Non-aqua regia gold extraction agent and method for recovering precious metal from waste containing precious metal

Abstract

The invention discloses a non-aqua regia gold extraction agent and method for recovering precious metal from waste containing precious metal. The non-aqua regia gold extraction agent is composed of nitrate, metal chloride and weak acid, by precisely regulating and controlling the concentrations of nitrate, chloride ions and hydrogen ions in the non-aqua regia gold extraction agent, the precious metal in the waste containing the precious metal can be subjected to green, efficient and selective oxidation leaching under the normal temperature condition, the precious metal ions in the leaching solution are subjected to reduction operation, and therefore the recovery rate of the precious metal in the waste containing the precious metal is improved. And a pure noble metal product can be obtained. Compared with a traditional aqua regia method, the method has the advantages that strong acid reagents such as concentrated nitric acid and concentrated hydrochloric acid are not used, corrosion to equipment and operation risks are remarkably reduced, and secondary emission of harmful gas is avoided. The method has the remarkable advantages of being environmentally friendly, easy and convenient to operate, mild in reaction condition, low in equipment requirement, high in leaching rate and the like, is suitable for large-scale and industrial production, and has wide application prospects and commercial value in the field of precious metal recovery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrometallurgy and precious metal recovery, and specifically relates to a non-aqua regia gold extraction agent composed of nitrate, metal chloride and weak acid, which can realize green, efficient and selective recovery of precious metals from waste materials containing precious metals. BACKGROUND

[0002] In the current situation of the iteration cycle of smart phones being shortened to 18 months and the annual shipment of smart wearable devices breaking 1 billion units, global electronic products are being updated and replaced at an astonishing speed. This wave of high-speed popularization and iteration upgrade directly leads to an explosive growth trend in the production of waste materials containing precious metals. According to statistics from the International Electronics Waste Association, the total amount of global electronic waste in 2023 reached 53.6 million tons, of which waste materials containing precious metals accounted for more than 15%, forming a large and continuously expanding "urban mine".

[0003] These seemingly useless electronic waste actually contains amazing wealth: each ton of waste mobile phone circuit board contains 150 grams of gold, which is 500 times the grade of ordinary gold ore; the content of precious metals such as platinum, palladium and rhodium in waste automobile exhaust catalysts is as high as 1% to 3%. However, the current extensive disposal method is exacerbating resource waste and environmental crisis.

[0004] The current mainstream recovery of precious metals technologies such as cyanide method and pyrometallurgical smelting are like a poison to quench thirst. Although cyanide method can efficiently dissolve gold, it consumes 3 to 5 kilograms of highly toxic cyanide per ton of waste, with a high risk of leakage; pyrometallurgical smelting requires operation at a high temperature of 1200℃ or above, with energy consumption equivalent to 3 times that of the production of the same weight of gold, and releases a large amount of sulfur dioxide, dioxin and other pollutants. More worrying is that the recovery rate of these traditional processes for rhodium, iridium and other rare precious metals is less than 60%, causing secondary waste of resources.

[0005] Under the dual driving of the "double carbon" goal and the circular economy strategy, the research and development of green recycling technology has risen to the core competitiveness of the country. By 2025, the resource utilization rate of electronic waste should be increased to 75%, and 50 "urban mine" demonstration bases should be established. Under this background, the research and development of new gold extraction agents for precious metals is not only the "golden key" to solving the resource bottleneck, but also the key to realizing the win-win of environmental and economic benefits.

[0006] The document "Dissolution of noble metals in highly concentrated acidic salt solutions" mentions the use of high concentrations of aluminum nitrate and aluminum chloride to achieve the extraction of the noble metal palladium in 80℃ for 15 minutes, while the extraction time of platinum and gold is longer, even more than 24 hours, and the extraction of rhodium is affected by solubility, so that the extraction efficiency of the noble metal is low. CN117926022A discloses a non-cyanide trans-gold extraction agent and application. The gold extraction agent is combined with water-soluble iron salt and weak acid to remove active metals in gold-containing materials, and then to retain noble metals. The gold extraction agent can achieve the purpose of green and efficient recovery of noble metals, but there is a problem of difficult separation of unreacted noble metals and non-metal materials. SUMMARY

[0007] Based on the current status of noble metal-containing waste recovery at home and abroad, the present application provides a non-aqua regia gold extraction agent which is green, easy to operate, mild in reaction conditions, low in equipment requirements, and high in noble metal leaching rate.

[0008] The non-aqua regia gold extraction agent for recovering noble metals from noble metal-containing waste provided by the present application is composed of nitrate, metal chloride and weak acid, and the concentration of nitrate in the non-aqua regia gold extraction agent is 0.2-2.0 mol / L, the concentration of chloride ion is 0.4-6.0 mol / L, and the concentration of hydrogen ion is 0.4-4.0 mol / L.

[0009] Further, the concentration of nitrate in the above-mentioned non-aqua regia gold extraction agent is preferably 0.4-1.5 mol / L, the concentration of chloride ion is 1.2-4.5 mol / L, and the concentration of hydrogen ion is 0.8-3.0 mol / L.

[0010] Further, the concentration of nitrate in the above-mentioned non-aqua regia gold extraction agent is more preferably 0.6-1.0 mol / L, the concentration of chloride ion is 1.8-3.0 mol / L, and the concentration of hydrogen ion is 1.2-2.0 mol / L.

[0011] Further, the above-mentioned nitrate includes but is not limited to any one or more of lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, aluminum nitrate, ferrous nitrate, ferric nitrate, copper nitrate, zinc nitrate, silver nitrate, palladium nitrate, and bismuth nitrate.

[0012] Further, the above-mentioned metal chloride includes but is not limited to any one or more of sodium chloride, potassium chloride, lithium chloride, magnesium chloride, calcium chloride, aluminum chloride, ferric chloride, ferrous chloride, copper chloride, zinc chloride, manganese chloride, nickel chloride, silver chloride, palladium chloride, and platinum chloride.

[0013] Further, the weak acid includes, but is not limited to, any one or more of carbonic acid, silicic acid, boric acid, phosphoric acid, sulfurous acid, hydrogen sulfide, hypochlorous acid, acetic acid, propionic acid, citric acid, lactic acid, malic acid, tartaric acid, and amino acid.

[0014] The application also provides a method for recovering precious metals from waste materials containing precious metals, which comprises: classifying the waste materials containing precious metals according to the metal components and grades, adding the classified waste materials into the non-aqua regia gold extraction agent, and preparing the non-aqua regia gold extraction agent containing different concentrations of nitrate, chloride and hydrogen ions for different metal elements, and stirring at room temperature for 1-10 hours to oxidize and leach precious metals (such as Au 0 ) and obtain a solution containing precious metal ions (such as Au 3+ ), and reducing the precious metal ions (such as Au 3+ ) in the solution into precious metal elements (such as gold element) to obtain the final precious metal product.

[0015] Further, in the method for recovering precious metals from waste materials containing precious metals, the solid-liquid ratio of the waste materials containing precious metals to the non-aqua regia gold extraction agent is preferably 1:10-1:100 g / mL, and further preferably 1:20-1:80 g / mL.

[0016] Further, the waste materials containing precious metals include, but are not limited to, electronic waste and ore powder, and the electronic waste includes, but is not limited to, any one or more of gold-plated contacts of computer mainboards, CPUs and memory sticks, memory stick pins, mobile phone mainboard chip pins, router network port gold-plated contacts, digital camera lens module contacts, game console mainboard interfaces, industrial control board connectors, medical instrument electrode sheet gold-plated components, integrated circuit chip pins, relay gold-plated contacts, and platinum-rhodium materials in sensors; and the ore powder includes, but is not limited to, any one or more of gold ore powder, silver ore powder, platinum group metal ore powder, placer gold ore powder, electronic waste ore powder, automobile catalyst ore powder, chemical waste ore powder, electroplating waste ore powder, jewelry processing waste ore powder, and ore powder containing iridium and osmium and other rare precious metals.

[0017] The non-aqua regia gold extraction agent of the application mainly oxidizes and leaches the precious metals in the waste materials containing precious metals to obtain a solution containing precious metal ions, and further reduces the solution to obtain a precious metal product. The chemical reactions involved in the process are as follows (taking gold as an example):

[0018]

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. The non-aqua regia gold extraction agent of the present application mainly comprises nitrate, metal chloride and weak acid. According to the different metal elements and grades contained in the waste material containing precious metals, appropriate concentrations of nitrate, metal chloride and weak acid are selected, and the precious metals in the waste material containing precious metals can be quickly recovered at room temperature. The gold leaching efficiency can be comparable to that of the traditional aqua regia method, while the equipment corrosion and harmful gas emission are greatly reduced, showing excellent safety, environmental protection and industrial application potential.

[0021] 2. The present application realizes an innovative breakthrough in gold extraction process. The precious metals are extracted into the non-aqua regia gold extraction agent solution by using nitrate, metal chloride and weak acid, and high-purity precious metals can be further obtained through reduction reaction. The limitations of thiosulfate and thiourea non-cyanide methods such as low leaching rate, strong temperature dependence, slow leaching rate, high cost and poor raw material adaptability are effectively overcome. In addition, the present application eliminates the production problems and safety hazards caused by harmful gases generated in the traditional gold extraction process. Compared with the existing mainstream gold extraction technology, the present application is simple to operate and does not require special equipment, which can significantly reduce the recovery cost and has great advantages in safety and environmental protection. The present application has far-reaching strategic significance for the continuous innovation of precious metal recovery technology.

[0022] 3. The gold leaching method proposed by the present application mainly uses salt solution to realize green and efficient extraction of precious metals such as gold from waste material containing precious metals, with a gold leaching rate of more than 95%. Compared with the traditional aqua regia method, the present application can quickly extract various precious metals at low concentration and at ambient temperature, which not only conforms to the principle of green chemistry and avoids pollution to the environment and ecology, but also realizes efficient recovery of gold under relatively mild conditions, reduces energy consumption and pollution emissions, and truly transforms "urban mines" into a green treasure trove for sustainable development. The method is beneficial to large-scale production and has broad prospects in industrial application, providing a new technical path for green recovery of waste material containing precious metals, and has important academic value and practical application significance. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 EDX element analysis of the CPU pin containing precious metals used in Examples 1-6 and Examples 8-10. Wherein a is the external element analysis and content of CPU, and b is the internal element analysis and content of CPU.

[0024] Figure 2 The influence of the type of nitrate in the non-aqua regia gold extraction agent of Example 1 on the gold leaching rate in CPU.

[0025] Figure 3 The influence of the type of metal chloride in the non-aqua regia gold extraction agent of Example 2 on the gold leaching rate in CPU.

[0026] Figure 4 Effect of weak acid type in non-aqua regia gold extraction reagent of Example 3 on gold leaching rate in CPU.

[0027] Figure 5 Effect of different iron nitrate concentrations in non-aqua regia gold extraction reagent of Example 4 on gold leaching rate in CPU.

[0028] Figure 6 Effect of different iron chloride concentrations in non-aqua regia gold extraction reagent of Example 5 on gold leaching rate in CPU.

[0029] Figure 7 Effect of solid-liquid ratio of non-aqua regia gold extraction reagent of Example 6 to CPU pins on gold leaching rate.

[0030] Figure 8 Effect of non-aqua regia gold extraction reagent of Example 7 on the leaching rate of precious metals in different types of precious metal-containing waste materials.

[0031] Figure 9 Effect of non-aqua regia gold extraction reagent of Example 8 on gold leaching rate in CPU at different reaction times.

[0032] Figure 10 Effect of non-aqua regia gold extraction reagent of Example 9 on gold leaching rate in CPU at different reaction temperatures.

[0033] Figure 11 Optical images of CPU before and after treatment with non-aqua regia gold extraction reagent of Example 10. Wherein a is before treatment (contains CPU pins), b is after treatment (only non-metallic part is left), c is the extraction liquid of CPU treated with non-aqua regia gold extraction reagent, d is sponge gold after reduction and smelting gold photos and elemental analysis. DETAILED DESCRIPTION

[0034] The technical solutions of the present application are further illustrated below in conjunction with the drawings and examples, but the protection scope of the present application is not limited to these examples.

[0035] The following examples, unless otherwise specified, the selected precious metal-containing waste materials are all CPUs. We have carried out elemental analysis on CPU, from which we can see that the outer coating of CPU is gold and nickel, and the internal conductive medium is copper. Among them, copper and nickel are active metals, and gold is an inert metal. Figure 1

[0036] All leaching rates are calculated based on the total amount of each metal content after aqua regia treatment.

[0037] Example 1

[0038] Effect of different nitrate salts in non-aqua regia gold extraction reagent on gold leaching rate in CPU

[0039] ​To 20 mL of acetic acid, iron chloride was added, and lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, aluminum nitrate, ferrous nitrate, ferric nitrate, copper nitrate, zinc nitrate, silver nitrate, palladium nitrate, bismuth nitrate were added respectively, three samples in parallel for each nitrate, magnetic stirring until completely dissolved, to obtain a non-aqua regia gold extraction agent, control the concentration of nitrate in the non-aqua regia gold extraction agent to be 0.9 mol / L, the concentration of chloride ions to be 2.7 mol / L, and the concentration of hydrogen ions to be 1.8 mol / L. 1 g of CPU pin was added to the above non-aqua regia gold extraction agent respectively, the solid-liquid ratio was 1:20 g / mL, and the reaction was stirred at room temperature for 3 hours. Filtration was performed using a 0.22 μm filter, and 0.5 mL of filtrate was diluted and then the gold content in the diluted solution was detected by ICP-OES.

[0040] It can be seen that the selection of different nitrates in the non-aqua regia gold extraction agent can achieve an leaching rate of gold in CPU of more than 90%, among which the leaching rate of gold in CPU is optimal when the nitrate is ferric nitrate. Figure 2 Example 2

[0041] Effect of different metal chlorides in non-aqua regia gold extraction agent on gold leaching rate in CPU containing precious metal waste

[0042] To 20 mL of acetic acid, iron chloride was added, and sodium chloride, potassium chloride, lithium chloride, magnesium chloride, calcium chloride, aluminum chloride, ferric chloride, ferrous chloride, copper chloride, zinc chloride, manganese chloride, nickel chloride, silver chloride, palladium chloride, platinum chloride were added respectively, three samples in parallel for each metal chloride, magnetic stirring until completely dissolved, to obtain a non-aqua regia gold extraction agent, control the concentration of nitrate in the non-aqua regia gold extraction agent to be 0.9 mol / L, the concentration of chloride ions to be 2.7 mol / L, and the concentration of hydrogen ions to be 1.8 mol / L. 1 g of CPU pin was added to the above non-aqua regia gold extraction agent respectively, the solid-liquid ratio was 1:20 g / mL, and the reaction was stirred at room temperature for 3 hours. Filtration was performed using a 0.22 μm filter, and 0.5 mL of filtrate was diluted and then the gold content in the diluted solution was detected by ICP-OES.

[0043] It can be seen that the selection of different metal chlorides in the non-aqua regia gold extraction agent can achieve an leaching rate of gold in CPU of more than 90%, among which the leaching rate of gold in CPU is optimal when the metal chloride is ferric chloride.

[0044] Figure 3 Example 3

[0045] Effect of different weak acids in non-aqua regia gold extraction agent on gold leaching rate in CPU containing precious metal waste

[0046]

[0047] ​​20mL of carbonic acid, silicic acid, boric acid, phosphoric acid, sulfurous acid, hydrosulfuric acid, hypochlorous acid, acetic acid, propionic acid, citric acid, lactic acid, malic acid, tartaric acid, and amino acids were used as weak acids. Ferric nitrate and ferric chloride were added to the weak acids. Three samples of each weak acid were prepared in parallel. After magnetic stirring until completely dissolved, a non-aqua regia gold extracting agent was obtained. The concentration of nitrate in the non-aqua regia gold extracting agent was controlled to be 0.9 mol / L, the concentration of chloride ion was 2.7 mol / L, and the concentration of hydrogen ion was 1.8 mol / L. 1g of CPU pins was added to each of the above non-aqua regia gold extracting agents at a solid-to-liquid ratio of 1:20g / mL. The reaction was stirred at room temperature for 3 hours, filtered through a 0.22μm filter, and 0.5mL of the filtrate was diluted and the gold content in the dilution was detected by ICP-OES.

[0048] Depend on Figure 4 It can be seen that when other conditions remain unchanged, only the type of weak acid in the non-aqua regia gold extraction agent is changed, the leaching rate of gold in CPU is above 95%, and there is little difference between different weak acids.

[0049] Example 4

[0050] Effect of different ferric nitrate concentrations in non-aqua regia gold extraction agents on the gold leaching rate from precious metal waste CPU

[0051] Add ferric nitrate and ferric chloride to 20 mL of acetic acid and stir magnetically until completely dissolved to obtain a non-aqua regia gold extraction agent. The chloride ion concentration, hydrogen ion concentration, and nitrate concentration in the non-aqua regia gold extraction agent are controlled to be 2.7 mol / L, 1.8 mol / L, and 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, and 2.5 mol / L, respectively. Add 1 g of CPU pins to each of the non-aqua regia gold extraction agents at a solid-to-liquid ratio of 1:20 g / mL. Stir and react at room temperature for 3 hours. Filter through a 0.22 μm filter, dilute 0.5 mL of the filtrate, and analyze the gold content in the dilution by ICP-OES.

[0052] Depend on Figure 5 It can be seen that when other conditions and reagents remain unchanged, only the amount of ferric nitrate in the non-aqua regia gold extraction agent is changed to make the nitrate concentration not less than 0.2 mol / L, the leaching rate of gold in CPU can reach more than 95%.

[0053] Example 5

[0054] Effect of different ferric chloride concentrations in non-aqua regia gold extraction agents on the gold leaching rate from precious metal-containing waste CPU

[0055] To 20 mL acetic acid, iron nitrate, ferric chloride was added, and after magnetic stirring until complete dissolution, a non-aqua regia gold extraction agent was obtained. The concentration of nitrate ions in the non-aqua regia gold extraction agent was controlled to be 0.9 mol / L, the concentration of hydrogen ions was 1.8 mol / L, and the concentration of chloride ions was 0.01 mol / L, 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.8 mol / L, 1.6 mol / L, 3.2 mol / L, and 6.4 mol / L, respectively. CPU pins 1 g were added to the above non-aqua regia gold extraction agent, and the solid-liquid ratio was 1:20 g / mL. The reaction was stirred at room temperature for 3 hours, filtered with a 0.22 μm filter, and 0.5 mL of the filtrate was diluted and detected by ICP-OES to detect the gold content in the diluted solution.

[0056] It can be seen that when other conditions and reagents remain unchanged, only the amount of ferric chloride in the non-aqua regia gold extraction agent is changed, and the leaching rate of gold in CPU is more than 95% when the concentration of chloride ions is not less than 0.4 mol / L. Figure 6 Example 6

[0057] Effect of different solid-liquid ratios in non-aqua regia gold extraction agent on gold leaching rate in CPU containing precious metal waste

[0058] To 20 mL acetic acid, iron nitrate, ferric chloride was added, and after magnetic stirring until complete dissolution, a non-aqua regia gold extraction agent was obtained. The concentration of nitrate ions in the non-aqua regia gold extraction agent was controlled to be 0.9 mol / L, the concentration of hydrogen ions was 1.8 mol / L, and the concentration of chloride ions was 2.7 mol / L. CPU pins 20 g, 10 g, 4 g, 2 g, 1 g, and 0.4 g were added to the above non-aqua regia gold extraction agent, and the solid-liquid ratio was 1:1 g / mL, 1:2 g / mL, 1:5 g / mL, 1:10 g / mL, 1:20 g / mL, and 1:50 g / mL, respectively. The reaction was stirred at room temperature for 3 hours, filtered with a 0.22 μm filter, and 0.5 mL of the filtrate was diluted and detected by ICP-OES to detect the gold content in the diluted solution.

[0059] It can be seen that when other conditions and reagents remain unchanged, only the solid-liquid ratio of the non-aqua regia gold extraction agent to the precious metal-containing waste is changed, and the leaching rate of gold in CPU is more than 95% when the solid-liquid ratio is not less than 1:10 g / mL.

[0060] Figure 7 Example 7

[0061] Effect of different types of precious metal-containing waste in non-aqua regia gold extraction agent on gold leaching rate

[0062] Effect of different types of precious metal-containing waste in non-aqua regia gold extraction agent on gold leaching rate

[0063] ​Add ferric nitrate and ferric chloride to 20 mL of acetic acid and stir magnetically until completely dissolved to obtain a non-aqua regia gold extraction agent. The concentration of nitrate in the non-aqua regia gold extraction agent is controlled to be 0.9 mol / L, the concentration of hydrogen ion is 1.8 mol / L, and the concentration of chloride ion is 2.7 mol / L. 1 g of CPU pins, mobile phone motherboard chip pins, computer motherboard components, integrated circuit chip pins, game console motherboard interfaces, gold-plated contacts of memory sticks, Gansu gold ore powder, Zhejiang gold ore powder, electronic scrap ore powder, automobile catalyst ore powder, and jewelry processing waste ore powder were added to the above non-aqua regia gold extraction agent at a solid-liquid ratio of 1:10 g / mL. Stir the reaction at room temperature for 3 hours, filter with a 0.22 μm filter, take 0.5 mL of the filtrate and dilute it, and then detect the gold content in the dilution by ICP-OES.

[0064] Depend on Figure 8 It can be seen that the leaching rate of gold from different types of precious metal-containing waste materials using non-aqua regia gold extraction agents can reach more than 95%.

[0065] Example 8

[0066] Leaching rate of gold from precious metal-containing waste CPU by non-aqua regia gold extraction agent at different reaction times

[0067] Add ferric nitrate and ferric chloride to 20 mL of acetic acid and stir magnetically until completely dissolved to obtain a non-aqua regia gold extraction agent. The concentration of nitrate in the non-aqua regia gold extraction agent is controlled to be 0.9 mol / L, the concentration of hydrogen ion is 1.8 mol / L, and the concentration of chloride ion is 2.7 mol / L. Add 1 g of CPU pin to the above non-aqua regia gold extraction agent with a solid-liquid ratio of 1:10 g / mL. Stir the reaction at room temperature. Samples are taken after 5, 10, 20, 40 minutes and 1, 2, 4, 6, 10, and 15 hours of reaction, respectively. Filter with a 0.22 μm filter, take 0.5 mL of the filtrate, dilute it, and detect the gold content in the dilution by ICP-OES.

[0068] Depend on Figure 9 It can be seen that when the reaction time exceeds 15 minutes, the leaching rate of gold from precious metal-containing waste CPU by non-aqua regia gold extraction agent can reach more than 95%.

[0069] Example 9

[0070] Leaching rate of gold from precious metal-containing waste CPU by non-aqua regia gold extraction agent at different reaction temperatures

[0071] Add ferric nitrate and ferric chloride to 20 mL of acetic acid and stir magnetically until completely dissolved to obtain a non-aqua regia gold extraction agent. The concentration of nitrate in the non-aqua regia gold extraction agent is controlled to be 0.9 mol / L, the concentration of hydrogen ion is 1.8 mol / L, and the concentration of chloride ion is 2.7 mol / L. Add 1 g of CPU pins to the above non-aqua regia gold extraction agent with a solid-liquid ratio of 1:10 g / mL. Stir and react at -20°C, -10°C, 0°C, 20°C, 40°C, 60°C, and 80°C for 3 hours, respectively. Filter with a 0.22 μm filter, take 0.5 mL of the filtrate, dilute it, and detect the gold content in the dilution by ICP-OES.

[0072] Depend on Figure 10 It can be seen that the leaching rate of gold from precious metal scrap CPU by non-aqua regia gold extracting agent remains basically unchanged at different reaction temperatures, and the leaching rate can reach more than 95%. Therefore, in order to reduce energy consumption, the reaction temperature of the present invention is selected to be room temperature.

[0073] Example 10

[0074] Extraction of gold from the whole CPU using non-aqua regia gold extractors

[0075] Add ferric nitrate and ferric chloride to 20 mL of acetic acid and stir magnetically until completely dissolved to obtain a non-aqua regia gold extraction agent. The concentration of nitrate in the non-aqua regia gold extraction agent is controlled to be 0.9 mol / L, the concentration of hydrogen ion is 1.8 mol / L, and the concentration of chloride ion is 2.7 mol / L. Take the whole CPU and add it to the above non-aqua regia gold extraction agent. After stirring and reacting at room temperature for 3 hours, the whole CPU is removed and filtered with a 0.22 μm filter. Take 0.5 mL of the filtrate and dilute it. The gold content in the dilution is detected by ICP-OES. The remaining filtrate is adjusted to pH 1.5-2.0 with concentrated hydrochloric acid and excess zinc powder is further added to the filtrate. After no precipitation is produced, excess hydrochloric acid is added to dissolve the unreacted zinc powder. After filtering and drying, sponge gold is obtained.

[0076] Depend on Figure 11 It can be seen that the non-aqua regia gold extraction agent has a significant effect on the extraction of gold from the entire CPU. Figure 11 After the CPU pins in a were treated with a non-aqua regia gold extracting agent, all the pins on the CPU board disappeared ( Figure 11 b), calculate its leaching rate, which can reach more than 95%, Figure 11 c It can be seen that the non-aqua regia gold extracting agent can leach all the metal parts of the CPU into the non-aqua regia gold extracting agent. Figure 11 d It can be seen that the sponge gold after zinc powder reduction is golden yellow gold. After being melted into liquid in a high-frequency heating furnace, it is dropped into water and cooled to obtain the molten gold in the upper left corner. Through elemental analysis, it can be seen that the molten gold obtained is high-purity gold element.

Claims

1. A non-aqua regia gold extraction agent for recovering precious metals from precious metal-containing waste materials, characterized by: The non-aqua regia gold extracting agent consists of nitrate, metal chloride and weak acid, and the concentration of nitrate in the non-aqua regia gold extracting agent is 0.2-2.0 mol / L, the concentration of chloride ion is 0.4-6.0 mol / L, and the concentration of hydrogen ion is 0.4-4.0 mol / L.

2. The non-aqua regia gold extraction agent for recovering precious metals from precious metal-containing waste according to claim 1, characterized in that: The concentration of nitrate in the non-aqua regia gold extraction agent is 0.4-1.5 mol / L, the concentration of chloride ion is 1.2-4.5 mol / L, and the concentration of hydrogen ion is 0.8-3.0 mol / L.

3. The non-aqua regia gold extraction agent for recovering precious metals from precious metal-containing waste materials according to claim 1, characterized in that: The concentration of nitrate in the non-aqua regia gold extraction agent is 0.6-1.0 mol / L, the concentration of chloride ion is 1.8-3.0 mol / L, and the concentration of hydrogen ion is 1.2-2.0 mol / L.

4. The non-aqua regia gold extraction agent for recovering precious metals from precious metal-containing waste materials according to any one of claims 1 to 3, characterized in that: The nitrate is selected from any one or more of lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, aluminum nitrate, ferrous nitrate, ferric nitrate, copper nitrate, zinc nitrate, silver nitrate, palladium nitrate, and bismuth nitrate.

5. The non-aqua regia gold extraction agent for recovering precious metals from precious metal-containing waste materials according to any one of claims 1 to 3, characterized in that: The metal chloride is selected from any one or more of sodium chloride, potassium chloride, lithium chloride, magnesium chloride, calcium chloride, aluminum chloride, ferric chloride, ferrous chloride, cupric chloride, zinc chloride, manganese chloride, nickel chloride, silver chloride, palladium chloride, and platinum chloride.

6. The non-aqua regia gold extraction agent for recovering precious metals from precious metal-containing waste materials according to any one of claims 1 to 3, characterized in that: The weak acid is selected from any one or more of carbonic acid, silicic acid, boric acid, phosphoric acid, sulfurous acid, hydrosulfuric acid, hypochlorous acid, acetic acid, propionic acid, citric acid, lactic acid, malic acid, tartaric acid, and amino acids.

7. A method for recovering precious metals from precious metal-containing waste, characterized in that: The precious metal waste is classified according to its metal composition and grade, and the classified waste is added to the above-mentioned non-aqua regia gold extraction agent. Non-aqua regia gold extraction agents containing different concentrations of nitrate, chloride and hydrogen ions are prepared for different metal elements. The precious metals are oxidized and leached by stirring at room temperature for 1 to 10 hours, and then the precious metal ions are reduced to precious metal elements to obtain precious metal products.

8. The method for recovering precious metals from precious metal-containing waste according to claim 7, wherein: The solid-liquid ratio of the precious metal-containing waste material to the non-aqua regia gold extraction agent is 1:10 to 1:100 g / mL.

9. The method for recovering precious metals from precious metal-containing waste according to claim 7, wherein: The solid-liquid ratio of the precious metal-containing waste material to the non-aqua regia gold extraction agent is 1:20 to 1:80 g / mL.

10. The method for recovering precious metals from precious metal-containing waste according to claim 7, wherein: The waste materials containing precious metals include electronic waste and mineral powder; The electronic waste includes any one or more of computer motherboards, CPUs, gold-plated contacts of memory sticks, memory stick pins, mobile phone motherboard chip pins, gold-plated contacts of router network ports, digital camera lens module contacts, game console motherboard interfaces, industrial control board connectors, gold-plated parts of medical instrument electrodes, integrated circuit chip pins, gold-plated contacts of relays, and platinum-rhodium materials in sensors; The mineral powder includes any one or more of gold mineral powder, silver mineral powder, platinum group metal mineral powder, placer gold mineral powder, electronic scrap mineral powder, automobile catalyst mineral powder, chemical waste mineral powder, electroplating waste mineral powder, jewelry processing waste mineral powder, and mineral powder containing iridium and osmium rare precious metals.

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