A method for recycling complex zinc oxide ore with multiple zinc occurrence states

Abstract

The present invention relates to a method for recycling complex zinc oxide ores with multiple zinc occurrence states, comprising: (1) grinding; (2) recovering encapsulated zinc oxide using a pulsating high-gradient high-intensity magnetic separator to obtain encapsulated or combined zinc oxide concentrate I and magnetic separation tailings; (3) flotation to recover free zinc oxide. Sodium hexametaphosphate and flotation reagents are respectively added for flotation in a flotation system to obtain zinc oxide concentrate II and tailings; (4) the zinc oxide concentrate II obtained in step (3) is calcined at a low temperature to obtain zinc oxide calcined slag; (5) the zinc oxide concentrate I obtained after completing step (2) and the zinc oxide calcined slag of the zinc oxide concentrate II obtained in step (4) are subjected to acid leaching and purification to obtain zinc-containing acid leaching solution and acid leaching residue. The zinc-containing acid leaching solution enters an electrowinning system for treatment to obtain high-quality zinc metal. The present invention can effectively solve the problem of processing and utilization of complex refractory zinc ore resources with multiple zinc occurrence states.

Description

Technical Field

[0001] The invention belongs to the technical field of ore dressing, and in particular relates to a method for recycling complex zinc oxide ore in multiple zinc occurrence states. Background Art

[0002] With the continuous consumption of zinc sulfide ore resources, the development and utilization of zinc oxide ores has become increasingly important, especially for a large number of complex zinc oxide ores, which have the characteristics of low grade, high oxidation rate and bonding rate, fine embedded particle size and complex mineral composition; but due to the complex nature of the ore, it has not been reasonably and effectively developed and utilized, and it has posed a serious threat to environmental protection and safety, and to some extent, it has also increased the difficulty of environmental governance. For a long time, the development and comprehensive recycling of such slag resources has always been highly concerned by people from all walks of life in the industry, and a lot of effort has been devoted to it. Through a lot of research work, it is found that the treatment methods of this type of zinc ore are mainly divided into two types: flotation method and chemical method. Flotation method mainly treats easy-to-select zinc ores, such as smithsonite, etc., but for the treatment of such complex zinc oxide ores, due to the large differences in the physicochemical properties of each zinc-containing phase, this method has low zinc recovery rate, large consumption of flotation reagents and other shortcomings, and cannot achieve the ideal effect. Chemical methods include acid leaching-extraction method and ammonia leaching-evaporation ammonia crystallization method. The acid leaching-extraction method uses sulfuric acid to dissolve zinc oxide, then adds an extractant to enrich zinc in the organic phase, then returns the extraction into the aqueous solution, and then electrolytically deposits. However, due to the high content of acid-soluble substances in low-grade zinc oxide ores, a large amount of sulfuric acid is required, and its production cost is high. In addition, a large amount of acidic waste residue is produced, and there is also an environmental pollution problem, which is difficult for society or enterprises to accept; the ammonia leaching-evaporation ammonia crystallization method uses ammonia-carbon ammonia combined leaching to produce zinc amine complexes, and then purifies, evaporates, dries and calcined to produce zinc oxide products, but this method has not been used for the treatment of low-grade zinc oxide ores, because the original ore contains low zinc, the leaching solution contains low zinc concentration, the leaching agent consumption is large, the cost is high, and the enterprise cannot accept it. In short, so far, the treatment of this type of ore is still one of the most challenging topics in this research field. In order to effectively recycle complex zinc oxide ores with various zinc occurrence states, while overcoming the shortcomings of existing traditional methods, it has become a technical problem that needs to be solved in this industry. Based on this, the present invention provides a method for recycling complex zinc oxide ores with various zinc occurrence states. Summary of the invention

[0003] In view of the above-mentioned problems, the present invention has wide applicability to raw materials, simple operation, low equipment requirements, and is environmentally friendly, and can effectively solve the difficult problem of processing and utilizing complex and difficult-to-treat zinc ore resources in various zinc occurrence states.

[0004] Specific technical solution: A method for recycling complex zinc oxide ores with multiple zinc occurrence states, the specific steps are as follows:

[0005] (1) Crush and grind the complex zinc oxide ore to a particle size where -0.074 mm accounts for 75% - 80%;

[0006] (2) Recover the encapsulated zinc oxide by pulsating high-gradient magnetic separation. After adjusting the pulp of the ore in step (1), feed it into a pulsating high-gradient magnetic separator to recover smithsonite and zinc ferrite spinel, obtaining zinc oxide concentrate Ⅰ containing encapsulated or combined zinc oxide and magnetic separation tailings; during this process, the magnetic separation concentration is 20% - 25%, the diameter of the magnetic medium is 1.5 mm - 3 mm, and the background magnetic induction intensity is 1.3 T - 1.4 T;

[0007] (3) Recover the free zinc oxide by flotation. Add sodium hexametaphosphate to the magnetic separation tailings obtained in step (2) for pulp adjustment, then add flotation reagents for pulp adjustment, and then transport it to the flotation system for flotation of free zinc oxide ore, obtaining zinc oxide concentrate Ⅱ and tailings;

[0008] (4) Roast zinc oxide concentrate Ⅱ by flotation. Transport the zinc oxide concentrate Ⅱ obtained in step (3) to a rotary kiln for low-temperature roasting, obtaining zinc oxide roasted slag and flue gas, and the flue gas goes to the flue gas treatment pond;

[0009] Acid leaching purification - electrowinning. The zinc oxide concentrate Ⅰ containing encapsulated or combined zinc obtained in step (2) and the zinc oxide roasted slag of zinc oxide concentrate Ⅱ obtained in step (4) are respectively fed into the acid leaching purification system for treatment, obtaining zinc-containing acid leaching solution and acid leaching slag. The zinc-containing acid leaching solution enters the electrowinning system for treatment to obtain high-quality zinc metal.

[0010] Further, in step (3), the flotation system includes two rough selections, one roughing, and two scavengings; the dosage of sodium sulfide is 2500 g / t for roughing, 1000 g / t for the first scavenging, and 500 g / t for the second scavenging; the dosage of octadecylamine acetate is 150 g / t for roughing, 80 g / t for the first scavenging, and 40 g / t for the second scavenging; the dosage of kerosene is 100 g / t for roughing, 50 g / t for the first scavenging, and 25 g / t for the second scavenging; the dosage of No. 2 oil is 50 g / t for roughing, 30 g / t for the first scavenging, and 20 g / t for the second scavenging; the dosage of the dispersant sodium hexametaphosphate for roughing is 150 g / t; the roughing flotation concentration is 20% - 22%.

[0011] Further, in step (4), for roasting zinc oxide concentrate Ⅱ by flotation, transport the zinc oxide concentrate Ⅱ obtained after completing the above step (3) to a rotary kiln for low-temperature roasting, and the roasting temperature is 400 °C - 600 °C.

[0012] Furthermore, in step (5), for the acid leaching of the encapsulated or combined zinc oxide concentrate I, sulfuric acid with an initial concentration of 2 mol / l is used, and the molar ratio of sulfuric acid to iron and zinc is 1.2:1. The leaching temperature is 75°C - 80°C, and the leaching time is 3 - 4 hours. For purification, basic zinc carbonate or the calcined slag of zinc oxide concentrate II is slowly adjusted to pH = 5.4; for the acid leaching and purification of the calcined slag of the flotation zinc oxide concentrate II, the initial pH value is 2.0 - 2.5, which is slowly adjusted to pH = 5.4. The leaching temperature is 75°C - 80°C, and the leaching time is 2 - 3 hours.

[0013] The present invention provides a method for recycling complex zinc oxide ores with multiple zinc occurrence states. It belongs to the field of mineral processing. The technical problem to be solved is that for zinc oxide ores with low grade, high oxidation rate and combination rate, fine dissemination size, and complex mineral composition, a method is adopted which includes using pulsating high-gradient high-intensity magnetic separation to recover the encapsulated zinc oxide minerals (smithsonite and zinc ferrite spinel) in the ore, and flotation to recover the free zinc oxide minerals (zincite and hemimorphite), then subjecting the obtained flotation zinc oxide concentrate to low-temperature roasting, and then respectively carrying out a zinc recovery process of acid leaching purification - electrowinning on the magnetic separation concentrate and the calcined slag, so as to improve the zinc ore dressing effect, reduce the cost of flotation reagents, improve the economic benefits of ore dressing, and achieve the purpose of efficiently comprehensively utilizing resources and reducing environmental pollution. This method has a wide applicability to raw materials, is simple to operate, has low equipment requirements, and is environmentally friendly, effectively solving the technical problems in the processing and utilization of such complex refractory zinc ore resources with multiple zinc occurrence states.

[0014] The technical problem to be solved is that for zinc oxide ores with low grade, high oxidation rate and combination rate, fine dissemination size, and complex mineral composition, a method is adopted which includes using pulsating high-gradient high-intensity magnetic separation to recover the encapsulated zinc oxide minerals (smithsonite and zinc ferrite spinel) in the ore, and flotation to recover the free zinc oxide minerals (zincite and hemimorphite), then roasting the obtained flotation zinc oxide concentrate, and then respectively carrying out a zinc recovery process of acid leaching purification - electrowinning on the magnetic separation concentrate and the calcined slag, so as to improve the zinc ore dressing effect, reduce the cost of flotation reagents, improve the economic benefits of ore dressing, and achieve the purpose of efficiently comprehensively utilizing resources and reducing environmental pollution.

[0015] Advantages and positive effects compared with the existing method

[0016] (1) According to the characteristics of zinc phase, zinc-containing minerals are classified and efficiently separated, greatly improving the zinc ore dressing recovery rate;

[0017] (2) By ingeniously using a pulsating high-gradient high-intensity magnetic separator to pre-magnetically separate magnetic zinc-containing minerals in advance, it not only realizes the ore dressing principle of "recovering as early as possible", but also reduces the fine-grained limonite entering the flotation system, improves the flotation effect, reduces the consumption of flotation reagents, reduces production costs, and increases the comprehensive economic benefits;

[0018] (3) Skillfully based on the characteristics of zinc phases, different technological conditions are adopted for beneficiation products respectively for acid leaching purification - electrowinning treatment, which not only greatly improves the zinc recovery rate, but also reduces the production cost and increases the comprehensive economic benefits.

[0019] (4) Using this process to treat this type of zinc ore not only greatly improves the zinc recovery rate, but also reduces the production cost, improves the comprehensive economic benefits, achieves the purpose of comprehensive and efficient utilization of resources, and at the same time reduces the environmental pollution risk;

[0020] (5) This method has wide applicability to raw materials, is simple to operate, has low equipment requirements, is environmentally friendly, and effectively solves the technical problems of processing and utilization of such complex and difficult - to - treat zinc ore resources with multiple zinc occurrence states. It has wide industrial and commercial application and promotion value. Description of the Drawings

[0021] Figure 1 : Equipment connection diagram of a method for recycling complex zinc oxide ore with multiple zinc occurrence states;

[0022] Among them, 1: Jaw crusher, 2: Ball mill, 3: Pump sump, 4: Hydrocyclone, 5: Agitating tank, 6: Pulsating high - gradient high - intensity magnetic separator, 7: Flotation system, 8: Roasting rotary kiln, 9: Acid leaching purification - electrowinning system, 10: Acid leaching tank, 11: Filter, 12: Electrowinning tank. Embodiment

[0023] As Figure 1 shown, a complex zinc oxide ore recovery system with multiple zinc occurrence states includes a jaw crusher 1. The discharge port of the jaw crusher 1 is connected to the feed port of the ball mill 2. The discharge port of the ball mill 2 is connected to the upper feed port of the hydrocyclone 4 through a pump sump and a pump. The overflow outlet of the hydrocyclone 4 is connected to the feed port of the agitating tank A. The discharge port of the agitating tank A is connected to the feed port of the pulsating high - gradient high - intensity magnetic separator 6 through a pump. The concentrate outlet of the pulsating high - gradient high - intensity magnetic separator 6 is iron - containing zinc concentrate, and the concentrate outlet of the pulsating high - gradient high - intensity magnetic separator 6 is connected to the feed port of the acid leaching purification - electrowinning system; The tailing outlet of the pulsating high - gradient high - intensity magnetic separator 6 is connected to the flotation system after passing through the agitating tank B and the agitating tank C in sequence. The flotation concentrate outlet of the flotation system is connected to the feed port of the roasting rotary kiln 8. The slag outlet of the roasting rotary kiln 8 is connected to the feed port of the acid leaching purification - electrowinning system; The bottom settling outlet of the hydrocyclone 4 is connected to the feed port of the ball mill 2.

[0024] Preferably, the flotation system 7 includes a roughing system, a first scavenging system, a second scavenging system, a first cleaning system, and a second cleaning system; the roughing system is composed of 5 flotation machines connected in sequence from left to right, and the feed inlet of the first flotation machine in the roughing system is connected to the discharge outlet of the agitation tank C; the first scavenging system is composed of 4 flotation machines connected in sequence from left to right, and the tailing outlet of the last flotation machine in the roughing system is connected to the feed inlet of the first flotation machine in the first scavenging system; the foam tank of the first scavenging system is connected to the feed inlet of the first flotation machine in the roughing system; the second scavenging system is composed of 4 flotation machines connected in sequence from left to right, and the tailing outlet of the last flotation machine in the first scavenging system is connected to the feed inlet of the first flotation machine in the second scavenging system, the foam tank of the second scavenging system is connected to the feed inlet of the first flotation machine in the first scavenging system, and the tailing of the last flotation machine in the second scavenging system is the flotation tailing; the first cleaning system is composed of 4 flotation machines connected in reverse order (from right to left), the foam tank outlet of the flotation machine in the roughing system is connected to the feed inlet of the last flotation machine in the first cleaning system, and the tailing outlet of the first flotation machine in the first cleaning system is connected to the feed inlet of the first flotation machine in the roughing system; the second cleaning system is composed of 3 flotation machines connected in reverse order (from right to left), the foam tank outlet of the flotation machine in the first cleaning system is connected to the feed inlet of the last flotation machine in the second cleaning system, the tailing outlet of the first flotation machine in the second cleaning system is connected to the feed inlet of the last flotation machine in the first cleaning system, and the foam tank outlet of the flotation machine in the second cleaning system is the zinc concentrate. The first flotation machine is counted in sequence from left to right, and the last flotation machine is counted in sequence from left to right. Example

[0025] Raw material 1#: A certain zinc oxide ore, whose chemical composition is: Zn 14.97%, Fe 17.11%, SiO2 7.82, AL2O3 7.91% 、 CaO 14.34%, and its zinc phase components are: smithsonite 7.85%, zinc silicate 2.01%, zinc sulfide 0.68%, and zinc ferrite spinel 4.53%.

[0026] This process is implemented for this type of complex refractory zinc ore with multiple zinc occurrence states, and the technical steps include:

[0027] (1) Crush and grind the complex zinc oxide ore to a particle size of -0.074 mm accounting for 75% - 80%.

[0028] (2) Recover the encapsulated zinc oxide (siderite and zinc ferrite spinel) by pulsating high-gradient high-intensity magnetic separation. The pulp completed in the above step (1) is transported to the agitation tank A for pulp conditioning, and then enters the pulsating high-gradient high-intensity magnetic separator to recover siderite and zinc ferrite spinel, obtaining the encapsulated or combined zinc oxide concentrate I and the magnetic separation tailings. During this process, the magnetic separation concentration is 20%, the diameter of the magnetic medium is 1.5 mm, and the background magnetic induction intensity is 1.3 T.

[0029] (3) Flotation recovery of free zinc oxide (smithsonite and hemimorphite). The magnetic separation tailings obtained after completing the above step (2) are transported to agitation tank B, sodium hexametaphosphate is added for pulp conditioning, then to agitation tank C, flotation reagents are added for pulp conditioning, and then transported to the flotation system for flotation of free zinc oxide ore to obtain zinc oxide concentrate II and tailings. During this process, two rough selections, one roughing, and two scavengings are carried out; the dosage of sodium sulfide is 2500 g / t for roughing, 1000 g / t for the first scavenging, and 500 g / t for the second scavenging; the dosage of octadecylamine acetate is 150 g / t for roughing, 80 g / t for the first scavenging, and 40 g / t for the second scavenging; the dosage of kerosene is 100 g / t for roughing, 50 g / t for the first scavenging, and 25 g / t for the second scavenging; the dosage of No. 2 oil is 50 g / t for roughing, 30 g / t for the first scavenging, and 20 g / t for the second scavenging; the dosage of the dispersant sodium hexametaphosphate for roughing is 150 g / t; the flotation concentration for roughing is 20%.

[0030] (4) Roasting of zinc oxide concentrate II. The zinc oxide concentrate II obtained after completing the above step (3) is transported to a rotary kiln for low-temperature roasting to obtain zinc oxide roasted slag and flue gas (sent to the flue gas treatment tank). During this process, the roasting temperature is 400 °C.

[0031] (5) Acid leaching purification - electrowinning. The zinc oxide concentrate I containing encapsulated or combined zinc obtained after completing the above step (2) and the zinc oxide concentrate II roasted slag obtained after completing the above step (4) are respectively fed into the acid leaching - purification system for treatment to obtain zinc-containing acid leaching solution and acid leaching residues (including high-iron acid leaching residues and low-iron acid leaching residues). The zinc-containing acid leaching solution enters the electrowinning system for treatment to obtain high-quality zinc metal. During this process, for the acid leaching of encapsulated or combined zinc oxide concentrate I, sulfuric acid with an initial concentration of 2 mol / l is used, the molar ratio of sulfuric acid to iron and zinc is 1.2:1, the leaching temperature is 75 °C, the leaching time is 3 hours, and the purification is carried out by slowly adjusting the pH value to 5.4 using basic zinc carbonate or zinc oxide concentrate II roasted slag; for the acid leaching - purification of zinc oxide concentrate II roasted slag, the initial pH value is 2.0, slowly adjusted to pH value = 5.4, the leaching temperature is 75 °C, and the leaching time is 2 hours.

[0032] Through the implementation of the above steps, the zinc recovery rate reaches 80.56%. Example

[0033] Raw material 2#: A certain zinc oxide ore, whose chemical composition is: Zn 12.68%, Fe 17.69%, SiO2 19.31, AL2O3 9.47% 、 CaO 9.54%, and its zinc phase composition is 7.00% smithsonite, 1.38% zinc silicate, 0.63% zinc sulfide, and 3.67% zinc ferrite spinel.

[0034] Using this process to implement on this zinc oxide ore, the technical steps include:

[0035] (1) Crush and grind the complex zinc oxide ore to a particle size of -0.074 mm, with 75%-80% passing through the sieve.

[0036] (2) Recover the encapsulated zinc oxide (smithsonite and zinc ferrite spinel) by pulsating high-gradient high-intensity magnetic separation. The pulp after step (1) is transported to agitation tank A for pulp conditioning, and then enters a pulsating high-gradient high-intensity magnetic separator to recover smithsonite and zinc ferrite spinel, obtaining zinc oxide concentrate I containing encapsulated or combined zinc oxide and magnetic separation tailings. During this process, the magnetic separation concentration is 25%, the diameter of the magnetic medium is 2 mm, and the background magnetic induction intensity is 1.4 T.

[0037] (3) Recover the free zinc oxide (smithsonite and hemimorphite) by flotation. The magnetic separation tailings obtained after step (2) are transported to agitation tank B, and sodium hexametaphosphate is added for pulp conditioning. Then it goes to agitation tank C, and flotation reagents are added for pulp conditioning, and then it is transported to the flotation system for flotation of free zinc oxide ore, obtaining zinc oxide concentrate II and tailings. During this process, two-stage cleaning, one-stage roughing, and two-stage scavenging are carried out; the dosage of sodium sulfide for roughing is 2500 g / t, for scavenging 1 is 1000 g / t, and for scavenging 2 is 500 g / t; the dosage of octadecylamine acetate for roughing is 150 g / t, for scavenging 1 is 80 g / t, and for scavenging 2 is 40 g / t; the dosage of kerosene for roughing is 100 g / t, for scavenging 1 is 50 g / t, and for scavenging 2 is 25 g / t; the dosage of No. 2 oil for roughing is 50 g / t, for scavenging 1 is 30 g / t, and for scavenging 2 is 20 g / t; the dosage of sodium hexametaphosphate as the roughing dispersant is 150 g / t; the roughing flotation concentration is 22%.

[0038] (4) Roast zinc oxide concentrate II by flotation. The zinc oxide concentrate II obtained after step (3) is transported to a rotary kiln for low-temperature roasting, obtaining zinc oxide roasting slag and flue gas (sent to the flue gas treatment tank). During this process, the roasting temperature is 500 °C.

[0039] (5) Acid leaching purification - electrowinning. The zinc oxide concentrate I containing encapsulated or combined zinc obtained after step (2) and the zinc oxide roasting slag of zinc oxide concentrate II obtained after step (4) respectively enter the acid leaching - purification system for treatment, obtaining zinc-containing acid leaching solution and acid leaching slag (including high-iron acid leaching slag and low-iron acid leaching slag). The zinc-containing acid leaching solution enters the electrowinning system for treatment, obtaining high-quality zinc metal. During this process, for the acid leaching of zinc oxide concentrate I containing encapsulated or combined zinc, sulfuric acid with an initial concentration of 2 mol / l is used, the molar ratio of sulfuric acid to iron and zinc is 1.2:1, the leaching temperature is 80 °C, the leaching time is 4 hours, and for purification, basic zinc carbonate or zinc oxide roasting slag of zinc oxide concentrate II is slowly adjusted to pH = 5.4; for the acid leaching - purification of zinc oxide roasting slag of zinc oxide concentrate II by flotation, the initial pH value is 2.5, slowly adjusted to pH = 5.4, the leaching temperature is 80 °C, and the leaching time is 3 hours.

[0040] By implementing the above steps, the zinc recovery rate is 80.06%. Example

[0041] Raw material 3#: A certain zinc oxide ore, whose chemical composition is: Zn 12.27%, Fe 18.16%, SiO₂ 21.67%, Al₂O₃ 9.36% 、 CaO 11.55%, and its zinc phase components are smithsonite 6.67%, zinc silicate 1.21%, zinc sulfide 0.76%, and zinc ferrite spinel 3.67%.

[0042] Implement this process on this zinc oxide ore, and the technical steps include:

[0043] (1) Crush and grind the complex zinc oxide ore to a particle size where -0.074 mm accounts for 75% - 80%;

[0044] (2) Recover the encapsulated zinc oxide (siderite and zinc ferrite spinel) by pulsating high-gradient high-intensity magnetic separation. Transport the pulp that has completed the above step (1) to agitation tank A for pulp conditioning, and then enter the pulsating high-gradient high-intensity magnetic separator to recover siderite and zinc ferrite spinel, obtaining zinc oxide concentrate Ⅰ containing encapsulated or combined zinc oxide and magnetic separation tailings. During this process, the magnetic separation concentration is 25%, the diameter of the magnetic medium is 3 mm, and the background magnetic induction intensity is 1.4 T.

[0045] (3) Float to recover free zinc oxide (smithsonite and hemimorphite). Transport the magnetic separation tailings obtained from the above step (2) to agitation tank B, add sodium hexametaphosphate for pulp conditioning, then go to agitation tank C, add flotation reagents for pulp conditioning, and then transport to the flotation system for flotation of free zinc oxide ore, obtaining zinc oxide concentrate Ⅱ and tailings. During this process, two-stage cleaning, one-stage roughing, and two-stage scavenging are carried out; the dosage of sodium sulfide for roughing is 2500 g / t, for scavenging 1 is 1000 g / t, and for scavenging 2 is 500 g / t; the dosage of octadecylamine acetate for roughing is 150 g / t, for scavenging 1 is 80 g / t, and for scavenging 2 is 40 g / t; the dosage of kerosene for roughing is 100 g / t, for scavenging 1 is 50 g / t, and for scavenging 2 is 25 g / t; the dosage of No. 2 oil for roughing is 50 g / t, for scavenging 1 is 30 g / t, and for scavenging 2 is 20 g / t; the dosage of the dispersant sodium hexametaphosphate for roughing is 150 g / t; the roughing flotation concentration is 22%.

[0046] (4) Roast zinc oxide concentrate Ⅱ by flotation. Transport zinc oxide concentrate Ⅱ obtained from the above step (3) to a rotary kiln for low-temperature roasting, obtaining zinc oxide roasting slag and flue gas (sent to the flue gas treatment pond). During this process, the roasting temperature is 600 °C.

[0047] (5) Acid leaching purification - electrowinning. The zinc oxide concentrate I containing encapsulated or combined zinc obtained from the above step (2) and the roasted slag of zinc oxide concentrate II obtained from the above step (4) are respectively fed into the acid leaching - purification system for treatment to obtain zinc - containing acid leaching solution and acid leaching residues (including high - iron acid leaching residues and low - iron acid leaching residues). Then, the zinc - containing acid leaching solution enters the electrowinning system for treatment to obtain high - quality zinc metal. In this process, for the acid leaching of the encapsulated or combined zinc oxide concentrate I, sulfuric acid with an initial concentration of 2 mol / l is used, the molar ratio of sulfuric acid to iron and zinc is 1.2:1, the leaching temperature is 80 °C, and the leaching time is 3 - 4 hours. For purification, basic zinc carbonate or the roasted slag of zinc oxide concentrate II is slowly added to adjust the pH value to 5.4; for the acid leaching - purification of the roasted slag of flotation zinc oxide concentrate II, the initial pH value is 2.5, which is slowly adjusted to pH value 5.4, the leaching temperature is 80 °C, and the leaching time is 3 hours.

[0048] By implementing the above steps, the zinc recovery rate is 78.88%. Example

[0049] Raw material 4#: A certain zinc oxide ore, whose chemical composition is: Zn 10.59%, Fe 17.33%, SiO₂ 16.74%, Al₂O₃ 9.45% 、 CaO 11.75%, and its zinc phase composition is: smithsonite 5.87%, zinc silicate 1.12%, zinc sulfide 0.63%, zinc ferrite spinel 2.97%.

[0050] Using this process to implement on this zinc oxide ore, the technical steps include:

[0051] (1) Crush and grind the complex zinc oxide ore to a particle size where - 0.074 mm accounts for 75% - 80%;

[0052] (2) Pulse high - gradient high - intensity magnetic separation to recover encapsulated zinc oxide (ferro - smithsonite and zinc ferrite spinel). The pulp completed in the above step (1) is transported to the agitation tank A for pulp adjustment, and then enters the pulse high - gradient high - intensity magnetic separator to recover ferro - smithsonite and zinc ferrite spinel, obtaining zinc oxide concentrate I containing encapsulated or combined zinc and magnetic separation tailings. In this process, the magnetic separation concentration is 20%, the diameter of the magnetic medium is 1.5 mm, and the background magnetic induction intensity is 1.4 T.

[0053] (3) Flotation recovery of free zinc oxide (smithsonite and hemimorphite). The magnetic separation tailings obtained from the above step (2) are transported to agitation tank B, and sodium hexametaphosphate is added for pulp conditioning. Then it goes to agitation tank C, where flotation reagents are added for pulp conditioning, and then it is transported to the flotation system for flotation of free zinc oxide ore to obtain zinc oxide concentrate II and tailings. During this process, two-stage cleaning, one-stage roughing, and two-stage scavenging are carried out; the dosage of sodium sulfide is 2500 g / t for roughing, 1000 g / t for the first scavenging, and 500 g / t for the second scavenging; the dosage of octadecylamine acetate is 150 g / t for roughing, 80 g / t for the first scavenging, and 40 g / t for the second scavenging; the dosage of kerosene is 100 g / t for roughing, 50 g / t for the first scavenging, and 25 g / t for the second scavenging; the dosage of No. 2 oil is 50 g / t for roughing, 30 g / t for the first scavenging, and 20 g / t for the second scavenging; the dosage of the dispersant sodium hexametaphosphate for roughing is 150 g / t; the roughing flotation concentration is 20%.

[0054] (4) Roasting of zinc oxide concentrate II. The zinc oxide concentrate II obtained from the above step (3) is transported to a rotary kiln for low-temperature roasting to obtain zinc oxide roasted slag and flue gas (sent to the flue gas treatment tank). During this process, the roasting temperature is 400 °C.

[0055] (5) Acid leaching purification - electrowinning. The zinc oxide concentrate I containing encapsulated or combined zinc obtained from the above step (2) and the zinc oxide concentrate II roasted slag obtained from the above step (4) are separately fed into the acid leaching - purification system for treatment to obtain zinc-containing acid leaching solution and acid leaching residues (including high-iron acid leaching residues and low-iron acid leaching residues). Then, the zinc-containing acid leaching solution enters the electrowinning system for treatment to obtain high-quality zinc metal. During this process, for the acid leaching of the encapsulated or combined zinc oxide concentrate I, sulfuric acid with an initial concentration of 2 mol / l is used, the molar ratio of sulfuric acid to iron and zinc is 1.2:1, the leaching temperature is 80 °C, and the leaching time is 4 hours. The purification is carried out by slowly adjusting the pH value to 5.4 with basic zinc carbonate or zinc oxide concentrate II roasted slag; for the acid leaching - purification of the zinc oxide concentrate II roasted slag, the initial pH value is 2.0, and it is slowly adjusted to pH value = 5.4, the leaching temperature is 75 °C, and the leaching time is 2 hours.

[0056] Through the implementation of the above steps, the zinc recovery rate reaches 77.13%.

[0057] To sum up, by adopting this process for the implementation of this type of complex zinc oxide ore with various zinc occurrence states, the obtained zinc recovery rate is stably between 77% - 81%. Generally speaking, this method has a wide applicability to raw materials, simple operation, low equipment requirements, is environmentally friendly, effectively solves the technical problems of processing and utilization of this type of complex refractory zinc ore resources with various zinc occurrence states, and has relatively low production costs, can obtain good economic benefits, and the mineral resources are efficiently and comprehensively utilized, having good industrial and commercial promotion and application value.

Claims

1. A method for recycling a complex zinc oxide ore with multiple zinc occurrence states, characterized in that, The specific steps are as follows: (1) Crush and grind the complex zinc oxide ore to a particle size where -0.074 mm accounts for 75% - 80%; (2) Recover the encapsulated zinc oxide by pulsating high-gradient high-intensity magnetic separation. After adjusting the pulp of the ore in step (1), feed it into a pulsating high-gradient high-intensity magnetic separator to recover smithsonite and zinc ferrite spinel, obtaining zinc oxide concentrate I containing encapsulated or combined zinc oxide and magnetic separation tailings. During this process, the magnetic separation concentration is 20% - 25%, the diameter of the magnetic medium is 1.5 mm - 3 mm, and the background magnetic induction intensity is 1.3 T - 1.4 T; (3) Recover the free zinc oxide by flotation. Add sodium hexametaphosphate to the magnetic separation tailings obtained in step (2) for pulp adjustment, then add flotation reagents for pulp adjustment, and then transport it to the flotation system for flotation of the free zinc oxide ore, obtaining zinc oxide concentrate II and tailings; (4) Roast the zinc oxide concentrate II by flotation. Transport the zinc oxide concentrate II obtained in step (3) to a rotary kiln for low-temperature roasting, obtaining zinc oxide roasting slag and flue gas, and the flue gas goes to the flue gas treatment pond; Acid leaching purification - electrowinning. The zinc oxide concentrate I of encapsulated or combined zinc obtained in step (2) and the zinc oxide roasting slag of the zinc oxide concentrate II obtained in step (4) are respectively fed into the acid leaching purification system for treatment, obtaining zinc-containing acid leaching solution and acid leaching slag. The zinc-containing acid leaching solution enters the electrowinning system for treatment to obtain high-quality zinc metal.

2. The recovery method of a complex zinc oxide ore with multiple zinc occurrence states as described in claim 1, characterized in that In step (3), the flotation system includes two rough selections, one roughing, and two scavengings; the dosage of sodium sulfide for roughing is 2500 g / t, for scavenging 1 is 1000 g / t, and for scavenging 2 is 500 g / t; the dosage of octadecylamine acetate for roughing is 150 g / t, for scavenging 1 is 80 g / t, and for scavenging 2 is 40 g / t; the dosage of kerosene for roughing is 100 g / t, for scavenging 1 is 50 g / t, and for scavenging 2 is 25 g / t; the dosage of No. 2 oil for roughing is 50 g / t, for scavenging 1 is 30 g / t, and for scavenging 2 is 20 g / t; the dosage of the roughing dispersant sodium hexametaphosphate is 150 g / t; the roughing flotation concentration is 20% - 22%.

3. The recovery method of a complex zinc oxide ore with multiple zinc occurrence states as described in claim 1, characterized in that In step (4), roast the zinc oxide concentrate II by flotation. Transport the zinc oxide concentrate II obtained after completing the above step (3) to a rotary kiln for low-temperature roasting, and the roasting temperature is 400°C - 600°C.

4. The recovery method of a complex zinc oxide ore with multiple zinc occurrence states as described in claim 1, characterized in that In step (5), for acid leaching of the zinc oxide concentrate I of encapsulated or combined zinc, sulfuric acid with an initial concentration of 2 mol / l is used, and the molar ratio of sulfuric acid to iron and zinc is 1.2:

1. The leaching temperature is 75°C - 80°C, and the leaching time is 3 - 4 hours. For purification, it is slowly adjusted to pH = 5.4 using basic zinc carbonate or the zinc oxide roasting slag of the zinc oxide concentrate II; for acid leaching purification of the zinc oxide roasting slag of the zinc oxide concentrate II by flotation, the initial pH value is 2.0 - 2.5, slowly adjusted to pH = 5.4, the leaching temperature is 75°C - 80°C, and the leaching time is 2 - 3 hours.

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