CN114712893A - A kind of method of recovering gold in thiosulfate solution - Google Patents

Abstract

The invention discloses a method for recovering gold in thiosulfate solution, belonging to the technical field of hydrometallurgy and precious metal recovery. The invention isThe method comprises using a mixture containing amino (-NH) and imino (-NR)₂) The organic amine substance modified polyacrylonitrile fiber is washed to be neutral and dried; and then carrying out two-step modification by using aminated polyacrylonitrile fiber, aldehydes and phosphoric acid substances under reflux at a fixed temperature, and washing to be neutral to obtain the modified material. The functionalized polyacrylonitrile fiber prepared by the method can effectively adsorb and recover gold (Au (S) in thiosulfate gold leaching solution₂O₃)₂ ^3‑) (ii) a The used materials belong to the secondary utilization of industrial wastes, accord with the low-carbon environmental protection concept and have low cost. The material can efficiently recover gold (Au (S) in thiosulfate solution in short time₂O₃)₂ ^3‑) The method is suitable for actual production and is not easy to pulverize, and has important significance for the industrial development of thiosulfate gold extraction technology.

Description

A kind of method of recovering gold in thiosulfate solution

technical field

The invention relates to a method for recovering gold in a thiosulfate solution, belonging to the technical fields of hydrometallurgy and precious metal recovery.

Background technique

In the development of gold hydrometallurgy, the gold extraction technology in ore has gradually developed from the initial amalgamation method to the cyanide method. So far, cyanidation is still the most mainstream gold extraction method. However, the highly toxic cyanide in this law is likely to cause environmental pollution and ecological damage. Therefore, a large number of non-cyanide gold extraction methods have been studied. Among them, the thiosulfate gold leaching method has the advantages of fast gold leaching speed, non-toxicity, low reagent cost, environmental friendliness, easy to handle copper, arsenic and other cyanidation methods that are difficult to treat gold ores, and no corrosion to equipment. It is considered to be a green gold extraction technology that is most likely to replace the cyanide method. However, there are three main technical problems in the thiosulfate gold leaching system: (1) the consumption of thiosulfate is large, (2) the ammonia concentration required in the leaching process is high, and (3) the recovery of gold in the leaching solution is difficult. The first two problems can be basically solved by the copper-ammonia (amine) system instead. Therefore, the effective recovery of gold in the immersion solution has become the core technical problem faced by the industrialization of the thiosulfate method.

In order to solve this problem faster, many methods have been studied to recover gold (Au(S ₂ O ₃ ) ₂ ^3- ) in thiosulfate gold leaching solution. At present, there are four main methods for gold recovery from thiosulfate leaching gold solution: displacement method, adsorption method, solvent extraction method and electrodeposition method. When the replacement method is directly used to recover the gold in the thiosulfate leaching solution, the economic cost is too high, and it is difficult to be applied in actual production. Although the solvent extraction method has the advantages of high recovery rate, it is difficult to separate the solid and liquid of the pulp and the consumption of reagents is large. The electrodeposition method is suitable for the separation of gold when the gold concentration is high, but in the actual thiosulfate leaching solution, the gold content is generally relatively low, so it is not suitable for recovering gold in the thiosulfate leaching solution. The recovery of gold from thiosulfate solutions by electrodeposition is not yet mature. The adsorption method is favored by the majority of researchers due to its advantages of simple operation, low reagent cost and easy regeneration. Gold (Au(S ₂ O ₃ ) ₂ ^3- ) (the reason is: the coordinating group, the steric effect of the molecular structure, etc. lead to the long distance between the surface of the gold atom and the carbon) and many other disadvantages. Therefore, it is of great practical significance and necessity to seek a cost-effective and rapid method for recovering gold (Au(S ₂ O ₃ ) ₂ ^3- ) in thiosulfate leaching solution.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention provides a method for recovering gold (Au(S ₂ O ₃ ) ₂ ^3- ) in a thiosulfate solution, using certain functions contained in functionalized polyacrylonitrile fibers The atoms or groups interact with gold (Au(S ₂ O ₃ ) ₂ ^3- ) in the thiosulfate solution to achieve the adsorption effect.

In order to achieve the above purpose, the present invention adopts the following technical scheme: adding aminophosphonic acid-functionalized polyacrylonitrile fibers to the leaching solution containing (Au(S ₂ O ₃ ) ₂ ^3- ) on the gold (Au(S ₂ O ) in the solution ₃ ) ₂ ^3- ) stirring adsorption;

The preparation method of the functionalized polyacrylonitrile fiber is as follows:

(1) Wash the polyacrylonitrile fiber with deionized water to remove ash and impurities, and dry it for later use.

(2) Mix the polyacrylonitrile fibers in step (1) with organic amine reagents and deionized water, wash with hot water to neutrality after reflux reaction, and dry to obtain aminated polyacrylonitrile fibers for later use. The polyacrylonitrile fibers and The mixing ratio of organic amine reagent is 1 g: (20 ~ 100) ml, deionized water is the solvent and does not participate in the reaction, and the amount is not limited.

(3) The aminated polyacrylonitrile fibers obtained in step (2) are reacted with aldehydes, anhydrous ethanol, and phosphoric acid substances to be refluxed and washed to neutrality to obtain aminophosphonic acid-functionalized polyacrylonitrile fibers, which are dried for later use; wherein, The ratio of aminated polyacrylonitrile fibers, aldehydes, and phosphoric acid substances is 1 g: (10 ~ 30) ml: (3 ~ 8) g. Anhydrous ethanol is the solvent and does not participate in the reaction, and the amount is not limited.

Preferably, the polyacrylonitrile fiber in step (1) of the present invention is a high molecular organic substance rich in nitrile (-CN) and ester (-COOR) groups.

Preferably, the organic amine reagent in step (2) of the present invention is polyvinylpolyamine, containing amino and imino groups (-NH, -NH ₂ ), and the concentration is above 65%.

Further, the organic amine reagent described in step (2) of the present invention is a mixture obtained in any proportion of one or more of diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

Preferably, the aminophosphonic acid functionalized polyacrylonitrile fiber described in step (3) of the present invention is added to the thiosulfate gold leaching solution in an amount of 0.01 g/L to 0.2 g/L; the thiosulfate gold leaching solution The gold content is between 2 kg/t ~ 10 kg/t.

Preferably, the phosphoric acid substance in step (3) of the present invention is a mixture obtained by mixing one or more of hypophosphorous acid, phosphorous acid and phosphoric acid in proportion.

Preferably, the aldehydes in step (3) of the present invention are: a mixture of one or two of formaldehyde and acetaldehyde obtained in any proportion.

Preferably, the temperature range of the reflux reaction in step (2) of the present invention is 100-140°C, and the time is 2-8 h; the temperature range of the reflux reaction in step (3) is 50-90°C, and the time is 2-8 h .

Principle of the present invention: According to the above background, gold in thiosulfate gold leaching solution is usually recovered by adsorption method. Therefore, it is particularly necessary to select materials with low cost and easy modification. Based on the above background, the present invention selects polyacrylonitrile fibers that are rich in -CN and -COOR groups and is easily modifiable, and uses chemical grafting modification means to graft N and P-containing groups to polypropylene through two-step reflux method respectively. Finally, the gold in the thiosulfate gold leaching solution can be effectively adsorbed by the functionalized polyacrylonitrile fibers.

The beneficial effects of the present invention are:

(1) The present invention uses industrial waste polyacrylonitrile fibers to adsorb gold in thiosulfate solution, which belongs to the secondary utilization of waste, is environmentally friendly, and conforms to the low-carbon concept. The price is cheap; the material is easy to obtain, non-toxic and harmless, and the adsorption capacity of gold is high.

(2) The material can efficiently recover gold (Au(S ₂ O ₃ ) ₂ ^3- ) in thiosulfate solution in a short time, a highly efficient recovery (Au(S ₂ O ₃ ) ₂ ^3- ) solution The method of gold (I); it is suitable for actual production and is of great significance to the industrial development of thiosulfate gold extraction technology.

(3) The prepared functionalized polyacrylonitrile fiber can have a good adsorption effect on gold (Au(S ₂ O ₃ ) ₂ ^3- ) in the thiosulfate leaching solution; only 0.5 g of adsorption The gold loading of the material can reach 7 kg/t. The reason why the functionalized polyacrylonitrile fiber has an adsorption effect on the gold (Au(S ₂ O ₃ ) ₂ ^3- ) in the thiosulfate leaching solution is due to grafting. The added N was protonated to form NRnH ⁺ OH ^- . After adsorption, anion exchange occurred between OH ^- and Au(S ₂ O ₃ ) ₂ ^3- and chelation occurred between P and Au (Ⅰ). The result of the synergistic effect used.

Detailed ways

The present invention will be further described below with reference to the specific embodiments, but the protection scope of the present invention is not limited to the content.

In the embodiment of the present invention, a self-prepared gold leaching solution is used as an example for illustration. The gold in the gold leaching solution is gold (Au(S ₂ O ₃ ) ₂ ^3- ) in a thiosulfate solution. The thiosulfate concentration was 0.01 mol/L ~ 0.4 mol/L, the gold concentration was 5 mg/L ~ 65 mg/L, the stirring adsorption time was 0.05 h ~ 24 h, and the temperature was 25 ℃ ~ 65 ℃. The solid-liquid ratio of polyacrylonitrile fiber to thiosulfate gold leaching solution is 1: 200 ~ 1: 50.

Example 1

In this example, diethylenetriamine and phosphorous acid are used as modifiers, and functionalized polyacrylonitrile fibers are used to recover gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution, including the following steps:

(1) The washed polyacrylonitrile fibers, diethylenetriamine, and deionized water were refluxed at 140 °C for 4 h at the ratio of 1 g : 20 ml : 10 ml to obtain aminated polyacrylonitrile fibers.

(2) Take the aminated polyacrylonitrile fiber with 40% formaldehyde, anhydrous ethanol and solid phosphorous acid in the ratio of 1 g : 10 ml : 25 ml : 5 g and reflux at 80 ℃ for 4 h to obtain functionalized polyacrylonitrile fiber .

(3) Take 0.5 g of the functionalized fiber adsorbent obtained in step (2) and add it to 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- concentration of 25 mg/L gold leaching solution for gold Au(S ₂ O ₃ ) ₂ ^3- was adsorbed and stirred, the solid-liquid ratio was 1:200 at this time, the adsorption time was 24h, and the initial pH was 9.0.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 1.56 kg/t.

Example 2

In this example, triethylenetetramine and phosphorous acid are used as modifiers, and functionalized polyacrylonitrile fibers are used to recover gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution, including the following steps:

(1) The washed polyacrylonitrile fiber was refluxed with triethylenetetramine and deionized water at a ratio of 1 g : 30 ml : 10 ml at 140 °C for 4 h to obtain aminated polyacrylonitrile fiber.

(2) Take the aminated polyacrylonitrile fiber, reflux it with 40% formaldehyde, absolute ethanol and solid phosphorous acid in the ratio of 1 g : 10 ml : 25 ml : 5 g at 80 ℃ for 4 h to obtain functionalized polypropylene Acrylic fiber.

(3) Take 0.5 g of the functionalized fiber obtained in step (2) and add it to a 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- gold leaching solution with a concentration of 25 mg/L for gold Au(S ₂ O ₃ ) ₂ ^3- Carry out adsorption and stirring, the solid-liquid ratio is 1:200 at this time, the adsorption time is 24 h, and the initial pH is 9.0.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 7.00 kg/t.

Example 3

In this embodiment, tetraethylene pentamine and hypophosphorous acid are used as modifiers, and functionalized polyacrylonitrile fibers are used to recover gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution, including the following steps:

(1) The washed polyacrylonitrile fiber was refluxed with tetraethylene pentamine and deionized water in the ratio of 1 g : 40 ml : 10 ml at 140 °C for 4 h to obtain aminated polyacrylonitrile fiber.

(2) Take the aminated polyacrylonitrile fiber, reflux it with 40% acetaldehyde, absolute ethanol and solid hypophosphorous acid in the ratio of 1 g: 20 ml: 25 ml: 5 g at 80 °C for 4 h to obtain functionalized polyacrylonitrile fibers. Acrylic fiber.

(3) Take 0.5 g of the functionalized fiber obtained in step (2), add it to 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- concentration of 25 mg/L gold leaching solution for gold Au(S ₂ O ₃ ) ₂ ^3- Carry out adsorption and stirring, the solid-liquid ratio is 1:200 at this time, the adsorption time is 24 h, and the initial pH is 9.0.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 2.54 kg/t.

Example 4

In this embodiment, triethylenetetramine and hypophosphorous acid are used as modifiers, and functionalized polyacrylonitrile fibers are used to recover gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution, including the following steps:

(1) The washed polyacrylonitrile fibers were refluxed with triethylenetetramine and deionized water at the ratio of 1 g : 100 ml : 10 ml at 140 °C for 4 h to obtain aminated polyacrylonitrile fibers.

(2) Take the aminated polyacrylonitrile fiber and reflux it with 40% formaldehyde, anhydrous ethanol and hypophosphorous acid in the ratio of 1 g : 30 ml : 25 ml : 3 g at 80 °C for 4 h to obtain functionalized polyacrylonitrile fibers .

(3) Take 0.5 g of the functionalized fiber obtained in step (2) and add it to a 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- gold leaching solution with a concentration of 25 mg/L for gold Au(S ₂ O ₃ ) ₂ ^3- Carry out adsorption and stirring, the solid-liquid ratio is 1:200 at this time, the adsorption time is 24 h, and the initial pH is 9.0.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 2.58 kg/t.

Example 5

In this example, tetraethylene pentamine and phosphoric acid are used as modifiers, and the gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution is recovered with functionalized polyacrylonitrile fibers, including the following steps:

(1) The washed polyacrylonitrile fibers, tetraethylene pentamine and deionized water were refluxed at 140 °C for 4 h at the ratio of 1 g : 20 ml : 10 ml to obtain aminated polyacrylonitrile fibers.

(2) Take the aminated polyacrylonitrile fiber, reflux it with 40% acetaldehyde, absolute ethanol and solid phosphoric acid in the ratio of 1 g : 30 ml : 25 ml : 5 g at 80 ℃ for 4 h to obtain functionalized polypropylene Acrylic fiber.

(3) Take 0.5 g of the functionalized fiber obtained in step (2) and add it to a 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- gold leaching solution with a concentration of 25 mg/L for gold Au(S ₂ O ₃ ) ₂ ^3- Carry out adsorption and stirring, adjust the initial pH to 6.0, the solid-liquid ratio to 1:200, and the adsorption time to 24 h.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 1.59 kg/t.

Example 6

In this embodiment, triethylenetetramine and phosphoric acid are used as modifiers, and functionalized polyacrylonitrile fibers are used to recover gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution, including the following steps:

(1) Reflux the washed polyacrylonitrile fibers with triethylenetetramine and deionized water at the ratio of 1g: 20 ml: 10 ml at 140 °C for 4 h to obtain aminated polyacrylonitrile fibers.

(2) Take the material obtained in step (1), and reflux it with 40% formaldehyde, absolute ethanol and solid phosphoric acid in a ratio of 1g: 10ml: 25ml: 8g at 80 °C for 4 hours to obtain functionalized polyacrylonitrile fibers.

(3) Take 0.5 g of the functionalized fiber obtained in step (2) and add it to a 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- gold leaching solution with a concentration of 25 mg/L for gold Au(S ₂ O ₃ ) ₂ ^3- Carry out adsorption and stirring, adjust the initial pH to 11.0, the solid-liquid ratio to 1:200, and the adsorption time to 24 h.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 3.98 kg/t.

Example 7

In this example, tetraethylene pentamine and phosphorous acid are used as modifiers, and the gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution is recovered with functionalized polyacrylonitrile fibers, including the following steps:

(1) The washed polyacrylonitrile fiber was refluxed with tetraethylene pentamine and deionized water at the ratio of 1 g : 20 ml : 10 ml at 140 °C for 4 h to obtain aminated polyacrylonitrile fiber.

(2) Take the aminated polyacrylonitrile fiber, reflux it with 40% acetaldehyde, absolute ethanol and solid phosphorous acid at the ratio of 1 g : 30 ml : 25 ml : 8 g at 80 ℃ for 4 h to obtain functionalized polyacrylonitrile Acrylic fiber.

(3) Take 0.5 g of the functionalized fiber obtained in step (2) and add it to a 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- gold leaching solution with a concentration of 25 mg/L for gold Au(S ₂ O ₃ ) ₂ ^3- Carry out adsorption and stirring. At this time, the solid-liquid ratio is 1:200, the adsorption time is 24 h, and the initial pH is 9.0.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 2.34 kg/t.

Example 8

In this example, triethylenetetramine and phosphorous acid modifier are used to recover gold Au(S ₂ O ₃ ) ₂ ^3- in the thiosulfate solution with functionalized polyacrylonitrile fibers, including the following steps:

(1) The washed polyacrylonitrile fibers were refluxed with triethylenetetramine and deionized water at the ratio of 1 g : 20 ml : 10 ml at 140 °C for 4 h to obtain aminated polyacrylonitrile fibers.

(2) Take the aminated polyacrylonitrile fiber, reflux it with 40% formaldehyde, anhydrous ethanol and solid phosphorous acid at the ratio of 1 g : 10 ml : 25 ml : 3 g at 80 ℃ for 4 h to obtain functionalized polypropylene Acrylic fiber.

(3) Take 0.5 g of the functionalized fiber obtained in step (2) and add it to a 100 mL volume, Au(S ₂ O ₃ ) ₂ ^3- concentration of 25 mg/L gold leaching solution for gold Au(S ₂ O ₃ ) ₂ ^3- Carry out adsorption and stirring, the solid-liquid ratio is 1:200 at this time, the adsorption time is 24 h, and the initial pH is 9.0.

The gold loading on the functionalized polyacrylonitrile fibers was calculated to be 2.67 kg/t.

The specific embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-mentioned embodiments. Various changes can be made within the scope of knowledge possessed by those of ordinary skill in the art without departing from the spirit of the present invention. .

Claims (8)

1. A method for recovering gold from a thiosulfate solution, characterized in that: putting the modified polyacrylonitrile fiber into thiosulfate gold leaching solution for adsorption and recovery (Au (S)₂O₃)₂ ^3-)；

The preparation method of the functionalized polyacrylonitrile fiber comprises the following steps:

(1) washing polyacrylonitrile fibers with deionized water to remove ash and impurities, and drying for later use;

(2) mixing the polyacrylonitrile fiber in the step (1) with an organic amine reagent and deionized water, washing the mixture to be neutral by hot water after reflux reaction, and drying the mixture to obtain aminated polyacrylonitrile fiber for later use, wherein the mixing ratio of the polyacrylonitrile fiber to the organic amine reagent is 1g (20-100) ml;

(3) carrying out reflux reaction on the aminated polyacrylonitrile fiber obtained in the step (2) with aldehydes, absolute ethyl alcohol and phosphoric acid substances, washing to be neutral to obtain aminophosphonic acid functionalized polyacrylonitrile fiber, and drying for later use; wherein the proportion of the aminated polyacrylonitrile fiber, the aldehydes and the phosphoric acid substances is 1g (10-30) ml (3-8).

2. The method of recovering gold in thiosulfate solution in accordance with claim 1, characterized in that: the mass of the added functional polyacrylonitrile fiber adsorbent is 0.01-0.2 g/L, and the gold content in the thiosulfate gold leaching solution is 2-10 kg/t.

3. The method of recovering gold in thiosulfate solution in accordance with claim 1, characterized in that: and (3) the organic amine reagent in the step (2) is a polyethylene polyamine containing amino and imino.

4. The method of recovering gold in thiosulfate solution in accordance with claim 3, characterized in that: the organic amine reagent in the step (2) is: one or a mixture of a plurality of diethylenetriamine, triethylene tetramine and tetraethylenepentamine in any proportion.

5. The method for recovering gold in thiosulfate solution according to any one of claims 1 to 4, characterized in that: the temperature range of the reflux reaction in the step (2) is 100-140 ℃, and the time is 2-8 h.

6. The method of recovering gold in thiosulfate solution in accordance with claim 1, characterized in that: and (3) the phosphoric acid substance is a mixture obtained by one or more of hypophosphorous acid, phosphorous acid and phosphoric acid according to any proportion.

7. The method of recovering gold in thiosulfate solution in accordance with claim 1, characterized in that: the aldehyde substance in the step (3) is one or a mixture of two of formaldehyde and acetaldehyde in any proportion.

8. The method of recovering gold in thiosulfate solution in accordance with any one of claims 1, 6, 7, characterized in that: the temperature range of the reflux reaction in the step (3) is 50-90 ℃, and the time is 2-8 h.