Method for synergistically high-value resource utilization of gold smelting acid sludge and zinc oxide fume

Abstract

This invention relates to a method for the synergistic high-value resource utilization of acid sludge from gold smelting and zinc oxide dust, belonging to the field of solid waste resource utilization. The method comprises 12 steps: alkaline washing and dechlorination, pulping, oxidative roasting, reduction ripening, chlorination roasting, neutral leaching, high-acid leaching, pre-neutralization, tannin precipitation of germanium, neutralization precipitation of iron, high-pressure ripening, and purification electrowinning. First, alkaline washing removes Cl from the dust, reducing the burden on electrowinning. After the dechlorination solution is mixed with the acid sludge from gold smelting, low-temperature microwave roasting removes selenium, followed by high-temperature chlorination to volatilize silver. A portion of the remaining iron oxide is used as an oxidant to enhance the leaching of ZnS from the dust, and another portion is used as a seed crystal to enhance the precipitation of iron in the hematite method. The dust undergoes neutral leaching followed by high-acid oxidative leaching. Under conditions of efficient germanium leaching, Ge is concentrated in the second-stage leachate, reducing tannic acid consumption. Using this invention, the direct recovery rate of selenium in acidic sludge during gold smelting reaches 96.00%; the direct recovery rate of germanium in flue dust reaches 97.16%; the direct recovery rate of zinc reaches 97.41%; and the consumption of tannic acid is reduced by 15 times.

Description

Technical Field

[0001] This invention relates to a method for the synergistic high-value resource utilization of acid sludge from gold smelting and zinc oxide dust, belonging to the field of solid waste resource utilization. Background Technology

[0002] Sludge from gold smelting is solid waste generated by acid production systems. It contains metals such as selenium, silver, and iron. Most companies use methods such as sulfation roasting and wet leaching, which can only achieve high-value utilization of some metals. After treatment, the sludge is still industrial solid waste.

[0003] Zinc oxide dust is a volatilization product of zinc roasted sand leaching residue, containing elements such as chlorine, zinc, and germanium. Zinc and germanium are typically extracted using a two-stage acid leaching process: tannin precipitation of germanium, neutralization and iron precipitation, zinc powder purification, and electrowinning. However, after a period of time, chlorine accumulates in the system, causing consumption of the anode lead plate and reducing the quality of the zinc plate. Both acid leaching stages have high acid concentrations, resulting in dispersion of zinc and germanium in the leachate, and tannin consumption reaching 25-30 times the normal level. The entire leachate must then undergo neutralization and iron precipitation. When using the hematite method for neutralization and iron precipitation, hematite formation is difficult, leading to the formation of various iron oxides, and the grade of the iron precipitation residue is less than 40%.

[0004] Patent CN202310814647.7 discloses a method for leaching and separating lead, selenium, copper, and mercury from acidic sludge in a stepwise manner. The first step involves the synergistic leaching of selenium, copper, and mercury from the acidic sludge using sulfuric acid and sodium chlorate solution. The second step involves the reduction and precipitation of selenium from the leachate using hydrochloric acid and sodium sulfite. The third step involves the precipitation of copper from the selenium-containing solution using oxalic acid, and the reduction and precipitation of mercury from the copper-containing solution using sodium hypophosphite. The leaching rates of selenium, copper, and mercury can all reach over 99%. However, the document does not address the resource utilization of the residue after the extraction of selenium, copper, and mercury.

[0005] Patent CN202211503879.2 discloses a method for efficiently separating and recovering mercury and selenium from acid sludge using microwave heating combined with alkaline oxidation. The method involves heating dry acid sludge at high power density, causing mercury and selenium to react, vaporize, and volatilize. The roasting tailings are returned to the lead treatment system. A mixture of sodium hydroxide and hydrogen peroxide absorbs the volatilized mercury and selenium gases, solidifying the mercury into dust and allowing selenium to enter the solution as sodium orthoselenate. Sulfur dioxide and nitrogen tailings are washed and purified before being used to produce acid. The selenium-mercury mixture is used to separate crude mercury, mercury soot, and sodium orthoselenate solution. Sulfuric acid is added to adjust the pH of the sodium orthoselenate solution, and sodium sulfite is added for reduction, resulting in liquid-solid separation of crude selenium and selenium-mercury waste liquid. The selenium-mercury waste liquid is returned to the washing flue gas. However, the lead slag after roasting is only returned to the lead smelting system, failing to achieve high-value utilization.

[0006] Patent CN202310187035.X discloses a method for efficiently enriching germanium using a pre-zinc removal synergistic method with germanium-containing zinc oxide flue dust neutralization. The method comprises five steps: neutral leaching, primary leaching, secondary leaching, neutralization and germanium precipitation, and post-neutralization liquid reuse. In the neutral leaching stage, a large amount of ZnO is leached from the flue dust, while the phases of Pb, Fe, Ge, As, F, and Si remain largely unchanged, achieving efficient separation of the main element Zn from impurity elements. The primary leaching stage employs an oxidative leaching process to effectively leach ZnS, breaking down the ZnS-encapsulated germanium in the flue dust and enabling the leaching of large amounts of Fe, Ge, As, F, and Si. The secondary leaching stage uses a high-acid, high-temperature leaching process to effectively leach difficult-to-treat Pb5GeO7, Zn2SiO4, and Fe2(SiO3)3, improving the leaching of Ge and Zn. However, the H2O2, MnO2, or oxygen added during the secondary leaching stage are expensive, resulting in high process costs.

[0007] Patent CN202310709463.4 discloses a method for the combined leaching of high-silicon zinc roasted ore and high-sulfur zinc oxide powder. The high-sulfur zinc oxide powder is leached in a neutral environment to obtain zinc oxide powder leaching residue and zinc powder leaching solution. The zinc powder leaching solution is mixed with high-silicon zinc roasted ore slurry for controlled silicon leaching of the high-silicon zinc roasted ore to obtain zinc ore leaching residue and zinc ore leaching solution. The zinc powder leaching residue and zinc ore leaching residue are mixed and then subjected to low-acid leaching to obtain low-leaching residue and low-leaching solution. The low-leaching residue is subjected to hot acid leaching to obtain hot-leaching residue and hot-leaching solution. The hot-acid residue is subjected to high-acid leaching to obtain lead-silver slag product and high-leaching solution. The hot-leaching solution is neutralized and reduced by high-sulfur zinc oxide powder to obtain neutralized solution and neutralized residue. The neutralized solution is subjected to mineralization and iron precipitation to obtain hematite product and iron-removed solution. It can effectively control the leaching of silicon in the high-silicon zinc roasted ore leaching process, and simultaneously achieve the oxidative leaching of sulfides in zinc oxide powder and the reductive leaching of zinc ferrite in zinc roasted ore, simplifying the leaching process of zinc roasted ore and zinc oxide powder. However, when directly using the hematite method to precipitate iron, impurities such as FeO will be generated, resulting in low iron grade. Summary of the Invention

[0008] To address the problems of low resource value of acid sludge solid waste in existing technologies, the impact of Cl in oxidized flue dust on electrodeposition, Ge dispersion in flue dust treatment, high tannic acid consumption, and difficulty in hematite precipitation, this invention proposes a method for the synergistic high-value resource utilization of acid sludge from gold smelting and zinc oxide flue dust. The method mainly includes 12 steps: alkaline washing and dechlorination, pulping, oxidative roasting, reduction ripening, chlorination roasting, neutral leaching, high-acid leaching, pre-neutralization, tannin precipitation of germanium, neutralization precipitation of iron, high-pressure ripening, and purified electrodeposition. First, alkaline washing removes chloride ions from the flue dust, reducing the burden on electrodeposition. After mixing the dechlorination solution with the acid sludge from gold smelting, low-temperature microwave roasting removes selenium, followed by high-temperature chlorination to volatilize silver. Part of the remaining iron oxides are used as an oxidant to enhance the leaching of ZnS from the neutral leaching residue of the flue dust, and another part is added as a seed crystal to the neutralization precipitation process to enhance hematite formation. The flue dust is first leached in a neutral state, followed by a high-acid oxidative leaching. Under the condition of achieving efficient germanium leaching, Ge is concentrated in the second-stage leachate, thereby reducing the consumption of tannic acid.

[0009] The acid sludge from gold smelting is produced by roasting gold and silver sulfide ores, which generates sulfur dioxide-containing flue gas. After dust collection, the sulfur dioxide flue gas and a small amount of residual dust are sent to produce acid. During the conversion, sulfuric acid is used to wash the residual dust, which is called acid sludge from gold smelting. The washing liquid is called dirty acid.

[0010] A method for the synergistic high-value resource utilization of acid sludge and zinc oxide dust from gold smelting, comprising the following specific steps:

[0011] (1) Alkali washing and dechlorination: Zinc oxide dust is washed with alkaline solution to obtain a chlorine-containing solution and dechlorinated dust;

[0012] (2) Slurrying: The acid mud from gold smelting is mixed with the chlorine-containing solution from step (1) and slurried by high-speed ball milling to obtain slurried acid mud;

[0013] (3) Oxidative roasting: Industrial oxygen is introduced into the slurry acid mud in step (2), and SeO2 flue gas and selenium-depleted products are obtained by microwave oxidative roasting;

[0014] (4) Reduction and ripening: The SeO2 flue gas in step (3) is condensed by circulating water, and then reduced and ripened by a reducing agent in sequence. Liquid-solid separation is performed to obtain selenium-extracted liquid and crude selenium.

[0015] (5) Chlorination roasting: The selenium-depleted product from step (3) is chlorinated and roasted to obtain silver-containing flue dust and silver-depleted iron slag;

[0016] (6) Neutral leaching: The dechlorinated flue dust from step (1) is neutrally leached in waste electrolyte, and the liquid and solid are separated to obtain neutral leaching residue and neutral leaching solution;

[0017] (7) High acid leaching: The neutral leaching residue from step (6) is mixed with the silver-removing iron slag from step (5) and then subjected to high acid leaching. Liquid-solid separation yields lead slag and high acid leaching solution. The lead slag is returned to the lead smelting system.

[0018] (8) Pre-neutralization: The high acid leaching solution in step (7) is pre-neutralized using zinc oxide dust, and the pre-neutralized leaching solution and pre-neutralized leaching residue are obtained by concentrated separation. The pre-neutralized leaching residue is returned to step (7) high acid leaching.

[0019] (9) Tannin precipitation of germanium: Tannin acid is added to the pre-neutralized leachate in step (8) to precipitate germanium, and liquid-solid separation is performed to obtain tannin germanium slag and germanium precipitate liquid. The tannin germanium slag is roasted to obtain germanium concentrate.

[0020] (10) Neutralizing and precipitating iron: Using the silver-removing iron slag from step (5) as hematite seed crystals, the silver-removing iron slag and alkaline reagent are added to the germanium precipitation solution to neutralize and precipitate iron to obtain a neutralized iron precipitation solution.

[0021] (11) High pressure aging: The neutralized iron-precipitated liquid in step (10) is subjected to high pressure-high temperature aging treatment, and liquid-solid separation is obtained to obtain hematite and neutralized liquid;

[0022] (12) Purification and electrowinning: The neutralized solution after step (11) and the neutral leaching solution after step (6) are mixed to obtain a mixed solution. The mixed solution is purified by zinc powder to obtain a purified solution and a purified residue. The purified residue is returned to the copper-cadmium system. The purified solution is electrowinning to obtain a zinc plate and an electrowinning solution. Different amounts of sulfuric acid are added to the electrowinning solution to adjust the acidity and then returned to the neutral leaching in step (6) and the high acid leaching in step (7) respectively.

[0023] By mass percentage, the zinc oxide flue dust in step (1) contains 40-60% Zn, 8-15% Pb, 1-2% Fe, 3-8% S, 400-3000 g / t Ge, and 50-500 g / t Cl; in the Zn phase, ZnO accounts for 82-91%, ZnS accounts for 8.8-17%, ZnFe2O4 accounts for 0.1-0.5%, and other zinc phases account for 0.1-0.5%; the alkaline solution is NaOH solution, KOH solution, or Na2CO3 solution, and the alkaline solution concentration is 0.028-0.49 g / L; the alkaline washing dechlorination temperature is 20-30℃, the alkaline washing dechlorination pH is 7.5-9, and the solid-to-chlorine ratio of the chlorine-containing solution is 2:1-3:1; the chlorine content in the chlorine-containing solution is 28-170 mg / L.

[0024] By mass percentage, the Fe content in the acid mud for gold smelting in step (2) is 58-66%, the Se content is 1-5%, and the Ag content is 300-3000 g / t; the iron phase contains 85-95% Fe2O3, 3.9-8% Fe3O4, 0.1-2% Fe2(SiO3)3, and 1-5% other iron phases; the high-speed ball milling speed is 350-390 rpm, the high-speed ball milling time is 5-8 h, and the ball milling liquid-solid ratio mL:g is 3:1-5:1;

[0025] Step (3) The microwave frequency is 918MHz or 2450MHz, and the microwave power is 70~90kWh / m 3 The oxidation roasting temperature is 500-800℃, the oxidation roasting time is 30-90min, the oxygen content in the industrial oxygen is 75-88%, and the industrial oxygen addition is 1.82-2.40L / h.

[0026] In step (4), the condensation temperature is 70–95°C, the solid-liquid ratio (mL:g) is 5:1–8:1, and the selenium content in the condensate is 88.95–142.32 g / L. The reducing agent is thiourea, hydrazine hydrate, or sodium selenite. The reduction temperature is 70–95°C, the amount of reducing agent added is 75.19–548.82 g / L, the reduction pH is 1–3, and the reduction time is 15–30 min. The aging temperature is 85–98°C and is higher than the reduction temperature. The aging time is 2–4 h, the crude selenium grade obtained after aging is 92–96%, and the residual selenium in the liquid after selenium extraction is 5.39–8.04 g / L.

[0027] In step (5), the chlorination roasting temperature is 1000–1500℃, the chlorination roasting time is 60–120 min, the mass ratio of silver-containing dust to gold smelting acid sludge is 1:1955.12–1:1232.69, the silver content in the silver-containing dust is 5.84–36.80%, the Fe content in the silver-removed iron slag is 58.44–65.87%, the mass ratio of silver-removed iron slag to gold smelting acid sludge is 0.988:1–1.002:1, and the iron phase contains 99.2–99.7% Fe2O3, 0.1–0.2% Fe3O4, 0.1–0.15% Fe2(CO3)3, and 0.1–0.5% Fe2(SiO3)3.

[0028] In step (6), the initial acidity of the neutral leaching is 101.84–128.69 g / L, the liquid-to-solid ratio (mL:g) of the waste electrolyte and germanium-containing zinc oxide dust is 4:1–8:1, the leaching temperature is 40–65℃, the leaching time is 5–30 mins, and the final pH of the neutral leaching is 4.5–5.3; the Zn content in the neutral leachate is... 2+ The content ranges from 66.95 to 80.54 g / L, Pb 2+ The content is 50-85 mg / L, Fe 2+ The content ranges from 56.23 mg / L to 0.14 g / L, Fe 3+ The content is 1.15–2.76 mg / L, Ge 4+ The content is 2-7.5 mg / L; by mass percentage, the Zn content in the neutral leaching residue is 17.99-25.50%, the Pb content is 28.80-34.62%, the Fe content is 2.30-4.79%, the S content is 12.96-16.62%, and the Ge content is 904.82-4703.7 g / t.

[0029] In step (7), the mass ratio of the silver-iron slag to the neutral leaching residue is 1:2.51 to 1:1.75, the initial acidity of the high-acid leaching is 270.67 to 327.28 g / L, the leaching temperature is 75 to 90℃, the liquid-to-solid ratio (mL:g) is 3:1 to 5:1, the leaching time is 90 to 180 mins, and the final acidity is 20 to 40 g / L. The solid-liquid ratio in the high-acid leaching process is lower than that in the neutral leaching process; the Zn in the high-acid leaching solution... 2+ The content is 21.48–26.48 g / L, Pb 2+ The content is 60-95 mg / L, Fe 2+ The content is 31.80~43.14g / L, Fe 3+ The content is 14.24–22.26 g / L, Ge 4+The content ranges from 204.83 to 1407.36 mg / L; by mass percentage, the Zn content in the lead slag is 11.35 to 15.74%, the Pb content is 50.89 to 57.31%, the Fe content is 1.47 to 2.76%, the S content is 12.60 to 19.26%, and the Ge content is 74.89 to 979.66 g / t; the Zn phases in the lead slag consist of ZnO accounting for 0.01 to 0.1%, ZnS accounting for 90.61 to 96.07%, ZnFe2O4 accounting for 1.91 to 4.68%, and other zinc phases accounting for 1.91 to 4.67%.

[0030] The endpoint pH of pre-neutralization in step (8) is 1–3, the neutralization temperature is 50–70°C, and the neutralization time is 15–45 min; the Zn in the pre-neutralized leachate 2+ The content is 40.55~49.31g / L, Pb 2+ The content is 70-105 mg / L, Fe 2+ The content is 45.35~64.31g / L, Fe 3+ The content is 0.71~1.11g / L, Ge 4+ The content ranges from 212.60 to 7794.22 mg / L; the moisture content of the pre-neutralized leaching residue is 25% to 35%, and based on the mass percentage of the pre-neutralized leaching residue, the Zn content is 10.34% to 15.43%, the Pb content is 35.32% to 41.14%, the Fe content is 2.73% to 5.87%, the S content is 9.75% to 15.36%, and the Ge content is 548.48% to 6966.64 g / t; the Zn phase in the pre-neutralized leaching residue consists of ZnO accounting for 16.39% to 32.86%, ZnS accounting for 63.56% to 73.11%, ZnFe2O4 accounting for 1.79% to 5.25%, and other zinc phases accounting for 1.79% to 6.26%.

[0031] In step (9), the amount of tannic acid added is 15 to 18 times the mass of germanium, the pH value for germanium precipitation is 1.5 to 3.5, the temperature is 55 to 65°C, and the precipitation time is 10 to 30 minutes; after germanium precipitation, the Zn content in the solution is... 2+ The content is 40.51~49.26g / L, Fe 2+ The content is 45.35~64.30g / L, Fe 3+ The content is 0.70–1.09 g / L, Ge 4+ The content ranges from 4.25 to 29.62 mg / L. By mass percentage, the Zn content in the tannin-germanium slag is 0.16 to 0.77%, the Fe content is 0.063 to 0.55%, the Ge content is 3.97 to 4.87%, and the germanium concentrate grade is 42.56 to 53.29%.

[0032] In step (10), the amount of silver-iron slag added is 10-30 g / L, the alkaline reagent is NaOH, KOH or Na2CO3, the pH of the neutralization and precipitation process is 4.5-5.5, the temperature is 55-65℃, and the time is 60-120 min.

[0033] The aging process in step (11) is carried out at a temperature of 180–220°C, an oxygen partial pressure of 0.4–0.6 MPa, and a time of 2–4 hours; the Zn content in the neutralized solution is... 2+ The content ranges from 39.70 to 48.28 g / L, Pb 2+ The content is 25-42 mg / L, Fe 2+ The content is 0.45–0.64 g / L, Fe 3+ The content ranges from 6.98 to 10.91 mg / L, Ge 4+ The content is 0.042–0.30 mg / L; by mass percentage, the Zn content in hematite is 0.67–0.90%, the Pb content is 0.037–0.057%, the Fe content is 57.56–58.78%, and the Ge content is 34.70–267.43 g / t.

[0034] In step (12), the Zn in the mixture of the neutralized solution and the neutral leachate 2+ The content ranges from 48.28 to 67.39 g / L, Pb 2+ The content is 41.95~45.44mg / L, Fe 2+ The content is 0.27–0.45 g / L, Fe 3+ The content is 4.55–6.98 mg / L, Ge 4+ The concentration was 0.30–4.69 mg / L; the purification temperature was 55–65℃, the purification time was 120–180 mins, and the pH during the purification process was 5.2–5.5; the Zn concentration in the purified solution was... 2+ The content is 60.49–67.71 g / L, Pb 2+ The content is 0.42–0.76 mg / L, Fe 2+ The content is 1.36–2.67 mg / L, Fe 3+ The content is 0.023~0.047mg / L, Ge 4+ The content is 0.68–3.02 mg / L; by mass percentage, the Zn content in the purified residue is 6.01–6.55%, the Pb content is 4.16–12.13%, the Fe content is 21.97–26.97%, and the Ge content is 685.39–4855.89 g / t; the acidity of the electrolyte after electrowinning is 100–160 g / L.

[0035] In this invention, the direct recovery rate of selenium in gold smelting acid sludge is 93.22-96.00%, the direct recovery rate of germanium in zinc oxide dust is 94.70-97.16%, and the direct recovery rate of zinc in zinc oxide dust is 93.56-97.41%.

[0036] The beneficial effects of this invention are:

[0037] (1) This invention utilizes the iron phase in the acid mud of gold smelting to enhance the leaching of zinc oxide fume and as a seed for neutralizing and precipitating iron crystals, and uses the chlorine-containing solution of zinc oxide fume to chlorinate and volatilize Ag in the acid mud, thus simultaneously realizing the high-value utilization of acid mud and zinc oxide fume in gold smelting.

[0038] (2) This invention first utilizes microwave low-temperature oxidation roasting to volatilize Se in the acid mud of gold smelting, followed by high-temperature volatilization of silver in the acid mud. The residue is mainly iron oxide, which can be directly used as seed crystals for neutralizing precipitated iron. Simultaneous stepwise roasting can realize the resource recovery of Se, Ag, and Fe, with a direct selenium recovery rate of 96.00%, a silver content of 36.80% in silver-containing flue dust, and an Fe content of 65.87% in the silver-free iron slag.

[0039] (3) In this invention, alkali washing is used to remove Cl from zinc oxide dust, preventing it from entering the zinc electrowinning system. A first-stage neutral leaching stage allows for the leaching of ZnO from the dust with minimal impurity removal, ensuring the separation of the main zinc leaching stream from other metals such as Ge. A second-stage high-acid oxidative leaching stage enables the leaching of residual zinc and a large amount of Ge, ensuring that Ge concentrates in the second-stage leaching solution while achieving efficient germanium leaching, thereby reducing tannic acid consumption. Neutralizing and precipitating germanium involves adding silver-free iron slag seed crystals to enhance the hematite precipitation process. The direct recovery rate of germanium from the dust is 97.16%, the direct recovery rate of zinc is 97.41%, the tannic acid consumption is reduced to 15 times the mass of germanium, and the iron content in the iron slag can reach 58.79%. Attached Figure Description

[0040] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0042] Example 1: The main components of the gold smelting acid mud in this example are shown in Table 1.1, and the iron phase distribution is shown in Table 1.2; the main components of zinc oxide dust are shown in Table 2.1, and the zinc phase distribution is shown in Table 2.2; the acidity of the electrolyte after electrowinning is 100 g / L;

[0043] Table 1.1 Main components of acid mud in gold smelting (wt.%)

[0044]

[0045] Table 1.2 Iron phase distribution in acid sludge from gold smelting (wt.%)

[0046]

[0047] Table 2.1 Main components of zinc oxide flue dust (wt.%)

[0048]

[0049] Table 2.2 Zinc phase distribution in zinc oxide flue dust (wt.%)

[0050]

[0051] A method for the synergistic high-value resource utilization of acid sludge and zinc oxide dust from gold smelting (see...) Figure 1 The specific steps are as follows:

[0052] (1) Alkaline washing and dechlorination: Zinc oxide dust is washed and dechlorinated by alkaline solution (NaOH solution with a concentration of 0.028 g / L) to obtain chlorine-containing solution and dechlorinated dust. The temperature of alkaline washing and dechlorination is 20℃, the pH of alkaline washing and dechlorination is 7.5, the liquid-solid ratio of alkaline washing and dechlorination is 2:1 mL:g, and the chlorine content in the chlorine-containing solution is 25 mg / L.

[0053] (2) Slurrying: The acid mud for gold smelting is mixed with the chlorine-containing solution in step (1) and slurryed by high-speed ball milling. The speed of the high-speed ball mill is 350 rpm, the high-speed ball milling time is 5 h, and the liquid-solid ratio of the ball milling is 3:1 mL:g.

[0054] (3) Oxidative roasting: Industrial oxygen is introduced into the slurry acid mud in step (2), and SeO2 flue gas and selenium-depleted products are obtained by microwave oxidative roasting; the microwave frequency is 918MHz and the microwave power is 70kWh / m 3 The oxidation roasting temperature was 500℃, the oxidation roasting time was 30min, the oxygen content in the industrial oxygen was 75%, and the industrial oxygen addition rate was 1.82L / h.

[0055] (4) Reduction and maturation: In step (3), the SeO2 flue gas is condensed by circulating water at a temperature of 70°C, with a liquid-to-solid ratio of mL:g of 5:1 and a selenium content of 142.32 g / L in the condensate. Then, it is reduced by a reducing agent, which is thiourea, at a temperature of 70°C. The amount of reducing agent added is 548.82 g / L (added in 3 portions), the reduction pH is 1, and the reduction time is 15 min. Then, it is maturated at a temperature of 85°C, which is higher than the reduction temperature, for a maturation time of 2 h. The liquid and solid are separated to obtain the selenium-extracted liquid and crude selenium. The grade of the crude selenium obtained by maturation is 92%, and the residual selenium in the selenium-extracted liquid is 5.69 g / L.

[0056] (5) Chlorination roasting: The selenium-depleted product from step (3) was subjected to chlorination roasting at a temperature of 1000℃ for 60 min to obtain silver-containing dust and silver-removed iron slag. The mass ratio of silver-containing dust to gold smelting acid sludge was 1:1955.12, and the silver content in the silver-containing dust was 5.84%. The Fe content in the silver-removed iron slag was 65.87%, and the mass ratio of silver-removed iron slag to gold smelting acid sludge was 0.997:1. In the iron phase, Fe2O3 accounted for 99.7%, Fe3O4 accounted for 0.1%, Fe2(CO3)3 accounted for 0.1%, and other iron phases accounted for 0.1%.

[0057] (6) Neutral leaching: The dechlorinated flue dust from step (1) is neutrally leached in the waste electrolyte. The initial acidity of the neutral leaching is 128.69 g / L. The liquid-to-solid ratio of the waste electrolyte to the germanium-containing zinc oxide flue dust is 4:1 mL:g. The leaching temperature is 40℃, the leaching time is 5 mins, and the final pH of the neutral leaching is 4.5. The liquid and solid are separated to obtain neutral leaching residue and neutral leaching solution. The neutral leaching solution contains Zn 2+ The content was 80.54 g / L, Pb 2+ The content is 50 mg / L, Fe 2+ The content was 89.03 mg / L, Fe 3+ The content is 1.82 mg / L, Ge 4 + The content is 2 mg / L; by mass percentage, the Zn content in the neutral leaching residue is 17.97%, Pb content is 34.62%, Fe content is 2.30%, S content is 16.62%, and Ge content is 904.82 g / t; the Zn phase in the neutral leaching residue consists of ZnO accounting for 8.31%, ZnS accounting for 86.59%, ZnFe2O4 accounting for 2.66%, and other zinc phases accounting for 2.43%.

[0058] (7) High acid leaching: The neutral leaching residue from step (6) is mixed with a small amount of the silver-removing iron residue from step (5) and then subjected to high acid leaching. The mass ratio of the silver-removing iron residue to the neutral leaching residue is 1:2.51. The initial acidity of the high acid leaching is 285.01 g / L, the leaching temperature is 75℃, the liquid-solid ratio (mL:g) is 3:1, the leaching time is 90 mins, and the final acidity is 20 g / L. The solid-liquid ratio in the high acid leaching process is lower than that in the neutral leaching process. The liquid and solid are separated to obtain lead slag and high acid leaching solution. The high acid leaching solution contains Zn 2+ The content was 26.48 g / L, Pb 2+ The content is 60 mg / L, Fe 2+ The content is 43.14 g / L, Fe 3+ The content is 22.26 g / L, Ge 4+The content was 204.83 mg / L; by mass percentage, the Zn content in the lead slag was 11.35%, the Pb content was 57.31%, the Fe content was 1.47%, the S content was 19.26%, and the Ge content was 74.89 g / t; the Zn phase in the lead slag consisted of ZnO accounting for 0.01%, ZnS accounting for 90.63%, ZnFe2O4 accounting for 4.67%, and other zinc phases accounting for 4.67%. The lead slag was returned to the lead smelting system.

[0059] (8) Pre-neutralization: The high-acid leachate from step (7) is pre-neutralized using zinc oxide dust. The final pH of the pre-neutralization is 1, the neutralization temperature is 50℃, and the neutralization time is 15min. The pre-neutralized leachate and the pre-neutralized leachate residue are obtained by concentration separation. The Zn in the pre-neutralized leachate is... 2+ The content is 40.55 g / L, Pb 2+ The content is 70 mg / L, Fe 2+ The content is 64.31 g / L, Fe 3+ The content is 1.11 g / L, Ge 4+ The content is 212.60 mg / L; the water content of the pre-neutralized leaching residue is 25%, and the Zn content is 10.34%, Pb content is 41.14%, Fe content is 2.73%, S content is 15.36%, and Ge content is 548.48 g / t based on the mass percentage of the pre-neutralized leaching residue; in the Zn phase of the pre-neutralized leaching residue, ZnO accounts for 16.39%, ZnS accounts for 73.11%, ZnFe2O4 accounts for 4.24%, and other zinc phases account for 6.26%. The pre-neutralized leaching residue is returned to step (7) high acid leaching.

[0060] (9) Tannin precipitation of germanium: Tannic acid is added to the pre-neutralized leachate from step (8) for tannin precipitation of germanium. The amount of tannic acid added is 18 times the mass of germanium. The pH value for germanium precipitation is 1.5, the temperature is 55℃, and the precipitation time is 10 min. Liquid-solid separation yields tannin-germanium residue and germanium-precipitated liquid. Zn in the germanium-precipitated liquid is... 2+ The content is 40.51 g / L, Fe 2+ The content is 64.30 g / L, Fe 3+ The content is 1.09 g / L, Ge 4+ The content is 4.25 mg / L; by mass percentage, the zinc content in the tannin germanium slag is 0.77%, the Fe content is 0.55%, and the Ge content is 3.97%; germanium concentrate can be prepared by roasting the tannin germanium slag, and the grade of the germanium concentrate obtained by roasting the tannin germanium slag is 42.56%;

[0061] (10) Neutralization and precipitation of iron: Using the silver-removed iron slag from step (5) as hematite seed crystals, the silver-removed iron slag and alkaline reagent NaOH are added to the germanium precipitation solution to neutralize and precipitate iron to obtain a neutralized iron precipitation solution; the amount of silver-removed iron slag added is 10 g / L, the pH of the neutralization and precipitation process is 4.5, the temperature is 55℃, and the time is 60 min.

[0062] (11) High-pressure aging: The neutralized iron-precipitating liquid from step (10) is subjected to high-pressure-high-temperature aging treatment, and liquid-solid separation is performed to obtain hematite and neutralized liquid; the aging treatment temperature is 180℃, oxygen partial pressure is 0.4MPa, and the time is 2h; Zn in the neutralized liquid 2+ The content was 39.70 g / L, Pb 2+ The content is 25 mg / L, Fe 2+ The content is 0.64 g / L, Fe 3+ The content was 10.91 mg / L, Ge 4+ The content is 0.042 mg / L; by mass percentage, the Zn content in hematite is 0.67%, the Pb content is 0.037%, the Fe content is 58.78%, and the Ge content is 34.70 g / t. The hematite has a high iron grade and can be directly sold for processing.

[0063] (12) Purification and electrowinning: The neutralized solution from step (11) and the neutral leachate from step (6) are mixed to obtain a mixed solution containing Zn. 2+ The content was 67.39 g / L, Pb 2+ The content was 41.95 mg / L, Fe 2+ The content is 0.27 g / L, Fe 3+ The content is 4.75 mg / L, Ge 4+ The concentration was 1.37 mg / L; the mixed solution was purified by zinc powder to obtain purified solution and purified residue. The purification temperature was 55℃, the purification time was 120 mins, and the pH during the purification process was 5.2; the Zn content in the purified solution was... 2+ The content was 67.71 g / L, Pb 2+ The content is 0.42 mg / L, Fe 2+ The content was 2.67 mg / L, Fe 3+ The content is 0.047 mg / L, Ge 4+ The content is 0.68 mg / L; by mass percentage, the Zn content in the purification residue is 6.54%, the Pb content is 4.16%, the Fe content is 26.97%, and the Ge content is 685.39 g / t; the purification residue is returned to the copper-cadmium system, and the purification liquid is electrowinning to obtain zinc plates and electrowinning liquid. The acidity of the electrowinning liquid is 100 g / L. Different amounts of sulfuric acid are added to the electrowinning liquid to adjust the acidity and then returned to step (6) neutral leaching and step (7) high acid leaching respectively.

[0064] In this embodiment, the direct recovery rate of selenium in gold smelting acid sludge is 96.00%, the direct recovery rate of germanium in zinc oxide dust is 94.70%, and the direct recovery rate of zinc in zinc oxide dust is 93.56%.

[0065] Example 2: The main components of the gold smelting acid sludge in this example are shown in Table 3.1, and the iron phase distribution is shown in Table 3.2. The main components of the zinc oxide dust are shown in Table 4.1, and the zinc phase distribution is shown in Table 4.2; the acidity of the electrolyte after electrowinning is 140 g / L.

[0066] Table 3.1 Main components of acid mud in gold smelting (wt.%)

[0067]

[0068] Table 3.2 Iron phase distribution in acid sludge from gold smelting (wt.%)

[0069]

[0070] Table 4.1 Main components of zinc oxide flue dust (wt.%)

[0071]

[0072] Table 4.2 Zinc phase distribution in zinc oxide flue dust (wt.%)

[0073]

[0074] A method for the synergistic high-value resource utilization of acid sludge and zinc oxide dust from gold smelting (see...) Figure 1 The specific steps are as follows:

[0075] (1) Alkaline washing and dechlorination: Zinc oxide dust is washed and dechlorinated by alkaline solution (KOH solution with a concentration of 0.047 g / L) to obtain chlorine-containing solution and dechlorinated dust. The alkaline washing and dechlorination temperature is 25℃, the alkaline washing and dechlorination pH is 8, the liquid-solid ratio of alkaline washing and dechlorination mL:g is 2.5:1, and the chlorine content in the chlorine-containing solution is 120 mg / L.

[0076] (2) Slurrying: The acid mud for gold smelting is mixed with the chlorine-containing solution in step (1) and slurryed by high-speed ball milling. The speed of the high-speed ball mill is 370 rpm, the high-speed ball milling time is 6 h, and the liquid-solid ratio of the ball milling is 4:1 mL:g.

[0077] (3) Oxidative roasting: Industrial oxygen is introduced into the slurry acid mud in step (2), and SeO2 flue gas and selenium-depleted products are obtained by microwave oxidative roasting; the microwave frequency is 2450MHz and the microwave power is 80kWh / m 3 The oxidation roasting temperature was 600℃, the oxidation roasting time was 60min, the oxygen content in the industrial oxygen was 85%, and the industrial oxygen addition rate was 2.40L / h.

[0078] (4) Reduction and maturation: In step (3), the SeO2 flue gas is condensed by circulating water at a temperature of 85°C, the liquid-to-solid ratio of condensate is 6:1 mL:g, and the selenium content in the condensate is 118.60 g / L. Then, it is reduced by a reducing agent, which is hydrazine hydrate. The reduction temperature is 85°C, the amount of reducing agent added is 75.19 g / L (added once), the reduction pH is 2, and the reduction time is 20 min. Then, it is maturated at a temperature of 90°C, which is higher than the reduction temperature, and the maturation time is 3 h. The liquid and solid are separated to obtain the selenium-extracted liquid and crude selenium. The grade of the crude selenium obtained by maturation is 95%, and the residual selenium in the selenium-extracted liquid is 8.04 g / L.

[0079] (5) Chlorination roasting: The selenium-depleted product from step (3) was subjected to chlorination roasting at a temperature of 1250℃ for 90 min to obtain silver-containing dust and silver-removed iron slag. The mass ratio of silver-containing dust to gold smelting acid sludge was 1:1468.03, and the silver content in the silver-containing dust was 26.29%. The Fe content in the silver-removed iron slag was 61.57%, and the mass ratio of silver-removed iron slag to gold smelting acid sludge was 1.002:1. In the iron phase, Fe2O3 accounted for 99.50%, Fe3O4 accounted for 0.2%, Fe2(CO3)3 accounted for 0.15%, and Fe2(SiO3)3 accounted for 0.15%.

[0080] (6) Neutral leaching: The dechlorinated flue dust from step (1) is neutrally leached in the waste electrolyte. The initial acidity of the neutral leaching is 105.24 g / L. The liquid-to-solid ratio of the waste electrolyte to the germanium-containing zinc oxide flue dust is 6:1 mL:g. The leaching temperature is 55℃, the leaching time is 15 mins, and the final pH of the neutral leaching is 4.8. The liquid and solid are separated to obtain neutral leaching residue and neutral leaching solution. The neutral leaching solution contains Zn 2+ The content was 67.12 g / L, Pb 2+ The content is 70 mg / L, Fe 2+ The content is 0.14 g / L, Fe 3+ The content was 2.76 mg / L, Ge 4 + The content was 6.67 mg / L; by mass percentage, the Zn content in the neutral leaching residue was 23.35%, the Pb content was 28.80%, the Fe content was 4.79%, the S content was 12.96%, and the Ge content was 4703.7 g / t; the Zn phases in the neutral leaching residue consisted of 8.43% ZnO, 86.48% ZnS, 2.54% ZnFe2O4, and 2.54% other zinc phases.

[0081] (7) High acid leaching: The neutral leaching residue from step (6) is mixed with a small amount of the silver-removing iron residue from step (5) and then subjected to high acid leaching. The mass ratio of the silver-removing iron residue to the neutral leaching residue is 1:1.89. The initial acidity of the high acid leaching is 270.67 g / L, the leaching temperature is 85℃, the liquid-solid ratio (mL:g) is 4:1, the leaching time is 150 mins, and the final acidity is 30 g / L. The solid-liquid ratio in the high acid leaching process is lower than that in the neutral leaching process. The liquid and solid are separated to obtain lead slag and high acid leaching solution. The high acid leaching solution contains Zn 2+ The content was 23.65 g / L, Pb 2+ The content is 80 mg / L, Fe 2+ The content is 40.26 g / L, Fe 3+ The content is 17.62 g / L, Ge 4+ The content is 731.91 mg / L; by mass percentage, the Zn content in the lead slag is 15.74%, the Pb content is 50.89%, the Fe content is 2.76%, the S content is 16.03%, and the Ge content is 415.58 g / t; the Zn phase in the lead slag is composed of ZnO 0.05%, ZnS 90.61%, ZnFe2O4 4.68%, and other zinc phases 4.66%, and the lead slag is returned to the lead smelting system;

[0082] (8) Pre-neutralization: The high-acid leachate from step (7) is pre-neutralized using zinc oxide dust. The final pH of the pre-neutralization is 2, the neutralization temperature is 60℃, and the neutralization time is 30 min. The pre-neutralized leachate and the pre-neutralized leach residue are obtained by concentration separation. The Zn in the pre-neutralized leachate is... 2+ The content was 45.17 g / L, Pb 2+ The content is 90 mg / L, Fe 2+ The content was 57.03 g / L, Fe 3+ The content is 0.88 g / L, Ge 4+ The content is 7794.22 mg / L; the water content of the pre-neutralized leaching residue is 30%, and the Zn content is 13.88%, Pb content is 35.32%, Fe content is 5.87%, S content is 12.36%, and Ge content is 2943.78 g / t based on the mass percentage of the pre-neutralized leaching residue; in the Zn phase of the pre-neutralized leaching residue, ZnO accounts for 17.39%, ZnS accounts for 72.11%, ZnFe2O4 accounts for 5.25%, and other zinc phases account for 5.25%. The pre-neutralized leaching residue is returned to step (7) high acid leaching.

[0083] (9) Tannin precipitation of germanium: Tannic acid was added to the pre-neutralized leachate from step (8) for tannin precipitation of germanium. The amount of tannic acid added was 17.5 times the mass of germanium. The pH value for germanium precipitation was 2.5, the temperature was 62℃, and the precipitation time was 20 min. Liquid-solid separation yielded tannin-germanium residue and the germanium-precipitated liquid. Zn was then added to the germanium-precipitated liquid. 2+The content is 45.12 g / L, Fe 2+ The content was 57.03 g / L, Fe 3+ The content is 0.86 g / L, Ge 4+ The content is 15.59 mg / L; by mass percentage, the zinc content in the tannin germanium slag is 0.25%, the Fe content is 0.13%, and the Ge content is 4.20%; germanium concentrate can be prepared by roasting the tannin germanium slag, and the grade of the germanium concentrate obtained by roasting the tannin germanium slag is 51.35%;

[0084] (10) Neutralization and precipitation of iron: Using the silver-removed iron slag from step (5) as hematite seed crystals, the silver-removed iron slag and alkaline reagent KOH are added to the germanium precipitation solution to neutralize and precipitate iron to obtain a neutralized iron precipitation solution; the amount of silver-removed iron slag added is 20g / L, the pH of the neutralization and precipitation process is 5, the temperature is 60℃, and the time is 90min.

[0085] (11) High-pressure aging: The neutralized iron-precipitating liquid from step (10) is subjected to high-pressure-high-temperature aging treatment, and liquid-solid separation is performed to obtain hematite and neutralized liquid; the aging treatment temperature is 200℃, oxygen partial pressure is 0.5MPa, and the time is 3h; Zn in the neutralized liquid 2+ The content was 44.22 g / L, Pb 2+ The content is 35 mg / L, Fe 2+ The content is 0.57 g / L, Fe 3+ The content was 8.63 mg / L, Ge 4+ The content is 0.16 mg / L; by mass percentage, the Zn content in hematite is 0.76%, the Pb content is 0.046%, the Fe content is 58.45%, and the Ge content is 129.56 g / t. The hematite has a high iron grade and can be directly sold for processing.

[0086] (12) Purification and electrowinning: The neutralized solution from step (11) and the neutral leachate from step (6) are mixed to obtain a mixed solution containing Zn. 2+ The content was 60.16 g / L, Pb 2+ The content was 45.44 mg / L, Fe 2+ The content is 0.27 g / L, Fe 3+ The content is 4.55 mg / L, Ge 4+ The concentration was 4.69 mg / L; the mixed solution was purified by zinc powder to obtain purified solution and purified residue. The purification temperature was 60℃, the purification time was 150 mins, and the pH during the purification process was 5.3; the Zn content in the purified solution was 4.69 mg / L. 2+ The content was 60.49 g / L, Pb 2+ The content is 0.45 mg / L, Fe 2+ The content was 2.67 mg / L, Fe 3+ The content is 0.045 mg / L, Ge4+ The content is 2.34 mg / L; by mass percentage, the Zn content in the purification residue is 6.55%, the Pb content is 4.46%, the Fe content is 26.70%, and the Ge content is 2324.8 g / t; the purification residue is returned to the copper-cadmium system, and the purification liquid is electrowinning to obtain zinc plates and electrowinning liquid. The acidity of the electrowinning liquid is 140 g / L. Different amounts of sulfuric acid are added to the electrowinning liquid to adjust the acidity and then returned to step (6) neutral leaching and step (7) high acid leaching respectively.

[0087] In this embodiment, the direct recovery rate of selenium in gold smelting acid sludge is 93.22%, the direct recovery rate of germanium in zinc oxide dust is 97.16%, and the direct recovery rate of zinc in zinc oxide dust is 95.36%.

[0088] Example 3: The main components of the gold smelting acid mud in this example are shown in Table 5.1, and the iron phase distribution is shown in Table 5.2; the main components of the zinc oxide dust are shown in Table 6.1, and the zinc phase distribution is shown in Table 6.2; the acidity of the electrolyte after electrowinning is 160 g / L.

[0089] Table 5.1 Main components of acid mud in gold smelting (wt.%)

[0090]

[0091] Table 5.2 Distribution of iron phases in acid sludge from gold smelting (wt.%)

[0092]

[0093] Table 6.1 Main components of zinc oxide flue dust (wt.%)

[0094]

[0095] Table 6.2 Zinc phase distribution in zinc oxide flue dust (wt.%)

[0096]

[0097] A method for the synergistic high-value resource utilization of acid sludge and zinc oxide dust from gold smelting (see...) Figure 1 The specific steps are as follows:

[0098] (1) Alkaline washing and dechlorination: Zinc oxide dust is washed and dechlorinated by alkaline solution (Na2CO3 solution with a concentration of 0.49 g / L) to obtain chlorine-containing solution and dechlorinated dust. The temperature of alkaline washing and dechlorination is 30℃, the pH of alkaline washing and dechlorination is 9, the liquid-solid ratio of alkaline washing and dechlorination is 3:1 mL:g, and the chlorine content in the chlorine-containing solution is 170 mg / L.

[0099] (2) Slurrying: The acid mud for gold smelting is mixed with the chlorine-containing solution in step (1) and slurryed by high-speed ball milling. The speed of the high-speed ball mill is 390 rpm, the high-speed ball milling time is 8 h, and the ball milling liquid-solid ratio is 5:1 mL:g.

[0100] (3) Oxidative roasting: Industrial oxygen is introduced into the slurry of step (2), and SeO2 flue gas and selenium-depleted products are obtained by microwave oxidative roasting; the microwave frequency is 2450MHz and the microwave power is 90kWh / m 3 The oxidation roasting temperature was 800℃, the oxidation roasting time was 90min, the oxygen content in the industrial oxygen was 88%, and the industrial oxygen addition rate was 2.22L / h.

[0101] (4) Reduction and maturation: In step (3), the SeO2 flue gas is condensed by circulating water at a temperature of 95°C, with a liquid-to-solid ratio of mL:g of 8:1 and a selenium content of 88.95 g / L in the condensate. Then, it is reduced by a reducing agent, which is hydrazine hydrate, at a temperature of 95°C and an amount of 283.98 g / L (added in two portions). The reduction pH is 3 and the reduction time is 30 min. Then, it is maturated at a temperature of 98°C, which is higher than the reduction temperature, for a maturation time of 4 h. The liquid and solid are separated to obtain selenium-extracted liquid and crude selenium. The grade of the crude selenium obtained by maturation is 96%, and the residual selenium in the selenium-extracted liquid is 5.39 g / L.

[0102] (5) Chlorination roasting: The selenium-depleted product from step (3) was subjected to chlorination roasting at a temperature of 1500℃ for 120 min to obtain silver-containing dust and silver-removed iron slag. The mass ratio of silver-containing dust to gold smelting acid sludge was 1:1232.69, and the silver content in the silver-containing dust was 36.80%. The Fe content in the silver-removed iron slag was 58.44%, and the mass ratio of silver-removed iron slag to gold smelting acid sludge was 0.988:1. In the iron phase, Fe2O3 accounted for 99.2%, Fe3O4 accounted for 0.2%, Fe2(CO3)3 accounted for 0.1%, and Fe2(SiO3)3 accounted for 0.5%.

[0103] (6) Neutral leaching: The dechlorinated flue dust from step (1) is neutrally leached in the waste electrolyte. The initial acidity of the neutral leaching is 101.84 g / L. The liquid-to-solid ratio of the waste electrolyte to the germanium-containing zinc oxide flue dust is 8:1 mL:g. The leaching temperature is 65℃, the leaching time is 30 mins, and the final pH of the neutral leaching is 5.3. The liquid and solid are separated to obtain neutral leaching residue and neutral leaching solution. The neutral leaching solution contains Zn 2+ The content was 66.95 g / L, Pb 2+ The content is 85 mg / L, Fe 2+ The content was 56.23 mg / L, Fe 3+ The content is 1.15 mg / L, Ge 4+The content is 7.5 mg / L; by mass percentage, the Zn content in the neutral leaching residue is 25.50%, Pb content is 31.69%, Fe content is 3.95%, S content is 10.70%, and Ge content is 1164.62 g / t; the Zn phase in the neutral leaching residue consists of ZnO accounting for 16.96%, ZnS accounting for 81.19%, ZnFe2O4 accounting for 0.92%, and other zinc phases accounting for 0.92%.

[0104] (7) High acid leaching: The neutral leaching residue from step (6) is mixed with a small amount of the silver-removing iron residue from step (5) and then subjected to high acid leaching. The mass ratio of the silver-removing iron residue to the neutral leaching residue is 1:1.75. The initial acidity of the high acid leaching is 327.28 g / L, the leaching temperature is 90℃, the liquid-solid ratio (mL:g) is 5:1, the leaching time is 180 mins, and the final acidity is 40 g / L. The solid-liquid ratio in the high acid leaching process is lower than that in the neutral leaching process. The liquid and solid are separated to obtain lead slag and high acid leaching solution. The high acid leaching solution contains Zn 2+ The content was 21.48 g / L, Pb 2+ The content is 95 mg / L, Fe 2+ The content is 31.80 g / L, Fe 3+ The content is 14.24 g / L, Ge 4+ The content is 1407.36 mg / L; by mass percentage, the Zn content in the lead slag is 14.49%, the Pb content is 53.31%, the Fe content is 1.82%, the S content is 12.60%, and the Ge content is 979.66 g / t; the Zn phase in the lead slag is composed of ZnO 0.1%, ZnS 96.07%, ZnFe2O4 1.91%, and other zinc phases 1.91%, and the lead slag is returned to the lead smelting system;

[0105] (8) Pre-neutralization: The high-acid leachate from step (7) is pre-neutralized using zinc oxide dust. The final pH of the pre-neutralization is 3, the neutralization temperature is 70℃, and the neutralization time is 45min. The pre-neutralized leachate and the pre-neutralized leach residue are obtained by concentration separation. The Zn in the pre-neutralized leachate is... 2+ The content was 49.31 g / L, Pb 2+ The content is 105 mg / L, Fe 2+ The content is 45.35 g / L, Fe 3+ The content is 0.71 g / L, Ge 4+The content is 1481.00 mg / L; the water content of the pre-neutralized leaching residue is 35%, and the Zn content is 15.43%, Pb content is 37.15%, Fe content is 4.64%, S content is 9.75%, and Ge content is 6966.64 g / t based on the mass percentage of the pre-neutralized leaching residue; in the Zn phase of the pre-neutralized leaching residue, ZnO accounts for 32.86%, ZnS accounts for 63.56%, ZnFe2O4 accounts for 1.79%, and other zinc phases account for 1.79%. The pre-neutralized leaching residue is returned to step (7) high acid leaching.

[0106] (9) Tannin precipitation of germanium: Tannic acid is added to the pre-neutralized leachate from step (8) for tannin precipitation of germanium. The amount of tannic acid added is 15 times the mass of germanium. The pH value for germanium precipitation is 3.5, the temperature is 65℃, and the precipitation time is 30 min. Liquid-solid separation yields tannin-germanium residue and germanium-precipitated liquid. Zn is then added to the germanium-precipitated liquid. 2+ The content is 49.26 g / L, Fe 2+ The content is 45.35 g / L, Fe 3+ The content is 0.70 g / L, Ge 4+ The content is 29.62 mg / L; by mass percentage, the zinc content in the tannin germanium slag is 0.16%, the Fe content is 0.063%, and the Ge content is 4.87%; germanium concentrate can be prepared by roasting the tannin germanium slag, and the grade of the germanium concentrate obtained by roasting the tannin germanium slag is 53.29%;

[0107] (10) Neutralization and precipitation of iron: Using the silver-removed iron slag from step (5) as hematite seed crystals, the silver-removed iron slag and alkaline reagent (sodium carbonate) are added to the germanium precipitation solution to neutralize and precipitate iron to obtain a neutralized iron precipitation solution; the amount of silver-removed iron slag added is 30g / L, the pH of the neutralization and precipitation process is 5.5, the temperature is 65℃, and the time is 120min.

[0108] (11) High-pressure aging: The neutralized iron-precipitating liquid from step (10) is subjected to high-pressure-high-temperature aging treatment, and liquid-solid separation is performed to obtain hematite and neutralized liquid; the aging treatment temperature is 220℃, oxygen partial pressure is 0.6MPa, and the time is 4h; Zn in the neutralized liquid 2+ The content was 48.28 g / L, Pb 2+ The content is 42 mg / L, Fe 2+ The content is 0.45 g / L, Fe 3+ The content was 6.98 mg / L, Ge 4+ The content is 0.30 mg / L; by mass percentage, the Zn content in hematite is 0.90%, the Pb content is 0.057%, the Fe content is 57.56%, and the Ge content is 267.43 g / t. The hematite has a high iron grade and can be directly sold for processing.

[0109] (12) Purification and electrowinning: The neutralized solution from step (11) and the neutral leachate from step (6) are mixed to obtain a mixed solution containing Zn. 2+ The content was 63.20 g / L, Pb 2+ The content was 76.36 mg / L, Fe 2+ The content is 0.14 g / L, Fe 3+ The content was 2.32 mg / L, Ge 4+ The concentration was 6.05 mg / L; the mixed solution was purified by zinc powder to obtain purified solution and purified residue. The purification temperature was 65℃, the purification time was 180 mins, and the pH during the purification process was 5.5; the Zn content in the purified solution was 6.05 mg / L. 2+ The content was 63.39 g / L, Pb 2+ The content is 0.76 mg / L, Fe 2+ The content was 1.36 mg / L, Fe 3+ The content is 0.023 mg / L, Ge 4+ The content is 3.02 mg / L; by mass percentage, the Zn content in the purification residue is 6.01%, the Pb content is 12.13%, the Fe content is 21.97%, and the Ge content is 4855.89 g / t; the purification residue is returned to the copper-cadmium system, and the purification liquid is electrowinning to obtain zinc plates and electrowinning liquid. The acidity of the electrowinning liquid is 160 g / L. Different amounts of sulfuric acid are added to the electrowinning liquid to adjust the acidity and then returned to step (6) neutral leaching and step (7) high acid leaching respectively.

[0110] In this embodiment, the direct recovery rate of selenium in gold smelting acid sludge is 93.94%, the direct recovery rate of germanium in zinc oxide dust is 96.01%, and the direct recovery rate of zinc in zinc oxide dust is 97.41%.

[0111] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for the synergistic high-value resource utilization of acid sludge from gold smelting and zinc oxide dust, characterized in that, The specific steps are as follows: (1) Alkali washing and dechlorination: Zinc oxide dust is washed with alkaline solution to obtain a chlorine-containing solution and dechlorinated dust; (2) Slurrying: The acid mud from gold smelting is mixed with the chlorine-containing solution from step (1) and slurried by high-speed ball milling to obtain slurried acid mud; (3) Oxidative roasting: Industrial oxygen is introduced into the slurry acid mud in step (2), and SeO2 flue gas and selenium-depleted products are obtained by microwave oxidative roasting; (4) Reduction and ripening: The SeO2 flue gas in step (3) is condensed by circulating water, and then reduced and ripened by a reducing agent in sequence. Liquid-solid separation is performed to obtain selenium-extracted liquid and crude selenium. (5) Chlorination roasting: The selenium-depleted product from step (3) is chlorinated and roasted to obtain silver-containing flue dust and silver-depleted iron slag; (6) Neutral leaching: The dechlorinated flue dust from step (1) is neutrally leached in waste electrolyte, and the liquid and solid are separated to obtain neutral leaching residue and neutral leaching solution; (7) High acid leaching: The neutral leaching residue from step (6) is mixed with the silver-removing iron slag from step (5) and then subjected to high acid leaching. Liquid-solid separation yields lead slag and high acid leaching solution. The lead slag is returned to the lead smelting system. (8) Pre-neutralization: The high acid leaching solution in step (7) is pre-neutralized using zinc oxide dust, and the pre-neutralized leaching solution and pre-neutralized leaching residue are obtained by concentrated separation. The pre-neutralized leaching residue is returned to step (7) high acid leaching. (9) Tannin precipitation of germanium: Tannin acid is added to the pre-neutralized leachate in step (8) to precipitate germanium, and liquid-solid separation is performed to obtain tannin germanium slag and germanium precipitate liquid. The tannin germanium slag is roasted to obtain germanium concentrate. (10) Neutralizing and precipitating iron: Using the silver-removing iron slag from step (5) as hematite seed crystals, the silver-removing iron slag and alkaline reagent are added to the germanium precipitation solution to neutralize and precipitate iron to obtain a neutralized iron precipitation solution. (11) High pressure aging: The neutralized iron-precipitated liquid in step (10) is subjected to high pressure-high temperature aging treatment, and liquid-solid separation is obtained to obtain hematite and neutralized liquid; (12) Purification and electrowinning: The neutralized solution after step (11) and the neutral leaching solution after step (6) are mixed to obtain a mixed solution. The mixed solution is purified by zinc powder to obtain a purified solution and a purified residue. The purified residue is returned to the copper-cadmium system. The purified solution is electrowinning to obtain a zinc plate and an electrowinning solution. Different amounts of sulfuric acid are added to the electrowinning solution to adjust the acidity and then returned to the neutral leaching in step (6) and the high acid leaching in step (7) respectively.

2. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: By mass percentage, the zinc oxide flue dust in step (1) contains 40-60% Zn, 8-15% Pb, 1-2% Fe, 3-8% S, 400-3000 g / t Ge, and 50-500 g / t Cl; in the Zn phase, ZnO accounts for 82-91%, ZnS accounts for 8.8-17%, ZnFe2O4 accounts for 0.1-0.5%, and other zinc phases account for 0.1-0.5%; the alkaline solution is NaOH solution, KOH solution, or Na2CO3 solution, and the alkaline solution concentration is 0.028-0.49 g / L; the alkaline washing dechlorination temperature is 20-30℃, the alkaline washing dechlorination pH is 7.5-9, and the solid-to-chlorine ratio of the chlorine-containing solution is 2:1-3:1; the chlorine content in the chlorine-containing solution is 28-170 mg / L.

3. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: By mass percentage, the Fe content in the acid mud for gold smelting in step (2) is 58-66%, the Se content is 1-5%, and the Ag content is 300-3000 g / t; the iron phase contains 85-95% Fe2O3, 3.9-8% Fe3O4, 0.1-2% Fe2(SiO3)3, and 1-5% other iron phases; the high-speed ball milling speed is 350-390 rpm, the high-speed ball milling time is 5-8 h, and the ball milling liquid-solid ratio mL:g is 3:1-5:1; The microwave frequency is 918MHz or 2450MHz, and the microwave power is 70-90kWh / m 3 The oxidation roasting temperature is 500-800℃, the oxidation roasting time is 30-90min, the oxygen content in the industrial oxygen is 75-88%, and the industrial oxygen addition amount is 1.82-2.40L / h.

4. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: Step (4) The condensation temperature is 70-95℃, the solid-liquid ratio (mL:g) is 5:1-8:1, the selenium content in the condensate is 88.95-142.32 g / L; the reducing agent is thiourea, hydrazine hydrate, or sodium selenite, the reduction temperature is 70-95℃, the amount of reducing agent added is 75.19-548.82 g / L, the reduction pH is 1-3, and the reduction time is 15-30 min; the aging temperature is 85-98℃ and the aging temperature is higher than the reduction temperature, the aging time is 2-4 h, the crude selenium grade obtained after aging is 92-96%, and the residual selenium in the liquid after selenium extraction is 5.39-8.04 g / L; Step (5) The chlorination roasting temperature is 1000-1500℃, the chlorination roasting time is 60-120min, the mass ratio of silver-containing dust to gold smelting acid sludge is 1:1955.12-1:1232.69, the silver content in the silver-containing dust is 5.84-36.80%; the Fe content in the silver-removed iron slag is 58.44-65.87%, the mass ratio of silver-removed iron slag to gold smelting acid sludge is 0.988:1-1.002:1, and the iron phase contains 99.2-99.7% Fe2O3, 0.1-0.2% Fe3O4, 0.1-0.15% Fe2(CO3)3, and 0.1-0.5% Fe2(SiO3)3.

5. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: Step (6) The initial acidity of neutral leaching is 101.84–128.69 g / L, the liquid-to-solid ratio (mL:g) of waste electrolyte to germanium-containing zinc oxide dust is 4:1–8:1, the leaching temperature is 40–65℃, the leaching time is 5–30 mins, and the final pH of neutral leaching is 4.5–5.3; the Zn content in the neutral leachate is... 2+ The content ranges from 66.95 to 80.54 g / L, Pb 2+ The content is 50-85 mg / L, Fe 2+ The content ranges from 56.23 mg / L to 0.14 g / L, Fe 3+ The content is 1.15–2.76 mg / L, Ge 4+ The content is 2–7.5 mg / L; by mass percentage, the Zn content in the neutral leaching residue is 17.99–25.50%, the Pb content is 28.80–34.62%, the Fe content is 2.30–4.79%, the S content is 12.96–16.62%, and the Ge content is 904.82–4703.7 g / t; in the Zn phase of the neutral leaching residue, ZnO accounts for 8.31–16.96%, ZnS accounts for 81.19–86.59%, ZnFe2O4 accounts for 0.92–2.66%, and other zinc phases account for 0.92–2.54%.

6. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: Step (7) involves mixing the silver-containing iron slag with the neutral leaching residue at a mass ratio of 1:2.51 to 1:1.

75. The initial acidity for high-acid leaching is 270.67 to 327.28 g / L, the leaching temperature is 75 to 90℃, the liquid-to-solid ratio (mL:g) is 3:1 to 5:1, the leaching time is 90 to 180 mins, and the final acidity is 20 to 40 g / L. The solid-liquid ratio in the high-acid leaching process is lower than that in the neutral leaching process. The Zn content in the high-acid leaching solution is... 2+ The content is 21.48–26.48 g / L, Pb 2+ The content is 60-95 mg / L, Fe 2+ The content is 31.80~43.14g / L, Fe 3+ The content is 14.24–22.26 g / L, Ge 4+ The content ranges from 204.83 to 1407.36 mg / L; by mass percentage, the Zn content in the lead slag is 11.35 to 15.74%, the Pb content is 50.89 to 57.31%, the Fe content is 1.47 to 2.76%, the S content is 12.60 to 19.26%, and the Ge content is 74.89 to 979.66 g / t; the Zn phases in the lead slag consist of ZnO accounting for 0.01 to 0.1%, ZnS accounting for 90.61 to 96.07%, ZnFe2O4 accounting for 1.91 to 4.68%, and other zinc phases accounting for 1.91 to 4.67%.

7. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: Step (8) The endpoint pH for pre-neutralization is 1–3, the neutralization temperature is 50–70℃, and the neutralization time is 15–45 min; the Zn in the pre-neutralized leachate 2+ The content is 40.55~49.31g / L, Pb 2+ The content is 70-105 mg / L, Fe 2+ The content is 45.35~64.31g / L, Fe 3+ The content is 0.71~1.11g / L, Ge 4+ The content ranges from 212.60 to 7794.22 mg / L; the moisture content of the pre-neutralized leaching residue is 25% to 35%, and based on the mass percentage of the pre-neutralized leaching residue, the Zn content is 10.34% to 15.43%, the Pb content is 35.32% to 41.14%, the Fe content is 2.73% to 5.87%, the S content is 9.75% to 15.36%, and the Ge content is 548.48% to 6966.64 g / t; the Zn phase in the pre-neutralized leaching residue consists of ZnO accounting for 16.39% to 32.86%, ZnS accounting for 63.56% to 73.11%, ZnFe2O4 accounting for 1.79% to 5.25%, and other zinc phases accounting for 1.79% to 6.26%. Step (9): Add tannic acid at 15–18 times the mass of germanium, precipitate germanium at a pH of 1.5–3.5, at a temperature of 55–65°C, for a precipitation time of 10–30 min; after germanium precipitation, the Zn content in the solution should be... 2+ The content is 40.51~49.26g / L, Fe 2+ The content is 45.35~64.30g / L, Fe 3+ The content is 0.70–1.09 g / L, Ge 4+ The content ranges from 4.25 to 29.62 mg / L. By mass percentage, the Zn content in the tannin-germanium slag is 0.16 to 0.77%, the Fe content is 0.063 to 0.55%, the Ge content is 3.97 to 4.87%, and the germanium concentrate grade is 42.56 to 53.29%.

8. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: In step (10), the amount of silver-removing iron slag added is 10-30 g / L, the alkaline reagent is NaOH, KOH or Na2CO3, the pH of the neutralization and precipitation process is 4.5-5.5, the temperature is 55-65℃, and the time is 60-120 min.

9. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: The aging process in step (11) is carried out at a temperature of 180–220℃, an oxygen partial pressure of 0.4–0.6 MPa, and a time of 2–4 hours; the Zn content in the neutralized solution is... 2+ The content ranges from 39.70 to 48.28 g / L, Pb 2+ The content is 25-42 mg / L, Fe 2+ The content is 0.45–0.64 g / L, Fe 3+ The content ranges from 6.98 to 10.91 mg / L, Ge 4+ The content is 0.042–0.30 mg / L; by mass percentage, the Zn content in hematite is 0.67–0.90%, the Pb content is 0.037–0.057%, the Fe content is 57.56–58.78%, and the Ge content is 34.70–267.43 g / t.

10. The method for the synergistic high-value resource utilization of gold smelting acid sludge and zinc oxide dust according to claim 1, characterized in that: In step (12), the Zn in the mixture of neutralized solution and neutral leachate 2+ The content ranges from 48.28 to 67.39 g / L, Pb 2+ The content is 41.95~45.44mg / L, Fe 2+ The content is 0.27–0.45 g / L, Fe 3+ The content is 4.55–6.98 mg / L, Ge 4+ The concentration was 0.30–4.69 mg / L; the purification temperature was 55–65℃, the purification time was 120–180 mins, and the pH during the purification process was 5.2–5.5; the Zn concentration in the purified solution was... 2+ The content is 60.49–67.71 g / L, Pb 2+ The content is 0.42–0.76 mg / L, Fe 2 + The content is 1.36–2.67 mg / L, Fe 3+ The content is 0.023~0.047mg / L, Ge 4+ The content is 0.68–3.02 mg / L; by mass percentage, the Zn content in the purified residue is 6.01–6.55%, the Pb content is 4.16–12.13%, the Fe content is 21.97–26.97%, and the Ge content is 685.39–4855.89 g / t; the acidity of the electrolyte after electrowinning is 100–160 g / L.

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