Method for leaching and extracting gold after preoxidation of sulfide gold ore

Abstract

The invention discloses a method for extracting gold through leaching after preoxidation of sulfide gold ore, and aims to solve the problems of low recovery rate, serious environmental pollution and the like of a traditional gold extraction method. The method comprises the following steps: firstly, mixing and finely grinding the gold sulfide ore and caustic soda flakes to 325 meshes, and adjusting the concentration of ore pulp to 33%; then, oxygen-enriched air is introduced into the reaction kettle and heated to 90 DEG C, pre-oxidation treatment is carried out for 18 hours, sulfide minerals are oxidized and decomposed, and gold particles are exposed; then, adding a golden cicada environment-friendly gold extraction agent and activated carbon for leaching, continuously reacting for 18 hours to form a thiosulfate complex of gold, and adsorbing the thiosulfate complex by the activated carbon; and finally, recovering gold by filtering and analyzing electrolytic activated carbon, and performing dry discharge on tailings to prepare bricks. By implementing the method, the leaching recovery rate of gold can be remarkably increased to 97%, meanwhile, cyanide is prevented from being used, environmental pollution is reduced, comprehensive utilization of resources is achieved, and the method has the multiple advantages of being efficient, environmentally friendly, economical and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gold extraction, and particularly relates to a method for leaching gold by using gold cicada environment-friendly gold extraction agent after pre-oxidation of sulfide gold ore under heating and normal pressure. BACKGROUND

[0002] Gold ore is one of the advantageous mineral resources in China, and in particular, Carlin-type gold ore accounts for more than 30% of the gold ore in China. The gold industry reserves can reach more than 1000 tons by now, but it is one of the most difficult ores to be selected. Therefore, it is very important to seek a good method for its development and utilization.

[0003] The Carlin-type gold ore in China is mainly micro-fine disseminated sulfide gold ore. The early development of gold ore resources is mainly the surface oxidized gold ore, and the recent development is mainly the deep sulfide gold ore. The gold in the sulfide gold ore is mainly in the form of micro-fine dissemination and is wrapped by pyrite and arsenopyrite. It is difficult to be leached out by directly acting with the gold leaching agent, and needs to be pre-oxidized to destroy the wrapped minerals of gold. Only in this way, the gold can be exposed to be dissolved and leached out by the gold leaching agent. It is an extremely difficult ore to be selected.

[0004] The pre-oxidation process of sulfide gold ore has been studied more. According to the different pre-oxidation methods, it can be roughly divided into four categories, namely, roasting pre-oxidation, biological pre-oxidation, chemical pre-oxidation and hot-press pre-oxidation. The four pre-oxidation processes have advantages and disadvantages. The roasting pre-oxidation is fast and simple, but the pre-oxidation effect is greatly affected by the roasting furnace condition, and a large amount of SO2smoke and As2O3toxic smoke are generated, which causes serious environmental pollution. The biological pre-oxidation has relatively low cost, but the production cycle is long, and the leaching rate is greatly affected by the ore composition and environmental temperature. The chemical pre-oxidation has stable production process, but a large amount of chemical reagents are consumed, and harmful components such as arsenic enter the solution and need to be treated. The hot-press pre-oxidation needs to be operated under high temperature and high pressure conditions, and has high leaching rate, but has high energy consumption, high equipment requirement and low safety. The four pre-oxidation processes have been applied in industrial production in gold mines in China. The typical representative of the roasting pre-oxidation is Zimudang gold mine in Xingren County, Guizhou Province, the typical representative of the biological pre-oxidation is Lannigou gold mine in Zhenfeng County, Guizhou Province, and the typical representatives of the chemical pre-oxidation and hot-press pre-oxidation are Shuiyindong gold mine in Zhenfeng County, Guizhou Province.

[0005] The gold in the Carlin-type gold ore in China is mainly in the form of micro-fine particles, and is often wrapped by pyrite and arsenopyrite. If the structure of the carrier mineral is not destroyed, the gold is difficult to be leached out by acting with the gold cicada environment-friendly gold extraction agent.

[0006] Gold in sulfide gold ore mainly exists in the form of micro-disseminated in pyrite and arsenopyrite, which is difficult to be leached by direct action of gold leaching reagent. The existing pre-oxidation processes, such as roasting pre-oxidation, biological pre-oxidation, chemical pre-oxidation and hot-press pre-oxidation, have many problems such as serious environmental pollution, long production cycle, high energy consumption, high equipment requirement and low gold leaching recovery rate, usually only about 33%, and the comprehensive industrial production process is almost none. Overall, the existing technology is still not ideal. SUMMARY

[0007] In order to overcome the shortcomings of the prior art, the present application provides a method for leaching and extracting gold after pre-oxidation of sulfide gold ore, aiming to improve the gold leaching recovery rate and realize environmentally friendly and efficient cyanide-free leaching and gold extraction.

[0008] In order to achieve the above-mentioned purpose, the present application realizes the following technical scheme:

[0009] A method for leaching and extracting gold after pre-oxidation of sulfide gold ore, comprising the following steps:

[0010] S1: mixing and fine grinding sulfide gold ore and flake alkali in proportion to 325 mesh;

[0011] S2: adjusting the concentration of the fine ground ore slurry to 33%;

[0012] S3: in a stirring state, using a Roots blower to introduce oxygen-rich air into the ore slurry, the oxygen flow rate is 13 m 3 / h;

[0013] S4: heating the ore slurry to 90℃ and pre-oxidizing for 18 hours; then adding gold cicada environment-friendly gold extraction agent and activated carbon, and continuing to leach for 18 hours, the total treatment time is 36 hours, wherein the addition amount of cicada environment-friendly gold extraction agent is 2 kg per ton of ore, and the activated carbon is 8-12 mesh coarse particles, accounting for 4% of the mass fraction of the ore slurry;

[0014] S5: after the leaching is completed, filtering the ore slurry, resolving and electrolyzing the activated carbon to recover gold, and dry-discharging the tailings to make bricks.

[0015] Further, in the fine grinding step, the addition amount of flake alkali is 4 kg per ton of ore.

[0016] Further, in the pre-oxidation process, the synergistic effect of heating and oxygen-rich air promotes the oxidative decomposition of sulfide minerals to generate thiosulfate, so that the gold particles are exposed.

[0017] Further, in the leaching step, the gold cicada environment-friendly gold extraction agent reacts with the exposed gold particles to form thiosulfate complex of gold, realizing cyanide-free leaching of gold.

[0018] Furthermore, the method also includes filtering the leached slurry and electrolytic desorption of activated carbon to recover gold; meanwhile, the tailings are dried and used for brick making.

[0019] Furthermore, the method significantly improves the gold leaching recovery rate in sulfide gold ore to 97% through the synergistic effect of fine grinding, heating, oxygen-enriched pre-oxidation, and leaching with Jinchan environmentally friendly gold extraction agent.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] Improved recovery rate: Through the synergistic effect of fine grinding, pre-oxidation by heating and leaching with Jinchan environmentally friendly gold extraction agent, the gold leaching recovery rate has been increased from the original 33% to 97%.

[0022] Environmentally friendly and efficient: The gold extraction method uses cyanide-free leaching, which avoids the use of cyanide and reduces environmental pollution.

[0023] Comprehensive utilization of resources: After dry discharge treatment, tailings can be used for brick making, realizing comprehensive utilization of resources.

[0024] In summary, this invention provides an environmentally friendly, efficient, and resource-integrated method for leaching gold from sulfide gold ore after pre-oxidation, which has broad application prospects and significant economic value. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the implementation of a method for leaching gold from sulfide gold ore after pre-oxidation, according to the present invention. Detailed Implementation

[0026] The present invention will now be described in more detail and in more complete form with reference to the accompanying drawings.

[0027] This invention provides a method for leaching gold from sulfide gold ore after pre-oxidation.

[0028] I. Implementation Steps

[0029] (1) Raw material preparation and fine grinding

[0030] We select ores containing gold sulfide as raw materials to ensure that the gold content in the ore reaches economic mining value.

[0031] Mix the gold sulfide ore with caustic soda (NaOH) at a ratio of 4 kg per ton of ore until homogeneous;

[0032] The mixed ore was finely ground to 325 mesh (-0.038 mm) using a ball mill to ensure that the ore particles were small enough to facilitate subsequent pre-oxidation and leaching steps.

[0033] (2) Adjusting the pulp concentration

[0034] The finely ground ore is mixed with water, and the concentration of the slurry is adjusted to 33%. This can be achieved by measuring the solids content of the slurry and making appropriate adjustments.

[0035] (3) Introducing oxygen-enriched air

[0036] Place the adjusted slurry into a reactor equipped with a stirring device;

[0037] Turn on the Roots blower and introduce oxygen-enriched air into the reactor, controlling the oxygen flow rate at 13 m³ / min. 3 / h. The mixing device continuously agitates the slurry to ensure sufficient contact between oxygen and the slurry.

[0038] (4) Heating pre-oxidation treatment

[0039] Turn on the heating device of the reactor to heat the slurry to 90°C;

[0040] Maintain this temperature and perform a pre-oxidation treatment for 18 hours. During this period, the sulfide minerals undergo oxidative decomposition under heating and oxygen-rich conditions to generate thiosulfates, gradually exposing the encapsulated gold grains.

[0041] (5) Golden Cicada Environmental Gold Extraction Agent Leaching

[0042] After the pre-oxidation treatment is completed, add Jinchan environmentally friendly gold extraction agent to the reactor at a dosage of 2 kg / t ore.

[0043] At the same time, activated carbon (8-12 mesh) is added at a rate of 4% of the slurry mass fraction. The activated carbon is used to adsorb the leached gold.

[0044] Continue stirring and maintain the temperature for 18 hours of leaching. During this period, the Jinchan environmentally friendly gold extraction agent reacts with the exposed gold particles to form gold thiosulfate complexes, which are then adsorbed by activated carbon.

[0045] (6) Post-processing and gold recovery

[0046] After leaching is complete, turn off the heating and stirring devices and allow the slurry to cool naturally.

[0047] The slurry was filtered using a filtration device to separate the gold-containing activated carbon.

[0048] The activated carbon is subjected to analytical electrolytic treatment to recover the gold.

[0049] Tailings, after being dried and discharged, can be used to make bricks or other building materials, thus achieving comprehensive utilization of resources.

[0050] II. Implementation Results

[0051] Through the above-described specific implementation methods, gold can be successfully extracted from sulfide gold ore, and the gold leaching recovery rate can reach 97%. Furthermore, this method also has the following advantages:

[0052] Environmentally friendly: The gold extraction method using cyanide-free leaching avoids the use of cyanide and reduces environmental pollution.

[0053] High efficiency: Through the synergistic effect of fine grinding, pre-oxidation by heating, and leaching with Jinchan environmentally friendly gold extraction agent, high-efficiency gold extraction is achieved.

[0054] Comprehensive utilization of resources: Tailings can be used for brick making after dry discharge treatment, realizing comprehensive utilization of resources and reduction of waste.

[0055] The above implementation methods are merely examples. In actual implementation, adjustments may be necessary based on the specific ore properties, equipment conditions, and production requirements. However, by following the basic principles and steps of this invention, efficient and environmentally friendly gold extraction from sulfide gold ore can be successfully achieved.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for gold extraction from a sulfidic gold ore after pre-oxidation and leaching, characterized in that, The method comprises the following steps: S1: mixing and finely grinding sulfide gold ore and flake alkali in proportion to 325 mesh; S2: adjusting the concentration of the finely ground ore slurry to 33%; S3: In the state of stirring, the oxygen-enriched air is introduced into the ore pulp by using Roots blower, and the oxygen flow is 13 m 3 / h; S4: heating the ore slurry to 90℃ and performing pre-oxidation treatment for 18 hours; then adding gold cicada environment-friendly gold extraction agent and activated carbon and continuing leaching for 18 hours, with a total treatment time of 36 hours, wherein the addition amount of the cicada environment-friendly gold extraction agent is 2 kg per ton of ore, the activated carbon is 8-12 mesh coarse particles, and the mass fraction of the activated carbon in the ore slurry is 4%; S5: after the leaching is completed, filtering the ore slurry, resolving and electrolyzing the activated carbon to recover gold, and dry-discharging the tailings for brick making.

2. A method for gold extraction by leaching of pre-oxidized sulphidic gold ores according to claim 1, characterized in that: In the fine grinding step, the addition amount of the flake alkali is 4 kg per ton of ore.

3. A method for gold extraction by leaching of pre-oxidized sulphidic gold ores according to claim 1, characterized in that: In the pre-oxidation treatment process, through the synergistic effect of heating and oxygen-enriched air, the oxidation and decomposition of sulfide minerals are promoted, and thiosulfate is generated to expose the wrapped gold particles.

4. The method for gold extraction from pre-oxidized sulfidic gold ores by leaching according to claim 1, characterized in that: In the leaching step, the gold cicada environment-friendly gold extraction agent reacts with the exposed gold particles to form a gold thiosulfate complex, achieving cyanide-free leaching of gold.

5. A method for gold extraction by leaching of pre-oxidized sulphidic gold ores according to claim 1, characterized in that: The method further comprises the steps of filtering the ore slurry after leaching and resolving and electrolyzing the activated carbon to recover gold; at the same time, the tailings are dry-discharged for brick making.

6. A method of gold extraction by leaching of pre-oxidized sulphidic gold ores according to any one of claims 1 to 5, characterized by: The method significantly improves the leaching recovery rate of gold in sulfide gold ore through the synergistic effect of fine grinding, heating, oxygen-enriched pre-oxidation, and gold cicada environment-friendly gold extraction agent leaching, reaching 97%.

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