Method for cyanide-free gold immersion by halogen oxyacid salt in cooperation with 3-bromopropionic acid

Abstract

The application discloses a halogen oxyacid salt cooperates with 3-bromopropionic acid to realize cyanide-free gold leaching method and belongs to the technical field of hydrometallurgy. The method comprises the following steps: sequentially performing drying, fine grinding and oxidation roasting treatment on a gold ore, then mixing the obtained roasting sand with a leaching solution composed of halogen oxyacid salt and 3-bromopropionic acid to prepare a slurry, and performing stirring leaching under normal temperature and pressure. The method uses the halogen oxyacid salt as an oxidizing agent and the 3-bromopropionic acid as a complexing agent to realize efficient dissolution of gold in the roasting sand of a high-sulfur and high-arsenic gold ore under mild conditions, the gold leaching rate can be up to 86.97%, the leaching speed is fast, and the process flow is short. The whole leaching process does not use cyanide, is environment-friendly, has low reagent toxicity, and is especially suitable for cyanide-free leaching and industrial application of high-sulfur and high-arsenic complex and difficult-to-treat gold ores.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgy, specifically to a method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid. Background Technology

[0002] Gold, due to its extremely high chemical stability, plays an irreplaceable role in strategic fields such as financial reserves, electronic information, aerospace, and medical devices. However, with the increasing scarcity of easily processed gold ore resources, my country's gold mining is facing severe challenges of resource depletion and complex composition. For refractory gold ores with high sulfur and high arsenic content, gold particles are often deeply encapsulated in a sulfide or arsenide matrix, making it difficult for conventional processes to achieve efficient gold stripping and recovery. This has become a key technological bottleneck restricting the industry's development.

[0003] To replace traditional cyanide processes, the industry has extensively explored various cyanide-free gold leaching pathways, including thiourea, thiosulfate, halogen, and bioleaching. However, these methods still generally have technical limitations in practical industrial applications. For example, the thiourea system is prone to oxidative decomposition under high-intensity operating conditions, resulting in high reagent consumption; most non-cyanide reagents exhibit slow leaching kinetics or poor universality when faced with fluctuations in ore composition; furthermore, while some alternative reagents have reduced toxicity, they bring new challenges to subsequent advanced wastewater treatment and resource recovery, making it difficult to achieve the expected balance between economic benefits and environmental friendliness.

[0004] Therefore, the gold smelting industry urgently needs to construct an ideal non-cyanide technology system with high leaching efficiency, mild reaction conditions, and controllable environmental risks. Developing a potassium iodate-3-bromopropionic acid leaching method that combines strong adaptability and green characteristics is of significant practical value for breaking the deadlock in recovering difficult-to-process gold ores and promoting the industry's green transformation. Summary of the Invention

[0005] To overcome the high environmental toxicity barrier of cyanidation processes in complex gold ore smelting and the insufficient extraction performance of existing non-cyanide gold leaching systems, this invention provides a cyanide-free gold leaching method using halogen oxyacid salts in conjunction with 3-bromopropionic acid. This method first pre-treats the gold ore through roasting oxidation, and then uses a leaching system composed of halogen oxyacid salts and 3-bromopropionic acid to leach gold from roasted sand of high-sulfur and high-arsenic gold ore, thereby effectively avoiding the environmental and safety risks associated with cyanidation.

[0006] The above-mentioned technical objective of this invention is achieved through the following technical solution: a method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, comprising the following steps: (1) The gold ore is crushed and ground, and the ground gold ore is roasted and oxidized to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0007] (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) is mixed with a leaching solution composed of halogenated oxyacid salts and 3-bromopropionic acid to form a slurry, and then stirred and leached at room temperature and pressure.

[0008] (3) Perform solid-liquid separation on the slurry after leaching in step (2) to obtain gold-containing filtrate and gold leaching residue.

[0009] Preferably, in step (1), the content of the ore with a fineness of -74µm particle size is 93.52%.

[0010] Preferably, the calcination oxidation pretreatment conditions in step (1) are calcination at 650℃ for 5 hours.

[0011] Preferably, the halogen oxyacid salts mentioned in step (2) are selected from one or more of alkali metal oxyacid salts, alkaline earth metal oxyacid salts or ammonium halogen oxyacid salts.

[0012] More preferably, the halogen oxyacid salt mentioned in step (2) is one or more of potassium iodate, sodium iodate, or potassium bromate, and the concentration of the halogen oxyacid salt is 0.01 to 0.20 mol / L.

[0013] Preferably, the 3-bromopropionic acid in step (2) is added to the leachate in solid or aqueous form, and the concentration in the leachate is 0.01 to 0.40 mol / L.

[0014] Preferably, in step (2), the liquid-solid ratio of the leachate to the high-sulfur, high-arsenic gold ore roasted sand is 4:1 to 9:1, in mL:g.

[0015] Preferably, the pH of the slurry in step (2) is 3 to 8, and sodium hydroxide is generally used to adjust the pH of the reaction system.

[0016] Preferably, the leaching conditions in step (2) are: leaching with stirring for 2 to 24 hours under normal temperature and pressure, and the stirring speed is 250 to 450 rpm.

[0017] The beneficial effects of this invention include: (1) The present invention uses halogenated oxyacid salts and 3-bromopropionic acid as the main components of the leaching system. The system composition is simple and the raw materials are widely available, avoiding the safety and environmental problems caused by the use of highly toxic cyanides in traditional cyanidation processes.

[0018] (2) The leaching system of halogen oxyacid salts and 3-bromopropionic acid constructed in this invention has a synergistic effect of oxidation and complexation. The halogen oxyacid salts, as oxidants, can oxidize gold to Au(I) or Au(III) ions. 3-bromopropionic acid not only provides a suitable acidic environment for the system, but its carboxyl group can also form a stable complex with the oxidized gold ions, reduce the activity of gold ions, inhibit their re-reduction and precipitation, thereby promoting the continuous oxidation and dissolution of gold. At the same time, 3-bromopropionic acid may also improve the wettability of mineral surfaces and the interfacial reaction environment, reduce mineral surface passivation, improve the contact efficiency between halogen oxyacid salts and gold minerals, and further enhance the gold leaching capacity of the system. Therefore, this invention may achieve efficient leaching of gold from roasted sand of high-sulfur and high-arsenic refractory gold ores under normal temperature and pressure conditions through the synergistic effect of oxidation and complexation.

[0019] (3) The leaching process of the present invention is carried out under normal temperature and pressure conditions, without the need for complex equipment such as high temperature and high pressure, which makes the operation simple, the equipment investment low, and easy to achieve large-scale application.

[0020] (4) The method of the present invention has a wide range of applications and has a good leaching effect on gold in roasted sand of difficult-to-process gold ores with high sulfur and high arsenic, which can meet the leaching requirements of complex and difficult-to-process gold ores.

[0021] (5) The leaching system used in this invention does not contain highly toxic chemicals and does not produce harmful gases during the leaching process. It is environmentally friendly and helps to reduce the safety risks and environmental pressure of the gold leaching process. Detailed Implementation

[0022] The following detailed description is based on specific embodiments, but the scope of protection of the present invention is not limited to the content described herein.

[0023] In Examples 1-22 and the comparative examples, the Au grade in the high-sulfur, high-arsenic gold ore roasted sand was 83.11 g / t, and the mass fractions of the other major components Si, Fe, Al, As, S, Mg, Sb, Ca, Pb and Cu were 24.46%, 23.09%, 11.36%, 0.65%, 17.43%, 0.81%, 0.20%, 0.23%, 0.17% and 0.20%, respectively.

[0024] Example 1 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0025] (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 9:1 to obtain a slurry. The pH of the slurry was adjusted to 5 with sodium hydroxide and leached at room temperature for 16 hours with a stirring speed of 350 rpm. After leaching, the slurry was separated into solid and liquid components to obtain gold leaching residue and gold-containing filtrate. The gold content in the gold-containing filtrate was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 78.77%.

[0026] Example 2 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0027] (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) was added to the leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 9:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L and the concentration of 3-bromopropionic acid was 0.2 mol / L). The pH of the slurry was adjusted to 5 with sodium hydroxide. The leaching was carried out at room temperature with stirring for 16 h at a stirring speed of 350 rpm. After the leaching was completed, the slurry was separated into solid and liquid to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 83.51%.

[0028] Example 3 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0029] (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 9:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the slurry was 5. The leaching was carried out at room temperature for 16 hours with stirring at a stirring speed of 350 rpm. After the leaching was completed, the slurry was separated into solid and liquid to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 84.69%.

[0030] Example 4 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0031] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 9:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and the leaching was carried out at room temperature with stirring for 16 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 86.36%.

[0032] Example 5 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0033] (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) was added to the leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide. The leaching was carried out at room temperature with stirring for 16 h at a stirring speed of 350 rpm. After the leaching was completed, the slurry was separated into solid and liquid to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 85.97%.

[0034] Example 6 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0035] (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) was added to the leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide. The leaching was carried out at room temperature for 10 h with stirring at a stirring speed of 350 rpm. After the leaching was completed, the slurry was separated into solid and liquid to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 86.12%.

[0036] Example 7 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0037] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.1 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 300 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 82.54%.

[0038] Example 8 (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting and oxidation pretreatment to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0039] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.2 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 300 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 80.54%.

[0040] Example 9 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0041] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.01 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 300 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 81.54%.

[0042] Example 10 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0043] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.06 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 300 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 85.64%.

[0044] Example 11 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0045] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.4 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 85.05%.

[0046] Example 12 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0047] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 3 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 85.93%.

[0048] Example 13 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0049] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 4 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 85.87%.

[0050] Example 14 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0051] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 8 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 81.26%.

[0052] Example 15 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0053] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 4:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 84.64%.

[0054] Example 16 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0055] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 2 hours at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 80.63%.

[0056] Example 17 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0057] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 4 hours at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 83.81%.

[0058] Example 18 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0059] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 24 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 85.95%.

[0060] Example 19 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0061] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 250 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 83.94%.

[0062] Example 20 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0063] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and the leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 450 rpm. After the leaching was completed, the slurry was subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 82.74%.

[0064] Example 21 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore was crushed and ground to a fineness of -74µm with a particle size of 93.52%. An appropriate amount of the finely ground gold ore was weighed into an evaporating dish, and then the evaporating dish was placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions were roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic carbonaceous gold ore roasted sand.

[0065] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium bromate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium bromate in the leaching solution was 0.06 mol / L and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide. The leaching was carried out at room temperature with stirring for 10 h at a speed of 350 rpm. The leached slurry was then subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was found to be 84.71%.

[0066] Example 22 A method for cyanide-free gold leaching using halogen oxyacid salts in conjunction with 3-bromopropionic acid, the specific steps of which are as follows: (1) The gold ore was crushed and ground to a fineness of -74µm with a particle size of 93.52%. An appropriate amount of the finely ground gold ore was weighed into an evaporating dish, and then the evaporating dish was placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions were roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic carbonaceous gold ore roasted sand.

[0067] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing sodium iodate and 3-bromopropionic acid at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium bromate in the leaching solution was 0.06 mol / L, and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide, and the leaching was carried out by stirring at room temperature for 10 h at a speed of 350 rpm. The leached slurry was then subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was found to be 85.91%.

[0068] Example 23 To further verify the applicability of the halogen oxyacid salt-3-bromopropionic acid non-cyanide gold leaching system described in this invention to different types of gold ores, another high-sulfur, high-arsenic carbonaceous gold ore was selected for testing. Its main chemical composition is as follows: Au grade is 35.2 g / t, and the mass fractions of Cu, Fe, S, As, C, Pb, SiO2, MgO, Al2O3, and CaO are 0.05%, 19.90%, 2.97%, 0.33%, 0.30%, 0.32%, 49.30%, 5.72%, 9.87%, and 6.84%, respectively. The specific steps are as follows: (1) The gold ore was crushed and ground to a fineness of -74µm with a particle size of 93.52%. An appropriate amount of the finely ground gold ore was weighed into an evaporating dish, and then the evaporating dish was placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions were roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic carbonaceous gold ore roasted sand.

[0069] (2) The high-sulfur and high-arsenic carbonaceous gold ore roasted sand obtained in step (1) was added to the leaching solution containing ferricyanide and thioacetamide at a liquid-to-solid ratio (mL:g) of 6:1 (the concentration of potassium iodate in the leaching solution was 0.06 mol / L and the concentration of 3-bromopropionic acid was 0.12 mol / L). The pH of the reaction was adjusted to 6 with sodium hydroxide. The leaching was carried out at room temperature for 10 h with stirring at 350 rpm. The leaching slurry was then subjected to solid-liquid separation to obtain gold leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was found to be 79.96%.

[0070] Comparative Example 1 In contrast, the leachate in this comparative example contained only 3-bromopropionic acid, and the specific steps are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0071] (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) was added to the leaching solution containing 3-bromopropionic acid (the concentration of 3-bromopropionic acid in the leaching solution was 0.12 mol / L) at a liquid-to-solid ratio (mL:g) of 6:1 to obtain a slurry. The pH of the slurry was adjusted to 6 with sodium hydroxide, and the leaching was carried out by stirring at room temperature for 10 h at a stirring speed of 350 rpm. After the leaching was completed, the slurry was separated into solid and liquid to obtain gold leaching residue and gold-containing filtrate. The gold content in the gold-containing filtrate was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 2.83%.

[0072] Comparative Example 2 In contrast, the leachate in this comparative example contains only potassium iodate, and the specific steps are as follows: (1) The gold ore is crushed and ground to control the fineness to -74µm particle size content of 93.52%. A suitable amount of finely ground gold ore is weighed and placed in an evaporating dish. Then the evaporating dish is placed in a muffle furnace for roasting oxidation pretreatment (the treatment conditions are roasting at 650℃ for 5h) to obtain high-sulfur and high-arsenic gold ore roasted sand.

[0073] (2) The high-sulfur, high-arsenic gold ore roasted sand obtained in step (1) was added to a leaching solution containing potassium iodate (the concentration of potassium iodate in the leaching solution was 0.06 mol / L) at a liquid-to-solid ratio (mL:g) of 6:1. The pH of the reaction was adjusted to 6 with sodium hydroxide, and the leaching was carried out at room temperature with stirring for 10 h at a stirring speed of 350 rpm. After leaching, the slurry was subjected to solid-liquid separation to obtain gold-leaching residue and gold-containing filtrate. The gold content was determined by atomic absorption spectrometry, and the gold leaching rate was calculated to be 5.47%.

[0074] The above description is merely a preferred embodiment of the present invention and does not limit the scope of the patent. Any simple modifications, equivalent substitutions, or improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for cyanide-free gold leaching using halogenated oxyacid salts in conjunction with 3-bromopropionic acid, characterized in that, Includes the following steps: (1) The gold ore is crushed and ground, and the ground gold ore is roasted and oxidized to obtain high-sulfur and high-arsenic gold ore roasted sand. (2) The high-sulfur and high-arsenic gold ore roasted sand obtained in step (1) is mixed with a leaching solution composed of halogenated oxyacid salts and 3-bromopropionic acid to form a slurry, and then stirred and leached at room temperature and pressure. (3) Perform solid-liquid separation on the slurry after leaching in step (2) to obtain gold-containing filtrate and gold leaching residue.

2. The method for leaching gold with halogenated oxyacids in conjunction with 3-bromopropionic acid according to claim 1, characterized in that: The conditions for the calcination oxidation pretreatment in step (1) are calcination at 650℃ for 5 hours.

3. The method for leaching gold with halogenated oxyacids in conjunction with 3-bromopropionic acid according to claim 1, characterized in that: In step (1), the content of the ore with a fineness of -74µm particle size was 93.52%.

4. The method for leaching gold with halogenated oxyacid in conjunction with 3-bromopropionic acid according to claim 1, characterized in that: The halogen oxyacid salt mentioned in step (2) is one or more of potassium iodate, sodium iodate, or potassium bromate, and the concentration of the halogen oxyacid salt in the leachate is 0.01 to 0.20 mol / L.

5. The method for leaching gold with halogenated oxyacids in conjunction with 3-bromopropionic acid according to claim 1, characterized in that: In step (2), 3-bromopropionic acid is added to the leachate in solid or aqueous form, and the concentration of 3-bromopropionic acid in the leachate is 0.01 to 0.40 mol / L.

6. The method for leaching gold with halogenated oxyacids in conjunction with 3-bromopropionic acid according to claim 1, characterized in that: In step (2), the liquid-solid ratio of the leachate to the high-sulfur, high-arsenic gold ore roasted sand is 4:1 to 9:1, with units of mL:g.

7. The method for leaching gold with halogenated oxyacids in conjunction with 3-bromopropionic acid according to claim 1, characterized in that: The leaching conditions in step (2) are: leaching with stirring for 2 to 24 hours at normal temperature and pressure, with a stirring speed of 250 to 450 rpm.

8. The method for leaching gold with halogenated oxyacid in conjunction with 3-bromopropionic acid according to claim 1, characterized in that: The pH of the reaction in step (2) is 3 to 8.