Method for recovering precious metal from refractory material

Abstract

The invention relates to a method for recovering precious metal from a refractory material, in particular to the field of secondary utilization of resources, and the method comprises the following steps: mixing refractory material powder with a dissolution agent, and introducing chlorine for dissolution to obtain a dissolution material; carrying out solid-liquid separation on the dissolved material to obtain a dissolved solution; the precious metal in the dissolved-out liquid is enriched, and a precious metal product is obtained; wherein the dissolving agent comprises concentrated hydrochloric acid, concentrated nitric acid, an oxidizing agent and water in a mass ratio of (2-3): 1: (0.5-1): (5-50). According to the method for recycling the precious metal from the refractory material, the specific dissolution agent is designed, meanwhile, by means of the matching effect of the introduced chlorine, efficient dissolution of precious metal elements in the refractory material is achieved, and secondary utilization of the precious metal in the refractory material is achieved.

Description

Technical Field

[0001] The present invention relates to the field of secondary utilization of resources, and particularly to a method for recovering precious metals from refractory materials. Background Art

[0002] Precious metals are scarce and valuable mineral resources with limited reserves. Due to their specific functions, they are widely used in various fields. During the processing and use of precious metal materials, they will inevitably come into contact with refractory materials. The recovery of precious metals in refractory materials is of great significance, which can avoid the loss of valuable metals and realize the secondary utilization of precious metals.

[0003] Currently, recycling useful resources from waste resources for secondary utilization is an important measure to achieve sustainable development. For example, CN109704791A discloses a method for recycling waste refractory materials, including the following steps: (1) material selection; (2) coarse crushing; (3) fine crushing; (4) iron removal; (5) batching; (6) high-pressure molding. This recycling method can reuse waste refractory materials to make recycled refractory bricks, avoiding the occupation of land by landfilling waste refractory materials.

[0004] CN101397608A is a method for enriching and recovering metal platinum and rhodium from waste refractory materials. The surface layer of the waste refractory material accumulated with metal platinum and rhodium is soaked in hydrofluoric acid for acid etching. After the surface layer is soaked until it becomes loose, it is taken out. After neutralization, the surface layer is scraped, and the scraped material is washed with water to obtain mixed concentrate sand. After screening the mixed concentrate sand, the concentrate sand enriched with platinum and rhodium is obtained, and then platinum and rhodium metals are extracted from the concentrate sand by chemical purification method.

[0005] CN115572815A is a method for recovering platinum from a platinum-containing broken crucible, which includes the following steps: Step 1, break the platinum-containing crucible and react with hydrazine hydrate, and filter the broken pieces; Step 2, react the broken pieces with nitric acid and hydrochloric acid to produce platinum-rich solution; Step 3, drive the nitric acid in the platinum-rich solution until there is no yellow smoke, stop heating, weigh and assay the platinum-rich solution after cooling to room temperature quickly; Step 4, heat the platinum-rich solution and add ammonium chloride while stirring until no ammonium chloroplatinate precipitate is formed, filter, wash with ammonium chloride water until the filtrate is clear, add sodium hydroxide to the residue after washing ammonium chloroplatinate to adjust the pH, heat, add hydrazine hydrate to obtain platinum powder, filter, wash until neutral, and dry; Step 5, wash the platinum powder twice with hot water, filter the supernatant, then add hydrochloric acid for washing. The washing process is carried out in an ultrasonic wave, control the oxidation potential, wash, and pour out the upper clear liquid after standing to obtain the filter residue. Wash the filter residue with hot water until the supernatant is neutral, filter, and take a platinum powder sample for detection.

[0006] In summary, when the refractory material is recycled at present, it mainly includes secondary forming and the recycling of precious metals. However, when recycling precious metals from refractory materials, there are still defects such as poor dissolution effect of precious metals, which is not conducive to the recycling of precious metals. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for recovering precious metals from refractory materials, so as to solve the defects that when recycling precious metals from refractory materials, there are still poor dissolution effects of precious metals, which is not conducive to the recycling of precious metals.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for recovering precious metals from refractory materials, and the method for recovering precious metals from refractory materials includes:

[0010] Mix the refractory material powder with a leaching agent and introduce chlorine gas for leaching to obtain a leached material;

[0011] Perform solid-liquid separation on the leached material to obtain a leachate;

[0012] Enrich the precious metals in the leachate to obtain precious metal products;

[0013] Among them, the leaching agent includes: concentrated hydrochloric acid, concentrated nitric acid, an oxidant, and water with a mass ratio of (2-3):1:(0.5-1):(5-50).

[0014] The method for recovering precious metals from refractory materials provided by the present invention realizes the efficient dissolution of precious metal elements in refractory materials through the design of a specific leaching agent and with the cooperation effect of introducing chlorine gas, which is conducive to the secondary utilization of precious metals in refractory materials.

[0015] As a preferred technical solution of the present invention, the refractory material powder is obtained by crushing and / or grinding the refractory material.

[0016] Preferably, the particle size of the refractory material powder is ≤3 mm.

[0017] Preferably, the oxidant includes: hydrogen peroxide solution and / or sodium hypochlorite.

[0018] As a preferred technical solution of the present invention, the solid-liquid ratio of the refractory material powder to the leaching agent is 1:(1.5-4) g / mL.

[0019] As a preferred technical solution of the present invention, the chlorine gas is introduced in the form of microbubbles.

[0020] Preferably, the diameter of the microbubbles is 10-30 μm.

[0021] As a preferred technical solution of the present invention, the feeding rate of chlorine gas is 0.5 - 3 mL / min.

[0022] As a preferred technical solution of the present invention, stirring with a rotation speed of 30 - 200 r / min is assisted during the dissolution.

[0023] As a preferred technical solution of the present invention, the temperature of the dissolution is ≥ 80 °C.

[0024] As a preferred technical solution of the present invention, the time of the dissolution is ≥ 30 min.

[0025] As a preferred technical solution of the present invention, the methods of solid-liquid separation include: one or a combination of at least two of filtration, suction filtration, pressure filtration, or centrifugation.

[0026] As a preferred technical solution of the present invention, the methods of enrichment include: one or a combination of at least two of metal simple substance replacement, extraction, ion exchange, or precipitation.

[0027] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0028] The process provided by the present invention, through adopting a dissolution process with a specific design and by means of the intensifying effect of microbubble chlorine gas, realizes the efficient dissolution of precious metal elements in refractory materials, ensures the effective recovery of precious metals, significantly shortens the production cycle, is convenient to operate, realizes the secondary utilization of precious metals with low cost and high value, and the recovery rate of precious metals is ≥ 98%. Specific Embodiments

[0029] To better illustrate the present invention and facilitate the understanding of its technical solutions, the typical but non-limiting embodiments of the present invention are as follows:

[0030] This embodiment provides a method for recovering precious metals from refractory materials. The method for recovering precious metals from refractory materials includes:

[0031] Mix the refractory material powder with a dissolution agent and introduce chlorine gas for dissolution to obtain a dissolved material;

[0032] Perform solid-liquid separation on the dissolved material to obtain a dissolved solution;

[0033] Enrich the precious metals in the dissolved solution to obtain a precious metal product;

[0034] Among them, the dissolution agent includes: concentrated hydrochloric acid, concentrated nitric acid, an oxidizing agent, and water with a mass ratio of (2 - 3):1:(0.5 - 1):(5 - 50).

[0035] In the present invention, refractory materials refer to a class of inorganic non-metallic materials with a refractoriness of not less than 1580 °C, such as refractory bricks, crucibles, ceramics, etc. The noble metal elements in refractory materials, such as platinum, rhodium, palladium, iridium, gold, and silver, are noble metals commonly used to enhance properties or noble metals combined with refractory materials during their use.

[0036] In the present invention, the mass ratio of concentrated hydrochloric acid, concentrated nitric acid, oxidant, and water in the leaching agent is (2 - 3):1:(0.5 - 1):(5 - 50). For example, it can be 2:1:0.5:5, 2.5:1:1:5, 3:1:0.5:10, 2:1:1:20, 3:1:1:5, 3:1:1:10, 2.5:1:0.75:20, 2:1:1:30, 2:1:1:40, 2:1:1:50, 3:1:0.5:15, 3:1:0.5:20, 3:1:0.5:30, or 3:1:0.5:50, etc., but is not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0037] In the present invention, the mass concentration of concentrated hydrochloric acid is 36 - 38%. For example, it can be 36%, 36.5%, 37%, 37.5%, or 38%, etc., but is not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0038] In the present invention, the mass concentration of concentrated nitric acid is 86 - 97.5%. For example, it can be 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 97.5%, etc., but is not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0039] Among them, the refractory material powder is obtained by crushing and / or grinding the refractory material.

[0040] In the present invention, crushing refers to single-stage or multi-stage crushing using a jaw crusher, cone crusher, etc. to obtain refractory materials within the target particle size range.

[0041] In the present invention, grinding refers to single-stage or multi-stage grinding using equipment such as ball mills, rod mills, pebble mills, autogenous mills, etc. to obtain refractory materials within the target particle size range.

[0042] In the present invention, when pulverizing waste refractory materials, an efficient pulverization can also be achieved by combining crushing and grinding.

[0043] Among them, the particle size of the refractory material powder ≤ 3 mm.

[0044] In the present invention, the particle size of the refractory powder refers to an aggregate of single-sized particles within a particle size range or an aggregate of all particles within a certain range. Exemplarily, it can be an aggregate of particles with a particle size ≤ 2 mm, an aggregate of particles with a particle size ≤ 1 mm, an aggregate of particles with a particle size ≤ 0.5 mm, an aggregate of all particles within the range of 1 - 2 mm in particle size, an aggregate of all particles within the range of 0.1 - 3 mm in particle size, an aggregate of all particles within the range of 0.01 - 0.5 mm in particle size, an aggregate of particles with a particle size of 3 mm, an aggregate of particles with a particle size of 1 mm, an aggregate of particles with a particle size of 2 mm, an aggregate of particles with a particle size of 0.1 mm, etc.

[0045] Among them, the oxidant includes: hydrogen peroxide solution and / or sodium hypochlorite.

[0046] In this solution, the mass concentration of the hydrogen peroxide solution used is 20 - 30%, and the solute can be selected as a solvent such as water that does not affect the use performance of the leaching agent.

[0047] Among them, the solid-liquid ratio g / mL of the refractory powder and the leaching agent is 1:(1.5 - 4). For example, it can be 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, or 1:4, etc., but not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0048] Among them, the chlorine gas is introduced in the form of microbubbles.

[0049] Among them, the diameter of the microbubbles is 10 - 30 μm. For example, it can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, or 30 μm, etc., but not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0050] Among them, the introduction rate of the chlorine gas is 1.5 - 3 mL / min. For example, it can be 1.5 mL / min, 1.6 mL / min, 1.7 mL / min, 1.8 mL / min, 1.9 mL / min, 2 mL / min, 2.2 mL / min, 2.4 mL / min, 2.6 mL / min, 2.8 mL / min, or 3 mL / min, etc., but not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0051] Among them, stirring at a rotation speed of 30 - 200 r / min is assisted during the dissolution. For example, it can be 30 r / min, 40 r / min, 50 r / min, 60 r / min, 70 r / min, 80 r / min, 90 r / min, 100 r / min, 110 r / min, 120 r / min, 130 r / min, 140 r / min, 150 r / min, 160 r / min, 170 r / min, 180 r / min, 190 r / min or 200 r / min, etc., but not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0052] Among them, the temperature of the dissolution is ≥80°C. For example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, but not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0053] Among them, the time of the dissolution is ≥30 min. For example, it can be 30 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min, 200 min, 220 min or 240 min, etc., but not limited to the listed values. Other unlisted values within this range also meet the requirements.

[0054] Among them, the methods of solid-liquid separation include: one or a combination of at least two of filtration, suction filtration, pressure filtration or centrifugation.

[0055] Exemplarily, combinations of solid-liquid separation such as: a combination of filtration and suction filtration, a combination of suction filtration and pressure filtration, a combination of pressure filtration and centrifugation, a combination of filtration and centrifugation, etc.

[0056] Among them, the methods of enrichment include: one or a combination of at least two of metal elemental replacement, extraction, ion exchange or precipitation.

[0057] In the present invention, when the enrichment effect is affected by the complexation and other effects of metal elements in the solution during enrichment, operations such as breaking the complex and removing nitrate can be selected to ensure the enrichment effect.

[0058] In the present invention, metal elemental replacement refers to using a relatively active metal element to displace a relatively inert metal element from the liquid phase according to the metal activity series to achieve the replacement of precious metals. For example, iron or zinc is used for replacement. Iron can be iron blocks or iron powder, and zinc can be zinc blocks or zinc powder.

[0059] In the present invention, extraction refers to using common organic extractants in the art such as neutral extractants, acidic extractants, basic extractants, chelating extractants, etc.

[0060] Exemplarily, combinations of enrichment methods include: combinations of metallic element replacement and extraction, combinations of extraction and ion exchange, combinations of ion exchange and precipitation, combinations of extraction and precipitation, etc.

[0061] Further, in order to illustrate the good recovery effect that can be achieved by the method for recovering precious metals from refractory materials provided by the present invention, the following actual examples are used for illustration, specifically as follows:

[0062] In the following examples, the refractory materials used are from crucible materials in the process of precious metal processing and smelting and refractory materials in direct contact with precious metals during the use of precious metals, and specifically contain the following precious metal elements: platinum, rhodium, palladium, iridium, gold and silver.

[0063] Example 1

[0064] This example provides a method for recovering precious metals from refractory materials, specifically as follows:

[0065] Mix refractory material powder (particle size ≤ 3 mm) with a leaching agent (concentrated hydrochloric acid with a mass concentration of 37%, concentrated nitric acid with a mass concentration of 90%, hydrogen peroxide solution with a mass concentration of 25% and water in a mass ratio of 3:1:0.6:30) at a solid-liquid ratio of mg / L of 1:4, and introduce chlorine gas (introduced in the form of microbubbles with a diameter of 20 - 30 μm and an introduction rate of 3 mL / min) for leaching. Stirring is assisted during leaching at a rotation speed of 150 r / min, the leaching temperature is 80 °C, and the time is 30 min to obtain a leached material;

[0066] Filter the leached material to obtain a leachate;

[0067] Enrich the precious metals in the leachate, specifically by using elemental iron for replacement to obtain precious metal products.

[0068] Example 2

[0069] This example provides a method for recovering precious metals from refractory materials, specifically as follows:

[0070] Mix refractory material powder (particle size of 0.1 - 3 mm) with a leaching agent (concentrated hydrochloric acid with a mass concentration of 36%, concentrated nitric acid with a mass concentration of 86%, hydrogen peroxide solution with a mass concentration of 28% and water in a mass ratio of 2.5:1:0.8:15) at a solid-liquid ratio of mg / L of 1:2, and introduce chlorine gas (introduced in the form of microbubbles with a diameter of 10 - 20 μm and an introduction rate of 0.5 mL / min) for leaching. Stirring is assisted during leaching at a rotation speed of 100 r / min, the leaching temperature is 85 °C, and the time is 40 min to obtain a leached material;

[0071] Filter the leached material to obtain a leachate;

[0072] Enrich the precious metals in the leaching solution, specifically by using elemental iron for replacement to obtain precious metal products.

[0073] Example 3

[0074] This example provides a method for recovering precious metals from refractory materials, specifically as follows:

[0075] Mix refractory material powder (particle size 0.5 - 2 mm) with a leaching agent (concentrated hydrochloric acid with a mass concentration of 39%, concentrated nitric acid with a mass concentration of 97.5%, hydrogen peroxide solution with a mass concentration of 20%, and water in a mass ratio of 2:1:0.5:5) at a solid-liquid ratio of mg / L of 1:1.5, and introduce chlorine gas (introduced in the form of microbubbles with a diameter of 15 - 20 μm and an introduction rate of 3 mL / min) for leaching. Stirring is assisted during leaching at a rotation speed of 30 r / min, the leaching temperature is 90°C, and the time is 60 min to obtain a leached material;

[0076] Filter the leached material to obtain a leaching solution;

[0077] Enrich the precious metals in the leaching solution, specifically by using elemental iron for replacement to obtain precious metal products.

[0078] Example 4

[0079] This example provides a method for recovering precious metals from refractory materials, specifically as follows:

[0080] Mix refractory material powder (particle size 0.01 - 1.5 mm) with a leaching agent (concentrated hydrochloric acid with a mass concentration of 37.5%, concentrated nitric acid with a mass concentration of 92%, hydrogen peroxide solution with a mass concentration of 30%, and water in a mass ratio of 3:1:1:50) at a solid-liquid ratio of mg / L of 1:3, and introduce chlorine gas (introduced in the form of microbubbles with a diameter of 18 - 25 μm and an introduction rate of 2.5 mL / min) for leaching. Stirring is assisted during leaching at a rotation speed of 200 r / min, the leaching temperature is 90°C, and the time is 50 min to obtain a leached material;

[0081] Centrifuge the leached material to obtain a leaching solution;

[0082] Enrich the precious metals in the leaching solution, specifically by using elemental zinc for replacement to obtain precious metal products.

[0083] Example 5

[0084] The difference from Example 1 is only that the hydrogen peroxide solution in the leaching agent is replaced with an equal amount of sodium hypochlorite.

[0085] Example 6

[0086] It is only different from Example 1 in that chlorine gas is directly introduced into the solution through a gas pipe with a diameter of 8 mm.

[0087] Example 7

[0088] It is only different from Example 1 in that the diameter of the microbubbles is 50 - 80 μm.

[0089] Comparative Example 1

[0090] It is only different from Example 1 in that the concentrated hydrochloric acid in the solvent is replaced with concentrated nitric acid of equal amount and concentration.

[0091] Comparative Example 2

[0092] It is only different from Example 1 in that the concentrated hydrochloric acid in the solvent is replaced with a hydrogen peroxide solution of equal amount and concentration.

[0093] Comparative Example 3

[0094] It is only different from Example 1 in that the concentrated nitric acid in the solvent is replaced with concentrated hydrochloric acid with a mass concentration of 38% of equal amount.

[0095] Comparative Example 4

[0096] It is only different from Example 1 in that the concentrated nitric acid in the solvent is replaced with a hydrogen peroxide solution with a concentration of 30% of equal amount.

[0097] Comparative Example 5

[0098] It is only different from Example 1 in that the mass ratio of concentrated hydrochloric acid, concentrated nitric acid, hydrogen peroxide solution and water in the solvent is 3:1:0.2:30.

[0099] Comparative Example 6

[0100] It is only different from Example 1 in that the mass ratio of concentrated hydrochloric acid, concentrated nitric acid, hydrogen peroxide solution and water in the solvent is 1.5:1:0.6:30.

[0101] The noble metal elements in the leaching solutions obtained from the above examples and comparative examples were tested. Combining with the content of noble metal elements in the refractory powder, the leaching rate of noble metal elements was calculated. Further combining with the mass of the noble metal products obtained by enrichment, the recovery rate of the recovered noble metals was calculated. The specific results are shown in Table 1 below.

[0102] Table 1

[0103]

[0104]

[0105] The method for recovering precious metals from refractories provided by the present invention realizes the efficient dissolution of precious metal elements in refractories by designing a specific leaching agent and with the assistance of the cooperative effect of introducing chlorine gas, which is beneficial to the secondary utilization of precious metals in refractories.

[0106] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0107] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0108] Furthermore, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for recovering precious metals from refractory materials, characterized in that, The method for recovering precious metals from refractory materials comprises the following steps: Mix the refractory material powder with a leaching agent and introduce chlorine gas for leaching to obtain a leached material; Perform solid-liquid separation on the leached material to obtain a leaching solution; Enrich the precious metals in the leaching solution to obtain precious metal products; Among them, the leaching agent comprises concentrated hydrochloric acid, concentrated nitric acid, an oxidizing agent and water with a mass ratio of (2-3):1:(0.5-1):(5-50).

2. The method for recovering precious metals from refractory materials according to claim 1, characterized in that, The refractory material powder is obtained by crushing and / or grinding the refractory material; Preferably, the particle size of the refractory material powder is ≤3 mm; Preferably, the oxidizing agent comprises hydrogen peroxide solution and / or sodium hypochlorite.

3. The method for recovering precious metals from refractories according to claim 1, characterized in that, The solid-liquid ratio of the refractory material powder to the leaching agent is 1:(1.5-4) g / mL.

4. The method for recovering precious metals from refractory materials according to claim 1, characterized in that, The chlorine gas is introduced in the form of microbubbles; Preferably, the diameter of the microbubbles is 10-30 μm.

5. The method for recovering precious metals from refractories according to claim 1, characterized in that, The introduction rate of the chlorine gas is 0.5-3 mL / min.

6. The method for recovering precious metals from refractory materials according to claim 1, characterized in that, Stirring with a rotation speed of 30-200 r / min is assisted during the leaching process.

7. The method for recovering precious metals from refractory materials according to claim 1, characterized in that, The temperature of the leaching process is ≥80 °C.

8. The method for recovering precious metals from refractory materials according to claim 1, characterized in that, The time of the leaching process is ≥30 min.

9. The method for recovering precious metals from refractories according to claim 1, characterized in that, The methods for solid-liquid separation include one or a combination of at least two of filtration, suction filtration, pressure filtration or centrifugation.

10. The method for recovering precious metals from refractory materials according to claim 1, characterized in that, The methods for enrichment include one or a combination of at least two of metal single displacement, extraction, ion exchange or precipitation.

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