A comprehensive recovery method for complex and difficult-to-treat multi-metal roasted sand

Abstract

The present invention relates to a comprehensive recovery method for complex and difficult-to-process multi-metal roasted sand, comprising the following steps: (1) secondary roasting to remove arsenic and sulfur; (2) cold extraction treatment; (3) acid leaching to recover copper and zinc; (4) ultrasonic NaOH alkaline leaching enhanced pretreatment; and (5) intermittent ultrasonic-gold cicada leaching of gold and silver. The "roasting-cold extraction-acid leaching-ultrasonic NaOH alkaline leaching-ultrasonic gold cicada leaching" combined process provided by the present invention is targeted at complex and difficult-to-process multi-metal roasted sand. The process firstly pre-treats the gold and silver inclusions with high temperature roasting, acid leaching and ultrasonic alkaline leaching, so that the impurities and arsenic and sulfur in the symbiotic intergrowth are preferentially removed under high temperature, strong acid and strong alkaline conditions. At the same time, the cold extraction treatment destroys the structure of the gold and silver inclusions, forming a loose and porous structure. Under the cavitation effect of ultrasonic waves, the arsenic and sulfur can be removed to the greatest extent. Then, intermittent ultrasonic waves and gold cicada reagents are used to efficiently leach the gold and silver, thereby obtaining valuable elements of gold, silver, copper, zinc and iron with a high leaching rate.

Description

Technical Field

[0001] The invention belongs to the technical field of multi-metal roasted sand recovery, and in particular relates to a comprehensive recovery method for complex and difficult-to-process multi-metal roasted sand. Background Art

[0002] A complex and difficult-to-process multi-metallic roasted sand contains 3.95g / t gold, 34.58g / t silver, 0.32% copper, 0.38% zinc, 0.55% arsenic, 2.63% sulfur, and 57.64% iron. The roasted sand is primarily composed of ferric oxide, with minor amounts of quartz, gypsum, potassium feldspar, biotite, and chlorite. The gold minerals in the roasted sand are native gold and silver-gold ores, while the silver minerals are primarily silver ore, with minor amounts of sulfide-copper-silver ores and trace amounts of silver-gold ores. The gold minerals are concentrated in particle sizes below 20µm, with gold minerals smaller than 1µm accounting for a high proportion of 29.25%. Silver and arsenic are also finely distributed, with a high concentration in the fine particle size below 8µm, with distribution ratios of 54.09% and 60.30%, respectively. Approximately 50% or more of the gold and silver minerals are encapsulated in ferric oxide and gangue minerals.

[0003] The current method for recovering gold and silver from this type of multi-metal roasted sand is a "water washing-cyanide leaching" process. The gold leaching rate is generally 70.00%, and the silver leaching rate is 30% to 40%. The cyanide tailings are mainly iron concentrate (with an iron grade of 58.31%, an arsenic grade of 0.47%, and a sulfur grade of 1.30%). Therefore, the following problems exist when implementing this recovery process:

[0004] (1) Since gold and silver exist in the form of fine-grained inclusions, they cannot effectively contact the leaching agent during the cyanidation process, resulting in low gold and silver leaching rates. The gold leaching rate is only 70.00% and the silver leaching rate is only 30% to 40%.

[0005] (2) The high copper and zinc content in roasted sand was not effectively recovered, resulting in resource loss. In addition, due to the high copper content, the consumption of sodium cyanide in the cyanidation operation was high (the unit consumption was 3 kg / t), which increased the amount of reagents used.

[0006] (3) Roasted sand contains high levels of harmful elements arsenic and sulfur. The existing process is not effective in removing arsenic and sulfur, resulting in high levels of arsenic and sulfur in the final iron ore concentrate, which affects the quality and sales of the iron ore concentrate.

[0007] (4) The use of highly toxic sodium cyanide as a reagent for leaching gold and silver poses a great threat to the workers and the environment, and also puts great pressure on the transportation, storage, and environmental protection of the reagents during the production process. Summary of the Invention

[0008] To address the above problems, the present invention provides a comprehensive recovery method for complex and difficult-to-process multi-metal roasted sand to improve the leaching rate of gold and silver in the multi-metal roasted sand, recover copper and zinc in the roasted sand, reduce the content of harmful elements such as arsenic and sulfur, and ultimately obtain high-quality iron ore concentrate.

[0009] The specific technical solution is: a comprehensive recovery method for complex and difficult-to-treat multi-metal roasted sand, including the following steps:

[0010] (1) Secondary roasting to remove arsenic and sulfur: roast the calcined sand in a furnace to further remove harmful impurities such as arsenic and sulfur at high temperature;

[0011] (2) Cold extraction: The roasted sand at high temperature after calcination is directly placed in cold water for cold extraction. The principle of thermal expansion and contraction is used to make the high-temperature roasted sand extremely shrink and break in cold water, thereby destroying the gold and silver inclusions and forming a loose porous structure in the roasted sand, effectively increasing its contact surface area. After the cold extraction is completed, it is filtered;

[0012] (3) Acid leaching method for copper and zinc recovery: The roasted sand obtained by cold extraction and filtration is transferred to an acid leaching stirring tank and water is added to prepare a pulp. After the pulp is evenly stirred, sulfuric acid is added and heated for acid leaching to obtain an acid leaching solution and an acid leaching residue. The leached copper, zinc, arsenic and sulfur enter the acid leaching solution, thereby achieving the leaching of copper and zinc and further removal of part of the arsenic and sulfur. The acid leaching residue is then washed and filtered to clean the leached copper, zinc, arsenic and sulfur. After washing, the acid leaching residue is dried.

[0013] (4) Ultrasonic NaOH alkaline leaching enhanced pretreatment: The dried acid leaching residue is transferred to a leaching stirring tank and water is added to make pulp. After the pulp is evenly stirred, sodium hydroxide is added. The ultrasonic device is started while heating the alkaline leaching. Alkaline leaching liquid and alkaline leaching residue are obtained by ultrasonic leaching. The leached arsenic and sulfur enter the alkaline leaching liquid, thus achieving further removal of arsenic and sulfur. The alkaline leaching residue is then washed and filtered to clean the leached arsenic and sulfur. After washing, the alkaline leaching residue is dried.

[0014] An ultrasonic device is added during the alkaline leaching process, and the cavitation effect of ultrasound in the liquid is used to disperse the acid leaching residue as much as possible, improve the stripping and removal of arsenic and sulfur elements in the acid leaching residue, strengthen pretreatment, and create good conditions for subsequent leaching of gold and silver.

[0015] (5) Intermittent ultrasonic-Jinchan leaching: Add the dried alkaline leaching residue into the leaching stirring tank and add water to make pulp. After the slurry is evenly stirred, lime is added to adjust the pH value to 11-12, and then Jinchan reagent is added. At the same time, the ultrasonic device is started. During the leaching process of the Jinchan reagent, the ultrasonic device is started and stopped intermittently. The leaching obtains precious liquid and cyanide slag, in which gold and silver enter the precious liquid in the form of complexes, that is, the leaching of gold and silver is achieved; then the cyanide slag is washed and filtered to clean the leached gold and silver. After washing, the cyanide slag is dried to obtain iron concentrate.

[0016] For the leaching of gold and silver under ultrasonic conditions, the Golden Cicada agent is used instead of the highly toxic sodium cyanide agent to leach the gold and silver in the alkaline leaching residue. This not only improves the leaching rate of gold and silver, but also, as a new type of environmentally friendly mineral processing agent, the Golden Cicada agent can greatly alleviate the harm caused by toxic agents.

[0017] Furthermore, in step (1), the roasting temperature is 600° C., the roasting time is 2 h, and the furnace door is slightly opened during roasting to ensure that air can enter.

[0018] Furthermore, the liquid-to-solid ratio of the cold extraction treatment in step (2) is 3:1.

[0019] Furthermore, in step (2), stirring is started during the cold extraction process, and the stirring speed is 1200 r / min.

[0020] Furthermore, the cold extraction treatment time in step (2) is 2 hours.

[0021] Furthermore, in step (3), the liquid-to-solid ratio of the slurry is 1.5:1, and the rotation speed of the stirring device is 800 r / min.

[0022] Furthermore, the amount of sulfuric acid used in step (3) is 380 kg / t.

[0023] Furthermore, in step (3), the acid leaching temperature is 90° C. and the acid leaching time is 2 h.

[0024] Furthermore, the liquid-to-solid ratio of the acid leaching residue washing in step (3) is 5:1.

[0025] Furthermore, in step (4), the liquid-to-solid ratio of the slurry is 1.5:1, and the rotation speed of the stirring device is 800 r / min.

[0026] Furthermore, the amount of sodium hydroxide used in step (4) is 160 kg / t.

[0027] Furthermore, in step (4), the alkali leaching temperature is 90° C. and the alkali leaching time is 3 h.

[0028] Furthermore, the liquid-to-solid ratio of the alkaline leaching residue washing in step (4) is 5:1.

[0029] Furthermore, the intensity of the ultrasonic device in step (4) is 200W.

[0030] Furthermore, the start and stop control of the ultrasonic device in step (5) is specifically to start when the Jinchan agent is added, shut down after 2 hours of ultrasonic leaching, and start again after 4 hours of leaching, that is, the ultrasonic wave is turned on for 2 hours and stopped for 4 hours, and this cycle is repeated until the ultrasonic wave is turned on for a total of 6 hours, at which time the ultrasonic wave is stopped.

[0031] Furthermore, the intensity of the ultrasonic device in step (5) is 200W.

[0032] Furthermore, the leaching time of the golden cicada agent in step (5) is 24 hours.

[0033] Furthermore, the amount of lime used in step (5) is 6 kg / t.

[0034] Furthermore, the dosage of the golden cicada agent in step (5) is 1.5 kg / t.

[0035] Furthermore, the liquid-solid ratio of the cyanide slag washing in step (5) is 5:1.

[0036] Beneficial effects of the present invention:

[0037] (1) The combined process of "roasting-cold extraction-acid leaching-ultrasonic NaOH alkaline leaching-ultrasonic gold cicada leaching" provided by the present invention can comprehensively recover the valuable elements gold, silver, copper, zinc, and iron from complex and difficult-to-treat multi-metal roasted sand, and remove harmful elements arsenic and sulfur. The leaching rate of valuable elements and the removal rate of harmful elements are significantly better than those of the existing technology, and the comprehensive resource recovery and utilization rate and economic benefits are significantly improved.

[0038] (2) The present invention pre-treats complex and difficult-to-process multi-metal roasted sand by high-temperature roasting, acid leaching, and ultrasonic alkaline leaching, so that the impurities in the gold and silver inclusions and the arsenic and sulfur in the symbiotic bodies are preferentially removed under high temperature, strong acid, and strong alkaline conditions. At the same time, the cold extraction treatment destroys the structure of the gold and silver inclusions, forming a loose and porous structure, increasing its contact surface area. Under the support of ultrasonic cavitation, the removal rate of arsenic and sulfur can be significantly improved, and the roasted sand structure can be made more dispersed, providing a roasted sand structure that is easier to leach for subsequent gold and silver leaching.

[0039] (3) The present invention preferentially leaches copper and zinc during the acid leaching process, thereby achieving copper and zinc recovery and reducing the reagent consumption in the gold and silver leaching process.

[0040] (4) The pre-treated roasted sand is then leached with intermittent ultrasonic wave and golden cicada reagent to extract gold and silver, which can effectively improve the leaching rate of gold and silver and obtain high-quality iron concentrate. In addition, the environmentally friendly golden cicada reagent replaces the highly toxic sodium cyanide reagent, which is more environmentally friendly and healthy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flow chart of a comprehensive recovery method for complex and difficult-to-process multi-metal roasted sand. DETAILED DESCRIPTION

[0042] In order to make the technical problems and technical solutions solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] Roasted ore: A complex and difficult-to-process polymetallic roasted ore containing 3.95g / t gold, 34.58g / t silver, 0.32% copper, 0.38% zinc, 0.55% arsenic, 2.63% sulfur, and 57.64% iron. The roasted ore is primarily composed of ferric oxide, with minor amounts of quartz, gypsum, potassium feldspar, biotite, and chlorite. The gold minerals in the roasted ore are native gold and silver-gold ores, while the silver minerals are primarily silver ore, with minor amounts of sulfide-copper-silver ores and trace amounts of silver-gold ores. The gold minerals are concentrated in particle sizes below 20µm, with gold minerals smaller than 1µm accounting for a high proportion of 29.25%. Silver and arsenic are finer in particle size, with a higher concentration in the finer particle size below 8µm, accounting for 54.09% and 60.30%, respectively. Approximately 50% or more of the gold and silver minerals are encapsulated in ferric oxide and gangue minerals.

[0044] After elemental analysis of the roasted sand, it was found that the metals that need to be recovered in the roasted sand are gold, silver, copper, zinc, and iron, and the harmful elements that need to be removed are arsenic and sulfur. Since gold and silver exist in the roasted sand as fine-grained inclusions, they cannot effectively contact the leaching agent during the cyanidation process, resulting in a low leaching rate of gold and silver. In addition, gold, silver and arsenic are symbiotically embedded, and the embedded particle size of arsenic is also relatively fine. Therefore, the present invention adopts a combined process of "roasting-cold extraction-acid leaching-ultrasonic NaOH alkaline leaching-ultrasonic gold cicada leaching" to comprehensively recover the above-mentioned roasted sand. The specific implementation steps are as follows:

[0045] (1) Secondary roasting to remove arsenic and sulfur: Set the roasting temperature of the muffle furnace to 600℃, start the muffle furnace to heat up, and when the temperature reaches 600℃, put the weighed roasted sand into the muffle furnace for roasting. At the same time, ensure that the muffle furnace door is slightly open to allow air to enter. After roasting for 2 hours, close the muffle furnace and end the roasting. The roasted sand undergoes secondary roasting under high temperature conditions to further remove some of the harmful impurities arsenic and sulfur, while preparing for the subsequent roasted sand cold extraction.

[0046] (2) Cold extraction: The roasted sand at high temperature after calcination is directly placed in cold water for cold extraction, wherein the liquid-solid ratio of water to roasted sand is 3:1. The principle of thermal expansion and contraction is used to make the high-temperature roasted sand extremely shrink and break in cold water, thereby destroying the gold and silver inclusions and forming a loose porous structure in the roasted sand, effectively increasing its contact specific surface area. During the cold extraction process, stirring is started at a speed of 1200 r / min. The cold extraction is terminated after 2 hours, and the roasted sand is filtered;

[0047] (3) Acid leaching method to recover copper and zinc: The roasted sand obtained by cold extraction filtration is transferred to the acid leaching stirring tank and water is added to make pulp. When making pulp, the corresponding amount of water is added at a liquid-solid ratio of 1.5:1, and stirring is started at the same time. The stirring speed is 800r / min. After the slurry is stirred evenly, the required amount of sulfuric acid is calculated according to the sulfuric acid unit consumption of 380kg / t, and it is added to the acid leaching stirring tank and stirred evenly. At this time, the heating device is started for heating. When the temperature of the slurry rises to 90℃, the timing is started and the slurry temperature is maintained at 90℃. After leaching for 2 hours, the heating and stirring are stopped. After the acid leaching is completed, the slurry is taken out and filtered to obtain the acid leaching solution and acid leaching residue. The leached copper, zinc, arsenic and sulfur enter the acid leaching solution, that is, the leaching of copper and zinc and the removal of part of arsenic and sulfur are achieved. The acid leaching residue is then washed and filtered. The liquid-solid ratio of the washing is 5:1. The leached copper, zinc, arsenic and sulfur are washed clean. After washing, the acid leaching residue is dried;

[0048] (4) Ultrasonic NaOH alkali leaching enhanced pretreatment: The dried acid leaching residue is transferred to the leaching stirring tank and water is added to make pulp. When making pulp, the corresponding amount of water is added at a liquid-solid ratio of 1.5:1, and stirring is started at the same time. The stirring speed is 800r / min. After the slurry is stirred evenly, the required amount of sodium hydroxide is calculated according to the sodium hydroxide unit consumption of 160kg / t, and it is added to the leaching stirring tank and stirred evenly. At this time, the heating device and ultrasonic device are started (ultrasonic intensity is 200W). When the temperature of the slurry rises to 90℃, the timing is started and the slurry temperature is maintained at 90℃. After 3 hours of ultrasonic leaching, the heating, stirring and ultrasonic device are stopped. After the alkali leaching is completed, the slurry is taken out and filtered to obtain alkali leaching solution and alkali leaching residue. The leached arsenic and sulfur enter the alkali leaching solution, that is, the arsenic and sulfur are further removed; then the alkali leaching residue is washed and filtered, and the washing liquid-solid ratio is 5:1 to wash away the leached arsenic and sulfur. After the washing is completed, the alkali leaching residue is dried;

[0049] An ultrasonic device is added during the alkaline leaching process, and the cavitation effect of ultrasound in the liquid is used to disperse the acid leaching residue as much as possible, improve the stripping and removal of arsenic and sulfur elements in the acid leaching residue, strengthen pretreatment, and create good conditions for subsequent leaching of gold and silver.

[0050] (5) Intermittent ultrasonic-Jinchan leaching: Add the dried alkaline leaching residue to the leaching stirring tank and add water to make pulp. When making pulp, add the corresponding amount of water according to the liquid-solid ratio of 2:1, and start stirring at the same time. The stirring speed is 1200r / min. After the slurry is stirred evenly, the required amount of lime is calculated according to the unit consumption of 6kg / t of lime, and it is added to the leaching stirring tank and stirred evenly. After the pH value of the slurry is adjusted to 11-12, the required amount of Jinchan agent is calculated according to the unit consumption of 1.5kg / t of Jinchan, and it is added to the leaching stirring tank and stirred evenly. At this time, start the ultrasonic device (ultrasonic intensity is 200W) and start timing. After 2 hours of ultrasonic leaching, turn off the ultrasonic wave. After 4 hours of leaching, start the ultrasonic wave again, that is, turn on for 2 hours and stop for 4 hours, and repeat this cycle until the ultrasonic wave is turned on for a total of 6 hours. Then stop the ultrasonic wave. When the Jinchan agent has been leached for 24 hours, stop stirring and the leaching is completed. After leaching is completed, the slurry is taken out and filtered to obtain precious liquid and cyanide slag, in which gold and silver are leached into the precious liquid in the form of complexes, that is, the leaching of gold and silver is achieved; then the cyanide slag is washed and filtered, and the liquid-to-solid ratio of the washing is 5:1 to wash away the leached gold and silver. After washing, the cyanide slag is dried to obtain iron concentrate.

[0051] For the leaching of gold and silver under ultrasonic conditions, the Golden Cicada agent is used instead of the highly toxic sodium cyanide agent to leach the gold and silver in the alkaline leaching residue. This not only improves the leaching rate of gold and silver, but also, as a new type of environmentally friendly mineral processing agent, the Golden Cicada agent can greatly alleviate the harm caused by toxic agents.

[0052] The calcined sand described in this embodiment is comprehensively recovered by the method described in the present invention, and the recovery data of each metal element are shown in the following table:

[0053]

[0054] Based on the metal element contents in the table above, the gold leaching rate was calculated to be 94.65%, the silver leaching rate was 84.85%, the arsenic removal rate was 95.54%, the sulfur removal rate was 94.61%, the copper leaching rate was 87.65%, and the zinc leaching rate was 88.77%. The resulting high-quality iron ore concentrate contained 63.36% iron, 0.031% arsenic, and 0.18% sulfur. This shows that the method of the present invention can effectively improve the recovery of gold, silver, copper, and zinc in calcined sand and reduce the content of harmful elements arsenic and sulfur in the iron ore concentrate.

[0055] Compared with existing technologies, the gold leaching rate increased from 70% to 94.65%, a 24.65% improvement; the silver leaching rate increased from 30%-40% to 84.85%, a 44.85%-54.85% increase. Copper and zinc were previously not recovered, but now are effectively recovered, with copper leaching rates reaching 87.65% and zinc leaching rates reaching 88.77%, respectively, demonstrating a high comprehensive resource utilization rate. The removal rates of harmful elements arsenic and sulfur reached 95.54% and 94.61%, respectively, demonstrating significant removal rates. The resulting iron concentrate reduced arsenic content from 0.47% to 0.031%, and sulfur content from 1.30% to 0.18%. The iron concentrate grade increased from 58.31% to 63.36%, resulting in a high-quality iron concentrate, addressing the issue of low-grade iron concentrate that made it difficult to sell.

[0056] In summary, the present invention uses a combined process of "roasting-cold extraction-acid leaching-ultrasonic NaOH alkaline leaching-ultrasonic gold cicada leaching" to recover complex and difficult-to-treat multi-metal roasted sand. It first undergoes pretreatment through high-temperature roasting, acid leaching, and ultrasonic alkaline leaching, so that impurities in the gold and silver inclusions and arsenic and sulfur in the symbiotic bodies are preferentially removed under high temperature, strong acid, and strong alkaline conditions. At the same time, the cold extraction treatment destroys the structure of the gold and silver inclusions, forming a loose and porous structure and increasing its contact surface area. Under the cavitation effect of ultrasound, the arsenic and sulfur removal rate can be significantly improved, and the roasted sand structure can be made more dispersed, providing a roasted sand structure that is easier to leach for subsequent gold and silver leaching. At the same time, copper and zinc are preferentially leached during the acid leaching process, which not only achieves copper and zinc recovery, but also reduces the reagent consumption in the gold and silver leaching process.

[0057] The pre-treated roasted sand removes over 94% of arsenic and sulfur and over 85% of copper and zinc, creating a loose, porous structure that is more conducive to gold and silver leaching. Subsequently, discontinuous ultrasonic leaching with a Jinchan reagent effectively increases the leaching rate while producing high-quality iron ore concentrate. Furthermore, the environmentally friendly Jinchan reagent replaces the highly toxic sodium cyanide reagent, making it more environmentally friendly and healthier.

[0058] The present invention is described in detail above through specific and preferred embodiments, but those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A comprehensive recovery method for complex and difficult-to-process multi-metal calcine, characterized in that: The steps include: (1) Secondary roasting to remove arsenic and sulfur: roast the calcined sand in a furnace to further remove harmful impurities such as arsenic and sulfur at high temperature; (2) Cold extraction: The roasted sand at high temperature after calcination is directly placed in cold water for cold extraction. The principle of thermal expansion and contraction is used to make the high-temperature roasted sand extremely shrink and break in cold water, thereby destroying the gold and silver inclusions and forming a loose porous structure in the roasted sand, effectively increasing its contact surface area. After the cold extraction is completed, it is filtered; (3) Acid leaching method for copper and zinc recovery: The roasted sand obtained by cold extraction and filtration is transferred to an acid leaching stirring tank and water is added to prepare a pulp. After the pulp is evenly stirred, sulfuric acid is added and heated for acid leaching to obtain an acid leaching solution and an acid leaching residue. The leached copper, zinc, arsenic and sulfur enter the acid leaching solution, thereby achieving the leaching of copper and zinc and further removal of part of the arsenic and sulfur. The acid leaching residue is then washed and filtered to clean the leached copper, zinc, arsenic and sulfur. After washing, the acid leaching residue is dried. (4) Ultrasonic NaOH alkaline leaching enhanced pretreatment: The dried acid leaching residue is transferred to a leaching stirring tank and water is added to make pulp. After the pulp is evenly stirred, sodium hydroxide is added. The ultrasonic device is started while heating the alkaline leaching. Alkaline leaching liquid and alkaline leaching residue are obtained by ultrasonic leaching. The leached arsenic and sulfur enter the alkaline leaching liquid, thus achieving further removal of arsenic and sulfur. The alkaline leaching residue is then washed and filtered to clean the leached arsenic and sulfur. After washing, the alkaline leaching residue is dried. (5) Intermittent ultrasonic-Jinchan leaching of gold and silver: Add the dried alkaline leaching residue into the leaching stirring tank and add water to make pulp. After the pulp is evenly stirred, add lime to adjust the pH value to 11-12, add Jinchan reagent, and start the ultrasonic device at the same time. During the leaching process of Jinchan reagent, the ultrasonic device is started and stopped intermittently, and precious liquid and cyanide slag are leached. Gold and silver enter the precious liquid in the form of complexes, that is, the leaching of gold and silver is achieved; then the cyanide slag is washed and filtered to clean the leached gold and silver. After washing, the cyanide slag is dried to obtain iron concentrate.

2. A comprehensive recovery method for complex and difficult-to-process multi-metal calcine according to claim 1, characterized in that: In step (1), the calcination temperature is 600° C. and the calcination time is 2 h.

3. A comprehensive recovery method for complex and difficult-to-process multi-metal calcine according to claim 1, characterized in that: The liquid-to-solid ratio of the cold extraction treatment in step (2) is 3:1; stirring is started during the cold extraction treatment, and the stirring speed is 1200 r / min.

4. A comprehensive recovery method for complex and difficult-to-treat multi-metal calcine according to claim 1 or 3, characterized in that: The cold extraction treatment time in step (2) is 2 hours.

5. A comprehensive recovery method for complex and difficult-to-process multi-metal calcine according to claim 1, characterized in that: The liquid-to-solid ratio of the pulping in step (3) is 1.5:1, and the rotation speed of the stirring device is 800 r / min; the liquid-to-solid ratio of the acid leaching residue washing is 5:

1.

6. A comprehensive recovery method for complex and difficult-to-treat multi-metal calcine according to claim 1 or 5, characterized in that: In step (3), the amount of sulfuric acid used is 380 kg / t; the acid leaching temperature is 90° C., and the acid leaching time is 2 h.

7. A comprehensive recovery method for complex and difficult-to-process multi-metal calcine according to claim 1, characterized in that: The liquid-to-solid ratio of the pulping in step (4) is 1.5:1, and the rotation speed of the stirring device is 800 r / min; the liquid-to-solid ratio of the alkali leaching residue washing is 5:

1.

8. A comprehensive recovery method for complex and difficult-to-treat multi-metal calcine according to claim 1 or 7, characterized in that: In step (4), the amount of sodium hydroxide used is 160 kg / t; the alkali leaching temperature is 90° C., the alkali leaching time is 3 h; and the intensity of the ultrasonic device is 200 W.

9. A comprehensive recovery method for complex and difficult-to-process multi-metal calcine according to claim 1, characterized in that: The intensity of the ultrasonic device in step (5) is 200W. The start and stop control of the ultrasonic device is specifically to start when the Jinchan agent is added, shut down after 2 hours of ultrasonic leaching, and start again after 4 hours of leaching, that is, the ultrasonic wave is turned on for 2 hours and stopped for 4 hours, and so on and so forth until the ultrasonic wave is turned on for a total of 6 hours, and then the ultrasonic wave is stopped.

10. A comprehensive recovery method for complex and difficult-to-process multi-metal calcine according to claim 1 or 9, characterized in that: In step (5), the leaching time of the Jinchan agent is 24 hours; the amount of lime used is 6 kg / t; the amount of Jinchan agent used is 1.5 kg / t; and the liquid-solid ratio of the cyanide slag washing is 5:1.

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