Comprehensive recovery method for complex and difficult-to-treat polymetallic calcine

Abstract

The invention relates to a comprehensive recovery method for complex and difficult-to-treat polymetallic calcine. The comprehensive recovery method comprises the following steps: (1) secondary roasting to remove arsenic and sulfur; (2) cold extraction treatment; (3) recovering copper and zinc by an acid leaching method; (4) performing ultrasonic NaOH alkaline leaching enhanced pretreatment; and (5) intermittent ultrasonic-golden cicada leaching of gold and silver. According to the combined process of roasting, cold extraction, acid leaching, ultrasonic NaOH alkaline leaching and ultrasonic golden cicada leaching, provided by the invention, for complex and difficult-to-treat multi-metal calcine, high-temperature roasting, an acid leaching method and an ultrasonic alkaline leaching method are firstly adopted for pretreatment, so that impurities in gold and silver inclusions and arsenic and sulfur of symbiotic intergrowth bodies react under the conditions of high temperature, strong acid and strong alkali to be preferentially removed; and meanwhile, a gold and silver inclusion structure is destroyed through cold extraction treatment, a loose porous structure is formed, arsenic and sulfur can be removed to the maximum extent under the cavitation effect of ultrasonic waves, then gold and silver are efficiently leached through intermittent ultrasonic waves and a golden cicada agent, and valuable elements such as gold, silver, copper, zinc and iron with the high leaching rate are obtained.

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] There is a complex and difficult to process multi-metal roasted sand, which 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. Most of the materials in the roasted sand are ferric oxide, with a small amount of quartz, gypsum, potassium feldspar, biotite, chlorite, etc. The gold minerals in the roasted sand are natural gold and silver-gold ores, and the silver minerals are mainly silver ores, with a small amount of sulfide-copper-silver ores and trace amounts of silver-gold ores. The embedded particle size of gold minerals is more concentrated below 20µm, of which gold minerals less than 1µm account for as high as 29.25%; the embedded particle size of silver and arsenic is finer, and the fine particle size distribution below 8um is higher, with a distribution rate of 54.09% and 60.30% respectively, and about 50% of the gold and silver minerals are wrapped in ferric oxide and gangue minerals.

[0003] For this type of multi-metal roasted sand, the roasted sand "water washing-cyanide leaching" process is currently mainly used to recover the gold and silver in it. Generally, the gold leaching rate is 70.00%, the silver leaching rate is 30% to 40%, and the cyanide tailings are mainly iron concentrate (iron grade is 58.31%, arsenic grade is 0.47%, and sulfur grade is 1.30%). It can be seen that the main problems in the implementation of this recovery process are as follows: (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 leaching rates of gold and silver. The gold leaching rate is only 70.00% and the silver leaching rate is only 30% to 40%.

[0004] (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 3kg / t), which increased the amount of reagents used.

[0005] (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.

[0006] (4) The use of highly toxic sodium cyanide as a reagent for leaching gold and silver poses a great threat to operators and the environment, and also creates great pressure on reagent transportation, storage, and environmental protection during the production process. Summary of the invention

[0007] In view of 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 arsenic and sulfur, and finally obtain high-quality iron ore concentrate.

[0008] The specific technical solution is: a comprehensive recovery method for complex and difficult to handle multi-metal roasted sand, comprising the following steps: (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 temperatures; (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 specific surface area. After the cold extraction is completed, filtering is performed; (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 make 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 removing 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, and the ultrasonic device is started while heating the alkaline leaching. Ultrasonic leaching is performed to obtain alkaline leaching solution and alkaline leaching residue, in which the leached arsenic and sulfur enter the alkaline leaching solution, that is, the arsenic and sulfur are further removed; then the alkaline leaching residue is washed and filtered to clean the leached arsenic and sulfur, and the alkaline leaching residue is dried after washing; 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 the subsequent leaching of gold and silver.

[0009] (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 stirred evenly, 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 to obtain precious liquid and cyanide slag. Gold and silver enter the precious liquid in the form of complexes, thus achieving the leaching of gold and silver. 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.

[0010] 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 can not only increase 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.

[0011] Furthermore, in step (1), the calcination temperature is 600° C., the calcination time is 2 h, and the furnace door is slightly opened during calcination to ensure that air can enter.

[0012] Furthermore, the liquid-to-solid ratio of the cold extraction treatment in step (2) is 3:1.

[0013] Furthermore, in step (2), stirring is started during the cold extraction process, and the stirring speed is 1200 r / min.

[0014] Furthermore, the cold extraction treatment time in step (2) is 2 hours.

[0015] 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.

[0016] Furthermore, the amount of sulfuric acid used in step (3) is 380 kg / t.

[0017] Furthermore, in step (3), the acid leaching temperature is 90° C. and the acid leaching time is 2 h.

[0018] Furthermore, in step (3), the liquid-to-solid ratio of the acid leaching residue washing is 5:1.

[0019] 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.

[0020] Furthermore, the amount of sodium hydroxide used in step (4) is 160 kg / t.

[0021] Furthermore, in step (4), the alkali leaching temperature is 90° C. and the alkali leaching time is 3 h.

[0022] Furthermore, in step (4), the liquid-to-solid ratio of the alkaline leaching residue washing is 5:1.

[0023] Furthermore, the intensity of the ultrasonic device in step (4) is 200W.

[0024] 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.

[0025] Furthermore, the intensity of the ultrasonic device in step (5) is 200W.

[0026] Furthermore, in step (5), the leaching time of the golden cicada agent is 24 hours.

[0027] Furthermore, the amount of lime used in step (5) is 6 kg / t.

[0028] Furthermore, in step (5), the dosage of the golden cicada agent is 1.5 kg / t.

[0029] Furthermore, in step (5), the liquid-to-solid ratio of the cyanide slag washing is 5:1.

[0030] Beneficial effects of the present invention: (1) The combined process of "roasting-cold extraction-acid leaching-ultrasonic NaOH alkali leaching-ultrasonic gold cicada leaching" provided by the present invention can comprehensively recover the valuable elements gold, silver, copper, zinc and iron in 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 rate and economic benefits are significantly improved.

[0031] (2) The present invention pre-treats complex and difficult-to-treat 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 intergrowth are preferentially removed under high temperature, strong acid and strong alkali conditions. At the same time, the structure of the gold and silver inclusions is destroyed by cold extraction, so that a loose porous structure is formed, and its contact specific surface area is increased. Under the cavitation effect of ultrasonic waves, 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.

[0032] (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.

[0033] (4) The pre-treated roasted sand is then leached with intermittent ultrasonic wave and Golden Cicada reagent to effectively improve the leaching rate of gold and silver, while obtaining 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

[0034] Figure 1 The present invention is a flow chart of a comprehensive recovery method for complex and difficult-to-treat multi-metal roasted sand. DETAILED DESCRIPTION

[0035] 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 in conjunction with 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 used to limit the present invention.

[0036] Roasted sand ore: a complex and difficult to process multi-metal roasted sand, 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. Most of the materials in the roasted sand are ferric oxide, with a small amount of quartz, gypsum, potassium feldspar, biotite, chlorite, etc. The gold minerals in the roasted sand are natural gold and silver-gold ores, and the silver minerals are mainly silver ores, with a small amount of sulfide-copper-silver ores and trace amounts of silver-gold ores. The embedded particle size of gold minerals is more concentrated below 20µm, of which gold minerals less than 1µm account for as high as 29.25%; the embedded particle size of silver and arsenic is finer, and is distributed more in the fine particle size below 8µm, with a distribution rate of 54.09% and 60.30% respectively, and about 50% of the gold and silver minerals are encapsulated in ferric oxide and gangue minerals.

[0037] Through the elemental analysis of the roasted sand, it is known that the metals that need to be recovered in the above 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 low leaching rates 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 the combined process of "roasting-cold extraction-acid leaching-ultrasonic NaOH alkali leaching-ultrasonic golden cicada leaching" for comprehensive recovery of the above roasted sand, and the specific implementation steps are as follows: (1) Secondary roasting to remove arsenic and sulfur: Set the roasting temperature of the muffle furnace to 600°C, start the muffle furnace to heat up, and when the temperature reaches 600°C, put the weighed roasted sand into the muffle furnace for roasting, while ensuring 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 harmful impurities such as arsenic and sulfur, and prepare for the subsequent roasted sand cold extraction.

[0038] (2) Cold extraction: The roasted sand at high temperature after calcination is directly placed in cold water for cold extraction, wherein the liquid-to-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; (3) Acid leaching method for copper and zinc recovery: The roasted sand obtained by cold extraction filtration is transferred to an 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°C, the timing is started, and the slurry temperature is maintained at 90°C. 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 an acid leaching solution and an acid leaching residue, in which 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, and 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; (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 the ultrasonic device (ultrasonic intensity is 200W) are started. When the temperature of the slurry rises to 90℃, the timing is started, and the slurry temperature is maintained at 90℃. After 3h 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 the alkali leaching solution and alkali leaching residue, in which 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. The leached arsenic and sulfur are washed clean, and the alkali leaching residue is dried after washing; 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 the subsequent leaching of gold and silver.

[0039] (5) Intermittent ultrasonic-Jinchan leaching: Add the dried alkali leaching residue to the leaching stirring tank and add water to make pulp. When making pulp, add the corresponding amount of water at a 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), start timing, turn off the ultrasonic wave after 2h of ultrasonic leaching, and start the ultrasonic wave again after 4h of leaching, that is, turn on for 2h and stop for 4h, and repeat this process until the ultrasonic wave is turned on for 6h. Stop stirring when the Jinchan agent has been leached for 24h, and the leaching is finished. After leaching is completed, the slurry is taken out and filtered to obtain precious liquid and cyanide slag, wherein gold and silver are leached into the precious liquid in the form of a complex, 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, and the leached gold and silver are washed clean. After washing, the cyanide slag is dried to obtain iron concentrate.

[0040] 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 can not only increase 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.

[0041] The roasted 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 specifically shown in the following table:

[0042] According to the content of metal elements in the above table, the gold leaching rate is 94.65%, the silver leaching rate is 84.85%, the arsenic removal rate is 95.54%, the sulfur removal rate is 94.61%, the copper leaching rate is 87.65%, and the zinc leaching rate is 88.77%, and the obtained iron concentrate contains 63.36% iron, 0.031% arsenic, and 0.18% sulfur. High-quality iron concentrate. It can be seen that the method of the present invention can effectively improve the recovery of gold, silver, copper, and zinc in roasted sand and reduce the content of harmful elements arsenic and sulfur in iron concentrate.

[0043] Compared with the existing technology, the gold leaching rate increased from 70% to 94.65%, an increase of 24.65%; the silver leaching rate increased from 30% to 40% to 84.85%, an increase of 44.85% to 54.85%, and the silver leaching rate increased significantly. Copper and zinc were not recovered before, and the copper leaching rate reached 87.65% and the zinc leaching rate reached 88.77%, and the comprehensive resource utilization rate was high. The removal rates of harmful elements arsenic and sulfur reached 95.54% and 94.61% respectively, and the removal rate effect was significant. The arsenic content in the obtained iron concentrate was reduced from 0.47% to 0.031%, and the sulfur content was reduced from 1.30% to 0.18%. The grade of the iron concentrate increased from 58.31% to 63.36%, which is a high-quality iron concentrate, solving the problem of low-grade iron concentrate and difficult sales.

[0044] In general, the present invention adopts a combined process of "roasting-cold extraction-acid leaching-ultrasonic NaOH alkaline leaching-ultrasonic cicada leaching" to recover complex and difficult-to-treat multi-metal roasted sand. It is first pre-treated 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 of the symbiotic bodies are preferentially removed under high temperature, strong acid and strong alkali conditions. At the same time, the structure of the gold and silver inclusions is destroyed by cold extraction treatment to form a loose porous structure, increase its contact specific surface area, and under the cavitation effect of ultrasonic waves, 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. At the same time, copper and zinc are preferentially leached during the acid leaching process, which can achieve copper and zinc recovery while reducing the consumption of reagents in the gold and silver leaching process.

[0045] The pre-treated roasted sand removes more than 94% of arsenic and sulfur and more than 85% of copper and zinc, and the resulting loose porous structure is more conducive to the leaching of gold and silver. Subsequently, intermittent ultrasonic waves and Jinchan reagents are used to leach gold and silver, which can effectively increase the leaching rate of gold and silver, and obtain high-quality iron concentrate. In addition, the environmentally friendly Jinchan reagent replaces the highly toxic sodium cyanide reagent, which is more environmentally friendly and healthy.

[0046] 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, and any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A comprehensive recovery method for complex and difficult to process multi-metal roasted sand, 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 temperatures; (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 specific surface area. After the cold extraction is completed, filtering is performed; (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 make 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 removing 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, and the ultrasonic device is started while heating the alkaline leaching. Ultrasonic leaching is performed to obtain alkaline leaching solution and alkaline leaching residue, in which the leached arsenic and sulfur enter the alkaline leaching solution, that is, the arsenic and sulfur are further removed; then the alkaline leaching residue is washed and filtered to clean the leached arsenic and sulfur, and the alkaline leaching residue is dried after washing; (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 slurry is stirred evenly, 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 to obtain precious liquid and cyanide slag. Gold and silver enter the precious liquid in the form of complexes, thus achieving the leaching of gold and silver. 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. The comprehensive recovery method of complex and difficult to process multi-metal roasted sand according to claim 1, characterized in that: In step (1), the calcination temperature is 600° C. and the calcination time is 2 h.

3. The comprehensive recovery method of complex and difficult to process multi-metal roasted sand 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 1200r / min.

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

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

1.

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

1.

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

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