JP6036126B2 - Method for producing tungsten oxide and method for producing tungsten - Google Patents

Description

  The present invention relates to a method for producing tungsten oxide and a method for producing tungsten.

  Patent Document 1 describes a method of recovering tungsten from scraps such as tools. In this method, sodium tungstate is obtained by dissolving scrap with sodium nitrate. This sodium tungstate is converted to ammonium tungstate. Thereafter, tungsten carbide is recovered.

  Patent Document 2 describes a method for producing an ammonium tungstate aqueous solution. This method includes a step of bringing an alkali metal tungstate aqueous solution having a pH of 9 to 14 and containing impurities into contact with an anion exchange resin, and a step of bringing a low concentration anion containing solution into contact with the anion exchange resin. , Including.

  Non-Patent Document 1 describes the recovery of rare metals. In this collection, the coating layer of the coating chip is removed.

JP 2010-208909 A JP 2011-184220 A

2007 Development of technology for rationalizing energy use Development project for highly efficient recovery system for rare metals, etc. Result report P242-243

  By the way, when collecting rare metals, chlorine gas may be released into the atmosphere. When the amount of released chlorine gas increases, there is a risk of causing a problem that the environmental load increases.

  The present invention has been made to solve the above-described problems, and provides a method for producing tungsten oxide and a method for producing tungsten that can reduce the amount of chlorine gas released and reduce the environmental load. Objective.

  The method for producing tungsten oxide according to the present invention includes a first step in which tungsten carbide containing impurities is exposed to a heated atmosphere of a process gas containing chlorine gas to produce chlorides of the impurities and tungsten chloride. A second step of separating the tungsten chloride from the mixed gas containing tungsten chloride and chlorine gas; and a third step of oxidizing the tungsten chloride and generating tungsten oxide and chlorine gas after separating the tungsten chloride. And a fourth step of separating the chlorine gas from the tungsten oxide and chlorine gas to obtain the tungsten oxide, wherein the chlorine gas separated in the fourth step is used in the first step. It is done.

  In this manufacturing method, impurity chloride is generated and tungsten chloride is generated in the first step. Subsequently, tungsten chloride is separated from the mixed gas containing tungsten chloride and chlorine gas, and the separated tungsten chloride is oxidized to produce tungsten oxide and chlorine gas. And chlorine gas is isolate | separated from tungsten oxide and chlorine gas. The separated chlorine gas is used in the first step. Therefore, according to this manufacturing method, by using the separated chlorine gas again, the amount of released chlorine gas is reduced, so that the environmental load can be reduced.

  In the first step of the manufacturing method according to the present invention, the chlorine gas and the tungsten carbide containing the impurity are heated at a temperature lower than the boiling point of the impurity chloride. In the temperature range below the boiling point of the impurity chloride, the impurity chloride becomes a liquid or solid, so that the impurity chloride can be condensed or solidified to easily remove the condensed or solidified impurity chloride. it can.

  In the manufacturing method according to the present invention, the process gas is a mixed gas of chlorine gas and an inert gas, or chlorine gas. In the first step, the tungsten carbide is 750 ° C. or higher and 1000 ° C. or lower. Heated at temperature. When tungsten carbide containing impurities is heated at a temperature of 750 ° C. or higher and 1000 ° C. or lower in a mixed gas of chlorine gas and inert gas, or chlorine gas, generation of impurity chlorides is promoted.

  In the manufacturing method according to the present invention, in the first step, the chloride is a liquid. When the impurity chloride is liquid, the impurity chloride can be easily separated from gaseous tungsten chloride.

  In the manufacturing method according to the present invention, the impurity is cobalt. Thus, even when the impurity is cobalt, the amount of chlorine gas released is reduced and the environmental load can be reduced.

  In the method for producing tungsten according to the present invention, a first step of producing a chloride of impurities and tungsten chloride by exposing tungsten carbide containing impurities in a heating atmosphere of a process gas containing chlorine gas; A second step of separating the tungsten chloride from the mixed gas containing tungsten chloride and the chlorine gas; and a third step of reducing the tungsten chloride and then producing tungsten and hydrochloric acid gas after separating the tungsten chloride. A fourth step of separating the hydrochloric acid gas from the tungsten and hydrochloric acid gas to obtain the tungsten, and a fifth step of separating the hydrochloric acid gas and then heating the hydrochloric acid gas and silicon to produce silicon chloride. A sixth step of heating the silicon chloride and oxygen to produce silicon oxide and chlorine gas; and Of silicon and separating the chlorine gas from the chlorine gas, the comprises a seventh step of obtaining a silicon oxide, wherein the seventh step in the separated chlorine gas is used in the first step.

  In this manufacturing method, impurity chloride and tungsten chloride are generated in the first step. Subsequently, tungsten chloride is separated from the mixed gas containing tungsten chloride and chlorine gas, and the separated tungsten chloride is reduced to produce tungsten and hydrochloric acid gas. Then, after separating the hydrochloric acid gas, the separated hydrochloric acid gas and silicon are heated to produce silicon chloride, and then the silicon chloride and oxygen are heated to produce silicon oxide and chlorine gas. This chlorine gas is used in the first step. Therefore, according to this manufacturing method, the amount of released chlorine gas is reduced by reusing the generated chlorine gas, so that the environmental load can be reduced.

  In the first step of the manufacturing method according to the present invention, the chlorine gas and the tungsten carbide containing the impurity are heated at a temperature lower than the boiling point of the impurity chloride. In the temperature range below the boiling point of the impurity chloride, the impurity chloride becomes a liquid or solid, so that the impurity chloride can be condensed or solidified to easily remove the condensed or solidified impurity chloride. it can.

  In the manufacturing method according to the present invention, the process gas is a mixed gas of chlorine gas and an inert gas, or chlorine gas. In the first step, the tungsten carbide is 750 ° C. or higher and 1000 ° C. or lower. Heated at temperature. When tungsten carbide containing impurities is heated at a temperature of 750 ° C. or higher and 1000 ° C. or lower in a mixed gas of chlorine gas and inert gas, or chlorine gas, generation of impurity chlorides is promoted.

  In the manufacturing method according to the present invention, in the first step, the chloride is a liquid. When the impurity chloride is liquid, the impurity chloride can be easily separated from gaseous tungsten chloride.

  In the manufacturing method according to the present invention, the impurity is cobalt. Thus, even when the impurity is cobalt, the amount of chlorine gas released is reduced and the environmental load can be reduced.

  According to the present invention, the amount of chlorine gas released can be reduced, and the environmental load can be reduced.

It is a figure showing a process of a manufacturing method of tungsten oxide concerning one embodiment. It is a figure showing a process of a manufacturing method of tungsten oxide concerning one embodiment. It is a figure which shows roughly the structure of the processing apparatus used with the manufacturing method of tungsten oxide which concerns on one Embodiment. It is a figure which simplifies and shows the structure of an oxidation reaction apparatus. It is a figure which simplifies and shows the structure of an oxygen removal apparatus. It is a figure which shows the process of the manufacturing method of tungsten which concerns on one Embodiment. It is a figure which shows the process of the manufacturing method of tungsten which concerns on one Embodiment. It is a figure which simplifies and shows the structure of a reduction reaction apparatus. It is a figure which shows roughly the structure of the processing apparatus used with the manufacturing method of tungsten which concerns on one Embodiment. It is a figure which simplifies and shows the structure of an oxidation reaction apparatus.

  Hereinafter, an embodiment of a method for producing tungsten oxide according to the present invention will be described as a first embodiment with reference to the accompanying drawings, and an embodiment of a method for producing tungsten according to the present invention will be described as a second embodiment.

  In the tungsten oxide manufacturing method of the first embodiment, tungsten oxide is manufactured after removing impurities from tungsten carbide containing impurities. Here, as the tungsten carbide containing impurities, for example, a tungsten tool containing metallic cobalt as impurities can be cited. The surface of the tungsten tool is coated with a titanium compound such as titanium nitride (TiN). Below, the process of manufacturing tungsten oxide from this tungsten tool will be described.

  1 and 2 are diagrams showing main steps of the tungsten oxide manufacturing method according to the present embodiment. Step S1 (first step) is a step of heat-treating tungsten carbide containing impurities in chlorine gas. In step S1, tungsten carbide containing impurities is exposed to a heated atmosphere of a process gas containing chlorine gas to produce impurity chlorides and tungsten chloride.

  Step S1 is performed, for example, in the reaction furnace 11 of the processing apparatus 10 shown in FIG. The processing apparatus 10 includes a reaction furnace 11, a cooling trap 12, and a storage tank 13. The reaction furnace 11 includes a mounting shelf 11a having a plurality of steps. The mounting shelf 11a is supported by being suspended by a support bar 11b. On the mounting shelf 11a, an object to be processed M1, which is a tungsten carbide tool containing, for example, 14% cobalt, is placed on each step portion in a state where the tool is crushed.

  The reaction furnace 11 is provided with a gas introduction port 11c. The process gas G1 is supplied to the reaction furnace 11 from the gas inlet 11c. The process gas G1 is a mixed gas of chlorine gas and inert gas, or substantially 100% chlorine gas. As the inert gas, for example, nitrogen, helium, argon, neon, xenon, or the like can be used. Specifically, for example, 500 ml / min of chlorine gas and 5000 ml / min of nitrogen are supplied to the reactor 11. Moreover, the reaction furnace 11 has a heater 11d provided so as to surround the mounting shelf 11a. By this heater 11d, the atmosphere containing chlorine gas around the workpiece M1 is heated to, for example, 1000 ° C. The reaction furnace 11 is provided with a gas discharge port 11e.

  The reaction furnace 11 in which step S1 is executed has been described above. However, the apparatus for executing the step S1 is not limited to the reaction furnace 11, and various apparatuses can be used. Below, the reaction process of the to-be-processed object M1 in the case of using the reaction furnace 11 is demonstrated.

First, the workpiece M1 is placed on each step of the placement shelf 11a. Next, the process gas G1 is heated using the heater 11d while supplying the process gas G1 into the reaction furnace 11 from the gas inlet 11c. For example, the workpiece M1 is exposed in a heated atmosphere of 1000 ° C. for 2 hours. By this heating, the titanium nitride coated on the workpiece M1 is etched with chlorine gas before step S1. At this time, gaseous titanium chloride and nitrogen are produced as gas. The titanium chloride and nitrogen are removed by exhaust. The chemical formula showing this reaction is (1).
TiN + 2Cl ₂ → TiCl ₄ + (1/2) N ₂ (1)

  Subsequently, step S1 is performed. In step S1, for example, when the workpiece M1 is heated at 1000 ° C. in the reaction furnace 11, cobalt is chlorinated to produce cobalt chloride. Further, since the melting point of cobalt chloride is 724 ° C. and its boiling point is 1049 ° C. at one atmospheric pressure, the produced cobalt chloride is a liquid. This cobalt chloride is melted and dropped to the lower part of the furnace and removed.

  Moreover, when the to-be-processed object M1 is heated at 1000 degreeC by making the atmospheric pressure in the reaction furnace 11 into 1 atmospheric pressure, tungsten carbide will be chlorinated and tungsten chloride and carbon will be produced | generated. At one atmospheric pressure, the melting point of tungsten chloride is 275 ° C., and its boiling point is 346.7 ° C., so that the produced tungsten chloride is a gas. Moreover, since carbon has a melting point higher than the temperature in the reaction furnace 11 at one atmospheric pressure, carbon is generated as a solid.

As described above, in step S1, liquid cobalt chloride, gaseous tungsten chloride, and solid carbon are generated. Here, the generated solid carbon is porous carbon having a porous structure. This porous carbon can be used as activated carbon having a very large specific surface area. FIG. 2 shows chemical formulas (2) and (3) showing the reaction in this step S1.
WC + 3Cl ₂ → WCl ₆ + C (2)
Co + Cl ₂ → CoCl ₂ (3)

  The production of tungsten chloride obtained by the reaction of the chemical formula (2) is about 1 hour after the inside of the reaction furnace 11 is heated to 1000 ° C. when the particle diameter of tungsten carbide placed on the placing shelf 11a is 100 μm or less. Finish in 80 minutes. And after reaction of Chemical formula (2) and (3) is complete | finished, argon gas is supplied in the reaction furnace 11. FIG. By supplying the argon gas, the chlorine gas in the reaction furnace 11 is discharged from the gas discharge port 11e. Thereafter, the carbon remaining on the mounting shelf 11a is cooled to 400 ° C. And the mounting shelf 11a is pulled up from the reaction furnace 11, and the remaining carbon is taken out in air | atmosphere after that.

  Further, the tungsten chloride and the process gas G1 generated by the reaction of the chemical formula (2) are discharged, for example, from the gas discharge port 11e to the cooling trap 12, as shown in FIG.

  Here, step S2 (second step) for condensing tungsten chloride is performed. In step S2, tungsten chloride is separated from mixed gas G2 containing tungsten chloride and chlorine gas.

  Process S2 is performed by the cooling trap 12 and the storage tank 13 of the processing apparatus 10, for example. The cooling trap 12 includes a refrigerant 12a. The refrigerant 12 a circulates in the cooling trap 12. The storage tank 13 is connected to the cooling trap 12. The storage tank 13 stores the liquid cooled by the cooling trap 12. In addition, as an apparatus which performs process S2, it is not limited to the cooling trap 12 and the storage tank 13, As long as it is a cooling apparatus which can condense tungsten chloride, various apparatuses can be used. Below, the method to process mixed gas G2 using the cooling trap 12 and the storage tank 13 is demonstrated.

  In step S2, the mixed gas G2 discharged to the cooling trap 12 from the gas discharge port 11e is cooled to a temperature not lower than the boiling point of the process gas G1 and not higher than the boiling point of tungsten chloride. Here, the melting point of tungsten chloride is 275 ° C., and the boiling point thereof is 346.7 ° C. The boiling point of the process gas G1 is less than 275 ° C. Therefore, when the mixed gas G2 is cooled at, for example, 280 ° C., only tungsten chloride becomes a liquid in the cooling trap 12 and the process gas G1 remains a gas.

  The liquefied tungsten chloride is stored in the storage tank 13. Thereafter, the tungsten chloride is sent to the oxidation reaction apparatus 14 shown in FIG. 4 (reference numeral B1 in FIG. 3). As described above, in step S2, tungsten chloride is liquefied to be separated from the mixed gas G2. Further, the process gas G1 that has passed through the cooling trap 12 is exhausted to the outside of the processing apparatus 10 via the three-way valve 17, or is sent to the gas inlet 11c of the reaction furnace 11 again. Here, when the process gas G1 is sent again to the gas inlet 11c, the process gas G1 can be effectively used without waste.

  Next, step S3 of heating tungsten chloride is performed. In step S3, the tungsten chloride condensed in step S2 is heated at a temperature equal to or higher than the boiling point of tungsten chloride. Then, tungsten chloride is vaporized. Here, the temperature at which tungsten chloride is heated can be set to 350 ° C., for example, because the boiling point of tungsten chloride is 346.7 ° C.

Subsequently, step S4 (third step) is performed in which tungsten chloride is oxidized to produce tungsten oxide and chlorine gas. In step S4, the tungsten chloride and oxygen vaporized in step S3 are heated at 1100 ° C., for example. Then, tungsten oxide and chlorine gas are generated. Tungsten oxide is produced as a powder. FIG. 2 shows a chemical formula (4) indicating the reaction in this step S4.
WCl ₆ + (3/2) O ₂ → WO ₃ + 3Cl ₂ (4)

  Steps S3 and S4 are performed, for example, in the oxidation reaction apparatus 14 shown in FIG. The oxidation reaction device 14 is an electric furnace and includes a heater 14b. For example, 500 ml / min tungsten chloride and 550 ml / min oxygen are supplied to the oxidation reaction device 14.

  Next, step S5 for taking out tungsten oxide is performed. In step S5, tungsten oxide is separated from the mixed gas C1 composed of chlorine gas and residual oxygen from the tungsten oxide, chlorine gas, and residual oxygen generated in step S4.

  Step S5 is performed by, for example, the cyclone 15 shown in FIG. The cyclone 15 stirs the tungsten oxide, chlorine gas, and residual oxygen generated in the oxidation reaction device 14. By this stirring, tungsten oxide as powder falls, and gaseous chlorine gas and residual oxygen are discharged to the outside of the cyclone 15. The tungsten oxide dropped by the cyclone 15 is stored in, for example, a container below the cyclone 15. The tungsten oxide stored in the container is converted into tungsten carbide, for example, by being mixed with carbon powder and then baked. In addition, as an apparatus which performs process S5, it is not limited to the cyclone 15, For example, it can replace with the cyclone 15 and a filter can also be used.

  Next, step S6 for reacting residual oxygen with activated carbon is performed. In step S6, for example, as shown in FIG. 5, the mixed gas C1 separated in step S5 is processed by the processing device 16 having activated carbon. Specifically, when the temperature in the processing apparatus 16 is 600 ° C., for example, only the residual oxygen in the mixed gas C1 is adsorbed on the activated carbon by the activated carbon of the processing apparatus 16. Thus, the mixed gas C1 is converted into chlorine gas by removing residual oxygen. The above steps S5 and S6 correspond to a fourth step of separating the chlorine gas from the tungsten oxide and the mixed gas C1.

  In step S7, the chlorine gas in the processing apparatus 16 is exhausted from the processing apparatus 16, and then refluxed to the gas inlet 11c of the reaction furnace 11 as the process gas G1.

  In this manufacturing method, cobalt chloride and tungsten chloride are generated in step S1. In step S2, tungsten chloride is separated from the mixed gas containing tungsten chloride and chlorine gas. In steps S3 and S4, the separated tungsten chloride is oxidized to produce tungsten oxide and chlorine gas. In steps S5 and S6, chlorine gas is separated from tungsten oxide and chlorine gas, and the separated chlorine gas is used again in step S1. Therefore, when the separated chlorine gas is used again, the amount of released chlorine gas is reduced, so that the environmental load can be reduced. Thus, in this embodiment, the tungsten component can be extracted while suppressing the release of chlorine gas.

  In Step S1, chlorine gas and tungsten carbide containing cobalt are heated at a temperature lower than the boiling point of cobalt chloride. Accordingly, since cobalt chloride becomes liquid or solid, cobalt chloride is condensed or solidified. Therefore, the condensed or solidified cobalt chloride is easily removed.

  Further, the process gas G1 is a mixed gas of chlorine gas and inert gas, or chlorine gas. In step S1, tungsten carbide is heated at a temperature of 750 ° C. or higher and 1000 ° C. or lower. As described above, when tungsten carbide containing cobalt is heated at a temperature of 750 ° C. or higher and 1000 ° C. or lower in a mixed gas of chlorine gas and inert gas, or chlorine gas, the production of cobalt chloride is promoted.

  Below, the manufacturing method of tungsten of a 2nd embodiment is explained. In the tungsten manufacturing method of this embodiment, tungsten is manufactured after removing impurities from tungsten carbide containing impurities. Here, as in the first embodiment, a process of manufacturing tungsten from a tungsten tool will be described.

  6 and 7 are diagrams showing main steps of the tungsten manufacturing method according to the present embodiment. Steps S11 to S13 in FIG. 6 are the same as steps S1 to S3 of the first embodiment, and thus detailed description thereof is omitted.

In step S14 (third step), tungsten chloride is reduced to produce tungsten and chlorine gas. In step S14, the tungsten chloride and hydrogen vaporized in step S13 are heated at 1000 ° C., for example. Then, tungsten and hydrochloric acid gas are generated. Tungsten is produced as a powder. FIG. 7 shows a chemical formula (5) indicating the reaction in this step S14.
WCl ₆ + 3H ₂ → W + 6HCl (5)

  Step S14 is performed by, for example, the reduction reaction device 24 shown in FIG. The reduction reaction device 24 is an electric furnace and includes a heater 24b. For example, 500 m / min tungsten chloride and 550 m / min hydrogen gas are supplied to the reduction reaction device 24.

  Next, step S15 for taking out tungsten is performed. In step S15, tungsten is separated from the mixed gas C2 composed of hydrochloric acid gas and residual hydrogen from the tungsten, hydrochloric acid gas, and residual hydrogen generated in step S14.

Step S15 is performed by, for example, a cyclone 25 shown in FIG. Similarly to the cyclone 15, the cyclone 25 agitates tungsten, hydrochloric acid gas, and residual oxygen. Then, gaseous hydrochloric acid gas and residual hydrogen are discharged to the outside of the cyclone 25. Tungsten dropped by the cyclone 25 is stored in a container below the cyclone 25, for example. In addition, as an apparatus which performs process S15, it is not limited to the cyclone 25. FIG. Further, instead of steps S14 and S15, the reduction reaction device 24 may react tungsten chloride with methane gas. The chemical formula (6) showing this reaction is shown below.
WCl ₆ + (3/2) CH ₄ → WC + 6HCl + (1/2) C (6)

  In the reaction of the chemical formula (6), tungsten carbide and carbon are obtained as powder instead of obtaining tungsten in step S15. In the reaction of chemical formula (6), hydrochloric acid gas is obtained as in step S15.

  Next, step S16 (fifth step) in which hydrochloric acid gas is reacted with silicon is performed. In step S16, the hydrochloric acid gas, residual hydrogen, and metallic silicon obtained in step S15 are heated to generate silicon chloride.

  Step S16 is performed, for example, in the reaction furnace 11 of the processing apparatus 30 having the same configuration as the processing apparatus 10 shown in FIG. The metal silicon M3 is placed on the placement shelf 11a of the reaction furnace 11. A mixed gas C <b> 2 is supplied to the reaction furnace 11 from the gas inlet 11 c of the reaction furnace 11. In addition, the atmosphere containing hydrochloric acid gas around the metal silicon M3 is heated by the heater 11d of the reaction furnace 11 to be, for example, 900 ° C. to 1100 ° C.

When the metal silicon M3 and hydrochloric acid gas are heated at, for example, 900 ° C. to 1100 ° C. under one atmospheric pressure, the metal silicon M3 is chlorinated to generate silicon chloride and hydrogen. Further, at one atmospheric pressure, the melting point of silicon chloride is −70 ° C., and the boiling point thereof is 57.6 ° C. Therefore, the generated silicon chloride is a gas. Hydrogen is a gas because its boiling point is lower than the temperature in the reaction furnace 11. FIG. 7 shows a chemical formula (7) showing the reaction in this step S16.
Si + 4HCl → SiCl ₄ + 2H ₂ (7)

  Further, the silicon chloride and hydrogen gas generated by the reaction of the chemical formula (7) are discharged from the gas discharge port 11e to the cooling trap 12, for example, as shown in FIG.

  Here, step S17 for condensing silicon chloride is performed. In step S17, silicon chloride is separated from the mixed gas G4 containing silicon chloride and hydrogen gas.

  Step S17 is performed, for example, in the cooling trap 12 and the storage tank 13 of the processing apparatus 30. In step S17, the mixed gas G4 is cooled to a temperature not lower than the boiling point of hydrogen gas and not higher than the boiling point of silicon chloride. Here, at one atmospheric pressure, the melting point of silicon chloride is −70 ° C., and the boiling point thereof is 57.6 ° C. Further, at one atmospheric pressure, the boiling point of hydrogen gas is less than −70 ° C., which is the melting point of silicon chloride. Therefore, when the mixed gas G4 is cooled at, for example, −20 ° C., only the silicon chloride becomes liquid in the cooling trap 12 and the hydrogen gas remains as a gas. In addition, as an apparatus which performs process S17, it is not restricted to the cooling trap 12 and the storage tank 13, You may use another apparatus.

  The silicon chloride liquefied in step S17 is sent to the oxidation reaction apparatus 34 shown in FIG. 10 having the same configuration as that of the oxidation reaction apparatus 14 (reference numeral B3 in FIG. 9). In this way, in step S17, silicon chloride is liquefied, so that silicon chloride is separated from the mixed gas G4. Further, the hydrogen gas that has passed through the cooling trap 12 is exhausted to the outside of the processing apparatus 10 via the three-way valve 17, or is sent again to the gas inlet 11 c of the reaction furnace 11.

  Next, step S18 for heating silicon chloride is performed. In step S18, the silicon chloride condensed in step S17 is heated at a temperature equal to or higher than the boiling point of silicon chloride. And silicon chloride is vaporized. Here, since the boiling point of silicon chloride is 57.6 ° C., the temperature for heating silicon chloride can be set to, for example, 80 ° C.

Subsequently, step S19 (sixth step) in which silicon chloride is oxidized to generate silicon oxide and chlorine gas is performed. In step S19, the silicon chloride and oxygen vaporized in step S18 are heated at 110 ° C., for example. Then, silicon oxide and chlorine gas are generated. Silicon oxide is produced as a powder. FIG. 7 shows a chemical formula (8) showing the reaction in this step S19.
SiCl ₄ + O ₂ → SiO ₂ + 2Cl ₂ (8)

  Steps S18 and S19 are performed in an oxidation reaction apparatus 34 having the same configuration as that of the oxidation reaction apparatus 14 shown in FIG. For example, for example, silicon tetrachloride at 500 m / min and oxygen at 490 m / min are supplied to the oxidation reaction device 34.

  Next, step S20 for taking out silicon oxide is performed. In step S20, the mixed gas C1 composed of chlorine gas and residual oxygen and silicon oxide are separated from the silicon oxide, chlorine gas, and residual oxygen generated in step S19.

  Step S20 is performed by, for example, the cyclone 35 shown in FIG. 10 having the same configuration as the cyclone 15. The cyclone 35 agitates the silicon oxide, chlorine gas, and residual oxygen generated by the oxidation reaction device 34. The mixed gas C1 is discharged to the outside of the cyclone 35. For example, the silicon oxide is stored in a container below the cyclone 35. Note that step S20 may be performed by an apparatus other than the cyclone 35.

  Next, step S21 for reacting residual oxygen with activated carbon is performed. Since the process of process S21 is the same as process S6 of 1st Embodiment, the description is abbreviate | omitted. Further, the above steps S20 and S21 correspond to a seventh step of separating the chlorine gas from the silicon oxide and the mixed gas C1. In step S22, as in step S7 of the first embodiment, the chlorine gas in the processing apparatus 16 is returned to the gas inlet 11c of the reaction furnace 11 as the process gas G1.

  In this manufacturing method, cobalt chloride and tungsten chloride are generated in step S11. In step S12, tungsten chloride is separated from the mixed gas containing tungsten chloride and chlorine gas. In steps S13 and S14, the separated tungsten chloride is reduced to produce tungsten and hydrochloric acid gas. Then, after the hydrochloric acid gas is separated in step S15, the hydrochloric acid gas and silicon are heated in step S16 to generate silicon tetrachloride. After silicon tetrachloride and oxygen are heated in steps S17 to S19 to generate silicon oxide and chlorine gas, chlorine gas is separated from the silicon oxide and chlorine gas in steps S20 and S21. The separated chlorine gas is used again in step S11. Therefore, when the separated chlorine gas is used again, the amount of released chlorine gas is reduced, so that the environmental load can be reduced. Thus, in this embodiment, tungsten can be extracted while suppressing the release of chlorine gas.

  In step S11, as in the first embodiment, since cobalt chloride becomes a liquid or solid, it can be easily removed by condensing or solidifying cobalt chloride. Further, as in the first embodiment, the process gas G1 is a mixed gas of chlorine gas and inert gas, or chlorine gas, and tungsten carbide containing cobalt is heated at a temperature of 750 ° C. or more and 1000 ° C. or less. Production of cobalt chloride is promoted.

  DESCRIPTION OF SYMBOLS 10,30 ... Processing apparatus, G1 ... Process gas, M1 ... Tool, S1, S11 ... First step, S2, S12 ... Second step, S4, 14 ... Third step, S5, S6, S15 ... First 4 process, S16 ... 5th process, S19 ... 6th process, S20, S21 ... 7th process.

Claims (8)

A first step in which tungsten carbide containing impurities is exposed to a heated atmosphere of a process gas containing chlorine gas to produce chlorides of the impurities and tungsten chloride;
A second step of separating the tungsten chloride from the mixed gas containing tungsten chloride and chlorine gas;
After separating the tungsten chloride, oxidizing the tungsten chloride to produce tungsten oxide and chlorine gas;
A fourth step of separating the chlorine gas from the tungsten oxide and chlorine gas to obtain the tungsten oxide;
With
Using the chlorine gas separated in the fourth step in the first step ,
In the first step, the chlorine gas and the tungsten carbide are heated at a temperature lower than the boiling point of the chloride . The process gas is a mixed gas of chlorine gas and inert gas, or chlorine gas,
In the first step,
The said tungsten carbide is a manufacturing method of the tungsten oxide of Claim 1 heated at the temperature of 750 degreeC or more and 1000 degrees C or less. The method for producing tungsten oxide according to claim 1 or 2 , wherein in the first step, the chloride is a liquid. The said impurity is a manufacturing method of the tungsten oxide as described in any one of Claims 1-3 which is cobalt. A first step in which tungsten carbide containing impurities is exposed to a heated atmosphere of a process gas containing chlorine gas to produce chlorides of the impurities and tungsten chloride;
A second step of separating the tungsten chloride from the tungsten chloride and the chlorine gas;
After separating the tungsten chloride, a third step of reducing the tungsten chloride to produce tungsten and hydrochloric acid gas;
A fourth step of separating the hydrochloric acid gas from the tungsten and hydrochloric acid gas to obtain the tungsten;
After separating the hydrochloric acid gas, heating the hydrochloric acid gas and silicon to produce silicon chloride;
A sixth step of heating the silicon chloride and oxygen to produce silicon oxide and chlorine gas;
A seventh step of separating the chlorine gas from the silicon oxide and chlorine gas to obtain the silicon oxide;
With
Using the chlorine gas separated in the seventh step in the first step ,
In the first step, the chlorine gas and the tungsten carbide are heated at a temperature lower than the boiling point of the chloride . The process gas is a mixed gas of chlorine gas and inert gas, or chlorine gas,
In the first step,
The said tungsten carbide is a manufacturing method of tungsten of Claim 5 heated at the temperature of 750 degreeC or more and 1000 degrees C or less. The method for producing tungsten according to claim 5 or 6 , wherein, in the first step, the chloride is a liquid. The impurity is a cobalt, a manufacturing method of tungsten according to any one of claims 5-7.

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