A zinc smelting slag treatment device

Abstract

A zinc smelting slag treatment device belongs to the field of ore dressing and metallurgy. The zinc smelting slag treatment device of the present invention includes: a feed bin, a feeding belt, a screw feeder I, a cyclone preheater, a suspension heating roasting furnace, a cyclone separator, a suspension sulfurization roaster, a cooler, a ball mill, a flotation machine, a cooling device, a dust collector, a fan, a chimney, a screw feeder II, a burner, and a gas locking valve. By using the system of the present invention to treat zinc smelting slag, the application range of the suspension roasting process is expanded, and the self-heating sulfurization of minerals in a suspended state is fully utilized, solving problems such as poor product uniformity, high energy consumption, and poor environmental friendliness. High-grade sulfide ore concentrates can be produced through subsequent flotation. In addition, this process has the advantages of environmental friendliness, low treatment cost, good economy, simple process flow, and easy industrial application.

Description

Technical Field

[0001] The invention belongs to the field of smelting, and in particular relates to a device and method for treating zinc smelting slag. Background Art

[0002] Zinc, as an important non-ferrous metal, is widely used in various fields. In recent years, with the increase in my country's demand for raw materials, zinc smelting has developed rapidly. A large amount of zinc smelting slag is produced every year, causing serious pollution and waste of the land and natural environment. Therefore, it is urgent to further strengthen the utilization and treatment of zinc smelting slag. At present, the conventional zinc smelting slag treatment methods mainly include hydrometallurgy, pyrometallurgy and mineral processing. Pyrometallurgy has the advantages of a wide range of raw materials, simple process and high recovery efficiency, but the disadvantages of high energy consumption and high pollution make pyrometallurgy face serious tests under the current environmental protection policy. At present, pyrometallurgy mainly includes rotary kiln roasting method, fuming furnace blowing method, Ausmelt method, etc. Hydrometallurgy has the characteristics of low energy consumption, strong selectivity for raw materials, and less environmental damage compared to pyrometallurgy. However, at present, hydrometallurgy is also less used in the practical application of zinc smelting slag treatment due to its complicated process and high cost. The ore dressing method is to separate useful minerals from gangue minerals by recovering sulfide in zinc smelting slag through flotation reagents, which requires a large amount of sulfiding agents and other flotation reagents, and the recovery cost is extremely high. Therefore, the current focus of zinc resource technology research and innovation is to achieve an efficient, energy-saving and high resource recovery rate zinc smelting slag treatment method through new methods and new devices.

[0003] At present, in the recovery of useful minerals from zinc smelting slag, a combined method of dressing and smelting is generally adopted. The application field of using suspended sulfidation roasting to recover zinc smelting slag is still to be explored, and there is no case of developing a suspended sulfidation roasting device for zinc smelting slag. Patent CN201710139780.1 provides a method for recovering lead and zinc from lead sulfate by enhanced sulfidation roasting-flotation. This method uses a method of adding a sulfiding agent to conventional roasting to conduct an enhanced sulfidation-flotation recovery process for lead-zinc sulfate slag, and can obtain a sulfide ore concentrate of a certain grade. However, this process method has the problems of uneven heating during the roasting process, too long roasting time, great energy loss during the roasting process, and too many impurities during the flotation process, which greatly increases the cost of industrial production. Patent CN202010473986.X discloses a suspension roasting system for carbon-containing gold ore, and proposes to treat carbon-containing gold ore by pre-oxidation suspension roasting and strong oxidation suspension roasting. The invented device has the advantages of uniform heating during suspension roasting, thorough desulfurization and decarbonization, and high heat conduction efficiency compared to conventional roasting. However, this method is only used to treat carbon-containing gold ore, and secondary resources such as zinc smelting slag are not recycled, and the system does not consider treatment processes involving sulfidation reaction and addition of sulfiding agent.

[0004] Therefore, it is urgent to develop a process equipment for efficiently treating zinc smelting slag at present to realize the comprehensive utilization of secondary resources. Developing a device with high efficiency, low pollution and maximized economic cost is the key to realizing the industrialization of zinc smelting slag recycling. Summary of the Invention

[0005] Aiming at the problems existing in the existing process equipment for recycling zinc smelting slag, such as low efficiency, high energy consumption, serious environmental pollution, uneven product quality, etc., the primary object of the present invention is to provide a device that can efficiently and low-energy consume zinc smelting slag.

[0006] The zinc smelting slag treatment device of the present invention includes: a feeding bin, a feeding belt, a screw feeder I, a cyclone preheater, a suspension heating roasting furnace, a cyclone separator, a suspension sulfidation roaster, a cooler, a ball mill, a flotation machine, a cooling device, a dust collector, a fan, a chimney, a screw feeder II, a burner, and a gas lock valve.

[0007] They are connected and combined in the following way:

[0008] The feeding bin is connected to the feeding port of the screw feeder I through the feeding belt, and the discharging port of the screw feeder I is connected to the feeding port of the cyclone preheater through a pipeline;

[0009] The upper gas outlet of the cyclone preheater is connected to the feeding port of the cooling device, the discharging port of the cooling device is connected to the feeding port of the dust collector, the discharging port of the dust collector is connected to the fan, and the fan is connected to the chimney;

[0010] The lower discharging port of the cyclone preheater is connected to the feeding end of the gas lock valve, the discharging end of the gas lock valve is connected to the feeding port of the suspension heating roasting furnace, and the discharging port of the suspension roasting furnace is connected to the feeding port of the cyclone separator through a pipeline;

[0011] The lower discharging port of the cyclone separator is connected to the feeding port of the suspension sulfidation roaster, the discharging port of the suspension sulfidation roaster is connected to the feeding port of the cooler, the discharging port of the cooler is connected to the feeding port of the ball mill, and the discharging port of the ball mill is connected to the flotation machine.

[0012] The side exhaust hole of the cooler is connected to the air inlet of the suspension heating roasting furnace, and a nitrogen inlet is arranged at the bottom of the cooler for cooling.

[0013] In the device, the screw feeder II is connected to the feeding port of the suspension sulfidation roaster.

[0014] In the device, a burner is arranged at the bottom of the suspension heating roasting furnace, which is connected to gas and air. The zinc smelting slag is in a suspended state under the action of air flow and negative pressure in the suspension heating roasting furnace.

[0015] In the said device, a plurality of air inlets are provided at the bottom of the suspension sulfurization roaster, which are respectively communicated with nitrogen and coal gas gas sources.

[0016] In the said device, the upper gas outlet of the cyclone separator is communicated with the side air inlet of the cyclone preheater.

[0017] In the said device, thermocouple temperature measuring devices and pressure sensor devices are provided inside the cyclone preheater, suspension heating roaster, suspension sulfurization roaster, cooler and cyclone separator, and the temperatures of each temperature measuring point and the pressures of each pressure measuring point are monitored in real time through a computer.

[0018] The usage method of the said zinc smelting slag treatment device is carried out according to the following steps:

[0019] (1) Feed the zinc smelting slag from the feed bin, convey it to the screw feeder I through the feeding belt, and then convey it to the cyclone preheater through the screw feeder I for preheating. The preheating temperature is 150 - 350 °C, and the preheating time is 5 - 15 s to dry and dehydrate the raw materials and reduce the time in the suspension heating roaster.

[0020] (2) Feed the dried zinc smelting slag from the lower discharge port of the cyclone preheater into the suspension heating roaster through the air lock valve. The burner at the bottom inside the suspension heating roaster injects coal gas to generate high-temperature flue gas. The zinc smelting slag is in a suspended state under the action of the gas flow and negative pressure in the suspension heating roaster and is heated to 600 - 1000 °C. The roasting time is 5 - 20 s. Impurities such as carbonate groups and hydroxyl groups in the zinc smelting slag are removed in the suspension heating roaster. Some possible reaction equations are as follows. The useful minerals in the zinc smelting slag undergo decomposition and reduction reactions to generate oxidized metals and sulfide metals.

[0021] PbCO3 = PbO + CO2(g)

[0022] ZnCO3 = ZnO + CO2(g)

[0023] PbSO4 + 4CO(g) = PbS + 4CO2(g)

[0024] ZnSO4 + 4CO(g) = ZnS + 4CO2(g)

[0025] 2PbSO4 = 2PbO + 2SO2(g) + O2(g)

[0026] 2ZnSO4 = 2ZnO + 2SO2(g) + O2(g)

[0027] ZnFe2O4 + CO(g) = 2FeO + ZnO + CO2(g)

[0028] (3) The zinc smelting slag after suspension heating roasting pretreatment enters the cyclone separator. The flue gas is discharged from the upper gas outlet of the cyclone separator and fed into the cyclone preheater. The zinc smelting slag is discharged from the lower discharge port of the cyclone separator and fed into the suspension sulfurization roaster. Nitrogen and coal gas are introduced into the bottom gas inlet of the suspension sulfurization roaster. The sulfurizing agent is fed into the suspension sulfurization roaster from the screw feeder II. The zinc smelting slag is in a suspended state under the airflow and negative pressure conditions, and undergoes a sulfurization reaction with the sulfurizing agent using its own stored heat. The roasting temperature is 450 - 800 °C, and the roasting time is 15 - 60 min. The reaction equations are as follows.

[0029] Zn2SiO4 + 3FeS2 = SiO2 + 2ZnS + SO2(g) + 3FeS

[0030] 2PbO + 3FeS2 = 2PbS + SO2(g) + 3FeS

[0031] 2ZnO + 3FeS2 = 2ZnS + SO2(g) + 3FeS

[0032] PbO + S + CO = PbS + CO2(g)

[0033] ZnO + S + CO = ZnS + CO2(g)

[0034] (4) The zinc smelting slag is discharged from the discharge port of the suspension sulfurization roaster and enters the cooler. Nitrogen is introduced into the bottom of the cyclone cooler for cooling, and it is cooled at a rate of 100 - 400 °C / h to 60 - 100 °C. The gas generated during the cooling process of the cooler is discharged through the side exhaust holes and enters the suspension heating roasting furnace as heating gas. The material cooled by the cooler is discharged from the discharge port and fed into the ball mill. After grinding, it enters the flotation machine for conventional flotation separation to obtain sulfide ore concentrate.

[0035] In the above method, the zinc smelting slag in the feed bin is zinc hydrometallurgy slag or pyrometallurgy slag, and the useful mineral components are mainly zinc oxide / lead, lead sulfate / zinc, zinc ferrite, and zinc silicate. The main chemical component mass percentages are: Pb 1 - 10%, Zn 5 - 25%, Fe 5 - 30%, and the particle size -0.074 mm accounts for no less than 80%.

[0036] In the above method, the coal gas is producer gas, coke oven gas, blast furnace gas, converter gas, or pyrolytic natural gas.

[0037] In the above method, the sulfurizing agent can be pyrite, pyrrhotite, sulfur, or elemental sulfur, or a mixture of these. The addition amount is controlled at 1% - 10% of the zinc smelting slag amount according to the composition of different zinc smelting slags.

[0038] In the above method, the gas separated in the cyclone preheater is discharged from the gas outlet of the cyclone preheater into the cooling device. After being cooled by the cooling device, the gas is introduced into the dust collector. After being dust-removed by the dust collector, the gas is introduced into the fan. Finally, the gas discharged by the fan is discharged through the chimney.

[0039] In the above method, the volume concentration of the coal gas in the suspension heating and roasting furnace is 20% - 60%.

[0040] In the above method, the particle size of the mineral after grinding by the ball mill is such that the proportion of -0.032 mm is not less than 80%.

[0041] In the above method, when introducing coal gas and nitrogen from the bottom of the suspension sulfurization roaster, the input amount of the coal gas is 1.0 - 1.5 times the theoretical amount required for the complete reaction of H2 / CO in the coal gas with all the zinc element phases in the zinc smelting slag being zinc oxide.

[0042] In the above method, through the thermocouple temperature measurement device and pressure sensor device provided inside the cyclone heater, suspension heating roasting furnace, suspension sulfurization roaster, cooler, and cooling device, the temperature of each temperature measurement point and the pressure of each pressure measurement point are monitored in real time.

[0043] Advantages of the present invention:

[0044] Compared with the current traditional sulfurization roasting and traditional zinc smelting slag treatment processes, the present process adopts the new technology of suspension sulfurization roasting phase reconstruction. By using the device of the present invention to treat zinc smelting slag, the application range of the suspension roasting process is expanded, and the self-heating sulfurization of minerals in the suspended state is fully utilized, solving problems such as poor product uniformity, high energy consumption, and poor environmental friendliness. Through subsequent flotation, sulfide ore concentrates with higher grades can be produced. In addition, this process has the advantages of environmental friendliness, low treatment cost, good economy, simple process flow, and easy industrial application. Description of the drawings

[0045] Figure 1 Schematic diagram of the zinc smelting slag treatment device. In the figure, 1 - feed bin, 2 - feeding belt, 3 - screw feeder I, 4 - cyclone preheater, 5 - suspension heating roasting furnace, 6 - cyclone separator, 7 - suspension sulfurization roaster, 8 - cooler, 9 - ball mill, 10 - flotation machine, 11 - cooling device, 12 - dust collector, 13 - fan, 14 - chimney, 15 - screw feeder II, 16 - burner, 17 - air lock valve. Detailed implementation manners

[0046] The present invention will be further described below in conjunction with the drawings and specific examples.

[0047] Example 1

[0048] A zinc smelting slag treatment device, as Figure 1As shown in the figure, it includes: 1. Feed bin, 2. Feeding belt, 3. Screw feeder I, 4. Cyclone preheater, 5. Suspension heating roasting furnace, 6. Cyclone separator, 7. Suspension sulfurization roaster, 8. Cooler, 9. Ball mill, 10. Flotation machine, 11. Cooling device, 12. Dust collector, 13. Fan, 14. Chimney, 15. Screw feeder II, 16. Burner, 17. Air lock valve.

[0049] Link and combine in the following way:

[0050] The feed bin 1 is connected to the feed inlet of the screw feeder I 3 through the feeding belt 2, and the discharge outlet of the screw feeder I 3 is connected to the feed inlet of the cyclone preheater 4 through a pipeline;

[0051] The upper gas outlet of the cyclone preheater 4 is connected to the feed inlet of the cooling device 11, the discharge outlet of the cooling device 11 is connected to the feed inlet of the dust collector 12, the discharge outlet of the dust collector 12 is connected to the fan 13, and the fan 13 is connected to the chimney 14;

[0052] The lower discharge outlet of the cyclone preheater 4 is connected to the feed end of the air lock valve 17, the discharge end of the air lock valve 17 is connected to the feed inlet of the suspension heating roasting furnace 5, the discharge outlet of the suspension roasting furnace 5 is connected to the feed inlet of the cyclone separator 6 through a pipeline, a burner 16 is provided at the bottom of the suspension heating roasting furnace 5 and is connected to gas and air, and the upper gas outlet of the cyclone separator 6 is connected to the side air inlet of the cyclone preheater 4 through a pipeline;

[0053] The lower discharge outlet of the cyclone separator 6 is connected to the feed inlet of the suspension sulfurization roaster 7, the feed inlet of the suspension sulfurization roaster 7 is also connected to the screw feeder II 15, two air inlets are provided at the bottom of the suspension sulfurization roaster 7 and are respectively connected to the nitrogen and gas gas sources, the discharge outlet of the suspension sulfurization roaster 7 is connected to the feed inlet of the cooler 8, the side exhaust hole of the cooler 8 is connected to the air inlet of the suspension heating roasting furnace 5, a nitrogen air inlet is provided at the bottom of the cooler 8, the discharge port of the cooler 8 is connected to the feed inlet of the ball mill 9, and the discharge outlet of the ball mill 9 is connected to the flotation machine 10;

[0054] In the said device, thermocouple temperature measuring devices and pressure sensor devices are provided inside the cyclone preheater 4, suspension heating roasting furnace 5, suspension sulfurization roaster 7, cooler 8, and cyclone separator 6, and the temperature of each temperature measuring point and the pressure of each pressure measuring point are monitored in real time through a computer.

[0055] Example 2

[0056] The usage method of the zinc smelting slag treatment device described in Example 1 is as follows. The specific operation steps include:

[0057] The zinc smelting slag used in this embodiment contains 4.23% Pb, 19.53% Zn, 15.23% Fe, 20.42% SiO2, 5.5% S, and 6.12% CaO by mass percentage of the main components. The chemical phases of lead are: 88% PbSO4, 6% PbS, and 6% others. The chemical phase analysis of zinc is: 73% ZnSO4, 15% ZnS, 10% ZnFe3O4, and 2% others.

[0058] The particle size of the zinc smelting slag with -0.074mm accounts for 85%.

[0059] (1) The zinc smelting slag is conveyed from the feed bin 1 to the screw feeder I 3 through the feeding belt 2, and then conveyed to the cyclone preheater 4 by the screw feeder I 3 for preheating. The preheating temperature is 200°C and the preheating time is 8s to preheat and dry the raw materials and remove the surface-attached water.

[0060] (2) The dried zinc smelting slag is fed into the suspension heating roasting furnace 5 through the air lock valve 17 at the lower discharge port of the cyclone preheater 4. Gas is introduced into the burner 16 at the bottom inside the suspension heating roasting furnace 5, and air is introduced into the suspension heating roasting furnace 5 from the air inlet. The volume concentration of gas inside the suspension heating roasting furnace 5 is 50%. The zinc smelting slag is in a suspended state under the action of air flow and negative pressure inside the suspension heating roasting furnace 5 and is heated to 850°C. The suspension roasting time is 10s. The zinc smelting slag removes the crystal water inside the suspension heating roasting furnace 5, and compounds such as zinc carbonate and zinc sulfate undergo decomposition and reduction reactions to generate zinc oxide and zinc sulfide, etc.

[0061] (3) The zinc smelting slag processed by the suspension heating roasting furnace 5 is sent into the cyclone separator 6. The flue gas is discharged from the upper gas outlet of the cyclone separator 6 and fed into the cyclone preheater 4 as part of the heating gas in the cyclone preheater 4. The flue gas discharged from the gas outlet of the cyclone preheater 4 is introduced into the cooling device 11, and after cooling, it enters the dust collector 12. The dust collector 12 is connected to the fan 13, and finally, it is discharged through the chimney 14 by the fan 13.

[0062] The zinc smelting slag is discharged from the lower discharge port of the cyclone separator 6 and fed into the suspension sulfurization roaster 7. Nitrogen and gas are introduced into the bottom air inlet of the suspension sulfurization roaster 7. The gas input amount is 1.1 times the theoretical amount required for the complete reaction of H2 / CO in the gas with all the zinc element phases in the zinc smelting slag being zinc oxide. Pyrite is fed into the suspension sulfurization roaster 7 as a sulfurizing agent from the screw feeder II 15. The zinc smelting slag is in a suspended state under the air flow and negative pressure, and undergoes a sulfurization reaction with the sulfurizing agent. The roasting temperature is 700°C, the roasting time is 40min, and the pyrite addition amount is 1.5% of the mass of the zinc smelting slag.

[0063] (4) The zinc smelting slag enters the cooler 8 from the discharge port of the suspension sulfidation roasting furnace 7. Nitrogen is introduced into the bottom of the cooler 8 and cooled at a rate of 100 °C / h to 80 °C for the material. The gas generated during the cooling process is discharged from the cooler 8 and enters the suspension heating roasting furnace 5 as heating gas. The material is discharged from the discharge port of the cooler 8 and enters the ball mill 9. When the grinding reaches a particle size of -0.032 mm with a proportion of 80%, the obtained material is sent to the flotation machine 10 for conventional flotation separation. Finally, the recovery rates of zinc and lead concentrates are 80.38% and 78.23% respectively, and the grades are 39.4% and 46.9% respectively.

[0064] Example 3

[0065] The usage method of the zinc smelting slag treatment device described in Example 1 is as follows. The specific operation steps include:

[0066] The zinc smelting slag contains 1.15% Pb, 20.53% Zn, 25.26% Fe, 22.26% SiO2, 3.26% Al2O3, 4.84% CaO, and 2.1% MgO by mass percentage of the main components. The chemical phase analysis of zinc is: 8.22% ZnSO4, 37.5% ZnFe3O4, 51.28% ZnSiO3, and 3% ZnO.

[0067] The particle size of the zinc smelting slag is 95% with a particle size of -0.074 mm.

[0068] (1) The zinc smelting slag is transported from the feeding bin 1 to the screw feeder I 3 through the feeding belt, and then transported to the cyclone preheater 4 for preheating. The preheating temperature is 250 °C and the preheating time is 5 s. The raw material is preheated and dried to remove the surface attached water.

[0069] (2) The dried zinc smelting slag is fed into the suspension heating roasting furnace 5 from the lower discharge port of the cyclone preheater 4 through the air lock valve 17. Gas is introduced into the burner 16 at the bottom of the suspension heating roasting furnace 5, and air is introduced into the suspension heating roasting furnace 5 from the air inlet. The volume concentration of gas in the suspension heating roasting furnace 5 is 40%. The zinc smelting slag is in a suspended state under the action of air flow and negative pressure in the suspension heating roasting furnace 5 and is heated to 800 °C. The roasting time is 5 s. The zinc smelting slag removes crystal water in the suspension heating roasting furnace 5, and compounds such as zinc carbonate and zinc sulfate undergo decomposition and reduction reactions to generate zinc oxide and zinc sulfide, etc.

[0070] (3) Feed the zinc smelting slag treated by the suspension heating roaster 5 into the cyclone separator 6. The flue gas is discharged from the upper gas outlet of the cyclone separator 6 and fed into the cyclone preheater 4, serving as part of the heating gas in the cyclone preheater 4. The flue gas discharged from the outlet of the cyclone preheater 4 is introduced into the cooling device 11, and after cooling, it enters the dust collector 12. The dust collector 12 is connected to the fan 13, and finally, it is discharged through the chimney 14 via the fan.

[0071] The zinc smelting slag is discharged from the lower discharge port of the cyclone separator 6 and fed into the suspension sulfurization roaster 7. Nitrogen and gas are introduced into the bottom air inlet of the suspension sulfurization roaster 7. The gas flow rate is 1.3 times the theoretical amount required for the complete reaction of H2 / CO in the gas with all the zinc element phases in the zinc smelting slag being zinc oxide. Elemental sulfur is fed into the suspension sulfurization roaster 7 as a sulfurizing agent from the screw feeder II 15. The zinc smelting slag is in a suspended state under the action of the gas flow and negative pressure, and undergoes a sulfurization reaction with the sulfurizing agent. The roasting temperature is 700 °C, the roasting time is 30 min, and the addition amount of elemental sulfur is 3% of the mass of the zinc smelting slag.

[0072] (4) The zinc smelting slag enters the cooler 8 from the discharge port of the suspension sulfurization roaster 7. Nitrogen is introduced into the bottom of the cooler 8 to cool it at a rate of 100 °C / h until the material reaches 100 °C. The gas generated during the cooling process is discharged from the cooler 8 and enters the suspension heating roaster 5 as heating gas. The material is discharged from the discharge port of the cooler 8 and enters the ball mill 9. When the grinding particle size with a particle size of -0.032 mm accounts for 85%, the obtained material is fed into the flotation machine 10 for conventional flotation separation. Finally, the recovery rate of zinc concentrate is 79.38% and the grade is 41.2%.

Claims

1. A method for treating zinc smelting slag, characterized in that, The steps are as follows: (1) Feed the zinc smelting slag from the feed bin, convey it to the screw feeder I through the feeding belt, and then convey it to the cyclone preheater for preheating. The preheating temperature is 150 - 350 °C, and the preheating time is 3 - 15 s to dry and dehydrate the raw materials, reducing the time in the suspension heating roasting furnace; (2) Feed the dried zinc smelting slag from the lower discharge port of the cyclone preheater into the suspension heating roasting furnace through the air lock valve. The burner at the bottom of the suspension heating roasting furnace is fed with gas to generate high-temperature flue gas. The zinc smelting slag is in a suspended state under the action of air flow and negative pressure in the suspension heating roasting furnace and is heated to 600 - 1000 °C. The roasting time is 5 - 20 s. In the suspension heating roasting furnace, impurities in the zinc smelting slag including carbonate and hydroxyl groups are removed, and the useful minerals in the zinc smelting slag undergo decomposition and reduction reactions to generate oxidized metals and sulfide metals; the volume concentration of gas in the suspension heating roasting furnace is 20% - 60%; (3) The zinc smelting slag pretreated by suspension heating roasting enters the cyclone separator. The flue gas is discharged from the upper gas outlet of the cyclone separator and fed into the cyclone preheater. The zinc smelting slag is discharged from the lower discharge port of the cyclone separator and fed into the suspension sulfurization roaster. Nitrogen and gas are fed into the bottom air inlet of the suspension sulfurization roaster; the sulfurizing agent is fed into the suspension sulfurization roaster from the screw feeder II. The zinc smelting slag is in a suspended state under the action of air flow and negative pressure and undergoes a sulfurization reaction with the sulfurizing agent using its own stored heat. The roasting temperature is 450 - 800 °C, and the roasting time is 15 - 60 min; when gas and nitrogen are fed into the bottom of the suspension sulfurization roaster, the feeding amount of gas is 1.0 - 1.5 times the theoretical amount required for the complete reaction of H2 / CO in the gas with all the zinc-phase substances in the zinc smelting slag being zinc oxide; (4) The zinc smelting slag is discharged from the discharge port of the suspension sulfurization roaster and enters the cooler. Nitrogen is fed into the bottom of the cyclone cooler for cooling. The gas generated during the cooling process of the cooler is discharged through the side exhaust holes and enters the suspension heating roasting furnace as heating gas. The material cooled by the cooler is discharged from the discharge port and fed into the ball mill. After grinding, it enters the flotation machine for conventional flotation separation to obtain sulfide ore concentrate.

2. The method for treating zinc smelting slag according to claim 1, wherein, The zinc smelting slag in the feed bin is zinc hydrometallurgy slag or pyrometallurgy slag, and the proportion of particles with a size of -0.074 mm is not less than 80%.

3. A method for treating zinc smelting slag according to claim 1, characterized in that, After grinding by the ball mill, the proportion of minerals with a size of -0.032 mm is not less than 80%.

4. A method for treating zinc smelting slag according to claim 1, characterized in that, The devices used include: feed bin, feeding belt, screw feeder I, cyclone preheater, suspension heating roasting furnace, cyclone separator, suspension sulfurization roaster, cooler, ball mill, flotation machine, cooling device, dust collector, fan, chimney, screw feeder II, burner, air lock valve; The feed bin is connected to the feed inlet of the screw feeder I through the feeding belt, and the discharge outlet of the screw feeder I is connected to the feed inlet of the cyclone preheater through a pipeline; The upper gas outlet of the cyclone preheater is connected to the feed inlet of the cooling device, the discharge outlet of the cooling device is connected to the feed inlet of the dust collector, the discharge outlet of the dust collector is connected to the fan, and the fan is connected to the chimney; The lower discharge port of the cyclone preheater is connected to the feeding end of the air lock valve, the discharging end of the air lock valve is connected to the feeding port of the suspension heating roasting furnace, and the discharging port of the suspension roasting furnace is connected to the feeding port of the cyclone separator through a pipeline; A burner is provided at the bottom of the suspension heating roasting furnace, which is connected to gas and air; The lower discharge port of the cyclone separator is connected to the feeding port of the suspension sulfidation roaster, the discharging port of the suspension sulfidation roaster is connected to the feeding port of the cooler, the discharging port of the cooler is connected to the feeding port of the ball mill, and the discharging port of the ball mill is connected to the flotation machine; A plurality of air inlets are provided at the bottom of the suspension sulfidation roaster, which are respectively communicated with nitrogen and gas sources; The screw feeder II is connected to the feeding port of the suspension sulfidation roaster, and the sulfiding agent is fed into the suspension sulfidation roaster from the screw feeder II.

5. A method for treating zinc smelting slag according to claim 4, characterized in that, The side exhaust hole of the cooler is connected to the air inlet of the suspension heating roasting furnace; a nitrogen inlet is provided at the bottom of the cooler for cooling.

6. The zinc smelting slag treatment method according to claim 4, characterized in that, The upper gas outlet of the cyclone separator is connected and communicated with the side air inlet of the cyclone preheater; thermocouple temperature measuring devices and pressure sensor devices are provided inside the cyclone preheater, the suspension heating roasting furnace, the suspension sulfidation roaster, the cooler and the cyclone separator, and the temperatures of each temperature measuring point and the pressures of each pressure measuring point are monitored in real time by a computer.

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