Chlorine and copper removal process for zinc hydrometallurgy

Abstract

The invention discloses a dechlorination and copper removal process for zinc hydrometallurgy in the field of metal hydrometallurgy. The dechlorination and copper removal process comprises the following steps: 1) dechlorination of a neutral leaching solution: feeding the neutral leaching solution obtained by neutral leaching and filter pressing of secondary zinc oxide mineral powder into a dechlorination tank, adding copper removal slag, replacement slag and a copper sulfate solution, adjusting the pH value of a system to 2-2.5, heating to 60-70 DEG C, and stirring for 30-50 minutes; after the content of the solution is detected to be less than 0.5 g / L, carrying out rapid filter pressing, feeding a dechlorination solution into a copper removal tank, and feeding dechlorination residues into a regeneration tank; (2) copper removal through the dechlorination liquid: zinc powder is added into the dechlorination liquid in the copper removal tank in batches, the pH value of the system is adjusted to 4-4.5, and stirring is conducted for 30-40 min; and after detecting that the content of the solution is less than 0.1 g / L, carrying out filter pressing, feeding the copper-removed solution into an iron removal station, and returning the copper-removed slag to the dechlorination tank in the step 1). The production cost is reduced through material internal circulation (copper source cyclic utilization), the impurity removal efficiency reaches the standard, no waste water is discharged, by-products are recycled, and the method is suitable for low-grade zinc raw material wet smelting.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical metal smelting, specifically a hydrometallurgical zinc smelting process for removing chlorine and copper. Background Technology

[0002] With the increasing depletion of zinc concentrate resources, low-grade ores and secondary zinc resources have gradually become the main raw materials for hydrometallurgical zinc refining. These raw materials have complex compositions, with fluctuating zinc content and high levels of chlorine and copper impurities—the chlorine content in zinc oxide dust is particularly prominent, leading to a significant increase in the concentration of impurity ions in the smelting electrolyte.

[0003] In existing processes, chloride ions severely corrode the anode plate, shortening its lifespan and increasing the lead content in the electrolyte, thus reducing the chemical purity of the deposited zinc. Furthermore, chloride ions accelerate the corrosion of stainless steel equipment, significantly increasing maintenance costs. Copper ions, on the other hand, co-deposit with zinc at the cathode during electrodeposition, affecting the chemical composition of the zinc product and, in severe cases, causing plate burnout and production interruptions.

[0004] The copper slag precipitation method commonly used in the industry for dechlorination has the problem of insufficient purification depth, making it difficult to control the chlorine content in the electrolyte within the ideal range of <0.5g / L. At the same time, most existing processes are unidirectional processes without internal material circulation design, which wastes copper resources and generates chlorine-containing wastewater, increasing environmental treatment costs.

[0005] Therefore, those skilled in the art have provided a wet zinc smelting process for removing chlorine and copper to solve the problems mentioned in the background art. Summary of the Invention

[0006] The purpose of this invention is to provide a wet zinc smelting process for removing chlorine and copper, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A wet zinc smelting process for removing chlorine and copper includes the following steps:

[0009] Step 1) Dechlorination of the intermediate leaching solution: The intermediate leaching solution obtained by neutral leaching and pressure filtration of zinc oxide ore powder is sent to a dechlorination tank. Copper removal slag, displacement slag, and copper sulfate solution are added. The pH of the system is adjusted to 2-2.5, the temperature is raised to 60-70℃, and the mixture is stirred for 30-50 minutes. The concentration of copper in the solution is then detected. After the content is <0.5g / L, it is quickly filtered by pressure. The dechlorinated liquid is sent to the copper removal tank, and the dechlorinated residue is sent to the regeneration tank.

[0010] Step 2) Copper removal with dechlorination solution: Add zinc powder in batches to the dechlorination solution in the copper removal tank, adjust the pH of the system to 4-4.5, and stir for 30-40 minutes; detect the concentration of zinc in the solution. After the content is <0.1g / L, filter press, send the copper removal liquid to the iron removal station, and return the copper removal slag to the dechlorination tank in step 1);

[0011] Step 3) Regeneration of dechlorinated sludge: Add high-chlorine water and caustic soda flakes to the dechlorinated sludge in the regeneration tank, adjust the pH of the system to 11-12, raise the temperature to 65-70℃, and stir for 3-4 hours; detect the concentration of chlorine in the solution. After the content is <0.1g / L, the solution is filtered, and the high-chlorine water is sent to a triple-effect evaporator to produce NaCl. The regenerated residue is sent to a slurry tank.

[0012] Step 4) Regenerated slag slurrying: Add waste electrolyte to the regenerated slag in the slurrying tank, stir for 30 minutes and then filter. The copper sulfate solution is returned to the dechlorination tank in Step 1), and the slurry filter residue is sent to the replacement section. In addition, copper-containing ore powder is leached with waste electrolyte, and copper-containing solution is added to the dechlorination tank in Step 1.

[0013] Step 5) Slurry Filter Residue Replacement: Add water and iron powder to the slurry filter residue in the replacement section, heat to 50-60℃, stir for 30 minutes, and then filter by pressure; the replacement residue is returned to the dechlorination tank in Step 1), and the filtrate is recycled; in the filtrate... When the content is >60g / L, it is prepared by evaporation crystallization. When the Pb content in the replacement slag is greater than 25%, the lead is recovered through open-circuit treatment.

[0014] As a further embodiment of the present invention: in step 1), the main component of the copper removal slag is elemental copper, the main components of the replacement slag are elemental copper and elemental lead, and the main component of the chlorine removal slag is cuprous chloride.

[0015] As a further aspect of the present invention: In step 1), when adding copper removal slag, replacement slag, and copper sulfate solution, the internal temperature of the system needs to be controlled. The molar ratio with elemental Cu is 1:1; the purpose of the rapid pressure filtration operation is to prevent the cuprous chloride in the dechlorination residue from redissolving and to avoid chloride ions from re-entering the dechlorination liquid.

[0016] As a further aspect of the present invention: in step 2), the amount of zinc powder added is calculated as “copper content in dechlorination liquid × 65kg”, and the zinc powder needs to be added slowly in batches at the upwind position to avoid arsine poisoning.

[0017] As a further aspect of the present invention: in step 3), when adding high-chlorine water, the liquid-solid ratio of dechlorination residue to high-chlorine water needs to be controlled at 9:1.

[0018] As a further embodiment of the present invention: in step 4), when adding waste electrolyte, the liquid-solid ratio of regenerated slag to waste electrolyte needs to be controlled to be 5-6:1; in step 5), the specific method of the open circuit treatment is: add sulfuric acid and hydrogen peroxide to the replacement slag to dissolve the elemental copper in the slag into the solution, and return the solution to the dechlorination tank in step 1), and collect and recycle the remaining lead slag separately.

[0019] As a further embodiment of the present invention: in step 3), before the high-chlorine water is sent into the triple-effect evaporator, it needs to be stored together with the waste ferrous chloride solution in step 5) in a high-chlorine water tank, and then transported to the triple-effect evaporator.

[0020] As a further aspect of the present invention: in step 5), the core reaction formula for the reaction between the iron powder and the slurry filter residue is: , .

[0021] As a further aspect of the present invention: the core reaction formula for dechlorination of the leaching solution in step 1) is: In step 2), the core reaction formula for removing copper from the dechlorination solution is: .

[0022] As a further aspect of the present invention: in step 3), the core reaction formula for the regeneration of the dechlorinated slag is as follows: In step 4), the core reaction formula for regenerated slurry production includes:

[0023] ;

[0024] ;

[0025] .

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. Internal material recycling reduces costs: Copper slag, replacement slag (elemental copper), and copper sulfate solution are all returned to the dechlorination section, realizing the internal recycling of copper resources and eliminating the need for additional external copper purchases;

[0028] 2. No wastewater discharge, environmental standards met: High-chlorine water is converted into NaCl product, and waste solutions containing ferrous chloride are converted into... The product's entire process generates no wastewater discharge, meeting environmental protection requirements.

[0029] 3. High impurity removal efficiency: After dechlorination, the solution contains... After copper removal, the solution To meet the requirements for impurity ions in the purification section of the wet zinc smelting process;

[0030] 4. Full resource recycling: by-products It can be sold as an industrial raw material, and lead slag can be recycled to recover lead, thus improving the overall economic efficiency of the process.

[0031] 5. Operational safety: The "batch addition of zinc powder at the upwind vent" operation design avoids the risk of arsine poisoning and improves production safety. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] Please see Figure 1 A wet zinc smelting process for removing chlorine and copper:

[0036] 1) Raw material parameters

[0037] Zinc oxide mineral powder (mass fraction): ;

[0038] Copper-bearing ore powder (mass fraction): Cu 8.5%, Zn 2.1%;

[0039] Waste electrolyte (mass concentration): ;

[0040] Zinc powder (purity): 98%;

[0041] Caustic soda flakes (purity): 99%;

[0042] Iron powder (purity): 95%.

[0043] 2. Preparation process:

[0044] Step 1) Dechlorination of the immersion solution

[0045] Neutral leaching: Take 10 tons of zinc oxide ore powder, add sulfuric acid solution for neutral leaching, and filter after leaching to obtain... Intermediate extract (detection indicators: );

[0046] Dechlorination reaction: Add copper removal slag (containing 90% Cu, 0.3t), replacement slag (containing 60% Cu, 20% Pb, 0.2t), and copper sulfate solution to a 10m³ leaching solution. ),control Molar ratio 1:1; adjust pH to 2.2, heat to 65℃, and stir for 40 min;

[0047] Filtration results: Detection indicators for dechlorinated liquid (10.2 m³): (Transported to copper removal tank); Dechlorination slag (wet weight 1.2t) testing indicators: containing (Transported to the regeneration tank).

[0048] Step 2) Dechlorination solution for copper removal

[0049] Zinc powder addition: Follow the instructions in the dechlorination solution. "Calculate and add 0.55t of 98% zinc powder in batches (operation at the upwind vent);"

[0050] Copper removal reaction: Adjust pH to 4.2, heat to room temperature, and stir for 35 minutes;

[0051] Filtration results: Copper removal solution ( ) Detection indicators: (Transported to the iron removal station); Copper removal slag (wet weight 0.32t) test index: Cu content 92% (return to step 1 dechlorination tank).

[0052] Step 3) Regeneration of dechlorination slag

[0053] Regeneration reaction: Add 1.2t of dechlorinated residue to the regeneration tank, and add high-chlorine water ( Add 0.45t of 99% caustic soda flakes (liquid-to-solid ratio 9:1), adjust pH to 11.5, heat to 68℃, and stir for 3.5h;

[0054] Filtration results: High-chlorine water (10.6 m³) test indicators: (Transported to a triple-effect evaporator); Regenerated residue (wet weight 0.8t) testing indicators: including... (Transported to the pulping tank);

[0055] Triple-effect evaporation results: After evaporation, concentration, cooling and crystallization, 0.72t of NaCl powder (purity 98.5%) was obtained from the high-chlorine water.

[0056] Step 4): Regenerated slurry

[0057] Pulping reaction: Add 0.8t of recycled slag and waste electrolyte to the pulping tank. (Liquid-to-solid ratio 5.6:1), stir for 30 minutes;

[0058] Pressure filtration results: Copper sulfate solution ( ) Detection indicators: (Return to step 1, dechlorination tank); Slurry filter residue (wet weight 0.5t) test indicators: content (Transported to the replacement tank);

[0059] Copper regeneration supplementation: Take 0.5t of copper-containing ore powder, add 1.2m³ of waste electrolyte for leaching, and obtain a copper-containing solution ( , ), and replenish to the dechlorination tank in step 1.

[0060] Step 5) Slurry filter residue replacement and wastewater treatment

[0061] Displacement reaction: Add 0.5t of slurry filter residue to the displacement tank, and add water. Add 0.12t of 95% iron powder, heat to 55℃, and stir for 30 minutes;

[0062] Filtration results: Replacement residue (wet weight 0.45t) test indicators: Cu 62%, Pb 22% (return to step 1 dechlorination tank); filtrate ( ) Detection indicators: (Entering the replacement system loop);

[0063] Filtrate circulation and wastewater treatment: After the filtrate is recycled 3 times, it is tested. When the concentration rises to 62 g / L, replace with fresh water; discard the filtrate ( The mixture is fed into an evaporator crystallizer to obtain... (Purity 97.8%)

[0064] Open circuit treatment verification: Take 0.2t of displacement slag with a lead content of 26%, and add 0.5t of sulfuric acid (10% concentration). 0.05t of hydrogen peroxide (30% concentration) was dissolved to obtain a copper-containing solution. Return to step 1, dechlorination tank; the remaining lead slag (wet weight 0.08t) contains 85% Pb and is collected and recycled.

[0065] Example 2

[0066] Some process parameters were adjusted, while the remaining conditions were the same as in Example 1. The specific parameters and results are as follows:

[0067] Step 1) Dechlorination of the intermediate leaching solution: pH=2.0, temperature 60℃, stirring time 50min, dechlorination solution ;

[0068] Step 2) Copper removal with dechlorination solution: pH=4.0, stirring time 40min, copper removal solution ;

[0069] Step 3) Regeneration of dechlorinated sludge: pH=11.0, temperature 65℃, stirring time 4h, high chlorine water 0.70t of NaCl product (purity 98.2%)

[0070] Step 4) Regenerated slurry: liquid-to-solid ratio 5:1, stirring time 30 min, copper sulfate solution. 43g / L;

[0071] Step 5) Slurry filter residue replacement and wastewater treatment: temperature 50℃, stirring time 30min. 0.33t of product (97.5% purity);

[0072] After adjusting the process parameters, the final indicators for chlorine and copper removal still meet the requirements. "Requirements, by-products" The yield and purity of the product deviated from those of Example 1 by less than 5%, which proves that the process of the present invention has good parameter adaptability and stability, and can achieve efficient impurity removal and resource recovery without strict control of a single parameter.

[0073] This invention reduces production costs through internal material circulation (copper source recycling), achieves satisfactory impurity removal efficiency, produces no wastewater, and minimizes byproducts. It enables resource utilization and is suitable for hydrometallurgical processing of low-grade zinc raw materials.

[0074] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A process for the removal of chlorine and copper from zinc hydrometallurgy, characterized by: It comprises the following steps: Step 1), removing chlorine from the intermediate leaching solution: the intermediate leaching solution obtained by neutral leaching and filter pressing of the secondary zinc oxide ore powder is sent into a chlorine removal tank, copper removal residue, displacement residue and copper sulfate solution are added, the pH of the system is adjusted to 2-2.5, the temperature is raised to 60-70℃, and stirring is carried out for 30-50 min; after detecting that the content of copper in the solution is <0.5 g / L, the solution is quickly filter pressed, the chlorine removal solution is sent into a copper removal tank, and the chlorine removal residue is sent into a regeneration tank. after detecting that the content of copper in the solution is <0.5 g / L, the solution is quickly filter pressed, the chlorine removal solution is sent into a copper removal tank, and the chlorine removal residue is sent into a regeneration tank. Step 2), copper removal from the dechlorination solution: zinc powder is added to the dechlorination solution in the copper removal tank in batches, the pH of the system is adjusted to 4-4.5, and stirring is performed for 30-40 min; after the content of the solution is detected to be <0.1 g / L, pressure filtration is performed, the copper removal solution is sent to the iron removal post, and the copper removal residue is returned to the dechlorination tank in step 1). Step 2), copper removal from the dechlorination solution: zinc powder is added to the dechlorination solution in the copper removal tank in batches, the pH of the system is adjusted to 4-4.5, and stirring is performed for 30-40 min; after the content of the solution is detected to be <0.1 g / L, pressure filtration is performed, the copper removal solution is sent to the iron removal post, and the copper removal residue Step 3), regeneration of the chlorine-removing residue: high-chlorine water and caustic soda are added to the chlorine-removing residue in the regeneration tank, the pH of the system is adjusted to 11-12, the temperature is raised to 65-70°C, and stirring is carried out for 3-4 h; after detecting the content of the solution to be <0.1 g / L, pressure filtration is carried out, the high-chlorine water is fed into a three-effect evaporator to prepare NaCl, and the regenerated residue is fed into a slurry tank. Step 3), regeneration of the chlorine-removing residue: high-chlorine water and caustic soda are added to the chlorine-removing residue in the regeneration tank, the pH of the system is adjusted to 11-12, the temperature is raised to 65-70°C, and stirring is carried out for 3-4 h; after detecting the content of the solution to be <0.1 g / L, pressure filtration is carried out, Step 4), regeneration slag slurry: add waste electrolyte into the slurry tank of the regeneration slag, stir for 30 min, then filter press, the copper sulfate solution returns to the chlorine removal tank of step 1), and the slurry filter residue is sent to the displacement section; another waste electrolyte is used to leach copper-containing ore powder, and the copper-containing solution is supplemented to the chlorine removal tank of step 1); Step 5) Slurry Filter Residue Replacement: Add water and iron powder to the slurry filter residue in the replacement section, heat to 50-60℃, stir for 30 minutes, and then filter by pressure; the replacement residue is returned to the dechlorination tank in Step 1), and the filtrate is recycled; in the filtrate... When the content is >60g / L, it is prepared by evaporation crystallization. When the Pb content in the replacement slag is greater than 25%, the lead is recovered through open-circuit treatment.

2. A process for the removal of chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 1), the main component of the copper removal slag is elemental copper, the main component of the displacement slag is elemental copper and elemental lead, and the main component of the chlorine removal slag is cuprous chloride.

3. A process for the removal of chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 1), when the copper removal residue, the displacement residue and the copper sulfate solution are added, the molar ratio of the copper removal residue to the copper sulfate solution is controlled to be 1:1 The molar ratio of the copper removal residue to the copper sulfate solution is 1:1; the operation purpose of the rapid pressure filtration is to prevent the redissolution of cuprous chloride in the copper removal residue and to avoid the reentry of chloride ions into the copper removal solution.

4. The process for removing chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 2), the amount of zinc powder added is calculated according to "copper content in chlorine removal solution x 65 kg", and the zinc powder needs to be added slowly in batches at the upwind position to avoid arsenic poisoning.

5. The process for removing chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 3), when adding high-chlorine water, the liquid-solid ratio of chlorine removal slag and high-chlorine water needs to be controlled at 9:

1.

6. A process for the removal of chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 4), when adding waste electrolyte, the liquid-solid ratio of regeneration slag and waste electrolyte needs to be controlled at 5-6:1; in step 5), the specific way of open circuit treatment is: adding sulfuric acid and hydrogen peroxide to the displacement slag to dissolve the elemental copper in the slag into the solution, the solution returns to the chlorine removal tank of step 1), and the remaining lead slag is collected and recycled separately.

7. A process for the removal of chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 3), the high-chlorine water needs to be stored in the high-chlorine water tank together with the abandoned ferrous chloride-containing solution in step 5) before being sent to the three-effect evaporator, and then uniformly transported to the three-effect evaporator.

8. The process for removing chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 5), the core reaction of the reaction of the iron powder with the slurried filter residue is: , .

9. The process for removing chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, The core reaction formula of the chlorine removal in the immersion solution in step 1) is The core reaction formula of the copper removal in the chlorine removal solution in step 2) is .

10. The process for removing chlorine and copper from zinc hydrometallurgy according to claim 1, characterized in that, In step 3), the core reaction formula for the regeneration of the chlorination residue is In step 4), the core reaction formula for the slurry of the regenerated residue includes: ； ； 。

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