Treatment system for continuous and efficient defluorination in zinc sulfate solution

Abstract

The utility model discloses a treatment system for continuous and efficient defluorination in a zinc sulfate solution, and belongs to the technical field of nonferrous metallurgy-waste material recycling. Comprising a material preparation unit, an acid dissolution-defluorination unit and a discharging unit, the acid dissolution-defluorination unit comprises a high-fluorine waste electrolyte tank and a plurality of defluorination tanks; wherein the discharge port of the high-fluorine waste electrolyte tank is connected with the feed ports of the plurality of defluorination tanks respectively. According to the utility model, fluorine ions in the self-produced waste liquid of the zinc electrodeposition system are directly removed through aluminum scraps produced by cutting and processing waste cathode aluminum plates of the zinc electrodeposition system in the zinc hydrometallurgy, so that the defluorination of the zinc hydrometallurgy system can be realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of nonferrous smelting and waste material recycling and reuse, and more specifically relates to a low-cost processing system for continuous and efficient defluorination in a zinc sulfate solution. Background Art

[0002] At present, the hydrometallurgical zinc smelting process is dominant in zinc smelting production. Its basic process is: various zinc smelting raw materials, such as zinc sulfide concentrate, roasted products of zinc sulfide concentrate, zinc oxide ore / zinc oxide smoke, etc. are leached with sulfuric acid, and the zinc in the raw materials becomes zinc sulfate and enters the solution. The reaction is:

[0003] ZnO+H2SO4=ZnSO4+H2O

[0004] ZnS+H2SO4+0.5O2=ZnSO4+S+H2O

[0005] During leaching, some other components in the raw materials are insoluble, while others are fully or partially dissolved into the solution along with zinc. After the leached slurry is subjected to liquid-solid separation to remove the insoluble residue, the zinc sulfate solution containing various impurities is purified and electrolytically deposited to deposit zinc from the solution. Finally, the zinc is stripped from the cathode and melted into ingots. With the continuous mining of mineral resources in recent years, zinc ore tends to be poor, fine and impure, resulting in low grade and high impurity content of zinc concentrate produced by flotation. At the same time, hydrometallurgical zinc smelting enterprises gradually increase the processing capacity of secondary zinc-containing materials, such as zinc oxide dust / rotary kiln zinc oxide, etc. The recovery of valuable elements such as zinc, indium, and lead is of great significance to zinc smelting enterprises.

[0006] In the hydrometallurgical zinc smelting system, fluoride and chloride ions mainly come from zinc concentrate, zinc oxide smoke from the lead system, zinc oxide from rotary kilns, and externally processed zinc roasted sand. - ]≤80mg / L, [Cl -]≤400mg / L or so. High fluoride and chloride ions will corrode equipment and deteriorate the working environment. In addition, fluoride and chloride ions can corrode the aluminum oxide film on the surface of the cathode aluminum plate in zinc electrowinning, exposing more aluminum matrix as zinc nucleation points, making it difficult to peel off the electro-zinc sticking plate. When the fluoride ion in the electrolyte is too high, it will change the morphology of zinc, making it nodular and causing the plate surface to be rough. At the same time, the acid mist volatilized from the surface of the zinc electrowinning tank will also corrode the cathode plate and equipment. By using inhibitors (foaming agents) to control the acid mist, certain results can be achieved, but it will cause a decrease in current efficiency and an increase in energy consumption. With the promotion of automated mechanical zinc stripping, the concentration of fluoride and chloride ions is bound to be required to be further reduced. However, as high-quality low-fluoride zinc raw materials are becoming less and less, the cost of low-fluoride raw materials is gradually rising, and the use of relatively cheap high-fluoride ore has become a trend. Although adsorption, zinc sulfate crystal precipitation, ion exchange, goethite method, etc. can be used to reduce the fluoride ion concentration in zinc sulfate solution, due to the large volume and complex composition of the solution in the wet zinc smelting system, the current methods for removing fluoride from zinc sulfate solution have certain disadvantages in terms of reagent selection, energy consumption, reaction time, equipment investment, and fluoride removal cost.

[0007] Therefore, developing a low-cost treatment system for continuous, efficient and defluorination in zinc sulfate solution is an urgent problem to be solved by those skilled in the art. Utility Model Content

[0008] In view of this, the utility model provides a low-cost treatment system for continuous and efficient defluorination in zinc sulfate solution. The defluorination of the hydrometallurgical zinc smelting system can be achieved by directly removing the fluoride ions in the self-produced waste liquid of the zinc electrowinning system through the aluminum chips produced by cutting and processing the discarded cathode aluminum plates of the hydrometallurgical zinc electrowinning system.

[0009] In order to achieve the above purpose, the technical concept of the utility model is: by using the waste cathode aluminum plates of the hydrozinc electrowinning system to cut and process them into aluminum chips, the fresh metal surface of the aluminum chips produced is uneven and the specific surface area is significantly increased, and this is used as a defluorination medium, and by flowing into the zinc electrowinning waste electrolyte, the fresh metal surface of the aluminum chips reacts with the hydrogen ions in the solution to generate trivalent aluminum ions, which are then combined with the fluoride ions in the solution to generate aluminum fluoride. Under acidic conditions, the solubility of aluminum fluoride is low and it is removed in the form of precipitation. This method not only realizes a large-scale defluorination of the hydrozinc smelting system, but also realizes the secondary comprehensive utilization of the waste cathode aluminum plates. The residual defluorinated aluminum chips and the waste cathode aluminum plates can be sold simultaneously.

[0010] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0011] A treatment system for continuous and efficient defluorination in a zinc sulfate solution comprises an acid dissolution-defluorination unit and a discharge unit; the acid dissolution-defluorination unit comprises a high-fluorine waste electrolyte tank and a plurality of defluorination tanks; wherein the discharge port of the high-fluorine waste electrolyte tank is respectively connected to the feed ports of the plurality of defluorination tanks; and the discharge ports of the plurality of defluorination tanks are respectively connected to the discharge unit.

[0012] The technical concept of adopting the above technical scheme is: if only one defluorination tank is selected for defluorination, it is necessary to stop the machine regularly to replace the aluminum chips, and continuous defluorination cannot be achieved; the utility model adopts multiple defluorination tanks to participate in the operation in turn. Although it is still necessary to stop the machine regularly to replace the aluminum chips, continuous defluorination can be achieved, that is, during the shutdown of defluorination tank one, defluorination tank two is put into use.

[0013] Preferably, the discharge unit comprises a precipitation collection module and a solution collection module.

[0014] Preferably, the precipitation collection modules are respectively connected to the precipitation discharge ports of the several defluorination tanks; the solution collection modules are respectively connected to the solution discharge ports of the several defluorination tanks; and the several defluorination tanks are arranged in parallel.

[0015] Preferably, the solution collection module comprises a low-fluorine spent electrolyte tank.

[0016] Preferably, overflow pipes are respectively arranged on the tops of the solution discharge ports of the plurality of defluorination tanks; and the overflow pipes are respectively connected to the feed ports of the low-fluorine waste electrolyte tanks.

[0017] Preferably, the treatment system further comprises a hydrometallurgical zinc smelting unit; the discharge port of the low-fluorine spent electrolyte tank is connected to the solution feed port of the hydrometallurgical zinc smelting acid leaching unit.

[0018] The beneficial effect of adopting the above technical solution is that the low-fluorine waste electrolyte is returned to the hydrometallurgical zinc leaching process for secondary utilization.

[0019] Furthermore, the processing system also includes a material preparation unit to provide materials for the defluorination tank.

[0020] Preferably, the material preparation unit is a high-speed metal chip cutting machine.

[0021] The technical concept of adopting the above technical solution is: At present, various wet zinc smelting enterprises often set up a cathode aluminum plate repair process in order to reduce the procurement cost of cathode aluminum plates. This process includes the use of chip cutters and other equipment. Therefore, processing some discarded cathode aluminum plates into aluminum chips does not require additional related investment, but only requires increasing the number of related operators or working hours.

[0022] Preferably, the discharge port of the high-fluorine spent electrolyte tank and the feed ports of the plurality of defluorination tanks are both located at the bottom of the tank.

[0023] Preferably, the treatment system further comprises: a liquid delivery pump for delivering high-fluorine / low-fluorine waste electrolyte.

[0024] It can be seen from the above technical solutions that, compared with the prior art, the beneficial effects achieved by the utility model are:

[0025] 1. The materials involved in the utility model are simple, namely, the waste electrolyte produced by the zinc electrowinning system and the discarded cathode aluminum plate, which can be supplied inside the zinc electrowinning system without external procurement.

[0026] 2. The process is simple and no new harmful impurity elements are introduced, which is system-friendly.

[0027] 3. The defluorination efficiency is high and can reach more than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 This is the process flow chart of the current hydrometallurgical zinc smelting principle.

[0030] Figure 2 This is the equipment connection diagram for this low-cost processing system.

[0031] Figure 3 An annotated diagram of the equipment for this low-cost treatment system.

[0032] Among them, 1 is a high-speed metal chip cutting machine, 2 is a high-fluorine waste electrolyte tank, 3 is a defluorination tank one, 4 is a defluorination tank two, 5 is an overflow pipe, 6 is an overflow pipe, 7 is a low-fluorine waste electrolyte tank, 8 is a sedimentation discharge port, 9 is a sedimentation discharge port, and 10 is a wet zinc smelting acid leaching unit. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] Industrial hydrometallurgy of zinc uses the following smelting processes according to different raw materials:

[0035] (1) Zinc sulfide concentrate-roasting-leaching-purification-electrodeposition process;

[0036] (2) Zinc sulfide concentrate - oxygen-enriched direct acid leaching (normal pressure or pressurized) - purification - electrowinning process;

[0037] (3) Zinc oxide ore / zinc oxide dust-direct acid leaching-purification-electrodeposition process.

[0038] The principle process flow of hydrometallurgical zinc smelting with various raw materials is shown in Figure 1 shown.

[0039] The current fluorine removal methods in the industry can generally be divided into two categories:

[0040] 1. Removal before leaching: For zinc oxide: there are two methods: pyrolysis (multi-chamber furnace or rotary kiln roasting) and wet alkaline washing;

[0041] 2. Removal after leaching: For the wet zinc smelting solution system, the wet defluorination method from the solution involves fluorine removal. See Table 1:

[0042] Table 1 List of wet defluorination

[0043]

[0044] In view of the above-mentioned current situation of defluorination in the wet zinc smelting solution system, the utility model seeks a low-cost, simple process flow wet defluorination process which is bound to become the goal pursued by wet zinc smelting enterprises.

[0045] Example 1

[0046] A continuous and efficient defluorination treatment system in a zinc sulfate solution, comprising an acid dissolution-defluorination unit and a discharge unit;

[0047] The acid dissolution-defluorination unit includes a high-fluorine waste electrolyte tank 2, a defluorination tank 1 3 and a defluorination tank 2 4; wherein the discharge port of the high-fluorine waste electrolyte tank 2 is connected to the feed port of the defluorination tank 1 3 and the feed port of the defluorination tank 2 4 respectively.

[0048] Furthermore, the high-fluorine waste electrolyte tank 2, the defluorination tank 1 3 and the defluorination tank 2 4 are connected by pipelines; the solution outlets of the pipelines are at the bottom of the defluorination tank 1 3 and the defluorination tank 2 4.

[0049] Furthermore, the discharge ports of the defluorination tank 1 3 and the defluorination tank 2 4 are respectively connected to the discharge units.

[0050] Furthermore, the discharge unit includes a precipitation collection module and a solution collection module. The precipitation collection module is respectively connected to the precipitation discharge ports of the defluorination tank 1 3 and the defluorination tank 2 4; the solution collection module is respectively connected to the solution discharge ports of the defluorination tank 1 3 and the defluorination tank 2 4; the defluorination tank 1 3 and the defluorination tank 2 4 are arranged in parallel.

[0051] Furthermore, the solution collection module is a low-fluorine spent electrolyte tank 7 .

[0052] Furthermore, overflow pipes 5 and 6 are respectively arranged at the top of the solution discharge port of the defluorination tank 1 3 and the solution discharge port of the defluorination tank 2 4; the overflow pipe 5 and the overflow pipe 6 are respectively connected to the feed port of the low-fluorine waste electrolyte tank 7.

[0053] Furthermore, it also includes: a wet zinc smelting acid leaching unit 10, and the discharge port of the low-fluorine waste electrolyte tank 7 is connected to the solution feed port of the wet zinc smelting acid leaching unit 10.

[0054] Furthermore, it also includes a material preparation unit high-speed metal chip cutting machine 1.

[0055] Example 2

[0056] Application of a continuous and efficient defluorination treatment system in a zinc sulfate solution.

[0057] 1. Aluminum chips preparation

[0058] The waste cathode aluminum plates from the hydrometallurgical zinc electrowinning system are cut by a high-speed metal chip cutter 1 to become aluminum chips (thickness < 1.0 mm), and the fresh aluminum chips are used as defluorination materials for waste electrolyte of the hydrometallurgical zinc smelting system.

[0059] 2. Continuous defluorination treatment

[0060] 1) Feed

[0061] A. Aluminum chips: When the tank is empty, add fresh aluminum chips into the defluorination tank manually;

[0062] B. High-fluorine waste electrolyte: The high-fluorine waste electrolyte (sulfuric acid concentration is generally 140-180 g / L) stored in the high-fluorine waste electrolyte tank 2 is continuously pumped to the defluorination tank 1 3 (or the defluorination tank 2 4).

[0063] Among them, defluorination tank 1 3 and defluorination tank 2 4 take turns to participate in the operation, that is, when defluorination tank 1 3 is stopped, defluorination tank 2 4 is put into use to achieve continuous defluorination. The process control conditions of the defluorination tank are liquid-solid ratio of 2 to 4:1, temperature of 35 to 40°C (i.e. waste electrolyte solution temperature), and reaction time of 1 to 4 hours.

[0064] 2) Acid dissolution-defluorination

[0065] As the high-fluorine waste electrolyte continuously injected into the defluorination tank 1 3 (or the defluorination tank 2 4) continues over time, the solution gradually fades from pink (even grayish white in some areas) and entrains bubbles, ultimately achieving continuous defluorination.

[0066] 3) Discharging

[0067] A. Low-fluorine waste electrolyte: With the continuous injection of high-fluorine waste electrolyte, the solution in the defluorination tank 3 (or defluorination tank 4) overflows to the low-fluorine waste electrolyte tank 7 through the overflow pipe 5 (or 6) of the defluorination tank 3 (or defluorination tank 4). According to production needs, the low-fluorine waste electrolyte stored in the low-fluorine waste electrolyte tank can be pumped back to the main acid leaching process of the wet zinc smelting acid leaching unit 10 at any time for use.

[0068] B. Defluorination aluminum chips: as the defluorination efficiency decreases over time, the defluorination tank 3 (or the defluorination tank 2 4) is stopped and the defluorination tank 3 (or the defluorination tank 2 4) is emptied, and the defluorination aluminum chips are emptied from the sedimentation discharge port 8 (or 9) at the bottom of the defluorination tank 3 (or the defluorination tank 2 4).

[0069] Defluorinated aluminum chips and discarded cathode aluminum plates from the hydrometallurgical zinc electrowinning system can be sold simultaneously.

[0070] The chemical reaction that occurs during continuous defluorination treatment is:

[0071] 1) Active aluminum acid solution

[0072] The waste cathode aluminum plate (the surface of the metal aluminum is covered with a very dense aluminum oxide protective film and is not corroded by acid) is chipped into aluminum chips, and the exposed fresh aluminum metal surface is in contact with the H in the waste electrolyte (sulfuric acid system) solution. + The ions react to release Al 3+ ion:

[0073] Al+3H + =Al 3+ +3H2↑………………………………………………(1)

[0074] The utility model is based on the fact that the waste electrolyte is easy to react with the metal surface of fresh aluminum scraps in a high acid environment, that is, part of the active aluminum on the metal surface of the aluminum scraps is dissolved by the high acid to become trivalent aluminum ions.

[0075] 2) Defluorination by precipitation of aluminum fluoride

[0076] Al in the waste electrolyte 3+ ions, will react with the F - Combined to form AlF3, AlF3 has low solubility in acid solution and is removed in the form of precipitation. Chemical reactions involved:

[0077] Al 3+ +3F - =AlF3↓…………………………………………………………(2)

[0078] The utility model uses Al 3+ Ions act as defluorination media and react with F in the waste electrolyte. -Combined to form aluminum fluoride, aluminum fluoride precipitates as an insoluble substance in the acidic environment of the waste electrolyte.

[0079] The above process will leave some unreacted aluminum chips, which can eventually be sold together with the waste cathode aluminum plates.

[0080] Example 3

[0081] Application of a continuous and efficient defluorination treatment system in a zinc sulfate solution.

[0082] The difference from Example 2 is that the F content of the high-fluorine waste electrolyte is 274.65 mg / L, the waste liquid contains 153.06 g / L of acid, the defluorination tank process control conditions are a liquid-to-solid ratio of 4:1, a temperature of 36°C (i.e., the waste electrolyte solution temperature), and a reaction time of 3h.

[0083] After acid dissolution-defluorination treatment, a low-fluorine waste electrolyte of 9.20 mg / L (defluorination rate 96.65%) was obtained.

[0084] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

Claims

1. A continuous and efficient defluorination treatment system in a zinc sulfate solution, characterized in that: It includes an acid dissolution-defluorination unit and a discharge unit; The acid dissolution-defluorination unit comprises a high-fluorine waste electrolyte tank and a plurality of defluorination tanks; Among them, the discharge port of the high-fluorine waste electrolyte tank is respectively connected to the feed ports of the several defluorination tanks; and the discharge ports of the several defluorination tanks are respectively connected to the discharge units.

2. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 1, characterized in that: The discharge unit includes a precipitation collection module and a solution collection module.

3. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 2, characterized in that: The precipitation collection modules are respectively connected to the precipitation discharge ports of the plurality of defluorination tanks; the solution collection modules are respectively connected to the solution discharge ports of the plurality of defluorination tanks; The plurality of defluorination tanks are arranged in parallel.

4. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 3, characterized in that: The solution collection module includes a low-fluorine spent electrolyte tank.

5. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 4, characterized in that: Overflow pipes are respectively arranged on the tops of the solution discharge ports of the plurality of defluorination tanks; The overflow pipes are respectively connected to the feed ports of the low-fluorine spent electrolyte tanks.

6. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 5, characterized in that: Also includes: The wet zinc smelting acid leaching unit, the discharge port of the low-fluorine waste electrolyte tank is connected to the solution feed port of the wet zinc smelting acid leaching unit.

7. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 1, characterized in that: It also includes a material preparation unit, which provides materials for the defluorination tank.

8. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 7, characterized in that: The material preparation unit includes a high-speed metal chip cutter.

9. A continuous and efficient defluorination treatment system in a zinc sulfate solution according to claim 1, characterized in that: The discharge port of the high-fluorine waste electrolyte tank and the feed ports of the plurality of defluorination tanks are both located at the bottom of the tank.

10. The system for continuous and efficient defluorination in zinc sulfate solution according to claim 1, characterized in that: Also includes: A liquid delivery pump, wherein the liquid delivery pump is used to deliver high-fluorine / low-fluorine waste electrolyte.

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