A method for leaching and extracting gold from low-grade gold ores

Abstract

This invention relates to the field of low-grade gold ore processing technology, and more particularly to a method for extracting gold from low-grade gold ore through leaching. The invention provides a method for extracting gold from low-grade gold ore through leaching, comprising the following steps: sequentially crushing, roasting, grinding, and magnetic separation of the low-grade gold ore to obtain gold-rich powder and gold-poor powder; mixing the gold-rich powder with sodium cyanide solution, lime, and functional activated carbon, and extracting through leaching under oxygen and alkaline conditions; and mixing the gold-poor powder with sodium cyanide solution, lime, and activated carbon, and extracting through leaching under oxygen and alkaline conditions. This invention provides a method for extracting gold from low-grade gold ore through leaching. Targeting the composition, structure, and physicochemical characteristics of low-grade gold ore, this invention achieves high gold recovery rates, controllable costs, good process stability, and significant economic and social benefits by employing a comprehensive process including specific pretreatment, leaching extraction reagents, and subsequent treatments.

Description

Technical Field

[0001] This invention relates to the field of low-grade gold ore processing technology, and in particular to a method for extracting gold from low-grade gold ore by leaching. Background Technology

[0002] Low-grade gold ore refers to ore with a gold content below the standard for traditional economic mining, typically less than 0.5 grams per ton. Low-grade gold ore constitutes a relatively high proportion of gold deposits; therefore, effectively processing low-grade gold ore to extract gold is of great significance for the full utilization of gold resources.

[0003] The challenges of extracting gold from low-grade gold mines are not limited to the low gold content; they also include the gold's form and interference from other minerals. For example, gold in low-grade gold mines often exists as extremely fine particles (even microscopic gold), tightly encased by sulfides or gangue minerals such as pyrite and arsenopyrite. Associated minerals in low-grade gold mines, such as pyrrhotite and chalcopyrite, consume large amounts of cyanide and dissolved oxygen in extraction reagents, preventing the target gold mineral from reacting fully and resulting in low gold recovery rates.

[0004] Therefore, developing a method for high-recovery gold extraction from low-grade gold ore, taking into account its characteristics, is of significant technical and economic importance. Summary of the Invention

[0005] In view of this, the present invention provides a method for extracting gold from low-grade gold ore by infiltration, which can extract gold from low-grade gold ore with high recovery rate.

[0006] This invention provides a method for extracting gold from low-grade gold ore by leaching, comprising the following steps: (1) The low-grade gold ore is crushed, roasted, ground and magnetically separated in sequence to obtain gold-rich powder and gold-poor powder; (2) The gold-rich powder, sodium cyanide solution, lime and functional activated carbon are mixed and extracted under oxygen and alkaline conditions; (3) The gold powder, sodium cyanide solution, lime and activated carbon are mixed and extracted under oxygen and alkaline conditions.

[0007] Preferably, the roasting includes a first roasting, a second roasting, and a third roasting performed sequentially; the first roasting temperature is 400-550 degrees Celsius, and the holding time is 30-50 minutes; the first roasting is carried out under oxygen-enriched conditions, wherein the oxygen volume concentration of the oxygen-enriched conditions is 50-52%; the second roasting temperature is 600-650 degrees Celsius, and the holding time is 30-50 minutes; the second roasting is carried out under oxygen-containing conditions, wherein the oxygen volume concentration of the oxygen-containing conditions is 20-25%; the third roasting temperature is 750-800 degrees Celsius, and the holding time is 50-80 minutes; the third roasting is carried out under oxygen-containing conditions, wherein the oxygen volume concentration of the oxygen-containing conditions is 38-45%.

[0008] Preferably, the target particle size for grinding is: the proportion of particles with a diameter of less than 35 micrometers is more than 65%.

[0009] Preferably, the magnetic separation includes a first magnetic separation and a second magnetic separation performed sequentially; the magnetic field strength of the first magnetic separation is 950~1250mT; and the magnetic field strength of the second magnetic separation is 900~1100mT.

[0010] Preferably, the preparation method of the functional activated carbon includes the following steps: activating activated carbon by mixing it with an aqueous solution of potassium hydroxide to obtain modified activated carbon; and heat-treating the modified activated carbon, potassium oxalate, and epichlorohydrin to obtain the functional activated carbon.

[0011] Preferably, the activation temperature is 150-160 degrees Celsius, and the holding time is 1-3 hours.

[0012] Preferably, the mass ratio of the modified activated carbon to potassium oxalate is 1:0.3~0.5; and the mass ratio of the modified activated carbon to epichlorohydrin is 1:0.8~1.2.

[0013] Preferably, the heat treatment temperature is 600-700 degrees Celsius, and the holding time is 3-5 hours.

[0014] Preferably, in step (2), the mixing includes the following steps: mixing lime and gold-rich powder to form a pile, then spraying sodium cyanide solution into the gold-rich mineral pile for heap leaching, then separating the solid and liquid phases to collect the liquid phase, and then mixing the liquid phase with functional activated carbon for adsorption.

[0015] Preferably, in step (3), the mixing includes the following steps: mixing lime and gold-poor powder to form a pile, then spraying sodium cyanide solution into the gold-poor mineral pile for heap leaching, then separating the solid and liquid phases to collect the liquid phase, and then mixing the liquid phase with activated carbon for adsorption.

[0016] Compared with the prior art, the present invention has achieved the following beneficial effects: This invention provides a method for extracting gold from low-grade gold ore through leaching. Targeting the composition, structure, and physicochemical properties of low-grade gold ore, this invention achieves high gold recovery rates, controllable costs, good process stability, and significant economic and social benefits by employing a comprehensive process including specific pretreatment, leaching extraction reagents, and subsequent treatments. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of this invention, the accompanying drawings used in the embodiments of this invention or in the prior art are briefly described below. For those skilled in the art, other drawings can be derived from the following drawings without creative effort, and all such drawings are within the protection scope of this invention.

[0018] Figure 1 The graph shows a comparison of the recovery rates of Examples 1-4 and Comparative Examples 1-4. Detailed Implementation

[0019] This invention provides a method for extracting gold from low-grade gold ore by leaching, comprising the following steps: (1) The low-grade gold ore is crushed, roasted, ground and magnetically separated in sequence to obtain gold-rich powder and gold-poor powder; (2) The gold-rich powder, sodium cyanide solution, lime and functional activated carbon are mixed and extracted under oxygen and alkaline conditions; (3) The gold powder, sodium cyanide solution, lime and activated carbon are mixed and extracted under oxygen and alkaline conditions.

[0020] This invention involves sequentially crushing, roasting, grinding, and magnetic separation of low-grade gold ore to obtain gold-rich powder and gold-poor powder. In this invention, the target particle size for crushing is preferably 1-8 mm, more preferably 1-5 mm.

[0021] In this invention, the roasting preferably includes a first roasting, a second roasting, and a third roasting performed sequentially; the temperature of the first roasting is preferably 400-550 degrees Celsius, more preferably 450-500 degrees Celsius, and the holding time is preferably 30-50 minutes, more preferably 40 minutes; the first roasting is preferably carried out under oxygen-enriched conditions, wherein the oxygen volume concentration under the oxygen-enriched conditions is preferably 50-52%; the temperature of the second roasting is preferably 600-650 degrees Celsius, more preferably 620 degrees Celsius, and the holding time is preferably 30-50 minutes, more preferably 35 minutes; the second roasting is preferably carried out under oxygen-containing conditions, wherein the oxygen volume concentration under the oxygen-containing conditions is preferably 20-25%; the temperature of the third roasting is preferably 750-800 degrees Celsius, more preferably 770 degrees Celsius, and the holding time is preferably 50-80 minutes, more preferably 60-70 minutes; the third roasting is preferably carried out under oxygen-containing conditions, wherein the oxygen volume concentration under the oxygen-containing conditions is preferably 38-45%.

[0022] In this invention, the target particle size of the grinding is preferably: the proportion of particles with a diameter of less than 35 micrometers is more than 65%.

[0023] In this invention, the magnetic separation preferably includes a first magnetic separation and a second magnetic separation performed sequentially; the magnetic field strength of the first magnetic separation is preferably 950~1250mT, more preferably 1000~1150mT; the magnetic field strength of the second magnetic separation is preferably 900~1100mT, more preferably 950~1000mT.

[0024] The present invention involves mixing the gold-rich powder, sodium cyanide solution, lime, and functional activated carbon (referred to as the first mixture) and extracting them under oxygen and alkaline conditions.

[0025] In this invention, the mass concentration of the sodium cyanide solution is preferably 0.05~0.1wt%, more preferably 0.08wt%; the pH value of the sodium cyanide solution is preferably 9.5~10.5.

[0026] In this invention, the preparation method of the functional activated carbon preferably includes the following steps: activating activated carbon by mixing it with an aqueous solution of potassium hydroxide to obtain modified activated carbon; and heat-treating the modified activated carbon, potassium oxalate, and epichlorohydrin to obtain the functional activated carbon.

[0027] In this invention, the concentration of the potassium hydroxide aqueous solution is preferably 2-4 mol / L, more preferably 3 mol / L.

[0028] In this invention, the mass ratio of activated carbon to potassium hydroxide aqueous solution is preferably 1:10~13, more preferably 1:11~12.

[0029] In this invention, the activation temperature is preferably 150-160 degrees Celsius, more preferably 155 degrees Celsius, and the holding time is preferably 1-3 hours, more preferably 2 hours.

[0030] In this invention, the activation process preferably further includes washing and drying the resulting product sequentially; the washing is preferably water washing; the drying temperature is preferably 40-50 degrees Celsius, more preferably 45 degrees Celsius, and the heat preservation time is preferably 30-60 minutes, more preferably 45-50 minutes.

[0031] In this invention, the mass ratio of the modified activated carbon to potassium oxalate is preferably 1:0.3~0.5, more preferably 1:0.4.

[0032] In this invention, the mass ratio of the modified activated carbon to epichlorohydrin is preferably 1:0.8~1.2, more preferably 1:1.

[0033] In this invention, the heat treatment temperature is preferably 600-700 degrees Celsius, more preferably 650 degrees Celsius, and the heat treatment time is preferably 3-5 hours, more preferably 4 hours.

[0034] In this invention, the first mixing preferably includes the following steps: mixing lime and gold-rich powder to form a pile, then spraying sodium cyanide solution into the gold-rich mineral pile for heap leaching, then separating the solid and liquid phases to collect the liquid phase, and then mixing the liquid phase with functional activated carbon for adsorption.

[0035] In this invention, the amount of lime and gold-rich powder added is based on the pH value of the gold-rich mineral pile, preferably 9.5 to 10.5, more preferably 10.

[0036] In this invention, the height of the gold-rich mineral pile is preferably 3-5m, the width is preferably 3-5m, and the length is preferably 10-12m.

[0037] In this invention, the spray intensity is preferably 18~22 L / (h·m). 2 ), more preferably 20 L / (h·m 2 The preferred time is 90 to 100 days, and more preferably 95 days.

[0038] In this invention, during the spraying process, it is preferable to fill the sodium cyanide solution with oxygen-enriched gas; the oxygen purity of the oxygen-enriched gas is preferably 60-70%, and the filling pressure is preferably 35-50 kPa.

[0039] In this invention, the solid-liquid separation is preferably performed by filtration.

[0040] In this invention, the mass ratio of the liquid phase to the functional activated carbon is preferably 1000:0.5~1.2, and more preferably 1000:1.

[0041] In this invention, the adsorption time is preferably 6 to 12 hours, more preferably 8 to 9 hours.

[0042] In this invention, the adsorption process preferably further includes solid-liquid separation of the resulting product; the solid-liquid separation is preferably filtration.

[0043] The present invention involves mixing the gold-poor powder, sodium cyanide solution, lime, and activated carbon (referred to as the second mixture) and extracting them under oxygen and alkaline conditions.

[0044] In this invention, the mass concentration of the sodium cyanide solution is preferably 0.05~0.1wt%, more preferably 0.08wt%; the pH value of the sodium cyanide solution is preferably 9.5~10.5.

[0045] In this invention, the second mixing preferably includes the following steps: mixing lime and gold-poor powder to form a pile, then spraying sodium cyanide solution into the gold-poor mineral pile for heap leaching, followed by solid-liquid separation to collect the liquid phase, and then mixing the liquid phase with activated carbon for adsorption.

[0046] In this invention, the amount of lime and gold-poor powder added is based on the pH value of the gold-poor mineral pile, preferably 9.5 to 10.5, more preferably 10.

[0047] In this invention, the height of the gold-poor mineral pile is preferably 4-5m, the width is preferably 4-5m, and the length is preferably 15-18m.

[0048] In this invention, the spray intensity is preferably 20~22 L / (h·m). 2 ), more preferably 21 L / (h·m 2 The preferred time is 80-90 days, and more preferably 85 days.

[0049] In this invention, during the spraying process, it is preferable to fill the sodium cyanide solution with oxygen-enriched gas; the oxygen purity of the oxygen-enriched gas is preferably 60-70%, and the filling pressure is preferably 35-50 kPa.

[0050] In this invention, the solid-liquid separation is preferably performed by filtration.

[0051] In this invention, the mass ratio of the liquid phase to activated carbon is preferably 1000:0.3~0.8, more preferably 1000:0.5.

[0052] In this invention, the adsorption time is preferably 8 to 12 hours, more preferably 10 hours.

[0053] In this invention, the adsorption process preferably further includes solid-liquid separation of the resulting product; the solid-liquid separation is preferably filtration.

[0054] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments.

[0055] In a specific embodiment of the present invention, the preparation method of the functional activated carbon is as follows: Activated carbon and potassium hydroxide aqueous solution (concentration 3 mol / L) are mixed at a mass ratio of 1:12, activated at 155°C for 2 hours, washed with water, and dried at 45°C for 50 minutes to obtain modified activated carbon. Modified activated carbon is then mixed with potassium oxalate at a mass ratio of 1:0.4 and epichlorohydrin at a mass ratio of 1:1, and kept at 650°C for 4 hours to obtain functional activated carbon.

[0056] Example 1: This embodiment provides a method for extracting gold from low-grade gold ore by wetting, and the specific steps are as follows: (1) The low-grade gold ore was crushed to 1-5 mm and set aside. Then, it was initially roasted under oxygen-enriched conditions with an oxygen volume concentration of 51% and held at 450°C for 35 minutes; subsequently, it was roasted again under oxygen-containing conditions with an oxygen volume concentration of 23% and held at 620°C for 35 minutes; finally, it was roasted at high temperature under oxygen-containing conditions with an oxygen volume concentration of 42% and held at 790°C for 70 minutes. The roasted product was ground until the proportion of particles smaller than 35 micrometers was 68%. Then, it was initially magnetically separated under a magnetic field strength of 1050 mT, and then secondarily magnetically separated under a magnetic field strength of 970 mT to obtain gold-rich powder and gold-poor powder.

[0057] (2) Lime and gold-rich powder were mixed and piled up to obtain a gold-rich mineral pile with a pH of 10, 4m high, 4m wide, and 12m long. A sodium cyanide solution (0.07wt% concentration, pH 10) was filled with oxygen-enriched gas with an oxygen purity of 65% at a pressure of 45kPa. The resulting sodium cyanide solution was then sprayed into the gold-rich mineral pile at an intensity of 20L / (h·m). 2 The mixture was heap-leached for 95 days, filtered, and the liquid phase was collected. The liquid phase and functional activated carbon were then mixed and adsorbed for 9 hours at a mass ratio of 1000:1. After filtration, functional activated carbon for adsorbing gold was obtained.

[0058] (3) The lime and the obtained gold-poor powder were mixed and piled up to obtain a gold-poor mineral pile with a pH value of 10.5. The height of the gold-poor mineral pile was 5m, the width was 5m, and the length was 15m. An oxygen-enriched gas with an oxygen purity of 65% was introduced into the sodium cyanide solution at a pressure of 45kPa. Then, a sodium cyanide solution (mass concentration of 0.08wt%, pH value of 10.5) was sprayed into the gold-poor mineral pile for heap leaching for 85 days at a spraying intensity of 21L / (h·m). 2 The liquid phase was filtered and collected. Then, the liquid phase and activated carbon were mixed at a mass ratio of 1000:0.6 and adsorbed for 10 hours. After filtration, activated carbon adsorbing gold was obtained.

[0059] Example 2: This embodiment provides a method for extracting gold from low-grade gold ore by wetting, and the specific steps are as follows: (1) The low-grade gold ore was crushed to 1-5 mm and set aside. Then, it was initially roasted under oxygen-enriched conditions with an oxygen volume concentration of 51% and held at 400°C for 50 minutes; subsequently, it was roasted again under oxygen-containing conditions with an oxygen volume concentration of 22% and held at 630°C for 40 minutes; finally, it was roasted at high temperature under oxygen-containing conditions with an oxygen volume concentration of 42% and held at 780°C for 65 minutes. The roasted product was then ground until the proportion of particles smaller than 35 micrometers was 74%. Afterwards, it underwent preliminary magnetic separation under a magnetic field strength of 1150 mT, followed by secondary magnetic separation under a magnetic field strength of 950 mT to obtain gold-rich powder and gold-poor powder.

[0060] (2) Lime and gold-rich powder were mixed and piled up to obtain a gold-rich mineral pile with a pH of 10, 4m high, 4m wide, and 12m long. A sodium cyanide solution (0.07wt% concentration, pH 10) was filled with oxygen-enriched gas with an oxygen purity of 65% at a pressure of 45kPa. The resulting sodium cyanide solution was then sprayed into the gold-rich mineral pile at an intensity of 20L / (h·m). 2 The mixture was heap-leached for 95 days, filtered, and the liquid phase was collected. The liquid phase and functional activated carbon were then mixed and adsorbed for 9 hours at a mass ratio of 1000:1. After filtration, functional activated carbon for adsorbing gold was obtained.

[0061] (3) The lime and the obtained gold-poor powder were mixed and piled up to obtain a gold-poor mineral pile with a pH value of 10.5. The height of the gold-poor mineral pile was 5m, the width was 5m, and the length was 15m. An oxygen-enriched gas with an oxygen purity of 65% was introduced into the sodium cyanide solution at a pressure of 45kPa. Then, a sodium cyanide solution (mass concentration of 0.08wt%, pH value of 10.5) was sprayed into the gold-poor mineral pile for heap leaching for 85 days at a spraying intensity of 21L / (h·m).2 The liquid phase was filtered and collected. Then, the liquid phase and activated carbon were mixed at a mass ratio of 1000:0.7 and adsorbed for 10 hours. After filtration, activated carbon adsorbing gold was obtained.

[0062] Example 3: This embodiment provides a method for extracting gold from low-grade gold ore by wetting, and the specific steps are as follows: (1) The low-grade gold ore was crushed to 1-5 mm and set aside. Then, it was initially roasted under oxygen-enriched conditions with an oxygen volume concentration of 51% and held at 550°C for 35 minutes; subsequently, it was roasted again under oxygen-containing conditions with an oxygen volume concentration of 23% and held at 640°C for 45 minutes; finally, it was roasted at high temperature under oxygen-containing conditions with an oxygen volume concentration of 42% and held at 760°C for 60 minutes. The roasted product was ground until the proportion of particles smaller than 35 micrometers was 75%. Then, it was initially magnetically separated under a magnetic field strength of 1200 mT, and then secondarily magnetically separated under a magnetic field strength of 900 mT to obtain gold-rich powder and gold-poor powder.

[0063] (2) Lime and gold-rich powder were mixed and piled up to obtain a gold-rich mineral pile with a pH of 10, 4m high, 4m wide, and 12m long. A sodium cyanide solution (0.07wt% concentration, pH 10) was filled with oxygen-enriched gas with an oxygen purity of 65% at a pressure of 45kPa. The resulting sodium cyanide solution was then sprayed into the gold-rich mineral pile at an intensity of 20L / (h·m). 2 The mixture was heap-leached for 95 days, filtered, and the liquid phase was collected. The liquid phase and functional activated carbon were then mixed and adsorbed for 9 hours at a mass ratio of 1000:1. After filtration, functional activated carbon for adsorbing gold was obtained.

[0064] (3) The lime and the obtained gold-poor powder were mixed and piled up to obtain a gold-poor mineral pile with a pH value of 10.5. The height of the gold-poor mineral pile was 5m, the width was 5m, and the length was 15m. An oxygen-enriched gas with an oxygen purity of 65% was introduced into the sodium cyanide solution at a pressure of 45kPa. Then, a sodium cyanide solution (mass concentration of 0.08wt%, pH value of 10.5) was sprayed into the gold-poor mineral pile for heap leaching for 85 days at a spraying intensity of 21L / (h·m). 2 The liquid phase was filtered and collected. Then, the liquid phase and activated carbon were mixed at a mass ratio of 1000:0.6 and adsorbed for 10 hours. After filtration, activated carbon adsorbing gold was obtained.

[0065] Example 4: This embodiment provides a method for extracting gold from low-grade gold ore by wetting, and the specific steps are as follows: (1) The low-grade gold ore was crushed to 1-5 mm and set aside. Then, it was initially roasted under oxygen-enriched conditions with an oxygen volume concentration of 51% and held at 500°C for 45 minutes; subsequently, it was roasted a second time under oxygen-containing conditions with an oxygen volume concentration of 23% and held at 645°C for 35 minutes; finally, it was roasted at high temperature under oxygen-containing conditions with an oxygen volume concentration of 40% and held at 770°C for 70 minutes. The roasted product was ground until the proportion of particles smaller than 35 micrometers was 69%. Then, it was initially magnetically separated under a magnetic field strength of 1100 mT, and then a second time under a magnetic field strength of 1000 mT to obtain gold-rich powder and gold-poor powder.

[0066] (2) Lime and gold-rich powder were mixed and piled up to obtain a gold-rich mineral pile with a pH of 10, 4m high, 4m wide, and 12m long. A sodium cyanide solution (0.07wt% concentration, pH 10) was filled with oxygen-enriched gas with an oxygen purity of 65% at a pressure of 45kPa. The resulting sodium cyanide solution was then sprayed into the gold-rich mineral pile at an intensity of 20L / (h·m). 2 The mixture was heap-leached for 95 days, filtered, and the liquid phase was collected. The liquid phase and functional activated carbon were then mixed and adsorbed for 9 hours at a mass ratio of 1000:1. After filtration, functional activated carbon for adsorbing gold was obtained.

[0067] (3) The lime and the obtained gold-poor powder were mixed and piled up to obtain a gold-poor mineral pile with a pH value of 10.5. The height of the gold-poor mineral pile was 5m, the width was 5m, and the length was 15m. An oxygen-enriched gas with an oxygen purity of 65% was introduced into the sodium cyanide solution at a pressure of 45kPa. Then, a sodium cyanide solution (mass concentration of 0.08wt%, pH value of 10.5) was sprayed into the gold-poor mineral pile for heap leaching for 85 days at a spraying intensity of 21L / (h·m). 2 The liquid phase was filtered and collected. Then, the liquid phase and activated carbon were mixed at a mass ratio of 1000:0.5 and adsorbed for 10 hours. After filtration, activated carbon adsorbing gold was obtained.

[0068] Comparative Example 1: The preparation method of this comparative example is the same as that of Example 1, except that a second calcination was not performed.

[0069] Comparative Example 2: The preparation method of this comparative example is the same as that of Example 1, except that the first magnetic separation was not performed.

[0070] Comparative Example 3: The preparation method of this comparative example is the same as that of Example 1, except that the functional activated carbon is replaced with an equal mass of activated carbon.

[0071] Comparative Example 4: The preparation method of this comparative example is the same as that of Example 1, except that in step (2), the mass ratio of liquid phase to functional activated carbon is 1000:0.1.

[0072] Test Example 1: Recovery rates were tested for Examples 1-4 and Comparative Examples 1-4. The functional activated carbon adsorbing gold and the activated carbon adsorbing gold were sieved, desorbed, and smelted to obtain gold. The gold was weighed, the recovery rate was calculated, and the purity was tested. The test results are shown in Table 1 and... Figure 1 As shown.

[0073] Table 1 Recovery rates of Examples 1-4 and Comparative Examples 1-4:

[0074] According to Table 1 and Figure 1 As can be seen, the method for extracting gold from low-grade gold ore by leaching provided by this invention can extract gold from low-grade gold ore with a high recovery rate and the final product has high purity, making the application of gold more convenient, the post-processing simple, the economic benefits significant, and it has broad application prospects.

[0075] The embodiments of the present invention have been described above; however, these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the above embodiments of the present invention without inventive effort are within the protection scope of the present invention.

Claims

1. A method for extracting gold from low-grade gold ore by leaching, characterized in that, Includes the following steps: (1) The low-grade gold ore is crushed, roasted, ground and magnetically separated in sequence to obtain gold-rich powder and gold-poor powder; (2) The gold-rich powder, sodium cyanide solution, lime and functional activated carbon are mixed and extracted under oxygen and alkaline conditions; (3) The gold powder, sodium cyanide solution, lime and activated carbon are mixed and extracted under oxygen and alkaline conditions.

2. The method according to claim 1, characterized in that, The roasting includes a first roasting, a second roasting, and a third roasting performed sequentially. The temperature of the first roasting is 400~550 degrees Celsius, and the holding time is 30~50 minutes; The first calcination is carried out under oxygen-enriched conditions, wherein the oxygen volume concentration under these conditions is 50-52%. The second roasting temperature is 600~650 degrees Celsius, and the holding time is 30~50 minutes; The second calcination is carried out under oxygen-containing conditions, wherein the oxygen volume concentration of the oxygen-containing conditions is 20-25%; The third roasting temperature is 750-800 degrees Celsius, and the holding time is 50-80 minutes; The third calcination is carried out under oxygen-containing conditions, wherein the oxygen volume concentration of the oxygen-containing conditions is 38-45%.

3. The method according to claim 1, characterized in that, The target particle size for grinding is: the proportion of particles with a diameter of less than 35 micrometers is more than 65%.

4. The method according to claim 1, characterized in that, The magnetic separation includes a first magnetic separation and a second magnetic separation performed sequentially; the magnetic field strength of the first magnetic separation is 950~1250mT; the magnetic field strength of the second magnetic separation is 900~1100mT.

5. The method according to claim 1, characterized in that, The preparation method of the functional activated carbon includes the following steps: activating activated carbon by mixing it with an aqueous solution of potassium hydroxide to obtain modified activated carbon; and heat-treating the modified activated carbon, potassium oxalate, and epichlorohydrin to obtain the functional activated carbon.

6. The method according to claim 5, characterized in that, The activation temperature is 150-160 degrees Celsius, and the holding time is 1-3 hours.

7. The method according to claim 5, characterized in that, The mass ratio of the modified activated carbon to potassium oxalate is 1:0.3~0.5; the mass ratio of the modified activated carbon to epichlorohydrin is 1:0.8~1.

2.

8. The method according to claim 5, characterized in that, The heat treatment temperature is 600~700 degrees Celsius, and the holding time is 3~5 hours.

9. The method according to claim 1, characterized in that, In step (2), the mixing includes the following steps: mixing lime and gold-rich powder to form a pile, then spraying sodium cyanide solution into the gold-rich mineral pile for heap leaching, then separating the solid and liquid phases to collect the liquid phase, and then mixing the liquid phase with functional activated carbon for adsorption.

10. The method according to claim 1, characterized in that, In step (3), the mixing includes the following steps: mixing lime and gold-poor powder to form a pile, then spraying sodium cyanide solution into the gold-poor mineral pile for heap leaching, then separating the solid and liquid phases to collect the liquid phase, and then mixing the liquid phase with activated carbon for adsorption.

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