TWI648407B - Process for separating precious metal from particulate precious metal-containing refractory material - Google Patents

Abstract

Provided herein is a method of separating a precious metal from a particulate noble metal-containing refractory comprising the steps of: (1) providing a particulate noble metal-containing refractory; (2) providing the temperature in the step (1) at 200 ° C to 650 The granular noble metal-containing refractory material and the chlorine and gaseous aluminum chloride and inert gas (if applicable) provided in the fluidized bed by means of the upward gas flow in the hot fluidized bed at a temperature of 200 ° C to 650 ° C Contact; and (3) directing the gas stream exiting the fluidized bed in an upward direction.

Description

Method for separating precious metals from granular noble metal-containing refractories

The present invention relates to a method for separating precious metals from granular noble metal-containing refractories.

US 2,860,045 discloses the separation of platinum from a platinum-containing alumina support material by contact with a combination of gaseous aluminum chloride and, if applicable, a dilute carrier gas (e.g., helium, nitrogen, chlorine, carbon dioxide, air, carbon monoxide, etc.).

Based on the prior art of US 2,860,045, the Applicant seeks to further develop the object disclosed therein with respect to the principle of separating precious metals from particulate noble metal-containing refractories particularly effectively. In particular, the precious metal is to be rapidly and substantially completely separated from the bulk refractory material without the need to utilize a complex or multi-stage chemical reaction system. For example, it is feasible to substantially completely separate the precious metal from 5 kg to 3,000 kg of the particulate noble metal-containing refractory material in a period of less than 5 hours by means of the method to be designed. Substantially complete separation of the precious metal is understood to mean reducing the precious metal content of the particulate precious metal-containing refractory material from a typical starting value of from about 0.01% by weight to about 5% by weight or from 0.1% by weight to 5% by weight to the weight. A residual content of, for example, 10 ppm to 900 ppm, especially a residual content of, for example, 10 ppm to 200 ppm by weight, cannot be further reduced for economic reasons.

This object can be achieved by the process of the invention for separating precious metals from granular noble metal-containing refractories as disclosed hereinafter. The method comprises the steps of: (1) providing a granular noble metal-containing refractory material; (2) providing the temperature in the step (1) and providing the temperature in the range of 200 ° C to 650 ° C, preferably 250 ° C to 600 ° C, especially 300 ° C to Granular precious metal-containing refractories in the range of 500 ° C and supplied by means of an upward gas flow as a fluidized bed (German: Wirbelbett, Fließbett; fluidization by means of upward gas flow) with chlorine and gaseous aluminium chloride and inert gas (if applicable) at 200 ° C Contacting in a hot fluidized bed at a temperature of 650 ° C, preferably 250 ° C to 600 ° C, especially 300 ° C to 500 ° C; and (3) conducting a gas stream that exits from the fluidized bed in an upward direction.

In a preferred embodiment of the process of the invention, it is achieved during the step (2) that the particulate noble metal-containing refractory material is contacted with chlorine and gaseous aluminum chloride and/or treated with chlorine and gaseous aluminum chloride, wherein the upward gas flow comprises A stream of gaseous aluminum chloride, chlorine and an inert gas (if applicable) or a gas mixture consisting essentially of it. The process of the invention then comprises the steps of: (1) providing a granulated precious metal-containing refractory material; (2) providing the temperature in the step (1) and at a temperature of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C, especially 300 Between ° C and 500 ° C, and by means of an upward gas flow, a granular noble metal-containing refractory material provided as a fluidized bed and gaseous aluminum chloride, chlorine and an inert gas as a component or a substantially core component of the upward gas mixture (if applicable) a contact in a heated fluidized bed at a temperature of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C, especially from 300 ° C to 500 ° C; and (3) a gas stream that is directed away from the fluidized bed in an upward direction.

In other words, in a preferred embodiment of the process of the invention, the gas mixture comprises or consists essentially of gaseous aluminum chloride, chlorine and an inert gas, if applicable.

The term "granular precious metal-containing refractory" is used herein. The term refers to a particulate refractory material whose surface and/or pore surface is provided with a precious metal and/or in the form of a mixture comprising precious metal particles. In other words, the particulate refractory material in the granular noble metal-containing refractory material is used as a precious metal support material and/or as a component of the mixture.

The term "precious metal" and / or "containing precious metals" is used herein. Unless otherwise stated, the terms mean a single precious metal or a combination of different precious metals, each selected from the group consisting of silver, gold, ruthenium, rhodium, iridium, osmium, platinum, palladium and rhodium, especially selected Free group of the following components: platinum, palladium and rhodium.

The term "granular refractory" is used herein. Granular refractories and/or granules (refractory granules) produced from refractory materials are understood to be granules made from inorganic non-metallic materials which are at elevated temperatures (for example, in the range of 200 ° C to 650 ° C). Internally, it acts against chlorine and aluminum chloride, ie it does not change or substantially does not change in this case physically and chemically. For example, this can be a ceramic refractory material. Suitable refractory materials may be selected, for example, from the group consisting of alumina (eg, alpha-alumina or gamma-alumina), titanium dioxide, ceria, magnesia, zirconia, mixed oxides (eg, , cerium/zirconium mixed oxides, cerium salts (eg, aluminum citrate (eg, cordierite, mullite, zeolite)), titanates (eg, aluminum titanate, lead zirconate titanate, and titanic acid)钡), tantalum carbide and tantalum nitride. The refractory material can be doped, for example, by a non-noble metal. Therefore the refractory material does not contain precious metals. The refractory material may be present singly or in combination, for example in a mixture of different particulate refractory materials and/or in an intragranular combination. In general, the particles made from the refractory material are porous.

The term "no precious metal" as used herein is understood to mean that no precious metal is present, but the precious metal content and/or residual precious metal content is, for example, >0 ppm to 10 by weight. Within the ppm range, it is essentially unavoidable for the corresponding material for technical reasons.

In the step (1) of the method of the present invention, for example, in the form of a mixture of one or more types of precious metal-containing refractory particles, or in the form of a mixture of noble metal-free refractory particles and precious metal-containing refractory particles, or A granular precious metal-containing refractory material is provided in the form of a mixture of precious metal particles and no precious metal and/or precious metal-containing refractory particles. Mixtures of precious metal-free refractory particles with precious metal-containing refractory particles, or mixtures of precious metal particles with non-precious metals and/or precious metal-containing refractory particles may be intentionally produced; however, this is generally not the case and may have been produced for technical reasons. A mixture of this type.

The particles produced from the noble metal-containing refractory material may have an absolute particle diameter in the range of, for example, 3 μm to 500 μm. Examples of such granules include disintegrated (waste) heterogeneous catalysts, disintegrated slag, precious metal slag, dried and disintegrated sludge, disintegrated waste electrical and electronic equipment, disintegrated mining concentrates and Disintegrated mining waste.

The precious metal content in the granular noble metal-containing refractory material provided in the step (1) is each in the range of, for example, 0.01% by weight to 10% by weight or 0.01% by weight to 5% by weight based on the total particulate precious metal-containing refractory material. Within, or preferably in the range of from 0.1% by weight to 5% by weight.

The granulated precious metal-containing refractory material may be selected from a group consisting of a material or a combination of different materials: disintegrated slag, precious metal slag, dried and disintegrated sludge, disintegrated waste electricity and electronics Equipment, disintegrating mining concentrates, disintegrating mining waste and precious metal-containing heterogeneous catalysts.

In one embodiment, the particulate noble metal-containing refractory material can be a disintegrated, for example ground, slag. Examples include precious metal-containing slags from pyrometallurgical precious metal refining processes.

In another embodiment, the granular precious metal-containing refractory material may be a precious metal slag, such as precious metal slag from the jewelry or dental industry. The precious metal slag can be pretreated. For example, its It can be subjected to ashing and/or extraction and/or disintegration with nitric acid, for example by grinding. Ashing allows removal of organic components, for example by means of pyrolysis and/or combustion. Nitric acid extraction allows the removal of nitric acid soluble substances, especially nitric acid soluble metals such as copper and silver.

In another embodiment, the particulate noble metal-containing refractory material can be, for example, dried and disintegrated, such as ground, sludge from a hydrometallurgical precious metal refining process. In addition, the sludge can be annealed.

In another embodiment, the particulate noble metal-containing refractory material can be disintegrated, such as ground waste electrical and electronic equipment. In addition, waste electrical and electronic equipment can be ashed or annealed. Annealing or ashing allows removal of organic components, for example by means of pyrolysis and/or combustion.

In another embodiment, the particulate precious metal-containing refractory material can be a disintegrated, for example ground, mining concentrate. Examples of mining concentrates include materials derived from precious metal ores, containing natural precious metals and having an increased concentration of precious metal portions. Examples of concentration methods are those well known to those skilled in the art, such as flotation, pyrometallurgical melting processes, and hydrometallurgical processes.

In another embodiment, the particulate noble metal-containing refractory material can be disintegrated, such as ground mining waste. Examples include natural precious metal-containing mining waste from precious metal ore.

Specifically, the granular noble metal-containing refractory material contains a noble metal heterogeneous catalyst, especially a noble metal heterogeneous catalyst. The noble metal-containing heterogeneous catalyst can be derived from a wide range of sources. For example, waste precious metal heterogeneous catalysts can be, for example, waste exhaust air purification catalysts from the chemical, pharmaceutical, and petrochemical industries; waste exhaust gas purification catalysts; waste combustion exhaust gas purification catalysts; waste diesel particulate filtration a waste catalyst for the production of pure gases; and/or a waste process catalyst. Examples of process catalysts include Fischer-Tropsch catalysts, reforming catalysts, catalysts for the production of ethylene oxide, and hydrogenation catalysts.

Heterogeneous catalysts may, for example, be present in the following forms: (i) coated with a precious metal but not coated with a carrier The form of the refractory support material of the cloth, (ii) in the form of a refractory support material provided with a noble metal coating of the carrier coating but not containing the precious metal itself, or (iii) a precious metal-containing coating provided with a carrier coating and itself A form of refractory support material containing a precious metal. Carrier coatings are known to those skilled in the art; they contain a coating comprising or consisting of precious metal-containing particles made from a refractory material which is calcined after application from a so-called carrier coating slurry.

The spent precious metal heterogeneous catalyst can be inherently granulated and sufficiently free of interfering impurities such that it can be directly treated according to step (2) of the process of the invention. If this is not the case, it may first be disintegrated (e.g., ground), and/or the undesirable impurities may be obtained from a suitable method known to those skilled in the art (e.g., by calcination with or without the addition of air). Remove. If applicable, a reduction treatment (for example, heat treatment in a reducing atmosphere) may be carried out to convert a noble metal which is not in elemental form, for example, in the form of a noble metal oxide in the particulate noble metal-containing refractory into an elemental noble metal.

In the step (2) of the process of the invention, the temperature is provided in the step (1) and the temperature is in the range of 200 ° C to 650 ° C, preferably 250 ° C to 600 ° C, especially 300 ° C to 500 ° C, and with the upward gas flow The granular noble metal-containing refractory material provided as a fluidized bed and chlorine, gaseous aluminum chloride and an inert gas (if applicable) are at a temperature of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C, especially from 300 ° C to 500 ° C. Contact in a hot fluidized bed.

The granulated noble metal-containing refractory material is supplied in the form of a fluidized bed by means of an upward gas flow, that is, it is fluidized. Methods and apparatus for forming a fluidized bed made from a particulate solid are known to those skilled in the art and do not require special measures, including in the case of granular precious metal-containing refractories. In particular, fluidization of particulate noble metal-containing refractories can be accomplished in conventional fluidized bed reactors. Conveniently, the apparatus or fluidized bed reactor used in this case has an inner wall and/or an inner liner which is resistant to chlorine and aluminum chloride at 200 ° C to 650 ° C, for example from quartz glass, nickel Base alloy (for example Hastelloy® C) or a suitable inorganic non-metallic refractory (eg graphite).

A fluidized bed reaction zone or at least one reaction zone.

In particular, examples of suitable inert gases are nitrogen and noble gases such as argon.

Chlorine and gaseous aluminum chloride are the active components.

The granulated noble metal-containing refractory material is heated to a temperature between 200 ° C and 650 ° C and transferred to a fluidized bed which also forms a reaction zone by means of an upward gas flow. This can occur in any time order or overlap in time. In particular, the method of heating the particulate noble metal-containing refractory material can occur by means of an upward gas stream heated to a corresponding temperature.

The chlorine, the optional inert gas and the gaseous aluminum chloride can each be supplied individually and/or or to the fluidized bed. In particular, the gas and/or the at least one gas mixture can be preheated upon supply. Gaseous aluminum chloride can also be formed in situ from a solid aluminum chloride mixed with a particulate noble metal-containing refractory material in a fluidized bed.

The upward gas stream may comprise or consist of chlorine, gaseous aluminum chloride, an optional inert gas, or a mixture of two or each of the components.

In a preferred embodiment of the process of the invention, the upward gas stream for forming a particulate noble metal-containing refractory material in the form of a fluidized bed comprises or consists essentially of gaseous aluminum chloride, chlorine and an inert gas (if applicable). The flow of the gas mixture. Thus, a stream comprising gaseous aluminum chloride, chlorine and an inert gas (if applicable) or a gas mixture consisting essentially of it is passed through a hot fluidized bed at a temperature of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C. Especially at temperatures between 300 ° C and 500 ° C. Preferably, the gas mixture supplied to the thermal reaction zone at a temperature of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C, especially from 300 ° C to 500 ° C, is hot, ie it is preheated to about 200 ° C to A temperature of 650 ° C, preferably 250 ° C to 600 ° C, especially 300 ° C to 500 ° C. In this way, the gas mixture can also be heated by the granular noble metal-containing refractory. The gas mixture can be produced separately. The gas mixture comprises gaseous aluminum chloride, chlorine and an inert gas (if applicable), preferably consisting essentially of gaseous aluminum chloride, chloride and an inert gas, if applicable. Preferably, the gas mixture contains an inert gas. The weight fraction of gaseous aluminum chloride in the gas mixture is, for example, in the range of 10% by weight to 80% by weight, preferably 30% by weight to 70% by weight, and the weight fraction of chlorine is, for example, 10% by weight to 40% by weight. %, preferably in the range of 15% by weight to 30% by weight, and the weight fraction of the inert gas is in the range of, for example, 0% by weight to 80% by weight, preferably 10% by weight to 50% by weight.

The fluidized bed and/or reaction zone is hot and has a temperature of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C, especially from 300 ° C to 500 ° C. All of the substances present in it, namely chlorine, gaseous aluminum chloride and particulate precious metal-containing refractories, and optional inert gases and reaction products produced in the reaction zone are at the same temperature prevailing in the reaction zone, at 200 From °C to 650 ° C, preferably from 250 ° C to 600 ° C, especially from 300 ° C to 500 ° C, or withstand this temperature. The gas stream provided and flowing through the fluidized bed and/or reaction zone may comprise, for example, 1 m ³ to 2.5 m per hour and per gram of granular precious metal-containing refractory material (ie, granular precious metal-containing refractory material per kg of reaction zone) Volume flow within the range of ³ .

In general, the overpressure is not dominant in the fluidized bed and/or reaction zone, and typically the pressure can range from atmospheric to about 1.5 times atmospheric.

The granular noble metal-containing refractory material and chlorine and gaseous aluminum chloride provided in the step (1) and having a temperature in the range of 200 ° C to 650 ° C, preferably 250 ° C to 600 ° C, especially 300 ° C to 500 ° C are at 200 ° C The contact in a hot fluidized bed at a temperature of 650 ° C, preferably 250 ° C to 600 ° C, especially 300 ° C to 500 ° C may begin when heating the particulate precious metal-containing refractory material, or may only be in the granular precious metal-containing refractory material Occurs when the desired temperature is reached.

Usually, the contact time and/or treatment time of the granular precious metal-containing refractory material with chlorine and gaseous aluminum chloride in the hot fluidized bed is appropriately selected, so as to ensure the precious metal self-granular precious metal-containing refractory material. Separate until the desired residual content or until the precious metal is absent (see the definition of "no precious metal" mentioned above). Typically, the necessary contact time and/or treatment time is in the range of, for example, 10 minutes to 240 minutes, especially 15 minutes to 120 minutes. To prevent any confusion, the contact time and/or treatment time of the particulate noble metal-containing refractory material corresponds to its residence time in the fluidized bed forming the reaction zone.

The process of the invention may be carried out in a batch process or in a continuous manner, but in the latter case it is preferred to adjust the chlorine and gaseous chlorination using a feed rate of the granular noble metal-containing refractory material through the fluidized bed forming the reaction zone. The time during which aluminum is contacted and/or treated with chlorine and gaseous aluminum chloride.

Conveniently, a space in which a granular noble metal-containing refractory material is heated is also used as a reaction zone. In other words, it is preferred to heat the particulate noble metal-containing refractory material in the reaction zone, i.e., in the fluidized bed and/or in the region filled by the fluidized bed. Therefore, the area of the fluidized bed reactor filled with a fluidized bed as mentioned above is a preferred reaction zone.

The reaction zone provided in the form of a fluidized bed has an inherently simple reaction system comprising and consisting essentially of reactants, precious metals, chlorine and gaseous aluminum chloride. The gas stream flowing through the fluidized bed flows through a fluidized refractory material containing a specific precious metal. Producing a compound containing gaseous aluminum, chlorine and a noble metal at a temperature in the range of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C, especially from 300 ° C to 500 ° C in the reaction zone, assuming that aluminum and precious metals are produced Chlorinated complex. The gaseous gas containing gaseous aluminum, chlorine and precious metals is carried away together with the hot gas stream directed from the reaction zone in the upward direction in step (3).

The provision of a granular noble metal-containing refractory material as a fluidized bed allows the achievement of the above-mentioned objectives, namely the efficient separation of precious metals from granular precious metal-containing refractories, and not only for the treatment of a large number of granular precious metal-containing refractories in a short period of time Objective, and with regard to achieving a uniform low residual precious metal content in the granular precious metal-containing refractories treated according to the invention (when in individual When considering the level of the grain, the goal is achieved. The process of the invention permits removal of greater than 99% by weight of precious metals initially present on and/or in the particulate noble metal-containing refractory.

In step (3), the gas stream, i.e., the gas stream that is flowing or has flowed through the fluidized bed forming the reaction zone, is directed away from the fluidized bed as it exits the fluidized bed. The gas stream exits the hot fluidized bed and/or reaction zone at a temperature of from 200 ° C to 650 ° C, preferably from 250 ° C to 600 ° C, especially from 300 ° C to 500 ° C, and can be conducted to allow for formation and deposition In the cooler regions of the solid precious metal chloride, for example, it is conducted to a region having an inner surface resistant to the gas stream component and having a temperature lower than that in the reaction zone. For example, the lower temperatures can range, for example, from 180 °C to <300 °C. At these lower temperatures, the aluminum, chlorine and noble metal-containing compounds carried together by the gas stream disintegrate while releasing the deposited precious metal chloride, while the inert gas, unused chlorine and gaseous aluminum chloride are further guided to ( For example) in a gas scrubber. Alternatively, the gas stream that has been removed and/or depleted of precious metal and/or precious metal chloride can be directed back to the fluidized bed to form a recycle system. In a fluidized bed, the desired gas composition can be adjusted by adding a chlorine fraction that is lost due to the consumption of chlorine and aluminum chloride (if applicable).

Depending in particular on the type of particulate noble metal-containing refractory material provided in step (1), the deposited noble metal chloride may be of a single type or may exist as a mixture of different precious metal chlorides. Examples of noble metal chlorides include PtCl ₂ , PdCl ₂ and RhCl ₃ . The separated precious metal chloride can be subjected to conventional reprocessing methods such as wet chemical reprocessing.

Instance Example 1

A gas mixture (67% by weight of gaseous aluminum chloride, 18% by weight of chlorine, 15% by weight of nitrogen) flowing through the reaction zone was used to make a total of 6,000 g of grinding catalyst (porous alumina carrier, platinum content 0.15% by weight) in the stream The bed reactor (60 cm long, at a temperature of 500 ° C, a cylindrical heat fluidized bed having a 15 cm inner diameter and/or a reaction zone) was fluidized for 60 minutes. The volume flow rate of the gas mixture was 9.4 m ³ /h. In the hot zone at a temperature of 200 ° C, a total of 76% of the platinum originally contained in the grinding catalyst (determined by means of ICP-OES) is recovered as PtCl ₂ from the gas leaving the reaction zone; 24% is initially contained in the grinding The platinum in the catalyst is left in the catalyst material (determined by ICP-MS after wet chemical digestion of the platinum depleted catalyst).

Reference example 2

Using a gas mixture flowing through the reaction zone (67% by weight gaseous aluminum chloride, 18% by weight chlorine, 15% by weight nitrogen) in a static tube furnace (75 cm long, at a temperature of 500 ° C, having a cylindrical inner diameter of 12 cm) A total of 6,000 g of grinding catalyst (porous alumina carrier, platinum content 0.15 wt%) was treated in the thermal reaction zone). The volumetric flow rate of the gas mixture is 70 liters/h. In the hot zone at a temperature of 200 ° C, the gas leaving the reaction zone recovers a total of 34% of the platinum originally contained in the grinding catalyst (determined by means of ICP-OES) in the form of PtCl ₂ ; 66% originally contained in The platinum in the grinding catalyst remains in the catalyst material (determined by ICP-MS after wet chemical digestion of the platinum depleted catalyst).

Example 3

Using a gas mixture (67 wt% gaseous aluminum chloride, 18 wt% chlorine, 15 wt% nitrogen) flowing through the reaction zone, a total of 6,000 g of grinding catalyst (porous alumina carrier, palladium content 0.15 wt%) was flowed The bed reactor (60 cm long, cylindrical hot fluidized bed with a 15 cm inner diameter and/or reaction zone at a temperature of 400 ° C) was fluidized for 60 minutes. The volume flow rate of the gas mixture was 9.4 m ³ /h. In the hot zone at a temperature of 200 ° C, the gas leaving the reaction zone recovers a total of 92% of palladium initially contained in the grinding catalyst (determined by ICP-OES) in the form of PdCl ₂ ; 8% originally contained in the grinding catalyst The palladium is left in the catalyst material (determined by ICP-MS after wet chemical digestion of the palladium depleted catalyst).

Reference example 4

A gas mixture (67 wt% gaseous aluminum chloride, 18 wt% chlorine, 15 wt% nitrogen) flowing through the reaction zone was used in a static tube furnace (75 cm long, at a temperature of 400 ° C, having a cylindrical inner diameter of 12 cm) A total of 6,000 g of grinding catalyst (porous alumina carrier, palladium content 0.1% by weight) was treated in the thermal reaction zone). The volumetric flow rate of the gas mixture is 70 liters/h. In the hot zone at a temperature of 200 ° C, a total of 81% of the palladium initially contained in the grinding catalyst (determined by ICP-OES) was recovered as PdCl ₂ from the gas leaving the reaction zone; 19% was originally contained in the grinding catalyst. The palladium is left in the catalyst material (measured by ICP-MS after wet chemical digestion of the palladium depleted catalyst).

Claims (10)

A method for separating precious metals from a granular noble metal-containing refractory material, comprising the steps of: (1) providing a granular noble metal-containing refractory material; (2) providing the temperature in the step (1) at 200 ° C to 650 ° C In the range, the granular noble metal-containing refractory material provided as a fluidized bed by means of the upward gas flow is contacted with chlorine and gaseous aluminum chloride and an inert gas (if applicable) in the hot fluidized bed at a temperature of 200 ° C to 650 ° C. And (3) directing the gas stream leaving the fluidized bed in an upward direction. The method of claim 1, wherein the upward gas stream comprises a stream of gaseous aluminum chloride, chlorine, and an inert gas (if applicable) or a gas mixture consisting of the same. The method of claim 1, wherein the noble metal of the granular noble metal-containing refractory material is at least one noble metal selected from the group consisting of silver, gold, ruthenium, osmium, iridium, osmium, platinum, palladium and iridium. The method of claim 1, wherein the precious metal content in the granular refractory material provided in the step (1) is in the range of 0.01% by weight to 10% by weight based on the total amount of the granular noble metal-containing refractory material . The method of claim 1, wherein the granular noble metal-containing refractory material is at least one material selected from the group consisting of disintegrated slag, precious metal slag, dried and disintegrated sludge, disintegration Waste electrical and electronic equipment, disintegrating mining concentrates, disintegrating mining waste and heterogeneous catalysts containing precious metals. The method of claim 1, wherein the fluidization of the particulate noble metal-containing refractory material occurs within the fluidized bed reactor. The method of claim 1, wherein the weight fraction of the gaseous aluminum chloride in the gas mixture is in the range of 10% by weight to 80% by weight, and the weight fraction of the chlorine is in the range of 10% by weight to 40% by weight and The inert gas has a weight fraction ranging from 0% by weight to 80% by weight. The method of claim 1, wherein the gas stream formed and flowing through the fluidized bed comprises a volumetric flow rate in the range of from 1 m ³ to 2.5 m ³ per kilogram of granular precious metal-containing refractory material. The method of claim 1, wherein the contact time of the granular noble metal-containing refractory material with chlorine and gaseous aluminum chloride in the hot fluidized bed is from 10 minutes to 240 minutes. The method of claim 1 wherein the gas stream exiting the fluidized bed is directed away into a relatively cold zone where solid precious metal chloride is allowed to form and deposit.