Gold smelting production process

Abstract

The invention discloses a gold smelting production process. The gold smelting production process specifically comprises the following steps: (1) ore pretreatment; (2) flotation; (3) smelting; (4) refining; and (5) treating wastewater and waste gas. According to the efficient and environment-friendly gold smelting production process, by optimizing the key steps of ore pretreatment, flotation, smelting, refining, waste water and waste gas treatment and the like, the gold smelting efficiency is improved, the production cost is reduced, and environmental pollution is reduced; and reference can be provided for other precious metal smelting fields.

Description

Technical Field

[0001] The present invention relates to the technical field of precious metal smelting, and more specifically to a gold smelting production process. Background Art

[0002] The traditional gold smelting production process has problems such as high energy consumption, serious environmental pollution, and high production costs. Especially in the links of ore pretreatment, smelting, refining, and wastewater and waste gas treatment, it not only consumes a lot of energy, but also may produce a lot of dust, harmful gases and wastewater, posing a threat to the environment and human health. Therefore, the development of an efficient, environmentally friendly and process-optimized gold smelting production process has become a technical problem that needs to be solved urgently in the current field of precious metal smelting.

[0003] For a long time, gold extraction has mainly relied on the traditional amalgamation method or cyanidation method. Although these methods can achieve gold extraction to a certain extent, they have many limitations. For example, the amalgamation method produces a large amount of wastewater and waste residue during the treatment process, causing serious environmental pollution. The cyanidation method has safety risks in the use and discharge of cyanide, and the leaching speed is relatively slow, and the adaptability to ores is limited.

[0004] In order to solve the problems of traditional refining technology, modern refining technology came into being. These technologies not only improve the recovery rate of gold, but also reduce environmental pollution and safety risks. At present, the main modern refining technologies are:

[0005] 1. Thiosulfate leaching method: Using thiosulfate as a leaching agent, gold is dissolved from the ore through chemical reaction. This method has the advantages of being environmentally friendly and having high leaching efficiency.

[0006] 2. Thiourea leaching method: Thiourea is also an effective leaching agent, which can achieve efficient leaching of gold at lower temperature and pressure.

[0007] 3. Resin adsorption method: Resins with high adsorption capacity and selectivity are used as adsorbents to adsorb gold from the solution through physical or chemical action. This method has the advantages of simple operation and high recovery rate.

[0008] 4. Activated carbon adsorption method: Activated carbon is widely used in gold recovery due to its good adsorption properties. Through the adsorption of activated carbon, effective recovery of gold can be achieved.

[0009] 5. Electrolysis: Through the electrolysis process, gold can be precipitated from the solution to obtain high-purity gold. This method has the advantages of high purification efficiency and simple operation, and is an efficient method for gold purification.

[0010] However, modern refining technology still has problems such as low smelting efficiency, high production costs, and environmental pollution.

[0011] Therefore, how to further optimize the production process of gold smelting is an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0012] In view of this, the object of the present invention is to provide a gold smelting production process to solve the deficiencies in the prior art.

[0013] In order to achieve the above object, the present invention adopts the following technical solution:

[0014] A gold smelting production process specifically comprises the following steps:

[0015] (1) Ore pretreatment

[0016] First, the original gold ore is crushed and screened to obtain ore particles with uniform particle size; then water and environmentally friendly abrasives are added to perform wet grinding to obtain ore fine slurry;

[0017] (2) Flotation

[0018] The ore fine pulp is sent to the hydrocyclone for classification, and then subjected to preferential flotation, rough separation by the first-stage flotation column, fine separation by the third-stage flotation column, and scavenging separation by the flotation machine to obtain the ore fine pulp after flotation;

[0019] (3) Smelting

[0020] The fine ore pulp after flotation is sent to the smelting furnace for oxygen-free or low-oxygen smelting to obtain crude gold;

[0021] (4) Refining

[0022] The crude gold is electrochemically refined to obtain gold;

[0023] (5) Wastewater and waste gas treatment

[0024] Treatment of wastewater and waste gas generated during smelting and refining processes.

[0025] Furthermore, in the above step (1), the crushing equipment is a jaw crusher or a cone crusher; the screening equipment is a vibrating screen; the environmentally friendly abrasive is a ceramic abrasive, which is prepared by mixing 60%-80% aluminum oxide (Al2O3) and 20%-40% zirconium oxide (ZrO2) by mass percentage, or by mixing 20%-80% silicon nitride (Si3N4) and 20%-80% aluminum oxide (Al2O3, obtained by calcining aluminum hydroxide Al(OH)3), and the specific proportion is adjusted according to the required particle size, grinding efficiency and wear resistance; the wet grinding equipment is a wet grinder; and ultrasonic assisted grinding is performed during the wet grinding process.

[0026] Furthermore, the ultrasonic frequency of the ultrasonic assisted grinding is 20-40kHz, and the time is adjusted according to the properties and particle size requirements of the ore, generally 1-3h.

[0027] A further beneficial effect of the above is that, during the wet refining process, adding water and environmentally friendly abrasives can reduce dust pollution. Among them, ceramic-based abrasives not only have good grinding performance and are durable, but are also generally non-toxic and do not release harmful substances during the grinding process, which is environmentally friendly. During the wet refining process, the introduction of ultrasonic assisted grinding technology can improve the dispersion and grinding efficiency of ore particles through the cavitation effect and acceleration effect of ultrasonic waves.

[0028] Furthermore, in the above step (2), the flotation column is a multi-stage cyclone microbubble flotation column with a diameter of 5.5 m, and pressure filtration dehydration recovery is adopted; the flotation machine can be a four-slot flotation machine or a five-slot flotation machine according to different process requirements.

[0029] Furthermore, in the above step (3), during the smelting process, the waste heat recovery system is used to recover the heat energy generated by the smelting, which is used to preheat the next batch of original gold ore or for use in other production links; an intelligent temperature control system is introduced into the smelting furnace to automatically adjust the furnace temperature and oxygen content according to the temperature changes during the smelting process; and the extract is placed in an ultra-gravity centrifugal extractor to extract the gold solution.

[0030] Furthermore, the temperature control range of the above-mentioned intelligent temperature control system is 1000-1500°C, and the oxygen content control range is 0.5%-5%; the extraction liquid is at least one of methyl isobutyl ketone (MIBK), dibutyl carbonate (DBC), octanol and ionic liquid, and multi-stage extraction can be used to improve the recovery rate; the ionic liquid is 1-ethyl-3-methylimidazole acetate or 1,3-dimethylimidazole dimethyl phosphate; the ultra-gravity centrifugal extractor is a high-speed ratio, multi-wire mesh winding extractor.

[0031] The above further beneficial effect is that the use of oxygen-free or low-oxygen smelting technology can reduce the emission of harmful gases. The extraction rate of gold by the extracting liquid selected by the present invention can reach more than 99%. The large number of wire mesh structures inside the ultra-gravity centrifugal extractor can effectively improve the extraction efficiency and can increase the gold recovery rate to more than 99%.

[0032] Furthermore, in the above step (4), during the refining process, a multi-stage filtration system is introduced into the electrolytic cell.

[0033] Furthermore, the multi-stage filtration system includes at least two stages of filtration devices, the first stage is a coarse filtration device, and the second stage is a fine filtration device.

[0034] The above further beneficial effect is that the electrochemical refining technology is used to separate gold from other impurities by the action of electric current, which can improve the purity and quality of gold. The introduction of a multi-stage filtration system can effectively remove impurities and particulate matter in the electrolyte, wherein the first-stage coarse filtration device can remove large particles in the electrolyte, and the second-stage fine filtration device can remove tiny particles and impurities in the electrolyte.

[0035] Furthermore, in the above step (5), the wastewater is passed into a membrane bioreactor (MBR) for biological treatment and then chemical treatment; the waste gas is passed into a high-efficiency dust collector for dust removal and then passed into a desulfurization and denitrification device for desulfurization and denitrification.

[0036] Furthermore, the above-mentioned membrane bioreactor uses high-temperature-resistant and corrosion-resistant polymer materials such as carbon fiber to prepare high-toughness and high-strength hollow fiber membranes with a membrane pore size of 0.01-0.1μm, forming liquid membrane voids in the membrane voids that are suitable for the growth of nitrifying bacteria.

[0037] The further beneficial effect of adopting the above method is that the wastewater and waste gas generated during the smelting and refining process are specially treated to remove harmful substances therein and meet environmental emission standards. The membrane bioreactor selected by the present invention can effectively remove suspended matter, organic matter (sulfur and nitrogen compounds) and microorganisms in wastewater, and the biofilm is a liquid membrane and is easy to regenerate. It only needs to immerse the dry biofilm in a special biological culture solution and wait for the gaps in the biofilm to be filled with liquid before it can be used again. The dust removal efficiency of the high-efficiency dust collector selected by the present invention is not less than 99%, and the desulfurization efficiency and denitrification efficiency of the desulfurization and denitrification device are not less than 90% and 85% respectively.

[0038] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] The present invention provides an efficient and environmentally friendly gold smelting production process, which improves the gold smelting efficiency, reduces the production cost and reduces environmental pollution by optimizing key steps such as ore pretreatment, flotation, smelting, refining and wastewater and waste gas treatment. It is not only suitable for the gold smelting industry, but also can provide reference and reference for other precious metal smelting fields. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] The gold smelting production process specifically includes the following steps:

[0043] (1) Ore pretreatment

[0044] First, the original gold ore is added to a jaw crusher or a cone crusher for crushing, and then added to a vibrating screen for screening to obtain ore particles with uniform particle size; then water and an environmentally friendly abrasive are added, wherein the environmentally friendly abrasive is prepared by mixing 30% silicon nitride and 70% aluminum oxide, and the addition amount is 5g / g gold; finally, an ultrasonic wave with a frequency of 20kHz is used in a wet pulping machine to assist wet pulping for 3 hours to obtain a fine ore pulp;

[0045] (2) Flotation

[0046] The ore slurry is sent to the hydrocyclone for classification, and then subjected to preferential flotation, roughing by the first-stage flotation column, and fine separation by the third-stage flotation column. The flotation column is a multi-stage hydrocyclone microbubble flotation column with a diameter of 5.5m. It adopts pressurized filtration, dehydration and recovery, and scavenging by a four-slot flotation machine to obtain the ore slurry after flotation.

[0047] (3) Smelting

[0048] The fine ore pulp after flotation is sent to the smelting furnace for oxygen-free or low-oxygen smelting. During the smelting process, the waste heat recovery system is used to recover the heat energy generated by smelting and use it to preheat the next batch of original gold ore; an intelligent temperature control system is introduced into the smelting furnace to automatically adjust the furnace temperature to 1000°C and the oxygen content to 5% according to the temperature changes during the smelting process; the extracting liquid 2-octanol is placed in a high-speed ratio, multi-wire mesh winding ultra-gravity centrifugal extractor to extract the gold solution to obtain crude gold;

[0049] (4) Refining

[0050] The crude gold is subjected to electrochemical refining. During the refining process, a multi-stage filtration system including a coarse filtration device and a fine filtration device is introduced into the electrolytic cell to obtain gold;

[0051] (5) Wastewater and waste gas treatment

[0052] The wastewater and waste gas generated during the smelting and refining process are treated. The wastewater is passed through a hollow fiber membrane made of carbon fiber and a membrane bioreactor with a pore size of 0.01μm for biological treatment, and then chemically treated; the waste gas is passed through a high-efficiency dust collector for dust removal, and then passed through a desulfurization and denitrification device for desulfurization and denitrification.

[0053] Example 2

[0054] The gold smelting production process specifically includes the following steps:

[0055] (1) Ore pretreatment

[0056] First, the original gold ore is added to a jaw crusher or a cone crusher for crushing, and then added to a vibrating screen for screening to obtain ore particles with uniform particle size; then water and an environmentally friendly abrasive are added, wherein the environmentally friendly abrasive is prepared by mixing 20% ​​silicon nitride and 80% aluminum oxide, and the addition amount is 8g / g gold; finally, an ultrasonic wave with a frequency of 30kHz is used in a wet pulping machine to assist wet pulping for 2 hours to obtain a fine ore pulp;

[0057] (2) Flotation

[0058] The ore slurry is sent to the hydrocyclone for classification, and then subjected to preferential flotation, roughing by the first-stage flotation column, and fine separation by the third-stage flotation column. The flotation column is a multi-stage hydrocyclone microbubble flotation column with a diameter of 5.5m. It is dehydrated and recycled by pressure filtration, and swept by a five-slot flotation machine to obtain the ore slurry after flotation.

[0059] (3) Smelting

[0060] The fine ore pulp after flotation is sent to the smelting furnace for oxygen-free or low-oxygen smelting. During the smelting process, the waste heat recovery system is used to recover the heat energy generated by the smelting and use it to preheat the next batch of original gold ore; an intelligent temperature control system is introduced into the smelting furnace to automatically adjust the furnace temperature to 1200°C and the oxygen content to 3% according to the temperature changes during the smelting process; the extract 1-ethyl-3-methylimidazole acetate is placed in a high-speed ratio, multi-wire mesh winding ultra-gravity centrifugal extractor to extract the gold solution to obtain crude gold;

[0061] (4) Refining

[0062] The crude gold is subjected to electrochemical refining. During the refining process, a multi-stage filtration system including a coarse filtration device and a fine filtration device is introduced into the electrolytic cell to obtain gold;

[0063] (5) Wastewater and waste gas treatment

[0064] The wastewater and waste gas generated during the smelting and refining process are treated. The wastewater is passed through a hollow fiber membrane made of carbon fiber and a membrane bioreactor with a pore size of 0.05μm for biological treatment, and then chemically treated; the waste gas is passed through a high-efficiency dust collector for dust removal, and then passed through a desulfurization and denitrification device for desulfurization and denitrification.

[0065] Example 3

[0066] The gold smelting production process specifically includes the following steps:

[0067] (1) Ore pretreatment

[0068] First, the original gold ore is added to a jaw crusher or a cone crusher for crushing, and then added to a vibrating screen for screening to obtain ore particles with uniform particle size; then water and an environmentally friendly abrasive are added, wherein the environmentally friendly abrasive is prepared by mixing 50% silicon nitride and 50% aluminum oxide, and the addition amount is 5g / g gold; finally, an ultrasonic wave with a frequency of 40kHz is used in a wet pulping machine to assist wet pulping for 1 hour to obtain a fine ore pulp;

[0069] (2) Flotation

[0070] The ore slurry is sent to the hydrocyclone for classification, and then subjected to preferential flotation, roughing by the first-stage flotation column, and fine separation by the third-stage flotation column. The flotation column is a multi-stage hydrocyclone microbubble flotation column with a diameter of 5.5m. It is dehydrated and recycled by pressure filtration, and swept by a five-slot flotation machine to obtain the ore slurry after flotation.

[0071] (3) Smelting

[0072] The fine ore pulp after flotation is sent to the smelting furnace for oxygen-free or low-oxygen smelting. During the smelting process, the waste heat recovery system is used to recover the heat energy generated by the smelting and use it to preheat the next batch of original gold ore; an intelligent temperature control system is introduced into the smelting furnace to automatically adjust the furnace temperature to 1500°C and the oxygen content to 0.5% according to the temperature changes during the smelting process; the extract 1,3-dimethylimidazole dimethyl phosphate is placed in a high-speed ratio, multi-wire mesh winding ultra-gravity centrifugal extractor to extract the gold solution to obtain crude gold;

[0073] (4) Refining

[0074] The crude gold is subjected to electrochemical refining. During the refining process, a multi-stage filtration system including a coarse filtration device and a fine filtration device is introduced into the electrolytic cell to obtain gold;

[0075] (5) Wastewater and waste gas treatment

[0076] The wastewater and waste gas generated during the smelting and refining process are treated. The wastewater is passed through a hollow fiber membrane made of carbon fiber and a membrane bioreactor with a pore size of 0.1μm for biological treatment, and then chemically treated; the waste gas is passed through a high-efficiency dust collector for dust removal, and then passed through a desulfurization and denitrification device for desulfurization and denitrification.

[0077] Performance Testing

[0078] A batch of original gold ore from a certain place is divided into three parts on average, and gold is smelted according to the production processes of Examples 1-3 respectively, and the gold extraction rate, gold recovery rate, dust removal efficiency, desulfurization efficiency, denitrification efficiency and production cost are calculated respectively.

[0079] The results are shown in Table 1.

[0080] Table 1 Performance test results of the production process of Examples 1-3

[0081] Production process Gold extraction rate Gold recovery rate Dust removal efficiency Desulfurization efficiency Denitrification efficiency Production costs Example 1 99.1% 99.8% 99.5% 93% 95% 0.9 billion yuan / ton Example 2 99.5% 99.6% 99.3% 91% 90% 0.99 billion yuan / ton Example 3 99.7% 99.2% 99.0% 90% 85% 105 million yuan / ton

[0082] It can be seen from Table 1 that the gold extraction rate, gold recovery rate and dust removal efficiency of the production process of Examples 1-3 are all above 99%, the desulfurization efficiency and denitrification efficiency are not less than 90% and 85% respectively, and the production cost is not higher than 105 million yuan / ton.

[0083] The above experiments show that the present invention provides an efficient and environmentally friendly gold smelting production process. By optimizing key steps such as ore pretreatment, flotation, smelting, refining, and wastewater and exhaust gas treatment, the gold smelting efficiency is improved, the production cost is reduced, and environmental pollution is reduced. It is not only suitable for the gold smelting industry, but also can provide reference and reference for other precious metal smelting fields.

[0084] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A gold smelting production process, characterized in that: The specific steps include: (1) Ore pretreatment First, the original gold ore is crushed and screened to obtain ore particles with uniform particle size; then water and environmentally friendly abrasives are added to perform wet grinding to obtain ore fine slurry; (2) Flotation The ore fine pulp is sent to the hydrocyclone for classification, and then subjected to preferential flotation, rough separation by the first-stage flotation column, fine separation by the third-stage flotation column, and scavenging separation by the flotation machine to obtain the ore fine pulp after flotation; (3) Smelting The fine ore pulp after flotation is sent to the smelting furnace for oxygen-free or low-oxygen smelting to obtain crude gold; (4) Refining Electrochemically refining the crude gold to obtain the gold; (5) Wastewater and waste gas treatment Treatment of wastewater and waste gas generated during smelting and refining processes.

2. A gold smelting production process according to claim 1, characterized in that: In step (1), the crushing equipment is a jaw crusher or a cone crusher; the screening equipment is a vibrating screen; the environmentally friendly abrasive is a ceramic abrasive, which is prepared by mixing 60%-80% alumina and 20%-40% zirconium oxide, or by mixing 20%-80% silicon nitride and 20%-80% alumina, in terms of mass percentage; the wet grinding equipment is a wet grinder; and ultrasonic-assisted grinding is performed during the wet grinding process.

3. A gold smelting production process according to claim 2, characterized in that: The ultrasonic frequency of the ultrasonic assisted grinding is 20-40 kHz, and the time is 1-3 hours.

4. A gold smelting production process according to claim 1, characterized in that: In step (2), the flotation column is a multi-stage cyclone microbubble flotation column with a diameter of 5.5 m, and pressure filtration and dehydration recovery are adopted; the flotation machine is a four-slot flotation machine or a five-slot flotation machine.

5. A gold smelting production process according to claim 1, characterized in that: In step (3), during the smelting process, the waste heat recovery system is used to recover the heat energy generated by the smelting, which is used to preheat the next batch of original gold ore or for use in other production links; an intelligent temperature control system is introduced into the smelting furnace to automatically adjust the furnace temperature and oxygen content according to the temperature changes during the smelting process; and the extract is placed in an ultra-gravity centrifugal extractor to extract the gold solution.

6. A gold smelting production process according to claim 5, characterized in that: The temperature control range of the intelligent temperature control system is 1000-1500°C, and the oxygen content control range is 0.5%-5%; the extracting liquid is at least one of methyl isobutyl ketone, dibutyl carbonate, octanol and ionic liquid; the ionic liquid is 1-ethyl-3-methylimidazole acetate or 1,3-dimethylimidazole dimethyl phosphate; the ultra-gravity centrifugal extractor is a high-speed ratio, multi-wire mesh winding extractor.

7. The gold smelting production process according to claim 1, characterized in that: In step (4), during the refining process, a multi-stage filtration system is introduced into the electrolytic cell.

8. A gold smelting production process according to claim 7, characterized in that: The multi-stage filtering system comprises at least two stages of filtering devices, the first stage is a coarse filtering device, and the second stage is a fine filtering device.

9. The gold smelting production process according to claim 1, characterized in that: In step (5), the wastewater is passed into a membrane bioreactor for biological treatment and then chemical treatment; the waste gas is passed into a high-efficiency dust collector for dust removal and then passed into a desulfurization and denitrification device for desulfurization and denitrification.

10. A gold smelting production process according to claim 9, characterized in that: The membrane bioreactor adopts a hollow fiber membrane made of carbon fiber, and the membrane pore diameter is 0.01-0.1 μm.