Method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings

Abstract

The invention belongs to the technical field of gold smelting, and relates to a method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings, which comprises the following steps: (1) uniformly mixing and blending ores; (2) activating an additive; (3) reducing, magnetizing and roasting; (4) recovering gold and silver through flotation; and (5) recovering iron ore concentrate through magnetic separation. The cyanidation gold extraction tailings are efficiently treated through a four-stage treatment process, the process method is simple and easy to implement, gold, sulfur and iron in the cyanidation gold extraction tailings are efficiently recycled, comprehensive utilization and clean production of the cyanidation gold extraction tailings are achieved, harm of the cyanidation gold extraction tailings to the environment is eliminated, the process flow is smooth, operability is high, the environment is excellent, and the method is suitable for industrial production. The method has remarkable economic benefits, social benefits and environmental benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of gold smelting and relates to a method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings. Background Art

[0002] Gold and silver are usually associated with minerals in the form of single elements. The main metal minerals are pyrite, arsenopyrite, etc., followed by galena, sphalerite, pyrrhotite, arsenopyrite, etc. Non-metallic minerals are quartz, feldspar and carbonate minerals. Gold and silver are closely related to pyrite and arsenopyrite, and generally form associated minerals. The main components of arsenopyrite are FeAsS, SiO 2 Etc. and trace elements such as gold and silver that accompany them.

[0003] At present, in the field of gold smelting technology, direct cyanidation gold extraction technology is generally used for easy-to-treat gold concentrates, and three pre-treatment process methods are generally used for difficult-to-treat arsenic and carbon-containing gold concentrates: one is roasting process technology; the second is hot pressing process technology; the third is biological oxidation process technology. Among them, roasting process is the main method for treating gold concentrates at present. After roasting pretreatment, cyanidation process is still used for gold extraction. Whether it is the tailings after direct cyanidation gold extraction or the tailings after cyanidation gold extraction after pretreatment, it is difficult to effectively dispose of them. In 2016, cyanidation tailings were included in the "National Hazardous Waste List". At the same time, the tailings of cyanidation gold extraction from gold concentrates contain a certain amount of sulfur, gold, and iron that have not been effectively recovered, resulting in a waste of resources. How to achieve comprehensive recovery and utilization of cyanidation gold extraction tailings has become the focus of the industry. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned prior art, the present invention provides a method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings. The specific technical scheme is as follows:

[0005] A method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings, comprising the following steps:

[0006] (1) Mixing and blending: mixing the direct cyanidation tailings and the roasting cyanidation tailings in a mass ratio of 1:1 to 3 to obtain a mixed cyanidation tailings material;

[0007] (2) Additive activation: Add additives to the mixed cyanide tailings material, the additives including lead-containing substances, sodium hydroxide, sodium sulfate, sodium sulfide and sodium carbonate; then add water to adjust the slurry concentration to 60wt% to 70wt% (based on dry ore percentage), the temperature is 60 to 70°C, and the activation is carried out under normal pressure and stirred for more than 4 hours to obtain an activated slurry;

[0008] (3) reduction magnetization roasting: the activated slurry is continuously fed into a fluidized bed furnace for reduction magnetization roasting to obtain reduction magnetization roasted sand and flue gas; the temperature of the reduction magnetization roasting is 850-900°C, the furnace bottom pressure is 12000-16000Pa, and the air excess coefficient is controlled at 0.8-1.0;

[0009] (4) Flotation recovery of gold and silver: After reducing the magnetized roasted sand for grinding, sodium sulfide, sodium carbonate and copper sulfate are added, butyl xanthate and butyl ammonium black powder are used as collectors, and the pulp concentration is adjusted to 20-30wt%. After a roughing selection, a second scavenging selection and a second concentrating process, gold concentrate and flotation tailings are produced;

[0010] (5) Magnetic separation to recover iron concentrate: The concentration of flotation tailings slurry is adjusted to 18-28wt% and then fed into a magnetic separator with a high magnetic induction intensity of 1200-1500 Gauss. A primary roughing and secondary fine separation magnetic separation process is adopted to produce iron concentrate and tailings after magnetic separation.

[0011] The direct cyanidation tailings of the present invention contain 0.8-1.60g / t of gold, 5-15g / t of silver, 20-30wt% of sulfur and 15-25wt% of iron; the roasted cyanidation tailings contain 1.5-5.5g / t of gold, 20-50g / t of silver, 0.5-1.5wt% of sulfur and 25-40wt% of iron. Step (3) The reduction magnetization roasting in the boiling furnace is carried out in an oxygen-deficient roasting manner so that most of the sulfur is oxidized into sulfur dioxide SO 2 It enters the flue gas in the form of gas, and a small amount enters the slag and smoke in the form of sulfate; at the same time, it converts the iron in the cyanide gold extraction tailings into magnetic iron Fe 3 O 4 , the ore particles become porous and loose; the gold-encapsulating compounds such as sulfides, metal oxides, and silicon dioxide are effectively decomposed, and the mineral structure is accurately transformed. The reduced magnetized roasted sand obtained in step (3) contains 2.5-4.5g / t gold, 20-40g / t silver, 0.2-0.5wt% sulfur, and 25-35wt% iron. Step (4) can obtain a gold concentrate containing 30-50g / t gold and 230-380g / t silver, and the gold concentrate is returned to the gold extraction system; as well as a flotation tailing containing 0.5g / t gold, 10g / t silver, and 35-40wt% iron. Step (5) can produce an iron concentrate containing 60-63wt% iron, and the iron recovery rate reaches 92-94%. The tailings after magnetic separation are used as raw materials for building materials production.

[0012] The present invention efficiently treats the cyanidation gold tailings through a four-stage treatment process, the first stage is the precise control and uniform mixing of direct cyanidation tailings and roasting cyanidation tailings, the second stage is the addition of additives for activation, the third stage is the reduction magnetization roasting, and the roasting flue gas is used to make acid to recover sulfur; the fourth stage is the roasting sand grinding flotation technology to recover gold and silver; the fifth stage is the flotation tailings magnetic separation to recover iron concentrate, and the magnetic separation tailings produced at the same time are high-silicon slags, which are used as raw materials for building materials production. The present invention enables the gold, sulfur and iron in the cyanidation gold tailings to be efficiently recovered, realizes the comprehensive utilization and clean production of the cyanidation gold tailings, eliminates the harm of the cyanidation gold tailings to the environment, has a smooth process flow, strong operability, and a good environment, and has significant economic benefits, social benefits, and environmental benefits.

[0013] Furthermore, in the step (1), the stirring speed is 20 to 40 r / min, and the mixing time is 1 to 3 h.

[0014] Furthermore, in step (2), the lead-containing substance is a lead-containing mineral and / or lead copper nitrate, and the lead-containing substance serves as an activator.

[0015] Furthermore, in the step (2), the additive is added in an amount of 30-50 kg / t, the lead content in the additive accounts for 0.2-0.4 wt % of the mixed cyanide tailings material, and the weight ratio of the sodium hydroxide, sodium sulfate, sodium sulfide and sodium carbonate is 1:1:1:3.

[0016] Furthermore, the flue gas obtained in step (3) is subjected to dry dust removal, wet dust removal, electrostatic precipitator, conversion, and dry absorption processes to produce industrial sulfuric acid.

[0017] Furthermore, in the step (4), the grinding time is 10 to 15 minutes, and the grinding fineness of -0.074 mm accounts for 90 to 95%.

[0018] Furthermore, in step (4), the amount of sodium sulfide added is 200-400 g / t, the amount of sodium carbonate is 200-400 g / t, the amount of copper sulfate is 300-500 g / t, the amount of butyl xanthate is 80-120 g / t, and the amount of butyl ammonium black medicine is 40-60 g / t.

[0019] The beneficial effects of the present invention are:

[0020] The process method of the invention is simple and easy to implement, and is suitable for both direct cyanidation gold extraction tailings and roasting cyanidation tailings of gold concentrate; the direct cyanidation gold extraction tailings and roasting cyanidation tailings are finely controlled and matched, which is beneficial to ensuring the combustion heat of subsequent reduction roasting and making the production balanced and orderly; the lead-containing minerals or lead salts increase and enrich the gold and silver particles of the cyanidation gold extraction tailings during the roasting process, which is beneficial for the gold and silver to enter the concentrate during the subsequent flotation process, so that the flotation recovery rate of gold and silver can be greatly improved; the reduction magnetization roasting can efficiently convert the iron in the cyanidation gold extraction tailings into magnetic iron, and the tailings after the gold and silver are recovered by flotation can further recover the iron by adopting an efficient magnetic separation process.

[0021] The present invention enables gold, sulfur and iron in cyanidation gold extraction tailings to be efficiently recovered, realizes the comprehensive utilization and clean production of cyanidation gold extraction tailings, eliminates the harm of cyanidation gold extraction tailings to the environment, has a smooth process flow, strong operability, good environment, and significant economic benefits, social benefits, and environmental benefits. DETAILED DESCRIPTION

[0022] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0023] Embodiment 1:

[0024] A method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings, comprising the following steps:

[0025] (1) Precisely controlled mixing and blending: According to the composition and characteristics of cyanidation tailings, the direct cyanidation tailings contain 0.8 g / t of gold, 5 g / t of silver, 20 wt% of sulfur, and 15 wt% of iron; the roasted cyanidation tailings contain 1.5 g / t of gold, 20 g / t of silver, 0.5 wt% of sulfur, and 25 wt% of iron; the direct cyanidation tailings and the roasted cyanidation tailings are stirred and mixed in a mass ratio of 1:1, with a stirring speed of 20 r / min and a mixing time of 1 h. After mixing, the mixed cyanidation tailings material enters the next stage of the process;

[0026] (2) Additive activation: Add additives to the mixed cyanide tailings material in an amount of 30 kg / t. The additives are lead nitrate, a lead-containing substance, and sodium hydroxide, sodium sulfate, sodium sulfide, and sodium carbonate compounds; the lead content accounts for 0.2 wt% of the mixed minerals, and the weight ratio of sodium hydroxide, sodium sulfate, sodium sulfide, and sodium carbonate is 1:1:1:3. Water is then added to adjust the slurry concentration to 60 wt% (based on dry ore percentage), the temperature is 60° C., and the activation is carried out under normal pressure for more than 4 hours to obtain an activated slurry; after stirring, the slurry enters the next step;

[0027] (3) Reduction magnetization roasting: The activated slurry is continuously fed into the boiling furnace, the reduction temperature is controlled at 850°C, the furnace bottom pressure is 12000Pa, the blower is controlled to blow steadily, the air excess coefficient is controlled at 0.8, and the oxygen-deficient roasting is maintained so that most of the sulfur is oxidized into sulfur dioxide SO 2 It enters the flue gas in the form of gas, and is processed through dry dust removal, wet dust removal, electrostatic dust removal, conversion, and dry absorption to produce industrial sulfuric acid. A small amount of it enters the slag and smoke in the form of sulfate. At the same time, it converts the iron in the tailings of cyanide gold extraction into magnetic iron Fe 3 O 4 , the ore particles become porous and loose; the gold-encapsulating compounds such as sulfides, metal oxides, and silicon dioxide are effectively decomposed, and the mineral structure is accurately transformed; the reduced magnetized roasted sand contains 2.5g / t gold, 20g / t silver, 0.2wt% sulfur, and 25wt% iron, and enters the next level of process;

[0028] (4) Flotation recovery of gold and silver: the reduced magnetized roasted sand is fed into a wet overflow mill, the grinding time is 10 min, the grinding fineness is -0.074 mm accounting for 90%, 200 g / t of sodium sulfide, 200 g / t of sodium carbonate, 300 g / t of copper sulfate are added, butyl xanthate and butyl ammonium black powder are used as collectors, the dosages are 80 g / t and 40 g / t respectively, the pulp concentration is adjusted to 20 wt%, and after a roughing selection, a secondary scavenging selection and a secondary concentrating process, a gold concentrate containing 30 g / t of gold and 230 g / t of silver is produced, and the gold concentrate is returned to the gold extraction system; the flotation tailings containing 0.5 g / t of gold, 10 g / t of silver and 35 wt% of iron enter the next stage of the process;

[0029] (5) Magnetic separation to recover iron concentrate: The flotation tailings slurry concentration is adjusted to 18wt% and enters the CTB1024 magnetic separator with a high magnetic induction intensity of 1200 Gauss. A primary roughing and secondary fine separation magnetic separation process is adopted to produce an iron concentrate containing 60wt% iron, with an iron recovery rate of 92%. The tailings after magnetic separation are used as raw materials for building materials production.

[0030] Embodiment 2:

[0031] A method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings, comprising the following steps:

[0032] (1) Precisely controlled mixing and blending: According to the composition and characteristics of cyanidation tailings, the direct cyanidation tailings contain 1.15 g / t of gold, 10 g / t of silver, 25 wt% of sulfur, and 20 wt% of iron; the roasted cyanidation tailings contain 3.5 g / t of gold, 35 g / t of silver, 1.0 wt% of sulfur, and 32.5 wt% of iron; the direct cyanidation tailings and the roasted cyanidation tailings are stirred and mixed in a mass ratio of 1:2, with a stirring speed of 30 r / min and a mixing time of 2 h. After mixing, the mixed cyanidation tailings material enters the next stage of the process;

[0033] (2) Additive activation: Add additives in an amount of 40 kg / t to the mixed cyanide tailings material. The additives are lead nitrate, a lead-containing substance, and sodium hydroxide, sodium sulfate, sodium sulfide, and sodium carbonate compounds; the lead content accounts for 0.3 wt% of the mixed minerals, and the weight ratio of sodium hydroxide, sodium sulfate, sodium sulfide, and sodium carbonate is 1:1:1:3. Water is then added to adjust the slurry concentration to 65 wt% (based on dry ore percentage), the temperature is 65° C., and the activation is carried out under normal pressure for more than 4 hours to obtain an activated slurry; after stirring, the slurry enters the next step;

[0034] (3) Reduction magnetization roasting: The activated slurry is continuously fed into the boiling furnace, the reduction temperature is controlled at 875°C, the furnace bottom pressure is 14000Pa, the blower is controlled to blow steadily, the air excess coefficient is controlled at 0.9, and the oxygen-deficient roasting is maintained, so that most of the sulfur is oxidized into sulfur dioxide SO 2 It enters the flue gas in the form of gas, and is processed through dry dust removal, wet dust removal, electrostatic dust removal, conversion, and dry absorption to produce industrial sulfuric acid. A small amount of it enters the slag and smoke in the form of sulfate. At the same time, it converts the iron in the tailings of cyanide gold extraction into magnetic iron Fe 3 O 4 , the ore particles become porous and loose; the gold-encapsulating compounds such as sulfides, metal oxides, and silicon dioxide are effectively decomposed, and the mineral structure is accurately transformed; the reduced magnetized roasted sand contains 3.5g / t gold, 30g / t silver, 0.35wt% sulfur, and 20wt% iron, and enters the next level of process;

[0035] (4) Flotation recovery of gold and silver: the reduced magnetized roasted sand is fed into a wet overflow mill, the grinding time is 12.5 min, the grinding fineness is -0.074 mm accounting for 92.5%, 300 g / t of sodium sulfide, 300 g / t of sodium carbonate, 400 g / t of copper sulfate are added, butyl xanthate and butyl ammonium black powder are used as collectors, the dosages are 100 g / t and 50 g / t respectively, the pulp concentration is adjusted to 25 wt%, and after a roughing selection, a secondary scavenging selection and a secondary concentrating process, a gold concentrate containing 40 g / t of gold and 310 g / t of silver is produced, and the gold concentrate is returned to the gold extraction system; the flotation tailings containing 0.5 g / t of gold, 10 g / t of silver and 37.5 wt% of iron enter the next stage of the process;

[0036] (5) Magnetic separation to recover iron concentrate: The flotation tailings slurry concentration is adjusted to 23wt% and fed into the CTB1024 magnetic separator with a high magnetic induction intensity of 1350 Gauss. A primary roughing and secondary fine separation magnetic separation process is adopted to produce an iron concentrate containing 61.5wt% iron, with an iron recovery rate of 93%. The tailings after magnetic separation are used as raw materials for building materials production.

[0037] Embodiment 3:

[0038] A method for comprehensively recovering gold, sulfur and iron from cyanidation gold extraction tailings, comprising the following steps:

[0039] (1) Precisely controlled mixing and blending: According to the composition and characteristics of cyanidation tailings, the direct cyanidation tailings contain 1.60 g / t of gold, 15 g / t of silver, 30 wt% of sulfur, and 25 wt% of iron; the roasted cyanidation tailings contain 5.5 g / t of gold, 50 g / t of silver, 1.5 wt% of sulfur, and 40 wt% of iron; the direct cyanidation tailings and the roasted cyanidation tailings are stirred and mixed in a mass ratio of 1:3, the stirring speed is 40 r / min, the mixing time is 3 h, and the mixed cyanidation tailings material after mixing enters the next stage process;

[0040] (2) Additive activation: Add additives in an amount of 50 kg / t to the mixed cyanide tailings material. The additives are lead nitrate, a lead-containing substance, and sodium hydroxide, sodium sulfate, sodium sulfide, and sodium carbonate compounds; the lead content accounts for 0.4 wt% of the mixed minerals, and the weight ratios of sodium hydroxide, sodium sulfate, sodium sulfide, and sodium carbonate are 1:1:1:3, respectively. Water is then added to adjust the slurry concentration to 70 wt% (based on dry ore percentage), the temperature is 70° C., and the activation is carried out under normal pressure for more than 4 hours to obtain an activated slurry; after stirring, the slurry enters the next step;

[0041] (3) Reduction magnetization roasting: The activated slurry is continuously fed into the boiling furnace, the reduction temperature is controlled at 900°C, the furnace bottom pressure is 16000Pa, the blower is controlled to blow steadily, the air excess coefficient is controlled at 1.0, and the oxygen-deficient roasting is maintained so that most of the sulfur is oxidized into sulfur dioxide SO 2 It enters the flue gas in the form of gas, and is processed through dry dust removal, wet dust removal, electrostatic dust removal, conversion, and dry absorption to produce industrial sulfuric acid. A small amount of it enters the slag and smoke in the form of sulfate. At the same time, it converts the iron in the tailings of cyanide gold extraction into magnetic iron Fe 3 O 4 , the ore particles become porous and loose; the gold-encapsulating compounds such as sulfides, metal oxides, and silicon dioxide are effectively decomposed, and the mineral structure is accurately transformed; the reduced magnetized roasted sand contains 4.5g / t gold, 40g / t silver, 0.5wt% sulfur, and 35wt% iron, and enters the next level of process;

[0042] (4) Flotation recovery of gold and silver: the reduced magnetized roasted sand is fed into a wet overflow mill, the grinding time is 15 min, the grinding fineness is -0.074 mm accounting for 95%, 400 g / t of sodium sulfide, 400 g / t of sodium carbonate, 500 g / t of copper sulfate are added, butyl xanthate and butyl ammonium black powder are used as collectors, the dosages are 120 g / t and 60 g / t respectively, the pulp concentration is adjusted to 30 wt%, and after a roughing selection, a secondary scavenging selection and a secondary concentrating process, a gold concentrate containing 50 g / t of gold and 380 g / t of silver is produced, and the gold concentrate is returned to the gold extraction system; the flotation tailings containing 0.5 g / t of gold, 10 g / t of silver and 40 wt% of iron enter the next stage of the process;

[0043] (5) Magnetic separation to recover iron concentrate: The flotation tailings slurry concentration is adjusted to 28wt% and fed into the CTB1024 magnetic separator with a high magnetic induction intensity of 1500 Gauss. A primary roughing and secondary fine separation magnetic separation process is adopted to produce an iron concentrate containing 63wt% iron, with an iron recovery rate of 94%. The tailings after magnetic separation are used as raw materials for building materials production.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for comprehensive recovery of gold, sulfur and iron from cyanide gold extraction tailings, characterized in that: The steps include: (1) Mixing and blending: mixing the direct cyanidation tailings and the roasting cyanidation tailings in a mass ratio of 1:1 to 3 to obtain a mixed cyanidation tailings material; (2) Additive activation: Add additives to the mixed cyanide tailings material, the additives including lead-containing substances, sodium hydroxide, sodium sulfate, sodium sulfide and sodium carbonate; then add water to adjust the slurry concentration to 60wt% to 70wt% (based on dry ore percentage), the temperature is 60 to 70°C, and the activation is carried out under normal pressure and stirred for more than 4 hours to obtain an activated slurry; (3) reduction magnetization roasting: the activated slurry is continuously fed into a fluidized bed furnace for reduction magnetization roasting to obtain reduction magnetization roasted sand and flue gas; the temperature of the reduction magnetization roasting is 850-900°C, the furnace bottom pressure is 12000-16000Pa, and the air excess coefficient is controlled at 0.8-1.0; (4) Flotation recovery of gold and silver: After reducing the magnetized roasted sand for grinding, sodium sulfide, sodium carbonate and copper sulfate are added, butyl xanthate and butyl ammonium black powder are used as collectors, and the pulp concentration is adjusted to 20-30wt%. After a roughing selection, a second scavenging selection and a second concentrating process, gold concentrate and flotation tailings are produced; (5) Magnetic separation to recover iron concentrate: The concentration of flotation tailings slurry is adjusted to 18-28wt% and then fed into a magnetic separator with a high magnetic induction intensity of 1200-1500 Gauss. A primary roughing and secondary fine separation magnetic separation process is adopted to produce iron concentrate and tailings after magnetic separation.

2. The method for comprehensive recovery of gold, sulfur and iron from cyanide gold extraction tailings according to claim 1, characterized in that: In the step (1), the stirring speed is 20 to 40 r / min, and the mixing time is 1 to 3 hours.

3. The method for comprehensive recovery of gold, sulfur and iron from cyanide gold extraction tailings according to claim 1, characterized in that: In the step (2), the lead-containing substance is a lead-containing mineral and / or lead nitrate.

4. The method for comprehensive recovery of gold, sulfur and iron from cyanide gold extraction tailings according to claim 1, characterized in that: In the step (2), the additive is added in an amount of 30-50 kg / t, the lead content of the additive accounts for 0.2-0.4 wt % of the mixed cyanide tailings material, and the weight ratio of the sodium hydroxide, sodium sulfate, sodium sulfide and sodium carbonate is 1:1:1:

3.

5. The method for comprehensive recovery of gold, sulfur and iron from cyanide gold extraction tailings according to claim 1, characterized in that: The flue gas obtained in step (3) is subjected to dry dust removal, wet dust removal, electrostatic dust removal, conversion, and dry absorption processes to produce industrial sulfuric acid.

6. The method for comprehensive recovery of gold, sulfur and iron from cyanide gold extraction tailings according to claim 1, characterized in that: In the step (4), the grinding time is 10 to 15 minutes, and the grinding fineness of -0.074 mm accounts for 90 to 95%.

7. The method for comprehensive recovery of gold, sulfur and iron from cyanide gold extraction tailings according to claim 1, characterized in that: In the step (4), the amount of sodium sulfide added is 200-400 g / t, the amount of sodium carbonate is 200-400 g / t, the amount of copper sulfate is 300-500 g / t, the amount of butyl xanthate is 80-120 g / t, and the amount of butyl ammonium black medicine is 40-60 g / t.