Method for selectively leaching and extracting noble metals from organic solvents

Abstract

To provide methods for leaching and extraction of precious metals.SOLUTION: For example, the present application relates to methods of leaching gold, palladium and / or platinum from a substance comprising gold, palladium and / or platinum (such as a gold-containing ore or a platinum group metal (PGM) concentrate) using an organic solvent that is water-miscible or partially water-miscible.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority from concurrently pending U.S. Provisional Patent Application No. 62 / 150,513 (filed April 21, 2015) and U.S. Provisional Patent Application No. 62 / 152,066 (filed April 24, 2015), the entirety of which is incorporated herein by reference.

[0002] field This application relates to a method for leaching and extracting precious metals. For example, this application relates to a method for leaching gold, palladium, and / or platinum from a substance containing such precious metals (such as gold-containing ore or platinum group metal (PGM) concentrate) using a water-miscible or partially water-miscible organic solvent. [Background technology]

[0003] background Gold is an element that belongs to the same group as silver and copper in the periodic table. Gold is usually found in combination with these metals in ore. The average concentrations of copper and silver in the Earth's crust are 50 and 0.07 ppm (parts per million), respectively, while the average concentration of gold is just 0.005 ppm. 1 .

[0004] Gold deposits with concentrations of 0.5 ppm or higher are considered economically recoverable. Due to its limited resources, gold recovery from secondary sources, as well as from ore, has become increasingly important in recent decades. The annual global production of gold from gold mining exceeds 2,500 tons. 2 In addition, approximately 900 tons of secondary gold are recovered from a variety of resources, including, but not limited to, anode slime and jewelry, dental and electronic scrap. 3 .

[0005] The most commonly used process for recovering gold from ore is a process known as leaching, which extracts gold(0) from water-soluble Au(CN)2. - This involves the use of highly toxic inorganic cyanides (e.g., NaCN, KCN) to convert them into coordination complexes. An example of a known process 10 for gold recovery using cyanide leaching is shown in Figure 1. In process 10, low-grade ore 12 is crushed and polished 14, and then leached in a basic solution of NaCN for 16 to 48 hours depending on the ore type 16. Due to several environmental disasters in various gold mines around the world, gold leaching by cyanide has been banned in many countries. 4 As a result, numerous attempts have been made to find alternatives to cyanide, and various leaching agents have been studied and proposed. 5、6 .

[0006] Generally, after dissolving gold in a cyanide solution, gold is recovered by activated carbon adsorption (for example, step 18 in process 10 in Figure 1, where, for example, 0.1 to 1 kg of activated carbon is used per ton of ore) or by a zinc cementation process. The activated carbon adsorption process is quite common. 7、8 For example, 1 ton of activated carbon can adsorb 4 to 8 kg of gold over 4 to 8 hours in 4 to 8 steps.

[0007] As shown in Figure 1, after the carbon adsorption step 18, the packed activated carbon is washed with a low concentration of HCl 20 to remove adsorbed impurities such as Zn, Ca, Fe, Cu, and Ag, and then gold desorption (elution) 22 is performed, for example, by using a 1% NaOH and 0.1-0.2% NaCN solution at a high temperature (e.g., 110°C) for 36-72 hours. Pure gold 24 can be obtained, for example, by electrolysis or reduction. The total process time for gold recovery using a process such as process 10 shown in Figure 1 is 46-110 hours.

[0008] Processes for gold recovery using activated carbon may have several drawbacks including, but not limited to, low selectivity, very long procedures, loss of gold product, high temperature requirements, and further consumption of cyanide to desorb gold from the activated carbon, all of which can result in additional costs during the gold recovery process. 9 .

[0009] Although significant attempts have been made to replace cyanide, the reported leaching reagents have not been used in the industrialization of gold products due to drawbacks such as (i) high reagent consumption, (ii) complex chemistry, (iii) lack of industrial techniques for recovering gold from the resulting solutions, and (iv) low gold recovery rates compared to cyanide. Drawbacks such as toxicity, cost, long reaction times, and poor selectivity are also associated with known systems. For this reason, it may be desirable to develop more effective leaching agents with higher efficiency and / or lower toxicity from both environmental and economic perspectives.

[0010] Cyanide leaching For over a century, cyanidation has remained a powerful process for extracting and recovering gold from ores. Metallic gold can dissolve in an alkaline solution of potassium cyanide or sodium cyanide in the presence of dissolved molecular oxygen (Reaction 1). [Chemical formula]

[0011] Under neutral or acidic conditions, more than 99% of the cyanide exists as highly toxic HCN gas. By increasing the pH, the HCN gas is converted to free cyanide ions, and as a result, at a pH of 9.3, CN - and HCN are in equilibrium and each exists at 50%. At a pH of 11, more than 99% of the cyanide remains in the solution as CN - remaining in the solution 10 . Free cyanide ions react with gold in aqueous solution, Au(CN)2 -It is a very strong ligand that can form extremely stable complexes. At stoichiometric ratios, the dissolution of gold in alkaline cyanide solutions is slow, but by increasing the cyanide concentration, the leaching rate increases until it reaches a maximum value (0.075 w / w% KCN or 0.06% NaCN), after which the dissolution rate remains constant. 11 .

[0012] Before cyanide treatment, gold ore is typically crushed and polished to reduce the size of the ore particles to 75 micrometers or less, providing a larger contact surface area between the gold and the leaching solution. Depending on the type of ore, the amount of cyanide consumed varies from approximately 0.25 to 2 kg per ton of ore, and the dissolution rate of gold in cyanide takes 16 to 48 hours. 11 As the fire resistance of gold ore increases, the amount of cyanide consumed also increases. Heat-resistant gold ore is gold-containing ore that is resistant to recovery by direct cyanide extraction. Other minerals and metals also dissolve in alkaline cyanide solutions, and they typically consume cyanide and oxygen, thus reducing the overall efficiency of gold leaching.

[0013] For example, copper minerals such as chalcocite (Cu2S) and cuprite (Cu2O) have various cyanide complexes, such as CuCN and Cu(CN)2 - Cu(CN)3 2- , and Cu(CN)4 3- Iron sulfides such as pyrrhotite (Fe7S8), pyrite (FeS2), and arsenopyrite (FeAsS) can form extremely stable Fe(CN)6. 4- and Fe(CN)6 3- Forming 12 In addition, most sulfide minerals have a detrimental effect on gold leaching because they can deactivate the gold surface and consume cyanide and oxygen. However, some other minerals, such as galena (PbS), can improve the rate of gold leaching by preventing the formation of an inactivating layer on the gold surface. 13 .

[0014] Although cyanide remains the primary leaching agent for gold recovery in mining, it has several drawbacks, including, but not limited to, high toxicity, a slow leaching reaction rate, and poor gold extraction from heat-resistant ores. Therefore, considerable effort has been made to find alternatives to cyanide.

[0015] Gold recovery from cyanide solution There are several techniques for recovering gold from cyanide leaching solutions, including the much more common carbon adsorption, zinc cementation, and solvent extraction by carbon adsorption. 14、15 In the carbon adsorption technique, after gold is leached in a cyanide solution, AuCN2 is removed from other metals and impurities. - Activated carbon is applied for selective gold adsorption to separate Au(CN)2 from cyanide solution. - In the 4-8 step process, which takes 4-8 hours to completely adsorb the complex, typically 0.1-1 kg of activated carbon is applied per ton of ore. The packed activated carbon is usually washed with a low-concentration HCl solution to remove other impurities such as Fe, Cu, Zn, Ca, and Ag. Subsequently, the dicyanogold(I) complex is removed from the activated carbon in the elution step by washing the packed activated carbon with a fresh basic sodium cyanide solution at 110°C for 36-72 hours. 10、16 Detachable Au(CN)2 - The complex is ultimately reduced to elemental gold by electrolysis or reduction.

[0016] The activated carbon method has several drawbacks, though not limited to them, including low selectivity, very long procedures, loss of some gold products, and high-temperature requirements. 17 .

[0017] Cyanide substitutes Due to the high toxicity and environmental concerns of cyanide, there is a need to find useful alternatives. In recent years, several cyanide alternatives have been reported to efficiently leach gold ore. Some of the reported useful leaching reagents are thiosulfates, thiocyanites, thioureas, and chlorides combined with oxidizing agents such as HNO3, H2O2, and hypochlorites.

[0018] Thiosulfate leaching Thiosulfates are the most studied alternatives to cyanides. Gold can leach in alkaline aqueous solutions (pH = 9.5-10.5) of thiosulfates in the presence of oxidizing agents such as O2 and copper(II) ions. The rate of gold dissolution is slower in the absence of copper(II) ions. 18 Ammonia is typically used to accelerate the rate of gold leaching in this medium. Cu is used to stabilize the intermediate oxidation products of gold. 2+ This reduces the rate of thiosulfate oxidation, prevents the formation of insoluble components such as sulfides on the gold surface, and prevents Cu(NH3)4 from forming during the leaching process. 2+ By forming a high concentration of Cu 2+ Maintaining it has an effective role. 19、20 Oxygen is Cu(NH3)2 + Cu(NH3)4 2+ It has a dual role through oxidation to or direct oxidation of the gold surface. The overall equilibrium equation for the dissolution of gold in a thiosulfate medium is shown in the following reaction. 21 (2). [ka]

[0019] Compared to the cyanide process, thiosulfate leaching offers several advantages, including a faster leaching reaction rate, lower toxicity, and higher gold recovery rates, although these are not limited to certain heat-resistant gold ores. 22、23However, thiosulfate leaching has several major drawbacks, though not limited to complex chemistry, ammonia toxicity, the ineffectiveness of activated carbon for desorption of leached gold, and high consumption of thiosulfate.

[0020] For example, copper(II) itself consumes thiosulfate, resulting in high consumption of both thiosulfate and copper, and the resulting tetrathionate (S4O6) 2- ) decomposes into elemental sulfur, forming a sulfide, for example, CuS, which increases gold passivation during the leaching process (reaction 3). 24、25 . [ka]

[0021] Thiourea Thiourea is another well-studied leaching agent that can dissolve gold in an acidic medium based on the following reaction (4). 26 . [ka]

[0022] Various oxidizing agents, including but not limited to hydrogen peroxide, sodium peroxide, oxygen, ozone, and ferric ions, can be used in combination with thiourea to dissolve gold. Among these oxidizing agents, ferric ions in sulfuric acid solution are particularly useful (Reaction 5). 27 . [ka]

[0023] However, thiourea is not stable in acidic media in the presence of ferric ions and decomposes into sulfur and cyanamide. 28 The addition of reducing agents such as SO2 reduces the consumption of thiourea by preventing its oxidation. 29The reaction rate of gold leaching in thiourea solution is not limited, but is much faster than the cyanide process due to the use of non-gaseous oxidants such as hydrogen peroxide and ferric sulfate instead of oxygen used in the cyanide process. 30 However, gold recovery using cyanide and the resulting reagent consumption are more economical than using thiourea. 31 .

[0024] Complexation with base metals such as copper accelerates the consumption of thiourea and reduces the rate of gold leaching. Thermal degradation, ferric sulfate, and oxidation by air are other reasons for the high consumption of thiourea. 32 The commercial use of thiourea has been hindered by its high consumption and the lack of applicable industrial techniques for recovering gold from its solutions. Despite having lower toxicity compared to cyanide, thiourea is suspected of being a carcinogen and is handled with caution. 33 .

[0025] Chloride solution containing an oxidizing agent Concentrated oxidizers combined with strong oxidizing agents are known, for example, as strong leaching agents for extracting precious metals from scrap and secondary resources. 34 A hot solution of concentrated HCl mixed with concentrated HNO3 (known as aqua regia) or hydrogen peroxide can dissolve gold by the following chemical reaction (see reactions 6 and 7), and stable AuCl4 - This leads to the formation of complexes. 35 . [ka] [ka]

[0026] Aside from these oxidants, chlorine gas can also be used to form the same metal type. 36Chlorine was used to dissolve gold from ore and concentrates throughout the latter half of the 19th century until it was gradually replaced by the more economical alkaline cyanide leaching. However, in all cases, the dissolution rate is faster compared to cyanide due to the high concentration of HCl, and all of these solutions are extremely corrosive and toxic, making the consumption of chlorine uneconomical in the case of gold ore processing. 37 .

[0027] Chloride / Hypochlorite Chloride / hypochlorite solutions are recognized as an alternative leaching agent to cyanide, capable of dissolving gold over a wide range of pH values. 38 Depending on the pH of the solution, three different oxidizing species can be formed in the hypochlorite solution. When the pH is above 7.5, hypochlorite ions (OCl) are formed. - ) is the dominant species, but when the pH value is between 3.5 and 7.5, hypochlorous acid (HOCl) acts as an oxidizing agent, and when the pH is below 3.5, nascent chlorine gas (Cl2) is formed. Among these three species, HOCl is [AuCl4] - It is the most effective oxidizing agent for leaching gold (reaction 8). 39 . [ka]

[0028] In a solution containing 100 g / L of NaCl, [AuCl4] - It is stable in the pH range of 0 to 8 and at potentials above 0.9V. 40 Salt compound-hypochlorite solution is a useful leaching agent, for example, for heat-resistant gold ore. Due to its low acidity, the salt compound-hypochlorite solution does not produce a corrosive medium, but the reagent consumption is still high. 41、42 The main drawback of this leaching agent is that the percentage of gold leached is usually less than 85%. 43 .

[0029] Gold leaching in organic solvents Polar and water-miscible organic solvents have been investigated for dissolving several transition metals such as silver and copper. 44、45、46 In some cases, better leaching efficiency was achieved in water-solvent or specific mixtures of pure solvents. There are also several examples of gold leaching in organic solvents such as DMSO, methanol, acetone, N,N-dimethylformamide, and acetonitrile. 45、47、48 For example, Yukimichi investigated the dissolution rates of gold, silver, and palladium in different halogen-halide polar organic solvent systems. In the case of gold, he demonstrated that gold can be dissolved in a mixture of a halide source, a halogen, such as chlorine gas, bromine, iodine, and an organic solvent such as methanol or MeCN. Of the systems investigated, a mixture of chlorine gas, acetonitrile, and Me3NHCl (as a chloride source) dissolved gold more quickly and effectively than aqua regia. 48 . [Overview of the project] [Means for solving the problem]

[0030] summary This study discloses the use of polar, water-miscible or partially water-miscible organic solvents in combination with conventional leaching reagents. Conventional leaching reagents, such as acidified chloride solutions containing oxidizing agents, have not been investigated for direct leaching of gold in organic solvents. This novel recovery system can, for example, simplify the recovery process, save considerable time and energy, and reduce waste due to the recoverability of the organic solvent.

[0031] Therefore, this application relates to a method for leaching gold, palladium, and / or platinum from a substance containing gold, palladium, and / or platinum, wherein the substance is subjected to the following conditions for leaching gold, palladium, and / or platinum from the substance: (a) Acid, (b) Oxidizing agents, and (c) Water-miscible or partially water-miscible organic solvents The method includes contacting a mixture containing the following:

[0032] In another embodiment of this application, the conditions for leaching gold, palladium, and / or platinum from a substance include stirring the substance and mixture for about 0.1 minutes to about 30 minutes at a temperature of about 10°C to about 80°C.

[0033] In embodiments, the acid in the mixture is selected from HCl, H2SO4, HBr, HNO3, H3PO4, and HI.

[0034] In another embodiment, the acid is an aqueous solution of HCl having a concentration of about 0.01 M to about 2.5 M.

[0035] In one embodiment, the oxidizing agent in the mixture is selected from H2O2, Cl2, Br2, I2, Ca(ClO)2, HNO3, MnO2, KMnO4, and K2Cr2O7. In another embodiment, the oxidizing agent is H2O2 or Ca(ClO)2.

[0036] In another embodiment of this application, the water-miscible or partially water-miscible organic solvent in the mixture is selected from acetic acid, ethyl acetate, and acetonitrile.

[0037] In some embodiments, the mixture further comprises a metal halide, an ammonium halide, a tetraalkylammonium halide, or a combination thereof. In another embodiment, the mixture further comprises a metal halide, the metal halide being CaCl2. In further embodiments, the CaCl2 in the mixture has a concentration of about 0.05 M to about 1.5 M. In embodiments of this application, reagent (a) in the mixture is HCl, reagent (b) in the mixture is H2O2, and reagent (c) in the mixture is acetic acid.

[0038] In embodiments, a substance containing gold, palladium, and / or platinum is a gold-containing substance. In embodiments, the gold-containing substance further contains iron, copper, cobalt, or nickel, or a combination thereof, and the method selectively dissolves gold from the gold-containing substance. In another embodiment of this application, the gold-containing substance is a gold-containing ore.

[0039] In one embodiment, this method uses at least 500 gm -2 h -1 , at least 1000gm -2 h -1 , or at least 5000gm -2 h -1 This provides a gold dissolution rate of approximately 500 gm. -2 h -1 ~About 9500gm -2 h -1 , or approximately 1000gm -2 h -1 ~About 9500gm -2 h -1 It provides a gold dissolution rate.

[0040] In alternative embodiments, the substance containing gold, palladium, and / or platinum is a platinum group metal concentrate.

[0041] In embodiments, the method further includes: Separation of water-miscible or partially water-miscible organic solvents containing leached gold, palladium, and / or platinum from insoluble impurities, and Evaporating water-miscible or partially water-miscible organic solvents from leached gold, palladium, and / or platinum.

[0042] In another embodiment, the method involves leaching gold, palladium, and / or platinum after evaporation using a compound of formula I, [ka] During the ceremony, R 1is -NR 4 R 5 or aryl, R 2 and R 3 are each independently H, C 1-10 alkyl, C 3-10 cycloalkyl, C 1-6 alkylene C 3-10 cycloalkyl, heterocycloalkyl, and aryl, or R 2 and R 3 are, together with the nitrogen atom to which they are attached, heterocycloalkyl or heteroaryl, or, at one or more carbon atoms, C 1-4 alkyl - substituted heterocycloalkyl or heteroaryl, R 4 and R 5 are each independently H, C 1-10 alkyl, C 3-10 cycloalkyl, C 1-6 alkylene C 3-10 cycloalkyl, heterocycloalkyl, and aryl, or R 4 and R 5 are, together with the nitrogen atom to which they are attached, heterocycloalkyl or heteroaryl, or, at one or more carbon atoms, C 1-4 alkyl - substituted heterocycloalkyl or heteroaryl, X is O or S, Y is S, NR 6 or CR 6 R 7 and [[ID=6O]]R 6 and R 7 are each independently H, C 1-10 alkyl, C 3-10 cycloalkyl, C 1-6 alkylene C 3-10The method further comprises treating a compound selected from cycloalkyl, heterocycloalkyl, and aryl compounds under conditions for forming a complex between the compound of formula I and leached gold and / or palladium.

[0043] In this embodiment, the compound of formula I is the compound of formula I(a), [ka] In the formula, R 2 , R 3 , R 4 , R 5 , and Y are as defined in the compound of formula I.

[0044] In embodiments, the conditions for forming a complex with the compound of formula I and leached gold and / or palladium include treating leached gold, palladium, and / or platinum in a non-aqueous miscible organic solvent with the compound of formula I for a period of time from about 2 minutes to about 30 minutes at a temperature of about 10°C to about 40°C.

[0045] In another embodiment, the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene.

[0046] In embodiments, the method further comprises stripping gold and / or palladium from a complex of the compound of formula I and leached gold and / or palladium by treating a non-aqueous miscible organic solvent containing the compound of formula I and the leached gold and / or palladium with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase containing the compound of formula I.

[0047] In another embodiment, the method further comprises separating a gold and / or palladium-containing strip solution from a gold and / or palladium-reduced organic phase containing a compound of formula I, and recovering gold and / or palladium from the gold and / or palladium-containing strip solution by electrolytic extraction or reduction.

[0048] In an alternative embodiment, the method further includes: To separate water-miscible or partially water-miscible organic solvents containing leached gold, palladium, and / or platinum from insoluble impurities. Under conditions for obtaining gold, palladium, and / or platinum, the treatment of leached gold, palladium, and / or platinum in a water-miscible or partially water-miscible organic solvent with a reducing agent, and Separation of gold, palladium, and / or platinum from water-miscible or partially water-miscible organic solvents.

[0049] In the embodiment, the reducing agent is selected from NaBH4, ferrocene, Fe powder, and Zn powder.

[0050] In another embodiment, the method further includes reusing a water-miscible or partially water-miscible organic solvent.

[0051] In one embodiment, the method separates gold, palladium, and / or platinum from a water-miscible or partially water-miscible organic solvent, Dissolving gold, palladium, and / or platinum in aqua regia, Dissolved gold, palladium, and / or platinum, a compound of formula I, [ka] During the ceremony, R 1 -NR 4 R 5 or aryl, R 2 and R3 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 2 and R 3 Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C 1-4 Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, R 4 and R 5 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 4 and R 5 Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C 1-4 Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, X is either O or S, Y is S, NR 6 , or CR 6 R 7 And, R 6 and R 7 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 The further comprises treating a compound selected from cycloalkyl, heterocycloalkyl, and aryl compounds under conditions for forming a complex between the compound of formula I and dissolved gold and / or palladium.

[0052] In embodiments, the conditions for forming a complex with the compound of formula I and dissolved gold and / or palladium include treating dissolved gold, palladium, and / or platinum in a non-aqueous miscible organic solvent with the compound of formula I for a period of time from about 2 minutes to about 30 minutes at a temperature of about 10°C to about 40°C.

[0053] In another embodiment, the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene.

[0054] In embodiments, the method further comprises stripping gold and / or palladium from a complex of the compound of formula I and dissolved gold and / or palladium by contacting a non-aqueous miscible organic solvent containing the compound of formula I and the complex with dissolved gold and / or palladium with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase containing the compound of formula I.

[0055] In another embodiment, the method further comprises separating a gold and / or palladium-containing strip solution from a gold and / or palladium-reduced organic phase containing a compound of formula I, and recovering gold and / or palladium from the gold and / or palladium-containing strip solution by electrolytic extraction or reduction.

[0056] Other features and advantages of this application will become apparent from the detailed description below. However, it should be understood that while embodiments of this application are shown, the detailed description and specific examples are provided for illustrative purposes only, and the scope of the claims should not be limited by these embodiments, but should be given the broadest possible interpretation consistent with the overall description. [Brief explanation of the drawing]

[0057] The present application will be described in more detail below with reference to the drawings.

[0058] [Figure 1] This figure shows a schematic diagram of a gold recovery process using cyanide leaching according to prior art.

[0059] [Figure 2] This plot shows the Au recovery rate (%) as a function of time (hours) for simultaneous leaching and extraction using the embodiment of the method of this application, compared to conventional leaching.

[0060] [Figure 3] This figure shows a schematic diagram of a method for leaching and extracting gold from gold-containing materials.

[0061] [Figure 4] This figure shows a schematic diagram of a method for leaching gold from a gold-containing substance according to an embodiment of the method described in this application.

[0062] [Figure 5] This plot shows a comparative study of gold dissolution rates in aqua regia, concentrated HCl / H2O2, and acetic acid systems.

[0063] [Figure 6] This paper presents a competitive study of the dissolution rates of gold against base metals in (a) a concentrated HCl / H2O2 mixture (4 parts HCl (37%) and 1 part H2O2 (30%)) versus acetic acid (containing 1.5 M HCl, 0.6 M H2O2, and 0.6 M CaCl2), and (b) an acetonitrile solution (containing 1 M HCl and 0.2 M H2O2) versus acetic acid (containing 0.5 M HCl, 0.2 M H2O2, and 0.2 M CaCl2). [Modes for carrying out the invention]

[0064] Detailed explanation I. Definition Unless otherwise specified, the definitions and embodiments described in this and other sections are intended to be applicable to all embodiments and aspects of this application described herein, as they are preferred to be understood by those skilled in the art.

[0065] As used herein, terms such as "compound of this application" refer to the compound of formula I as defined herein.

[0066] In understanding the scope of this application, the term “comprising” and its derivatives, as used herein, are intended to be open-ended terms that specify the existence of features, elements, components, groups, integers, and / or steps not otherwise stated, but without prejudice. The foregoing also applies to words having similar meanings, e.g., “including,” “having,” and their derivatives. The term “consisting” and its derivatives, as used herein, are intended to be closed terms that specify the existence of features, elements, components, groups, integers, and / or steps not otherwise stated, but without prejudice. As used herein, the term "consisting essentially of" is intended to identify the presence of features, elements, components, groups, integers, and / or steps described above, as well as those that do not materially affect the fundamental and novel characteristics of the features, elements, components, groups, integers, and / or steps.

[0067] As used herein, terms of degree such as “substantially,” “about,” and “approximately” mean a reasonable deviation of the modified term such that the final result is not substantially altered. These terms of degree should be interpreted as including a deviation of at least ±5% of the modified term, provided that this deviation does not negate the meaning of the word they modify.

[0068] As used herein, the terms "and / or" mean that the listed items exist or are used individually or in combination. In short, the terms mean that "at least one" or "one or more" of the listed items are used or exist.

[0069] In use in this application, the singular forms "a," "an," and "the" refer to multiple subjects unless otherwise explicitly indicated. For example, an embodiment containing "a compound" should be understood to present a particular embodiment having one compound or two or more additional compounds.

[0070] In embodiments comprising an “additional” or “second” component, for example, an additional or second compound, the second component used herein is chemically different from the other components or the first component. The “third” component is different from the other, first, and second components, and any further listed or “additional” components are similarly different.

[0071] In embodiments of this application, the compounds described herein have at least one chiral center. If a compound has multiple chiral centers, they may exist as diastereomers. It should be understood that all such isomers and mixtures thereof in any proportion are included within the scope of this application. The stereochemistry of a compound may be as shown for any given compound enumerated herein, but it should be further understood that such compounds may also contain certain amounts (e.g., less than 20%, preferably less than 10%, more preferably less than 5%) of the compounds of this application having alternative stereochemistry. Any optical isomers, such as separated, pure or partially purified optical isomers, or racemic mixtures thereof, are intended to be included within the scope of this application.

[0072] As used herein, the term “preferred” means that the selection of a particular reagent or condition depends on the reaction being performed and the desired outcome, but is generally possible for those skilled in the art, provided all relevant information is known.

[0073] As used herein in relation to two liquid phases, the term “immiscible” means that, under the conditions of use, for example, the relative proportions of the two liquid phases and / or temperature, the two liquid phases cannot be mixed to form a single-phase solution. For example, two immiscible liquid phases will separate into two liquid phases after mixing. For example, each of these two liquid phases may contain a small amount of the other liquid phase. Thus, a “water-miscible” liquid, such as a “water-miscible organic solvent,” is a liquid that, under the conditions of use, cannot be mixed with water to form a single-phase solution, but may contain a small amount of water after being mixed with water, for example.

[0074] As used herein in relation to two liquid phases, the term “partially miscible” means, for example, that two liquid phases separate into two liquid phases after mixing, with each liquid phase containing a portion of the other liquid phase in a dissolved state. Thus, “partially water-miscible organic solvent” is a liquid that, after mixing with water, separates into two liquid phases: one phase is water containing, in a dissolved state, a portion, for example, about 10% (v / v) of a partially water-miscible organic liquid, and the other phase is a partially water-miscible organic liquid containing, in a dissolved state, a portion, for example, about 10% (v / v) of water.

[0075] As used herein in relation to two liquid phases, the term “miscible” means that, for example, the two liquid phases can be mixed in all proportions to form a homogeneous solution. For example, two miscible liquid phases do not separate into two liquid phases after mixing. Therefore, a “water-miscible” liquid, such as a “water-miscible organic solvent,” is a liquid that can be mixed with water to form a homogeneous solution.

[0076] As used herein, the term “alkyl” means a linear or branched saturated alkyl group, whether used alone or as part of another group. The number of carbon atoms in the referenced alkyl group is determined by the number prefix “C”. n1-n2 This is shown by ". For example, C 1-10 The term alkyl refers to an alkyl group having 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms.

[0077] As used herein, the term "alkylene," whether used alone or as part of another group, means a linear or branched saturated alkylene group, i.e., a saturated carbon chain containing substituents on two of its ends. The number of carbon atoms possible in the referenced alkylene group is indicated by the number prefix "C". n1-n2 This is shown by ". For example, C 1-6 The term alkylene refers to an alkylene group having 1, 2, 3, 4, 5, or 6 carbon atoms.

[0078] As used herein, the term "cycloalkyl" means a saturated alkyl group having at least one cyclic ring, whether used alone or as part of another group. The number of carbon atoms possible in a referenced cycloalkyl group is indicated by the number prefix "C". n1-n2 This is shown by ". For example, C 3-10 The term cycloalkyl refers to a cycloalkyl group having 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms.

[0079] As used herein, the term “heterocycloalkyl” refers to a non-aromatic ring-containing group having one or more polyvalent heteroatoms independently selected from N, O, and S as part of a ring structure, whether used alone or as part of another group, and containing at least three and up to 20 atoms within the ring. Heterocycloalkyl groups may be saturated or unsaturated (i.e., containing one or more double bonds) and may contain multiple rings.

[0080] As used herein, the term “aryl” refers to a cyclic group containing at least one aromatic ring, whether used alone or as part of another group. In embodiments of this application, the aryl group contains 6, 9, 10, or 14 atoms and is, for example, phenyl, naphthyl, indanyl, or anthracenyl.

[0081] As used herein, the term "heteroaryl" refers to an aromatic ring-containing group having one or more polyvalent heteroatoms independently selected from N, O, and S as part of a ring structure, whether used alone or as part of another group, and containing at least five and up to twenty atoms within the ring. A heteroaryl group may contain multiple rings.

[0082] II. Application method This study discloses the use of polar, water-miscible or partially water-miscible organic solvents in combination with conventional leaching reagents. Conventional leaching reagents, such as acidified chloride solutions containing oxidizing agents, were not investigated for direct leaching of gold in organic solvents. Many leaching reagents were investigated in this study. Using a mixture of HCl in ethyl acetate or acetonitrile with H2O2 or Ca(ClO)2, over 99.9% gold leaching was achieved in a short time with 1M HCl using very low concentrations of oxidants. The results show that these novel leaching systems can dissolve gold much more rapidly than aqua regia, despite the very low relevant concentrations of the material being leached. The leached gold is then leached with, for example, NaBH4, zinc, or AuCl4 with ferrocene. -It can be precipitated from an ethyl acetate or acetonitrile solution by direct reduction. During the reduction of gold, some other impurities can be reduced, so that the obtained gold precipitate can then be purified, for example, by solvent extraction using a compound of formula I as defined herein. In some embodiments, this novel recovery system, for example, simplifies the recovery process, saves a significant amount of time and energy, and reduces waste due to the recoverability of the organic solvent.

[0083] Therefore, the present application relates to a method for leaching gold, palladium, and / or platinum from a substance containing gold, palladium, and / or platinum, comprising contacting the substance with a mixture comprising the following, under conditions for leaching gold, palladium, and / or platinum from the substance: (a) an acid, (b) an oxidizing agent, and (c) a water-miscible or partially water-miscible organic solvent The method includes contacting with the mixture.

[0084] In embodiments, the method further comprises: separating a water-miscible or partially water-miscible organic solvent containing the leached gold, palladium, and / or platinum from insoluble impurities, and evaporating the water-miscible or partially water-miscible organic solvent from the leached gold, palladium, and / or platinum.

[0085] The water-miscible or partially water-miscible organic solvent containing the leached gold, palladium, and / or platinum and the insoluble impurities are separated by any suitable means, and the selection can be made by those skilled in the art.

[0086] A water-miscible or partially water-miscible organic solvent is evaporated from the leached gold, palladium, and / or platinum by any suitable means, the choice of which can be made by those skilled in the art. In embodiments, distillation is used to evaporate a water-miscible or partially water-miscible organic solvent from the leached gold, palladium, and / or platinum.

[0087] In another embodiment, the method involves leaching gold, palladium, and / or platinum after evaporation using a compound of formula I, [ka] During the ceremony, R 1 -NR 4 R 5 or aryl, R 2 and R 3 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 2 and R 3 Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C 1-4 Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, R 4 and R 5 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 4 and R 5These, together with the nitrogen atom to which they are bonded, form a heterocycloalkyl or heteroaryl, or a heterocycloalkyl or heteroaryl in which one or more carbon atoms are substituted with C1-4 alkyl. X is either O or S, Y is S, NR 6 , or CR 6 R 7 And, R 6 and R 7 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 The process further comprises treating a compound selected from cycloalkyl, heterocycloalkyl, and aryl compounds under conditions for forming a complex between the compound of formula I and leached gold and / or palladium. Under such conditions, platinum does not form a complex with, for example, the compound of formula I.

[0088] In one embodiment, R 1 -NR 4 R 5 That is the case.

[0089] In an alternative embodiment, R 1 is an aryl. In another embodiment, R 1 C 6-10 It is an aryl. In a further embodiment, R 1 It is phenyl.

[0090] In another embodiment, the compound of formula I is the compound of formula I(a): [ka] In the formula, R 2 , R 3 , R 4 , R 5 , and Y are as defined in the compound of formula I.

[0091] In embodiments of this application, for example, in a compound of formula I(a), R 2 , R 3 , R 4 , and R 5 Only one of them is H.

[0092] In another embodiment of this application, for example, in a compound of formula I(a), R 2 and R 3 However, together with the nitrogen atom to which they are bonded, they form heterocycloalkyl, heteroaryl, or substituted heterocycloalkyl or substituted heteroaryl compounds.

[0093] In the embodiment, for example, in a compound of formula I(a), R 2 and R 3 However, together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or substituted heterocycloalkyl. In another embodiment, for example, in a compound of formula I(a), R 2 and R 3 However, together with the nitrogen atom to which they are bonded, they form heterocycloalkyl or substituted heterocycloalkyl groups, which include azilidinyl, azetidinyl, pyrrolidinyl, piperidinyl, azepanyl, azokanyl, imidazolidinyl, oxazolidinyl, thiazolidinyl, piperazinyl, hexahydropyrimidinyl, morpholinyl, 1,3-oxazinyl, thiomorpholinyl, and 1,3-thiazolidinyl. Selected from dinanyl, 1,3-diazepanyl, 1,3-oxazepanyl, 1,3-thiazepanyl, 1,4-diazepanyl, 1,4-oxazepanyl, 1,4-thiazepanyl, 1,3-diazocanyl, 1,3-oxazocanyl, 1,3-thiazocanyl, 1,4-diazocanyl, 1,4-oxazocanyl, 1,4-thiazocanyl, 1,5-diazocanyl, 1,5-oxazocanyl, and 1,5-thiazocanyl. In further embodiments, for example, in a compound of formula I(a), R 2 and R 3These, together with the nitrogen atom to which they are bonded, form morpholinyl, pyrrolidinyl, or 4-methylpiperidinyl. In embodiments, for example, in a compound of formula I(a), R 2 and R 3 These, together with the nitrogen atom to which they bond, form morpholinyl. In another embodiment, for example, in a compound of formula I(a), R 2 and R 3 These, together with the nitrogen atom to which they are bonded, form pyrrolidinyl. In a further embodiment, for example, in a compound of formula I(a), R 2 and R 3 These, together with the nitrogen atom to which they bond, form 4-methylpiperidinyl.

[0094] In the embodiment, for example, in a compound of formula I(a), R 2 and R 3 However, together with the nitrogen atom to which they bond, they form a heteroaryl or substituted heteroaryl. In another embodiment of this application, for example, in a compound of formula I(a), R 2 and R 3 These, together with the nitrogen atom to which they bond, form a heteroaryl group. In a further embodiment, for example, in a compound of formula I(a), R 2 and R 3 These, together with the nitrogen atom to which they bind, form heteroaryls selected from pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, flazanyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, 1,2,3-triazinyl, 1,2,4-triazinyl, and 1,3,5-triazinyl.

[0095] In the embodiment, for example, in a compound of formula I(a), R 4 H, C 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10Selected from cycloalkyl, heterocycloalkyl, and aryl. In another embodiment, for example, in a compound of formula I(a), R 4 H, C 1-6 Alkyl, C 3-8 Cycloalkyl, C 1-4 Alkylene, C 3-8 Selected from cycloalkyl, heterocycloalkyl, and phenyl. In a further embodiment, for example, in a compound of formula I(a), R 4 H, C 1-6 Alkyl and C 3-8 Selected from cycloalkyls. In embodiments, for example, in a compound of formula I(a), R 4 H and C 1-4 Selected from alkyl groups. In another embodiment of this application, for example, in a compound of formula I(a), R 4 H is H.

[0096] In the embodiment, for example, in a compound of formula I(a), R 5 H, C 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl. In another embodiment, for example, in a compound of formula I(a), R 5 C 3-10 Alkyl, C 3-8 Cycloalkyl, C 1-4 Alkylene, C 3-8 Selected from cycloalkyl, heterocycloalkyl, and phenyl. In a further embodiment, for example, in a compound of formula I(a), R 5 H, C 1-6 Alkyl and C 3-8 Selected from cycloalkyls. In embodiments, for example, in a compound of formula I(a), R 5 is isopropyl or cyclohexyl. In another embodiment, for example, in a compound of formula I(a), R 5is isopropyl. In a further embodiment, for example, in the compound of formula I(a), R 5 is cyclohexyl.

[0097] In an embodiment, R 1 ~R 7 at least one of any one of is aryl. In another embodiment, R 1 ~R 7 at least one of any one of is phenyl.

[0098] In an embodiment, for example, in the compound of formula I(a), R 4 is H or C 1-4 alkyl, and R 5 is C 1-6 alkyl or C 3-8 cycloalkyl. In another embodiment, for example, in the compound of formula I(a), R 4 is H, and R 5 is C 1-6 alkyl or C 3-8 cycloalkyl. In a further embodiment of the present application, for example, in the compound of formula I(a), R 4 is H, and R 5 is C 1-6 alkyl. In an embodiment, for example, in the compound of formula I(a), R 4 is H, and R 5 is C 3-8 cycloalkyl. In another embodiment, for example, in the compound of formula I(a), R 4 is H, and R 5 is isopropyl. In a further embodiment, for example, in the compound of formula I(a), R 4 is H, and R 5 is cyclohexyl.

[0099] In an embodiment, X is O. In another embodiment, X is S.

[0100] In an embodiment, Y is NR 6That is the case.

[0101] In one embodiment, R 6 H, C 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl. In another embodiment, R 6 H, C 1-6 Alkyl, C 3-8 Cycloalkyl, C 1-4 Alkilen C 3-8 Selected from cycloalkyl and heterocycloalkyl. In further embodiments, R 6 H, C 1-6 Alkyl or C 3-8 It is a cycloalkyl. 6 In one embodiment, R 6 C 1-6 It is alkyl. In another embodiment of this application, R 6 C 3-8 It is cycloalkyl. In a further embodiment, R 6 It is isopropyl. It is R 6 This embodiment involves cyclohexyl.

[0102] In one embodiment, Y is CR 6 R 7 That is the case.

[0103] In one embodiment, R 6 and R 7 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl. In another embodiment, R 6 and R 7 These are H and C, which are independent of each other. 1-6 Alkyl, C 3-8 Cycloalkyl, C 1-4 Alkylene, C3-8 Selected from cycloalkyl and heterocycloalkyl. In further embodiments, R 6 and R 7 These are H and C, which are independent of each other. 1-6 Alkyl or C 3-8 It is a cycloalkyl group.

[0104] In the embodiment, the compound of formula I is a compound of formula I(a)(i), I(a)(ii), I(a)(iii), or I(a)(iv). [ka]

[0105] In another embodiment of this application, the compound of formula I is the compound of formula I(a)(i). [ka]

[0106] In another embodiment of this application, the compound of formula I is the compound of formula I(a)(ii). [ka]

[0107] In another embodiment of this application, the compound of formula I is the compound of formula I(a)(iii). [ka]

[0108] In another embodiment of this application, the compound of formula I is the compound of formula I(a)(iv). [ka]

[0109] In another embodiment, the compound of formula I is the compound of formula I(b)(i). [ka]

[0110] In another embodiment, the compound of formula I is a compound of formula I(c)(i), I(c)(ii), I(c)(iii), or I(c)(iv), [ka] In each of the compounds of formula I(c)(i), I(c)(ii), I(c)(iii), or I(c)(iv), Z 1 and Z 2 One of them is O, and Z 1 and Z 2 The other side is S.

[0111] In embodiments, the compounds of formula I are prepared from commercially available materials using commercially available or known methods in the literature. For example, the compound of formula I(a) is prepared by adding a appropriately substituted amine to a mixture of CS2 and carbodiimide in a suitable polar solvent, such as an alcohol solvent, under conditions for forming the compound of formula I(a). The compound of formula I(a) is generally precipitated and separated from the reaction mixture and optionally purified using known methods. In embodiments, a slightly excess amount of amine and CS2, for example, 1.05 to 1.5, preferably 1.1 equivalents, is used. In embodiments, the suitable solvent is methanol or ethanol, preferably methanol. In embodiments, the reaction is carried out at room temperature or around room temperature, but the temperature can be adjusted as needed by those skilled in the art.

[0112] In embodiments, the conditions for forming a complex with the compound of formula I and leached gold and / or palladium include treating the leached gold, palladium, and / or platinum in a non-aqueous miscible organic solvent with the compound of formula I for a period of about 2 to 30 minutes at a temperature of about 10°C to about 40°C. It will be understood by those skilled in the art that the platinum remains in the aqueous phase and is not extracted into the organic phase by the compound of formula I. The platinum can be recovered from the aqueous phase by any suitable method, the choice of which can be made by those skilled in the art.

[0113] In one embodiment, the molar ratio of compound I to gold and / or palladium is about 1:10 to about 50:1. In another embodiment, the molar ratio of compound I to gold and / or palladium is about 1:1 to about 20:1. In a further embodiment, the molar ratio of compound I to gold and / or palladium is about 2:1 to about 10:1. This is an embodiment in which the molar ratio of compound I to gold and / or palladium is about 3:1 to about 4:1. In another embodiment, the molar ratio of compound I to gold and / or palladium is about 3:1. In a further embodiment, the molar ratio of compound I to gold and / or palladium is about 4:1.

[0114] In one embodiment, the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene. In another embodiment, the non-aqueous miscible organic solvent is dichloromethane.

[0115] In another embodiment, the method further comprises stripping gold and / or palladium from a complex of the compound of formula I and leached gold and / or palladium by treating a non-aqueous miscible organic solvent containing the compound of formula I and the leached gold and / or palladium complex with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase containing the compound of formula I. In an embodiment, the conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase include stirring a non-aqueous miscible organic solvent with an aqueous solution containing H2SO4, e.g., 1 M H2SO4 and thiourea, e.g., 0.7 M thiourea, for a period of about 5 minutes to about 1 hour or about 15 minutes at a temperature of about 10°C to about 40°C or about 20°C to about 25°C. Other suitable acids, such as HCl, may be used in the stripping step, but are not limited to these. However, it will be understood by those skilled in the art that HCl is corrosive and that HCl gas may be released from the solution during subsequent reduction or electrolytic extraction.

[0116] In further embodiments, the method further comprises separating a gold and / or palladium-containing strip solution from a gold and / or palladium-reduced organic phase containing the compound of formula I, and recovering gold and / or palladium from the gold and / or palladium-containing strip solution by electrolytic extraction or reduction. The gold and / or palladium-containing strip solution, and the gold and / or palladium-reduced organic phase containing the compound of formula I, can be separated by any suitable means, and the selection thereof for use in the method of this application can be made by those skilled in the art.

[0117] In an alternative embodiment, the method is To separate water-miscible or partially water-miscible organic solvents containing leached gold, palladium, and / or platinum from insoluble impurities, Under conditions for obtaining gold, palladium, and / or platinum, the leached gold, palladium, and / or platinum in a water-miscible or partially water-miscible organic solvent is treated with a reducing agent, The method further includes separating gold, palladium, and / or platinum from water-miscible or partially water-miscible organic solvents.

[0118] The leached gold, palladium, and / or platinum-containing water-miscible or partially water-miscible organic solvents and insoluble impurities can be separated by any suitable means, the selection of which can be made by those skilled in the art.

[0119] The reducing agent can be any suitable reducing agent. In embodiments of this application, the reducing agent is selected from NaBH4, ferrocene, Fe powder, and Zn powder.

[0120] In another embodiment, the method further includes reusing a water-miscible or partially water-miscible organic solvent.

[0121] In one embodiment, the method separates gold, palladium, and / or platinum from a water-miscible or partially water-miscible organic solvent, Dissolving gold, palladium, and / or platinum in aqua regia, Dissolved gold, palladium, and / or platinum, a compound of formula I, [ka] During the ceremony, R 1 -NR 4 R 5 or aryl, R 2 and R 3 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 2 and R 3 Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C 1-4 Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, R 4 and R 5 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 4 and R 5 Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C 1-4 Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, X is either O or S, Y is S, NR 6 , or CR 6 R 7 And, R 6 and R 7 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 The method further comprises treating a compound selected from cycloalkyl, heterocycloalkyl, and aryl compounds under conditions for forming a complex between the compound of formula I and dissolved gold and / or palladium. Under such conditions, platinum does not form a complex with, for example, the compound of formula I. The compound of formula I can be modified as detailed herein.

[0122] In another embodiment, the conditions for forming a complex with the compound of formula I and dissolved gold and / or palladium include treating dissolved gold, palladium, and / or platinum in a non-aqueous miscible organic solvent with the compound of formula I for a period of about 2 to 30 minutes at a temperature of about 10°C to about 40°C. It will be understood by those skilled in the art that platinum remains in the aqueous phase and is not extracted into the organic phase by the compound of formula I. The platinum can be recovered from the aqueous phase by any suitable method, the choice of which can be made by those skilled in the art.

[0123] In one embodiment, the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene. In another embodiment, the non-aqueous miscible organic solvent is dichloromethane.

[0124] In embodiments, the method further comprises stripping gold and / or palladium from a complex of the compound of formula I and dissolved gold and / or palladium by contacting a non-aqueous miscible organic solvent containing the compound of formula I and a complex of dissolved gold and / or palladium with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase containing the compound of formula I. In embodiments, the conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase include stirring a non-aqueous miscible organic solvent with an aqueous solution containing H2SO4, e.g., 1 M H2SO4 and thiourea, e.g., 0.7 M thiourea, for a period of about 5 minutes to about 1 hour or about 15 minutes at a temperature of about 10°C to about 40°C or about 20°C to about 25°C. Other suitable acids, such as HCl, may be used in the stripping step, but are not limited to these. However, it will be understood by those skilled in the art that HCl is corrosive and that HCl gas may be released from the solution during subsequent reduction or electrolytic extraction.

[0125] In another embodiment, the method further comprises separating a gold and / or palladium-containing strip solution from a gold and / or palladium-reduced organic phase containing the compound of formula I, and recovering gold and / or palladium from the gold and / or palladium-containing strip solution by electrolytic extraction or reduction. The gold and / or palladium-containing strip solution, as well as the gold and / or palladium-reduced organic phase containing the compound of formula I, can be separated by any suitable means, and the selection thereof for use in the method of this application can be made by those skilled in the art.

[0126] In one embodiment, gold or palladium is recovered from the gold and / or palladium-containing strip solution by electrolytic extraction.

[0127] In another embodiment, gold and / or palladium are recovered from the gold and / or palladium-containing strip solution by reduction. The reducing agent can be any suitable reducing agent. In embodiments, the reducing agent is oxalic acid, Zn powder, Fe powder, or NaBH4. In embodiments, the reducing agent is NaBH4, and temperatures of about 10°C to about 35°C or about 20°C to about 25°C are used. In another embodiment, the reducing agent is oxalic acid, and temperatures of about 40°C to about 60°C or about 50°C are used.

[0128] In embodiments, conditions for leaching gold, palladium, and / or platinum from a gold, palladium, and / or platinum-containing substance include stirring the gold, palladium, and / or platinum-containing substance and mixture at a temperature of about 10°C to about 80°C, about 10°C to about 40°C, or about 20°C to about 25°C for a period of time of about 0.1 minutes to about 4 hours, about 0.1 minutes to about 2 hours, about 0.1 minutes to about 30 minutes, or less than about 15 minutes.

[0129] The acid in the mixture can be any suitable acid, i.e., any suitable proton donor. In embodiments, the acid is a hydrogen halide (e.g., HCl, HBr, or HI), chlorous acid, chloric acid, bromic acid, bromic acid, iodic acid, iodic acid, perchloric acid, sulfuric acid, nitric acid, oxalic acid, phosphoric acid, organic acids (e.g., benzenesulfonic acid), or a combination thereof. In embodiments, the acid is selected from HCl, H2SO4, HBr, HNO3, H3PO4, and HI. In another embodiment, the acid is selected from HCl, H2SO4, HBr, and HI. In yet another embodiment, the acid is HCl. The concentration of the acid can be any suitable concentration. In embodiments, the acid is an aqueous solution of HCl having a concentration of about 0.01 M to about 4 M. In further embodiments, the acid is an aqueous solution of HCl having a concentration of about 0.5 M to about 4 M. This embodiment involves an aqueous solution of HCl having a concentration of about 1 M to 2.5 M, about 0.1 M to about 2.5 M, or about 0.01 M to about 2.5 M. In another embodiment, the acid is an aqueous solution of HCl having a concentration of about 2 M. In a further embodiment of this application, the acid is an aqueous solution of HCl having a concentration of about 1 M.

[0130] The oxidizing agent in the mixture can be any suitable oxidizing agent. In embodiments, the oxidizing agent may be ozone, nitric acid (HNO3), hydrogen peroxide (H2O2), O2, bubble air, I2, Br2, Cl2, oxone®, ammonium polyatomic salts (e.g., ammonium chlorite, ammonium periodate (NH4IO3), ammonium perborate (NH4BO3), ammonium chlorate (NH4ClO3), ammonium persulfate (NH4)2S2O8), ammonium hypochlorite, or ammonium nitrate), calcium hypochlorite, sodium polyatomic salts (e.g., sodium persulfate (Na2S2O8), sodium nitrate, etc.) The oxidizing agent may be sodium hypochlorite, potassium polyatomic salts (e.g., potassium permanganate, potassium persulfate, potassium iodate, potassium hypochlorite, or potassium nitrate), manganese oxide, tetraalkylammonium salts (e.g., tetramethylammonium chlorite (N(NH3)4)ClO2) or tetramethylammonium periodate (N(NH3)4)IO4)), peroxomonosulfate, urea, peracetic acid, alkanesulfonic acid (e.g., methanesulfonic acid), aromatic sulfonic acid (e.g., benzenesulfonic acid), or a combination thereof. In another embodiment, the oxidizing agent may be H2O2, Cl2, Br2, I2, Ca(ClO)2, HNO3, or MnO2. -The oxidizing agent is selected from KMnO4 and K2Cr2O7. In another embodiment, the oxidizing agent is H2O2 or Ca(ClO)2. In a further embodiment, the oxidizing agent is H2O2. It is an embodiment in which the oxidizing agent is Ca(ClO)2. The concentration of the oxidizing agent can be any preferred concentration. For example, water may reduce the leaching efficiency in the method of leaching gold from a gold-containing material of this application. In another embodiment, the oxidizing agent is an aqueous solution of H2O2 having a concentration of about 0.01 to about 1.0 M. In a further embodiment, the oxidizing agent is an aqueous solution of H2O2 having a concentration of about 0.05 M to about 0.5 M. It is an embodiment in which the oxidizing agent is an aqueous solution of H2O2 having a concentration of about 0.1 M to about 0.3 M. In another embodiment, the oxidizing agent is an aqueous solution of CaClO2 having a concentration of about 0.005 to about 0.5 M. In a further embodiment, the oxidizing agent is an aqueous solution of CaClO2 having a concentration of about 0.01 M to about 0.2 M. In this embodiment, the oxidizing agent is an aqueous solution of CaClO2 having a concentration of about 0.03 M to about 0.1 M.

[0131] A water-miscible or partially water-miscible organic solvent can be any suitable water-miscible or partially water-miscible organic solvent, including organic acids such as acetic acid. In an embodiment, the water-miscible or partially water-miscible organic solvent in the mixture is selected from acetic acid, ethyl acetate, acetonitrile, tetrahydrofuran (THF), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and methanol (MeOH). In another embodiment, the water-miscible or partially water-miscible organic solvent is selected from acetic acid, ethyl acetate, acetonitrile, and THF. In a further embodiment, the water-miscible or partially water-miscible organic solvent is selected from acetic acid, ethyl acetate, and acetonitrile. In another embodiment, the water-miscible or partially water-miscible organic solvent is ethyl acetate or acetonitrile. It is an embodiment in which the water-miscible or partially water-miscible organic solvent contains ethyl acetate, essentially consists of ethyl acetate, or comprises ethyl acetate. In another embodiment, the water-miscible or partially water-miscible organic solvent contains acetonitrile, is essentially derived from acetonitrile, or consists of acetonitrile. In yet another embodiment, the water-miscible or partially water-miscible organic solvent contains acetic acid, is essentially derived from acetic acid, or consists of acetic acid.

[0132] In embodiments, the mixture further comprises a metal halide, an ammonium halide, or a tetraalkylammonium halide, or a combination thereof. In embodiments, the mixture comprises a metal halide, the metal halide being an alkali metal halide, an alkaline earth metal halide, or an aluminum halide, or a combination thereof. In embodiments, the metal halide is a sodium halide, a potassium halide, a lithium halide, a calcium halide, a magnesium halide, or an aluminum halide, or a combination thereof. In embodiments, the tetraalkylammonium halide is tetra(C) 1-4Alkyl)ammonium halides, such as tetramethylammonium chloride. In embodiments, the ammonium halide is ammonium bromide or ammonium chloride, or a combination thereof. In another embodiment of this application, the mixture further comprises a reagent selected from NaCl, KCl, NaBr, KBr, NaI, KI, CaCl2, MgCl2, NH4Br, NH4Cl, and N(CH3)4Cl, or a combination thereof. In a further embodiment, the mixture further comprises a metal halide, the metal halide being CaCl2, wherein the concentration of CaCl2 in the mixture is about 0.05 M to about 1.5 M, about 0.3 M to about 0.8 M, or about 0.6 M. In another embodiment, reagent (a) in the mixture is HCl, reagent (b) in the mixture is H2O2, and reagent (c) in the mixture is acetic acid.

[0133] A substance containing gold, palladium, and / or platinum may be any suitable substance containing gold, palladium, and / or platinum. In embodiments, the substance containing gold, palladium, and / or platinum is selected from gold-containing ore, anode slime, platinum group metal (PGM)-containing materials, such as PGM concentrates, electronic scrap, and jewelry scrap.

[0134] In one embodiment, a substance containing gold and / or palladium is a gold-containing substance. In another embodiment of this application, the gold-containing substance is a gold-containing ore. In another embodiment of this application, the gold ore is an oxide gold ore. In yet another embodiment, the gold ore is a heat-resistant gold ore.

[0135] In embodiments, the gold-containing material further comprises iron, copper, cobalt, or nickel, or a combination thereof, and the method selectively dissolves gold from the gold-containing material.

[0136] In one embodiment, this method uses at least 500 gm -2 h -1 , at least 1000gm -2 h -1, or at least 5000gm -2 h -1 This provides a gold dissolution rate of approximately 500 gm. -2 h -1 ~About 9500gm -2 h -1 , or approximately 1000gm -2 h -1 ~About 9500gm -2 h -1 It provides a gold dissolution rate.

[0137] In one embodiment, a substance containing gold, palladium, and / or platinum is a palladium-containing substance. In another embodiment of this application, a palladium-containing substance is a palladium-containing ore. In one embodiment, a substance containing gold, palladium, and / or platinum is a palladium-containing substance. In another embodiment of this application, a platinum-containing substance is a platinum-containing ore.

[0138] In one embodiment, a substance containing gold, palladium, and / or platinum is a platinum group metal-containing substance. In another embodiment, the platinum group metal-containing substance is a platinum group metal concentrate. After dissolving a platinum group metal-containing substance containing platinum, palladium, rhodium, osmium, ruthenium, and iridium, it will be understood by those skilled in the art that the compound of formula I can selectively extract both palladium and gold into the organic phase and separate them from the remainder of the platinum group metals. 49

[0139] In another embodiment of this application, the method includes crushing and / or polishing a material containing gold, palladium, and / or platinum, such as gold-containing ore, into particles before contact with a mixture. In a further embodiment, the particle size of the material containing gold, palladium, and / or platinum, such as gold-containing ore, is about 75 micrometers or less.

[0140] The following non-limiting examples illustrate the present application.

[0141] Examples Example 1: A novel leaching method using sulfur-based ligands to selectively extract and recover gold. General ligand synthesis The ligands I(a)(i), I(a)(ii), I(a)(iii), and I(a)(iv) (Scheme 2) used in this study were synthesized according to the following reported literature procedure. 49 Ligand I(b)(i)(N-phenyl-N'-benzoylthiourea) was synthesized according to the reported procedure. 50

[0142] For example, for ligands I(a)(i) to I(a)(iv), 1.1 equivalents of the substituted amine were gradually added over 1 hour to a mixture of 1.3 equivalents of CS2 and 1 equivalent of carbodiimide in methanol in a round-bottom flask at room temperature. The reaction mixture was stirred for 4 hours, and the resulting white precipitate was separated from the solution by filtration. Finally, the white precipitate was washed with water and dried under vacuum.

[0143] Ligand L 1 synthesis In a round-bottom flask, 2.02 g of pyrrolidine was gradually added over 1 hour to a mixture of 2.80 g of CS2 and 5.85 g of dicyclohexylcarbodiimide (DCC) in 30 ml of methanol at room temperature. The reaction mixture was stirred for 4 hours, and the resulting white precipitate was separated from the solution by filtration. Finally, the white precipitate was washed with water and dried under vacuum. 8.93 g of the final product was isolated (yield: 89%).

[0144] Preparation of gold powder Gold powder was prepared by applying the method reported by Jeffrey et al. 511,000 g of pure (99.9% purity) metallic gold was dissolved in 4 mL of aqua regia (3 mL of 37% HCl / 1 mL of 69% HNO3), and then diluted five-fold by adding distilled water. Sodium metabisulfite was gradually added to the solution while gently stirring. Na2S2O5 was continued to be added until all the gold precipitated from the solution (the solution changed color from yellow to colorless). The resulting precipitate was isolated, washed with 1 M HCl, then with distilled water, and finally dried in an oven. 0.975 g of pale brown gold powder was obtained (yield: 97.5%).

[0145] (a) Simultaneous leaching and solvent extraction Effect of HCl concentration 5.0 mg of gold powder (0.025 mmol) was added to vials containing 5 ml of HCl solution at different concentrations (0.1, 0.5, 1, 1.5, and 2 M) and 0.22 M HNO3. Then, 26.8 mg (0.075 mmol) of ligand I(a)(i) was dissolved in 5 ml of dichloromethane and added to the previous solutions. The reaction mixture was vigorously stirred for different durations. Once the reaction was complete, the two phases were separated, and the organic phase was stripped with 1 M H2SO4 (1 M) in 5 ml of 0.7 M thiourea for 15 minutes.

[0146] The gold content of the strip solutions was analyzed by AAS. Initial investigations (Table 1) showed a significant difference between conventional leaching with HCl / HNO3 and co-leaching and extraction using dithiobiuret ligands (item 3 vs 4). While we do not wish to be limited by theory, the initial trace amounts of leached gold are extracted into the organic phase by sulfur-based ligands, driving a gold leaching equilibrium (Scheme 1) that leads to an increased leaching reaction rate. [ka]

[0147] The results showed no significant gold recovery at low HCl concentrations (items 1 and 2). However, by increasing the HCl concentration, gold could be completely recovered at HCl concentrations of 1 M or higher. As shown in Table 1, when the HCl concentration was 1 M (item 4), a recovery rate of over 99% was achieved in 4 hours, and the recovery time was shorter at higher molar concentrations (items 5 and 6). For this reason, 1 M (mol / L) HCl was selected as the acid concentration for other experiments.

[0148] The effect of stirring time 5.0 mg of gold powder (0.025 mmol) was added to a vial containing 5 ml of 1 M HCl and 0.22 M HNO3. Then, 26.8 mg (0.075 mmol) of ligand L1 was dissolved in 5 ml of dichloromethane and added to the previous solution. The reaction mixture was vigorously stirred for different amounts of time. Once the reaction was complete, the two phases were separated, and the organic phase was stripped with 5 ml of H2SO4 (1 M) containing 0.7 M thiourea for 15 minutes. The gold content of the stripped solution was analyzed by AAS. The results obtained (Figure 2) showed that the gold recovery percentage increased rapidly by the co-leaching and extraction system until it reached 99% after 4 hours and remained constant. This is significantly faster than conventional leaching systems with the same amounts of HCl and HNO3. It was found that a useful leaching time for recovering Au using this system is 4 hours in a 1 M HCl solution.

[0149] A comparison of the method used in this study with conventional leaching systems demonstrates that the dithiobiuret ligand can efficiently improve the rate of gold leaching with minimal amounts of acid and oxidizing reagents. In addition to the leaching step, the novel technique simultaneously recovers gold from the aqueous solution, thereby significantly reducing the overall gold recovery time compared to cyanide leaching followed by activated carbon adsorption.

[0150] Effects of ligand concentration 5.0 mg of gold powder (0.025 mmol) was added to a vial containing 5 ml of 1 M HCl and 0.22 M HNO3. Then, different amounts of ligand L1 (Table 2) were dissolved in 5 ml of dichloromethane and added to the previous solution. The reaction mixture was vigorously stirred for 4 hours. Once the reaction was complete, the two phases were separated, and the organic phase was stripped with 5 ml of 1 M H2SO4 containing 0.7 M thiourea for 15 minutes. The gold content of the stripped solution was analyzed by AAS.

[0151] Table 2 shows the gold recovery percentages for different ligand-to-Au ratios. With a 1:1 molar ratio and optimized HCl and oxidant concentrations, only 42% of gold was recovered. Gold recovery increased with increasing ligand concentration in the organic solvent, and was virtually complete at a 3:1 molar ratio (L:Au).

[0152] Efficiency of different ligand derivatives Different dithiobiuret ligand derivatives (I(a)(i) to I(a)(iv)) were synthesized, and their capabilities for simultaneous leaching and extraction of gold in an HCl medium were investigated (Scheme 2). Compared with the monodentate thiourea derivative (L1) and the conventional gold extractant dibutylcarbitol (DBC), all dithiobiuret derivatives showed higher percentage gold recovery. [ka]

[0153] Among the different dithiobiuret derivatives (I(a)(i) to I(a)(iv)), I(a)(i) showed the highest Au recovery rate. DBC is the most common gold extractant used for selective extraction of gold from acidic solutions. Although DBC is an effective gold extractant in conventional solvent extraction techniques, it showed very low gold recovery rates under these simultaneous leaching and extraction conditions, even at extremely high concentrations of the extractant (item 6, Table 3).

[0154] Ligand I(b)(i) was also investigated. 5.0 mg of gold powder (0.025 mmol) was added to a vial containing 5 ml of HCl (1 M) and HNO3 (0.22 M). Then, 20.3 mg (0.075 mmol) of synthetic ligand I(b)(i) was dissolved in 5 ml of dichloromethane and added to the previous solution. The reaction mixture was vigorously stirred for 6 hours. Once the reaction was complete, the two phases were separated, and the organic phase was stripped with 5 ml of H2SO4 (1 M) containing 0.7 M thiourea for 15 minutes. The gold content of the strip solution was analyzed by AAS. The results showed that 99.0% of the gold was recovered.

[0155] Selectivity To investigate the selectivity of this technique, mixtures of different metals in chloride form were treated in a system. A mixture of Fe (1000 ppm), Cu (2000 ppm), Zn (500 ppm), Ag (200 ppm), and 0.5 mg of gold powder was added to a vial containing 5 ml of 1 M HCl and 0.2 M HNO3. Then, 26.8 mg of ligand L1 was dissolved in 5 ml of dichloromethane and added to the previous solution. The reaction mixture was vigorously stirred for different times. Once the reaction was complete, the two phases were separated, and the organic phase was stripped with 5 ml of 1 M H2SO4 containing 0.7 M thiourea for 15 minutes. The gold content of the post-extraction and stripped solutions was analyzed by AAS.

[0156] The results shown in Table 4 demonstrate that the co-leaching and extraction technique using dithiobiuret ligands is highly selective for gold, resulting in the extraction of only trace amounts of base metals, even in the presence of large amounts of free ligands. In contrast to the cyanide process, this technique can eliminate, for example, the entire activated carbon step required to separate gold from other impurities.

[0157] Effects of organic solvents Simultaneous leaching and extraction tests were performed in non-aqueous miscible organic solvents shown in Table 5. The results indicate that many organic solvents are suitable for extracting and recovering gold. Among the solvents investigated, the highest percentage of Au recovery was obtained when using dichloromethane (DCM), chlorobenzene, or chloroform as the solvent.

[0158] (b) Processing of gold ore The crushed and polished gold ore, with an average gold concentration of 7 ppm and an average grain size of 74 micrometers, was obtained from Claude Resources' Seabee gold mining operations. The ore is located in the La Ronge Mining District at the northern end of Laonil Lake, approximately 125 kilometers northeast of the town of La Ronge, Saskatchewan.

[0159] General experiments for simultaneous leaching and solvent extraction: Figure 3 shows a method flowchart for the simultaneous leaching and solvent extraction technique 200 of this embodiment. In method 200, crushed and polished gold ore 202 having an average particle size of 74 micrometers was subjected to the simultaneous leaching and extraction step 204. The ore 202 was added to a 1 M HCl solution in the presence of HNO3, and then a dichloromethane ligand I(a)(i) solution was added to the aqueous solution 206. The resulting two-phase reaction mixture was vigorously stirred for 5 hours. The mixture was then filtered to remove solid residue 208, and the phases were separated into an organic phase 212 and an aqueous phase 214 210. The aqueous phase 214 can be reused for use in the simultaneous leaching and extraction step 204. The organic phase 212 was then stripped with 1 M H2SO4 containing 0.7 M thiourea 218 for 15 minutes 216, and the gold content of the stripped solution was analyzed by AAS, which consistently shows a gold recovery efficiency in the range of 95-97%. After the stripping step 216, the ligand and DCM can be reused for use in the simultaneous leaching and extraction step 204 220. Electrolytic extraction or reduction step 222 can be performed to isolate pure gold 224. Alternatively, instead of the stripping step 216, the organic phase 212 can be reduced with an agent such as oxalic acid or NaBH4 226 to obtain pure gold 228. If the organic phase is sensitive to the reducing agent, the use of thiourea stripping of gold from the dithiobiuret gold complex 216 may be used. However, direct reduction of the packed organic phase 226 may be more economical. For example, in method 200, which includes stripping of the organic phase 216, metallic gold 224 is obtained using the subsequent electrolytic extraction or reduction step 222, whereas in method 200, which includes a direct reduction step 226, metallic gold 228 can be obtained in one less step. In this experiment, low concentrations of gold were used in the sample, and the efficiency of the system was measured, so the final gold solution was analyzed. Therefore, instead of weighing the precipitated gold, the organic phase was typically removed, and the gold content was measured by AAS.

[0160] Exemplary experiments for simultaneous leaching and solvent extraction: 5.0 g of crushed and polished gold ore with an average particle size of 74 micrometers was added to a vial containing 5 ml of 1 M HCl and 0.55 M HNO3. Then, 27.8 mg of ligand I(a)(i), dissolved in 5 ml of dichloromethane, was added to the aqueous solution. The reaction mixture was vigorously stirred for 5 hours. The two-phase reaction mixture was then filtered to isolate the organic phase. The organic phase was then stripped with 5 ml of 1 M H2SO4 containing 0.7 M thiourea for 15 minutes, and the gold content of the stripped solution was analyzed by AAS. The final solution contained 6.7 ppm gold (96% gold recovery).

[0161] (c) Comparative example: Treatment of gold ore with cyanide solution: 5.00 g of gold ore was added to a vial containing 10 ml of basic solution (pH=10.5, pH adjusted by dissolving an appropriate amount of KOH in distilled water). 0.20 g of KCN was added to the solution, and the reaction mixture (with air open) was vigorously stirred for 24 hours. The reaction mixture was weighed before the start of the reaction and after the completion of the reaction to estimate the amount of water evaporated during the leaching process. Then, an appropriate amount of water was added to the reaction mixture to maintain a constant slurry density. The gold content of the resulting solution was measured by atomic absorption spectroscopy.

[0162] This experiment was conducted to determine the amount of gold in the ore samples and to compare the efficiency of the solvent extraction technique in this study with that of the cyanide leaching process. Twenty cyanide experiments were repeated on gold ore from the Claude Resources mine, and the results showed an average gold content of 9.5–10 ppm.

[0163] (d) Discussion: Solvent extraction technique as a leaching technique Suitable sulfur-containing compounds are useful candidates for recovering gold from ore because they align with Pearson's concept of "hard acids / soft acids and hard bases / soft bases," where precious metals such as gold are typically classified as soft acids, while sulfur-containing compounds are classified as soft bases. For this reason, suitable sulfur-containing ligands, such as chelating ligands, can be used as highly selective extractants for extracting and recovering gold.49 . [ka]

[0164] Equation I (wherein R, for example, 1 -NR 4 R 5 X is S, Y and R 2 ~R 5 Compounds of formula I (wherein R is defined herein) are useful for selectively extracting precious metals such as gold from aqueous solutions. 1 is aryl, X is O, and R 1 ~R 3 Compounds of (as defined herein) are also useful for selectively extracting precious metals such as gold from aqueous solutions. For example, when X is S, the ligand has two strong donor sites (thiocarbonyl groups) to bond with the precious metal, which make the ligand a strong bidentate ligand capable of forming an extremely stable six-membered ring complex with a precious metal such as gold (e.g., formula II(a) (wherein M is a precious metal, e.g., Au, Y and R) 2 ~R 5 (as defined herein) [ka]

[0165] In addition, based on the resonance contributors represented in Scheme 3, the nitrogen atom increases Lewis basicity with the sulfur atom, making it more likely to donate sulfur electrons to the metal center (further resonance contributors exist when Y=N or S, rather than Y=C). [ka]

[0166] Ligand (where X=O and R) 1The aryl ligand behaves similarly, but takes longer to dissolve gold, for example, it was found to take 6 hours to completely dissolve gold, compared to 4 hours for the dithiobiuret ligand (X=S) studied.

[0167] In a typical known solvent extraction process, the desired metal is first dissolved in water using a large amount of acid in the presence of an oxidant, such as hydrogen peroxide or HNO3. In the second step, the metal is then extracted into an organic phase. Subsequently, other metal impurities, similarly extracted during the process, are removed, usually requiring further processing. The solvent is then removed, and the desired metal is reduced to its original base metal form.

[0168] Hydrochloric acid combined with strong oxidants such as HNO3, H2O2, and Cl2 is a well-known leaching medium for gold and other transition metals, but high efficiency is achieved only when high concentrations of acid and oxidants are used. In known processes, the leaching reaction rate decreases dramatically by reducing the hydrochloric acid concentration. However, by maintaining high concentrations of oxidants and HCl, their consumption is uneconomical and produces an extremely corrosive medium. In addition, in the case of gold ore, the temperature is also typically increased to obtain effective leaching.

[0169] The dithiobiuret derivatives shown in Scheme 4 are disclosed as ligands for selectively extracting gold from a hydrochloric acid medium. 49 . [ka]

[0170] In this study, both the leaching and extraction steps are carried out simultaneously under mild conditions that increase the overall efficiency of the process. As shown in Scheme 1 above, this is achieved by shifting the reaction equilibrium to the right by drawing the dissolved gold from an aqueous solution containing small amounts of acid and oxidant into an organic phase containing ligands. In such a process, highly efficient ligands are used that enable the extraction of even very small amounts of dissolved gold.

[0171] In known processes, solvent extraction is typically applied after the leaching step. To the best of our knowledge, performing both steps simultaneously to improve the leaching step (and the overall extraction rate) has not been reported.

[0172] Example 2: Simultaneous leaching and solvent extraction of palladium 5.0 mg of palladium powder (0.047 mmol) was added to a vial containing 5 ml of water with HCl (1 M) and HNO3 (0.22 M). Then, 64.95 mg (0.184 mmol) of ligand I(a)(i) was dissolved in 5 ml of dichloromethane and added to the previous solution. After 2 hours, the palladium was completely dissolved. The two phases were separated, and the organic phase (dark brown) was stripped with 5 ml of H2SO4 (1 M) containing 0.7 M thiourea for 15 minutes. The yellow precipitate was then filtered off and heated in a furnace to 700°C to produce fine black palladium powder (99.3% of palladium was recovered).

[0173] Example 3: Gold leaching in organic solvents A mixture of hydrochloric acid and hydrogen peroxide was selected as a leaching agent in different water-miscible or partially water-miscible organic solvents. 5.0 mg of gold powder was added to 5 ml of organic solvent containing 500 mg of concentrated HCl (37% w / w) and 60 mg of H2O2 (30% w / w). After the reaction was complete, the dissolved gold was precipitated, the resulting precipitate was dissolved in aqua regia, and purified by solvent extraction. 49 The gold content of the final solution was analyzed by AAS. If gold dissolution was incomplete, the packed organic phase was separated from the remaining gold by filtration.

[0174] Among the different solvents shown in Table 6, both ethyl acetate and acetonitrile exhibited the maximum % Au leaching rate in a very short time (14 minutes), even with low concentrations of HCl (1M). These results demonstrate very short leaching times with ethyl acetate or acetonitrile solutions containing small amounts of both HCl and H2O2.

[0175] Table 7 provides an overview of the results of gold leaching in ethyl acetate, acetic acid, and acetonitrile, with different concentrations of HCl and oxidant (H2O2 or Ca(ClO)2) compared to a system using aqua regia. In each test, 5.0 mg of gold powder was dissolved in 5 mL of organic solvent containing different amounts of HCl and oxidant, as shown in Table 7. Much higher concentrations of oxidant (HNO3) and HCl were used compared to the aqua regia system than to the system using organic solvents.

[0176] The leaching rate observed in these experiments is sufficiently fast that particle size is not a major issue.

[0177] General experimental details regarding the leaching of gold ore in ethyl acetate, acetic acid, or acetonitrile: A method flowchart for Method 300, which involves leaching in a water-miscible or partially water-miscible organic solvent, such as ethyl acetate, acetic acid, or acetonitrile, is shown in Figure 4. This technique is useful for highly efficient gold leaching, for example, by using low concentrations of HCl and H2O2 in ethyl acetate, acetic acid, or acetonitrile instead of water. In Method 300, crushed and polished gold ore 302 was subjected to the leaching step 304 by adding it to a water-miscible or partially water-miscible organic solvent, such as ethyl acetate, acetic acid, or acetonitrile having a concentration of 1 M HCl and 0.1 M H2O2306. The resulting mixture was stirred for 4 hours. The ethyl acetate or acetonitrile was separated from the solid residue 312, and then a solution of gold (HAuCl4)310 dissolved in ethyl acetate, acetic acid, or CH3CN was obtained by evaporation under vacuum. Next, the resulting precipitate was dissolved in 0.1 M HCl, and gold was extracted by solvent extraction process 316 using I(a)(i) in DCM, and finally stripped with H2SO4 (1 M) containing 0.7 M thiourea. 49For example, the gold content obtained was determined by AAS, which exhibits a gold recovery efficiency of 99%. After stripping, the organic phase can be reduced to obtain 318 pure gold 320. In an alternative route, a solution of dissolved gold (HAuCl4) 310 in ethyl acetate, acetic acid, or CH3CN is reduced with an agent, such as NaBH4, ferrocene, Fe powder, or Zn powder 322. Using a process including such a reduction step 322 instead of the above process including an evaporation step 314 may offer certain advantages, for example, because evaporating the solvent incurs additional costs, such as energy and high temperatures required for evaporating the solvent. By reducing the gold with one of the above-mentioned reducing agents, the evaporation step 314 can be omitted, and the solvent can be reused directly. The gold obtained after the reduction step 322 can then be subjected to a solvent extraction process 324 using, for example, I(a)(i) in DCM, and stripped with 1M H2SO4 containing 0.7M thiourea (not shown). After stripping, the organic phase is reduced to obtain 326, pure gold 328. The ethyl acetate, acetic acid, or CH3CN removed after the reduction step 322 can be reused for use in the leaching step 304 330. The solvent extraction step (316, 324) in method 300 is useful for removing impurities such as copper, which can be reduced together with the gold. Such a solvent extraction step (316, 324) may include a conventional leaching and solvent extraction step (i.e., leaching in aqua regia), or it may include a method for leaching and extracting gold from a gold-containing material in one step, as described herein, for example.

[0178] Exemplary experimental details on the leaching of gold ore in ethyl acetate, acetic acid, or acetonitrile: 5.0 g of crushed and polished gold ore with an average particle size of 74 micrometers was added to 5 ml of ethyl acetate, acetic acid, or acetonitrile containing 30% w / w ethyl acetate, acetic acid, or acetonitrile with 350 mg of concentrated HCl and 200 mg of H2O2. The resulting mixture was stirred for 4 hours. The ethyl acetate, acetic acid, or acetonitrile was separated from the solid residue and evaporated under vacuum. The resulting precipitate was then dissolved in 2 ml of 0.1 M HCl, and gold was extracted by a solvent extraction process using 27.2 mg of I(a)(i) in 2 ml of DCM, and finally stripped with 2 ml of 1 M H2SO4 containing 0.7 M thiourea. The resulting gold content was determined by AAS, which shows a gold recovery efficiency of 96-97%.

[0179] Example 4: Reduction of leached gold in different organic solvents For each test, 5 ml of organic solvent containing different amounts of gold as shown in Table 8 (containing 0.5 g of 37% HCl, i.e., the molar concentration of HCl in the organic solvent was 1 M) was treated with the indicated reducing agent for 10 minutes. In the case of Fe powder, the stirring time was 2 hours. The concentration of the gold solution was measured by AAS.

[0180] Example 5: Dissolution of palladium in an organic solvent A mixture of hydrochloric acid and hydrogen peroxide was selected as a leaching agent in different water-miscible or partially water-miscible organic solvents (ethyl acetate, acetic acid, or acetonitrile). At room temperature, 5.0 mg of palladium powder (200 mesh) was added to a stirred mixture of 5 ml of organic solvent (ethyl acetate, acetic acid, or acetonitrile) containing 500 mg of concentrated HCl (37% w / w) and 60 mg of H2O2 (30% w / w). After 15 minutes, the palladium powder was completely dissolved, yielding a clear red solution.

[0181] Example 6: Dissolution of platinum in an organic solvent 5 mg of platinum powder (200 mesh) was added at room temperature to a stirred organic solvent (ethyl acetate, acetic acid, or acetonitrile) containing 500 mg of concentrated HCl (37% w / w) and 60 mg of H2O2 (30% w / w). After 90 minutes, the platinum powder was completely dissolved, yielding a pale yellow solution.

[0182] Example 7: Effect of adding halide salt to an acid mixture (a) Measurement of the rate of gold dissolution 120 mg (0.610 mmol) of 99.9% gold wire with a diameter of 0.25 mm was placed in 20 ml of acetic acid containing the desired amount of acid, oxidant, and optionally CaCl2, and stirred at 800 rpm (stirring plate setting) for various times (10-60 minutes) at various temperatures. The remaining gold wire was then removed from the reaction mixture, washed with acetone, and air-dried. The remaining wire was then weighed to calculate the amount of gold dissolved. The dissolution rate was then determined based on the wire diameter, mass change rate, and dissolution time. Table 9 shows the rates of gold dissolution under varying conditions at room temperature. Figure 5 shows a comparison of gold dissolution rates in aqua regia, concentrated HCl / H2O2, and acetic acid systems. The reagent concentrations in acetic acid were HCl (1.5 M), H2O2 (0.6 M), and CaCl2 (0.6 M). A new HCl / H2O2 mixture was prepared by mixing 4 parts concentrated HCl with 1 part 30% H2O2.

[0183] (b) Processing of gold ore 5.00 g of gold ore was added to a desired amount of acetic acid (5.0 ml or 10.0 ml) containing HCl, H2O2, and CaCl2. The resulting mixture was stirred at 800 rpm for various durations. The acetic acid was separated from the solid residue by centrifugation (1 minute) and evaporated under vacuum. The resulting residue was then dissolved in 2.0 ml of 1 M HCl, and its gold content was determined by ICP-OES (Table 10).

[0184] (c) Selective gold from printed circuit boards leaching 20 g of printed circuit board (PCB) was added to 100 ml of acetic acid solution containing 0.5 M HCl, 0.2 M CaCl2, and 0.2 M H2O2 without crushing, and stirred for 2 minutes. The treated pieces were separated, washed with water, and then treated with hot aqua regia to see if any gold remained. ICP revealed that over 99% of the gold was leached, but less than 5% of the Ni and 1% of the copper were dissolved. The same solution was reused 75 times to leach gold from fresh PCBs before any loss of activity was observed (i.e., 1.5 kg of PCB was treated with a total of 100 ml of HOAc solution).

[0185] Gold leaching from PCBs using an HOAc system (containing 0.5 M HCl, 0.2 M H2O2, and 0.2 M CaCl2) for less than 20 seconds at room temperature resulted in selective gold dissolution (i.e., underlying nickel was still present).

[0186] (d) Results and discussion This specification discloses a novel gold leaching system having the highest gold dissolution rate to date. This system uses acetic acid as a solvent and contains very low concentrations of additional acids and oxidants. In addition to its unsuitable gold dissolution rate, this novel leaching system is also highly selective for gold over base metals, allowing gold to dissolve even faster than iron, nickel, cobalt, and copper. The efficiency of this novel leaching system was tested with gold ore, jewelry scrap, and electronic waste (scrap), yielding over 99% gold leaching at room temperature in just 25 minutes, 10 minutes, and 10-20 seconds, respectively.

[0187] At room temperature, 6020 gm of gold -2 h -1 The gold dissolution rate (three times faster than that of aqua regia) was obtained by using acetic acid as the solvent under mild conditions (Tables 9 and 11). This result represents the fastest recorded rate of gold dissolution known in either an organic or aqueous solution system (significantly faster than other known systems). By heating the system to 60°C, the gold dissolution rate was increased to 9000 gm³. -2 h-1 This further increases the effect (Table 11).

[0188] As can be seen from items 13 and 14 in Table 11, by using acetic acid as the solvent for dissolution, the gold dissolution rate obtained for the comparative system using water as the solvent was (5.1 gm). -2 h -1 Compared to that, the gold dissolution rate is dramatically higher (6020 gm -2 h -1 ) brought about.

[0189] In addition to its substantially rapid dissolution rate, this novel leaching method exhibits a very high affinity for gold over base metals compared to concentrated HCl / H2O2 and aqua regia systems, resulting in gold dissolving faster than most base metals (Figure 6).

[0190] This selectivity leads to reduced reagent consumption, contributing to making this extraction technique more economical than both aqua regia and concentrated HCl / H2O2.

[0191] This acetic acid process is not only the fastest known gold dissolution system, but is also, for example, easy to implement, energy-efficient, and safer than aqua regia or cyanide systems. Being reusable, the acetic acid system generates minimal liquid waste compared to other systems, and furthermore, eliminates the requirement for enormous water consumption compared to cyanide processes, which could lead to widespread applications of this novel technology in remote gold mines without access to water sources. Table 11 compares the efficiency of this extraction method to the gold dissolution rates of reported leaching systems. The acetic acid process is substantially more efficient than reported leaching methods while maintaining mild operating conditions. The fast reaction rate of the novel leaching system, along with low reagent consumption, simple chemical action, ambient temperature handling, and the use of commercially available and more environmentally friendly reagents, makes this novel leaching system suitable for large-scale operations of gold extraction from all gold-containing materials.

[0192] Although this application is described with reference to examples, it should be understood that the scope of the claims should not be limited by the embodiments described in the examples, but should be given the broadest possible interpretation consistent with the overall description. In connection with the present invention, the following is further disclosed. [1] A method for leaching gold, palladium, and / or platinum from a substance containing gold, palladium, and / or platinum, wherein the substance (a) Acid, (b) Oxidizing agents, and (c) Water-miscible or partially water-miscible organic solvents A method comprising contacting a mixture containing the substance with conditions for leaching the gold, palladium, and / or platinum from the substance. [2] The method described above is Separating the water-miscible or partially water-miscible organic solvent containing the leached gold, palladium, and / or platinum from insoluble impurities, The method according to [1], further comprising evaporating the water-miscible or partially water-miscible organic solvent from the leached gold, palladium, and / or platinum. [3] The above method, after evaporation, uses a compound of formula I to obtain the leached gold, palladium, and / or platinum. [ka] During the ceremony, R 1 -NR 4 R 5 or aryl, R 2 and R 3 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 2 and R 3 Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C 1-4 Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, R 4 and R 5 These are H and C, which are independent of each other.1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 Selected from cycloalkyl, heterocycloalkyl, and aryl, or R 4 and R 5 Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C 1-4 Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, X is either O or S, Y is S, NR 6 , or CR 6 R 7 And, R 6 and R 7 These are H and C, which are independent of each other. 1-10 Alkyl, C 3-10 Cycloalkyl, C 1-6 Alkilen C 3-10 The method according to [2], further comprising treating a compound selected from cycloalkyl, heterocycloalkyl, and aryl under conditions for forming a complex between the compound of formula I and the leached gold and / or palladium. [4] The compound of formula I is the compound of formula I(a),

change

[10] R 6 However, H, C 1-6 Alkyl, or C 3-8 The method according to [9], wherein the material is cycloalkyl.

[11] The method according to [3], wherein the compound of formula I is a compound of formula I(a)(i), I(a)(ii), I(a)(iii), or I(a)(iv).

change

[12] The method according to

[11] , wherein the compound of formula I is the compound of formula I(a)(i).

change

[13] The method according to [3], wherein the compound of formula I is the compound of formula I(b)(i).

change

[14] The method according to any one of [3] to

[13] , wherein the conditions for forming the complex between the compound of formula I and the leached gold and / or palladium include treating the leached gold, palladium and / or platinum in a non-aqueous miscible organic solvent with the compound of formula I for a period of time from about 2 minutes to about 30 minutes at a temperature of about 10°C to about 40°C.

[15] The method according to

[14] , wherein the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene.

[16] The method according to any one of [3] to

[15] , further comprising stripping the gold and / or palladium from the complex between the compound of formula I and the leached gold and / or palladium by treating the non-aqueous miscible organic solvent containing the complex between the compound of formula I and the leached gold and / or palladium with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase containing the compound of formula I.

[17] The method according to

[16] , further comprising: separating the gold and / or palladium-containing strip solution from the gold and / or palladium-reduced organic phase containing the compound of formula I; and recovering gold and / or palladium from the gold and / or palladium-containing strip solution by electrolytic extraction or reduction.

[18] The method described above is Separating the water-miscible or partially water-miscible organic solvent containing the leached gold, palladium, and / or platinum from insoluble impurities, Under conditions for obtaining gold, palladium, and / or platinum, the leached gold, palladium, and / or platinum in a water-miscible or partially water-miscible organic solvent is treated with a reducing agent, The method according to [1], further comprising separating the gold, palladium, and / or platinum from the water-miscible or partially water-miscible organic solvent.

[19] The reducing agent is NaBH 4 The method according to

[18] , selected from ferrocene, Fe powder, and Zn powder.

[20] The method according to

[18] or

[19] , further comprising reusing a water-miscible or partially water-miscible organic solvent.

[21] The method, after separating the gold, palladium, and / or platinum from the water-miscible or partially water-miscible organic solvent, is performed under conditions for forming a complex between the compound of formula I and the dissolved gold and / or palladium. Dissolving the aforementioned gold, palladium, and / or platinum in aqua regia, The method according to any one of

[18] to

[20] , further comprising treating the dissolved gold, palladium, and / or platinum with a compound of formula I as described in any one of [3] to

[13] .

[22] The method according to

[21] , wherein the conditions for forming the complex between the compound of formula I and the dissolved gold and / or palladium include treating the dissolved gold, palladium and / or platinum in a non-aqueous miscible organic solvent with the compound of formula I for a period of time from about 2 minutes to about 30 minutes at a temperature of about 10°C to about 40°C.

[23] The method according to

[22] , wherein the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene.

[24] The method according to any one of

[21] to

[23] , further comprising stripping the gold and / or palladium from the complex between the compound of formula I and the leached gold and / or palladium by treating the non-aqueous miscible organic solvent containing the complex between the compound of formula I and the dissolved gold and / or palladium with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold and / or palladium-containing strip solution and a gold and / or palladium-reduced organic phase containing the compound of formula I.

[25] The method according to

[24] , further comprising: separating the gold and / or palladium-containing strip solution from the gold and / or palladium-reduced organic phase containing the compound of formula I; and recovering gold and / or palladium from the gold and / or palladium-containing strip solution by electrolytic extraction or reduction.

[26] The method according to any one of [1] to

[25] , wherein the conditions for leaching the gold, palladium, and / or platinum from the gold, palladium, and / or platinum-containing material include stirring the gold, palladium, and / or platinum-containing material and the mixture at a temperature of about 10°C to about 80°C for about 0.1 minutes to about 30 minutes.

[27] The method according to any one of [1] to

[26] , wherein the acid in the mixture is an aqueous solution of HCl having a concentration of about 0.01 M to about 2.5 M.

[28] The acid in the mixture is HCl, H 2 SO 4 HBr, HNO 3 、H 3 PO 4 The method described in any one of [1] to

[26] , selected from , and HI.

[29] The oxidizing agent in the mixture is H 2 O 2 、Cl 2 、Br 2 、I 2 Ca(ClO) 2 HNO 3 , MnO 2 , KMnO 4 , and K 2 Cr 2 O 7 A method described in any one of the items [1] to

[28] , selected from the above.

[30] The oxidizing agent is H 2 O 2 The method described in

[29] .

[31] The oxidizing agent is Ca(ClO) 2 The method described in

[29] .

[32] The method according to any one of [1] to

[31] , wherein the water-miscible or partially water-miscible organic solvent in the mixture is selected from acetic acid, ethyl acetate, and acetonitrile.

[33] The method according to any one of [1] to

[32] , wherein the mixture further comprises a metal halide, an ammonium halide, a tetraalkylammonium halide, or a combination thereof.

[34] The mixture further comprises the metal halide, wherein the metal halide is CaCl 2 The method described in

[33] .

[35] The CaCl in the mixture 2 The method according to

[34] , wherein the concentration is approximately 0.05 M to approximately 1.5 M.

[36] Reagent (a) in the mixture is HCl, and reagent (b) in the mixture is H 2 O 2 The method according to

[34] or

[35] , wherein reagent (c) in the mixture is acetic acid.

[37] The method according to any one of [1] to

[36] , wherein the substance containing gold, palladium, and / or platinum is a gold-containing substance.

[38] The method according to

[37] , wherein the gold-containing substance is a gold-containing ore.

[39] The method according to

[37] , wherein the gold-containing material further comprises iron, copper, cobalt, or nickel, or a combination thereof, and the method selectively dissolves the gold from the gold-containing material.

[40] The above method is at least 500 gm -2 h -1 The method according to any one of [1] to

[39] , which provides a gold dissolution rate.

[41] The above method provides at least 1000 gm -2 h -1 The method according to any one of [1] to

[39] , which provides a gold dissolution rate.

[42] The above method is at least 5000 gm -2 h -1 The method according to any one of [1] to

[39] , which provides a gold dissolution rate.

[43] The above method involves approximately 500 gm -2 h -1 ~About 9500gm -2 h -1 The method according to any one of [1] to

[39] , which provides a gold dissolution rate.

[44] The above method involves approximately 1000 gm -2 h -1 ~About 9500gm -2 h -1 The method according to any one of [1] to

[39] , which provides a gold dissolution rate.

[45] The method according to any one of [1] to

[36] , wherein the substance comprising gold, palladium, and / or platinum is a platinum group metal concentrate.

[0193] All publications, patents, and patent applications are incorporated herein by reference to the same extent as if each individual publication, patent, or patent application were specifically and individually indicated as being incorporated by reference in its entirety. If any term in this application is found to be defined differently in any document incorporated herein by reference, the definition provided herein should function as the definition of the term. 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S. J., Hydrometallurgy, 2006, 82, 126-132. 26 Kazakov, V. P.; Lapshin, A. I.; Peshchevitskii, B. I. Russ. J. Inorg. Chem. 1964, 9, 708. 27 Plaskin,INand Kozhukhova,MA,Sbornik Nauchnyhk Trudov,Institut Tsvetnykh Metallov,1960,33,107-119. 28 Preisler, PW and Berger, L., Journal of the American Chemical Society, 1947, 69, 322-325. 29 Schulze,RG,1984,Journal of Metals,1984,36,62-65. 30 Groenewald, T., Hydrometallurgy, 1976, 1, 277-290. 31 Gonen, N., Hydrometallurgy, 2003, 69, 169-176. 32 Krzewska, S. and Podsiadly, H., Journal of Inorganic and Nuclear Chemistry, 1980, 42, 83-86. 33 Orgul, S., Atalay, U. Hydrometallurgy, 2002, 67, 71-77. 34J.W.Mellor,A Comprehensive Treatise of Inorganic and Theoretical Chemistry(London:Longman Green & Co.,1923),p.499. 35 F.Habashi,Principles of Extractive Metallurgy,Vol.2 nd ed.(New York:Gordon and Breach,1980),p.39. 36 Finkelstein,N.P.,Hoare,R.M.,James,G.S.,Howat,D.D.,Journal of the South African Institute of Mining and Metallurgy,1996,67,196-215. 37 Filmer,A.O.,Lawrence,P.R.,Hoffman,W.,1984.A comparison of cyanide,thiourea,and chlorine as lixiviants for gold.Gold-Mining,Metallurgy,and Geology.Australasian Institute of Mining and Metallurgy,Melbourne,pp.279-287. 38 Ikiz,D.,Gulfen,M.,Aydin,A.O.Minerals Engineering,2006,19,972-974. 39 Jeffrey,M.I.,Breuer,P.L.,Choo,W.L.Metall.Mater.Trans.2001,B 32,979-986. 40 Nesbitt,C.C.,Milosavljevic,E.B.,Hendrix,J.L.,Chem.Res.1990,29,1696-1700. 41Ghobeiti Hasab,M.,Rashchi,F.,Raygan,Sh.Miner.Eng.2013,50-51,140-142. 42 Ghobeiti Hasab,M.,Raygan,Sh.,Rashchi,F.,Hydrometallurgy,2013,138,59-64. 43 Cheng,Y.Shen,S.Zhang,J.Chen,S.Xiong,L.Liu J.Ind.Eng.Chem.Res.2013,52,16622-16629. 44 Parker,AJMuir,DJSmart,YCAvraamides,J.Hydrometallurgy,1981,7,213-233. 45 Yoshimura,A.Takai,M.Matsuno,Y.Hydrometallurgy,2014,149,177-182. 46 Gill,JBGoodall,DCJeffreys,B.Hydrometallurgy,1984,13,221-226. 47 Lin,W.Zhang,RWJang,SSWong,CPhong,J.Angew.Chem.Int.Ed.2010,49,7929-7932. 48 Yukimichi,NJChem.Soc.,Chem.Commun.1992,426-427. 49 Moradi,L.Salimi,H.Piltan,M.Yavari,I.United States Patent.Pub.No.US 2012 / 0228151 A1. Sep.13,2012. 50 Vest,P.Schuster,M.Konig,KHFresenius J Anal Chem.1991,341,556-568. 51Jeffrey,M.Breuer,P.L.Chu,C.K.Int.J.Miner.Process.2003,72,323-330. 52 Oraby,E.A.& Eksteen,J.J.The leaching of gold,silver and their alloys in alkaline glycine-peroxide solutions and their adsorption on carbon.Hydrometallurgy 152,199-203(2015). 53 Geoffroy,N.& Cardarelli,F.A method for leaching or dissolving gold from ores or precious metal scrap.JOM.57,47-50(2005). 54 Senanayake,G.Gold leaching in non-cyanide lixiviant systems:critical issues on fundamentals and applications.Miner.Eng.17,785-801(2004). 55 Li,J.et al.Thiocyanate hydrometallurgy for the recovery of gold.Part II:the leaching kinetics.Hydrometallurgy 113-114,10-189(2012). 56 Li,J.& Miller,J.D.A review of gold leaching in acid thiourea solutions.Miner.Process.Extr.Metall.Rev.27,177-214(2006). 57Lin, W., Zhang, R. W., Jang, S. S., Wong, C. P. & Hong, J. I. “Organic aqua regia”-powerful liquids for dissolving noble metals. Angew. Chem. Int. 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Claims

1. A method for leaching gold from electronic waste containing gold, wherein the electronic waste is (a) Acid, (b) Oxidizing agents, and (c) A water-miscible or partially water-miscible organic solvent selected from acetic acid, ethyl acetate, acetonitrile, and tetrahydrofuran. The method comprising contacting a mixture containing the above under conditions for leaching the gold from the electronic waste.

2. The method according to claim 1, wherein the mixture further comprises (d) a metal halide, an ammonium halide, a tetraalkylammonium halide, or a combination thereof.

3. The mixture may contain NaCl, KCl, NaBr, KBr, NaI, KI, CaCl ２ MgCl ２ NH ４ Br, NH ４ Cl, and N(CH ３ ) ４ The method according to claim 1 or 2, further comprising Cl, or a combination thereof.

4. The method according to claim 2 or 3, wherein the mixture further comprises a metal halide.

5. Metal halide is CaCl ２ The method according to any one of claims 2 to 4.

6. The aforementioned CaCl ２ The method according to claim 5, wherein the substance is present in the mixture at a concentration of 0.05 M to 1.5 M.

7. The method according to any one of claims 1 to 6, wherein the acid in the mixture is a hydrogen halide, chlorous acid, chloric acid, bromic acid, bromate, iodic acid, iodic acid, perchloric acid, sulfuric acid, nitric acid, oxalic acid, phosphoric acid, organic acid, or a combination thereof.

8. The acid in the mixture is selected from HCl, H ２ SO ４ , HBr, HNO ３ , H ３ PO ４ , and HI, and the method according to any one of claims 1 to 7.

9. The acid in the mixture is HCl, H ２ SO ４ HBr, H ３ PO ４ The method according to any one of claims 1 to 8, selected from , and HI.

10. The method according to any one of claims 1 to 9, wherein the acid is HCl.

11. The method according to claim 10, wherein the HCl is present in the mixture at a concentration of 0.01 M to 2.5 M.

12. The oxidizing agent in the mixture is ozone, nitric acid, hydrogen peroxide, O ２ , bubble air, I ２ , Br ２ , Cl ２ The method according to any one of claims 1 to 11, wherein the material is potassium monopersulfate, ammonium polyatomic salt, calcium hypochlorite, sodium polyatomic salt, potassium polyatomic salt, manganese oxide, tetraalkylammonium salt, peroxomonosulfate, urea, peracetic acid, alkanesulfonic acid, aromatic sulfonic acid, or a combination thereof.

13. The oxidizing agent in the mixture is a sodium polyatomic salt, NH ４ ClO ３ H ２ O ２ , Cl ２ , Br ２ , I ２ Ca(ClO) ２ HNO ３ MnO ２ , KMnO ４ , and K ２ Cr ２ O ７ The method according to any one of claims 1 to 12, selected from the following.

14. The oxidizing agent is a sodium polyatomic salt, NH ４ ClO ３ H ２ O ２ , or Ca(ClO) ２ The method according to any one of claims 1 to 13.

15. The oxidizing agent is H ２ O ２ The method according to any one of claims 1 to 14.

16. The aforementioned H ２ O ２ The method according to claim 15, wherein the substance is present in the mixture at a concentration of 0.01 M to 1.0 M.

17. The method according to any one of claims 1 to 16, wherein the water-miscible or partially water-miscible organic solvent is selected from acetic acid, ethyl acetate, and acetonitrile.

18. The method according to any one of claims 1 to 17, wherein the water-miscible or partially water-miscible organic solvent is acetic acid.

19. The method according to any one of claims 1 to 18, wherein the conditions for leaching the gold from the electronic waste include stirring the electronic waste and the mixture at a temperature of 20°C to 60°C for 0.1 minutes to 4 hours.

20. The method according to any one of claims 1 to 19, wherein the conditions for leaching the gold from the electronic waste include stirring the electronic waste and the mixture at a temperature of 20°C to 60°C for 0.1 minutes to 2 hours.

21. The method according to any one of claims 1 to 20, wherein the conditions for leaching the gold from the electronic waste include stirring the electronic waste and the mixture at a temperature of 20°C to 40°C.

22. The method according to any one of claims 1 to 21, wherein the conditions for leaching the gold from the electronic waste include stirring the electronic waste and the mixture at a temperature of 20°C to 25°C.

23. Reagent (a) in the mixture is HCl, and reagent (b) in the mixture is H ２ O ２ The reagent (d) in the mixture is CaCl ２ The method according to any one of claims 1 to 22, wherein the water-miscible or partially water-miscible organic solvent (c) is acetic acid.

24. The method described above is To separate the water-miscible or partially water-miscible organic solvent containing the leached gold from insoluble impurities, The method according to any one of claims 1 to 23, further comprising evaporating the water-miscible or partially water-miscible organic solvent from the leached gold.

25. The method described above is To separate the water-miscible or partially water-miscible organic solvent containing the leached gold from insoluble impurities, Under conditions for obtaining gold, the leached gold in the water-miscible or partially water-miscible organic solvent is treated with a reducing agent, The method according to any one of claims 1 to 24, further comprising separating the gold from the water-miscible or partially water-miscible organic solvent.

26. The reducing agent is NaBH ４ The method according to claim 25, selected from ferrocene, Fe powder, and Zn powder.

27. The method according to claim 25 or 26, further comprising reusing a water-miscible or partially water-miscible organic solvent.

28. The method according to any one of claims 1 to 27, wherein the electronic waste further comprises iron, copper, cobalt, or nickel, or a combination thereof, and the method selectively dissolves the gold from the electronic waste.

29. The above method, after evaporation, uses a compound of formula I to remove the leached gold. 【Chemistry 1】 During the ceremony, R １ -NR ４ R ５ or aryl, R ２ and R ３ These are H and C, which are independent of each other. １－１０ Alkyl, C ３－１０ Cycloalkyl, C １－６ Alkilen C ３－１０ Selected from cycloalkyl, heterocycloalkyl, and aryl, or R ２ and R ３ Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C １－４ Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, R ４ and R ５ These are H and C, which are independent of each other. １－１０ Alkyl, C ３－１０ Cycloalkyl, C １－６ Alkilen C ３－１０ Selected from cycloalkyl, heterocycloalkyl, and aryl, or R ４ and R ５ Together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or heteroaryl group, or one or more carbon atoms, C １－４ Forming heterocycloalkyl or heteroaryl groups substituted with alkyl groups, X is either O or S, Y is S, NR ６ , or CR ６ R ７ And, R ６ and R ７ These are H and C, which are independent of each other. １－１０ Alkyl, C ３－１０ Cycloalkyl, C １－６ Alkilen C ３－１０ The method according to any one of claims 1 to 28, further comprising treating a compound selected from cycloalkyl, heterocycloalkyl, and aryl under conditions for forming a complex between the compound of formula I and the leached gold.

30. The compound of formula I is the compound of formula I(a), 【Chemistry 2】 In the formula, R ２ , R ３ , R ４ , R ５ The method according to claim 29, wherein Y is as described in claim 29.

31. R ２ , R ３ , R ４ , and R ５ The method according to claim 30, wherein only one of them is H.

32. R ２ and R ３ However, together with the nitrogen atom to which they are bonded, they form a heterocycloalkyl or substituted heterocycloalkyl, and the heterocycloalkyl is azilidinyl, azetidinyl, pyrrolidinyl, piperidinyl, azepanil, azokanil, imidazolidinyl, oxazolidinyl, thiazolidinyl, piperazinyl, hexahydropyrimidinyl, morpholinyl, 1,3-oxazinanyl, thiomorpholinyl, 1,3-thiadinyl The method according to claim 30, selected from 1,3-diazepanyl, 1,3-oxazepanyl, 1,3-thiazepanyl, 1,4-diazepanyl, 1,4-oxazepanyl, 1,4-thiazepanyl, 1,3-diazocanyl, 1,3-oxazocanyl, 1,3-thiazocanyl, 1,4-diazocanyl, 1,4-oxazocanyl, 1,4-thiazocanyl, 1,5-diazocanyl, 1,5-oxazocanyl, and 1,5-thiazocanyl.

33. R ２ and R ３ The method according to claim 30, wherein, together with the nitrogen atom to which they are attached, they form morpholinyl, pyrrolidinyl, or 4-methylpiperidinyl.

34. R ４ H is R ５ C １－６ Alkyl or C ３－８ The method according to claim 30, wherein the material is cycloalkyl.

35. Y is NR ６ The method according to claim 29.

36. R ６ is H, C １－６ alkyl, or C ３－８ cycloalkyl, the method according to claim 35.

37. The method according to claim 29, wherein the compound of formula I is a compound of formula I(a)(i), I(a)(ii), I(a)(iii), or I(a)(iv). 【Transformation 3】

38. The method according to claim 37, wherein the compound of formula I is the compound of formula I(a)(i). 【Chemistry 4】

39. The method according to claim 29, wherein the compound of formula I is the compound of formula I(b)(i). 【Transformation 5】

40. The method according to claim 29, wherein the conditions for forming the complex between the compound of formula I and the leached gold include treating the leached gold in a non-aqueous miscible organic solvent with the compound of formula I at a temperature of 10°C to 40°C for a period of 2 to 30 minutes.

41. The method according to claim 40, wherein the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene.

42. The method according to claim 40, further comprising stripping the gold from the complex between the compound of formula I and the leached gold by treating the non-aqueous miscible organic solvent containing the complex between the compound of formula I and the leached gold with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold-containing strip solution and a gold-reduced organic phase containing the compound of formula I.

43. The method according to claim 42, further comprising: separating the gold-containing strip solution from the gold-reducing organic phase containing the compound of formula I; and recovering gold from the gold-containing strip solution by electrolysis or reduction.

44. The method, after separating the gold from the water-miscible or partially water-miscible organic solvent, is performed under conditions for forming a complex between the compound of formula I described in any one of claims 29 to 39 and the dissolved gold. Dissolving the aforementioned gold in aqua regia, The method according to claim 25 or 26, further comprising treating the dissolved gold with a compound of formula I described in any one of claims 29 to 39.

45. The method according to claim 44, wherein the conditions for forming the complex between the compound of formula I and the dissolved gold include treating the dissolved gold in a non-aqueous miscible organic solvent with the compound of formula I at a temperature of 10°C to 40°C for a period of 2 to 30 minutes.

46. The method according to claim 45, wherein the non-aqueous miscible organic solvent is dichloromethane, chloroform, chlorobenzene, or toluene.

47. The method according to claim 45 or 46, further comprising stripping the gold from the complex between the compound of formula I and the leached gold by treating the non-aqueous miscible organic solvent containing the complex between the compound of formula I and the dissolved gold with an aqueous solution containing an acid and thiourea, under conditions for obtaining a gold-containing strip solution and a gold-reduced organic phase containing the compound of formula I.

48. The method according to claim 47, further comprising: separating the gold-containing strip solution from the gold-reducing organic phase containing the compound of formula I; and recovering gold from the gold-containing strip solution by electrolytic extraction or reduction.

49. The above method provides at least 500 gm －２ h －１ The method according to any one of claims 1 to 48, which provides a gold dissolution rate.

50. The above method provides at least 1000 gm －２ h －１ The method according to any one of claims 1 to 48, which provides a gold dissolution rate.

51. The above method provides at least 5000 gm －２ h －１ The method according to any one of claims 1 to 48, which provides a gold dissolution rate.

52. The above method is 500 gm －２ h －１ ~9500gm －２ h －１ The method according to any one of claims 1 to 48, which provides a gold dissolution rate.

53. The above method is 1000 gm －２ h －１ ~9500gm －２ h －１ The method according to any one of claims 1 to 47, which provides a gold dissolution rate.

54. The method according to any one of claims 1 to 53, wherein the electronic waste includes a printed circuit board.

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