Method for comprehensively utilizing arsenic-rich ash in copper smelting

Abstract

The invention discloses a copper smelting arsenic-rich ash comprehensive utilization method, and relates to the field of valuable metal recovery, and the method comprises the following steps: S1, arsenic-rich ash pretreatment; s2, low-temperature sulfuric acid curing; s3, condensing and collecting AsO; s4, reduction smelting of the cured material; s5, valuable metal extraction; the arsenic removal rate is extremely high: the low-temperature sulfuric acid curing and multi-stage gradient condensation synergistic technology is adopted, so that the arsenic removal rate is high; the recovery rates of copper, lead, zinc and gold are high through curing phase regulation and control and reduction smelting slag type optimization; the energy consumption is greatly reduced; high-value utilization of arsenic resources is realized; the environmental benefits are outstanding; through pretreatment and parameter optimization, the method can adapt to arsenic-rich ash with different components, the fluctuation range of the arsenic removal rate and the metal recovery rate is smaller than or equal to 2%, and the fluctuation range in the prior art is generally + / -10%; the product quality is excellent.

Description

Technical Field

[0001] This invention relates to the field of valuable metal recycling technology, specifically to a method for the comprehensive utilization of arsenic-rich ash from copper smelting. Background Technology

[0002] Copper smelting generates a large amount of fumes, among which arsenic-rich ash (also known as white fumes) is a typical hazardous solid waste. Its arsenic content is usually as high as 10-30 wt%, and it is accompanied by various valuable metals such as copper, lead, zinc, gold, and silver. If not handled properly, it will not only cause environmental pollution from arsenic (arsenic and its compounds are highly toxic and carcinogenic, and can easily spread through water, soil, and atmosphere, harming the ecological environment and human health), but also lead to the waste of valuable metal resources. Therefore, achieving the safe removal of arsenic from arsenic-rich ash and the efficient recovery of valuable metals is one of the key issues for the sustainable development of the copper smelting industry.

[0003] Currently, the treatment methods for arsenic-rich ash are mainly divided into three categories: pyrometallurgical treatment, wet treatment, and combined treatment, but all of them have obvious drawbacks.

[0004] 1. Pyrometallurgical treatment is a traditional method for arsenic removal, mainly involving high-temperature roasting to volatilize arsenic as As₂O₃, followed by collection. For example, patent CN108642362A discloses a method for arsenic removal and recovery of valuable metals from copper smelting flue dust by roasting the flue dust with additives at 600-800℃. However, this method has the following problems: First, the roasting temperature is high (usually >600℃), resulting in high energy consumption, and the high temperature easily leads to the oxidation of metals such as copper and lead, forming insoluble substances, reducing the subsequent recovery rate; second, arsenic volatilization is incomplete, and the arsenic removal rate of traditional pyrometallurgical roasting is usually only 85-90%, with residual arsenic remaining in the roasting slag, requiring further treatment; third, secondary pollution is easily generated during the high-temperature roasting process, such as incomplete collection of As₂O₃ flue gas, which will be directly emitted into the atmosphere, causing pollution.

[0005] 2. Wet treatment technology mainly separates arsenic from metals through acid leaching and alkaline leaching, but it has poor selectivity and consumes a lot of reagents. For example, patent CN110128425A uses a sulfuric acid-hydrogen peroxide system to leach arsenic-rich flue dust. Although it can dissolve some metals, the arsenic leaching rate is only 80-85%, and arsenic and metal ions coexist in the leachate, making subsequent separation difficult. Alkaline leaching requires a large amount of strong alkali, which is costly, and the metal grade in the leaching residue is low, limiting its recovery value. In addition, the arsenic-containing wastewater generated by wet treatment is difficult to treat, and improper treatment can easily cause secondary pollution, such as arsenic accumulating in the form of sludge, posing a long-term environmental risk.

[0006] 3. Combined processing technologies attempt to combine the advantages of pyrometallurgical and hydrometallurgical processes, but the process integration is poor. For example, pyrometallurgical arsenic removal followed by hydrometallurgical leaching of metals is used, but the roasted slag after pyrometallurgical arsenic removal has a dense structure, resulting in a low metal dissolution rate during hydrometallurgical leaching. Alternatively, some metals may be hydrometallurgically leached first, followed by pyrometallurgical arsenic removal. In this case, the arsenic content in the leaching slag increases, making pyrometallurgical arsenic removal more difficult and prone to incomplete arsenic volatilization. At the same time, existing combined processes generally suffer from problems such as complex processes, harsh operating conditions, and large equipment investment, making it difficult to achieve industrial application.

[0007] From the perspective of resource recycling, existing technologies have a low overall recovery rate of multiple metals in arsenic-rich ash. Traditional methods often focus only on the recovery of a single metal (such as copper), while neglecting the recovery of rare and precious metals such as lead, zinc, and gold, leading to resource waste. For example, after pyrometallurgical roasting, the matte phase only enriches copper and lead, while zinc is easily lost in the slag phase. In wet leaching, lead easily forms lead sulfate precipitate and remains in the slag, while gold is lost due to its difficulty in dissolving. The overall recovery rate of multiple metals is usually less than 85%, which is far from meeting the requirements for efficient resource utilization.

[0008] From an environmental perspective, existing technologies for arsenic treatment lack a systematic approach; some methods temporarily store arsenic in the form of arsenic-containing sludge or waste residue, failing to achieve safe solidification or high-value utilization of arsenic, thus posing a risk of "secondary pollution"; other methods can recover As2O3, but the product purity is low (usually <95%), limiting its application, and the flue gas purification process is incomplete, still posing a risk of arsenic emissions.

[0009] In addition, the existing technology has poor process stability and is greatly affected by the fluctuation of arsenic-rich ash composition. Due to the large differences in the composition of arsenic-rich ash among different copper smelting enterprises (such as the fluctuation range of arsenic, copper and lead content can reach 5-30wt%), the existing process parameters are difficult to adapt to the composition changes, resulting in large fluctuations in arsenic removal rate and metal recovery rate (fluctuation range can reach ±10%), which affects the stability of industrial production.

[0010] In summary, existing arsenic-rich ash treatment technologies suffer from problems such as low arsenic removal rate, low multi-metal recovery rate, high energy consumption, high pollution risk, and poor process stability.

[0011] Therefore, developing a comprehensive utilization method for arsenic-rich ash that is low in energy consumption, has a high arsenic removal rate, a high metal recovery rate, and is environmentally friendly has important practical significance and application value. Summary of the Invention

[0012] To address the problems existing in the prior art, this invention provides a method for the comprehensive utilization of arsenic-rich ash from copper smelting, solving the problems of low arsenic removal rate, low multi-metal recovery rate, high energy consumption, high pollution risk, and poor process stability in existing copper smelting arsenic-rich ash treatment technologies.

[0013] To achieve the above objectives, the present invention employs a method for the comprehensive utilization of arsenic-rich ash from copper smelting, comprising: S1, Arsenic-rich ash pretreatment: The arsenic-rich ash from copper smelting is screened to remove impurities with a particle size >5mm, resulting in pretreated arsenic-rich ash; S2, Low-temperature sulfuric acid curing: Pretreated arsenic-rich ash is mixed with sulfuric acid solution at a liquid-solid ratio of 1:1-5:1 and stirred at 50-120℃ for 1-5 hours. The mass concentration of sulfuric acid solution is controlled at 10-50% to obtain cured material and flue gas containing As2O3. S3, As2O3 condensation and collection: The flue gas containing As2O3 generated by S2 is introduced into a multi-stage condensation system after dust removal. The first-stage condensation temperature is controlled at 100-150℃, the second-stage condensation temperature at 50-90℃, and the flue gas velocity at 0.5-2m / s. As2O3 product is collected. S4, Reduction Smelting of Cemented Material: The chopped material obtained in S2 is mixed with carbonaceous reducing agent at a mass ratio of 100:5-15, flux is added to adjust the slag shape, and reduction smelting is carried out at 1000-1200℃ for 2-4 hours to achieve the separation of slag-matte-gold three phases and obtain smelting slag, metallic matte and gold-containing enrichment. S5, valuable metal extraction: Subsequent hydrometallurgical or pyrometallurgical processes are performed on the metal matte and gold-bearing concentrates in S4 to recover valuable metals such as copper, lead, zinc, and gold.

[0014] As a further optimization of the above scheme, in S1, the composition of the arsenic-rich ash is: As 10-30wt%, Cu 5-15wt%, Pb 3-10wt%, Zn 2-8wt%, Au 1-5g / t, and the particle size is controlled at 0.1-5mm after sieving.

[0015] As a further optimization of the above scheme, in S2, the mass concentration of the sulfuric acid solution is 15-45%, and the stirring rate is 200-400 r / min.

[0016] As a further optimization of the above scheme, in S3, the multi-stage condensation system includes a primary condensation tower and a secondary condensation tower, wherein the primary condensation is cooled by water and the secondary condensation is cooled by refrigerant. The dust content of the flue gas after dust removal is ≤0.1g / m³.

[0017] As a further optimization of the above scheme, in S4, the carbonaceous reducing agent is coke or anthracite, with a fixed carbon content ≥85%; The flux is a mixture of SiO2 and CaO in a mass ratio of 1:0.6-1.8, and the amount of flux added is 6-14% of the mass of the calcined material.

[0018] As a further optimization of the above scheme, in S4, nitrogen gas is introduced into the furnace for protection during reduction smelting, with a nitrogen flow rate of 0.7-1.8 L / min.

[0019] As a further optimization of the above scheme, in S5, the metal matte is subjected to selective oxidation leaching treatment, the leaching agent is sulfuric acid solution, the leaching temperature is controlled at 60-80℃, the sulfuric acid concentration is 5-20%, and the leaching time is 1-3h, so as to achieve the separation of copper, zinc and lead.

[0020] As a further optimization of the above scheme, the low-temperature sulfuric acid ripening reaction is carried out in a glass-lined reactor or a 316L stainless steel reactor; the reduction smelting is carried out in a medium-frequency induction furnace or a resistance furnace.

[0021] The present invention provides a method for the comprehensive utilization of arsenic-rich ash from copper smelting, which has the following beneficial effects: The present invention provides a method for the comprehensive utilization of arsenic-rich ash from copper smelting, achieving an extremely high arsenic removal rate: a combined low-temperature sulfuric acid curing and multi-stage gradient condensation technology is employed, resulting in a high arsenic removal rate. The comprehensive recovery rate of multiple metals is significantly improved: through the regulation of maturation phase and optimization of reduction smelting slag, the recovery rates of copper, lead, zinc and gold are high; Energy consumption is significantly reduced and costs are significantly lowered: the low-temperature sulfuric acid ripening reaction temperature is only 50-120℃, which reduces energy consumption by more than 60% compared with the traditional fire roasting (600-800℃). The process steps are simple, the reagent consumption is low, and the overall treatment cost is reduced by 20-30%, which has significant economic benefits. High-value utilization of arsenic resources: As2O3 products obtained through multi-stage condensation and collection have a purity of ≥99% and can be directly used as industrial raw materials in fields such as glass and wood preservation. The environmental benefits are outstanding: After dust removal and condensation purification, the arsenic emission concentration of flue gas is low, and it can be safely stored or used as a building material raw material, truly achieving harmlessness and resource utilization. There is no wastewater discharge and little solid waste throughout the entire process. The process exhibits strong stability and adaptability: through pretreatment and parameter optimization, it can be adapted to arsenic-rich ash with different compositions, and the fluctuation range of arsenic removal rate and metal recovery rate is ≤2%, while the fluctuation range of existing technologies is usually ±10%. The product is of excellent quality: the purity of the recovered As2O3 is ≥99%, which meets the industrial first-class product standard; the copper grade in the metal matte can reach 40-60%, and the gold content in the gold concentrate can reach 100-300g / t, providing high-quality raw materials for subsequent refining.

[0022] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope as a result, and that the embodiments of the present invention include many changes, modifications and equivalents within the spirit and scope of the appended claims. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the method for comprehensive utilization of arsenic-rich ash from copper smelting according to the present invention. Detailed Implementation

[0024] Please refer to the instruction manual appendix. Figure 1 The present invention provides a technical solution: a method for comprehensive utilization of arsenic-rich ash from copper smelting.

[0025] The core innovation of this invention lies in constructing a multi-metal synergistic recovery technology system consisting of "low-temperature ripening arsenic removal—gradient condensation recovery—reduction smelting enrichment—wet separation and extraction." Through the organic coupling of each step, the following technical objectives are achieved: 1. Low-temperature curing selective arsenic removal: Utilizing the high selectivity of sulfuric acid to arsenic oxides at low temperatures, arsenic is converted into volatile As2O3 at 50-120℃, while metals such as copper, lead, and zinc are converted into stable sulfates, achieving the initial separation of arsenic from metals; the energy consumption of this process is only 30-40% of that of traditional high-temperature roasting, and the sintering deactivation of metal oxides is avoided.

[0026] 2. Gradient condensation for high-value recovery: By controlling the temperature gradient in two stages (first stage 100-150℃, second stage 50-90℃), the difference in saturated vapor pressure between As2O3 and other impurities (such as SO3, dust) is utilized to achieve efficient separation and purification of As2O3, with a product purity of over 99%.

[0027] 3. Reduction smelting three-phase separation: Under the action of carbonaceous reducing agent, metal sulfate is reduced to metal sulfide (matte phase), gold is enriched in the alloy phase due to chemical inertness, and zinc enters the slag phase, realizing the separation of slag-matte-gold three phases in one step, and the metal recovery rate is significantly improved.

[0028] 4. Wet selective leaching: By utilizing the differences in metal activity and controlling the concentration of sulfuric acid and oxidation potential, copper, zinc and lead in the matte phase can be separated, avoiding the repeated acid-base adjustments of traditional processes and reducing reagent consumption by more than 50%.

[0029] Detailed process description of each step in this invention: Step (1): Pretreatment of arsenic-rich ash; The purpose of this step is to remove physical impurities and control the particle size of the raw materials to ensure the uniformity of subsequent chemical reactions; the specific operation is as follows: The raw arsenic-rich ash was dry-screened using a vibrating screen with a screen aperture of 5mm. During the screening process, a cyclone dust collector was used to collect fine particles to prevent dust from escaping. The pretreated arsenic-rich ash obtained after screening should meet the following requirements: Particle size distribution: 0.1-5mm, of which ≥60% are 0.5-2mm particles; Moisture content: Controlled to ≤5wt%. If the moisture content of the raw material is too high, it needs to be dried in a rotary dryer at 150-200℃ for 30-60 minutes. Impurity content: Remove mechanical impurities such as slag and refractory materials larger than 5mm to avoid wear on the reactor; The typical composition of the arsenic-rich ash is: As 10-30wt%, Cu 5-15wt%, Pb 3-10wt%, Zn 2-8wt%, Au 1-5g / t, with the balance being gangue components such as SiO2, CaO, and Al2O3. The composition of arsenic-rich ash produced by different smelting processes varies greatly. This invention can process raw materials with the above-mentioned full range of compositions by adaptively adjusting subsequent process parameters.

[0030] Step (2): Low-temperature sulfuric acid ripening This is the core arsenic removal step of the present invention, which uses a jacketed heated stirred reactor or a paddle-type ripening tank as the reaction equipment; the detailed process is as follows: Equipment configuration: The reactor is made of acid-resistant enamel or 316L stainless steel and is equipped with a variable frequency speed control stirring system (speed adjustable from 50-600r / min), a PT100 temperature sensor (accuracy ±1℃), an exhaust gas collection hood and an acid mist purification system.

[0031] Ingredient control: Sulfuric acid concentration: Adjusted according to the arsenic content in the arsenic-rich ash. When the As content is 10-20wt%, the sulfuric acid concentration is controlled at 15-25%; when the As content is 20-30wt%, the sulfuric acid concentration is controlled at 30-45%. The sulfuric acid is prepared by mixing concentrated sulfuric acid (98%) with production water in proportion. The preparation process requires continuous stirring and cooling, and the temperature is controlled at ≤60℃.

[0032] Liquid-to-solid ratio: 1:1-5:1 (mL:g), preferably 2:1-4:1. A liquid-to-solid ratio that is too low (<1:1) will result in viscous materials, difficulty in stirring, and incomplete reaction; a liquid-to-solid ratio that is too high (>5:1) will increase the cost of subsequent concentration.

[0033] Feeding method: Arsenic-rich ash is added to sulfuric acid solution at a uniform rate using a double spiral feeder. The feeding time is controlled at 10-15 minutes to avoid local overheating and clumping.

[0034] Reaction conditions: Temperature control: 50-120℃, preferably 60-110℃; when the temperature is below 50℃, the reaction rate is too slow (<0.5% / h); when the temperature is above 120℃, sulfuric acid will decompose too quickly, producing a large amount of SO3 flue gas, increasing the purification burden; jacketed steam or heat transfer oil heating is used, and the heating rate is controlled at 3-5℃ / min.

[0035] Stirring rate: 200-400 r / min, automatically adjusted according to the viscosity of the material; too low a speed will lead to uneven mass transfer and incomplete local reaction; too high a speed will increase energy consumption and equipment wear.

[0036] Reaction time: 1-5 hours, depending on arsenic content and temperature; the reaction endpoint is determined by online monitoring of As2O3 concentration in the exhaust gas. When the As2O3 concentration in the exhaust gas is <0.1 g / m³, the reaction is considered complete.

[0037] pH monitoring: During the reaction, the pH value gradually rises from -0.5 (strong acidity) to 0.5-1.0, which can be monitored in real time using a pH meter.

[0038] Product processing: After the reaction is completed, the molten material is in the form of slurry and is transported to a filter press for solid-liquid separation by a diaphragm pump; the filtrate (mainly containing sulfuric acid) is returned to the batching system for recycling, and the moisture content of the filter cake (molten material) is controlled at 15-25 wt% before proceeding to the next step of reduction smelting.

[0039] Step (3): As2O3 condensation and collection; This step employs a two-stage series condensation system to achieve efficient separation and purification of As2O3.

[0040] Flue gas purification: The flue gas generated by the curing reaction has a temperature of about 120-150℃. It first enters a cyclone dust collector to remove dust particles with a diameter >10μm, and then enters a bag filter (the filter bag material is PTFE, which is acid and temperature resistant) for fine dust removal to ensure that the dust content is ≤0.1g / m³; the dust removal efficiency must be ≥99.5% to avoid the co-condensation of dust and As2O3.

[0041] Primary condensation: A water-cooled shell-and-tube condenser is used, with cooling water temperature of 30-40℃ and flue gas outlet temperature controlled at 100-150℃. This stage mainly removes high-boiling-point components such as SO3 and H2SO4, with an As2O3 recovery rate of approximately 30-40%. The condensate is dilute sulfuric acid, which is returned to the aging step for reuse.

[0042] Secondary condensation: A finned tube condenser is used for refrigerant cooling. The refrigerant is an aqueous solution of ethylene glycol (concentration 30-50%), with a temperature ranging from -10 to 0℃, and the flue gas outlet temperature is controlled at 50-90℃. This stage is the main As2O3 collection section, with a collection rate of approximately 60-70%; the condensed As2O3 is a white crystalline powder.

[0043] Flue gas velocity: 0.5-2 m / s, preferably 0.8-1.5 m / s. Too high a velocity will lead to insufficient condensation and the escape of As2O3; too low a velocity will reduce the system's processing capacity.

[0044] Product processing: The As2O3 obtained from the secondary condensation is sent to a fluidized bed dryer via a screw conveyor and dried at 120-150℃ for 30 minutes to remove surface-adsorbed moisture and residual SO2, resulting in an As2O3 product with a purity ≥99%, which is then packaged and sold.

[0045] Step (4): Reduction smelting of the calcined material; The reduction smelting equipment is a medium-frequency induction furnace or a resistance furnace. The detailed process is as follows: Ingredients: The calcined material (moisture content 15-25wt%) and carbonaceous reducing agent (coke or anthracite, fixed carbon content ≥85%) are mixed at a mass ratio of 100:5-15; the amount of carbon is adjusted according to the metal sulfate content in the calcined material. The theoretical carbon consumption is calculated after the sulfate content is determined by the loss-in-weight method. The actual amount of carbon is 1.2-1.5 times the theoretical value.

[0046] Flux: SiO2 and CaO are mixed at a mass ratio of 1:0.5-2, and the amount added is 5-15% of the mass of the slag. The role of the flux is to adjust the pH of the slag to achieve the best separation effect of the slag shape; when the SiO2 / CaO ratio in the slag is 0.8-1.5, the slag viscosity is the lowest (about 0.5-2 Pa·s), and the separation effect of metal matte and slag is the best.

[0047] Smelting process: Heating rate: When heating from room temperature to 1000-1200℃, the heating rate should be controlled at 10-15℃ / min; Insulation temperature: 1000-1200℃, preferably 1050-1180℃. Too low a temperature (<1000℃) will lead to incomplete reduction reaction and low metal recovery rate; too high a temperature (>1200℃) will increase energy consumption and furnace lining erosion.

[0048] Incubation time: 2-4 hours, depending on the amount of material. Too short a time will result in incomplete reaction, while too long a time will increase energy consumption.

[0049] Atmosphere control: Nitrogen gas is introduced into the furnace for protection at a flow rate of 0.5-2 L / min to prevent metal oxidation.

[0050] Three-phase separation: After reduction smelting, three layers are formed inside the furnace: Upper slag: mainly contains ZnO, SiO2, and CaO, with a copper content ≤0.5wt%, which can be utilized as a resource; Intermediate metallic matte: mainly contains Cu₂S and PbS, with a copper content of 40-60%; Lower layer gold-rich material: gold content 100-300g / t; Three-phase separation is promoted by tilting the furnace or bottom blowing argon gas, and the phases are released separately after standing for 30-60 minutes.

[0051] Step (5): Extraction of valuable metals; Metal matte treatment: Selective oxidation leaching technology is used; the metal matte is crushed to a particle size of <2mm and leached in a mechanically stirred tank; specific parameters: ; Leaching agent: dilute sulfuric acid, concentration 5-20%, preferably 8-15%; Temperature: 60-80℃, heated by steam; Time: 1-3 hours, air or oxygen is introduced during the leaching process, and the oxidation potential is controlled at 300-500mV; pH control: pH is controlled between 1.5 and 2.5 via an automatic acid addition system; After leaching, liquid and solid separation occurred, and the filtrate contained Cu. 2+ Zn 2+ Copper and zinc are recovered through extraction-electrowinning or displacement methods; the filter residue mainly contains PbSO4, which is sent to the lead smelting system to recover lead.

[0052] Treatment of gold-containing concentrates: Pyrometallurgical smelting is carried out using a crucible furnace or medium-frequency furnace, with appropriate amounts of borax and soda added as fluxes, and smelting is carried out at 1200-1300℃ for 1-2 hours to obtain crude gold (gold content ≥90%), with a gold-silver alloy recovery rate ≥98%.

[0053] The process parameter optimization and system control of this invention: This invention employs a DCS (Distributed Control System) to achieve fully automated control of the entire process. Key control loops include: Temperature control: ripening reaction temperature ±2℃, melting temperature ±5℃; Ingredient accuracy: sulfuric acid flow rate accuracy ±0.5%, carbonaceous reducing agent weighing accuracy ±1%; Flue gas monitoring: Online As2O3 concentration monitoring, accuracy ±5%; Safety interlock: The emergency sprinkler system will be automatically activated when the concentration of As2O3 in the flue gas exceeds the standard (>1g / m³).

[0054] Detailed data of embodiments of the present invention: The technical effects and process stability of the present invention are verified through 16 specific embodiments below; all embodiments use the same process flow, and only the process parameters are adjusted according to the differences in raw material composition.

[0055] Example 1 1. Raw materials: Arsenic-rich ash composition: As 20wt%, Cu 10wt%, Pb 6wt%, Zn 4wt%, Au 3g / t; 2. Pretreatment: Sieving to remove impurities, particle size controlled at 0.1-5mm; 3. Low-temperature ripening: Liquid-to-solid ratio 2:1, 20% sulfuric acid, reaction at 70℃ and 300r / min for 2h; 4. Condensation collection: Level 1 120℃, Level 2 70℃, flow rate 1m / s; 5. Reduction smelting: Carbon ratio 100:8, flux (SiO2:CaO=1:1) 10%, smelting at 1100℃ with nitrogen 1L / min for 3 hours; 6. Results: Arsenic removal rate 98.2%, copper recovery rate 95.5%, lead recovery rate 95.2%, zinc recovery rate 95.0%, gold recovery rate 98.3%, and As2O3 purity 99.1%.

[0056] Example 2 1. Raw materials: As 15wt%, Cu 12wt%, Pb 8wt%, Zn 5wt%, Au 2g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: Liquid-to-solid ratio 3:1, 30% sulfuric acid, reaction at 80℃ and 250r / min for 3h; 4. Condensation collection: First stage 130℃, second stage 80℃, flow rate 1.2m / s; 5. Reduction smelting: Carbon ratio 100:10, flux (1:0.8) 12%, smelting at 1150℃ with nitrogen 1.5L / min for 3.5h; 6. Results: Arsenic removal rate 98.5%, copper recovery rate 96.1%, lead recovery rate 95.8%, zinc recovery rate 95.6%, gold recovery rate 98.5%, and As2O3 purity 99.2%.

[0057] Example 3 1. Raw materials: As 25wt%, Cu 8wt%, Pb 5wt%, Zn 3wt%, Au 4g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: liquid-to-solid ratio 2.5:1, 25% sulfuric acid, reaction at 90℃ and 350r / min for 2.5h; 4. Condensation collection: First stage 110℃, second stage 60℃, flow rate 0.8m / s; 5. Reduction smelting: Carbon ratio 100:7, flux (1:1.2) 8%, smelting at 1050℃ with nitrogen 0.8L / min for 2.5h; 6. Results: Arsenic removal rate 98.1%, copper recovery rate 95.3%, lead recovery rate 95.0%, zinc recovery rate 94.8%, gold recovery rate 98.2%, As2O3 purity 99.0%.

[0058] Example 4 1. Raw materials: As 30wt%, Cu 5wt%, Pb 3wt%, Zn 2wt%, Au 5g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature ripening: Liquid-to-solid ratio 4:1, 40% sulfuric acid, reaction at 100℃ and 400r / min for 4h; 4. Condensation collection: First stage 140℃, second stage 90℃, flow rate 1.5m / s; 5. Reduction smelting: Carbon ratio 100:12, flux (1:0.6) 15%, smelting at 1200℃ with nitrogen 2L / min for 4 hours; 6. Results: Arsenic removal rate 98.7%, copper recovery rate 95.0%, lead recovery rate 94.7%, zinc recovery rate 94.5%, gold recovery rate 98.6%, and As2O3 purity 99.3%.

[0059] Example 5 1. Raw materials: As 18wt%, Cu 15wt%, Pb 10wt%, Zn 8wt%, Au 1g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature ripening: Liquid-to-solid ratio 1:1, 10% sulfuric acid, 50℃, 200r / min reaction for 1h; 4. Condensation collection: First stage 100℃, second stage 50℃, flow rate 0.5m / s; 5. Reduction smelting: Carbon ratio 100:5, flux (1:2) 5%, smelting at 1000℃ with nitrogen 0.5L / min for 2 hours; 6. Results: Arsenic removal rate 98.0%, copper recovery rate 95.2%, lead recovery rate 95.1%, zinc recovery rate 95.0%, gold recovery rate 98.0%, and As2O3 purity 99.0%.

[0060] Example 6 1. Raw materials: As 22wt%, Cu 11wt%, Pb 7wt%, Zn 6wt%, Au 3.5g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: Liquid-to-solid ratio 5:1, 50% sulfuric acid, reaction at 120℃ and 300r / min for 5h; 4. Condensation collection: First stage 150℃, second stage 85℃, flow rate 2m / s; 5. Reduction smelting: Carbon ratio 100:15, flux (1:1.5) 14%, smelting at 1180℃ with nitrogen 1.8L / min for 3.8h; 6. Results: Arsenic removal rate 98.6%, copper recovery rate 96.0%, lead recovery rate 95.7%, zinc recovery rate 95.5%, gold recovery rate 98.4%, and As2O3 purity 99.2%.

[0061] Example 7 1. Raw materials: As 12wt%, Cu 13wt%, Pb 9wt%, Zn 7wt%, Au 2.5g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: Liquid-to-solid ratio 2:1, 15% sulfuric acid, reaction at 60℃ and 280r / min for 2h; 4. Condensation collection: First stage 115℃, second stage 65℃, flow rate 0.9m / s; 5. Reduction smelting: Carbon ratio 100:9, flux (1:0.7) 9%, smelting at 1080℃ with nitrogen 1.2L / min for 2.8h; 6. Results: Arsenic removal rate 98.3%, copper recovery rate 95.8%, lead recovery rate 95.4%, zinc recovery rate 95.2%, gold recovery rate 98.2%, and As2O3 purity 99.1%.

[0062] Example 8 1. Raw materials: As 28wt%, Cu 7wt%, Pb 4wt%, Zn 3.5wt%, Au 4.5g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: liquid-to-solid ratio 3.5:1, 35% sulfuric acid, reaction at 95℃ and 380r / min for 3.5h; 4. Condensation collection: First stage 135℃, second stage 75℃, flow rate 1.6m / s; 5. Reduction smelting: Carbon ratio 100:11, flux (1:1.3) 11%, smelting at 1120℃ with nitrogen 1.6L / min for 3.2h; 6. Results: Arsenic removal rate 98.4%, copper recovery rate 95.4%, lead recovery rate 95.0%, zinc recovery rate 94.9%, gold recovery rate 98.5%, and As2O3 purity 99.2%.

[0063] Example 9 1. Raw materials: As 16wt%, Cu 9wt%, Pb 6.5wt%, Zn 4.5wt%, Au 3g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature ripening: Liquid-to-solid ratio 3:1, 22% sulfuric acid, reaction at 75℃ and 320r / min for 2.2h; 4. Condensation collection: First stage 125℃, second stage 72℃, flow rate 1.1m / s; 5. Reduction smelting: Carbon ratio 100:8, flux (1:1) 10%, smelting at 1130℃ with nitrogen 1.3L / min for 3.1h; 6. Results: Arsenic removal rate 98.3%, copper recovery rate 95.6%, lead recovery rate 95.3%, zinc recovery rate 95.1%, gold recovery rate 98.3%, and As2O3 purity 99.1%.

[0064] Example 10 1. Raw materials: As 19wt%, Cu 14wt%, Pb 8.5wt%, Zn 5.5wt%, Au 2.2g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: liquid-to-solid ratio 4.5:1, 38% sulfuric acid, reaction at 110℃ and 360r / min for 4.5h; 4. Condensation collection: Level 1 145℃, Level 2 88℃, flow rate 1.7m / s; 5. Reduction smelting: Carbon ratio 100:13, flux (1:1.8) 13%, smelting at 1160℃ with nitrogen 1.6L / min for 3.6h; 6. Results: Arsenic removal rate 98.7%, copper recovery rate 96.2%, lead recovery rate 95.9%, zinc recovery rate 95.7%, gold recovery rate 98.6%, and As2O3 purity 99.3%.

[0065] Example 11 1. Raw materials: As 24wt%, Cu 6wt%, Pb 4.5wt%, Zn 3.2wt%, Au 4.2g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature ripening: Liquid-to-solid ratio 2.8:1, 28% sulfuric acid, reaction at 85℃ and 290 r / min for 3.2 h. 4. Condensation collection: First stage 105℃, second stage 55℃, flow rate 0.7m / s; 5. Reduction smelting: Carbon ratio 100:6, flux (1:1.1) 7%, smelting at 1070℃ with nitrogen 0.9L / min for 2.6h; 6. Results: Arsenic removal rate 98.2%, copper recovery rate 95.1%, lead recovery rate 94.9%, zinc recovery rate 94.7%, gold recovery rate 98.1%, As2O3 purity 99.0%.

[0066] Example 12 1. Raw materials: As 26wt%, Cu 10wt%, Pb 6wt%, Zn 4.8wt%, Au 3.8g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: liquid-to-solid ratio 3.2:1, 32% sulfuric acid, reaction at 92℃ and 340r / min for 3h; 4. Condensation collection: First stage 128℃, second stage 78℃, flow rate 1.3m / s; 5. Reduction smelting: Carbon ratio 100:11, flux (1:0.9) 11%, smelting at 1130℃ with nitrogen 1.4L / min for 3.2h; 6. Results: Arsenic removal rate 98.5%, copper recovery rate 95.8%, lead recovery rate 95.5%, zinc recovery rate 95.3%, gold recovery rate 98.4%, and As2O3 purity 99.2%.

[0067] Example 13 1. Raw materials: As 14wt%, Cu 9.5wt%, Pb 7.5wt%, Zn 6.2wt%, Au 1.8g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: liquid-to-solid ratio 1.5:1, 18% sulfuric acid, reaction at 65℃ and 270 r / min for 2.8 h; 4. Condensation collection: First stage 112℃, second stage 62℃, flow rate 0.85m / s; 5. Reduction smelting: Carbon ratio 100:7.5, flux (1:0.6) 8.5%, smelting at 1090℃ with nitrogen 1.1L / min for 2.9h; 6. Results: Arsenic removal rate 98.1%, copper recovery rate 95.4%, lead recovery rate 95.2%, zinc recovery rate 95.0%, gold recovery rate 98.2%, As₂O₃ purity 99.0%;

[0068] Example 14 1. Raw materials: As 21wt%, Cu 12.5wt%, Pb 9.2wt%, Zn 7.8wt%, Au 3.3g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: liquid-to-solid ratio 3.8:1, 33% sulfuric acid, reaction at 98℃ and 370r / min for 3.8h; 4. Condensation collection: First stage 138℃, second stage 82℃, flow rate 1.4m / s; 5. Reduction smelting: Carbon ratio 100:12.5, flux (1:1.4) 14.5%, smelting at 1170℃ with nitrogen 1.9L / min for 3.7h; 6. Results: Arsenic removal rate 98.6%, copper recovery rate 96.3%, lead recovery rate 96.0%, zinc recovery rate 95.8%, gold recovery rate 98.5%, and As2O3 purity 99.3%.

[0069] Example 15 1. Raw materials: As 27wt%, Cu 7.5wt%, Pb 5.2wt%, Zn 3.6wt%, Au 4.7g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature ripening: liquid-to-solid ratio 2.3:1, 24% sulfuric acid, reaction at 78℃ and 310 r / min for 2.3 h; 4. Condensation collection: First stage 108℃, second stage 58℃, flow rate 0.6m / s; 5. Reduction smelting: Carbon ratio 100:8.5, flux (1:1.3) 9.5%, smelting at 1060℃ with nitrogen 0.7L / min for 2.4h; 6. Results: Arsenic removal rate 98.3%, copper recovery rate 95.2%, lead recovery rate 95.0%, zinc recovery rate 94.8%, gold recovery rate 98.4%, and As2O3 purity 99.1%.

[0070] Example 16 1. Raw materials: As 23wt%, Cu 11.5wt%, Pb 7.2wt%, Zn 5.8wt%, Au 3.1g / t; 2. Pretreatment: Same as in Example 1; 3. Low-temperature curing: liquid-to-solid ratio 4.2:1, 36% sulfuric acid, reaction at 105℃ and 390r / min for 4.2h; 4. Condensation collection: Level 1 142℃, Level 2 85℃, flow rate 1.8m / s; 5. Reduction smelting: Carbon ratio 100:14, flux (1:1.6) 12.5%, smelting at 1190℃ with nitrogen 1.7L / min for 3.9h; 6. Results: Arsenic removal rate 98.8%, copper recovery rate 96.4%, lead recovery rate 96.1%, zinc recovery rate 95.9%, gold recovery rate 98.7%, and As2O3 purity 99.4%.

[0071] V. Correlation Analysis between Process Parameters and Effects Regression analysis of data from 16 examples revealed the following patterns: 1. Sulfuric acid concentration and arsenic removal rate: In the range of 10-40%, the arsenic removal rate is positively correlated with the concentration (R²=0.85); when the concentration is >40%, the improvement effect is not obvious and the risk of equipment corrosion increases.

[0072] 2. Reaction temperature and rate: The reaction rate increases by about 1.5 times for every 10°C increase in temperature, but the decomposition rate of sulfuric acid accelerates at temperatures above 120°C, leading to an increase in harmful gases.

[0073] 3. Carbon ratio and metal recovery rate: Increasing the carbon ratio from 100:5 to 100:10 significantly improves the metal recovery rate; further increasing it to 100:15 results in limited improvement in recovery rate but increases energy consumption. Therefore, the optimal carbon ratio is 100:8-12.

[0074] VI. Industrialized Production Configuration For an industrial production line with an annual processing capacity of 10,000 tons of arsenic-rich ash, the following configuration is recommended: Pretreatment: 2 YA1536 vibrating screens (processing capacity 5t / h); Low-temperature curing: 3 20m³ glass-lined reactors (2 in use, 1 on standby); Condensation system: Ф1200mm water-cooled tower + Ф800mm refrigerant condenser; Reduction smelting: 2 x 3t medium-frequency induction furnaces; Leaching system: 4 x 5m³ mechanical stirring tanks; Control system: Siemens S7-300DCS system.

Claims

1. A method for comprehensive utilization of arsenic-rich ash from copper smelting, characterized in that, include: S1, Arsenic-rich ash pretreatment: The arsenic-rich ash from copper smelting is screened to remove impurities with a particle size >5mm, resulting in pretreated arsenic-rich ash; S2, Low-temperature sulfuric acid curing: Pretreated arsenic-rich ash is mixed with sulfuric acid solution at a liquid-solid ratio of 1:1-5:1 and stirred at 50-120℃ for 1-5 hours. The mass concentration of sulfuric acid solution is controlled at 10-50% to obtain cured material and flue gas containing As2O3. S3, As2O3 condensation and collection: The flue gas containing As2O3 generated by S2 is introduced into a multi-stage condensation system after dust removal. The first-stage condensation temperature is controlled at 100-150℃, the second-stage condensation temperature at 50-90℃, and the flue gas velocity at 0.5-2m / s. As2O3 product is collected. S4, Reduction Smelting of Cemented Material: The chopped material obtained in S2 is mixed with carbonaceous reducing agent at a mass ratio of 100:5-15, flux is added to adjust the slag shape, and reduction smelting is carried out at 1000-1200℃ for 2-4 hours to achieve the separation of slag-matte-gold three phases and obtain smelting slag, metallic matte and gold-containing enrichment. S5, Valuable Metal Extraction: Subsequent hydrometallurgical or pyrometallurgical processes are performed on the matte and gold-bearing concentrates in S4 to recover valuable metals such as copper, lead, zinc, and gold.

2. The method for comprehensive utilization of arsenic-rich ash from copper smelting according to claim 1, characterized in that: In S1, the composition of the arsenic-rich ash is: As 10-30wt%, Cu 5-15wt%, Pb 3-10wt%, Zn 2-8wt%, Au 1-5g / t, and the particle size is controlled at 0.1-5mm after sieving.

3. The method for comprehensive utilization of arsenic-rich ash from copper smelting according to claim 1, characterized in that: In S2, the sulfuric acid solution has a mass concentration of 15-45% and a stirring rate of 200-400 r / min.

4. The method for comprehensive utilization of arsenic-rich ash from copper smelting according to claim 1, characterized in that: In S3, the multi-stage condensation system includes a primary condensation tower and a secondary condensation tower. The primary condensation tower is cooled by water, and the secondary condensation tower is cooled by refrigerant. The dust content of the flue gas after dust removal is ≤0.1g / m³.

5. The method for comprehensive utilization of arsenic-rich ash from copper smelting according to claim 1, characterized in that: In S4, the carbonaceous reducing agent is coke or anthracite with a fixed carbon content ≥85%; The flux is a mixture of SiO2 and CaO in a mass ratio of 1:0.6-1.8, and the amount of flux added is 6-14% of the mass of the calcined material.

6. The method for comprehensive utilization of arsenic-rich ash from copper smelting according to claim 1, characterized in that: In S4, nitrogen gas is introduced into the furnace for protection during reduction smelting, with a nitrogen flow rate of 0.7-1.8 L / min.

7. The method for comprehensive utilization of arsenic-rich ash from copper smelting according to claim 1, characterized in that: In S5, the metal matte is subjected to selective oxidation leaching treatment, with sulfuric acid solution as the leaching agent. The leaching temperature is controlled at 60-80℃, the sulfuric acid concentration at 5-20%, and the leaching time at 1-3 hours to achieve the separation of copper, zinc, and lead.

8. The method for comprehensive utilization of arsenic-rich ash from copper smelting according to claim 1, characterized in that: The low-temperature sulfuric acid ripening reaction is carried out in a glass-lined reactor or a 316L stainless steel reactor; the reduction smelting is carried out in a medium-frequency induction furnace or a resistance furnace.

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