A method for co-processing gold smelting and non-ferrous smelting waste

Abstract

The application discloses a method for treating gold smelting and non-ferrous smelting waste in cooperation, and relates to the field of non-ferrous metal smelting. The method mixes and melts complex gold concentrate with calcium sulfate residue, mineralization transformation residue, copper concentrate and slag concentrate to produce low-grade copper matte, and the low-grade copper matte is subjected to blowing, anode refining, electrolytic refining and precious metal recovery to comprehensively recover and utilize valuable elements such as gold, silver, copper, lead, arsenic and sulfur in the gold concentrate and non-ferrous smelting waste. The method has the characteristics of high gold and silver recovery rate and environmental friendliness, is simple to operate and has good economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, and specifically relates to a method for the co-processing of waste from gold smelting and non-ferrous metal smelting. Background Technology

[0002] The main methods for gold extraction include cyanidation, amalgamation, and gravity separation. Amalgamation is mainly used in small mines and artisanal mining. Due to the high toxicity of mercury and the health risks associated with long-term exposure, and because mercury is difficult to recover and tends to remain in the environment, some countries have banned its use. Gravity separation requires a large amount of water and is not effective at recovering fine-grained gold, resulting in a low recovery rate. Cyanidation is highly efficient, but for complex carbon- and sulfur-containing gold concentrates, pretreatment (such as high-temperature roasting) is required to avoid affecting its effectiveness. Cyanide is highly toxic, and any leakage poses a significant threat to the environment and organisms. Furthermore, cyanidation produces a large amount of cyanide tailings, occupying a significant amount of land and polluting the environment. Nevertheless, this method remains the most important method for gold extraction.

[0003] Non-ferrous metal smelters generate some non-ferrous smelting waste during the production process, such as calcium sulfate slag and mineralization transformation slag. Since these non-ferrous smelting wastes contain small amounts of heavy metals such as copper, lead, and arsenic, if these heavy metals are not effectively utilized, it will lead to the waste of mineral resources and environmental pollution.

[0004] Therefore, the clean and efficient processing of complex gold concentrates, along with the coordinated processing of smelting waste from non-ferrous metal smelters, to achieve comprehensive recovery of elements such as gold, silver, copper, and arsenic from complex gold concentrates and non-ferrous smelting wastes, will greatly promote the improvement of my country's smelting technology. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for the co-processing of gold smelting and non-ferrous smelting waste. This method involves blending complex gold concentrate with calcium sulfate slag, mineralization transformation slag, copper concentrate, and slag concentrate, and then smelting to produce low-grade copper matte. The low-grade copper matte is then subjected to processes such as blowing, anode refining, electrolytic refining, and precious metal recovery to achieve comprehensive recovery and utilization of valuable metals such as gold, silver, copper, and arsenic from both the gold concentrate and the non-ferrous smelting waste.

[0006] The technical solution of this invention is implemented as follows: a method for co-processing waste from gold smelting and non-ferrous smelting, comprising the following process steps: (1) Blending: Complex gold concentrate, calcium sulfate slag, mineralization transformation slag, copper concentrate, and slag concentrate are blended in a mass ratio of 30~35:0~5:0~5:30~35:20~30 to form a mixed ore; (2) Smelting: The mixed ore is fed into a smelting furnace for smelting at a temperature of 1200~1300℃, and the oxygen volume to the mass ratio of the mixed ore is 180~220 Nm. 3 The smelting time is 1.5h~2.5h, and the desulfurization rate is 30%~70%. The gas injected into the oxygen lance during the smelting process can be oxygen-enriched air (oxygen volume content: 60~80%) or pure oxygen. The flue gas produced by smelting is sent to the acid production system after passing through the dust collection system. The smelting slag produced by smelting is sent to the mineral processing system. The slag concentrate produced is returned to the batching. The low-grade copper matte produced by smelting is sent to the blowing process. During the smelting process, As in the mineralization transformation slag is oxidized to As2O3 and enters the smelting flue gas, which is collected by the arsenic collection device to obtain arsenic trioxide dust. S in the mineralization transformation slag provides heat for the smelting reaction during the smelting process and maintains the thermal balance of the furnace. At the same time, some S is oxidized to SO2 and enters the smelting flue gas to enter the acid production system to obtain sulfuric acid products. Some S participates in the synthesis of copper matte, so that gold, silver and other precious metals in the slag enter the matte and are further enriched in the subsequent blowing and refining processes. (3) The low-grade copper matte produced by smelting is successively sent to processes such as blowing, anode refining, electrolytic refining, and precious metal recycling to recover elements such as gold, silver, and copper; Preferably, the calcium sulfate slag mentioned in step one is the neutralized calcium slag produced by neutralizing the acidic wastewater from non-ferrous metal smelting purification process, wherein the moisture content is ≤25%, the Ca content is 18%≤Ca≤22%, the Au content is ~3g / t, and the Ag content is ~100 g / t. The mineralization transformation slag is the slag produced by mineralization transformation of the hydrous arsenic sulfide slag produced during the non-ferrous metal smelting process, wherein the moisture content is ≤15%, the S content is 30%≤S≤45%, the As content is 30%≤As≤45%, and the Au content is ~2g / t, and the Ag content is ~50 g / t. Preferably, the mixed ore described in step one has a controlled moisture content of ≤10%, an FeO / SiO2 mass ratio of 1.6~2.0, a CaO / SiO2 mass ratio of 0.2~0.4, an available sulfur content of 22~30%, an As content of 1.0%~3.5%, an Au content of ≥10g / t, an Ag content of ≥300g / t, a Cu content of 6%~10%, and a SiO2 content of 10%~15%. Preferably, in the ore blending process described in step one, lump coal is added via an auxiliary material conveyor belt, which facilitates real-time adjustment of the viscosity of the smelting slag. The amount of lump coal added is 0.1~1.5‰ of the mixed ore. During the smelting process, calcium sulfate slag is easily decomposed into CaO and SO2 when coal is involved. The generated CaO reacts with gangue in the mixed ore to form slag, and the generated SO2 enters the acid production system with the flue gas to produce acid, thereby realizing the substitution of limestone and the recovery of sulfur from calcium sulfate slag. Preferably, in the copper matte produced during the smelting process described in step two, the copper grade is 35%~50%, Au≥50g / t, Ag≥1500g / t, and the copper grade in the smelting slag produced is 1%~4%, Au<4g / t, Ag<150g / t, the FeO / SiO2 mass ratio is 1.4~1.8, and the CaO / SiO2 mass ratio is 0.2~0.4. Preferably, in the complex gold concentrate described in step one, gold existing in the form of elemental form and silver existing in the form of sulfides, during the process of mixing and smelting with calcium sulfate slag, mineralization transformation slag, and copper concentrate, low-grade copper matte formed by elements such as copper, iron, lead, silver, and sulfur, when in contact with elemental gold, gold is first adsorbed onto the surface of the copper matte and then diffuses into the interior of the copper matte, thereby achieving efficient capture of gold from the gold concentrate by the copper matte; Preferably, during the arsenic recovery process, the arsenic content of the inlet flue gas is ≥15g / m³. 3 Arsenic content in the flue gas at the outlet is ≤0.1g / m³. 3 Arsenic trioxide (As2O3) content in the dust is ≥85%; Metals such as copper, lead, zinc, silver, and arsenic contained in gold concentrate and non-ferrous smelting waste are separated during the smelting process. Copper and silver enter the copper matte, while lead, zinc, and arsenic enter the flue gas. By controlling the different condensation temperatures of lead and zinc oxides and arsenic oxides (e.g., zinc oxide volatilization temperature above 1000℃, lead oxide volatilization temperature 400~950℃, and arsenic oxide volatilization temperature 200~600℃), coarse separation of lead, zinc, and arsenic is achieved. During flue gas treatment, arsenic is recovered through a rapid cooling process. The rapid cooling tower inlet temperature is above 330℃, the outlet temperature is 150℃, the cooling rate is 20℃ / s, and the absorbent is water or alkaline solution to achieve arsenic enrichment. The copper matte is then used for processes such as blowing, anode refining, electrolytic refining, and precious metal recovery to recover gold, silver, and copper from the gold concentrate.

[0007] The main mechanism involved in this invention is as follows: In complex gold concentrates, gold exists in elemental form, while silver exists mostly in the form of sulfides. During the blending and smelting process with calcium sulfate slag, mineralization transformation slag, and copper concentrate, elements such as copper, iron, lead, silver, and sulfur will form low-grade copper matte. When low-grade copper matte comes into contact with elemental gold, the gold is first adsorbed onto the surface of the copper matte and then diffuses into the interior of the copper matte, thereby achieving efficient capture of gold from the gold concentrate by the copper matte.

[0008] Gold concentrate and non-ferrous smelting waste also contain metallic elements such as copper, lead, zinc, silver, and arsenic. During the smelting process, copper and silver enter the copper matte, while lead, zinc, and arsenic enter the flue gas. By controlling the different condensation temperatures of lead and zinc oxides and arsenic oxides, coarse separation of lead and zinc elements from arsenic is achieved. Arsenic is mainly concentrated in the latter half of the flue gas treatment process, where it is enriched through a rapid cooling arsenic recovery process. The copper matte then undergoes processes such as blowing, anode refining, electrolytic refining, and precious metal recovery to recover gold, silver, copper, and other elements from the gold concentrate.

[0009] During the ore blending process, calcium sulfate slag and mineralization transformation slag produced in non-ferrous smelting are added. During smelting, the calcium sulfate slag is easily decomposed into CaO and SO2 at 1200℃ with the participation of coal. The generated CaO reacts with gangue in the mixed ore to form slag, and the generated SO2 enters the acid production system with the flue gas to produce acid, thereby realizing the substitution of limestone and the recovery of sulfur from the calcium sulfate slag. During the smelting process, As in the mineralization transformation slag is oxidized to As2O3 and enters the smelting flue gas, where it is collected by the arsenic recovery device to obtain arsenic trioxide dust. The S in the mineralization transformation slag provides heat for the smelting reaction during the smelting process, maintaining the thermal balance of the furnace. Part of it is oxidized to SO2 and enters the smelting flue gas to enter the acid production system to obtain sulfuric acid products, while part of it participates in the synthesis of copper matte, allowing precious metals such as gold and silver in the slag to enter the matte. In the subsequent blowing and refining processes, it is further enriched, thereby realizing the substitution of pyrite during the smelting process and the recovery of valuable elements such as gold, silver, arsenic, and sulfur from the mineralization transformation slag.

[0010] The beneficial effects of this invention are: (1) This process has the advantage of higher gold and silver recovery rates compared to traditional gold extraction processes. Compared to traditional wet gold extraction processes, the gold and silver recovery rates are 3-8 percentage points and 10-20 percentage points higher, respectively.

[0011] (2) This process is more environmentally friendly than the traditional gold extraction process. No large amount of wastewater and cyanide tailings are generated during the production process, and the tailings produced can be used as raw materials for cement plants.

[0012] (3) This process has a high level of resource utilization and can comprehensively recover valuable elements such as gold, silver, copper, lead, zinc, sulfur, and arsenic from gold concentrate and non-ferrous smelting waste. It can realize the large-scale treatment of complex gold concentrate and non-ferrous smelting waste, achieve efficient enrichment and recovery of arsenic, and solve the problem of arsenic-containing hazardous waste disposal.

[0013] (4) This process can effectively treat the calcium sulfate slag and mineralization transformation slag produced by the wastewater treatment station of the smelter, and realize the substitution of limestone and pyrite and the recovery of sulfur and arsenic elements.

[0014] (5) This process is simple to operate, has a high level of automation, is easy to implement, and has a low production cost. Attached Figure Description

[0015] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0016] To better understand and implement this invention, the following description, in conjunction with the accompanying drawings, further illustrates the invention: Example 1: Ore blending: Complex gold concentrate, calcium sulfate slag, mineralization transformation slag, copper concentrate, and slag concentrate are blended in a ratio of 30:1:3:35:30 to form a mixed ore. The amount of lump coal added is 1‰ of the mixed ore. The lump coal is added through an auxiliary material conveyor belt to facilitate real-time adjustment of the viscosity of the smelting slag.

[0017] The composition of calcium sulfate slag, mineralization transformation slag, and mixed ore is shown in the table below: Calcium sulfate residue composition Calcium sulfate residue 22.4 0.3 54.27 21.84 12.42 0.81 0.49 0.09 0.62 0.24 Mineralization transformation slag composition Mineralized Transformation Slag 14.23 0.2 32.4 38.57 43.38 0.23 2.47 Mixed mineral composition Mixed ore 9.84 15.02 1107 7.52 24.23 2.47 2.23 22.56 13.82 3.03 The above-mentioned mixed ore was fed into the molten pool furnace via a conveyor belt for smelting. The rate of mixed ore addition was 106 t / h, the smelting temperature was controlled at 1250℃, and the oxygen-to-material ratio was controlled at 204 Nm. 3 After reacting for 2 hours, slag and copper matte are discharged, and arsenic is collected. During arsenic collection, the arsenic content at the inlet of the quench tower is controlled at 17.1 g / m³, and the arsenic content at the outlet of the arsenic collection bag filter is controlled at 0.03 g / m³. The flue gas produced by smelting is sent to acid production after passing through the dust collection system. The smelting slag is sent to the mineral processing system, and the slag concentrate is returned to the batching process. The low-grade copper matte produced by smelting is sequentially sent to processes such as blowing, anode refining, electrolytic refining, and precious metal recovery to recover elements such as gold, silver, and copper.

[0018] Sampling and testing were conducted during the slag discharge, copper matte discharge, and arsenic collection processes. The test results for the smelting slag, copper matte, and arsenic trioxide dust are as follows: Smelting slag composition Smelting slag 3.2 185.3 2.52 37.21 1.37 0.83 26.39 5.82 Low-grade copper matte composition Low-grade copper matte 102.1 5881 37.6 19.84 3.47 0.76 30.15 Arsenic trioxide dust components Arsenic trioxide dust 88.44 2.85 0.35 0.66 Example

[0019] Ore blending: Complex gold concentrate, calcium sulfate slag, mineralization transformation slag, copper concentrate, and slag concentrate are blended in a ratio of 32:2:4:32:25 to form a mixed ore. The amount of lump coal added is 1.2‰ of the mixed ore. The lump coal is added through an auxiliary material conveyor belt to facilitate real-time adjustment of the viscosity of the smelting slag.

[0020] The composition of calcium sulfate slag, mineralization transformation slag, and mixed ore is shown in the table below: Calcium sulfate residue composition Calcium sulfate residue 23.6 0.2 32.56 21.33 10.72 0.77 0.24 0.11 0.43 0.16 Mineralization transformation slag composition Mineralized Transformation Slag 13.85 0.2 25.7 35.84 40.25 0.27 3.52 Mixed mineral composition Mixed ore 8.42 20.5 1083 7.86 25.23 1.98 2.57 24.56 15.76 3.44 The above-mentioned mixed ore was fed into the molten pool furnace via a conveyor belt for smelting. The rate of mixed ore addition was 98 t / h, the smelting temperature was controlled at 1270℃, and the oxygen-to-material ratio was controlled at 210 Nm. 3 After reacting for 2 hours, slag and copper matte are discharged, and arsenic is collected. During arsenic collection, the arsenic content at the inlet of the quench tower is controlled at 16.8 g / m³, and the arsenic content at the outlet of the arsenic collection bag filter is controlled at 0.05 g / m³. The flue gas produced by smelting is sent to acid production after passing through the dust collection system. The smelting slag is sent to the mineral processing system, and the slag concentrate is returned to the batching process. The low-grade copper matte produced by smelting is sequentially sent to processes such as blowing, anode refining, electrolytic refining, and precious metal recovery to recover elements such as gold, silver, and copper.

[0021] Sampling and testing were conducted during the slag discharge, copper matte discharge, and arsenic collection processes. The test results for the smelting slag, arsenic trioxide dust, and copper matte are as follows: Smelting slag composition Smelting slag 3.34 176.5 2.64 38.98 1.12 0.96 27.52 5.79 Low-grade copper matte composition Low-grade copper matte 125.4 5753 38.3 18.84 3.07 0.86 31.15 Arsenic trioxide dust components Arsenic trioxide dust 87.44 2.64 0.22 0.43

Claims

1. A method for the co-processing of waste from gold smelting and non-ferrous smelting, characterized in that... The process includes the following steps: (1) Ore blending: Complex gold concentrate, calcium sulfate slag, mineralization transformation slag, copper concentrate, and slag concentrate are blended in a mass ratio of 30~35:0~5:0~5:30~35:20~30 to form a mixed ore; the calcium sulfate slag is neutralized calcium slag produced by neutralizing the acidic lime produced during the purification of non-ferrous metal smelting, wherein the moisture content is ≤25%, the calcium content is 18%≤Ca≤22%, the argon content is 0.2~3g / t, and the argon content is 32.56~100 g / t; the mineralization transformation slag is slag produced by mineralization transformation of the hydrated arsenic sulfide slag produced during the non-ferrous metal smelting process, wherein the moisture content is ≤15%, the sulfur content is 30%≤S≤45%, the as content is 30%≤As≤45%, the argon content is 0.2~2g / t, and the argon content is 25.7~50g / t. g / t; the mixed ore is controlled to have a moisture content ≤10%, an FeO / SiO2 mass ratio of 1.6~2.0, a CaO / SiO2 mass ratio of 0.2~0.4, an effective sulfur content of 22~30%, an As content of 1.0%~3.5%, an Au content ≥10g / t, an Ag content ≥300g / t, a Cu content of 6%~10%, and a SiO2 content of 10%~15%; during the ore blending process, lump coal is added via an auxiliary material conveyor belt, and the amount of lump coal added is 0.1~1.5‰ of the mixed ore; (2) Smelting: The mixed ore is fed into a smelting furnace for smelting at a temperature of 1200~1300℃, and the oxygen volume to the mass ratio of the mixed ore is 180~220 Nm³. 3 The smelting time is 1.5h~2.5h, the desulfurization rate is 30%~70%, the flue gas produced by smelting is sent to the acid production system after passing through the dust collection system, the smelting slag produced by smelting is sent to the mineral processing system, the slag concentrate produced by smelting is returned to the batching process, and the low-grade copper matte produced by smelting is sent to the blowing process; the copper grade in the copper matte produced by smelting is 35%~50%, Au≥50g / t, Ag≥1500g / t, the copper grade in the smelting slag produced by smelting is 1%~4%, Au<4g / t, Ag<150g / t, the FeO / SiO2 mass ratio is 1.4~1.8, and the CaO / SiO2 mass ratio is 0.2~0.4; when collecting arsenic from the flue gas, the arsenic content of the inlet flue gas is ≥15g / m³. 3 Arsenic content in the flue gas at the outlet is ≤0.1g / m³. 3 Arsenic trioxide (As2O3) content in the dust is ≥85%; (3) The low-grade copper matte produced by smelting is successively sent to the blowing, anode refining, electrolytic refining and precious metal recycling processes to recover the gold, silver and copper elements.

2. The method for co-processing waste from gold smelting and non-ferrous smelting as described in claim 1, characterized in that... In the complex gold concentrate described in step one, gold existing in elemental form and silver existing in sulfide form are mixed and smelted with calcium sulfate slag, mineralization transformation slag, and copper concentrate. During this process, low-grade copper matte formed by elements such as copper, iron, lead, silver, and sulfur comes into contact with elemental gold. The gold is first adsorbed onto the surface of the copper matte and then diffuses into the interior of the copper matte, thereby achieving efficient capture of gold from the gold concentrate by the copper matte.

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