Metal leaching agent containing ionic liquid and metal leaching method

Abstract

The present invention discloses a metal leaching agent containing ionic liquid and a metal leaching method. The metal leaching agent containing ionic liquid is formed by mixing nitroxide free radical compounds, anhydrous aluminum chloride, water and ionic liquid in proportion; the ionic liquid is at least one of 1-butyl-2,3-dimethylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium chloride, 1-butyl-3-dimethylimidazolium bromide, 1-propyl-3-dimethylimidazolium bromide and dodecyltrimethylammonium bromide; the nitroxide free radical compound is at least one of nitroxide free radical piperidinol and 2,2,6,6-tetramethylpiperidine-1-oxygen free radical. The present invention provides a metal leaching method based on the metal leaching agent containing ionic liquid. The metal leaching agent provided by the present invention has good oxidation and metal coordination capabilities, can leach precious metals such as gold, palladium and platinum, and has a fast gold leaching speed and a high extraction rate.

Description

Technical Field

[0001] The invention relates to a metal leaching agent containing ionic liquid and a metal leaching method based on the metal leaching agent. Background Art

[0002] Precious metals are scarce strategic metals, widely used in gold jewelry, currency reserves and high-tech industries, and have irreplaceable significance in the national economy and social development. Precious metals have excellent properties such as good stability, strong ductility, good catalytic activity, small size, corrosion resistance and high temperature resistance, and occupy an extremely important position in many fields such as national economy and industrial production. However, precious metals are scarce in nature and often coexist with other metals. Therefore, it is our goal to continuously explore the separation and recovery methods of precious metals that meet the requirements of the times and reduce the pollution to the natural environment and the consumption of natural resources. According to the data report of the US Geological Survey, the amount of high-quality gold resources that have been discovered and utilized in the world is about 890 million tons, of which about 1 / 3 of the high-quality gold resources are difficult to process. With the reduction of these high-quality gold resources, this proportion is still increasing. Due to the low technical level of my country's gold industry, gold-containing materials such as antimony, lead, zinc, sulfur, arsenic and carbon have not been well developed and utilized, which has become an important factor restricting the development of my country's gold industry.

[0003] At present, the pyrometallurgical method of gold extraction from gold-containing materials mainly uses base metals such as copper, iron, cobalt, and nickel to melt and capture precious metals such as gold, silver, and platinum at high temperatures. The loss rate of precious metals recovered by pyrometallurgy is small, the recovery rate is high, the applicability is wide, and the process is mature. Although the pyrometallurgical process is simple, it has high energy consumption requirements, large pollution discharge, and high costs for processing gold mines. There are still problems in the large-scale implementation of pyrometallurgical gold extraction. Therefore, hydrometallurgical gold extraction has more advantages than pyrometallurgical gold extraction.

[0004] Hydrometallurgy is a process of chemically extracting and separating various metal elements contained in metallurgical raw material solutions directly through various chemical reaction methods. The main methods reported and applied at present are thiourea method, halogen metal and other compound method, cyanidation method, etc. Iodination method is used for gold leaching. This treatment method has a higher leaching rate for gold ore than the wet method, but it consumes more iodine. Alkaline thiourea method for gold leaching. This treatment method may have problems such as low gold leaching rate, low leaching efficiency, unstable thiourea and high price. Biological gold leaching can effectively reduce energy consumption and biological leaching pollution while leaching gold, but there are problems such as low efficiency. Halide gold leaching. Studies have shown that high temperature and low liquid-solid ratio are conducive to bromination leaching. Under the best conditions, the gold leaching rate is about 70%. The halogenation method has low toxicity, short processing time and good leaching effect, but it has disadvantages such as high production cost and high equipment requirements. Cyanidation gold leaching is the main method for modern gold extraction. The gold produced by this process accounts for about 70% of the total national output. The cyanidation process for gold extraction has a history of 100 years. Due to its low cost, outstanding effect and mature process, it is still the main method for gold leaching production. In recent years, the country has continuously raised its requirements for environmental protection, which is a new challenge for ore companies. The cyanidation method has the advantages of fast leaching speed and low price, but the gold leaching agent cyanide is a highly toxic substance. During transportation and use, it not only pollutes the environment but also endangers the lives of humans and animals. In the new version of the "National List of Hazardous Wastes" issued by the Ministry of Environmental Protection, the National Development and Reform Commission and the Ministry of Public Security, "cyanide tailings produced in the process of gold beneficiation using cyanide" are included in the list of hazardous wastes. Therefore, it is necessary to study a more efficient, green and economical method for recovering precious metals.

[0005] Ionic liquids are molten salt systems that are liquid at room temperature or near room temperature. They are composed of anions and cations, and have a vapor pressure of almost zero. They are a type of environmentally friendly reagent that can be used as solvents for many organics, polymer materials, and inorganic substances, and are considered to be a good substitute for traditional organic solvents. Compared with traditional reagents, ionic liquids have low volatility and are non-flammable, which makes them relatively safe and environmentally friendly. They are considered to be suitable substitutes for ordinary organic solvents, which also makes them widely used in the extraction of precious metals.

[0006] Ionic liquids have properties such as acidity, alkalinity, and solubility, and their properties are determined by the types of anions and cations. By designing and modifying different anions and cations, more than 1 trillion ionic liquids can be synthesized in theory. People can design, synthesize, and screen ionic liquids that meet actual working environments and conditions according to specific needs. In complex metal recovery environments, ionic liquids have the advantages of flexible application and strong adaptability. When ionic liquids are used to extract metal ions from water, hydrophobic ionic liquids are required to form complexes to transfer metal ions to the ionic liquid phase.

[0007] Although ionic liquids have been intensively studied and widely used in metal ion extraction, there is not much research on the extraction of elemental precious metals by ionic liquids. Summary of the invention

[0008] The primary purpose of the present invention is to provide a metal leaching agent containing ionic liquid, which has good oxidation and metal coordination capabilities, can leach precious metals such as gold, palladium, platinum, etc., has a fast gold leaching speed and a high extraction rate.

[0009] The secondary purpose of the present invention is to provide a metal leaching method based on the above metal leaching agent, which is highly efficient and environmentally friendly.

[0010] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0011] In a first aspect, the present invention provides a metal leaching agent containing an ionic liquid, which is mixed by a nitroxide free radical compound, anhydrous aluminum chloride, water and an ionic liquid in a mass ratio of 0.8-1.2:2.5-4.5:8-16:6; the ionic liquid is at least one of 1-butyl-2,3-dimethylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium chloride, 1-butyl-3-dimethylimidazolium bromide, 1-propyl-3-dimethylimidazolium bromide and dodecyltrimethylammonium bromide; the nitroxide free radical compound is at least one of nitroxide free radical piperidinol and 2,2,6,6-tetramethylpiperidin-1-oxyl free radical.

[0012] The metal leaching agent of the present invention only needs to be prepared by uniformly mixing the components. The nitroxyl free radical piperidinol is an orange-yellow flaky crystalline substance.

[0013] Preferably, the ionic liquid is at least one of 1-butyl-2,3-dimethylimidazolium bromide and 1-butyl-2,3-dimethylimidazolium chloride, and most preferably 1-butyl-2,3-dimethylimidazolium bromide.

[0014] Preferably, the nitroxide free radical compound is the nitroxide free radical piperidinol.

[0015] Preferably, the mass ratio of the nitroxide free radical to water, ionic liquid and anhydrous aluminum chloride is 1-1.2:10-14:6:3-3.8, most preferably 1:12:6:3.4.

[0016] The nitroxide free radical piperidinol and 2,2,6,6-tetramethylpiperidin-1-oxyl free radical used in the present invention can be prepared by those skilled in the art according to methods reported in the literature.

[0017] The present invention further provides a metal leaching method based on the metal leaching agent containing ionic liquid, the metal leaching method comprising:

[0018] 1) obtaining the metal leaching agent containing the ionic liquid;

[0019] 2) Add the sample containing precious metals into the metal leaching agent obtained in step 1) and stir thoroughly to leach the precious metals.

[0020] Preferably, the precious metal is at least one of gold, palladium and platinum.

[0021] Preferably, the sample containing precious metals is precious metal powder or gold ore particles.

[0022] Preferably, the mass ratio of the ionic liquid contained in the metal leaching agent containing the ionic liquid to the precious metal in the sample containing the precious metal is 600-2000:1.

[0023] Preferably, in step 2), the leaching temperature is controlled to be 40-80°C, more preferably 60-80°C, most preferably 60°C. Within this temperature range, the metal leaching system has excellent leaching efficiency.

[0024] Compared with traditional metal leaching agents, the present invention has the following advantages:

[0025] 1. The ionic liquid system used in the metal leaching agent of the present invention is an environmentally friendly compound, which has almost no harm to the environment and people during the production process, meets the requirements of building an environmentally friendly society at present, and is a sustainable development system;

[0026] 2. The metal leaching agent system of the present invention has good oxidizability and coordination ability, can leach precious metals such as gold and palladium, has a fast leaching speed and a high extraction rate, and does not require an external oxidant when used;

[0027] 3. The metal leaching agent of the present invention can be used for metallurgical treatment at low temperature, with mild conditions and low overall energy consumption. DETAILED DESCRIPTION

[0028] The present invention is described below with specific examples. It is necessary to point out that the embodiments are only used to further illustrate the present invention, but cannot be understood as limiting the scope of protection of the present invention, and the present invention is not limited thereto in any way. Personnel skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention.

[0029] Example 1

[0030] The mass ratio of nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide is 1:12:3.4:6. Take 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water and mix them evenly at room temperature to obtain 9.5ml of solution. Add 0.0042g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0031] The Au concentration of the solution was measured by atomic absorption spectrometer to be 4.41 ug / ml, and the solubility was calculated to be 99.75%.

[0032] Example 2

[0033] The mass ratio of nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-3-methylimidazolium bromide is 1:12:2.6:6. Take 3g of 1-butyl-3-methylimidazolium bromide, 0.5g of nitroxyl piperidinol, 1.8g of anhydrous aluminum chloride and 6.0ml of water and mix them evenly at room temperature to obtain 9.5ml of solution. Add 0.0045g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0034] The Au concentration of the solution was measured by atomic absorption spectrometer to be 3.80 ug / ml, and the calculated dissolution rate was 75.45%.

[0035] Example 3

[0036] The nitroxide piperidinol, water, anhydrous aluminum chloride and 1-propyl-3-methylimidazolium bromide are mixed in a mass ratio of 1:12:3.8:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxide piperidinol, 1.9g of anhydrous aluminum chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.6ml of solution. 0.0043g of gold powder is added and heated at 60℃ with stirring for 60 minutes.

[0037] The Au concentration of the solution was measured by atomic absorption spectrometer to be 3.87 ug / ml, and the dissolution rate was calculated to be 81.36%.

[0038] Example 4

[0039] The nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium chloride are mixed in a mass ratio of 1:12:4.2:6. 3g of 1-butyl-2,3-dimethylimidazolium chloride, 0.5g of nitroxyl piperidinol, 2.1g of anhydrous aluminum chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.7ml of solution. 0.0041g of gold powder is added and heated at 60°C with stirring for 9 hours.

[0040] The Au concentration of the solution was determined by atomic absorption spectrometer to be 4.19ug / ml, and the calculated dissolution rate was 99.12%. When the gold powder was heated and stirred at 60°C for 60 minutes, the calculated dissolution rate was about 25%.

[0041] Example 5

[0042] The nitroxyl piperidinol, water, anhydrous aluminum chloride and dodecyl trimethyl ammonium bromide are prepared in a mass ratio of 1:12:2.6:6. 3 g of dodecyl trimethyl ammonium bromide, 0.5 g of nitroxyl piperidinol, 1.3 g of anhydrous aluminum chloride and 6.0 ml of water are mixed evenly at room temperature to obtain 9.3 ml of solution. 0.0042 g of gold powder is added and heated at 60°C with stirring for 9 hours.

[0043] The Au concentration of the solution was measured by atomic absorption spectrometer to be 3.63ug / ml, and the calculated dissolution rate was 80.37%. When the gold powder was heated and stirred at 60°C for 60 minutes, the calculated dissolution rate was about 72%.

[0044] Example 6

[0045] 2,2,6,6-Tetramethylpiperidin-1-oxyl free radical, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide in a mass ratio of 1:12:3.4:6. Take 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of 2,2,6,6-tetramethylpiperidin-1-oxyl free radical, 1.7g of anhydrous aluminum chloride and 6.0ml of water and mix them evenly at room temperature to obtain 9.5ml of solution. Add 0.0045g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0046] The Au concentration of the solution was measured by atomic absorption spectrometer to be 4.47 ug / ml, and the calculated dissolution rate was 94.36%.

[0047] Example 7

[0048] The nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 0.8:12:3.4:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.4g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.5ml of solution. 0.0045g of gold powder is added and heated at 60°C with stirring for 60 minutes.

[0049] The Au concentration of the solution was measured by atomic absorption spectrometer to be 4.17 ug / ml, and the calculated dissolution rate was 88.03%.

[0050] Example 8

[0051] The mass ratio of nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide is 1.2:12:3.4:6. Take 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.6g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water and mix them evenly at room temperature to obtain 9.5ml of solution. Add 0.0045g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0052] The Au concentration of the solution was measured by atomic absorption spectrometer to be 4.73 ug / ml, and the dissolution rate was calculated to be 99.85%.

[0053] Example 9

[0054] The nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 1:12:3.4:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.5ml of solution. 0.0044g of palladium powder is added and heated at 60°C with stirring for 60 minutes.

[0055] The Pd concentration of the solution was measured by atomic absorption spectrometer to be 4.63 ug / ml, and the solubility was calculated to be 99.96%.

[0056] Example 10

[0057] The nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 1:12:3.4:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.5ml of solution. 0.0015g of platinum powder is added and heated at 60°C with stirring for 60 minutes.

[0058] The Pt concentration of the solution was measured by atomic absorption spectrometer and was 1.57 ug / ml. The calculated dissolution rate was 99.43%.

[0059] Embodiment 11

[0060] The nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 1.0:12:3.4:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.5ml of solution. 0.0042g of gold powder is added and heated at 80°C with stirring for 60 minutes.

[0061] The Au concentration of the solution was measured by atomic absorption spectrometer and was 3.79 ug / ml. The calculated dissolution rate was 85.72%.

[0062] Example 12

[0063] The mass ratio of nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide is 1.2:12:3.4:6. Take 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.6g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 4.0ml of water and mix them evenly at room temperature to obtain 7.5ml of solution. Add 0.0046g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0064] The Au concentration of the solution was measured by atomic absorption spectrometer to be 5.44 ug / ml, and the calculated dissolution rate was 88.69%.

[0065] Comparative Example 1

[0066] The ratio of nitroxyl piperidinol, water and anhydrous aluminum chloride is 1:12:3.4. Take 0.5g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water and mix them evenly at room temperature to obtain 7.0ml of solution. Add 0.0048g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0067] The Au concentration of the solution was measured by atomic absorption spectrometer and was 0.023 ug / ml, and the calculated dissolution rate was 0.33%.

[0068] Comparative Example 2

[0069] The nitroxyl piperidinol, water and 1-butyl-2,3-dimethylimidazolium bromide are prepared in a mass ratio of 1:12:6. 3 g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5 g of nitroxyl piperidinol and 6.0 ml of water are mixed evenly at room temperature to obtain 8.6 ml of solution. 0.0040 g of gold powder is added and heated at 60°C with stirring for 60 minutes.

[0070] The Au concentration of the solution was measured by atomic absorption spectrometer to be 0.00 ug / ml, and the calculated dissolution rate was 0.00%.

[0071] Comparative Example 3

[0072] Water, anhydrous aluminum chloride, 1-butyl-2,3-dimethylimidazolium bromide in a mass ratio of 12:3.4:6. Take 3g of 1-butyl-2,3-dimethylimidazolium bromide, 1.7g of anhydrous aluminum chloride, and 6.0ml of water and mix them evenly at room temperature to obtain 9.3ml of solution. Add 0.0040g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0073] The Au concentration of the solution was measured by atomic absorption spectrometer to be 0.00 ug / ml, and the calculated dissolution rate was 0.00%.

[0074] Comparative Example 4

[0075] The nitroxyl piperidinol, water, sodium chloride and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 1:12:1.5:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxyl piperidinol, 0.75g of sodium chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.0ml of solution. 0.0043g of gold powder is added and heated at 60°C with stirring for 9 hours.

[0076] The Au concentration of the solution was measured by atomic absorption spectrometer to be 0.065 ug / ml, and the calculated dissolution rate was 1.36%.

[0077] Comparative Example 5

[0078] The nitroxyl piperidinol, water, potassium chloride and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 1:12:1.8:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxyl piperidinol, 0.9g of potassium chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.1ml of solution. 0.0046g of gold powder is added and heated at 60°C with stirring for 9 hours.

[0079] The Au concentration of the solution was measured by atomic absorption spectrometer to be 0.093 ug / ml, and the dissolution rate was calculated to be 1.83%.

[0080] Comparative Example 6

[0081] The nitroxyl piperidinol, water, potassium bromide and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 1:12:3:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of nitroxyl piperidinol, 1.5g of potassium bromide and 6.0ml of water are mixed evenly at room temperature to obtain 9.4ml of solution. 0.0042g of gold powder is added and heated at 60°C with stirring for 9 hours.

[0082] The Au concentration of the solution was measured by atomic absorption spectrometer to be 0.102 ug / ml, and the calculated dissolution rate was 2.28%.

[0083] Comparative Example 7

[0084] 4-Amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide in a mass ratio of 1:12:3.4:6. Take 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, 1.7g of anhydrous aluminum chloride and 6.0ml of water and mix them evenly at room temperature to obtain 9.5ml of solution. Add 0.0044g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0085] The Au concentration of the solution was measured by atomic absorption spectrometer and was 1.411 ug / ml, and the dissolution rate was calculated to be 30.44%.

[0086] Comparative Example 8

[0087] 4-oxyl-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide in a mass ratio of 1:12:3.4:6. Take 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.5g of 4-oxyl-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, 1.7g of anhydrous aluminum chloride and 6.0ml of water and mix them evenly at room temperature to obtain 9.5ml of solution. Add 0.0045g of gold powder and heat at 60℃ with stirring for 60 minutes.

[0088] The Au concentration of the solution was measured by atomic absorption spectrometer to be 0.099 ug / ml, and the calculated dissolution rate was 2.09%.

[0089] Comparative Example 9

[0090] The nitroxyl piperidinol, water, anhydrous aluminum chloride and 1-butyl-2,3-dimethylimidazolium bromide are mixed in a mass ratio of 0.6:12:3.4:6. 3g of 1-butyl-2,3-dimethylimidazolium bromide, 0.3g of nitroxyl piperidinol, 1.7g of anhydrous aluminum chloride and 6.0ml of water are mixed evenly at room temperature to obtain 9.4ml of solution. 0.0044g of gold powder is added and heated at 60°C with stirring for 60 minutes.

[0091] The Au concentration of the solution was measured by atomic absorption spectrometer and was 3.13 ug / ml. The calculated dissolution rate was 66.86%.

[0092] Comparative Example 10

[0093] The nitroxyl piperidinol, water, anhydrous aluminum chloride and N-butylpyridinium tetrafluoroborate are prepared in a mass ratio of 1:12:2.6:6. 3 g of N-butylpyridinium tetrafluoroborate, 0.5 g of nitroxyl piperidinol, 1.3 g of anhydrous aluminum chloride and 6.0 ml of water are mixed evenly at room temperature to obtain 9.3 ml of solution. 0.0045 g of gold powder is added and heated at 60°C with stirring for 9 hours.

[0094] The Au concentration of the solution was measured by atomic absorption spectrometer and was 3.01 ug / ml. The calculated dissolution rate was 62.20%.

Claims

1. A metal leaching agent containing an ionic liquid, characterized in that: The metal leaching agent containing ionic liquid is prepared by mixing nitroxide free radical compound, anhydrous aluminum chloride, water and ionic liquid in a mass ratio of 0.8-1.2:2.5-4.5:8-16:6; the ionic liquid is at least one of 1-butyl-2,3-dimethylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium chloride, 1-butyl-3-dimethylimidazolium bromide, 1-propyl-3-dimethylimidazolium bromide and dodecyltrimethylammonium bromide; the nitroxide free radical compound is at least one of nitroxide free radical piperidinol and 2,2,6,6-tetramethylpiperidin-1-oxyl free radical.

2. The metal leaching agent containing ionic liquid according to claim 1, characterized in that: The mass ratio of the nitroxide free radical compound, anhydrous aluminum chloride, water and ionic liquid is 1-1.2:3-3.8:10-14:

6.

3. The metal leaching agent containing ionic liquid according to claim 1, characterized in that: The mass ratio of the nitroxide free radical compound, anhydrous aluminum chloride, water and ionic liquid is 1:3.4:12:

6.

4. A metal leaching method based on a metal leaching agent containing an ionic liquid according to any one of claims 1 to 3, characterized in that The metal leaching method comprises: 1) obtaining a metal leaching agent containing an ionic liquid according to any one of claims 1 to 3; 2) Add the sample containing precious metals into the metal leaching agent obtained in step 1) and stir thoroughly to leach the precious metals.

5. The metal leaching method according to claim 4, characterized in that: The noble metal is at least one of gold, palladium and platinum.

6. The metal leaching method according to claim 4, characterized in that: The sample containing precious metals is precious metal powder or gold ore particles.

7. The metal leaching method according to claim 4, characterized in that: The mass ratio of the ionic liquid contained in the metal leaching agent containing the ionic liquid to the precious metal in the sample containing the precious metal is 600-2000:

1.

8. The metal leaching method according to claim 4, characterized in that: In step 2), the leaching temperature is controlled to be 40-80°C.

9. The metal leaching method according to claim 4, characterized in that: In step 2), the leaching temperature is controlled at 60-80°C.

10. The metal leaching method according to claim 4, characterized in that: In step 2), the leaching temperature is controlled to be 60°C.