A method and apparatus for segmented and precise control of enhanced separation of carbon- and arsenic-containing fine-grained gold ores

Abstract

This invention provides a method and apparatus for segmented and precisely controlled enhanced separation of carbon- and arsenic-containing fine-grained gold ore, belonging to the field of mineral processing technology. The apparatus includes a feeding system, a heating system, a suspension roasting furnace, a gas supply system, a detection system, and a grinding and leaching system. The method involves: first, crushing and grinding the carbon- and arsenic-containing fine-grained gold ore, then drying it; next, conveying the ore powder to the pre-oxidation chamber of the suspension roasting furnace for pre-oxidation and arsenic removal roasting in a suspended state; then feeding it into the oxidation chamber of the suspension roasting furnace for decarburization roasting in a suspended state; after the decarburized roasted ore has naturally cooled, adding water for grinding, and cyaniding the slurry to obtain a gold-bearing precious liquor. This invention can precisely control the desulfurization and decarburization of carbon- and arsenic-containing fine-grained gold ore under suitable conditions, achieving high mass and heat transfer efficiency, high arsenic and carbon impurity removal rates, low energy consumption and cost per unit processing volume, easily controllable and stable product properties, and easy scaling up of equipment.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a method and apparatus for enhanced separation of carbon- and arsenic-containing fine-grained gold ore with segmented and precise control. Background Technology

[0002] As easily processed, high-grade gold resources are gradually depleted, the proportion of difficult-to-process gold ores with complex structures, low grades, fine-grained intercalation, high content of impurity metal elements, high arsenic, high sulfur, and organic carbon content is gradually increasing, and they have become the main raw materials for gold production.

[0003] Patent CN1932052A discloses an integrated kiln-type oxidative roasting process for gold extraction from refractory gold ores. It proposes that the roasting and cyanide extraction processes of refractory gold ores are completed within the same tunnel kiln, offering advantages such as low investment, simple equipment, and a short process flow. However, this method involves static roasting and requires the addition of carbon powder, coke powder, or coal powder as combustion aids, which easily leads to sintering and affects the leaching effect.

[0004] Patent CN104498705A discloses a pretreatment method for complex and difficult-to-process gold ore. This method has the advantages of high removal rates of sulfur, arsenic and carbon, high recovery rate of valuable metals, low cost and simple operation. However, the product quality is uneven and the roasting temperature needs to be controlled by a fuel gun and an emergency water spray cooling device set in the roasting furnace. The process is complicated.

[0005] Patent CN118497512A discloses a method for biological oxidation-suspension roasting-cyanide leaching of refractory gold ore. This method uses dual pretreatment of biological oxidation and suspension roasting plus mechanical activation to effectively shorten the leaching cycle and improve the gold leaching rate. However, the process is complex and the energy consumption per unit of processing is high.

[0006] In refractory gold ores containing carbonaceous and arsenic particles, gold is finely embedded and often closely associated with sulfide, carbonate, and silicate minerals, resulting in low gold leaching rates from direct leaching. Physical or chemical methods are commonly used to break the gold encapsulation by gangue minerals in the ore, enhancing the interaction between subsequent leaching agents and gold, while simultaneously reducing the influence of carbonaceous, sulfide, and carbonate minerals in the ore on the leaching process to improve the gold leaching rate.

[0007] The ore targeted by this invention contains elements such as arsenic, sulfur, and carbon, and is a typical refractory gold ore. Pretreatment can effectively open the mineral's encapsulation of gold and weaken the negative effects of harmful elements, which is an effective way to achieve efficient utilization of refractory gold ore. Summary of the Invention

[0008] To address the problems existing in current recalcitrant gold ore beneficiation technologies containing carbon and arsenic fine particles, this invention provides a device and method for enhanced beneficiation of carbon and arsenic fine-particle gold ore through segmented and precise control. This invention can precisely control the desulfurization and decarbonization of carbon and arsenic fine-particle gold ore under suitable conditions, achieving high mass and heat transfer efficiency, high removal rate of arsenic and carbon impurities, low energy consumption and cost per unit processing volume, easily controllable and stable product properties, and easy scaling up of equipment.

[0009] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0010] (1) The carbon- and arsenic-containing fine-grained gold ore is crushed and ground, and after drying, powder ore with a particle size of -0.074 mm accounting for 80%~90% of the total mass is obtained and placed in the feed hopper;

[0011] (2) Fill the oxidation chamber of the suspension roaster to a certain height to prevent the material from escaping from the inlet. Start the heating system, gas supply system, feeding system and detection system. Under the action of gas, the ore powder passes through the pre-oxidation loosening chamber and pre-oxidation fluidization chamber of the suspension roaster in a suspended state for oxidation and arsenic removal, to obtain oxidized and arsenic-removed roasted sand. Detect the SO2 generated during the oxidation and arsenic removal process using a flue gas analyzer, and adjust the gas flow and heating temperature of the corresponding pre-oxidation loosening chamber and pre-oxidation fluidization chamber to ensure that As in the ore powder is converted into gaseous compounds. The reaction formula on which the complete reaction is based is:

[0012] As2(g)+O2(g)=AsO(g) (1);

[0013] FeAsS+2.5FeS2+O2=3.5FeS+0.5As2S3(g)+SO2(g) (2);

[0014] FeAsS+2FeS2+O2=3FeS+0.25As4S4(g)+SO2(g) (3);

[0015] FeAsS+2.5O2(g)=0.5Fe2O3+0.5As2O3(g)+SO2(g) (4);

[0016] (3) The arsenic-removed roasted sand is introduced into the oxidation loosening chamber and oxidation fluidization chamber of the suspension roasting furnace in a suspended state under the action of gas for oxidation decarburization, to obtain arsenic-removed and decarburized roasted sand; the CO2 generated during the oxidation decarburization process is detected by a flue gas analyzer, and the gas flow and heating temperature of the corresponding oxidation loosening chamber and oxidation fluidization chamber are adjusted to ensure that the C in the ore powder is completely converted into CO2. The reaction formula on which the complete reaction is based is:

[0017] CO2(g) + C = 2CO(g) (5;

[0018] 2C + O2(g) = 2CO (6);

[0019] C + O₂(g) = CO₂(g) (7;

[0020] 2CO + O2(g) = 2CO2(g) (8;

[0021] (4) The arsenic- and decarbonized roasted sand enters the hopper under the action of gravity to obtain pretreated gold ore products;

[0022] (5) The pretreated gold ore products are fed into the grinding and leaching system for grinding-cyanide leaching. After leaching, the material is filtered to obtain gold-containing precious solution.

[0023] In the above method, the Au content in the carbon- and arsenic-containing fine-grained gold ore is 2.8 g / t to 6.4 g / t, the mass percentage of C is 3% to 10%, and the mass percentage of As is 0.2% to 0.8%.

[0024] In the above method, the heating temperature in step (2) is 500℃~600℃, the heating time is 10min~20min, the gas introduced is air, and the gas volume is 3m³. 3 / h~5m 3 / h.

[0025] In the above method, the heating temperature in step (3) is 600℃~750℃, the heating time is 25min~50min, the gas introduced is oxygen, and the gas volume is 8m³. 3 / h~12m 3 / h.

[0026] In the above method, the C content in the pretreated gold ore product is <0.8%, and the As removal rate is >85%.

[0027] In the above method, the grinding concentration in step (5) is 40%~65%, the grinding fineness is -0.074mm>85%, the amount of sodium cyanide is 0.8kg / t~10kg / t, the cyanide leaching time is 20h~30h, and the leaching rate of Au in the precious metal solution is >90%.

[0028] The above method employs a segmented and precisely controlled device for enhanced separation of carbon- and arsenic-containing fine-grained gold ore, comprising a feeding system, a heating system, a suspension roasting furnace, a gas supply system, a detection system, and a grinding and leaching system, wherein the feeding system, the suspension roasting furnace, and the grinding and leaching system are connected in sequence.

[0029] Furthermore, the interior of the suspension roasting furnace is equipped with an air distribution plate, with an oxidation chamber at the upper end and a gas chamber at the lower end. The oxidation chamber is divided into four independent reaction chambers by three baffles, allowing the gas to flow vertically and horizontally guided by the baffles. From right to left, these chambers are: a pre-oxidation loosening chamber, a pre-oxidation fluidization chamber, an oxidation loosening chamber, and an oxidation fluidization chamber. The gas chamber is divided into four independent gas chambers by three baffles, corresponding to the positions of the four independent reaction chambers.

[0030] Furthermore, the feeding system includes a feeding bin and a screw feeder, the outlet of the feeding bin is connected to the inlet of the screw feeder, and the outlet of the screw feeder is connected to the upper end of the oxidation chamber in the suspension roasting furnace.

[0031] The heating system includes a heater and a temperature control cabinet. The heating system is located on the outer wall of the suspension roasting furnace, and the heating temperature is precisely controlled by the temperature control cabinet.

[0032] The gas supply system includes a gas tank, a gas flow meter, and an air distribution plate; the outlet of the gas tank and the lower end of the gas chamber in the suspension roasting furnace are connected through the gas flow meter.

[0033] The detection system includes a gas collector, a flue gas analyzer, and a computer. The gas collector is connected to the flue gas analyzer, and the computer is assembled with the flue gas analyzer.

[0034] The grinding and leaching system includes a mill and a leaching tank. The inlet of the mill is connected to the outlet of the suspension roasting furnace, and the outlet of the mill is connected to the inlet of the leaching tank.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] This invention transforms mineral powder from a stockpiled state to a loose state in a pre-oxidation and loosening chamber. Under the atmosphere of 500℃~600℃ in the pre-oxidation chamber, As in the powder is converted into gaseous compounds. The SO2 content is detected by a flue gas analyzer to determine whether the As in the powder has been completely removed. The roasted sand after arsenic removal enters the oxidation chamber and undergoes decarburization under an oxidizing atmosphere of 600℃~750℃. At this time, the carbon in the powder is converted into CO2. The CO2 content is detected by a flue gas analyzer to determine whether the carbon in the powder has been completely removed. Ultimately, precise control of arsenic and carbon removal is achieved. At the same time, the removal of arsenic and carbon will form pores or cracks, reducing grinding energy consumption and facilitating gold leaching, thereby achieving the purpose of enhanced separation.

[0037] This invention can precisely control the desulfurization and decarbonization of fine-grained gold ore containing carbon and arsenic under suitable conditions, with high mass and heat transfer efficiency, high removal rate of arsenic and carbon impurities, low energy consumption and cost per unit processing volume, easy control and stability of product properties, and easy realization of large-scale equipment. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a device for segmented and precise control of enhanced separation of carbon- and arsenic-containing fine-grained gold ore, as described in this invention.

[0039] Figure 2 This is a diagram of the suspension roasting furnace in the device for segmented and precisely controlled enhanced separation of carbon- and arsenic-containing fine-grained gold ore according to the present invention.

[0040] In the diagram, 11 is the feed hopper; 12 is the screw feeder; 21 is the temperature control cabinet; 22 is the heater; 31 is the gas tank; 32 is the gas flow meter; 33 is the air distribution plate; 4 is the suspension roasting furnace; 41 is the pre-oxidation loosening chamber; 42 is the pre-oxidation fluidized chamber; 43 is the oxidation loosening chamber; 44 is the oxidation fluidized chamber; 45 is the gas chamber; 51 is the gas collector; 52 is the flue gas analyzer; 53 is the computer; 61 is the mill; and 62 is the leaching tank. Detailed Implementation

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

[0042] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0043] (1) In this embodiment, the Au content in the carbon-containing and arsenic-containing fine-grained gold ore is 2.8 g / t to 6.4 g / t, the mass percentage of C is 3% to 10%, and the mass percentage of As is 0.2% to 0.8%. The carbon-containing and arsenic-containing fine-grained gold ore is crushed and ground, and after drying, powder with a particle size of -0.074 mm accounting for 80% to 90% of the total mass is obtained and placed in the feed hopper 11.

[0044] (2) Fill the oxidation chamber of the suspension roasting furnace 4 with a certain height of material to prevent the material from escaping from the inlet. Start the heating system, gas supply system, feeding system and detection system. Under the action of gas, the powdered ore passes through the pre-oxidation loosening chamber 41 and pre-oxidation fluidization chamber 42 of the suspension roasting furnace 4 in a suspended state for oxidation and arsenic removal to obtain oxidized and arsenic-removed roasted sand. Detect the SO2 generated during the oxidation and arsenic removal process using a flue gas analyzer, and adjust the gas flow and heating temperature of the corresponding pre-oxidation loosening chamber 41 and pre-oxidation fluidization chamber 42. The heating temperature is 500℃~600℃, the heating time is 10min~20min, the gas introduced is air, and the gas flow is 3m³. 3 / h~5m 3 / h; To ensure that As in the fine ore is converted into gaseous compounds, the reaction formula on which the complete reaction is based is:

[0045] As2(g)+O2(g)=AsO(g) (1);

[0046] FeAsS+2.5FeS2+O2=3.5FeS+0.5As2S3(g)+SO2(g) (2);

[0047] FeAsS+2FeS2+O2=3FeS+0.25As4S4(g)+SO2(g) (3);

[0048] FeAsS+2.5O2(g)=0.5Fe2O3+0.5As2O3(g)+SO2(g) (4);

[0049] (3) The calcined sand after oxidative dearsenic removal is introduced into the oxidation loosening chamber 43 and oxidation fluidization chamber 44 of the suspension roasting furnace 4 in a suspended state under the action of gas for oxidative decarburization, to obtain calcined sand after arsenic removal and decarburization; the CO2 generated during the oxidation decarburization process is detected by the flue gas analyzer 52, and the gas flow rate and heating temperature of the corresponding oxidation loosening chamber 43 and oxidation fluidization chamber 44 are adjusted accordingly. The heating temperature is 600℃~750℃, the heating time is 25min~50min, the introduced gas is oxygen, and the gas flow rate is 8m³. 3 / h~12m 3 / h; Ensure that the C in the ore powder is completely converted into CO2. The reaction formula on which the complete reaction is based is:

[0050] CO2(g) + C = 2CO(g) (5;

[0051] 2C + O2(g) = 2CO (6);

[0052] C + O₂(g) = CO₂(g) (7;

[0053] 2CO + O2(g) = 2CO2(g) (8;

[0054] (4) The arsenic- and decarbonized roasted sand enters the hopper under gravity to obtain pretreated gold ore products; the C content in the pretreated gold ore products is <0.8%, and the As removal rate is >85%;

[0055] (5) The pretreated gold ore products are fed into the grinding and leaching system for grinding-cyanide leaching. The grinding concentration is 40%~65%, the grinding fineness is -0.074mm>85%, the sodium cyanide dosage is 0.8kg / t~10kg / t, and the cyanide leaching time is 20h~30h. After the leaching is completed, the material is filtered to obtain gold-containing precious solution. The leaching rate of Au in the gold-containing precious solution is >90%.

[0056] The above method employs a segmented, precisely controlled device for enhanced separation of fine-grained carbonaceous and arsenic-containing gold ores, such as... Figure 1 As shown, it includes a feeding system, a heating system, a suspension roasting furnace, a gas supply system, a detection system, and a grinding and leaching system, which are connected in sequence.

[0057] like Figure 2 As shown, the interior of the suspension roasting furnace 4 is equipped with an air distribution plate 33. The upper end of the air distribution plate 33 is an oxidation chamber, and the lower end is a gas chamber 45. The oxidation chamber is divided into four independent reaction chambers by three baffles, so that the gas is guided by the baffles to flow up and down. From right to left, they are: pre-oxidation loosening chamber 41, pre-oxidation fluidization chamber 42, oxidation loosening chamber 43, and oxidation fluidization chamber 44. The gas chamber 45 is divided into four independent gas chambers by three baffles, which correspond to the positions of the four independent reaction chambers.

[0058] The feeding system includes a feeding bin 11 and a screw feeder 12. The outlet of the feeding bin 11 is connected to the inlet of the screw feeder 12. The outlet of the screw feeder 12 is connected to the upper end of the oxidation chamber in the suspension roasting furnace 4.

[0059] The heating system includes a heater 22 and a temperature control cabinet 21. The heating system is located on the outer wall of the suspension roasting furnace 4, and the heating temperature is precisely controlled by the temperature control cabinet 21.

[0060] The gas supply system includes a gas tank 31, a gas flow meter 32, and an air distribution plate 33; the outlet of the gas tank 31 and the lower end of the gas chamber in the suspension roasting furnace 4 are connected through the gas flow meter 32.

[0061] The detection system includes a gas collector 51, a flue gas analyzer 52, and a computer 53. The gas collector 51 is connected to the flue gas analyzer 52, and the computer 53 is assembled with the flue gas analyzer 52.

[0062] The grinding and leaching system includes a mill 61 and a leaching tank 62. The inlet of the mill 61 is connected to the outlet of the suspension roasting furnace 4, and the outlet of the mill 61 is connected to the inlet of the leaching tank 62.

[0063] Example 1

[0064] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0065] (1) A certain carbon- and arsenic-containing fine-grained gold ore has an Au content of 3.49 g / t, and an As and C content of 0.35% and 4.77%, respectively. The ore is crushed to a particle size of -2 mm, then ground to -0.074 mm, accounting for 80% of the total mass, and dried to obtain powder ore.

[0066] (2) The powdered ore is fed into the feeding hopper 11, which is equipped with a screw feeder 12 at the bottom. The material is filled to a certain height in the oxidation chamber. The heating system, gas supply system, feeding system and detection system are started. The powdered ore passes through the pre-oxidation chamber of the suspension roasting furnace 4 in a suspended state under the action of gas. It is heated to 600°C for oxidation and arsenic removal to obtain oxidized and arsenic-removed roasted sand. The air volume is 4m³. 3 / h, S and As in the ore powder are converted into SO2 and As gaseous compounds, and the residence time of the ore powder in the pre-oxidation chamber is 15min;

[0067] (3) The arsenic-removed calcined sand is introduced into the oxidation chamber of the suspension roasting furnace 4 in a suspended state, and roasted at a temperature of 700°C and an oxygen flow rate of 10 m³ / s. 3 Oxidation and decarburization were carried out under an atmosphere of / h to obtain arsenic-decarburized roasted sand; C in the fine ore was completely converted into CO2 after oxidation, and the residence time of the pre-oxidized arsenic-decarburized roasted sand in the oxidation chamber was 40min.

[0068] (4) The arsenic- and decarbonized roasted sand enters the hopper and is cooled to room temperature to obtain pretreated gold ore product with a C content of 0.62% and an As removal rate of 88.62%;

[0069] (5) The pretreated concentrate was mixed with water to make a slurry with a mass concentration of 40%, and ground to -0.074 mm, accounting for 90% of the total mass. Sodium cyanide was added for leaching, with a sodium cyanide dosage of 5 kg / t and a cyanide leaching time of 24 h. The leached material was filtered to obtain a gold-containing solution, with a gold-containing solution leaching rate of 91.72%.

[0070] Example 2

[0071] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0072] (1) The Au content of the carbon-containing and arsenic-containing fine-grained ore is 4.15 g / t, and the As and C contents are 0.51% and 6.21%, respectively. The ore is ground to a particle size of -0.074 mm, accounting for 82% of the total mass, and then dried to obtain powder ore.

[0073] (2) The powdered ore is fed into the feeding hopper 11, which is equipped with a screw feeder 12 at the bottom. The material is filled to a certain height into the oxidation chamber. The heating system, gas supply system, feeding system and detection system are started. The powdered ore passes through the pre-oxidation chamber of the suspension roasting furnace 4 in a suspended state under the action of gas. It is heated to 580°C for oxidation and arsenic removal to obtain oxidized and arsenic-removed roasted sand. The air volume introduced is 4.5 m³. 3 / h, S and As in the ore powder are converted into SO2 and As gaseous compounds, and the residence time of the ore powder in the pre-oxidation chamber is 18min;

[0074] (3) The arsenic-removed calcined sand is introduced into the oxidation chamber of the suspension roasting furnace 4 in a suspended state, and roasted at a temperature of 720°C and an oxygen flow rate of 10 m³ / s. 3 Oxidation and decarburization were carried out under an atmosphere of / h to obtain arsenic-decarburized roasted sand; C in the fine ore was completely converted into CO2 after oxidation, and the residence time of the pre-oxidized arsenic-decarburized roasted sand in the oxidation chamber was 45min.

[0075] (4) The arsenic- and decarbonized roasted sand is fed into the hopper and cooled to room temperature to obtain pretreated gold ore product. The C content of the pretreated gold ore product is 0.42% and the As removal rate is 90.82%.

[0076] (5) The pretreated concentrate was mixed with water to make a slurry with a mass concentration of 50%, and ground to -0.074 mm, accounting for 92.46% of the total mass. Sodium cyanide was added for leaching, with a sodium cyanide dosage of 8 kg / t and a cyanide leaching time of 30 h. The leached material was filtered to obtain a gold-containing solution, with a gold-containing solution leaching rate of 96.28%.

[0077] Example 3

[0078] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0079] (1) A certain carbon- and arsenic-containing fine-grained gold ore has an Au content of 2.84 g / t, and an As and C content of 0.62% and 6.84%, respectively. The ore is crushed to a particle size of -2 mm, then ground to -0.074 mm, accounting for 80% of the total mass, and dried to obtain powder ore.

[0080] (2) The powdered ore is fed into the feeding hopper 11, which is equipped with a screw feeder 12 at the bottom. The material is filled to a certain height in the oxidation chamber. The heating system, gas supply system, feeding system and detection system are started. The powdered ore passes through the pre-oxidation chamber of the suspension roasting furnace 4 in a suspended state under the action of gas. It is heated to 600°C for oxidation and arsenic removal to obtain oxidized and arsenic-removed roasted sand. The air volume is 5m³. 3 / h, detect SO2 generated during the oxidative arsenic removal process, S and As in the ore powder are converted into SO2 and As gaseous compounds, and the residence time of the ore powder in the pre-oxidation chamber is 20min;

[0081] (3) The calcined sand that has been oxidized and dearsenicized is introduced into the oxidation chamber of the suspension roasting furnace in a suspended state, and roasted at a temperature of 750°C and an oxygen flow rate of 12m³. 3 Oxidation and decarburization were carried out under an atmosphere of / h to obtain arsenic-decarburized roasted sand; the residence time of the pre-oxidized arsenic-decarburized roasted sand in the oxidation chamber was 50min;

[0082] (4) The arsenic- and decarbonized roasted sand is fed into the hopper and cooled to room temperature to obtain pretreated gold ore product with a C content of 0.58% and an As removal rate of 91.12%;

[0083] (5) The pretreated concentrate was mixed with water to make a slurry with a mass concentration of 50%, and ground to -0.074 mm, accounting for 90% of the total mass. Sodium cyanide was added for leaching, with a sodium cyanide dosage of 8 kg / t and a cyanide leaching time of 24 h. The leached material was filtered to obtain a gold-containing solution, with a gold-containing solution leaching rate of 92.24%.

[0084] Example 4

[0085] A method for enhanced separation of fine-grained carbonaceous and arsenic-containing gold ore with segmented and precise control, using the same ore sample as in Example 3, is carried out according to the following steps:

[0086] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0087] (1) A certain carbon- and arsenic-containing fine-grained gold ore has an Au content of 2.84 g / t, and an As and C content of 0.62% and 6.84%, respectively. The ore is crushed to a particle size of -2 mm, then ground to -0.074 mm, accounting for 80% of the total mass, and dried to obtain powder ore.

[0088] (2) The powdered ore is fed into the feeding hopper 11, which is equipped with a screw feeder 12 at the bottom. The material is filled to a certain height in the oxidation chamber. The heating system, gas supply system, feeding system and detection system are started. The powdered ore passes through the pre-oxidation chamber of the suspension roasting furnace 4 in a suspended state under the action of gas. It is heated to 550°C for oxidation and arsenic removal to obtain oxidized and arsenic-removed roasted sand. The air volume is 4m³. 3 / h, detect SO2 generated during the oxidative arsenic removal process, S and As in the ore powder are converted into SO2 and As gaseous compounds, and the residence time of the ore powder in the pre-oxidation chamber is 15min;

[0089] (3) The calcined sand that has been oxidized and dearsenicized is introduced into the oxidation chamber of the suspension roasting furnace in a suspended state, and roasted at a temperature of 700°C and an oxygen flow rate of 10 m³ / s. 3 Oxidation and decarburization were carried out under an atmosphere of / h to obtain arsenic-decarburized roasted sand; the residence time of the pre-oxidized arsenic-decarburized roasted sand in the oxidation chamber was 40min;

[0090] (4) The arsenic- and decarbonized roasted sand is fed into the hopper and cooled to room temperature to obtain pretreated gold ore product with a C content of 0.64% and an As removal rate of 89.67%;

[0091] (5) The pretreated concentrate was mixed with water to make a slurry with a mass concentration of 50%, and ground to -0.074 mm, accounting for 92.46% of the total. Sodium cyanide was added for leaching, with a sodium cyanide dosage of 10 kg / t and a cyanide leaching time of 30 h. The leached material was filtered to obtain a gold-containing solution, with a gold-containing solution leaching rate of 92.04%.

[0092] Example 5

[0093] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0094] (1) A certain carbon- and arsenic-containing fine-grained gold ore has an Au content of 4.21 g / t, and an As and C content of 0.50% and 4.28%, respectively. The ore is crushed to a particle size of -2 mm, then ground to -0.074 mm, accounting for 85% of the total mass, and dried to obtain powder ore.

[0095] (2) The powdered ore is fed into the feeding hopper 11, which is equipped with a screw feeder 12 at the bottom. The material is filled to a certain height in the oxidation chamber. The heating system, gas supply system, feeding system and detection system are started. The powdered ore passes through the pre-oxidation chamber of the suspension roasting furnace 4 in a suspended state under the action of gas. It is heated to 500°C for oxidation and arsenic removal to obtain oxidized and arsenic-removed roasted sand. The air volume introduced is 3m³. 3 / h, detect SO2 generated during the oxidative arsenic removal process, S and As in the ore powder are converted into SO2 and As gaseous compounds, and the residence time of the ore powder in the pre-oxidation chamber is 10min;

[0096] (3) The arsenic-removed calcined sand is introduced into the oxidation chamber of the suspension roasting furnace 4 in a suspended state, and roasted at a temperature of 600℃ and an oxygen flow rate of 8m³. 3 Oxidation and decarburization were carried out under an atmosphere of / h to obtain arsenic-decarburized roasted sand; CO2 generated during the oxidation and decarburization process was detected. The C in the fine ore was completely converted into CO2 after oxidation. The residence time of the pre-oxidized and decarburized roasted sand in the oxidation chamber was 25min.

[0097] (4) The arsenic- and decarbonized roasted sand is fed into the hopper and cooled to room temperature to obtain pretreated gold ore product with a C content of 0.61% and an As removal rate of 86.91%;

[0098] (5) The pretreated concentrate was mixed with water to make a slurry with a mass concentration of 60%, and ground to -0.074 mm, accounting for 86% of the total mass. Sodium cyanide was added for leaching, with a sodium cyanide dosage of 4 kg / t and a cyanide leaching time of 20 h. The leached material was filtered to obtain a gold-containing solution, with a gold-containing solution leaching rate of 90.21%.

[0099] Example 6

[0100] A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control is carried out according to the following steps:

[0101] (1) A certain carbon- and arsenic-containing fine-grained gold ore has an Au content of 4.21 g / t, and an As and C content of 0.50% and 4.28%, respectively. The ore is crushed to a particle size of -2 mm, then ground to -0.074 mm, accounting for 85% of the total mass, and dried to obtain powder ore.

[0102] (2) The powdered ore is fed into the feeding hopper 11, which is equipped with a screw feeder 12 at the bottom. The material is filled to a certain height in the oxidation chamber. The heating system, gas supply system, feeding system and detection system are started. The powdered ore passes through the pre-oxidation chamber of the suspension roasting furnace 4 in a suspended state under the action of gas. It is heated to 500°C for oxidation and arsenic removal to obtain oxidized and arsenic-removed roasted sand. The air volume is 4m³. 3 / h, detect SO2 generated during the oxidative arsenic removal process, S and As in the ore powder are converted into SO2 and As gaseous compounds, and the residence time of the ore powder in the pre-oxidation chamber is 15min;

[0103] (3) The arsenic-removed calcined sand is introduced into the oxidation chamber of the suspension roasting furnace 4 in a suspended state, and roasted at a temperature of 700°C and an oxygen flow rate of 10 m³ / s. 3 Oxidation and decarburization were carried out under an atmosphere of / h to obtain arsenic-decarburized roasted sand; CO2 generated during the oxidation and decarburization process was detected. The C in the fine ore was completely converted into CO2 after oxidation. The residence time of the pre-oxidized and decarburized roasted sand in the oxidation chamber was 40min.

[0104] (4) The arsenic- and decarbonized roasted sand is fed into the hopper and cooled to room temperature to obtain pretreated gold ore product with a C content of 0.52% and an As removal rate of 88.61%;

[0105] (5) The pretreated concentrate was mixed with water to make a slurry with a mass concentration of 60%, and ground to -0.074 mm, accounting for 86% of the total mass. Sodium cyanide was added for leaching, with a sodium cyanide dosage of 4 kg / t and a cyanide leaching time of 30 h. The leached material was filtered to obtain a gold-containing solution, with a gold-containing solution leaching rate of 92.48%.

Claims

1. A method for enhanced sorting of fine-grained carbonaceous and arsenic-containing gold ores with segmented and precise control, characterized in that, Follow these steps: (1) The carbon- and arsenic-containing fine-grained gold ore is crushed and ground, and after drying, powder ore with a particle size of -0.074 mm accounting for 80%~90% of the total mass is obtained and placed in the feed hopper; (2) Fill the oxidation chamber of the suspension roaster to a certain height to prevent the material from escaping from the inlet. Start the heating system, gas supply system, feeding system and detection system. Under the action of gas, the ore powder passes through the pre-oxidation loosening chamber and pre-oxidation fluidization chamber of the suspension roaster in a suspended state for oxidation and arsenic removal, to obtain oxidized and arsenic-removed roasted sand. Detect the SO2 generated during the oxidation and arsenic removal process using a flue gas analyzer, and adjust the gas flow and heating temperature of the corresponding pre-oxidation loosening chamber and pre-oxidation fluidization chamber to ensure that As in the ore powder is converted into gaseous compounds. The reaction formula on which the complete reaction is based is: As2(g)+O2(g)=AsO(g) (1); FeAsS+2.5FeS2+O2=3.5FeS+0.5As2S3(g)+SO2(g) (2); FeAsS+2FeS2+O2=3FeS+0.25As4S4(g)+SO2(g) (3); FeAsS+2.5O2(g)=0.5Fe2O3+0.5As2O3(g)+SO2(g) (4); (3) The arsenic-removed roasted sand is introduced into the oxidation loosening chamber and oxidation fluidization chamber of the suspension roasting furnace in a suspended state under the action of gas for oxidation decarburization, to obtain arsenic-removed and decarburized roasted sand; the CO2 generated during the oxidation decarburization process is detected by a flue gas analyzer, and the gas flow and heating temperature of the corresponding oxidation loosening chamber and oxidation fluidization chamber are adjusted to ensure that the C in the ore powder is completely converted into CO2. The reaction formula on which the complete reaction is based is: CO2(g) + C = 2CO(g) (5; 2C + O2(g) = 2CO (6); C + O₂(g) = CO₂(g) (7; 2CO + O2(g) = 2CO2(g) (8; (4) The arsenic- and decarbonized roasted sand enters the hopper under the action of gravity to obtain pretreated gold ore products; (5) The pretreated gold ore products are fed into the grinding and leaching system for grinding-cyanide leaching. After leaching, the material is filtered to obtain gold-containing precious solution.

2. The method for enhanced separation of carbon- and arsenic-containing fine-grained gold ore with segmented and precise control according to claim 1, characterized in that, The Au content in carbon- and arsenic-containing fine-grained gold ore ranges from 2.8 g / t to 6.4 g / t, the C mass percentage ranges from 3% to 10%, and the As mass percentage ranges from 0.2% to 0.8%.

3. The method for enhanced separation of carbon- and arsenic-containing fine-grained gold ores with segmented and precise control according to claim 1, characterized in that, The heating temperature in step (2) is 500℃~600℃, the heating time is 10min~20min, and the gas introduced is air with a flow rate of 3m³. 3 / h~5m 3 / h.

4. The method for enhanced separation of carbon- and arsenic-containing fine-grained gold ore with segmented and precise control according to claim 1, characterized in that, The heating temperature in step (3) is 600℃~750℃, the heating time is 25min~50min, the gas introduced is oxygen, and the gas volume is 8m³. 3 / h~12m 3 / h.

5. The method for enhanced separation of carbon- and arsenic-containing fine-grained gold ores with segmented and precise control according to claim 1, characterized in that, The pretreated gold ore product contains less than 0.8% carbon and has a removal rate of more than 85% as particulate matter.

6. The method for enhanced separation of carbon- and arsenic-containing fine-grained gold ore with segmented and precise control according to claim 1, characterized in that, In step (5), the grinding concentration is 40%~65%, the grinding fineness is -0.074mm>85%, the amount of sodium cyanide is 0.8kg / t~10kg / t, the cyanide leaching time is 20h~30h, and the leaching rate of Au in the precious metal solution is >90%.

7. The method according to any one of claims 1-6 employs a device for segmented, precisely controlled, enhanced separation of fine-grained carbonaceous and arsenic-containing gold ore, characterized in that... It includes a feeding system, a heating system, a suspension roasting furnace, a gas supply system, a detection system, and a grinding and leaching system, wherein the feeding system, the suspension roasting furnace, and the grinding and leaching system are connected in sequence.

8. The device for segmented and precisely controlled enhanced separation of carbon- and arsenic-containing fine-grained gold ore according to claim 7, characterized in that, The interior of the suspension roasting furnace is equipped with an air distribution plate, with an oxidation chamber at the upper end and a gas chamber at the lower end. The oxidation chamber is divided into four independent reaction chambers by three baffles, which guide the gas to flow up and down. From right to left, they are: pre-oxidation loosening chamber, pre-oxidation fluidization chamber, oxidation loosening chamber, and oxidation fluidization chamber. The gas chamber is divided into four independent gas chambers by three baffles, corresponding to the positions of the four independent reaction chambers.

9. The device for segmented and precisely controlled enhanced separation of carbon- and arsenic-containing fine-grained gold ore according to claim 7, characterized in that, The feeding system includes a feeding bin and a screw feeder. The outlet of the feeding bin is connected to the inlet of the screw feeder, and the outlet of the screw feeder is connected to the upper end of the oxidation chamber in the suspension roasting furnace. The heating system includes a heater and a temperature control cabinet. The heating system is located on the outer wall of the suspension roasting furnace, and the heating temperature is precisely controlled by the temperature control cabinet. The gas supply system includes a gas tank, a gas flow meter, and an air distribution plate; the outlet of the gas tank and the lower end of the gas chamber in the suspension roasting furnace are connected through the gas flow meter. The detection system includes a gas collector, a flue gas analyzer, and a computer. The gas collector is connected to the flue gas analyzer, and the computer is assembled with the flue gas analyzer. The grinding and leaching system includes a mill and a leaching tank. The inlet of the mill is connected to the outlet of the suspension roasting furnace, and the outlet of the mill is connected to the inlet of the leaching tank.

Images