products, and the residues are other valuable metal compounds. The calcination pressure range is 1.01 × 10⁻⁶. 5 ~1.33×10 -1 Pa.

[0009] Preferably, the main components of the copper smelting flue dust include: As 12-18%, Zn 14-20%, Pb 10-15%, Bi 4-6%, Cu 3-4%, Fe 4-6%, and Sn 0.5-1.5%; the main phases of the copper smelting flue dust include PbSO4, Zn(H2O)(OH)(AsO3), As2O3, As2O5, ZnSO4(H2O), Bi2O3, and SnO2.

[0010] Preferably, the main components of the black copper mud include: Cu 30-35%, As 20-35%, S 5-8%, Sb 0.5-1.5% and Ni 0.5-1%; the main phases of the black copper mud include As2O3, CuSO4·H2O, Cu5As2 and Cu3As.

[0011] Preferably, the main components of the arsenic sulfide slag include 20-40% As, 30-50% S, 2-3% Cd, 2.5-4% Na and 1-2.5% Pb; the main phases of the arsenic sulfide slag include As2O3, As2S3, S and PbSO4, and the As2S3 in the arsenic sulfide slag is in an amorphous form.

[0012] Preferably, the mass ratio of the copper smelting dust to the arsenic sulfide slag is 1:(0.5-4);

[0013] The mass ratio of the black copper mud to the arsenic sulfide slag is 1:(0.3-4).

[0014] Preferably, the roasting temperature is 400-800℃, and the roasting holding time is ≥20min.

[0015] Preferably, the heating rate from room temperature to the calcination temperature is 5–16 °C / min.

[0016] Preferably, the arsenic-containing product includes one or more of arsenic oxides, arsenic sulfides, and elemental arsenic.

[0017] Preferably, the other valuable metal compounds include one or more of copper sulfides, lead sulfides, and zinc oxides.

[0018] Preferably, before mixing, the process further includes: pre-treating the arsenic-containing hazardous waste from copper smelting and the arsenic sulfide slag separately, wherein the pre-treatment includes drying, grinding and sieving;

[0019] The drying temperature is 105–300℃, and the time is 5–24 hours;

[0020] The separating sieve used for screening is an 80-mesh sieve or a 100-mesh sieve.

[0021] This invention provides a method for the co-processing and arsenic removal of arsenic-containing hazardous waste from non-ferrous smelting, comprising the following steps: mixing the arsenic-containing hazardous waste to obtain a mixture, wherein the arsenic-containing hazardous waste includes arsenic-containing hazardous waste from copper smelting and arsenic sulfide slag, and the arsenic-containing hazardous waste from copper smelting includes copper smelting dust and / or black copper sludge; calcining the mixture to obtain residues and volatiles, wherein the volatiles are arsenic-containing products, and the residues are other valuable metal compounds; the calcination pressure range is 1.01 × 10⁻⁶. 5 ~1.33×10 -1 This invention utilizes a mixture of various arsenic-containing hazardous wastes generated in the metallurgical industry, such as arsenic sulfide slag, copper smelting dust, and / or black copper sludge, followed by roasting. During roasting, the stable arsenic-containing compounds in the arsenic-containing hazardous wastes (copper smelting dust, black copper sludge) react with the arsenic sulfide slag, and the components in the copper smelting hazardous wastes (black copper sludge) react with each other to generate easily volatile arsenic-containing products, releasing the toxic element arsenic; the residue obtained is other valuable metal compounds. Simultaneously, this invention controls the roasting pressure range to 1.01 × 10⁻⁶. 5 ~1.33×10 -1 Pa can significantly increase the evaporation rate of volatile arsenic-containing products, while valuable metals are enriched in the residue, thus achieving effective separation of toxic arsenic and other valuable metals. The method provided by this invention not only has a simple process flow and high arsenic removal efficiency, applicable to the co-processing of arsenic-containing hazardous waste and arsenic sulfide slag, but also provides a good working environment, is clean and efficient without generating secondary pollution. The enrichment of valuable metals in the residue further enables selective recovery and recycling of valuable metals from arsenic-containing materials, comprehensively improving resource utilization efficiency. Example results show that the method provided by this invention removes arsenic from common arsenic-containing materials in non-ferrous smelting (copper dust, black copper sludge, and arsenic sulfide slag) with an arsenic removal rate of over 95%. In summary, the method provided by this invention treats waste with waste, achieving harmless and reduced-volume treatment and resource utilization of arsenic-containing solid waste; simultaneously, the method provided by this invention has a high arsenic removal rate, a short process flow, and is clean and environmentally friendly, making it suitable for industrial application. Attached Figure Description

[0022] Figure 1 A process flow diagram of the method for co-processing and removing arsenic from arsenic-containing hazardous waste in non-ferrous smelting provided by the present invention;

[0023] Figure 2 The X-ray diffraction pattern of the arsenic sulfide slag raw material used in the embodiments of the present invention;

[0024] Figure 3 The X-ray diffraction pattern of the black copper mud raw material used in the embodiments of the present invention;

[0025] Figure 4The X-ray diffraction pattern of the copper fume raw material used in the embodiments of the present invention;

[0026] Figure 5 The X-ray diffraction pattern of the condensate obtained in Example 1 of this invention;

[0027] Figure 6 The X-ray diffraction pattern of the residue obtained in Example 1 of this invention;

[0028] Figure 7 The image shows the X-ray diffraction pattern of the residue obtained in Example 3 of this invention. Detailed Implementation

[0029] This invention provides a method for the co-processing and removal of arsenic from arsenic-containing hazardous waste from non-ferrous smelting, comprising the following steps:

[0030] Arsenic-containing hazardous waste is mixed to obtain a mixture, wherein the arsenic-containing hazardous waste includes copper smelting arsenic-containing hazardous waste and arsenic sulfide slag, and the copper smelting arsenic-containing hazardous waste includes copper smelting dust and / or black copper sludge;

[0031] The mixture is calcined to obtain residues and volatiles. The volatiles are arsenic-containing products, and the residues are other valuable metal compounds. The calcination pressure range is 1.01 × 10⁻⁶. 5 (i.e., normal pressure) ~ 1.33 × 10 -1 Pa.

[0032] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0033] The present invention provides a method for the co-processing and removal of arsenic from arsenic-containing hazardous waste in non-ferrous smelting. The process is short, and the arsenic removal rate is maintained at over 90%. It achieves the harmless and reduced-volume treatment of arsenic-containing hazardous waste (copper smelting dust, black copper sludge, and arsenic sulfide slag), and is clean and environmentally friendly.

[0034] This invention involves mixing arsenic-containing hazardous waste to obtain a mixture. The arsenic-containing hazardous waste includes arsenic-containing hazardous waste from copper smelting and arsenic sulfide slag. The arsenic-containing hazardous waste from copper smelting includes copper smelting dust and / or black copper sludge. In this invention, the main components of the copper smelting dust preferably include: As 12-18%, Zn 14-20%, Pb 10-15%, Bi 4-6%, Cu 3-4%, Fe 4-6%, and Sn 0.5-1.5%. The main phases of the copper smelting dust preferably include PbSO4, Zn(H2O)(OH)(AsO3), As2O3, As2O5, ZnSO4(H2O), Bi2O3, and SnO2. The main components of the black copper sludge preferably include: Cu 30-35%, As 20-35%, S 5-8%, Sb 0.5-1.5%, and Ni 0.5-1%. The main phases of the black copper sludge preferably include As₂O₃, CuSO₄·H₂O, Cu₅As₂, and Cu₃As. The main components of the arsenic sulfide slag preferably include 20-40% As, 30-50% S, 2-3% Cd, 2.5-4% Na, and 1-2.5% Pb. The main phases of the arsenic sulfide slag preferably include As₂O₃, As₂S₃, S, and PbSO₄, and the As₂S₃ in the arsenic sulfide slag is preferably in an amorphous form.

[0035] In this invention, the preferred mass ratio of copper smelting dust to arsenic sulfide slag is 1:(0.5-4), more preferably 1:(1-3), and in the embodiments, it can be 1:2 or 1:1. The preferred mass ratio of black copper sludge to arsenic sulfide slag is 1:(0.3-4), more preferably 1:(0.5-4), and even more preferably 1:(1-2), and in the embodiments, it can be 1:4, 1:0.8, or 1:1. When the arsenic-containing hazardous waste includes copper smelting dust and black copper sludge, the present invention calculates the amount of arsenic sulfide slag by calculating the mass ratio of copper smelting dust to arsenic sulfide slag and the mass ratio of black copper sludge to arsenic sulfide slag separately, and then summing them.

[0036] In this invention, prior to the mixing, the invention preferably further includes pretreatment of the arsenic-containing hazardous waste from copper smelting and the arsenic sulfide slag, respectively, wherein the pretreatment includes drying, grinding, and sieving. In this invention, the drying temperature is preferably 105–300°C, and the drying time is preferably 5–24 hours. In this invention, the drying temperature of the copper smelting dust is more preferably 200–300°C, and the drying time is preferably 5–24 hours, more preferably 8–20 hours, and even more preferably 9–12 hours. The drying temperature of the black copper sludge is preferably 105–200°C, more preferably 110–180°C, and even more preferably 120–150°C; the drying time is preferably 5–24 hours, more preferably 8–20 hours, and even more preferably 9–12 hours. The drying temperature of the arsenic sulfide slag is preferably 105–200°C, more preferably 110–180°C, and even more preferably 120–150°C; the drying time is preferably 5–24 hours, more preferably 8–20 hours, and even more preferably 9–12 hours. The grinding is preferably carried out in a pulverizer or a mortar. The present invention does not have special requirements regarding the specific implementation of the grinding process. The separating sieve used for sieving is preferably an 80-mesh or 100-mesh sieve, specifically made of stainless steel. The sieving process collects the undersize material.

[0037] In this invention, the preferred order of grinding, sieving and drying is: grinding, sieving and drying are performed sequentially, or drying, grinding and sieving are performed sequentially.

[0038] The present invention does not have any special requirements for the specific implementation method of mixing the arsenic-containing hazardous waste.

[0039] After obtaining the mixture, the present invention calcines the mixture to obtain residues and volatiles. The volatiles are arsenic-containing products, and the residues are other valuable metal compounds. The calcination pressure range is 1.01 × 10⁻⁶. 5 ~1.33×10 -1 Pa. In this invention, the roasting is preferably carried out in a tube furnace, specifically a vacuum tube furnace or a tube resistance furnace. Before roasting, the tube furnace can be connected to a gas purification device. In a specific embodiment of this invention, the roasting is carried out in a vacuum environment or in a semi-open state. When operating in a semi-open state, the roasting pressure is atmospheric pressure (1.01 × 10⁻⁶ Pa). 5 (Pa), the material can come into contact with air. In this invention, when the roasting is carried out in a vacuum environment, it is called vacuum roasting. This invention preferably uses an inert gas atmosphere for vacuum roasting, and the inert gas is preferably argon. The preferred implementation of the vacuum roasting method includes: first, connecting the vacuum roasting apparatus to a vacuum reaction system; then, introducing an inert gas through one end of the vacuum roasting apparatus and adjusting the pressure of the vacuum roasting apparatus; the inert gas is preferably argon.

[0040] In this invention, the calcination pressure is 1.01 × 10⁻⁶. 5 Pa ~ 1.33 × 10 -1 Pa, preferably 1 to 50000 Pa, more preferably 1 to 1000 Pa, and in the examples it can be 1 Pa, atmospheric pressure (1.01 × 10⁻⁶ Pa). 5 Pa), 80 Pa, or 20000 Pa. When the calcination is carried out in a vacuum environment, the preferred method for adjusting the calcination pressure includes: connecting a vacuum tube furnace to a vacuum reaction system, and then introducing an inert gas through one end of the vacuum tube furnace to adjust the pressure of the vacuum tube furnace; the inert gas is preferably argon.

[0041] In this invention, the calcination temperature is preferably 500–800°C, more preferably 550–700°C, and even more preferably 600–700°C. In the embodiments, it can be 700°C, 600°C, or 650°C. The calcination holding time is preferably ≥20 min, more preferably ≥30 min, even more preferably 30–120 min, and most preferably 60–100 min. In the embodiments, it can be 120 min, 100 min, 60 min, or 3 h. The heating rate from room temperature to the calcination temperature is preferably 5–16°C / min, more preferably 10–15°C / min, even more preferably 11–14°C / min, and most preferably 12–13°C / min. In the embodiments, it can be 13°C / min, 12°C / min, 10°C / min, or 14°C / min. This invention utilizes the strong metal-sulfur bonding principle to react elemental sulfur and sulfides in arsenic sulfide slag with stable arsenic compounds in arsenic-containing hazardous waste (copper smelting dust and / or black copper sludge), transforming them into arsenic oxides, arsenic sulfides, and elemental arsenic with high saturated vapor pressures. The volatiles are then volatilized to obtain volatiles. Preferably, these volatiles are condensed in the low-temperature zone of the vacuum tube furnace at a temperature of 50–300°C. The arsenic-containing products obtained from condensation preferably include one or more of arsenic oxides, arsenic sulfides, and elemental arsenic, with the main phases of the arsenic-containing products preferably being As₂O₃ and As₄S₄.

[0042] In this invention, the main reactions that may occur during the calcination include the following:

[0043] (1) Cu3As + 3 / 4S2(g) = 3 / (2-x)Cu 2-x S + 1 / 4As₄(g);

[0044] (2)Cu5As2+5 / 4S2(g)=5 / (2-x)Cu 2-x S + 1 / 2 As₄(g);

[0045] (3)Cu3As+As2S3(g)=3CuS+3 / 4As4(g);

[0046] (4)Cu3As+3 / 4CuSO4=15 / 4Cu+1 / 4As4O6(g)+3 / 4SO2(g);

[0047] (5)As4(g)+2S2(g)=As4S4(g);

[0048] (6)As4O6(g)+7 / 2S2(g)=As4S4(g)+3SO2(g);

[0049] (7)Me3(AsO4)2+11 / 4S2(g)=3MeS+1 / 2As4O6(g)+5 / 2SO2(g);

[0050] (8)Me3(AsO4)2+11 / 9As2S3(g)→3MeS+10 / 9As4O6(g)+2 / 3SO2(g);

[0051] (9)Bi2O3+3 / 4S2(g)=2Bi+3 / 2SO2(g);

[0052] (10)PbSO4+S2(g)=PbS+2SO2(g);

[0053] (11)PbSO4+4 / 9As2S3(g)=PbS+2 / 9As4O6(g)+4 / 3SO2(g).

[0054] In this invention, during the roasting process, valuable metals such as copper, lead, and zinc from the arsenic-containing hazardous waste are enriched in the residue after arsenic removal from the arsenic sulfide slag. The toxic element arsenic evaporates as a gas under the high-temperature conditions of roasting, and is condensed and collected in the low-temperature zone, achieving selective separation of arsenic. The residue after enrichment with valuable metals achieves volume reduction and detoxicity reduction, and can be directly returned to the main non-ferrous smelting process for recycling. In this invention, the other valuable metal compounds include one or more of copper sulfides, lead sulfides, and zinc oxides. In this invention, after roasting, the roasting residue is preferably cooled to ≤150°C before being removed.

[0055] In this invention, the SO2 flue gas generated during the roasting process is preferably fed into an acid production system to produce sulfuric acid.

[0056] The method for co-processing and removing arsenic from arsenic-containing hazardous waste in non-ferrous smelting provided by the present invention preferably includes the following steps: thoroughly mixing the arsenic-containing hazardous waste with arsenic sulfide slag and then roasting it; the roasting process is carried out at 1.01 × 10⁻⁶ ℃. 5 ~1.33×10 -1The process is carried out under Pa conditions. This invention utilizes the mutual reaction between the components in arsenic sulfide slag and arsenic-containing hazardous waste, and achieves the separation of arsenic and other valuable metals through calcination at 400℃~800℃. The method provided by this invention is simple, highly operable, and can achieve the low-toxicity and volume reduction treatment of arsenic-containing hazardous waste, improving the recycling level of the non-ferrous smelting industry. Using the method provided by this invention to treat arsenic-containing hazardous waste and arsenic sulfide slag, the comprehensive arsenic removal rate can reach over 90%.

[0057] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0058] The following embodiments provide a flowchart of a method for co-processing and removing arsenic from arsenic-containing hazardous waste in non-ferrous smelting. Figure 1 As shown.

[0059] Example 1

[0060] This embodiment provides a method for co-processing and removing arsenic from arsenic-containing hazardous waste from non-ferrous smelting, specifically including the following steps:

[0061] Arsenic sulfide slag and black copper mud were dried separately at 120℃ for 10 hours, then ground in a pulverizer and finally sieved through a 100-mesh stainless steel sieve. 10g of the sieved material from each arsenic sulfide slag and black copper mud was weighed out, mixed thoroughly, and placed in a corundum crucible. The crucible was placed in a quartz tube inside a vacuum tube furnace, and the vacuum reaction system was connected. Argon gas was introduced through one end of the vacuum tube furnace, and the vacuum pump was turned on to evacuate the furnace. The pressure of the vacuum tube furnace was adjusted. When the residual pressure in the reaction apparatus reached 1 Pa, the calcination temperature was controlled at 600℃, with a heating rate of 14℃ / min. The temperature was increased from room temperature to 600℃, and held at 600℃ for 120 minutes. After the reaction, the mixture was allowed to cool naturally. A large amount of yellow and orange-red condensate was obtained in the low-temperature zone. When the furnace temperature dropped below 150℃, the crucible was removed. X-ray fluorescence spectroscopy was used to test the residue in the crucible, which contained 9.13% As and Cu. The content of copper was 35.86%, the content of sulfur was 18.51%, the weight loss rate was 54.45%, the arsenic volatilization rate reached 91.12%, and the direct recovery rate of copper was 97.9%. The direct recovery rate refers to the content of elemental composition in the residue / the content of initial raw material composition.

[0062] Example 2

[0063] This embodiment provides a method for co-processing and removing arsenic from arsenic-containing hazardous waste from non-ferrous smelting, specifically including the following steps:

[0064] Black copper mud and arsenic sulfide slag were dried separately at 150℃ for 5 hours. The dried samples were then ground in a mortar and sieved through a 100-mesh stainless steel sieve. 10g of the sieved material from the black copper mud and 8g of the arsenic sulfide slag were weighed out, mixed thoroughly, and placed in a crucible. The crucible was placed in the heating center of the quartz tube inside a tube-type resistance furnace. One end of the quartz tube was sealed, and the other end was connected to a gas purification device. The temperature was adjusted to 650℃, and the heating rate was controlled at 10℃ / min. The temperature was raised to 650℃ under normal pressure (1.01×10⁻⁶). 5 The mixture was kept at a constant temperature (Pa) for 100 minutes after the reaction, and then allowed to cool naturally after the reaction was completed. A large amount of yellow and white condensate was obtained in the low-temperature zone. When the temperature inside the furnace dropped below 150°C, the crucible was removed. The residue in the crucible contained 9.51% As, 36.99% Cu, and 19.15% S, with a weight loss rate of 53.05%, an arsenic volatilization rate of 90.07%, a direct recovery rate of >99%, and virtually no loss of copper.

[0065] Example 3

[0066] This embodiment provides a method for co-processing and removing arsenic from arsenic-containing hazardous waste from non-ferrous smelting, specifically including the following steps:

[0067] Copper smelting dust was dried in an electric blast drying oven at 260℃ for 8 hours, and arsenic sulfide slag was dried in an electric blast drying oven at 105℃ for 8 hours. The dried copper smelting dust and arsenic sulfide slag were then ground separately in a pulverizer and sieved through a 100-mesh stainless steel sieve. 10g each of the sieved arsenic sulfide slag and copper smelting dust were weighed, mixed thoroughly, and placed in a corundum crucible. The crucible was placed in a vacuum tube furnace, and the vacuum reaction system was connected. Argon gas was introduced into one end of the vacuum tube furnace, and the vacuum pump was turned on to evacuate the furnace. The pressure inside the vacuum tube furnace was adjusted. When the residual pressure in the reaction apparatus reached 80Pa, the calcination temperature was adjusted to 600℃, the heating rate was controlled at 12℃ / min, and the temperature was held for 60min. After the reaction was completed, the furnace was allowed to cool naturally. When the temperature inside the furnace drops below 150°C, the crucible is removed. The residue in the crucible contains 3.05% As, 6.12% Cu, 20.07% Zn, and 14.17% S. The weight loss rate is 57.4%, the arsenic volatilization rate reaches 94.39%, the direct copper recovery rate is >99%, and there is basically no copper loss.

[0068] Example 4

[0069] Arsenic sulfide slag was dried at 110℃ for 24 hours, black copper mud was dried at 150℃ for 10 hours, and copper smelting dust was dried at 200℃ for 12 hours. Then, arsenic sulfide slag, black copper mud, and copper smelting dust were ground separately using a pulverizer and sieved through a 100-mesh stainless steel sieve. 40g of the arsenic sulfide slag undersize, 5g of the black copper mud undersize, and 20g of the copper smelting dust undersize were weighed separately. The mass ratio of copper smelting dust to arsenic sulfide slag was 1:2, and the mass ratio of black copper mud to arsenic sulfide slag was 1:4. The three materials were mixed evenly and placed in a ceramic boat. The ceramic boat was placed in a vacuum tube furnace, and the vacuum reaction system was connected. Argon gas was introduced into one end of the vacuum tube furnace, and the vacuum pump was turned on to evacuate the furnace. The pressure inside the vacuum tube furnace was adjusted. When the residual pressure inside the vacuum tube furnace stabilized at 20000 Pa, the calcination temperature was adjusted to 700℃, the heating rate was controlled at 13℃ / min, and the temperature was held for 3 hours. After the reaction was completed, the furnace was allowed to cool naturally. When the temperature inside the furnace dropped below 150℃, the crucible was removed. The residue in the crucible contained 2.48% As and 2.48% Cu. The composition was 7.87%, Zn 15.43%, S 16.83%, with a weight loss rate of 61.50%, an arsenic volatilization rate of 98.47%, and a copper direct recovery rate of 98.78%.

[0070] Figure 1 This invention provides a process flow diagram for the co-processing and arsenic removal of arsenic-containing hazardous waste from non-ferrous smelting. The invention first mixes the arsenic-containing hazardous waste with arsenic sulfide slag, and then... (The sentence is incomplete and requires more context to translate accurately.) 5 ~1.33×10 -1 Calcination under Pa conditions yields volatile arsenic-containing products and residues enriched with valuable metals such as Cu, Zn, and Pb, achieving selective separation of the toxic element arsenic.

[0071] X-ray diffraction analysis was performed on the arsenic sulfide slag raw material and black copper sludge raw material used in Example 1 of this invention, and the results were obtained respectively. Figure 2 and Figure 3 The X-ray diffraction pattern shown is based on... Figure 2 It can be seen that the main phases of the arsenic sulfide slag raw material used in Example 1 of the present invention are S8, As2O3 and PbSO4. Figure 3 It can be seen that the main phases of the black copper sludge raw material used in Example 1 of this invention are As2O3, CuSO4·H2O, Cu5As2, and Cu3As. The XRD patterns of the arsenic sulfide slag raw material and the black copper sludge raw material used in Example 2 are the same as those in Example 1. The XRD pattern of the arsenic sulfide slag raw material used in Example 3 is the same as that in Example 1.

[0072] The XRD patterns of the arsenic sulfide slag raw material and black copper mud raw material used in Example 4 are the same as those in Example 1.

[0073] The copper smelting dust raw material used in Example 3 of this invention was subjected to X-ray diffraction analysis using an X-ray diffractometer to obtain... Figure 4 The X-ray diffraction pattern shown is based on... Figure 4 It can be seen that the main phases of the copper smelting dust raw material used in Example 3 of the present invention are PbSO4, Zn(H2O)(OH)(AsO3), As2O3, ZnSO4(H2O), Bi2O3 and SnO2. The XRD pattern of the copper smelting dust raw material used in Example 4 is the same as that in Example 3.

[0074] The condensate and residue obtained in Example 1 of this invention were analyzed by X-ray diffraction using an X-ray diffractometer. The results are as follows: Figure 5 and Figure 6 The X-ray diffraction pattern is shown in the image. Figure 5 and Figure 6 It can be seen that the main components of the condensate obtained in Example 1 of the present invention are As2O3 and As4S4, and the main components of the residue are CuS and Cu. 7.2 S4 enables the efficient separation of arsenic and other valuable metals.

[0075] The residue obtained in Example 3 of this invention was analyzed by X-ray diffraction using an X-ray diffractometer. The results are as follows: Figure 7 The X-ray diffraction pattern is shown in the image. Figure 7 It can be seen that the main components of the residue obtained in Example 3 of the present invention are PbS, SnO2, Bi and Bi2O3, indicating that arsenic and other valuable metals were successfully separated.

[0076] As can be seen from the above embodiments, the method for co-processing and removing arsenic from arsenic-containing hazardous waste in non-ferrous smelting provided by the present invention is not only simple in process but also highly efficient. The arsenic removal rate can reach more than 98%, the arsenic content in the residue is reduced to less than 3%, and no secondary pollution is generated. Valuable metals are enriched in the residue and can be directly returned to the main process of non-ferrous smelting for recycling.

[0077] Comparative Example 1

[0078] The ground copper smelting dust was dried in an electric heating drying oven at 240℃ for 4 hours. 100g of the dried copper smelting dust was weighed and placed in a vacuum reactor for calcination. First, the vacuum reactor was connected to the vacuum reaction system. Then, argon gas was introduced into one end of the vacuum tube furnace, and the vacuum pump was turned on to evacuate the furnace. The pressure in the vacuum tube furnace was adjusted. When the residual pressure inside the vacuum reactor reached 10Pa, the calcination temperature was adjusted to 700℃, the heating rate was controlled at 14℃ / min, and the temperature was maintained for 5 hours. After the reaction, the furnace was allowed to cool naturally. When the temperature inside the furnace dropped below 100℃, the reactor was removed. The residue contained 16.07% As, 4.52% Cu, 19.17% Zn, and 3.24% S, with a weight loss of 6.22%, an arsenic volatilization rate of only 1%, and a direct copper recovery rate of 95.76%.

[0079] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. Other embodiments can be obtained based on these embodiments without creative intent, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for co-processing and removing arsenic from arsenic-containing hazardous waste from non-ferrous smelting, characterized in that, Includes the following steps: Arsenic-containing hazardous waste is mixed to obtain a mixture, wherein the arsenic-containing hazardous waste includes copper smelting dust and arsenic sulfide slag. The main components of the copper smelting dust include: As 12~18%, Zn 14~20%, Pb 10~15%, Bi 4~6%, Cu 3~4%, Fe 4~6%, and Sn 0.5~1.5%; the mass ratio of the copper smelting dust to the arsenic sulfide slag is 1:(1~3). The mixture is calcined to obtain residues and volatiles. The volatiles are arsenic-containing products, and the residues are other valuable metal compounds. The calcination pressure range is 1.01 × 10⁻⁶. 5 ~1.33×10 -1 Pa, the calcination temperature is 400~800℃, and the calcination holding time is ≥20 min.

2. The method according to claim 1, characterized in that, The main phases of the copper smelting flue dust include PbSO4, Zn(H2O)(OH)(AsO3), As2O3, As2O5, ZnSO4(H2O), Bi2O3, and SnO2.

3. The method according to claim 1, characterized in that, The main components of the arsenic sulfide slag include 20-40% As, 30-50% S, 2-3% Cd, 2.5-4% Na and 1-2.5% Pb; the main phases of the arsenic sulfide slag include As2O3, As2S3, S and PbSO4, and the As2S3 in the arsenic sulfide slag is in an amorphous form.

4. The method according to claim 1, characterized in that, The heating rate from room temperature to the calcination temperature is 5~16 °C / min.

5. The method according to claim 1, characterized in that, The arsenic-containing products include one or more of arsenic oxides, arsenic sulfides, and elemental arsenic.

6. The method according to claim 1, characterized in that, The other valuable metal compounds include one or more of copper sulfides, lead sulfides, and zinc oxides.

7. The method according to claim 1, characterized in that, Prior to the mixing, the process further includes: pre-treating the arsenic-containing hazardous waste from copper smelting and the arsenic sulfide slag separately, wherein the pre-treatment includes drying, grinding and sieving; The drying temperature is 105~300 ℃, and the time is 5~24 h; The separating sieve used for screening is an 80-mesh sieve or a 100-mesh sieve.

Images