CN101597776B - Metallurgy method of metal sulfide M1S - Google Patents

Abstract

The present invention relates to a metallurgical method of metal sulfide M ₁ S, the method uses ionic liquid M ₂ X as electrolyte, uses metal sulfide as solid cathode, or mixes powder or block of metal sulfide added with electronically conductive substance with The metal current collector composite is used as a solid cathode, and graphite or an inert anode is used as an anode, and the electrolysis is carried out in an inert atmosphere or in the air. The sulfide is electrochemically decomposed into metal products and elemental sulfur (S). The method has the advantages of simple process, low energy consumption and high added value of products, wherein the prepared metal materials such as metal tantalum powder, molybdenum powder, porous iron, etc. are nanometer metal powder materials or ultrafine metal powder materials or porous metal materials, which can be It can be directly used as hydrogen storage material, battery material, capacitor material, etc. or as a raw material for powder metallurgy.

Description

A metallurgical method for metal sulfide M1S

technical field

The invention belongs to the field of metallurgy, in particular to a metallurgical method for metal sulfides.

Background technique

Metal sulfide is another important basic mineral resource next to the abundance of oxides, and many commonly used non-ferrous metal mineral resources are even mainly sulfide. For example, copper sulfide ore accounts for 87%; lead-zinc ore mainly includes lead-zinc sulfide, lead sulfide, zinc sulfide and other ores; copper-nickel sulfide ore accounts for 84% of the total nickel reserves, and there are also some rare metal ores such as molybdenite Ore, tin ore, tellurium ore, etc. all belong to this type. However, the traditional metallurgical process of high-temperature calcination and thermal reduction of sulfides often has a long process, high energy consumption, and involves a large amount of SO ₂ and CO ₂ emissions. Therefore, the development of new technologies for metal sulfide ore smelting has always been paid attention to.

It is an ideal metallurgical idea to decompose metal sulfides into metal materials and elemental sulfur by electrochemical methods, in which metal sulfides can be used as anodes, cathodes or dissolved in electrolyte. Take the industrialization of NiS electrolysis to prepare metal Ni and elemental sulfur as an example: nickel sulfide is made into an anode and electrolyzed in an aqueous solution, and elemental sulfur and nickel ions are generated on the anode, and the latter are mass-transferred to the cathode to be electrodeposited into metallic nickel. But this approach cannot be generalized to other metal sulfides, which are inherently poor conductors.

The literature (Yunnan Metallurgy, 1995, 5, 30-33) reported that the PbS dissolved in the mixed ionic liquid of NaCl and KCl was directly electrolyzed to prepare metallic lead. The purity of cathode lead can be as high as 99.8%, and gaseous elemental sulfur is mainly precipitated on graphite anode. However, because the solubility of PbS in molten salt is too small, the reaction cannot proceed rapidly.

In the cathode scheme, literature (Journal of the Institute of Metals, 1961, 90, 6-12) reported that sulfur in molten copper cathodes can be removed in barium chloride molten salts. However, in this report, (1) the cathode is a liquid metal; (2) the content of sulfur as an impurity is limited.

The patent application (patent application No. 200610092501.2) discloses a method for removing the substance from the solid compound MX of substance X and metal or semimetal M, in order to remove the solid MX cathode in high temperature ionic liquids such as calcium chloride and barium chloride X in The patent application does not clearly express the anode product in the electrolysis process. At present, it seems that to realize this technology, graphite anode is still the most likely choice, and other anodes are either immature or costly. When X is O, the product on the graphite anode is mainly the compound CX of X and anode carbon instead of X, which not only deviates from the ideal expectation, but also causes a series of technical and cost difficulties due to the consumption of the anode. According to the literature (Electrochemistry Communications, 2007, 9, 1951-1957), _MoS2 was studied as solid cathode electrolytic desulfurization in _CaCl2 molten salt according to the patent. The complete electrolytic removal of elements will lead to low current efficiency and significant increase in energy consumption. In addition, XRD analysis revealed a large number of unidentifiable impurities in the cathode product besides elemental sulfur.

In order to use electrochemical methods to achieve electrometallurgy of sulfides in a highly efficient, energy-saving, environmentally friendly, and low-cost manner, it is necessary to comprehensively consider the cathodic process, the anode process, and the mass transfer process of sulfur ions in the ionic liquid during the electrolysis process, and try to use cheap and easy-to-use methods. The obtained electrolyte and electrode materials (such as graphite). For example, sulfur element in solid metal sulfide should be able to easily enter the ionic liquid and migrate to the anode for discharge. For the calcium chloride and barium chloride recommended in the patent application (patent application number 200610092501.2), since the solubility of calcium sulfide and barium sulfide is small, it is easy to deposit and form inclusions on the cathode. Appropriately increasing the electrolysis temperature will be beneficial to the dissolution of calcium sulfide and barium sulfide, but this measure will not only increase energy consumption, but also lead to easier discharge of graphite anode to generate CS ₂ .

Invention content:

The purpose of the present invention is to solve the above-mentioned deficiencies in the prior art by adopting medium and low temperature ionic liquid as electrolyte, and providing a metallurgical method for metal sulfide M ₁ S on this basis. The method either uses cheap medium-temperature ionic liquid electrolytes or low-temperature green ionic liquids, which can effectively decompose metal sulfides into metal materials and elemental sulfur at relatively low temperatures using solid metal sulfides as cathodes and graphite as anodes.

The technical solution provided by the present invention is: a metallurgical method of metal sulfide M ₁ S, using ionic liquid M ₂ X as electrolyte, using metal sulfide as solid cathode, or adding metal sulfide powder with electronically conductive substance Or blocks and metal current collectors are combined as solid cathodes, graphite or inert anodes are used as anodes, and electrolysis is performed in an inert atmosphere or air. The electrolysis temperature is controlled at 120-780 ° C. During electrolysis, the sulfur in the cathode enters the electrolyte in the form of ions And discharge at the anode to generate elemental sulfur, control the electrolysis time so that the electrolysis power reaches the theoretically required power and above, and electrochemically decompose the metal sulfide into metal products and elemental sulfur (S); the controlled electrolysis time makes the electrolysis power reach the theoretical required The theoretical power in the power demand and above refers to the required reduction power calculated according to Faraday's law when M ₁ S is reduced to M ₁ ;

The _M2 is at least one or more of Na ions, K ions, Al ions, R ₁ R ₂ R ₃ R ₄ N organic cations or R ₁ R ₂ R ₃ R ₄ P organic cations; the R ₁ , R ₂ , R ₃ , and R ₄ are organic groups containing 1-16 carbon atoms, H, F, Cl, Br, NO ₂ or NH ₂ , and said R ₁ , R ₂ , R ₃ and At least one of R ₄ is an organic group containing 1-16 carbon atoms; said X contains at least F, Cl, Br, OH, NO ₃ , CO ₃ , SO ₄ , PO ₄ , AlCl ₄ , PF ₆ , BF ₄ , SbF ₆ , CH ₃ COO, NTf ₂ , CF ₃ SO ₃ , CF ₃ CO ₂ , N(SO ₂ CF ₃ ) ₂ and other anions, one or more;

A mixed molten salt containing NaCl or KCl is selected as the electrolyte for the above-mentioned ionic liquid, the electrolysis temperature is controlled at 450-780° C., and the anode product is mainly gaseous elemental sulfur. The above-mentioned ionic liquid selects AlCl ₃ molten salt, nitrate molten salt, organic molten salt containing R ₁ R ₂ R ₃ R ₄ N or R ₁ R ₂ R ₃ R ₄ P cations or their mixed molten salt as the electrolyte, and the electrolysis temperature Controlled at 120-450°C, the anode product is mainly liquid elemental sulfur.

_M1 in the above metal sulfide _M1S is Ti, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Fe, Co, Ni, Mn, Cu, Zn, Si, Ge, Pb, Sn, One of Ag, Au, Pt, Pd, Rh, Ir, Ru, Os, Re, Al, B, Ga, In, Tl, Te, Sb, Bi, Sc, Y, U, lanthanides, actinides or various;

The above-mentioned metal sulfides are sulfides of a single metal element, or a combination of sulfides of two or more metal elements; the combination of sulfides of two or more metal elements is a mixture or a composite metal sulfide.

The aforementioned metal products are pure metals, semi-metals, alloys, intermetallic compounds or metal mixtures as well as combinations of metals with added conductive materials.

The basic particle size of the above metal products is 1 nanometer-100 micrometers, and they are powder or porous materials.

The above-mentioned elemental sulfur (S) is liquid or gaseous, and can be separated from the ionic liquid electrolyte, and can be separated, extracted, and condensed into solid elemental sulfur from the electrolytic cell during or after electrolysis.

The above-mentioned electrolysis can adopt the control tank pressure mode (constant tank pressure or variable tank pressure), control current mode (constant current or variable current) or control potential mode.

When the above-mentioned electrolysis is carried out at a relatively high temperature (above 400°C), it is generally carried out under the protection of an inert gas, which is stable during the high-temperature molten salt electrolysis process, preferably high-purity argon. When the above-mentioned electrolysis is carried out at a relatively low temperature (120° C. to 400° C.), it can be carried out directly in an air atmosphere.

After the above-mentioned metal product is taken out, it is cooled to normal temperature in an inert atmosphere or air, and then washed in water, dilute inorganic acid (such as nitric acid, hydrochloric acid, sulfuric acid, hydrofluoric acid, hydrogen peroxide or any combination thereof) or organic solvent , to obtain metallic materials after drying in the atmosphere or in vacuum.

The above-mentioned metal sulfides are powders, or porous or dense sulfide blocks, and their combination with the metal current collector can be point contact, surface contact or three-dimensional network contact (before combining with the metal current collector, it can also be in the metal sulfide Add other electronically conductive materials such as metals, carbon, conductive ceramics, etc. beforehand).

In the above electrolysis process, the cathode chamber and the anode chamber can also be separated by a diaphragm that allows ions to pass through. Its purpose is to limit the mass transfer of anode products to the cathode.

After the electrolysis process is completed, the metal product can be taken out of the molten salt along with the working electrode. If necessary, a new sulfide solid cathode can be placed in the molten salt to start a new round of electrolysis, thereby realizing the continuous production of metal materials.

The present invention adopts a lower electrolysis temperature, thereby facilitating the production of nanometer-sized metal particles. These metal materials can be directly used as hydrogen storage materials, battery materials, capacitor materials, etc. or as raw materials for powder metallurgy, etc.

The invention has the advantages of low energy consumption, high electrolysis efficiency, short production process, less pollution, simple process and high added value of products due to the low electrolysis temperature.

Invention principle:

Compared with the prior art, the present invention mainly finds through experiments that NaCl, KCl, etc. and their mixed salts have better solubility to sulfur ions. If it is used as an ionic liquid electrolyte, the temperature of the electrolysis reaction can be significantly reduced and the electrolysis reaction can be improved. The speed of the reaction, so as to achieve the purpose of decomposing the metal sulfide into metal and elemental sulfur with high efficiency and low energy consumption. The chemical basis of the invention is:

Ideal expectations for sulphide metallurgy:

Cathode reaction: M ₁ S (solid) + 2e = M1 (solid) + S ^2- (1)

Anode reaction: S ^2- -2e=S (gas or liquid) (2)

Total reaction: M ₁ S (solid) = M ₁ (solid) + S (gas or liquid)

For graphite anodes, the following side reactions may occur:

C+2S ^2- -4e＝CS ₂ (gas) (3)

Reducing the reaction temperature can avoid the occurrence of side reaction (3), but because the efficient progress of (1) and (2) reactions depends on the rapid migration of sulfide ions in the ionic liquid electrolyte, this requires the ionic liquid electrolyte to have higher solubility. If CaCl ₂ and BaCl ₂ are used as the ionic liquid, the reaction rate is reduced due to the low solubility of CaS, BaS, etc. in the molten salt, or it can only be carried out at a higher temperature or the formation of CaS, BaS, etc. in the metal product These are obviously deviated from the ideal expectations of sulfide metallurgy. In NaCl, KCl and other ionic liquids, Na ₂ S, K ₂ S, etc. have high solubility, so that the electrolysis reaction can be carried out quickly at a lower temperature as expected, and the metal products are not easy to form sulfide inclusions , It is also beneficial to the washing of metal products after electrolysis is completed. In contrast, LiCl should be avoided as the main ionic liquid due to its high price.

Although currently there is no inert anode in this technical field that can compare with graphite anode in terms of cost performance, the present invention does not exclude the use of inert anode in the future. If an inert anode is used, the electrolysis temperature may be allowed to rise further, but even so, NaCl, KCl, etc. are better choices than _CaCl2 , _BaCl2 , LiCl, etc. It must be pointed out that high electrolysis temperature means large heat loss and high vapor pressure of molten salt, which are unfavorable to electrolysis reaction.

The invention also discloses that when the anode product is liquid elemental sulfur, the electrolysis reaction can be carried out at a lower temperature or even close to room temperature, thereby significantly reducing electrolysis equipment and operating costs.

Description of drawings:

Fig. 1 is the SEM image of the molybdenum electrolysis product of the embodiment of the present invention.

Fig. 2 is the XRD pattern of the electrolysis product iron in the embodiment of the present invention.

Fig. 3 is an XRD pattern of the molybdenum electrolysis product in the embodiment of the present invention.

Fig. 4 is the XRD pattern of the anode product S generated in the embodiment of the present invention.

Detailed ways:

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. These descriptions are only for further illustrating the present invention, rather than limiting the present invention.

In the present invention, the sulfide raw material can be prepared into a porous block of a specific size by mechanical pressure or casting method. After dehydration or sintering in the air or inert atmosphere at 100-1500 ° C, the porosity of the obtained sulfide block is about 0- 80%.

The ionic liquid electrolyte used in the present invention includes NaNO ₃ , KNO ₃ , NaCl, KCl, AlCl ₃ , KF, BMIMPF ₆ and the like, which are dehydrated, dried and impurity-removed. During electrolysis, the sulfide powder or block is combined with a conductive cathode current collector as a solid cathode. The current collector material is a metal conductive material, and wires, sheets, nets, baskets, etc. of iron, molybdenum, tungsten or tantalum can be selected. The anode is made of graphite, and the electrolysis is carried out under the protection of an inert atmosphere or in the air, and the electrolysis time is generally 0.5-40 hours.

After the electrolysis product is taken out, it is washed in water, an organic solvent, and an inorganic acid, and then conventionally or vacuum-dried.

Embodiments of the present invention are described in detail below.

Example 1:

About 0.5-2g of commercially available MoS2 powder is compressed into a sulfide test piece with a diameter of about 20mm and a thickness of 0.5-1.5mm by mechanical pressure at 0.5-10MPa, and dried in air at 200°C for 0.5-8 hours. The porosity is 20-80%. The sulfide test piece and the conductive cathode current collector are combined as the working electrode, the graphite rod is used as the counter electrode, and the graphite electrode is separated from the gas phase of the electrolytic cell by a quartz tube to export the anode product. Molten KCl+NaCl is used as the electrolyte, in an argon environment, the temperature is 680 and 750°C, and the electrolysis voltage is controlled at 1.2-2.4V. After 30, 60, 120, 180, and 300 minutes of electrolysis, the metal product was taken out and washed and dried with water. The SEM of the obtained metal product molybdenum is shown in Figure 1. As can be seen from Figure 1, the obtained metal has a basic particle size of 30 -80 nanometer particles, the XRD of the metal product molybdenum is shown in Figure 3, as can be seen from Figure 3, the obtained molybdenum is a pure metal; the anode product is gaseous elemental sulfur. The XRD of the anode product sulfur is shown in Figure 4, and it can be seen from Figure 4 that the obtained sulfur is pure elemental sulfur.

Example 2:

About 2g of commercially available FeS blocks, with a porosity of basically 0, are combined with a conductive cathode current collector as a working electrode, and a graphite rod is used as a counter electrode, and a quartz tube is used to separate the graphite electrode from the gas phase of the electrolytic cell to export the anode product . Using molten KCl+NaCl as the electrolyte, in an argon atmosphere, the temperature is 680°C, and the electrolysis voltage is controlled at 1.2-2.4V. After electrolysis for 30, 60, 120, 180, and 300 minutes respectively, the metal product is taken out and washed and dried to obtain porous iron with a basic particle size of 5-50 microns. The XRD of the obtained product iron is shown in Figure 2, and it can be seen from Figure 2 that the obtained iron is a pure metal; the anode product is gaseous elemental sulfur.

Example 3:

Mix about 0.5-2g of Ti ₂ S ₃ powder and FeS powder weighed in proportion, mix them evenly through mechanical ball milling, press them into sulfide test pieces with a diameter of about 20mm at 0.5-10MPa, and dry them in air at 200°C for 0.5-8 Hours, the porosity of the obtained sample is between 20% and 80%. The sulfide test piece and the conductive cathode current collector are combined as the working electrode, the graphite rod is used as the counter electrode, and the graphite electrode is separated from the gas phase of the electrolytic cell by a quartz tube to export the anode product. Using molten KCl+KF as the electrolyte, in an argon atmosphere, the temperature is 650°C, and the electrolysis voltage is controlled at 2.4-3.2V. After 240-900 minutes of electrolysis, the metal product is taken out and washed and dried to obtain a TiFe alloy. The anode product is gaseous elemental sulfur.

Example 4:

About 2g of commercially available FeS blocks, with a porosity of basically 0, are combined with a conductive cathode current collector as a working electrode, and a graphite rod is used as a counter electrode, and a quartz tube is used to separate the graphite electrode from the gas phase of the electrolytic cell to export the anode product . Using molten KCl+NaCl+CsCl as the electrolyte, in an argon atmosphere, the temperature is 550°C, and the electrolysis voltage is controlled at 1.4-2.4V. After electrolysis for 30, 60, 120, 180, and 300 minutes respectively, the metal product is taken out and washed and dried to obtain porous iron with a basic particle size of 1-50 microns. The anode product is gaseous elemental sulfur.

Example 5:

About 0.5-2g of commercially available TaS ₂ powder is compressed into a sulfide test piece with a diameter of about 20mm and a thickness of 1.3-1.5mm by mechanical pressure at 0.5-10MPa, and dried in air at 200°C for 0.5-8 hours to obtain a sample The porosity is between 20% and 80%. The sulfide test piece and the conductive cathode current collector are combined as the working electrode, the graphite rod is used as the counter electrode, and the graphite electrode is separated from the gas phase of the electrolytic cell by a quartz tube to export the anode product. Molten KCl+NaCl+CsCl is used as the electrolyte, in an argon atmosphere, the temperature is 550 and 680°C, and the electrolysis voltage is controlled at 2.2-3.0V. After electrolysis for 180, 300, and 600 minutes respectively, the metal product was taken out and washed with water and dried to obtain nano-tantalum powder with a basic particle size of about 50 nanometers. The anode product is gaseous elemental sulfur.

Embodiment 6:

About 0.5-2g of commercially available Cu ₂ S powder is compressed into a sulfide test piece with a diameter of about 20mm by mechanical pressure at 0.5-10MPa, and dried in air at 200°C for 0.5-8 hours. The porosity of the obtained sample is 20-80 %. Combine the sulfide test piece and the conductive cathode current collector as the working electrode, use the graphite rod as the counter electrode, and cover the graphite electrode with a quartz tube whose inner diameter is about 2cm larger than that of the graphite electrode, wherein the lower end of the quartz tube is flush with the graphite electrode Or slightly lower, the upper end is above the electrolyte page. The molten NaNO ₃ +LiNO ₃ +LiCl is used as the electrolyte, the temperature is 250 and 350°C, and the electrolysis voltage is controlled at 0.5-1.5V. After 120-600 minutes of electrolysis, the metal product is taken out and washed with water and dried to obtain metal copper powder. The anode product is liquid elemental sulfur.

Embodiment 7:

About 0.5-2g of commercially available MoS ₂ powder is compressed into a sulfide test piece with a diameter of about 20mm by mechanical pressure at 0.5-10MPa, and dried in air at 200°C for 0.5-8 hours. The porosity of the obtained sample is 20-80%. Combine the sulfide test piece and the conductive cathode current collector as the working electrode, use the graphite rod as the counter electrode, and cover the graphite electrode with a quartz tube whose inner diameter is about 2cm larger than that of the graphite electrode, wherein the lower end of the quartz tube is flush with the graphite electrode Or slightly lower, the upper end is above the liquid level of the electrolyte. The molten KCl+LiCl+LiF is used as the electrolyte, the temperature is 400°C, and the electrolysis voltage is controlled at 1.8-2.5V. After 120 to 600 minutes of electrolysis, the metal product is taken out and washed with water and dried to obtain nanomolybdenum powder with a basic particle size of about 50 nanometers. The anode product is mainly liquid elemental sulfur.

Embodiment 8:

About 0.5-2g of commercially available PbS powder is compressed into a sulfide test piece with a diameter of about 20mm by mechanical pressure at 0.5-10MPa, and dried in air at 200°C for 0.5-8 hours. The porosity of the obtained sample is 20-80%. Combine the sulfide test piece with the conductive cathode current collector as the working electrode, use the graphite rod as the counter electrode, and cover the graphite electrode with a quartz tube with an inner diameter about 2 cm larger than the graphite electrode, wherein the lower end of the quartz tube is flush with the graphite electrode Or slightly lower, the upper end is above the liquid level of the electrolyte. Use molten NaCl+AlCl ₃ as the electrolyte, the temperature is 200°C, 0.5-1.5V. After 120-600 minutes of electrolysis, the metal product is taken out, washed with water and dried to obtain metal lead powder. The anode product is liquid elemental sulfur.

Embodiment 9:

About 0.5-1g of commercially available Cu2S powder is compressed into a sulfide test piece with a diameter of about 20mm by a mechanical pressure of 0.5-10MPa, and dried in air at 200°C for 0.5-8 hours. The porosity of the obtained sample is 20-80%. The sulfide test piece and the conductive cathode current collector are combined as the working electrode, and the graphite rod is used as the counter electrode. The molten BMIMPF ₆ was used as the electrolyte, the temperature was 150°C, and the electrolysis voltage was controlled at 0.5-1.5V. After 120-600 minutes of electrolysis, the metal product is taken out and washed with water and dried to obtain metal copper powder. The liquid elemental sulfur produced by the anode sinks to the bottom of the container.

Claims (8)

1. metal sulfide M ₁The metallurgical method of S is characterized in that: with ionic liquid M ₂X is an ionogen; Metallic sulfide is compound as solid state cathode as solid state cathode and metal collector, make anode with graphite or inert anode, in inert atmosphere or air, carry out electrolysis; Electrolysis temperature is controlled at 120-780 ℃; Sulphur during electrolysis in the negative electrode gets into electrolytic solution and generates elemental sulfur at anode discharge with the ionic form, the control electrolysis time make electrolysis electricity reach theoretical required electric weight and more than, be metallic product and elemental sulfur (S) with the metallic sulfide electrochemical decomposition;

Said control electrolysis time make electrolysis electricity reach theoretical required electric weight and above in theoretical electric weight, be meant M ₁S is reduced into M ₁The time, calculate needed reduction electric weight according to Faraday's law;

Said M ₂For comprising Na ion, K ion, Al ion, R at least ₁R ₂R ₃R ₄N organic cation or R ₁R ₂R ₃R ₄In the P organic cation one or more;

Said organic cation is BMIMPF ₆

Said X comprises F, Cl, Br, OH, NO at least ₃, CO ₃, SO ₄, PO ₄, AlCl ₄, PF ₆, BF ₄, SbF ₆, CH ₃COO, NTf ₂, CF ₃SO ₃, CF ₃CO ₂, N (SO ₂CF ₃) ₂A kind of or two or more in the negatively charged ion;

Said metal sulfide M ₁M among the S ₁Be among Ti, Zr, Hf, Cr, Mo, W, V, Nb, Ta, Fe, Co, Ni, Mn, Cu, Zn, Si, Ge, Pb, Sn, Ag, Au, Pt, Pd, Rh, Ir, Ru, Os, Re, Al, B, Ga, In, Tl, Te, Sb, the Bi one or more.

2. like claim 1,2 or 3 described metal sulfide Ms ₁The metallurgical method of S is characterized in that: said metallic product is pure metal, semi-metal; The ultimate particle of said metallic product is of a size of 1 nanometer-100 micron, is powder or porous materials.

3. metal sulfide M as claimed in claim 1 ₁The metallurgical method of S is characterized in that: said elemental sulfur (S) can be separated with il electrolyte for liquid or gaseous state, can from electrolyzer, separate, draw, be condensed into solid-state elemental sulfur in the electrolytic process or after the electrolysis completion.

4. metal sulfide M as claimed in claim 1 ₁The metallurgical method of S is characterized in that: control flume die pressing type, control current pattern or CONTROLLED POTENTIAL pattern are adopted in said electrolysis; Electrolysis will be carried out under protection of inert gas when carrying out more than 400 ℃; Said rare gas element is a high-purity argon gas.

5. metal sulfide M as claimed in claim 1 ₁The metallurgical method of S is characterized in that: said metallic product is cooled to normal temperature after taking out in inert atmosphere or air, in water, rare mineral acid or organic solvent, washs then, in atmosphere or vacuum, obtains metallic substance after the drying.

6. metal sulfide M as claimed in claim 1 ₁The metallurgical method of S is characterized in that: said metallic sulfide is powder or porous or fine and close sulfide piece, its with the combination of metal collector be some contact, face contacts perhaps three-dimensional netted contact.

7. metal sulfide M as claimed in claim 1 ₁The metallurgical method of S is characterized in that: in the electrolytic process, also adopted the barrier film that allows ion to pass through that cathode compartment and anolyte compartment are isolated.

8. metal sulfide M as claimed in claim 1 ₁The metallurgical method of S is characterized in that: the fused salt mixt that said ionic liquid is selected to comprise NaCl or KCl is as ionogen, and electrolysis temperature is controlled at 450-780 ℃, and anodic product is mainly gaseous elemental sulphur; Said ionic liquid is selected AlCl ₃Fused salt, nitrate salt fused salt, BMIMPF ₆Cationic organism fused salt or their mixed fused salt are as ionogen, and electrolysis temperature is controlled at 120-450 ℃, and anodic product is mainly liquid elemental sulfur.

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