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CN-122012927-A - Leaching method for iron oxide-coated gold in calcine

CN122012927ACN 122012927 ACN122012927 ACN 122012927ACN-122012927-A

Abstract

The invention discloses a leaching method for iron oxide coated gold in calcine, which comprises the steps of adding water into calcine to obtain ore pulp, adding an iron leaching agent, regulating a system to be weak acidity, carrying out solid-liquid separation after leaching to obtain iron-removing slag, wherein the iron leaching agent is a mixture of sulfosalicylic acid and sulfosalicylate with a molar ratio of 0.5-1:1-2.5, adding water into the iron-removing slag to prepare ore pulp, regulating the pH value of the ore pulp to be neutral or weak alkaline, adding the gold leaching agent, and carrying out solid-liquid separation after leaching to obtain gold-leaching slag and gold-containing noble liquid. According to the leaching method for the iron oxide coated gold in the calcine, the coated gold in the iron oxide phase can be fully opened, and the gold recovery rate is improved by 15% -20%.

Inventors

  • LIU XIAOLIANG
  • MA YUNCONG
  • CHEN YU
  • SHE ZONGHUA
  • WAN HONGQIANG
  • ZHANG LIFEN
  • TIAN HONGQING
  • NI XIAO

Assignees

  • 长沙矿冶研究院有限责任公司

Dates

Publication Date
20260512
Application Date
20260127

Claims (10)

  1. 1. A leaching method for iron oxide-coated gold in calcine, which is characterized by comprising the following steps: S1, adding water into calcine to obtain ore pulp, adding an iron leaching agent, regulating a system to be weak acid, and carrying out solid-liquid separation after leaching to obtain iron-removing slag, wherein the iron leaching agent is a mixture of sulfosalicylic acid and sulfosalicylate, and the molar ratio of the sulfosalicylic acid to the sulfosalicylate in the mixture is 0.5-1:1-2.5; s2, adding water into the iron-removing slag obtained in the step S1 to prepare ore pulp, adjusting the pH value of the ore pulp to be neutral or weak alkaline, adding a gold leaching agent, and carrying out solid-liquid separation after leaching to obtain gold-leaching slag and gold-containing noble liquid.
  2. 2. The method for leaching iron oxide-coated gold from calcine according to claim 1, wherein in S1, the sulfosalicylate is one or more selected from sodium salt, potassium salt, and ammonium salt.
  3. 3. The method for leaching the iron oxide-coated gold from the calcine according to claim 1, wherein in the step S1, the pH value of the system is adjusted to 2 to 3.5 after the iron leaching agent is added.
  4. 4. The method for leaching iron oxide-coated gold from calcine according to claim 1, wherein in S1, the molar amount of sulfosalicylic acid in the mixture and sulfosalicylate ligands in the sulfosalicylate is 2.5 to 3.5 times the total iron molar amount in the calcine.
  5. 5. The method of leaching iron oxide-coated gold from calcine of claim 4, wherein the sulfosalicylate ligand is one or more of (HOC 6 H 3 (COOH)SO 3 - 、HOC 6 H 3 (COO - )SO 3 - or - OC 6 H 3 (COO - )SO 3 - .
  6. 6. The leaching method for iron oxide-coated gold in calcine according to claim 1, wherein in S1, the liquid-solid ratio of calcine to water is 5-10:1.
  7. 7. The method for leaching the iron oxide-coated gold from the calcine according to claim 1, wherein in the step S1, the leaching temperature is 25-50 ℃, the stirring speed in the leaching process is 200-400 rpm, and the leaching time is 1-3 h.
  8. 8. The method according to claim 1, wherein in S2, the gold leaching agent is a mixture of ferricyanide selected from one or both of sodium ferricyanide and potassium ferricyanide and thiosulfate selected from one or both of sodium thiosulfate and potassium thiosulfate.
  9. 9. The leaching method for iron oxide-coated gold in calcine according to claim 1, wherein in S2, the liquid-solid ratio of water to iron-removing slag is 2-3:1, the pH of ore pulp is 7-9, the thiosulfate concentration in gold leaching agent is 0.1-0.3 mol/L, the ferricyanide concentration is 0.01-0.08 mol/L, the stirring speed is 200-300 rpm, and the leaching time is 2-4 h.
  10. 10. The method for leaching iron oxide-coated gold from calcine of claim 1, wherein the leaching rate of gold from the gold-bearing pregnant liquor is greater than 94%.

Description

Leaching method for iron oxide-coated gold in calcine Technical Field The invention belongs to the technical field of hydrometallurgy, and particularly relates to a leaching method of iron oxide-coated gold. Background In the hydrometallurgical field, raw materials containing gold pyrite, pyrrhotite, arsenopyrite and the like are roasted to produce a large amount of calcine containing iron oxides, wherein the iron oxides mainly comprise hematite (Fe 2O3) and magnetite (Fe 3O4). Due to the reconstruction of mineral lattices in the roasting process, the iron oxide can form a compact coating layer, and part of gold particles are coated in the coating layer, so that a subsequent gold leaching agent is difficult to effectively contact with gold, and the gold leaching rate is generally low. In order to solve the problem of iron oxide encapsulation, various schemes are proposed in the prior art, but the prior art has obvious defects, for example, a sulfuric acid leaching/curing method is used for dissolving hematite by utilizing sulfuric acid to generate sulfate, the method has the advantages of low raw material cost and high reaction rate, but the concentrated sulfuric acid has strong corrosiveness to equipment, and a large amount of generated sulfate waste liquid still needs to be subjected to subsequent treatment. The alkaline leaching/alkali decomposition method utilizes an alkaline medium to destroy iron oxide and silicon mineral packages, and the method is cleaner, but has high requirement on equipment alkali resistance and severe leaching condition. In the prior art, oxalic acid/oxalate is proposed to leach iron in calcine, the leaching rate of the method for iron in hematite is higher, but the solubility of oxalic acid/oxalate in aqueous solution is poor, the complexing capacity of oxalate and iron is limited, leaching is often required under the conditions of higher concentration and temperature, the subsequent gold recovery process adopts cyanide leaching, and acid-base conversion is required for process connection, so that a great amount of alkali is wasted. Therefore, developing an environment-friendly gold leaching process or method capable of efficiently breaking iron oxide packages is a technical problem to be solved in the hydrometallurgy field. Disclosure of Invention In order to solve the problem of low gold leaching rate caused by iron oxide coating in the prior art, the invention provides a leaching method for iron oxide coated gold in calcine, which can efficiently open iron oxide coating and leach gold, has low equipment requirement, reduces acid-base conversion process and has simple process. In order to solve the technical problems, the technical scheme provided by the invention is as follows: the invention provides a leaching method for iron oxide-coated gold in calcine, which comprises the following steps: S1, adding water into calcine to obtain ore pulp, adding an iron leaching agent, regulating a system to be weak acid, and carrying out solid-liquid separation after leaching to obtain iron-removing slag, wherein the iron leaching agent is a mixture of sulfosalicylic acid and sulfosalicylate, and the molar ratio of the sulfosalicylic acid to the sulfosalicylate in the mixture is 0.5-1:1-2.5; s2, adding water into the iron-removing slag obtained in the step S1 to prepare ore pulp, adjusting the pH value of the ore pulp to be neutral or weak alkaline, adding a gold leaching agent, and carrying out solid-liquid separation after leaching to obtain gold-leaching slag and gold-containing noble liquid. The iron leaching agent is a mixed solution of organic acid and salt thereof which can be matched with Fe 3+/Fe2+ and is stable under an acidic condition, wherein organic acid radical ions can form a complex which is stable and soluble in water with Fe 3+/Fe2+, fe 3+/Fe2+ in calcine can be removed through solid-liquid separation, and the package of gold is opened. In the invention, sulfosalicylic acid and sulfosalicylate are used as iron leaching agents, so that a buffer system for maintaining weak acidic conditions can be formed, the pH of a solution is too low when single acid is used, and the pH of the solution is too high when single salt is used, so that the coordination reaction is not facilitated. In the invention, the molar ratio of sulfosalicylic acid to sulfosalicylate is controlled to be 0.5-1:1-2.5, so that a buffer system for maintaining weak acidic conditions can be formed, the pH of a solution is too low when single acid is used, and the pH of the solution is too high when single salt is used, so that the coordination reaction is not facilitated. The slightly higher ratio of sulfosalicylate has higher efficiency and economy, particularly, the sulfosalicylate can be directly dissociated into negative bivalent/negative trivalent sulfosalicylate with high coordination activity in solution, and can be coordinated with iron efficiently and rapidly; in addition, the sulfosalicylate can p