Proton exchange membrane, preparation method, and device and method for extracting sulfuric acid from ore leachate and removing thallium / arsenic

Abstract

The invention provides a proton exchange membrane, a preparation method, a device and a method for extracting sulfuric acid from ore leachate to remove thallium / arsenic, and the proton exchange membrane is prepared by the following steps: taking crosslinked polyphenylene sulfide particles with hydrophilic functional groups on the surfaces, BaSO4 powder and a high-molecular polymer as raw materials, performing mixing and fibration treatment, pressing into a membrane material, soaking the membrane material in sulfuric acid, and drying to obtain the thallium / arsenic removal membrane. Taking out and drying to obtain the proton exchange membrane. The polyphenylene sulfide particles of the diaphragm are flat in the membrane, sulfur sites of the polyphenylene sulfide particles are combined with protons through dipole adsorption and reach a saturated state, and a nanoscale efficient proton transmission channel is formed in the membrane. When the diaphragm is used in an electrolytic tank, protons in an anode can be migrated to a cathode, sulfate radicals and excessive protons in catholyte are ensured to be continuously electrolyzed to generate SO2 and water which are collected and utilized by a gas collecting tank, and meanwhile, a thallium-removing hydrogen-evolution cathode in a cathode chamber can adsorb harmful metals, so that the aim of removing the harmful metals is fulfilled. Therefore, the dual purposes of extracting sulfuric acid and removing thallium / arsenic from the ore leachate are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemistry and low-carbon metallurgy, and in particular to a proton exchange membrane, a preparation method, and a device and method for removing thallium / arsenic by extracting sulfuric acid from ore leaching solution. Background Art

[0002] In the process of metal mineral processing, sulfuric acid leaching is a widely used technical means. This method uses sulfuric acid as a leaching agent to treat ores containing various metals such as lithium, zinc, manganese, nickel, copper, gold, etc. under pressurized or normal pressure conditions, thereby achieving effective dissolution and release of metals. However, although this process can extract valuable metal components, it will cause some harmful metals such as thallium to dissolve into the solution together, forming a leachate containing high concentrations of sulfate and sulfuric acid. The presence of these harmful metals not only affects the subsequent purification and recovery efficiency of metals, but also poses a potential threat to the environment.

[0003] At present, for the harmful metals and acidic substances in such leachates, a large amount of alkaline substances are usually used for neutralization treatment, and the separation of different metals is achieved by a graded precipitation method. Although this method can effectively extract the required metals from the leachate, a large amount of heavy metal-containing waste residues will be generated during the treatment process. The generation of these waste residues not only increases the treatment cost, but may also cause secondary pollution problems due to the harmful metals remaining therein, especially when treating lean ores and difficult-to-leach metal ores (such as lithium mica mines), this situation is more serious. This not only increases the pressure of environmental governance, but also hinders the effective development and utilization of mineral resources and restricts the development of related areas.

[0004] In addition, traditional treatment processes are often unable to efficiently recycle sulfuric acid, resulting in a large amount of sulfuric acid being lost with the discharge of waste residues, further exacerbating the waste of resources. Therefore, there is an urgent need to develop a new technology that can effectively remove harmful metals (such as thallium) in the leachate and achieve effective recovery and recycling of sulfuric acid. This will not only help reduce the impact on the environment, but also improve resource utilization and promote the sustainable development of the mining industry. In response to this demand, research and development of more environmentally friendly and efficient leachate treatment technology has become a key issue that needs to be urgently addressed in the current mining field. Summary of the invention

[0005] In view of the problem that it is difficult to simultaneously remove harmful metals in ore leachate and recycle sulfuric acid, the present invention provides a proton exchange membrane with a high-efficiency proton transmission channel and a preparation method thereof. The proton exchange membrane has good mechanical properties, a high proton migration number and high proton conductivity, good corrosion resistance, and reduces production costs.

[0006] On the other hand, a device for removing thallium / arsenic by extracting sulfuric acid from ore leachate using the proton exchange membrane as a diaphragm and a method for removing thallium / arsenic by extracting sulfuric acid are provided. On the one hand, the harmful metal thallium / arsenic is precipitated out by the thallium removal hydrogen evolution cathode, and on the other hand, the proton exchange membrane is used to migrate the protons generated in the anode chamber to the cathode chamber, ensuring that sulfate ions and excess protons in the cathode liquid generate SO2 and water under the action of electrolysis and are collected by the cathode gas collecting tank, thereby achieving the dual purpose of extracting sulfuric acid and removing thallium / arsenic from the ore leachate.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic comprises the following steps:

[0009] S1: Mix cross-linked polyphenylene sulfide particles with hydrophilic functional groups on the surface, BaSO4 powder and high molecular polymer in an environment of <5°C, and send them into a high-speed shearing machine or a jet mill for fiberization treatment;

[0010] S2: After the fiberized powder is cooled to room temperature, it is poured into a mixer for granulation, and the granules are poured into a feeding system of a hot roller press, and rolled multiple times to form a film material;

[0011] S3: Soak the membrane material in sulfuric acid with a concentration of not less than 3 mol / L for at least 24 hours, take it out and dry it to obtain a selective permeable membrane for extracting sulfuric acid and removing thallium / arsenic.

[0012] Furthermore, the mass fraction ratio of the polyphenylene sulfide particles, the high molecular polymer and the BaSO4 powder is 10-90%: 1-10%: 10-90%.

[0013] Furthermore, the high molecular polymer is one or more of polytetrafluoroethylene, polyphenylene sulfide, polypropylene or polyethylene; and the D50 of the BaSO4 powder is 20nm-100μm.

[0014] The proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic prepared by any of the preparation methods described above is characterized in that the polyphenylene sulfide particles and BaSO4 powder in the proton exchange membrane are dispersed in a polymer support network formed by a high molecular polymer; the thickness of the polymer support network is 10-300μm; the polyphenylene sulfide particles are flat in the membrane, with a thickness of 1-10μm, and the extension direction of the flat surface is 5-20μm.

[0015] Furthermore, the proton transfer number of the proton exchange membrane is 0.7 to 0.95, and the proton conductivity is 20 to 200 mS / cm.

[0016] The device for extracting sulfuric acid and removing thallium / arsenic from ore leachate based on the above-mentioned proton exchange membrane is characterized in that it mainly includes an electrolytic cell, a cathode gas collecting tank and an anode gas collecting tank; the electrolytic cell uses the proton exchange membrane as a diaphragm, and includes an anode chamber and a cathode chamber separated by the diaphragm, the anode chamber is equipped with an inert anode and is used to accommodate an anode liquid, the cathode chamber is equipped with a thallium removal and hydrogen evolution cathode and is used to accommodate a cathode liquid, the cathode gas collecting tank is connected to the cathode chamber through a cathode gas collecting pipeline for storing SO2 and H2 produced by the cathode; the anode gas collecting tank is connected to the anode chamber through an anode gas collecting pipeline for storing O2 produced by the anode.

[0017] Further, the inert anode is composed of a substrate and an oxygen-evolving active substance attached to the substrate, the oxygen-evolving active substance is one or a mixture of oxygen-evolving metals selected from lead, silver, titanium, zirconium, ruthenium, iridium, tin, tantalum and oxides thereof, and preferably, the substrate is carbon paper;

[0018] The thallium removal hydrogen evolution cathode comprises a current collector and a carbon material attached to the surface of the current collector, wherein the carbon material is one of activated carbon, carbon fiber and graphene, and the current collector comprises one of stainless steel, titanium, nickel, graphite and carbon fiber felt.

[0019] Furthermore, the cathode gas collecting tank is connected to a gas separation device for separating SO2 and H2, the SO2 collecting pipeline is connected to the anode chamber, or a co-firing and collecting device is provided at the gas outlet of the cathode gas collecting tank.

[0020] The method for removing thallium / arsenic from ore leachate by extracting sulfuric acid and removing thallium / arsenic from ore leachate based on the device for removing thallium / arsenic from ore leachate by extracting sulfuric acid and removing thallium / arsenic from ore leachate according to any one of the above items is characterized in that the thallium-containing ore leachate is introduced into the cathode chamber as cathode liquid, the anode liquid is added into the anode chamber, the inert anode and the thallium removal hydrogen evolution cathode are respectively connected to the positive and negative electrodes of a DC power supply, a voltage of 1 to 5 V is applied, an oxygen evolution reaction occurs in the anode chamber to precipitate oxygen, and the thallium in the ore leachate is reduced to precipitate H2 in the cathode chamber. In this process, the protons generated in the oxygen evolution in the anode chamber migrate to the cathode chamber through the diaphragm, and the SO4 in the cathode chamber is reduced to precipitate H2. 2- It cannot migrate through the diaphragm to the anode chamber, causing protons to accumulate in the cathode chamber, and SO4 on the cathode carbon surface 2- The excess protons are electrolyzed to generate SO2 and water, that is, SO2 and H2 will be precipitated in the cathode chamber at the same time; the gases in the cathode chamber and the anode chamber are collected by the cathode gas collecting tank and the anode gas collecting tank respectively.

[0021] Further, the anolyte is a dilute sulfuric acid electrolyte having an acid concentration of 0-100 g / L;

[0022] The ore leaching solution is the ore leaching solution under pressurized or normal pressure conditions in metal hydrometallurgy, and the leaching solution contains SO4 2-The root concentration is 1-10 mol / L, and the pH value is below 1.5; the ore is one of lithium, zinc, manganese, nickel, copper, and gold;

[0023] Preferably, after the SO2 and H2 collected in the cathode gas collecting tank are separated by low-temperature pressurization, the SO2 is passed to the anode for electrochemical oxidation to generate sulfuric acid for reuse, and the cell pressure of the anode chamber is regulated to recover the separated H2; or the SO2 and H2 collected in the cathode gas collecting tank are directly co-fired to generate high-purity sulfuric acid.

[0024] The beneficial effects of the present invention are as follows:

[0025] The proton exchange membrane described in the present invention is mainly prepared by dispersing polyphenylene sulfide powder and BaSO4 powder in a polymer support network formed by a high molecular polymer. The membrane material is insoluble in acid and has good corrosion resistance. After being soaked in high-concentration acid, the sulfur site of polyphenylene sulfide undergoes dipole adsorption with proton hydrogen bonds and reaches a saturated state, and then tightly combines with the BaSO4 powder. The protons on the sulfur site can move along the adsorption site to form a continuous proton transfer path, thereby jointly constructing a nanoscale efficient proton transport channel in the membrane. The proton exchange membrane is manufactured using dry film forming technology and has high density, nanoscale transport channel characteristics, and the larger solvated SO4 2- Anions are difficult to migrate, thus forming a proton selective permeable membrane with a high proton migration number and high proton conductivity, ensuring high proton mobility and selectivity. In addition, the dry membrane technology has a simple manufacturing process, which significantly reduces production costs.

[0026] The present invention utilizes the polyphenylene sulfide-based proton exchange membrane as a diaphragm of an electrolysis device, ensuring that sulfate ions in the cathode chamber are retained on the cathode side during the electrochemical process, while protons generated by the electrochemical reaction in the anode chamber can migrate to the cathode through the diaphragm, so that there are excess protons in the cathode chamber. Under the action of electrolysis, sulfate ions and excess protons are continuously electrolyzed on the surface of the thallium removal hydrogen evolution cathode to generate SO2 and water, as shown in the following formula (1). At the same time, protons also undergo a reduction hydrogen evolution reaction on the surface of the thallium removal hydrogen evolution cathode, as shown in the following formula (2), so that the present invention can simultaneously realize the effective recovery of SO2 and H2.

[0027]

[0028] 2H + +2e - →H 2 (2)

[0029] During the electrochemical reaction, harmful metal ions such as thallium are adsorbed on the high specific surface area activated carbon surface of the cathode, thereby achieving the purpose of removing harmful metals. At the same time, for valuable metal ions such as aluminum, potassium and iron, their concentrations remain basically unchanged, which helps to maintain the value of these components in the final product.

[0030] The dilute sulfuric acid in the anode chamber undergoes an oxygen evolution reaction, as shown in formula (3), and the generated oxygen is introduced into the anode gas collecting tank through the anode gas collecting pipeline for recycling, thereby improving resource utilization.

[0031]

[0032] The present invention separates SO2 and H2, passes SO2 into the anode for electrochemical oxidation to generate sulfuric acid for reuse, and regulates the cell pressure of the anode chamber to recycle the separated H2, which helps to improve the overall energy utilization efficiency and reduce energy waste. Alternatively, SO2 and H2 collected in the cathode gas collecting tank are directly co-fired to generate high-purity sulfuric acid, which simplifies the process flow, reduces intermediate steps, and ensures the quality of sulfuric acid.

[0033] The present invention integrates the three links of hydrometallurgy, sulfuric acid production and hydrogen and oxygen preparation into one, thus improving the production efficiency of the whole system. The present invention not only solves the problems of acid extraction, slag reduction and thallium / arsenic removal, but also provides an additional function for the metallurgical plant - direct production of sulfuric acid and hydrogen, thus promoting the full utilization of resources and the diversified development of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a schematic diagram of the structure of the device for removing thallium and arsenic by extracting sulfuric acid from ore leachate.

[0035] Figure 2 This is the SEM image of the thallium-removing hydrogen evolution cathode in Example 1.

[0036] Figure 3 This is an EDX analysis diagram of particles deposited on the surface of the cathode for thallium removal and hydrogen evolution in Example 1.

[0037] The reference numerals are as follows:

[0038] 1- inert anode; 2- thallium removal and hydrogen evolution cathode; 3- diaphragm; 4- anode liquid; 5- cathode liquid; 6- cathode gas collecting pipeline; 7- cathode gas collecting tank; 8- anode gas collecting pipeline. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0040] The method for preparing a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic according to the present invention comprises the following steps:

[0041] S1: Mix cross-linked polyphenylene sulfide particles with hydrophilic functional groups on the surface, BaSO4 powder and high molecular polymer in an environment of <5°C, and send them into a high-speed shearing machine or a jet mill for fiberization. The mass fraction ratio of the polyphenylene sulfide particles, high molecular polymer and BaSO4 powder is 10-90%: 1-10%: 10-90%. The high molecular polymer is one or more of polytetrafluoroethylene, polyphenylene sulfide, polypropylene or polyethylene; the D50 of the BaSO4 powder is 20nm-100μm.

[0042] S2: After the fiberized powder is cooled to room temperature, it is poured into a mixer for granulation, and the granules are poured into the feeding system of a hot roller press, and rolled multiple times to form a film material. The cross-linked polyphenylene sulfide particles are flattened during the rolling process, and the thickness is 1-10 μm, and the extension on the flat surface is 5-20 μm.

[0043] S3: Soak the membrane material in sulfuric acid with a concentration of not less than 3 mol / L for at least 24 hours, take it out and dry it to obtain a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic. In the proton exchange membrane, the polyphenylene sulfide particles and BaSO4 powder are dispersed in a polymer support network formed by a high molecular polymer. The thickness of the polymer support network is 10-300 μm. The proton transfer number of the proton exchange membrane is 0.7-0.95, and the proton conductivity is 20-200 mS / cm.

[0044] After being soaked in high-concentration acid, the sulfur sites of polyphenylene sulfide and the proton hydrogen bonds undergo dipole adsorption and reach a saturated state. The proton-saturated surface of polyphenylene sulfide is tightly combined with the highly polar and super-hydrophilic surface of BaSO4 powder, jointly constructing an efficient proton transmission channel. Combined with the high density and nanoscale transport channel characteristics unique to dry film forming technology, the larger solvated SO4 2- Anions are difficult to migrate, thus forming a proton selective permeable membrane with high proton migration number and high proton conductivity. It should be noted that the role of polyphenylene sulfide is more ion selectivity, while BaSO4 powder provides ion transmission performance, so the ratio needs to be controlled. Too much BaSO4 powder will increase conductivity while reducing the proton migration number.

[0045] like Figure 1As shown, the device for removing thallium / arsenic by extracting sulfuric acid from ore leachate of the present invention mainly comprises an electrolytic cell, a cathode gas collecting tank 7 and an anode gas collecting tank (not shown in the figure). The electrolytic cell uses the above-mentioned proton exchange membrane as a diaphragm 3, and comprises an anode chamber and a cathode chamber separated by the diaphragm 3, the anode chamber is equipped with an inert anode 1 and is used to accommodate an anode liquid 4, the cathode chamber is equipped with a thallium removal hydrogen evolution cathode 2 and is used to accommodate a cathode liquid 5, and the cathode gas collecting tank 7 is connected to the cathode chamber through a cathode gas collecting pipeline 6 for storing SO2 and H2 produced by the cathode. The anode gas collecting tank is connected to the anode chamber through an anode gas collecting pipeline 8 for storing O2 produced by the anode.

[0046] The inert anode 1 is composed of carbon paper and an oxygen evolution active substance attached to the substrate, wherein the oxygen evolution active substance is one or a mixture of oxygen evolution metals selected from lead, silver, titanium, zirconium, ruthenium, iridium, tin, tantalum and oxides thereof.

[0047] The thallium removal hydrogen evolution cathode 2 comprises a current collector and a carbon material attached to the surface of the current collector, wherein the carbon material is one of activated carbon, carbon fiber, and graphene, and the current collector comprises one of stainless steel, titanium, nickel, graphite, and carbon fiber felt.

[0048] The cathode gas collecting tank 7 is connected to a gas separation device for separating SO2 and H2, and a SO2 collecting pipeline is connected to the anode chamber, or a co-firing and collecting device is provided at the gas outlet of the cathode gas collecting tank 7.

[0049] The method for removing thallium / arsenic by extracting sulfuric acid from ore leachate based on the above-mentioned device for removing thallium / arsenic by extracting sulfuric acid from ore leachate comprises the following steps: introducing thallium-containing ore leachate as cathode liquid 5 into the cathode chamber, adding anode liquid 4 into the anode chamber, connecting the inert anode 1 and the thallium removal hydrogen evolution cathode 2 to the positive and negative electrodes of a DC power supply respectively, applying a voltage of 1 to 5 V, an oxygen evolution reaction occurs in the anode chamber to precipitate oxygen, and thallium in the ore leachate is reduced to precipitate H2 in the cathode chamber. In this process, protons generated in the oxygen evolution in the anode chamber migrate to the cathode chamber through the diaphragm 3, and SO4 in the cathode chamber is reduced to precipitate H2. 2- It cannot migrate to the anode chamber through the diaphragm 3, causing protons to accumulate in the cathode chamber, and SO4 2- The excess protons are electrolyzed to generate SO2 and water, that is, SO2 and H2 are simultaneously precipitated in the cathode chamber; the gases in the cathode chamber and the anode chamber are collected by the cathode gas collecting tank 7 and the anode gas collecting tank, respectively.

[0050] The anolyte 4 is a dilute sulfuric acid electrolyte having an acid concentration of 0-100 g / L.

[0051] The ore leaching solution is the ore leaching solution under pressurized or normal pressure conditions in metal hydrometallurgy, and the leaching solution contains SO4 2-The root concentration is 1-10 mol / L, and the pH value is below 1.5; the ore is one of lithium, zinc, manganese, nickel, copper, and gold.

[0052] In order to better recycle SO2 and H2, the SO2 and H2 collected in the cathode gas collecting tank 7 are separated by low-temperature pressurization, and then SO2 is passed to the anode for electrochemical oxidation to generate sulfuric acid for reuse, and the cell pressure of the anode chamber is regulated to recycle the separated H2; or the SO2 and H2 collected in the cathode gas collecting tank 7 are directly co-fired to generate high-purity sulfuric acid.

[0053] The preparation method of the above-mentioned thallium removal hydrogen evolution cathode 2 is: rolling the carbon material into a film by a hot roller press, and then using a hot pressing composite process to thermally composite the film material with a single side of a current collector that has been carbonized and punched to prepare the thallium removal hydrogen evolution cathode 2. In the process of electrochemical acid extraction, harmful metal ions such as thallium will be adsorbed on the high specific surface area carbon surface of the cathode, thereby achieving the purpose of removing harmful metals.

[0054] Example 1

[0055] The method for preparing a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic described in this embodiment comprises the following steps:

[0056] S1: Mix cross-linked polyphenylene sulfide particles with hydrophilic functional groups on the surface, BaSO4 powder with D50=200nm and polytetrafluoroethylene (PTFE) in an environment of <5°C, and send them into a high-speed shearing machine or a jet mill for fiberization. The mass ratio of the cross-linked polyphenylene sulfide particles, BaSO4 powder and polytetrafluoroethylene is 50:42:8.

[0057] S2: After the fiberized powder is cooled to room temperature, it is poured into a mixer for granulation, and the granules are poured into the feeding system of a hot roller press, and rolled multiple times to form a film material.

[0058] S3: Soak the membrane material in sulfuric acid with a concentration of not less than 3 mol / L for at least 24 hours, take it out and dry it to obtain a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic. In the proton exchange membrane, polyphenylene sulfide particles and BaSO4 powder are dispersed in a polytetrafluoroethylene support network formed by polytetrafluoroethylene, and the thickness of the polytetrafluoroethylene support network is 250 μm. According to electrochemical measurement, the conductivity of the proton exchange membrane in a sulfuric acid solution with a concentration of 3 mol / L is 35 mS / cm, and the migration number is 0.92.

[0059] The proton exchange membrane prepared in this embodiment is used as the diaphragm 3 of the ore leachate sulfuric acid removal thallium / arsenic device. The ore leachate sulfuric acid removal thallium / arsenic device uses carbon paper and lead-titanium alloy attached to the carbon paper as the inert anode 1, and uses a dry electrode of carbon fiber composite titanium mesh as the thallium removal hydrogen evolution cathode 2. The ore leachate sulfuric acid removal thallium / arsenic device is used to treat the high-pressure sulfuric acid leachate of the lepidolite ore powder after flotation, and the leachate contains SO4 2- The concentration of the root is 3.46 mol / L, and the pH value is 0.15. A 0.1 mol dilute sulfuric acid electrolyte is introduced into the anode chamber as the anode liquid 4, and a high-pressure sulfuric acid leaching solution of lithium mica ore powder is introduced into the cathode chamber as the cathode liquid 5. The inert anode 1 and the thallium removal hydrogen evolution cathode 2 are respectively connected to the positive and negative electrodes of the DC power supply. A voltage of 4V is applied, and an oxygen evolution reaction occurs in the anode chamber to precipitate oxygen for recycling. A large amount of gas is generated on the surface of the carbon fiber cathode in the cathode chamber. After the gas passes through the fuchsin solution, the fuchsin fades, indicating that SO2 is generated. The cathode gas enters the gas storage tank for storage and subsequent separation and purification treatment. When the electrochemical sulfuric acid extraction is completed, the system is characterized and the pH value of the leachate is increased to 0.35. Table 1 shows the comparison of the metal ion components in the lithium mica leachate determined by ICP and the metal ion components in the leachate after acid extraction, and the SO4 determined by ion chromatography. 2- The changes in root concentrations are also listed in the table.

[0060] Table 1 Metal ions and SO4 in the lepidolite leachate before and after sulfuric acid extraction in Example 1 2- Root concentration comparison

[0061]

[0062] As can be seen from Table 1, in the electrochemical process of this embodiment, sulfate is consumed in large quantities, and Tl and As in the leachate cannot be detected after acid extraction, which proves that the device can effectively extract sulfuric acid and remove Tl and As in the ore leachate. At the same time, the content of metal ions such as Al, K, Fe, and Li is almost not lost.

[0063] Figure 2 This is a SEM image of the thallium removal hydrogen evolution cathode 2 described in this embodiment. As shown in the figure, there are deposited particles on the surface of the carbon fiber, and the deposited particles are analyzed by EDX. Figure 3 As shown, the deposited particles contain Al, Fe, and Tl, and the atomic percentage of Tl reaches 7.4%, indicating that this method can effectively remove Tl.

[0064] Example 2

[0065] The method for preparing a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic described in this embodiment comprises the following steps:

[0066] S1: Mix cross-linked polyphenylene sulfide particles with hydrophilic functional groups on the surface, BaSO4 powder with D50=5 μm and polytetrafluoroethylene (PTFE) in an environment of <5°C, and send them into a high-speed shearing machine or a jet mill for fiberization. The mass ratio of the cross-linked polyphenylene sulfide particles, BaSO4 powder and polytetrafluoroethylene is 32:60:8.

[0067] S2: After the fiberized powder is cooled to room temperature, it is poured into a mixer for granulation, and the granules are poured into the feeding system of a hot roller press, and rolled multiple times to form a film material.

[0068] S3: Soak the membrane material in sulfuric acid with a concentration of not less than 3 mol / L for at least 24 hours, take it out and dry it to obtain a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic. In the proton exchange membrane, polyphenylene sulfide particles and BaSO4 powder are dispersed in a polytetrafluoroethylene support network formed by polytetrafluoroethylene, and the thickness of the polytetrafluoroethylene support network is 250μm. According to electrochemical measurement, the conductivity of the proton exchange membrane in a sulfuric acid solution with a concentration of 3 mol / L is 47mS / cm, and the migration number is 0.83.

[0069] The proton exchange membrane prepared in this embodiment is used as the diaphragm 3 of the device for extracting sulfuric acid from ore leachate to remove thallium / arsenic. The device for extracting sulfuric acid from ore leachate to remove thallium / arsenic uses carbon paper and ruthenium-coated titanium alloy attached to the carbon paper as the inert anode 1, and uses a dry electrode of activated carbon composite titanium mesh as the cathode 2 for thallium removal and hydrogen evolution.

[0070] The ore leachate is used to extract sulfuric acid to remove thallium / arsenic. The high-pressure sulfuric acid leachate of zinc ore powder contains SO4 2- The concentration of the root is 1.53 mol / L, and the pH value is 0.6. A 0.1 mol dilute sulfuric acid electrolyte is introduced into the anode chamber as the anode liquid 4, and a high-pressure sulfuric acid leaching solution of zinc ore powder is introduced into the cathode chamber as the cathode liquid 5. The inert anode 1 and the thallium removal hydrogen evolution cathode 2 are respectively connected to the positive and negative electrodes of the DC power supply, and a 4V voltage is applied. An oxygen evolution reaction occurs in the anode chamber to precipitate oxygen for recycling, and a large amount of gas is generated on the surface of the carbon fiber cathode in the cathode chamber. After the gas passes through the fuchsin solution, the fuchsin fades, indicating that SO2 is generated. The cathode gas enters the gas storage tank for storage and subsequent separation and purification treatment; when the electrochemical sulfuric acid extraction is completed, the system is characterized, and the pH value of the leaching solution is increased to 1.15. SO4 in the leaching solution 2- When the concentration dropped to 1.15 mol / L, Tl in the extract could no longer be detected in ICP.

[0071] Example 3

[0072] The method for preparing a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic described in this embodiment comprises the following steps:

[0073] S1: Mix cross-linked polyphenylene sulfide particles with hydrophilic functional groups on the surface, BaSO4 powder with D50=5 μm and polytetrafluoroethylene (PTFE) in an environment of <5°C, and send them into a high-speed shearing machine or a jet mill for fiberization. The mass ratio of the cross-linked polyphenylene sulfide particles, BaSO4 powder and polytetrafluoroethylene is 45:47:8.

[0074] S2: After the fiberized powder is cooled to room temperature, it is poured into a mixer for granulation, and the granules are poured into the feeding system of a hot roller press, and rolled multiple times to form a film material.

[0075] S3: Soak the membrane material in sulfuric acid with a concentration of not less than 3 mol / L for at least 24 hours, take it out and dry it to obtain a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic. In the proton exchange membrane, polyphenylene sulfide particles and BaSO4 powder are dispersed in a polytetrafluoroethylene support network formed by polytetrafluoroethylene, and the thickness of the polytetrafluoroethylene support network is 270 μm. According to electrochemical measurement, the conductivity of the proton exchange membrane in a sulfuric acid solution with a concentration of 3 mol / L is 32 mS / cm, and the migration number is 0.91.

[0076] The proton exchange membrane prepared in this embodiment is used as the diaphragm 3 of the ore leachate sulfuric acid removal thallium / arsenic device. The ore leachate sulfuric acid removal thallium / arsenic device uses carbon paper and lead-silver alloy attached to the carbon paper as the inert anode 1, and uses a dry electrode of an activated carbon composite titanium mesh as the thallium removal hydrogen evolution cathode 2. The ore leachate sulfuric acid removal thallium / arsenic device is used to treat the high-pressure sulfuric acid leaching solution of manganese ore powder, and the leaching solution contains SO4 2- The concentration of the root is 2.68 mol / L, and the pH value is 0.25. A 0.1 mol dilute sulfuric acid electrolyte is introduced into the anode chamber as the anode liquid 4, and a high-pressure sulfuric acid leaching solution of manganese ore powder is introduced into the cathode chamber as the cathode liquid 5. The inert anode 1 and the thallium removal hydrogen evolution cathode 2 are respectively connected to the positive and negative poles of the DC power supply, and a voltage of 4V is applied. An oxygen evolution reaction occurs in the anode chamber to precipitate oxygen. After the gas generated in the cathode chamber passes through the fuchsin solution, the fuchsin fades, proving that SO2 is generated. When the electrochemical reaction is completed, the system is characterized, and the pH value of the leaching solution is raised to 0.78, and the SO4 in the leaching solution 2- When the concentration dropped to 1.27 mol / L, Tl in the extract could no longer be detected in ICP.

[0077] Example 4

[0078] The method for preparing a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic described in this embodiment comprises the following steps:

[0079] S1: Mix cross-linked polyphenylene sulfide particles with hydrophilic functional groups on the surface, BaSO4 powder with D50=5 μm and polytetrafluoroethylene (PTFE) in an environment of <5°C, and send them into a high-speed shearing machine or a jet mill for fiberization. The mass ratio of the cross-linked polyphenylene sulfide particles, BaSO4 powder and polytetrafluoroethylene is 65:27:8.

[0080] S2: After the fiberized powder is cooled to room temperature, it is poured into a mixer for granulation, and the granules are poured into the feeding system of a hot roller press, and rolled multiple times to form a film material.

[0081] S3: Soak the membrane material in sulfuric acid with a concentration of not less than 3 mol / L for at least 24 hours, take it out and dry it to obtain a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic. In the proton exchange membrane, polyphenylene sulfide particles and BaSO4 powder are dispersed in a polytetrafluoroethylene support network formed by polytetrafluoroethylene, and the thickness of the polytetrafluoroethylene support network is 270 μm. According to electrochemical measurement, the conductivity of the proton exchange membrane in a sulfuric acid solution with a concentration of 3 mol / L is 20 mS / cm, and the migration number is 0.95.

[0082] The proton exchange membrane prepared in this embodiment is used as the diaphragm 3 of the ore leachate sulfuric acid removal thallium / arsenic device. The ore leachate sulfuric acid removal thallium / arsenic device uses carbon paper and lead-silver alloy attached to the carbon paper as the inert anode 1, and uses a dry electrode of an activated carbon composite titanium mesh as the thallium removal hydrogen evolution cathode 2. The ore leachate sulfuric acid removal thallium / arsenic device is used to treat the high-pressure sulfuric acid leaching solution of laterite nickel ore powder, and the leaching solution contains SO4 2- The concentration of the root is 1.52 mol / L, and the pH value is 1.3. A 0.1 mol dilute sulfuric acid electrolyte is introduced into the anode chamber as the anode liquid 4, and a high-pressure sulfuric acid leaching solution of laterite nickel ore powder is introduced into the cathode chamber as the cathode liquid 5. The inert anode 1 and the thallium removal hydrogen evolution cathode 2 are respectively connected to the positive and negative poles of the DC power supply, and a voltage of 4V is applied. An oxygen evolution reaction occurs in the anode chamber to precipitate oxygen. After the gas generated in the cathode chamber passes through the fuchsin solution, the fuchsin fades, proving that SO2 is generated. When the electrochemical reaction is completed, the system is characterized, and the pH value of the leaching solution is increased to 1.58, and the SO4 in the leaching solution is 2- When the concentration dropped to 0.82 mol / L, Tl in the extract could no longer be detected in ICP.

[0083] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A method for preparing a proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic, characterized in that: The following steps are involved: S1: Mix cross-linked polyphenylene sulfide particles with hydrophilic functional groups on the surface, BaSO4 powder and high molecular polymer in an environment of <5°C, and send them into a high-speed shearing machine or a jet mill for fiberization treatment; S2: After the fiberized powder is cooled to room temperature, it is poured into a mixer for granulation, and the granules are poured into a feeding system of a hot roller press, and rolled multiple times to form a film material; S3: Soak the membrane material in sulfuric acid with a concentration of not less than 3 mol / L for at least 24 hours, take it out and dry it to obtain a selective permeable membrane for extracting sulfuric acid and removing thallium / arsenic.

2. The method for preparing a proton exchange membrane for removing thallium / arsenic from sulfuric acid according to claim 1, characterized in that: The mass fraction ratio of the polyphenylene sulfide particles, the high molecular polymer and the BaSO4 powder is 10-90%: 1-10%: 10-90%.

3. The method for preparing a proton exchange membrane for removing thallium / arsenic by extracting sulfuric acid according to claim 1, characterized in that: The high molecular polymer is one or more of polytetrafluoroethylene, polyphenylene sulfide, polypropylene or polyethylene; the D50 of the BaSO4 powder is 20nm-100μm.

4. The proton exchange membrane for extracting sulfuric acid and removing thallium / arsenic prepared by the preparation method according to any one of claims 1 to 3, characterized in that: The polyphenylene sulfide particles and BaSO4 powder in the proton exchange membrane are dispersed in a polymer support network formed by a high molecular polymer; the thickness of the polymer support network is 10-300 μm; the polyphenylene sulfide particles are flat in the membrane, with a thickness of 1-10 μm and an extension direction of the flat surface of 5-20 μm.

5. The proton exchange membrane according to claim 4, characterized in that: The proton transfer number of the proton exchange membrane is 0.7-0.95, and the proton conductivity is 20-200 mS / cm.

6. The device for removing thallium and arsenic from ore leachate by extracting sulfuric acid using the proton exchange membrane according to claim 4 or 5, characterized in that: The invention mainly comprises an electrolytic cell, a cathode gas collecting tank (7) and an anode gas collecting tank; the electrolytic cell uses the proton exchange membrane as a diaphragm (3), and comprises an anode chamber and a cathode chamber separated by the diaphragm (3); the anode chamber is provided with an inert anode (1) and is used to contain an anode liquid (4); the cathode chamber is provided with a thallium removal and hydrogen evolution cathode (2) and is used to contain a cathode liquid (5); the cathode gas collecting tank (7) is connected to the cathode chamber via a cathode gas collecting pipeline (6) and is used to store SO2 and H2 generated by the cathode; the anode gas collecting tank is connected to the anode chamber via an anode gas collecting pipeline and is used to store O2 generated by the anode.

7. The device for removing thallium and arsenic by extracting sulfuric acid from ore leachate according to claim 6, characterized in that: The inert anode (1) is composed of a substrate and an oxygen-evolving active substance attached to the substrate, wherein the oxygen-evolving active substance is one or a mixture of oxygen-evolving metals selected from the group consisting of lead, silver, titanium, zirconium, ruthenium, iridium, tin, tantalum and oxides thereof, and preferably, the substrate is carbon paper; The thallium removal hydrogen evolution cathode (2) comprises a current collector and a carbon material attached to the surface of the current collector, wherein the carbon material is one of activated carbon, carbon fiber and graphene, and the current collector comprises one of stainless steel, titanium, nickel, graphite and carbon fiber felt.

8. The device for removing thallium and arsenic by extracting sulfuric acid from ore leachate according to claim 6, characterized in that: The cathode gas collecting tank (7) is connected to a gas separation device for separating SO2 and H2, and the SO2 collecting pipeline is connected to the anode chamber, or a co-firing and collecting device is provided at the gas outlet of the cathode gas collecting tank (7).

9. A method for removing thallium / arsenic by extracting sulfuric acid from ore leachate based on the device for removing thallium / arsenic by extracting sulfuric acid from ore leachate according to any one of claims 6 to 8, characterized in that: The thallium-containing ore leachate is introduced as the cathode liquid (5) into the cathode chamber, the anode liquid is added into the anode chamber, the inert anode (1) and the thallium-removing hydrogen-evolving cathode (2) are respectively connected to the positive and negative electrodes of a DC power supply, and a voltage of 1 to 5 V is applied. An oxygen evolution reaction occurs in the anode chamber to precipitate oxygen, and the thallium in the ore leachate is reduced to precipitate H2 in the cathode chamber. In this process, the protons generated in the oxygen evolution in the anode chamber migrate to the cathode chamber through the diaphragm (3), and the SO4 in the cathode chamber is 2- It cannot migrate through the diaphragm (3) to the anode chamber, causing protons to accumulate in the cathode chamber, and SO4 2- The excess protons are electrolyzed to generate SO2 and water, that is, SO2 and H2 are simultaneously precipitated in the cathode chamber; the gases in the cathode chamber and the anode chamber are respectively collected by the cathode gas collecting tank (7) and the anode gas collecting tank.

10. The method for removing thallium / arsenic by extracting sulfuric acid from ore leachate according to claim 9, characterized in that: The anolyte (4) is a dilute sulfuric acid electrolyte having an acid concentration of 0-100 g / L; The ore leaching solution is the ore leaching solution under pressurized or normal pressure conditions in metal hydrometallurgy, and the leaching solution contains SO4 2- The root concentration is 1-10 mol / L, and the pH value is below 1.5; the ore is one of lithium, zinc, manganese, nickel, copper, and gold; Preferably, the SO2 and H2 collected in the cathode gas collecting tank (7) are separated by low-temperature pressurization, and then the SO2 is introduced into the anode for electrochemical oxidation to generate sulfuric acid for reuse, and the cell pressure of the anode chamber is regulated to recover the separated H2; or the SO2 and H2 collected in the cathode gas collecting tank (7) are directly co-fired to generate high-purity sulfuric acid.

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