A method of treating a gold ore having fine particles coated with bismuth sulfide

Abstract

The present application relates to a kind of processing bismuth sulfide wrapped fine gold ore method, belong to precious metal and non-ferrous metal recovery technical field.A kind of processing bismuth sulfide wrapped fine gold ore method, bismuth gold ore containing bismuth sulfide powder is prepared into ore pulp with water, the bismuth sulfide in ore is reacted to generate gaseous hydrogen sulfide, bismuth ion-containing solution and solid gold concentrate containing precious metal gold with ore pulp and leaching agent mixing;Collect gaseous hydrogen sulfide, and make it subsequently with the bismuth ion-containing solution obtained above reaction to generate bismuth sulfide;Extract metal gold in solid gold concentrate.The present application uses inorganic acid to separate gold bismuth, opens bismuth mineral package, releases gold mineral, and then uses own product to change reaction condition and carries out regeneration reaction, in this process not only enriches and recycles bismuth concentrate, but also regenerates gold bismuth separation leaching agent, saves production cost, and reaction process has no waste release.

Description

Technical Field

[0001] This invention relates to a method for processing fine-grained gold ore encapsulated in bismuth sulfide, belonging to the field of precious metal and non-ferrous metal recycling technology. Background Technology

[0002] Gold (Au) and bismuth (Bi) are two important metallic resources found in bismuth-gold mines, with wide applications in electronics, metallurgy, and medicine. Gold, a precious metal, possesses excellent electrical conductivity and stability, making it suitable for high-end electronic devices, while bismuth, due to its low melting point and non-toxic properties, holds a place in the pharmaceutical and chemical industries. With the increasing demand for these metals, how to efficiently, economically, and reliably separate and recover gold and bismuth from bismuth-gold mines has become an important research topic.

[0003] Bismuth-gold ores have complex mineral compositions. Bismuth in the ore often exists in the form of bismuth sulfide, bismuth telluride, and bismuth oxide, while gold is often embedded in the bismuth ore in the form of fine particles, flakes, or agglomerates, posing a challenge to gold recovery. Traditional hydrometallurgical recovery processes for bismuth-gold ores include crushing, grinding, flotation, gravity separation, and cyanide leaching to remove bismuth and enrich gold. Common methods for processing bismuth ore also include ferric chloride leaching-iron powder replacement, ferric chloride leaching-diaphragm electrowinning, ferric chloride leaching-hydrolysis precipitation of bismuth, chlorine selective leaching, and hydrochloric acid-nitrous acid leaching. Each of these methods has its own advantages and disadvantages. For example, the ferric chloride leaching-iron powder replacement method has a high leaching rate but low environmental pollution, high material consumption, and large wastewater discharge. The ferric chloride leaching-diaphragm electrodeposition method can reduce the circulation and accumulation of iron ions in the process, but the control of electrode potential and the rate at which the solution permeates through the diaphragm is relatively complex. The ferric chloride leaching-hydrolysis precipitation of bismuth method has high water and reagent consumption, low bismuth recovery rate, and large wastewater discharge. The chlorine selective leaching method eliminates the circulation and accumulation of a large number of iron ions in the process, but the consumption of chlorine is high, and some elemental sulfur will be further oxidized to sulfate, resulting in serious chlorine pollution and corrosion. The hydrochloric acid-nitrous acid leaching method can improve the leaching rate of bismuth, but its environmental impact cannot be ignored.

[0004] To address the problems of traditional processing techniques, researchers have attempted to develop new green wet recycling technologies. These technologies aim to improve the recovery efficiency of gold and bismuth while reducing environmental pollution by optimizing leaching conditions, developing novel leaching agents, and introducing advanced separation techniques. However, these methods often require high costs and have limitations in practical industrial applications.

[0005] The present invention aims to provide a new method for bismuth extraction from bismuth-gold ore. This method can efficiently separate gold minerals from bismuth ore, thereby increasing the gold leaching rate. It also enables the recovery of leaching agents and bismuth minerals, reducing production costs and environmental pollution. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for processing fine-grained gold ore encapsulated in bismuth sulfide, which can open the bismuth mineral encapsulation, release and enrich gold. At the same time, the innovative process route not only realizes the regeneration of leaching agent, but also achieves the separation of gold and bismuth without the generation of pollutants. More importantly, this invention achieves the efficient separation of gold minerals and bismuth minerals, thereby improving the gold extraction rate of bismuth-gold ore.

[0007] A method for processing fine-grained gold ore encapsulated in bismuth sulfide involves preparing a slurry from bismuth-gold ore powder containing bismuth sulfide with water, mixing the slurry with a leaching agent to cause the bismuth sulfide in the ore to react and generate gaseous hydrogen sulfide, a solution containing bismuth ions, and a solid gold concentrate containing metallic gold; collecting the gaseous hydrogen sulfide and subsequently reacting it with the aforementioned solution containing bismuth ions to generate bismuth sulfide; and extracting metallic gold from the solid gold concentrate.

[0008] In the above technical solution, it is preferable to react the recovered gaseous hydrogen sulfide and fresh gaseous hydrogen sulfide with the obtained bismuth ion-containing solution to generate bismuth sulfide. This invention uses the recovered hydrogen sulfide to react with the bismuth ion-containing solution to obtain bismuth sulfide. When the recovered hydrogen sulfide is insufficient, fresh hydrogen sulfide can be added as needed for the reaction.

[0009] In the above technical solution, the preferred bismuth-gold ore powder is a powder with a particle size of 38-45μm or more accounting for more than 90%, a bismuth grade of 10-20%, and a gold grade of 12-20g / t.

[0010] In the above technical solution, it is preferable to add a gold extraction agent to solid gold concentrate to extract gold products. The method for extracting gold from solid gold concentrate is existing technology in this field.

[0011] In the above technical solution, the leaching agent is preferably concentrated hydrochloric acid or sulfuric acid. Furthermore, when sulfuric acid is used as the leaching agent, it is used in conjunction with a sodium chloride solution to prevent bismuth chloride from hydrolyzing and forming bismuth oxychloride precipitate.

[0012] A preferred technical solution of the present invention is as follows: bismuth-gold ore slurry is mixed with concentrated hydrochloric acid to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and hydrothiolic acid, and a solid gold concentrate containing metallic gold; in a sealed container, the mixed solution containing bismuth chloride and hydrothiolic acid is reacted with the recovered gaseous hydrogen sulfide to obtain bismuth sulfide concentrate and hydrogen chloride solution.

[0013] Further, a bismuth-gold ore slurry with a mass fraction of 5-30% is placed in a reactor, concentrated hydrochloric acid is added, and the mixture is stirred at -10 to 5°C. The liquid-to-solid volume-to-mass ratio is controlled at 10:1 to 25:1. After reacting for 60-120 minutes, solid-liquid separation is rapidly performed to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and hydrothiolic acid, and a solid gold concentrate containing metallic gold. The mixed solution containing bismuth chloride and hydrothiolic acid is transferred to a closed reaction vessel, and gaseous hydrogen sulfide is introduced. The mixture is stirred at 20-80°C for 60-90 minutes to obtain bismuth sulfide concentrate and a hydrogen chloride solution.

[0014] Another preferred technical solution of the present invention is as follows: bismuth-gold ore slurry is mixed with sulfuric acid solution until the pH value of the system is 0.5-1.5, and then a certain amount of sodium chloride is added to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and sodium sulfate, and a solid gold concentrate containing metallic gold; the mixed solution containing bismuth chloride and sodium sulfate is reacted with calcium chloride to obtain solid gypsum and a mixed solution containing bismuth chloride and sodium chloride; in a sealed container, the mixed solution containing bismuth chloride and sodium chloride is reacted with recovered gaseous hydrogen sulfide to obtain bismuth sulfide concentrate and sodium chloride solution.

[0015] Further, a 5-30% (w / w) bismuth-gold ore slurry is mixed with a 50% (w / w) sulfuric acid solution until the pH of the system is 0.5-1.5. Sodium chloride is then added, and the mixture is stirred at 50-90°C. The molar amount of sodium chloride is 2-2.5 times that of sulfuric acid. After reacting for 90-150 min, solid-liquid separation is rapidly performed to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and sodium sulfate, and a solid gold concentrate containing metallic gold. The mixed solution containing bismuth chloride and sodium sulfate is then reacted with a 20-30% (w / w) calcium chloride solution. The molar amount of calcium chloride is 1-1.2 times that of sulfuric acid. The reaction is carried out at room temperature to obtain solid gypsum and a mixed solution containing bismuth chloride and sodium chloride. The mixed solution containing bismuth chloride and sodium chloride is then transferred to a closed reaction vessel, and gaseous hydrogen sulfide is introduced. The mixture is stirred at 30-60°C for 60-120 min to obtain bismuth sulfide concentrate and a sodium chloride solution.

[0016] Preferably, the concentrated hydrochloric acid is a recovered hydrogen chloride solution or a recovered hydrogen chloride solution prepared by mixing; the sodium chloride is a recovered sodium chloride solution or a recovered sodium chloride solution prepared by mixing.

[0017] The beneficial effects of this invention are as follows: This invention uses inorganic acids for gold-bismuth separation, opening the bismuth mineral encapsulation and releasing enriched gold minerals. Subsequently, it utilizes its own products to modify reaction conditions for a regeneration reaction. In this process, not only is bismuth concentrate enriched and recovered, but the gold-bismuth separation leaching agent is also regenerated, saving production costs, and the reaction process releases no waste. More importantly, the implementation of this invention can significantly improve the gold extraction rate of bismuth-gold ore, achieving a balance of social, economic, and environmental benefits. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the principle of the present invention;

[0019] Figure 2 This is a flowchart of the method for improving the gold leaching rate by treating bismuth-encapsulated fine gold particles with concentrated hydrochloric acid as the leaching agent according to the present invention.

[0020] Figure 3 This is a flowchart of the method for improving the gold leaching rate by treating bismuth-encapsulated fine gold particles with sulfuric acid as a leaching agent, as described in this invention. Detailed Implementation

[0021] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0022] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0023] One specific implementation method: (using concentrated hydrochloric acid as the leaching agent)

[0024] A method for processing fine-grained gold ore encapsulated in bismuth sulfide includes the following steps:

[0025] (1) Gold-bismuth separation: A certain mass of bismuth-gold ore is mixed with water to form a slurry. The slurry is placed in a reactor and stirred at a certain temperature. Then, a certain amount of leaching agent (36-38% concentrated hydrochloric acid) is added to it. The liquid-solid volume-to-mass ratio is controlled to be 10:1-25:1. After reacting for 60-120 minutes, solid-liquid separation is carried out rapidly to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The obtained gold concentrate is sent to the gold extraction process, while liquid phase 1 and gaseous hydrogen sulfide enter the regeneration process.

[0026] (2) Gold extraction: Add gold extraction agent to the gold concentrate obtained in step (1) to extract gold, refine the gold product and calculate the gold extraction rate;

[0027] (3) Regeneration: The liquid phase 1 obtained after separating gold and bismuth is transferred into a closed reaction vessel with gaseous hydrogen sulfide and stirred at a certain temperature. After 60-90 minutes, the reaction ends and solid-liquid separation is performed to obtain bismuth concentrate and liquid phase 2.

[0028] Furthermore, in step (1), the bismuth-gold ore has a particle size of 38-45 μm or more, accounting for more than 90%; the bismuth grade in the bismuth-gold ore is 10-20%, and the gold grade is 12-20 g / t;

[0029] Further, the reaction temperature in step (1) is -10 to 5°C, and the stirring speed is 300 to 600 rpm;

[0030] Further, the gold concentrate grade in step (1) is 25-40 g / t, and the liquid phase 1 is a mixture of bismuth chloride and hydrosulfuric acid;

[0031] Furthermore, the gold extraction agent mentioned in step (2) is a conventional agent, such as sodium cyanide, sodium thiosulfate, cicada, etc.; the gold extraction method is a common gold extraction method, such as carbon-in-pulp gold extraction process, cyanide-zinc replacement process, pyrometallurgical smelting, electrolysis, etc.

[0032] Furthermore, the reaction temperature in step (3) is 20–80°C, and the stirring speed is 200–400 rpm.

[0033] Furthermore, the bismuth concentrate grade in step (3) is 25-35%; the liquid phase 2 is a hydrochloric acid solution, which can be reused in the bismuth-gold ore slurry preparation and gold-bismuth separation process in step (1).

[0034] The following embodiments are all in accordance with Figure 2 The process flow shown is carried out, and the bismuth-gold ore used is mined from the same mining area. The bismuth grade in the raw ore is 10-20%, and the gold grade is 12-20 g / t.

[0035] Example 1

[0036] (1) Separation of gold and bismuth: 100 kg of bismuth-gold ore with a particle size of 38-45 μm and a content of 90% was mixed with 500 L of water to form a slurry. The slurry was placed in a reactor and stirred at 300 rpm at 0 °C. 500 L of concentrated hydrochloric acid was added. The liquid-to-solid volume ratio was 10:1. After reacting for 60 min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 30 g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0037] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of sodium cyanide was completed after 40 hours. According to the test and calculation, the leaching rate of gold was 90.33%.

[0038] (3) Regeneration: The liquid phase 1 generated during the gold-bismuth separation process and the gaseous hydrogen sulfide are transferred into a closed reaction vessel and stirred at 200 rpm for 60 min at 20℃. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 25%, and the liquid phase is hydrochloric acid solution.

[0039] Comparative Example 1

[0040] A cyanidation gold extraction test was conducted directly using the bismuth-gold ore used in Example 1 as raw material. The gold extraction test conditions were exactly the same as those in step 2, and the final gold leaching rate was 51.6%.

[0041] Example 2

[0042] (1) Separation of gold and bismuth: 100 kg of bismuth-gold ore with a particle size of 38-45 μm and a content of 95% was mixed with hydrochloric acid solution obtained from the bismuth regeneration process in Example 1 and placed in a reactor. The mixture was stirred at 400 rpm at 5°C without adding concentrated hydrochloric acid. The liquid-to-solid volume ratio was 10:1. After reacting for 90 min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 25 g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0043] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of sodium cyanide was completed after 40 hours. According to the test and calculation, the gold leaching rate was 88.53%.

[0044] (3) Regeneration: The liquid phase 1 generated during the gold-bismuth separation process and gaseous hydrogen sulfide are transferred into a closed reaction vessel and stirred at 300 rpm for 75 min at 30°C. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 30%, and the liquid phase is hydrochloric acid solution.

[0045] Example 3

[0046] (1) Separation of gold and bismuth: 100 kg of bismuth-gold ore with a particle size of 38-45 μm and a content of 98% was mixed with hydrochloric acid solution obtained from the bismuth regeneration process in Example 2 and placed in a reactor. The mixture was stirred at 500 rpm at -5℃ and 500 L of concentrated hydrochloric acid was added. The liquid-solid volume mass ratio was 15:1. After reacting for 120 min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 35 g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0047] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of sodium cyanide was completed after 40 hours. According to the test and calculation, the gold leaching rate was 93.12%.

[0048] (3) Regeneration: The liquid phase 1 generated during the gold-bismuth separation process and gaseous hydrogen sulfide are transferred into a closed reaction vessel and stirred at 350 rpm for 80 min at 40℃. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 35%, and the liquid phase is hydrochloric acid solution.

[0049] Example 4

[0050] (1) Separation of gold and bismuth: 100 kg of bismuth-gold ore with a particle size of 38-45 μm and a content of 96% was mixed with hydrochloric acid solution obtained from the bismuth regeneration process in Example 3 and placed in a reactor. The mixture was stirred at 500 rpm at -5℃ without adding concentrated hydrochloric acid. The liquid-to-solid volume ratio was 15:1. After reacting for 120 min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 30 g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0051] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of sodium cyanide was completed after 40 hours. According to the test and calculation, the gold leaching rate was 89.63%.

[0052] (3) Bismuth regeneration: The liquid phase 1 generated during the gold-bismuth separation process and gaseous hydrogen sulfide are transferred into a closed reaction vessel and stirred at 350 rpm for 80 min at 40℃. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 30%, and the liquid phase is hydrochloric acid solution.

[0053] Example 5

[0054] (1) Separation of gold and bismuth: 100 kg of bismuth-gold ore with a particle size of 38-45 μm and a content of 94% was mixed with hydrochloric acid solution obtained from the bismuth regeneration process in Example 4 and placed in a reactor. The mixture was stirred at 600 rpm at -10℃ and 500 L of concentrated hydrochloric acid was added. The liquid-solid volume mass ratio was 20:1. After reacting for 60 min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 38 g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0055] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of sodium cyanide was completed after 40 hours. According to the test and calculation, the gold leaching rate was 95.71%.

[0056] (3) Regeneration: The liquid phase 1 generated during the gold-bismuth separation process and gaseous hydrogen sulfide are transferred into a closed reaction vessel and stirred at 350 rpm for 75 min at 60°C. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 35%, and the liquid phase is hydrochloric acid solution.

[0057] Example 6

[0058] (1) Separation of gold and bismuth: 100 kg of bismuth-gold ore with a particle size of 38-45 μm and a content of 93% was mixed with hydrochloric acid solution obtained from the bismuth regeneration process in Example 5 and placed in a reactor. The mixture was stirred at 600 rpm at -10℃ without adding concentrated hydrochloric acid. The liquid-to-solid volume ratio was 20:1. After reacting for 90 min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 35 g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0059] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of sodium cyanide was completed after 40 hours. According to the test and calculation, the gold leaching rate was 92.07%.

[0060] (3) Regeneration: The liquid phase 1 generated during the gold-bismuth separation process and the gaseous hydrogen sulfide are transferred into a closed reaction vessel and stirred at 300 rpm for 60 min at 70°C. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 30%, and the liquid phase is hydrochloric acid solution.

[0061] Example 7

[0062] (1) Separation of gold and bismuth: 100 kg of bismuth-gold ore with a particle size of 38-45 μm and a content of 92% was mixed with hydrochloric acid solution obtained from the bismuth regeneration process in Example 6 and placed in a reactor. The mixture was stirred at 600 rpm at -5℃ and 500 L of concentrated hydrochloric acid was added. The liquid-solid volume mass ratio was 25:1. After reacting for 90 min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 40 g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0063] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of sodium cyanide was completed after 40 hours. According to the test and calculation, the gold leaching rate was 98.01%.

[0064] (4) Regeneration: The liquid phase 1 and gaseous hydrogen sulfide generated during the gold-bismuth separation process are transferred into a closed reaction vessel and stirred at 400 rpm for 90 min at 80 °C. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 35%, and the liquid phase is hydrochloric acid solution.

[0065] Example 8

[0066] (1) Separation of gold and bismuth: 100k bismuth-gold ore with a particle size of 38-45μm and a content of 92% was mixed with hydrochloric acid solution obtained from the bismuth regeneration process in Example 7 and placed in a reactor. The mixture was stirred at 600rpm at -5℃ without adding concentrated hydrochloric acid. The liquid-to-solid volume ratio was 25:1. After reacting for 90min, solid-liquid separation was performed to obtain gaseous hydrogen sulfide, gold concentrate and liquid phase 1. The grade of the gold concentrate in the slag phase was 38g / t. Liquid phase 1 was a mixture of bismuth chloride and hydrosulfuric acid.

[0067] (2) Gold extraction: The gold concentrate obtained in step 1 was subjected to gold extraction using the cyanide gold extraction method. The experimental process is as follows: First, the gold concentrate was diluted with water to a slurry concentration of 30%, and 30 kg / t of cyanide was added to it. 矿 Calcium oxide, after alkali leaching for 3 hours, is then supplemented with 80 kg / t of [amount missing]. 矿 The leaching of gold with sodium cyanide was completed after 40 hours. According to the test and calculation, the leaching rate of gold was 96.92%.

[0068] (3) Regeneration: The liquid phase 1 generated during the gold-bismuth separation process and the gaseous hydrogen sulfide are transferred into a closed reaction vessel and stirred at 200 rpm for 60 min at 20℃. After the reaction is completed, solid-liquid separation is performed. The slag phase bismuth concentrate has a grade of 25%, and the liquid phase is hydrochloric acid solution.

[0069] Specific implementation method two: (using sulfuric acid as the leaching agent)

[0070] A method for processing fine-grained gold ore encapsulated in bismuth sulfide includes the following steps:

[0071] (1) Bismuth removal: Bismuth-gold ore is mixed with water to form a slurry with a mass fraction of 5-30%. The slurry is placed in a reactor and reacted at 50-90°C. Then, the pH of the system is adjusted to 0.5-1.5 with 50% sulfuric acid. A certain amount of sodium chloride is added and the mixture is stirred for 90-150 min. Solid-liquid separation is then performed. The resulting slag phase is the gold concentrate, which can be used for gold extraction. The liquid phase is bismuth double salt solution 1, which is transferred to the sulfur recovery process. The hydrogen sulfide gas generated in the reaction is sent to the gas collection device.

[0072] Bi2S3+3H2SO4+6NaCl=2BiCl3+3H2S+3Na2SO4 (high temperature), H2S+2NaOH=Na2S+2H2O

[0073] (2) Sulfur recovery: Add a certain amount of calcium chloride solution to the bismuth double salt solution, with a mass fraction of 20-30%, and stir the reaction. After the reaction is completed after 30-60 minutes, solid-liquid separation is performed. The resulting slag phase is gypsum and the liquid phase is bismuth double salt solution 2, which is then transferred to the bismuth recovery process.

[0074] Na₂SO₄ + CaCl₂ = CaSO₄ + 2NaCl

[0075] (3) Bismuth recovery: Bismuth double salt solution 2 and the solution in the gas collecting bottle are both introduced into the bismuth recovery reactor. The reaction temperature is 30-60℃. After stirring for 60-120 minutes, the reaction ends and solid-liquid separation is performed. The resulting slag phase is bismuth sulfide concentrate and the liquid phase is sodium chloride solution. After evaporation and concentration of the liquid phase, concentrated sodium chloride solution and condensate are obtained. The concentrated sodium chloride solution is returned to the bismuth removal process for reuse, and the condensate can be used for slurry preparation of bismuth-gold ore or for preparing calcium oxide slurry.

[0076] 2BiCl3 + 3Na2S = Bi2S3 + 6NaCl

[0077] The above method uses sulfuric acid and sodium chloride to carry out a bismuth removal reaction on bismuth-gold ore to obtain gold concentrate. The obtained gold concentrate is then subjected to cyanide extraction, which can increase the gold leaching rate to 90-95%. The added sulfuric acid is also converted into gypsum products that can be sold. The sodium chloride used in the bismuth removal process can be regenerated and reused through the evaporation and crystallization process. The hydrogen sulfide generated in the bismuth removal process reacts with sodium hydroxide in the gas collection device to generate sodium sulfide, which is the reagent required for the bismuth recovery reaction.

[0078] Furthermore, in step (1), the bismuth-gold ore has a particle size of 38-45 μm or more, accounting for more than 90%; the bismuth grade in the bismuth-gold ore is 2-20%, and the gold grade is 5-20 g / t;

[0079] Furthermore, the molar ratio of sodium chloride to sulfuric acid in step (1) is 2 to 2.5 times. The purpose of adding sodium chloride is to prevent bismuth chloride from hydrolyzing and forming bismuth oxychloride precipitate.

[0080] Further, the stirring speed in step (1) is 300-600 rpm, and the gas collecting bottle is filled with a sodium hydroxide solution with a mass fraction of 30%.

[0081] Further, the gold concentrate grade in step (1) is 25-40 g / t, and the bismuth double salt solution 1 is a mixture of bismuth chloride and sodium sulfate;

[0082] Further, in step (2), the molar ratio of calcium chloride to sulfuric acid is 1 to 1.2; the stirring speed is 200 to 400 rpm; and the bismuth double salt solution 2 is a mixture of bismuth chloride and sodium chloride.

[0083] Furthermore, the bismuth concentrate grade in step (3) is 25-35%.

[0084] Example 9

[0085] (1) Bismuth removal: 95% bismuth-gold ore with a particle size of 45 μm was mixed with water to form a 20% slurry, which was then placed in a reactor and reacted at 70°C. The pH was adjusted to 1.0 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.2) was added. After stirring for 120 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 30 g / t and a bismuth double salt solution. The H2S gas generated in the reaction was sent to a gas collection device containing 30% NaOH.

[0086] (2) Sulfur recovery: Add 25% CaCl2 solution to bismuth double salt solution 1, stir for 45 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0087] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 45°C for 90 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 25% is obtained. The sodium chloride solution is evaporated and concentrated and then reused.

[0088] Example 10

[0089] (1) Bismuth removal: 90% bismuth-gold ore with a particle size of 40 μm was mixed with water to form a 15% slurry, which was then placed in a reactor and reacted at 80°C. The pH was adjusted to 0.8 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.0) was added. After stirring for 90 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 25 g / t and a bismuth double salt solution. The H2S gas generated in the reaction was sent to a gas collection device containing 30% NaOH.

[0090] (2) Sulfur recovery: Add 30% CaCl2 solution to bismuth double salt solution 1, stir for 50 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0091] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 55°C for 75 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 27% is obtained. The sodium chloride solution is evaporated and concentrated and then reused.

[0092] Example 11

[0093] (1) Bismuth removal: Bismuth-gold ore with a particle size of 38μm (92%) was mixed with water to form a 30% slurry, which was then placed in a reactor and reacted at 60℃. The pH was adjusted to 1.2 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.3) was added. After stirring for 150 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 40 g / t and a bismuth double salt solution. The H2S gas generated by the reaction was sent to a gas collection device containing 30% NaOH.

[0094] (2) Sulfur recovery: Add 20% CaCl2 solution to bismuth double salt solution 1, stir for 40 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0095] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 40°C for 105 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 28.9% is obtained. The sodium chloride solution is evaporated and concentrated and then reused.

[0096] Example 12

[0097] (1) Bismuth removal: Bismuth-gold ore with a particle size of 42μm (91%) was mixed with water to form a 10% slurry, which was then placed in a reactor and reacted at 85℃. The pH was adjusted to 0.9 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.1) was added. After stirring for 100 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 35 g / t and a bismuth double salt solution. The H2S gas generated by the reaction was sent to a gas collection device containing 30% NaOH.

[0098] (2) Sulfur recovery: Add 25% CaCl2 solution to bismuth double salt solution 1, stir for 35 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0099] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 50°C for 90 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 33% is obtained. The sodium chloride solution is evaporated and concentrated and then reused.

[0100] Example 13

[0101] (1) Bismuth removal: 90% bismuth-gold ore with a particle size of 39 μm was mixed with water to form a 25% slurry, which was then placed in a reactor and reacted at 75°C. The pH was adjusted to 1.1 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.4) was added. After stirring for 135 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 32 g / t and a bismuth double salt solution. The H2S gas generated in the reaction was sent to a gas collection device containing 30% NaOH.

[0102] (2) Sulfur recovery: Add 28% CaCl2 solution to bismuth double salt solution 1, stir for 55 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0103] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 58°C for 120 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 31% is obtained. The sodium chloride solution is evaporated and concentrated and then reused.

[0104] Example 14

[0105] (1) Bismuth removal: Bismuth-gold ore with a particle size of 43μm (93%) was mixed with water to form a 5% slurry, which was then placed in a reactor and reacted at 65℃. The pH was adjusted to 0.7 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.5) was added. After stirring for 110 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 38 g / t and a bismuth double salt solution. The H2S gas generated by the reaction was sent to a gas collection device containing 30% NaOH.

[0106] (2) Sulfur recovery: Add 22% CaCl2 solution to bismuth double salt solution 1, stir for 48 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0107] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 48°C for 75 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 30% is obtained. The sodium chloride solution is evaporated and concentrated and then reused.

[0108] Example 15

[0109] (1) Bismuth removal: Bismuth-gold ore with a particle size of 44μm (92%) was mixed with water to form a 12% slurry, which was then placed in a reactor and reacted at 90℃. The pH was adjusted to 1.3 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.0) was added. After stirring for 130 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 36 g / t and a bismuth double salt solution. The H2S gas generated by the reaction was sent to a gas collection device containing 30% NaOH.

[0110] (2) Sulfur recovery: Add 29% CaCl2 solution to bismuth double salt solution 1, stir for 60 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0111] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 60°C for 105 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 32.5% is obtained. The sodium chloride solution is evaporated and concentrated and then reused.

[0112] Example 16

[0113] (1) Bismuth removal: 95% bismuth-gold ore with a particle size of 41 μm was mixed with water to form an 18% slurry, which was then placed in a reactor and reacted at 55°C. The pH was adjusted to 0.6 with 50% sulfuric acid, and sodium chloride (molar ratio to sulfuric acid 2.2) was added. After stirring for 140 minutes, solid-liquid separation was performed to obtain a gold concentrate with a grade of 34 g / t and a bismuth double salt solution. The H2S gas generated by the reaction was sent to a gas collection device containing 30% NaOH.

[0114] (2) Sulfur recovery: Add 21% CaCl2 solution to bismuth double salt solution 1, stir for 42 minutes and then separate the solid and liquid to obtain gypsum and bismuth double salt solution 2.

[0115] (3) Bismuth recovery: The bismuth double salt solution 2 is reacted with the Na2S solution in the gas collecting device at 42°C for 85 minutes. After solid-liquid separation, bismuth sulfide concentrate with a grade of 35% is obtained. The sodium chloride solution is evaporated and concentrated and then returned for reuse.

Claims

1. A process for treating a fine-grained gold ore coated with bismuth sulfide, comprising: preparing a slurry of a bismuthinite ore powder containing bismuth sulfide with water; mixing the slurry with a lixiviant to cause the bismuth sulfide in the ore to react to form gaseous hydrogen sulfide, a solution containing bismuth ions, and a solid gold concentrate containing the precious metal gold; collecting the gaseous hydrogen sulfide and subsequently reacting it with the solution containing bismuth ions to form bismuth sulfide; and extracting the metallic gold from the solid gold concentrate, wherein, The leaching agent is a concentrated hydrochloric acid solution or a sulfuric acid solution added with a certain amount of sodium chloride. ​ 2. The method of claim 1, wherein, The bismuth gold ore slurry is mixed with concentrated hydrochloric acid to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and sulfuric acid, and solid gold concentrate containing precious metal gold; the mixed solution containing bismuth chloride and sulfuric acid is reacted with recovered gaseous hydrogen sulfide in a closed container to obtain bismuth sulfide concentrate and hydrogen chloride solution.

3. The method of claim 1, wherein, The bismuth gold ore slurry is mixed with a sulfuric acid solution until the pH value of the system is 0.5-1.5, and then a certain amount of sodium chloride is added to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and sodium sulfate, and solid gold concentrate containing precious metal gold; the mixed solution containing bismuth chloride and sodium sulfate is reacted with calcium chloride to obtain solid gypsum and a mixed solution containing bismuth chloride and sodium chloride; the mixed solution containing bismuth chloride and sodium chloride is introduced into a closed reaction kettle and gaseous hydrogen sulfide is introduced to perform stirring reaction at 30-60℃ for 60-120 min to obtain bismuth sulfide concentrate and sodium chloride solution.

4. The method of claim 1, wherein, The recovered gaseous hydrogen sulfide is reacted with the bismuth ion-containing solution obtained above to generate bismuth sulfide, and fresh gaseous hydrogen sulfide can be supplemented if necessary.

5. The method of claim 2, wherein, The bismuth gold ore slurry with a mass fraction of 5-30% is placed in a reactor, concentrated hydrochloric acid is added, stirring reaction is performed at -10-5℃, the liquid-solid volume-mass ratio is controlled to be 10:1-25:1, and after reaction for 60-120 min, rapid solid-liquid separation is performed to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and sulfuric acid, and solid gold concentrate containing precious metal gold; the mixed solution containing bismuth chloride and sulfuric acid is transferred into a closed reaction kettle, gaseous hydrogen sulfide is introduced, and stirring reaction is performed at 20-80℃ for 60-90 min to obtain bismuth sulfide concentrate and hydrogen chloride solution.

6. The method of claim 3, wherein, The bismuth gold ore slurry with a mass fraction of 5-30% is mixed with a 50% sulfuric acid solution until the pH value of the system is 0.5-1.5, and then sodium chloride is added, stirring reaction is performed at 50-90℃, the molar amount of sodium chloride is 2-2.5 times that of sulfuric acid, and after reaction for 90-150 min, rapid solid-liquid separation is performed to obtain gaseous hydrogen sulfide, a mixed solution containing bismuth chloride and sodium sulfate, and solid gold concentrate containing precious metal gold; the mixed solution containing bismuth chloride and sodium sulfate is reacted with a 20-30% calcium chloride solution, the molar amount of calcium chloride is 1-1.2 times that of sulfuric acid, and reaction is performed at room temperature to obtain solid gypsum and a mixed solution containing bismuth chloride and sodium chloride; the mixed solution containing bismuth chloride and sodium chloride is transferred into a closed reaction kettle, gaseous hydrogen sulfide is introduced, and stirring reaction is performed at 30-60℃ for 60-120 min to obtain bismuth sulfide concentrate and sodium chloride solution.

7. The method of claim 1, wherein, The bismuth gold ore powder has a particle size of 38-45 μm, and the particle size accounts for more than 90%; the bismuth grade is 10-20%, and the gold grade is 12-20 g / t.

8. The method of claim 1, wherein, The gold extractant is added to the solid gold concentrate to extract gold products.

9. The method of claim 2 or 3, wherein, The concentrated hydrochloric acid is recovered hydrogen chloride solution or recovered hydrogen chloride solution after adjustment; and the sodium chloride is recovered sodium chloride solution or recovered sodium chloride solution after adjustment.

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