Equipment for the comprehensive recovery of silver and iron from complex and difficult-to-process polymetallic tailings

Abstract

This utility model relates to equipment for the comprehensive recovery of silver and iron from complex and difficult-to-process polymetallic tailings. It includes a #1 slurry mixing tank, with a high-gradient magnetic separator connected to its outlet. The concentrate outlet of the high-gradient magnetic separator is connected to a #1 filter press. The filter residue outlet of the #1 filter press is connected to a rotary kiln via a #2 silo and a #2 conveyor belt. The rotary kiln outlet is connected to the #2 slurry mixing tank via a #3 silo and a #3 conveyor belt. The outlet of the #2 slurry mixing tank is connected to a leaching tank, and the outlet of the leaching tank is connected to the #2 filter press. The filter residue outlet of the #2 filter press is connected to the #3 slurry mixing tank via a #4 silo and a #4 conveyor belt. The outlet of the #3 slurry mixing tank is sequentially connected to a weak magnetic roughing separator and a weak magnetic cleaning separator. This utility model effectively achieves efficient recovery of silver and iron from ores with a complex intergrowth structure of "iron as the body, manganese as the shell, and silver as the core," successfully solving the beneficiation and smelting problems of tailings with complex intergrowth structures of silver, iron, and manganese. The entire equipment is rationally designed, and the various devices work synergistically to maximize resource recovery efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of tailings comprehensive recycling technology, specifically relating to a device for the comprehensive recovery of silver and iron from complex and difficult-to-process polymetallic tailings. Background Technology

[0002] For tailings with a complex intergrowth structure composed of silver, iron, and manganese, the main mineral is limonite, with a relatively low copper content. Lead minerals are primarily pyrolusite, and gangue minerals are mainly carbonate minerals such as dolomite and calcite. The ore contains 27.65 g / t of silver, 25.32% of iron, and 2.16% of manganese. The ore particle size is fine, with -0.038 mm accounting for 90%, and silver and iron reaching a distribution rate of 40.55% in the -0.010 mm range. The silver is mainly found within the limonite, filling the clay within the limonite pores. The intergrowth relationship between silver and manganese minerals is very close; manganese oxide forms a dense coating on the fine silver particles and exhibits complex symbiosis with the limonite. This complex intergrowth structure of ore, with "iron as the body, manganese as the shell, and silver as the core," makes it difficult to effectively recover silver and iron using conventional cyanidation and magnetic separation methods. Among them, conventional cyanidation cannot effectively leach silver due to the obstruction of the coating layer, and the silver leaching rate is only 20% to 25%. Although magnetic separation can recover some iron minerals, it is difficult to obtain high-quality iron concentrate, and it cannot effectively recover the coated silver. In the end, a large amount of silver and iron resources are lost in the tailings, resulting in resource waste and environmental pressure. Utility Model Content

[0003] To address the aforementioned problems, this utility model provides equipment for the comprehensive recovery of silver and iron from complex and difficult-to-process polymetallic tailings. The aim is to develop a new technology that can effectively break through iron-manganese inclusions, dissociate and enrich silver, and simultaneously recover iron, thereby achieving efficient recovery of silver and iron resources.

[0004] The specific technical solution is as follows: Equipment for the comprehensive recovery of silver and iron from complex and difficult-to-process polymetallic tailings includes a #1 slurry conditioning tank. A high-gradient magnetic separator is connected to the outlet of the #1 slurry conditioning tank. A #1 filter press is connected to the concentrate outlet of the high-gradient magnetic separator. The filter residue outlet of the #1 filter press is connected to a rotary kiln via a #2 silo and a #2 conveyor belt. The rotary kiln outlet is connected to the #2 slurry conditioning tank via a #3 silo and a #3 conveyor belt. A leaching tank is connected to the outlet of the #2 slurry conditioning tank. The leaching tank outlet is connected to the #2 filter press. The filter residue outlet of the #2 filter press is connected to the #3 slurry conditioning tank via a #4 silo and a #4 conveyor belt. A weak magnetic coarse separator and a weak magnetic fine separator are sequentially connected to the outlet of the #3 slurry conditioning tank.

[0005] Furthermore, preferably, the feed inlet of the No. 1 slurry mixing tank is connected to the discharge outlet of the No. 1 silo via the No. 1 conveyor belt.

[0006] Furthermore, preferably, the high gradient magnetic separator uses a bristle-magnetic rubber composite medium as the magnetic medium.

[0007] Furthermore, preferably, the leaching tank is equipped with a microwave device and a heating device.

[0008] The beneficial effects of this invention are as follows: This invention, through its supporting equipment for a combined process of "composite medium strong magnetic pre-enrichment and waste disposal - catalytic temperature-controlled magnetized roasting - microwave-enhanced sodium thiosulfate leaching of silver - weak magnetic separation for iron recovery," effectively achieves the efficient recovery of silver and iron from ores with a complex intergrowth structure of "iron as the body, manganese as the shell, and silver as the core." It successfully solves the beneficiation and smelting problem of tailings with complex intergrowth structures of silver, iron, and manganese. The entire equipment is rationally designed, and the various components work synergistically to maximize resource recovery efficiency while also considering environmental and economic benefits. Specific technical benefits are as follows: (1) This utility model adopts a high gradient magnetic separator with steel wool-magnetic rubber composite medium, which significantly improves the collection rate of fine silver and iron particles. In particular, the recovery rate of particles with a particle size of less than 10 micrometers can reach more than 80%, breaking through the limitations of traditional magnetic separation process.

[0009] (2) In the roasting stage, this utility model adopts a three-in-one technology of “catalytic low-temperature manganese decomposition + four-stage temperature control to protect silver and prevent sintering + in-situ magnetization to improve quality and reduce consumption”, which realizes the unity of “low-temperature manganese decomposition” and “silver protection magnetization” in iron and manganese tailings resources, greatly reduces the volatilization loss rate of silver, and improves the reduction rate of manganese and the conversion rate of magnetite.

[0010] (3) This invention utilizes the local high temperature and energy focusing characteristics of microwave devices, combined with sodium citrate to synergistically dissociate manganese oxide inclusions, to achieve nanoscale cracks, further release fine silver particles, and significantly improve the silver leaching rate.

[0011] (4) This utility model uses sodium thiosulfate instead of traditional sodium cyanide for silver leaching, which avoids the safety and environmental risks brought by cyanide and reduces the difficulty of harmless treatment of tailings.

[0012] (5) This utility model uses a high gradient magnetic separator for pre-enrichment and a rotary kiln for catalytic temperature-controlled magnetization roasting before leaching, which greatly reduces the amount of leaching and energy consumption and lowers the production cost. Attached Figure Description

[0013] Figure 1 This is an overall structural diagram of the present invention; Figure 2 yes Figure 1 Local magnification Figure 1 ; Figure 3 yes Figure 1 Local magnification Figure 2 ; In the diagram: 1-1# silo, 12-2-1# conveyor belt, 3-1# slurry preparation tank, 4-high gradient magnetic separator, 5-1# filter press, 6-2# silo, 7-2# conveyor belt, 8-rotary kiln, 9-3# silo, 10-3# conveyor belt, 11-2# slurry preparation tank, 12-leaching tank, 13-2# filter press, 14-4# silo, 15-4# conveyor belt, 16-3# slurry preparation tank, 17-weak magnetic coarse separator, 18-weak magnetic fine separator, 19-microwave device, 20-heating device. Detailed Implementation

[0014] To make the technical problems and solutions solved by this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0015] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0016] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Example

[0017] like Figure 1-3As shown in the figure, this embodiment provides equipment for the comprehensive recovery of silver and iron from complex and difficult-to-process polymetallic tailings. It includes a #1 slurry mixing tank 3, whose inlet is connected to the discharge port of a #1 silo 1 via a #1 conveyor belt 2. The discharge port is connected to a high-gradient magnetic separator 4, which uses a steel wool-magnetic rubber composite medium as the magnetic medium. The concentrate outlet of the high-gradient magnetic separator 4 is connected to a #1 filter press 5, whose filter cake outlet is connected to a #2 silo 6 and a #2 conveyor belt 7. Rotary kiln 8 and rotary kiln 6 are connected to slurry preparation tank 11 via silo 3 9 and conveyor belt 3 10. Leaching tank 12 is connected to leaching tank 11 via silo 3 9 and conveyor belt 3 10. Leaching tank 12 is equipped with microwave device 19 and heating device 20. Filter press 13 is connected to filtration press 13 via filter cake outlet. Filtration tank 13 is connected to slurry preparation tank 16 via silo 4 14 and conveyor belt 4 15. Weak magnetic coarse separator 17 and weak magnetic fine separator 18 are connected to slurry preparation tank 16 via slurry preparation tank 3 16 via silo 4 14 and conveyor belt 4 15. Weak magnetic coarse separator 17 and weak magnetic fine separator 18 are connected to slurry preparation tank 16 via slurry preparation tank 16.

[0018] It should be noted that the above-mentioned equipment are all existing equipment, and this application only relates to the application of these existing equipment, and does not involve any improvement of their structure.

[0019] This invention primarily addresses the composition and occurrence characteristics of polymetallic tailings. Before leaching, a composite-media high-intensity magnetic separation device is used to pre-enrich and discard the tailings, preventing waste rock from directly entering the leaching stage and causing problems such as large processing volumes and high costs. Next, a catalytic temperature-controlled magnetized roasting device is employed. By precisely controlling the roasting temperature, under the catalytic action of CaCl2, CO selectively reduces manganese oxide (MnO2), effectively dissociating iron and manganese inclusions in the iron concentrate and simultaneously converting limonite into magnetite, laying a solid foundation for subsequent silver leaching and iron recovery. Following this, the leaching stage begins, incorporating sodium citrate deep dissociation and microwave-enhanced nanoscale inclusion rupture technology to further release fine silver particles. Sodium thiosulfate is then used for non-toxic leaching, significantly improving the silver leaching rate. Finally, two stages of weak magnetic separation are used to fully recover the converted magnetite, ultimately achieving efficient recovery of silver and iron from polymetallic tailings.

[0020] The specific working principle of the above system for recovering complex and difficult-to-process polymetallic tailings is as follows: (1) Composite medium strong magnetic pre-enrichment and waste disposal: The polymetallic tailings fall from silo 1# and are conveyed to slurry tank 3# via conveyor belt 2#. Water is added to adjust the slurry to a concentration of 25%, and then it is transferred to high gradient strong magnetic separator 4 for magnetic separation to obtain iron concentrate and strong magnetic separation tailings. In the magnetic separation process, a high gradient strong magnetic separator with steel wool-magnetic rubber composite medium is used. Utilizing its wedge-shaped protruding tip effect, vortex capture and low-speed barrier, and surface particle effect enhancement, it can achieve efficient capture of fine silver-iron particles, thereby significantly improving the recovery rate of fine silver-iron particles with a particle size of less than 10 μm.

[0021] The magnetic medium used in this high-gradient magnetic separator is significantly superior to that of conventional stainless steel wool media. When using conventional stainless steel wool media, the magnetic field gradient decays rapidly, and the smooth surface results in weak van der Waals adsorption forces. For fine silver-containing iron particles with a particle size of less than 10 μm, the recovery rate is typically less than 20%.

[0022] (2) Catalytic temperature-controlled magnetization roasting This roasting process, through precise control of roasting temperature changes, uses CaCl2 as a catalyst and operates in a CO+N2 mixed gas environment. It employs a three-pronged approach: catalytic low-temperature manganese decomposition, fourth-stage temperature control for silver protection and anti-sintering, and in-situ magnetization for quality improvement and energy saving. This achieves the unified process of "low-temperature manganese decomposition" and "silver protection magnetization" in iron-manganese tailings resources, as detailed below: The first stage, preheating and dehydration: The iron concentrate slurry obtained from magnetic separation is transferred to filter press 5 (No. 1) for filtration. The iron concentrate obtained from the filtration chamber is transferred to silo 6 (No. 2). At this time, CaCl2 solution is added to the iron concentrate. After mixing, it is transferred to rotary kiln 8 (No. 2 conveyor belt) for roasting. The temperature is raised to 500℃ and kept constant for 20 minutes to remove adsorbed water and crystal water of limonite from the iron concentrate, avoid water vapor interference with the subsequent reducing atmosphere, and melt CaCl2 at the same time. The second stage, catalytic reduction of manganese oxides: CO + N2 mixed gas is introduced into rotary kiln 8, the temperature is raised to 600℃ and kept constant for 120 min. Under the catalytic action of CaCl2, CO selectively reduces manganese oxide. At this time, due to the mechanical stress generated by volume shrinkage, the manganese inclusions break and release silver particles. The third stage, magnetization of limonite and enhancement of silver dissociation: The temperature was raised to 700℃ and held for 60 min. Under the action of CO, Fe2O3 was converted into strongly magnetic Fe3O4. At the same time, the catalytic effect of CaCl2 was enhanced at high temperature, which further destroyed the residual manganese inclusions and limonite structure, allowing silver to be more fully exposed. The fourth stage is cooling: stop heating and close the CO inlet valve, adjust the N2 inlet valve to reduce the flow rate, and allow the calcined sand to cool to a safe temperature under the protection of an inert atmosphere before being taken out of the furnace. The inert atmosphere can prevent hot magnetite Fe3O4 and low-valence manganese from being oxidized by air, ensuring the quality of the calcined sand and the smooth progress of subsequent processes. (3) Microwave-enhanced sodium thiosulfate leaching for silver recovery: The calcined sand transferred to silo 3#9 is conveyed to tank 2#11 via conveyor belt 10, and water is added to adjust the slurry to a concentration of 30%, and then it is transferred to leaching tank 12. Sodium carbonate is added to leaching tank 12 to adjust the pH of the solution to 9.5, and then sodium citrate and sodium thiosulfate are added. After stirring evenly, heating device 20 and microwave device 19 are started, and the temperature is raised to 50℃ and kept constant. The microwave is turned on for 2 hours and then turned off. After leaching for 6 hours, the solution is filtered by filter press 2#13 to separate the silver-containing precious solution and leaching tailings. In this process, sodium thiosulfate (non-toxic) acts as a leaching agent, reacting with silver to form a soluble silver thiosulfate complex, thus leaching the silver. Sodium carbonate regulates and stabilizes the alkaline environment of the solution, inhibiting the decomposition of thiosulfate and ensuring that sodium thiosulfate continues to play its role during the leaching process. Sodium citrate reacts with manganese oxide to deeply dissociate manganese oxide inclusions, releasing the encapsulated silver particles, while simultaneously complexing and shielding Fe³⁺ to prevent Fe(OH)₃ colloids from encapsulating silver. At the same time, microwave technology utilizes the absorption and amplification effect of magnetite in roasted sand to focus microwave energy on manganese oxide inclusions, generating localized high temperatures that cause lattice rupture and the formation of nanoscale cracks, further releasing fine silver particles and thus improving the silver leaching rate.

[0023] (4) Weak magnetic separation to recover iron: The leaching tailings that fall into the No. 4 silo 14 are transported to the No. 3 slurry tank 16 via the No. 4 conveyor belt 15. After adding water to adjust the slurry to a concentration of 25%, it is transferred to the weak magnetic roughing separator 17 for roughing to obtain weak magnetic roughing tailings and roughing iron concentrate. The roughing iron concentrate is then transferred to the weak magnetic cleaning separator 18 for cleaning to finally obtain magnetite concentrate and weak magnetic tailings.

[0024] This complex and difficult-to-process polymetallic tailings consists mainly of limonite, with a relatively low copper content. Lead minerals are primarily pyrolusite, and gangue minerals are mainly carbonates such as dolomite and calcite. It contains 27.65 g / t of silver, 25.32% of iron, and 2.16% of manganese. The ore has a fine particle size, with 90% being -0.038 mm, and silver and iron reaching a distribution rate of 40.55% in the -0.010 mm range. The silver is mainly found within the limonite, filling the clay within the pores of the limonite. The silver and manganese minerals are closely intergrown, with manganese oxide forming a dense coating on the fine silver particles and exhibiting complex symbiosis with the limonite.

[0025] The comprehensive recycling using the equipment described in this utility model is implemented as follows: (1) Composite medium strong magnetic pre-enrichment and waste disposal: The polymetallic tailings fall from silo 1# and are conveyed to slurry tank 3# via conveyor belt 2#. Water is added to adjust the slurry to a concentration of 25%, and then the slurry is transferred to a high gradient strong magnetic separator 4 for magnetic separation. The magnetic field strength is 1.5T, and iron concentrate and strong magnetic separation tailings are obtained. Among them, the recovery rate of fine iron concentrate (particle size less than 10um) reaches 84.45%.

[0026] (2) Catalytic temperature-controlled magnetization roasting Using CaCl2 as a catalyst, in a CO+N2 mixed gas environment, a three-in-one technology of "catalytic low-temperature manganese decomposition + fourth-stage temperature-controlled silver protection and anti-sintering + in-situ magnetization for quality improvement and energy saving" is adopted to achieve the unification of "low-temperature manganese decomposition" and "silver protection magnetization" in iron-manganese tailings resources, as detailed below: The first stage, preheating and dehydration: The iron concentrate slurry obtained from magnetic separation is transferred to filter press 5 (No. 1) for filtration. The iron concentrate obtained from the filtration chamber is transferred to silo 6 (No. 2). At this time, CaCl2 solution (consumption of 10 kg / t) is added to the iron concentrate. After mixing, it is transferred to rotary kiln 8 via conveyor belt 7 (No. 2) for roasting. The temperature is raised to 500℃ and kept constant for 20 minutes to remove adsorbed water and crystal water of limonite from the iron concentrate, avoid water vapor interference with the subsequent reducing atmosphere, and melt CaCl2 at the same time. The second stage, catalytic reduction of manganese oxide: a mixture of CO (consumption of 40 Nm³ / t) and N2 (consumption of 160 Nm³ / t) gas is introduced into rotary kiln 8, the temperature is raised to 600℃ and held for 120 min. Under the catalytic action of CaCl2, CO selectively reduces manganese oxide. At this time, due to the mechanical stress generated by volume shrinkage, the manganese inclusions break and release silver particles. The third stage, magnetization of limonite and enhancement of silver dissociation: The temperature was raised to 700℃ and held for 60 min. Under the action of CO, Fe2O3 was converted into strongly magnetic Fe3O4. At the same time, the catalytic effect of CaCl2 was enhanced at high temperature, which further destroyed the residual manganese inclusions and limonite structure, allowing silver to be more fully exposed. The fourth stage is cooling: stop heating and close the CO inlet valve, adjust the N2 inlet valve to reduce its flow rate (N2 consumption is 40 Nm³ / t), and allow the roasted sand to cool to a safe temperature under the protection of an inert atmosphere before being taken out of the furnace. The inert atmosphere can prevent hot magnetite Fe3O4 and low-valence manganese from being oxidized by air, ensuring the quality of roasted sand and the smooth progress of subsequent processes. After the above four stages of processing, the volatilization loss rate of silver was reduced from the traditional 10% to 15% to less than 1%, the reduction rate of manganese was 94.54%, and the conversion rate of magnetite was 96.65%.

[0027] (3) Microwave-enhanced sodium thiosulfate leaching for silver recovery: The calcined sand transferred to silo 9 is conveyed to tank 2 11 via conveyor belt 10. Water is added to adjust the slurry to a concentration of 30%, and then it is transferred to leaching tank 12. Sodium carbonate (consumption 1.6 kg / t) is added to leaching tank 12 to adjust the pH of the solution to 9.5. Then sodium citrate (consumption 2.1 kg / t) and sodium thiosulfate (consumption 4 kg / t) are added. After stirring evenly, heating device 20 and microwave device 19 (frequency 2.45 GHz, power 2 kW) are started. The temperature is raised to 50°C and kept constant. The microwave is turned on for 2 hours and then turned off. After leaching for 6 hours, the solution is filtered by filter press 13 to separate the silver-containing precious solution and leaching tailings. The silver leaching rate is 90.55%.

[0028] (4) Weak magnetic separation to recover iron: After adjusting the leaching tailings to a concentration of 25%, the slurry is transferred to a weak magnetic rougher for roughing. The magnetic field strength is 300mT, resulting in weak magnetic tailings and crude iron concentrate. The crude iron concentrate is then transferred to a weak magnetic cleaner for further cleaning. The magnetic field strength is 180mT, ultimately yielding magnetite concentrate and weak magnetic tailings.

[0029] After the above treatment, the silver recovery rate of this complex and difficult-to-process polymetallic tailings reached 84.44%, and a high-quality iron concentrate with a yield of 34.96%, an iron grade of 62.05%, and a recovery rate of 86.74% was obtained. This breakthrough in the beneficiation and smelting challenges of the complex silver-iron-manganese occurrence state has enabled the efficient recovery of silver and iron resources.

[0030] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications or equivalent substitutions made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An equipment for comprehensive recovery of silver and iron from complex refractory polymetallic tailings, characterized in that it comprises: The system includes a 1# slurry conditioning tank (3), the outlet of which is connected to a high gradient magnetic separator (4), the concentrate outlet of which is connected to a 1# filter press (5), the filter residue outlet of which is connected to a rotary kiln (8) via a 2# silo (6) and a 2# conveyor belt (7), the outlet of which is connected to a 2# slurry conditioning tank (11) via a 3# silo (9) and a 3# conveyor belt (10), the outlet of which is connected to a leaching tank (12), the outlet of which is connected to a 2# filter press (13), the filter residue outlet of which is connected to a 3# slurry conditioning tank (16) via a 4# silo (14) and a 4# conveyor belt (15), and the outlet of which is connected to a weak magnetic coarse separator (17) and a weak magnetic fine separator (18) in sequence.

2. The equipment for comprehensive recovery of silver and iron from complex refractory polymetallic tailings according to claim 1, characterized in that: The feed inlet of the No. 1 slurry tank (3) is connected to the discharge outlet of the No. 1 silo (1) via the No. 1 conveyor belt (2).

3. The equipment for comprehensive recovery of silver and iron from complex refractory polymetallic tailings according to claim 1, characterized in that it comprises: The high gradient magnetic separator (4) uses steel wool-magnetic rubber composite medium as the magnetic medium.

4. The equipment for comprehensive recovery of silver and iron from complex refractory polymetallic tailings according to any one of claims 1-3, characterized in that: The leaching tank (12) is equipped with a microwave device (19) and a heating device (20).

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