JP2010077470A - Method for treating material to be treated, containing platinum group element, rhenium and/or arsenic - Google Patents

Abstract

When a platinum group element, rhenium, or arsenic is contained in a material to be treated, the platinum group element is transferred to the molten metal side for concentration, and the rhenium and arsenic are efficiently concentrated and separated. The purpose is to do.
A material to be treated containing a platinum group element, rhenium, and arsenic and a copper source material are charged together with a flux component and a reducing agent into an electric furnace and melted to be separated into a primary slag layer and a primary metal layer. Then, the primary metal is charged into an oxidation furnace and oxidized to separate into a secondary slag layer and a secondary metal layer, and dust is recovered from the gas introduced from the space in the oxidation furnace, After leaching with a solution and solid-liquid separation to obtain a solution in which rhenium and arsenic are leached, chloride is added to the solution for solid-liquid separation.
[Selection] Figure 1

Description

  The present invention relates to a material to be treated containing a platinum group element and rhenium and / or arsenic, for example, a used petrochemical catalyst, a used automobile exhaust gas purification catalyst, a used electronic substrate, a lead frame, etc. It is related with the method of concentrating and isolate | separating.

  Conventionally, as a method for recovering each contained element such as platinum group elements from used automobile exhaust gas purification catalyst (ceramic carrier catalyst and metal carrier catalyst of exhaust gas converter: these are called "automobile catalyst") Wet methods such as a solution in which an oxidizing agent is added to an acid such as water, a method of extracting a platinum group element or the like with an aqueous alkali solution or an aqueous ammonia solution, a method of dissolving a carrier using sulfuric acid or the like and separating it from an undissolved platinum group element or the like There is a processing method.

Further, JP-A-4-317423, JP-A-2000-248322, and JP-A-2005-5201 by the applicants disclose that a platinum group element-containing substance such as an automobile catalyst is contained in a copper source in an electric furnace. The platinum group element is transferred into the molten metal (molten copper metal) by melting with the material (copper oxide and / or metallic copper), and the molten metal containing the platinum group element thus obtained is further oxidized. Thus, there is a description of a dry processing method in which a molten oxide and a molten metal in which a platinum group element is further concentrated are separated into layers.
JP 2006-130387 A JP-A-6-17160 JP-A-4-317423 JP 2000-248322 A JP 200554201 A

However, for the treatment of the material to be treated containing platinum group elements and rhenium and / or arsenic, according to the wet treatment methods such as Patent Documents 1 and 2 (that is, the method of leaching using an acid or alkali), There are problems in terms of recovery rate and cost, such as poor extraction rate of platinum group elements and the like, and the use of a large amount of acid to dissolve the carrier, and it was not a practical method.
On the other hand, the dry processing method (that is, the melting processing method) for transferring the platinum group element into the molten metal such as Patent Documents 3 to 5 can recover the platinum group element at a high yield and at a low cost. It is a very excellent method that has advantages not found in wet processing methods as an efficient method for recovering valuable metals, but it contains rhenium and / or arsenic along with platinum group elements in the material to be treated. If so, the separation method of these rhenium and arsenic has not been solved.
In the present invention, when rhenium and / or arsenic is contained together with the platinum group element in the material to be treated, the platinum group element is moved to the molten metal side and concentrated, and these rhenium and arsenic are efficiently concentrated. The object is to provide a method of separation.

The present invention has been made to solve the above problems. First, a copper source material mainly comprising at least one selected from the group consisting of a material to be treated containing a platinum group element and rhenium, and metallic copper and copper oxide. Are charged into an electric furnace together with a flux component and a reducing agent, melted and separated into an oxide-based primary slag layer and a metallic copper-based primary metal layer, and then the primary metal is charged into an oxidation furnace. In the step of separating the oxide-based secondary slag layer and the metal copper-based secondary metal layer enriched with platinum group elements, by separating dust from the gas guided from the oxidation furnace space, A method of treating a material to be treated containing platinum group element and rhenium, which separates rhenium from the step of recovering the platinum group element, and second, a material to be treated containing platinum group element and arsenic, and a metal Group consisting of copper and copper oxide The copper source material mainly composed of at least one selected from the above is charged into an electric furnace together with a flux component and a reducing agent and melted and separated into an oxide-based primary slag layer and a metallic copper-based primary metal layer, In the step of charging the primary metal into an oxidation furnace and subjecting it to an oxidation treatment to separate it into a secondary slag layer mainly composed of oxide and a secondary metal layer mainly composed of metallic copper enriched in platinum group elements, A method for treating a material containing platinum group elements and arsenic, in which arsenic is separated from a step of recovering platinum group elements by separating dust from the introduced gas. Third, platinum group elements, A material to be treated containing rhenium and arsenic and a copper source material mainly composed of at least one selected from the group consisting of metallic copper and copper oxide are introduced into an electric furnace together with a flux component and a reducing agent, and melted into an oxide. The primary slur of the subject After separating the layer and the primary metal layer mainly composed of copper metal, the primary metal is charged into an oxidation furnace and oxidized to form a secondary slag layer mainly composed of oxide and a secondary layer composed mainly of metal copper enriched with platinum group elements. Contains platinum group elements, rhenium and arsenic, separating rhenium and arsenic from the process of recovering platinum group elements by separating dust from the gas introduced from the space inside the oxidation furnace in the step of separating into metal layers It is the processing method of the to-be-processed substance.
The term “rhenium” in the present invention means a rhenium element, which is a concept including a case of rhenium alone, a rhenium alloy, a rhenium compound, etc., and “arsenic” in the present invention means an arsenic element. The concept includes cases of arsenic alone, arsenic compounds, and the like.

In these present inventions, it is preferable that at least a part of the collected dust is repeatedly charged into at least one of the electric furnace and the oxidation furnace, thereby rhenium and / or arsenic in the dust. Can be further concentrated, and rhenium and / or arsenic can be concentrated to a higher concentration and separated.
Furthermore, in these present inventions, it is preferable that at least a part of the secondary slag is cooled with water in a molten state to obtain a granule containing copper oxide, and the granule is used as the copper source material. Preferably, at least a part of the secondary slag is reduced in a molten state to obtain a metallic copper-containing material, and the metallic copper-containing material is used as the copper source material. According to these aspects, at least a part of the copper raw material can be repeatedly used, the amount of waste slag can be reduced, and the cost can be reduced.
In addition, a solution in which rhenium and / or arsenic is concentrated is obtained by leaching the dust separated and recovered from the above-mentioned step of recovering the platinum group element from the material to be treated with an alkaline solution and solid-liquid separating the slurry. Since the leaching residue contains a platinum group element, the platinum group element in the leaching residue is recovered and recovered by repeatedly charging it into at least one of the electric furnace and the oxidation furnace. It is more preferable to improve the rate.

  According to the present invention, platinum is streamlined while the furnace operation is streamlined by a dry process of concentrating platinum group elements into molten metal copper from a material to be treated containing platinum group elements and rhenium and / or arsenic, such as catalysts for automobile exhaust gas purification The platinum group element can be efficiently recovered from waste resources by recovering the group element in high yield, and the rhenium and / or arsenic contained in the treated material together with the platinum group element can be efficiently concentrated. When both rhenium and arsenic are contained, they can be separated.

  In the present invention, the platinum group element and the material to be treated containing rhenium and / or arsenic include, for example, used petrochemical catalysts, used automobile exhaust gas purification catalysts, used electronic substrates, lead frames, etc. Also included are lot-out products and scraps obtained from these manufacturing processes. Such a material to be treated containing a platinum group element and rhenium and / or arsenic is usually in a state where a trace amount of the platinum group element and rhenium and / or arsenic are supported on a carrier such as a metal oxide or ceramic.

The material to be treated containing these platinum group elements and rhenium and / or arsenic (these elements may be collectively referred to as platinum group elements etc.) is at least one selected from the group consisting of metallic copper and copper oxide. The main copper source material, flux, and reducing agent such as carbonaceous material are charged into an electric furnace (preferably a closed electric furnace) and melted. The main molten primary metal layer is allowed to settle, and the platinum group elements and the like are concentrated in the molten primary metal layer that has settled downward. At that time, from the melting of the charge to the discharge of the melt, It is preferable to use a granular material having a particle size of 0.1 mm or more and 10 mm or less as the copper source material charged in the electric furnace while maintaining the pressure at a pressure lower than atmospheric pressure.
Hereinafter, these matters specified by the present invention will be described.

  FIG. 1 shows an example of an electric furnace used in the method of the present invention. In FIG. 1, reference numeral 1 denotes a closed electric furnace. The closed electric furnace 1 includes a furnace body 3 having a furnace space 2 that is substantially blocked from outside air, a charge input port 4 and an exhaust port 5 provided in an upper body portion of the furnace body 3, At least two fluid discharge ports 6 and 7 having different height levels provided in the lower half of the furnace body 3, a charge input chute 8 connected to the charge input port 4, and the exhaust port And an electrode 10a, 10b, 10c for energizing and heating the charge charged in the furnace.

  The furnace body 3 shown in the figure is a furnace having a circular inner wall lined with a refractory, and a delivery input chute 8 is arranged almost at the center of the ceiling surface. Three electrodes 10a, 10b, and 10c are arranged on the concentric circles vertically from the ceiling surface at equal intervals. In other words, the positions of the vertical electrodes 10a, 10b, and 10c are at the vertices of the equilateral triangle, and the charge throwing chute 8 exists at the approximate center of the equilateral triangle.

  The sealed electric furnace 1 configured in this manner includes a granular material 11 containing a platinum group element and rhenium and / or arsenic, and a copper source mainly composed of at least one selected from the group consisting of metallic copper and copper oxide. The material 12, the solid reducing material (for example, powdery coke) 13 and the powdery flux 14 are mixed and charged. That is, these charging raw materials are weighed and cut out from the respective hoppers, and are fed into the charging charge chute 8 of the electric furnace 1 while being mixed and conveyed by the screw conveyor 15. The charging material charging chute 8 is provided with two upper and lower shutters 16 and 17 so that airtightness is maintained when the material is charged into the furnace. First, the upper shutter 16 is opened, the lower shutter 17 is closed, and one batch of charge is put into the chute 8, then the upper shutter 16 is closed, the lower shutter 17 is opened and stored in the chute 8. The batch that is being processed is put into the furnace. When the batch is charged into the furnace, the upper and lower shutters 16 and 17 are closed to prepare for the next charging operation. In the facility shown in the figure, the branch member 18 is attached to the lower end of the chute 8 (below the charge inlet 4), so that the charge falling into the furnace from the chute 8 is three electrodes 10a, 10b, 10c. Are landed in the vicinity of each side of the triangle connecting the two, more preferably near the midpoint position of each of the three sides. As a result, a new charge is deposited at the shortest distance connecting the electrodes 10a, 10b, and 10c, thereby increasing the melting efficiency.

  At the initial stage of operation of the furnace in which a new charge is charged, at least two fluid discharge ports 6 and 7 having different height levels provided in the lower body portion of the furnace body 3 are closed. The substance charged in the furnace starts to melt by energizing each electrode 10a, 10b, 10c, but during that time, the exhaust gas generated in the furnace by driving the exhaust device 9 passes from the exhaust port 5 to the dust removing device 19 Guided and exhausted after the exhaust gas treatment. By the continuous operation of the exhaust device 9, the furnace space 2 that is substantially blocked from the outside air is maintained at a pressure lower than the atmospheric pressure.

  The dust removing device 19 may be either a dry system that does not use a cleaning liquid or a wet system that cleans exhaust gas using a cleaning liquid. In the case of the dry method, lightning type flues (Zig-Zag Blue), dust collection chambers (Dust Chamber), cyclones, bag houses, cotrels, etc. can be arbitrarily selected. Further, the dust collected by the dust removing device 19 can be sintered or made as needed and repeatedly charged into the closed electric furnace 1 together with the charged raw materials.

  When the charge begins to melt in the furnace, the copper to be treated and the copper material in the copper source material are melted, and the copper oxide is reduced to metal copper by a reducing material (for example, powdered coke). Form copper. Since the metal melt has a higher specific gravity than the oxide melt (slag), the metal melt descends in the slag and settles below the furnace to form a molten metal pool 20. An oxide melt, that is, a primary slag layer 21 is formed on the molten metal 20.

  In the process in which the molten metal copper produced by reduction of metallic copper and copper oxide descends in the slag, platinum group elements and the like existing in the slag are taken into the molten metal copper. That is, let it melt. As a result, the molten metal 20 is collected in a state in which the platinum group elements and the like are dissolved in the molten metal 20, and the molten metal 20 having a high concentration of the platinum group elements and the like is obtained. On the other hand, the concentration of the platinum group element or the like in the slag 21 is lowered by the amount of the platinum group element or the like dissolved in the molten metal 20. Accordingly, the primary slag 21 having a lower concentration of platinum group elements and the like is separated from the higher fluid discharge port 6, and the primary metal melt 20 having a higher platinum group element concentration and the like is separated from the lower fluid discharge port 7. On the other hand, when it is made to flow out of the furnace, a molten metal having a high platinum group element concentration or the like (a metal in which a platinum group element or the like is dissolved in copper metal) can be collected.

  Since this closed electric furnace 1 is in a reducing atmosphere, most of the rhenium and / or arsenic charged together with the platinum group element is transferred to the molten metal 20 together with the platinum group element. That is, any element of platinum group elements, rhenium, and arsenic charged in the closed electric furnace 1 in a reducing atmosphere is concentrated in the molten metal 20.

  In the method of the present invention, it is preferable to use a granular material having a particle size of 0.1 mm or more and 10 mm or less as a copper source material charged in the electric furnace. When a granular material having a particle size of 0.1 mm or more and 10 mm or less is used as the copper source material, the platinum group element or the like in the substance to be treated moves into the molten metal at the stage where the substance to be treated and the copper source material are heated and melted. I found it easier. In particular, it is desirable that the copper source material has a particle size of 0.1 mm or more and 10 mm or less in an amount of 50% by weight or more. If the condition is satisfied, other materials may be a lump of 10 mm or more. In some cases, a powder of less than 0.1 mm may be mixed.

  Also for the substance to be treated containing a platinum group element or the like, at least 50% by weight or more is preferably a granular material having a particle diameter of 10 mm or less in order to improve the mixing property with the copper source material. Both the material to be treated and the copper source material are granular bodies with appropriate particle sizes, and when this is mixed with the carbonaceous reductant and flux, it is introduced into the furnace and the copper metal in the copper source material melts. In addition, the copper oxide is easily melted and reduced, and the generated molten metal copper has a greater chance of coming into contact with the platinum group element in the material to be treated. A lot of molten metal copper is taken in.

In order to promote the meltdown of the material to be treated and the copper source material and to improve the fluidity of the slag produced, it is desirable to add the flux simultaneously to the charge. As the flux, a mixture of silica, calcium oxide, calcium carbonate and the like in an appropriate ratio is preferable. The mixing ratio of the flux components varies depending on the composition of the raw material, but as the composition of the slag after heating and melting, Al ₂ O ₃ : 20 to 40% by mass, SiO ₂ : 25 to 35% by mass, CaO: 20 to 30% by mass, FeO : It is preferable to mix | blend a flux component with a charging raw material so that it may become 1-30 mass%.

  Coke is preferably blended as the reducing agent, but other than the coke, a base metal containing a valuable metal having a reducing action, a resin material as a carbon source, activated carbon, SiC, or the like can also be used. According to the present invention, valuable metals (noble metals and platinum group elements) contained in these reducing agents can also be recovered simultaneously.

  In carrying out the present invention, a sealed electric furnace was charged with a mixture of a substance to be treated, a copper source material, a flux and a reducing agent, and the furnace internal pressure was maintained at a pressure slightly lower than the atmospheric pressure at 1100 ° C. It is heated and melted at a temperature of ˜1700 ° C., more preferably 1300 ° C. to 1500 ° C., the oxide in the charging material is melted, and the copper oxide in the charging material is reduced to copper. If the heating and melting temperature is less than 1100 ° C, the molten state of the slag is not perfect and the viscosity is increased, and the recovery rate of platinum group elements and the like may be reduced. This will cause damage. By maintaining the inside of the furnace under reduced pressure, a reducing atmosphere is maintained, the reduction of copper oxide to copper proceeds well, and the absorption efficiency of the platinum group elements and the like into the molten metal is also increased.

  When the charge is melted down, most of the material to be treated becomes a glassy molten oxide layer (slag layer). Metallic copper melts, and copper oxide is reduced by a reducing agent to become molten metal copper. The slag layer and the metal layer are naturally separated into two layers due to the difference in specific gravity, and a primary slag layer is formed in the upper layer and a primary metal layer is formed in the lower layer. At this time, the platinum group element, rhenium, and arsenic in the material to be treated all move to the lower molten primary metal layer and are absorbed, but as described above, the grain size of the copper source material reduces its settling time and It greatly affects the improvement of the yield of platinum group elements and the like absorbed by the molten metal layer, and when the particle size of the copper source material is set to 0.1 mm or more and 10 mm or less, a remarkable effect appears on these improvements.

  The reason is not necessarily clear, but can be considered as follows. The platinum group element or the like in the material to be treated is dispersed in slag having an appropriate viscosity when the material to be treated is melted down together with the flux. In addition, immediately after the metal copper and copper oxide added simultaneously are reduced, the molten metal is dispersed in the slag as a molten metal, while absorbing the platinum group elements dispersed and suspended in the slag having an appropriate viscosity, Go down in the slag layer. The inventors named the behavior of the molten metal (copper metal) absorbing platinum group elements and the like as the “copper showering effect”. When the particle diameter of the initially supplied copper source material is less than 0.1 mm, the molten metal copper dispersed in the slag is also fine, so that it often settles down to the lower metal layer. It takes time and the copper showering effect does not work sufficiently. On the other hand, if the diameter of the initially introduced copper source material exceeds 10 mm, the molten metal copper forms a lower metal layer before sufficiently absorbing platinum group elements and the like dispersed in the slag. In this case, the copper showering effect does not function sufficiently. Further, in order for the descending molten metal copper to absorb the platinum group elements and the like dispersed in the slag, a certain surface area and cross-sectional area are required. That is, even if the weight of the input copper source material is the same, the larger the surface area and cross-sectional area, the higher the absorption efficiency. For these reasons, the copper showering effect works most efficiently when the particle size of the initially introduced copper source material is 0.1 mm or more and 10 mm or less. It is considered that the migration of platinum group elements and the like into the metal is favorably performed.

  According to the experience of the present inventors, there is substantially no problem in the recovery of platinum group elements and the like if the copper source material has a particle size in this range of 50% by mass or more, preferably 80% by mass or more. When the particle size is less than 50% by mass, it is necessary to take a long time for standing, that is, settling time, in order to increase the recovery rate of platinum group elements and the like. Here, stationary, that is, set ring, means that the slag that has already melted after the material is put into the electric furnace is energized as it is to maintain the temperature at a predetermined temperature. In the meantime, the pressure in the closed electric furnace is preferably maintained under reduced pressure.

  After this standing, the upper molten primary slag is discharged out of the furnace. At this time, it is preferable that most of the molten primary slag in the upper layer is left outside the furnace while part of the molten primary slag is left in the furnace because stress on the refractory inside the furnace due to temperature change in the furnace can be reduced. The molten primary metal layer that has absorbed platinum group elements and the like existing in the lower layer in the furnace is also tapped outside the furnace. In this case as well, when the molten primary metal layer that absorbs platinum group elements existing in the lower layer in the furnace is tapped outside the furnace while leaving a part of it in the furnace, the refractory in the furnace due to the temperature change in the furnace It is preferable because it can reduce stress on the surface. In the above preferred state, molten slag and other parts of the molten metal remain in the furnace, but in this state, the charging material of the next heat is charged into the furnace to reduce the stress on the refractory in the furnace. The same operation can be repeated again.

  The molten primary metal, which is concentrated from the sealed electric furnace and separated from the molten primary slag, is concentrated in the molten primary metal (preferably in a molten state) and charged in an oxidation furnace. Is concentrated in the molten metal.

  In the oxidation furnace, this molten metal is oxidized in the molten state, and the molten oxide (copper oxide) generated on the molten metal surface is discharged outside the furnace, leaving a molten metal in which the platinum group elements are further concentrated. That is, since the platinum group element hardly transfers to the molten oxide layer (secondary slag) formed on the molten metal surface and remains in the lower molten secondary metal layer, every time the generated molten oxide layer is discharged. In addition, the platinum group element concentration in the molten metal layer increases. The oxidation treatment in this oxidation furnace is preferably performed by introducing oxygen gas or oxygen-containing gas while maintaining the material temperature at a temperature of 1100 ° C. to 1700 ° C., preferably 1200 ° C. to 1500 ° C. If it is less than 1100 ° C., solidification of the molten oxide or molten metal occurs, and the progress of oxidation is inhibited. If the temperature exceeds 1700 ° C., the furnace body will be damaged.

  In this way, in the oxidation furnace, by repeating the oxidation treatment and the discharge treatment of the oxide layer, the molten secondary metal layer in which the platinum group element is concentrated has a platinum group element content of 10 to 75 mass%. Can be increased. After this is taken out from the oxidation furnace, it is sent to the platinum group element recovery and purification in the next step to separate and refine metallic copper and the platinum group element.

  On the other hand, the molten oxide layer (oxide mainly composed of copper oxide) discharged from the oxidation furnace can be reused as a copper source material charged in the electric furnace. At that time, by putting the oxide layer discharged from the oxidation furnace in a molten state into water, that is, by granulating, the granular material having a particle size of 0.1 mm or more and 10 mm or less is preferably 50% by mass or more. It can be set as the copper source material containing 80 mass% or more. The obtained granulated product can be further sized by a sieve or the like after drying to obtain a copper source material having a particle size suitable for the treatment of the present invention. Moreover, the oxide layer discharged | emitted in the molten state from this oxidation furnace can be reduce | restored, and it can also be made into copper source material as metallic copper. The molten oxide layer (oxide mainly composed of copper oxide) discharged from the oxidation furnace is inevitably accompanied by a small amount of platinum group elements. Since the group element eventually moves into the molten metal layer, the recovery rate of the platinum group element is further increased.

  In addition, in this oxidation furnace, an oxygen atmosphere or an oxygen-containing gas is introduced, so that most of the rhenium and / or arsenic in the molten metal charged with the platinum group element into the oxidation furnace becomes dust, and the inside of the oxidation furnace The exhaust gas containing the dust generated in step 1 is led from the oxidation furnace space to the dust recovery device via the exhaust port, and the dust is recovered. That is, both the elements of rhenium and arsenic in the molten metal charged in the oxidation furnace in an oxidizing atmosphere are separated from the secondary metal solution as dust.

  This dust recovery device from the oxidation furnace exhaust gas collects dust from the oxidation furnace exhaust gas without using a cleaning solution because the oxidation furnace charge is a primary solution metal, so that the exhaust gas contains almost no moisture. Even a dry dust recovery apparatus can be employed in any apparatus of a wet dust recovery apparatus that cleans oxidation furnace exhaust gas using a cleaning liquid and recovers dust in the exhaust gas into the cleaning liquid. Here, since most of the moisture is not contained in the oxidation furnace exhaust gas, in the case of using a lightning type flue (Zig-Zag Blue), a dust collection chamber (Dust Chamber), a cyclone, etc. in the dry method. There is no inconvenience that moist dust adheres to the exhaust gas passage and the passage becomes narrow and the exhaust fan is overloaded or dust collection becomes unstable, and the bag filter becomes damp when the baghouse is used. There is no inconvenience that the exhaust fan is overloaded or dust collection becomes unstable due to clogging with dust, and when cotrel is adopted, fluctuations in moisture in the exhaust gas or dust on the dust collection electrode There is an advantage that the electric field becomes unstable due to the adhesion of dust and the inconvenience that the dust collection becomes unstable, and the dust collected by the dry method is not generated. The strike can be temporarily stored in a dust storage unit such as below in the recovery device.

Subsequently, the leaching process of the dust collected by the dust collecting device of the oxidation furnace is performed. When dust is collected by a dry method, the dust is extracted from the dust collecting part or the dust storage part and leached with an alkaline solution. By this leaching treatment, when rhenium is contained in the dust, the rhenium is contained, when the dust contains arsenic, the arsenic is contained. When the dust contains rhenium and arsenic, the rhenium and arsenic are produced. They are leached together.
Here, sodium hydroxide, potassium hydroxide, ammonium hydroxide, or the like can be used as the alkaline solution.

  In addition, when a wet dust recovery device for cleaning the oxidation furnace exhaust gas using an alkaline solution as a cleaning liquid and recovering dust in the exhaust gas into the cleaning liquid is adopted as the dust recovery device from the oxidation furnace exhaust gas, dust recovery and alkali Solution leaching can be performed simultaneously.

  In the leaching process, the entire amount of collected dust may be processed. In addition, if a part of the collected dust is charged into at least one of the electric furnace and the oxidation furnace and repeated in the system, and the remainder is leached, the rhenium and arsenic in the dust are concentrated. As a result, rhenium and arsenic can be leached to a high concentration.

  Next, the slurry after the dust leaching treatment is subjected to solid-liquid separation to be separated into a solution in which rhenium and arsenic are dissolved and a leaching residue. Since the leaching residue contains a small amount of rhenium, arsenic, copper scattered from the oxidation furnace, and a platinum group element, it is charged into at least one of the electric furnace and the oxidation furnace and repeated in the system.

When the initial material to be treated contains platinum group elements and arsenic, the arsenic solution obtained by solid-liquid separation of the leached slurry can be dearsenated in a known wastewater treatment process.
In addition, when the material to be treated initially contains a platinum group element and rhenium, rhenium is precipitated by adding chloride to the rhenium solution obtained by solid-liquid separation of the leached slurry. Can be recovered.
Furthermore, if the initial material to be treated contains platinum group elements, rhenium and arsenic, chloride should be added to the solution of rhenium and arsenic obtained by solid-liquid separation of the leached slurry. The rhenium can be separated and recovered as a rhenium chloride precipitate by the arsenic solution, while the arsenic solution can be dearsenated in a known wastewater treatment process.
Sodium chloride, potassium chloride, ammonium chloride, etc. can be used as the chloride for addition.

[Example 1]
700 kg of copper source material (metallic copper) is mixed with 1500 kg of the substance to be treated containing 900 ppm of Pt, 40 ppm of Re, and 100 ppm of arsenic as an impurity, and further 1000 kg of CaO and 200 kg of Fe ₂ O ₃ as flux components. And 800 kg of SiO ₂ and 60 kg of coke as a reducing agent were mixed.
This mixture is put into an electric furnace, heated to 1350 ° C. and held in a molten state for 4 hours, and then the primary slag, which is a glassy oxide formed in the upper layer, flows out from the side of the electric furnace, and then the lower layer copper metal The primary metal (500 kg) was extracted from the lower part of the electric furnace and led to a heated oxidation furnace. Analysis of this metallic copper revealed Pt: 1890 ppm, Re: 82 ppm, and As205 ppm. In the oxidation furnace, oxygen-enriched air with 40% oxygen is blown to the above-mentioned metal copper (primary metal) at a position about 50 mm below the surface of the hot water melted with a lance to oxidize part of the metal copper, 450 kg was obtained. During this time, dust was collected from the upper part of the oxidation furnace, and 1.05 kg of oxidation furnace dust was collected on the bag filter.
When this dust was analyzed, they were Pt: 520 ppm, Re: 26000 ppm, As: 65000 ppm.
The dust was then leached into 4 liters of a 25% NaOH solution (denoted L). The leaching rate of Re was 96.4%, the leaching rate of As was 75.6%, and Pt was not leached and remained in the residue. It was.
The leaching residue was washed with water, dried at 100 ° C., and measured for mass. As a result, it was 0.6 kg, Pt: 910 ppm, Re: 1630 ppm, As: 27800 ppm. The leaching residue was put into an electric furnace together with other materials to be treated in order to recover Pt.
On the other hand, 4 L of the solution after leaching with NaOH contained Re: 6.6 g / L and As: 12.9 g / L, and 600 g of potassium chloride was added with stirring at room temperature of 20 ° C. to obtain a precipitate. When this precipitate was washed with water and dried at 100 ° C., a Re concentrate having a mass of 0.12 kg, Re: 20.5% by mass, and As: 2.2% by mass was obtained. The Re concentrate was targeted for Re recovery, and the filtrate was sent to the As wastewater treatment process.

It is a schematic sectional drawing which shows the example of the electric furnace used by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealed type electric furnace 2 Furnace space 3 Furnace body 4 Charge input 5 Exhaust 6 Higher fluid (primary slag) discharge 7 Lower fluid (primary metal) discharge 8 Charge input chute 9 Exhaust device 10 Electrode

Claims (6)

  A material to be treated containing a platinum group element and rhenium, and a copper source material mainly composed of at least one selected from the group consisting of metallic copper and copper oxide are charged together with a flux component and a reducing agent into an electric furnace and melted. After separation into a primary slag layer mainly composed of oxide and a primary metal layer mainly composed of copper metal, the primary metal is charged into an oxidation furnace and oxidized to concentrate the secondary slag layer mainly composed of oxide and platinum group elements. Separating the rhenium from the step of recovering the platinum group element by separating the dust from the gas introduced from the space inside the oxidation furnace, A method for treating a material containing rhenium.   A material to be treated containing a platinum group element and arsenic and a copper source material mainly composed of at least one selected from the group consisting of metallic copper and copper oxide are charged together with a flux component and a reducing agent into an electric furnace and melted. After separation into a primary slag layer mainly composed of oxide and a primary metal layer mainly composed of copper metal, the primary metal is charged into an oxidation furnace and oxidized to concentrate the secondary slag layer mainly composed of oxide and platinum group elements. Separating the arsenic from the step of recovering the platinum group element by separating the dust from the gas introduced from the space inside the oxidation furnace, A method for treating substances to be treated containing arsenic.   A material to be treated containing a platinum group element, rhenium and arsenic, and a copper source material mainly composed of at least one selected from the group consisting of metallic copper and copper oxide are charged into an electric furnace together with a flux component and a reducing agent. After being melted and separated into a primary slag layer mainly composed of oxide and a primary metal layer mainly composed of metal copper, the primary metal is charged into an oxidation furnace and oxidized to form a secondary slag layer mainly composed of oxide and a platinum group element. In the step of separating the layer into a concentrated metallic copper-based secondary metal layer, platinum is separated from the step of recovering the platinum group element by separating the dust from the gas introduced from the space in the oxidation furnace. For the treatment of substances containing group elements, rhenium and arsenic.   The processing method according to any one of claims 1 to 3, wherein at least a part of the collected dust is charged into at least one of the electric furnace and the oxidation furnace.   5. The granule containing copper oxide is obtained by water-cooling at least a part of the secondary slag in a molten state, and the granule is used as the copper source material. Processing method.   The processing method according to any one of claims 1 to 5, wherein a solution in which rhenium and / or arsenic is concentrated is obtained by leaching the recovered dust with an alkaline solution and solid-liquid separation.

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