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Stable alkali thiourea system and its selective immersion gold method

A selectivity and thiourea technology, applied in the direction of improving process efficiency, etc., can solve problems such as complex solution regeneration and purification process, insoluble gold, equipment corrosion, etc., and achieve the promotion of sustainable and coordinated development, non-toxic gold leaching, and operation requirements low effect

Inactive Publication Date: 2005-09-14
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the acidic thiourea gold leaching process, thiourea is first oxidized to dithioformamidine, which is further irreversibly decomposed into cyanamide, resulting in excessive consumption of thiourea; thiourea easily reacts with other metals in the gold ore, resulting in a lower gold leaching efficiency , The solution regeneration and purification process is complex; and the acidic solution is easy to cause corrosion of equipment, which limits the industrial application of acidic thiourea
It is generally believed that thiourea is more unstable in alkaline medium than in acidic medium, and is easily decomposed into sulfide and cyanamide. It has been reported that the pH value must be less than 1.78 when thiourea dissolves gold, otherwise gold cannot be dissolved; Little soluble in unstable alkaline thiourea solution and almost of no practical significance

Method used

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  • Stable alkali thiourea system and its selective immersion gold method
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  • Stable alkali thiourea system and its selective immersion gold method

Examples

Experimental program
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Effect test

Embodiment 1

[0015] Embodiment 1: Alkaline thiourea system

[0016] at 0.1mol·L -1 Add 0.25mol·L to the thiourea solution -1 Stabilizer Na 2 SO 3 To form a thiourea system, add 0.2mol L -1 Stabilizer Na 2 SiO 3 Form another thiourea system, and adjust the pH value of the solution to be 12.5. When the temperature is 25°C, the gold electrode is used as the working electrode, and the scanning speed is 10mV s -1 The open circuit potential of the solution was investigated, and the concentration of thiourea was determined by the volumetric method to investigate the change of the decomposition rate of thiourea in the two systems.

[0017] With Na 2 SO 3 、Na 2 SiO 3 Add slowly, 0.1mol·L -1 The initial open circuit potential of the alkaline thiourea solution drops from -0.2V to -0.25V and -0.29V respectively, and the solution can reach a steady state in about 500 seconds, the stable potentials are all -0.27V, and the decomposition rate of thiourea is 72.5%. With the addition of stabil...

Embodiment 2

[0018] Embodiment 2: the immersion gold of high stability alkaline thiourea system

[0019] The raw material is oxidized gold ore after microbial treatment, and the main phase is SiO 2 , the gold content is 51.4g / t. The main steps of the leaching process are as follows:

[0020] First add a certain amount of water into the reaction kettle with air stirring and mechanical stirring, and add 0.25mol L in turn under the condition of mechanical stirring -1 Stabilizer Na 2 SiO 3 and thiourea 0.15mol L -1 , and mix evenly; pour a certain amount of oxidized gold ore into the reactor according to the solid-liquid ratio of 1:10, fully mix with the leaching solution, then add a metered amount of oxidant, and adjust the pH value of the solution to 12.5; stop the mechanical stirring, Start the air stirring, leaching at room temperature for 4 hours; after the reaction is completed, filter; the leaching solution is adsorbed by activated carbon, and the concentration of each component is...

Embodiment 3

[0021] Embodiment 3: the immersion gold of high stability alkaline thiourea system

[0022] The raw material is oxidized gold ore after microbial treatment, and the main phase is SiO 2 , the gold content is 51.4g / t. The main steps of the leaching process are as follows: First, add a certain amount of water to the reaction kettle with air stirring and mechanical stirring, and add 0.15mol L in turn under the condition of mechanical stirring -1 Stabilizer Na 2 SiO 3 and thiourea 0.15mol L -1 , and mix evenly; pour a certain amount of oxidized gold ore into the reaction kettle according to the solid-liquid ratio of 1:8, fully mix with the leaching solution, then add a metered amount of oxidant, and adjust the pH value of the solution to 12.5; stop mechanical stirring, Start the air stirring, leaching at room temperature for 4 hours; after the reaction is completed, filter; the leaching solution is adsorbed by activated carbon, and the concentration of each component is adjuste...

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Abstract

This invention is stable alkaline thiourea system and its selective dunking gold method. the materials are gold mine of low sulfur content, calcine or gold contain abatement. Cyanogens lixiviant is alkaline thiourea, stabilizer is sodium sulphite or sodium silicate, they constitute high stability alkaline thiourea system, and bland oxidizing agent is potassium ferricyanide with moderate electric potential during sunking process. Alkaline thiourea stability problem is solved radically, reagents used in this invention is nontoxic, gold dissolving is fast, the reaction only needs 3~4 hours, dunking gold rate is 80%. There is selectivity in gold dissolving, associated metal or basic metal as Fe, Co, Ni, Cu, Ag of waste gold matter is not easy corrode in alkaline condition. Gold recovery from dunking solution is convenient. There is almost no corruption to equipment comparing to acid solution, equipment design and run requirement is low.

Description

technical field [0001] The present invention relates to a highly stable alkaline thiourea system and its selective gold leaching method, in particular to a high-efficiency gold leaching system composed of a mild oxidant, alkaline thiourea and its stabilizer, and using the system A method for efficiently and selectively leaching gold from gold ore or gold-bearing waste. Background technique [0002] Since the discovery that gold can be dissolved in alkaline cyanide solution in the 19th century, the extraction and smelting of gold has been vigorously developed, especially the application of advanced technologies such as carbon slurry method, carbon leaching method, resin slurry method and cyanide heap leaching, so that Cyanide gold extraction technology is becoming more and more perfect. Cyanide gold leaching, as a classic method, is simple in operation, high in gold recovery rate and low in production cost. Cyanide is currently the most effective gold leaching reagent for tr...

Claims

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Application Information

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IPC IPC(8): C22B3/16
CPCY02P10/20
Inventor 柴立元王云燕闵小波彭兵
Owner CENT SOUTH UNIV
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