System and method for recovering valuable metals through zinc pyrometallurgy

Abstract

The invention discloses a system and a method for recovering valuable metals through zinc pyrometallurgy. A system for recovering valuable metal through zinc pyrometallurgy comprises a smelting device, the smelting device is provided with an oxidation smelting area and a reduction smelting area, the bottom of the oxidation smelting area is communicated with the bottom of the reduction smelting area, zinc concentrate is smelted in the oxidation smelting area and subjected to oxidation desulfurization, and slag generated through smelting in the oxidation smelting area flows into the reduction smelting area to be reduced; the oxidation smelting area is provided with a first smoke outlet and a first metal discharging opening, and the reduction smelting area is provided with a second smoke outlet, a second metal discharging opening and a slag discharging opening. The system further comprises a first processing unit and a second processing unit. The first treatment unit is connected with the first smoke outlet and used for recycling valuable metal in smoke exhausted from the oxidation smelting area, and the second treatment unit is connected with the second smoke outlet and used for recycling valuable metal in smoke exhausted from the reduction smelting area. According to the method, short-process zinc pyrometallurgy can be achieved, the material preparation process is simplified, and the metal recovery rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of metal smelting, and in particular relates to a system and method for recovering valuable metals by pyrometallurgical zinc smelting. Background Art

[0002] Zinc smelting is mainly divided into pyrometallurgy and hydrometallurgy. Hydrometallurgy has a long technical process, and the leaching slag and iron slag produced are hazardous wastes that need to be harmlessly treated. The energy consumption is high and it brings new pollution. Pyrometallurgy is mainly divided into blast furnace zinc smelting, vertical tank zinc smelting and electric furnace zinc smelting. The pyrometallurgy technology in related technologies has a complex material preparation process and a low metal recovery rate. Summary of the invention

[0003] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0004] The inventors realized that blast furnace zinc smelting can only process lead-zinc mixed ore with a certain lead-zinc ratio. The raw materials must be sintered before entering the furnace. The final slag of the blast furnace contains 5% to 7% zinc, the slag contains high zinc, and the recovery rate of valuable metals such as zinc is low; in vertical tank zinc smelting, the zinc concentrate must be subjected to desulfurization and molding treatments such as roasting and pelletizing before entering the furnace, which has high requirements on the raw material composition and a complicated material preparation process. The final slag contains 5% to 10% zinc, and the recovery rates of valuable metals such as zinc, copper, gold and silver are all low; in electric furnace zinc smelting, the zinc concentrate needs to be subjected to desulfurization treatments such as roasting before entering the furnace. After entering the furnace, the atmosphere and temperature in the furnace need to be controlled during the smelting process. The bed capacity and reduction efficiency are low, the final slag contains 3% to 6% zinc, and copper is enriched in bottom iron recovery, and the recovery rate is low. In addition, the single series production capacity of pyrometallurgy is small and cannot meet the requirements of modern large-scale industrial production.

[0005] The inventors also realized that the wet smelting is mainly to leach zinc oxides through the sulfuric acid system. Before the zinc concentrate is leached, it must be subjected to desulfurization treatment such as roasting to obtain a zinc sulfate solution, which is purified by liquid purification and electrolytic deposition to obtain a cathode zinc sheet, and then zinc 99.995% zinc ingots are obtained by zinc smelting. However, the process has many procedures, complex processes, huge investment, and high energy consumption. The DC power consumption of a ton of zinc in a single electrolytic process reaches 3000kWh. More importantly, the wet process produces a large amount of leaching slag, iron slag, etc., with an output rate of more than 50%, and they are all hazardous wastes, which need to be harmlessly treated, resulting in a large amount of energy consumption and bringing new pollution. The wet process is divided into conventional leaching process and hot acid leaching process, among which conventional leaching process is the main one, accounting for 70% to 80% of the total production capacity. The recovery rate of copper is generally 30% to 40%, and the best level can only reach 50%. The recovery rates of gold and silver are similar, both about 60%, and the recovery rate of valuable metals is low.

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, an embodiment of the present invention provides a system for recovering valuable metals by pyrometallurgical zinc smelting, which can realize short-process pyrometallurgical zinc smelting, simplify the material preparation process, and improve the metal recovery rate.

[0008] The embodiment of the present invention also provides a method for recovering valuable metals by pyrometallurgical zinc smelting.

[0009] The system for recovering valuable metals by pyrometallurgical zinc smelting according to the embodiment of the present invention comprises a smelting device;

[0010] The smelting device comprises an oxidation smelting zone and a reduction smelting zone, the oxidation smelting zone and the reduction smelting zone are connected at the bottom, the zinc concentrate is smelted and oxidatively desulfurized in the oxidation smelting zone, and the slag produced by smelting in the oxidation smelting zone flows into the reduction smelting zone for reduction;

[0011] The oxidation smelting zone has a first smoke exhaust port and a first metal exhaust port, and the reduction smelting zone has a second smoke exhaust port, a second metal exhaust port and a slag exhaust port;

[0012] The pyrometallurgical zinc smelting and valuable metal recovery system also includes:

[0013] a first processing unit and a second processing unit;

[0014] The first processing unit is connected to the first smoke exhaust port, and the first processing unit is used to recover the valuable metals in the smoke exhausted from the oxidation smelting zone. The second processing unit is connected to the second smoke exhaust port, and the second processing unit is used to recover the valuable metals in the smoke exhausted from the reduction smelting zone.

[0015] The system for recovering valuable metals by pyrometallurgical zinc smelting according to the embodiment of the present invention can realize short-process pyrometallurgical zinc smelting, simplify the material preparation process, and improve the metal recovery rate.

[0016] In some embodiments, the oxidation smelting zone has a first operating condition and a second operating condition;

[0017] Under the first working condition, the temperature in the oxidation smelting zone is 1100°C to 1300°C, and the oxygen-to-material ratio in the oxidation smelting zone is 100Nm 3 / t to 250Nm 3 / t;

[0018] Under the second working condition, the temperature in the oxidation smelting zone is 1350°C to 1550°C, and the oxygen-to-material ratio in the oxidation smelting zone is 300Nm 3 / t to 500Nm 3 / t.

[0019] In some embodiments, the oxidizing smelting zone further comprises a first lance, the oxidizing smelting zone has a first nozzle, and the first lance is connected to the first nozzle to inject oxygen into the oxidizing smelting zone;

[0020] And / or, the oxidation smelting zone further has a first feed inlet, and the first feed inlet is used to feed zinc concentrate and flux into the oxidation smelting zone;

[0021] And / or, the first metal discharge port is a siphon port.

[0022] In some embodiments, the reduction and smelting zone includes an electric thermal reduction section and a jet blowing section. The slag flowing into the reduction and smelting zone passes through the electric thermal reduction section and the jet blowing section in sequence for reduction. The second metal discharge port and the slag discharge port are arranged close to the jet blowing section.

[0023] In some embodiments, it also includes an electrode and a second spray gun, the electrode is arranged in the electrothermal reduction section, the reduction and smelting zone also has a second feed port and a second nozzle, the second feed port is used to feed the reducing agent into the electrothermal reduction section, the second nozzle is opened on the side wall of the jet blowing section, and the second spray gun is connected to the second nozzle to feed the carbonaceous reducing agent and oxygen into the jet blowing section.

[0024] In some embodiments, the amount of oxygen injected into the jet injection section through the second injection gun is 0.1 to 0.5 of the total amount of oxygen required for complete combustion of the carbonaceous reductant.

[0025] In some embodiments, the electrothermal reduction section and the jet blowing section are arranged along a first direction, and a length a of the electrothermal reduction section in the first direction and a length b of the jet blowing section in the first direction satisfy: a>2b;

[0026] And / or, the heat supplement ratio between the electrothermal reduction section and the jet blowing section is 2:1 to 5:1;

[0027] And / or, the volume ratio of CO to CO2 in the reduction smelting zone is 20:1 to 35:1.

[0028] In some embodiments, the first processing unit includes a dust collecting device, and the dust collecting device is used to recover high-cadmium smoke in the smoke exhausted from the oxidation smelting zone;

[0029] And / or, the second processing unit comprises a condensing device and a distillation device, the condensing device is used to condense the flue gas discharged from the reduction smelting zone to recover the crude zinc, and the distillation device is used to refine the crude zinc to separate the valuable metals.

[0030] In some embodiments, the distillation device has a first distillation temperature and a second distillation temperature, the first distillation temperature is 900°C to 950°C to recover metallic lead in crude zinc, and the second distillation temperature is 500°C to 600°C to recover metallic cadmium in crude zinc.

[0031] The method for recovering valuable metals by pyrometallurgical zinc smelting according to the embodiment of the present invention adopts the above-mentioned system for recovering valuable metals by pyrometallurgical zinc smelting to carry out pyrometallurgical zinc smelting and recover valuable metals, and specifically comprises the following steps:

[0032] The zinc concentrate, flux and oxygen are transported into the oxidation smelting zone for melting and oxidation desulfurization to obtain copper matte and sulfur-containing slag, and the copper matte is discharged through the first metal discharge port;

[0033] The temperature and oxygen-to-material ratio in the oxidation smelting zone are increased, the sulfur-containing slag is further oxidized and desulfurized in the oxidation smelting zone, and high-cadmium smoke and low-sulfur slag are obtained, the low-sulfur slag flows into the reduction smelting zone, and the high-cadmium smoke is discharged through the first smoke exhaust port and collected by the first processing unit;

[0034] A reducing agent is added to the reduction smelting zone to reduce the low-sulfur slag to obtain zinc vapor and molten iron carrying valuable metals. The zinc vapor is discharged from the second smoke exhaust port and refined and separated into valuable metals by the second processing unit, and the molten iron is discharged from the second metal discharge port. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of a system for recovering valuable metals by pyrometallurgical zinc smelting according to an embodiment of the present invention.

[0036] Figure 2 It is a schematic structural diagram of a smelting device according to an embodiment of the present invention.

[0037] Figure 3 yes Figure 2 Schematic diagram of the structure in the A direction.

[0038] Reference numerals:

[0039] 1. Smelting device; 11. Oxidation smelting zone; 111. First feed port; 12. Reduction smelting zone; 121. Electrothermal reduction section; 122. Jet blowing section; 123. Second feed port; 124. Electrode; 13. First metal discharge port; 14. First smoke exhaust port; 15. First nozzle; 16. Second metal discharge port; 17. Slag discharge port; 18. Second smoke exhaust port; 19. Second nozzle;

[0040] 2. A first processing unit;

[0041] 3. Second processing unit; 31. Condensation device; 32. Distillation device;

[0042] 41. Reducing agent feeding device; 42. Electrode lifting device; 43. Mixing device; 44. Loading device;

[0043] 51. Zinc concentrate; 52. Flux. DETAILED DESCRIPTION

[0044] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0045] The following combination Figure 1-Figure 3 The system and method for recovering valuable metals by pyrometallurgical zinc smelting according to the embodiment of the present invention are described in detail.

[0046] like Figure 1-Figure 3 As shown, the system for recovering valuable metals by pyrometallurgical zinc smelting according to an embodiment of the present invention comprises a smelting device 1, wherein the smelting device 1 comprises an oxidation smelting zone 11 and a reduction smelting zone 12, wherein the bottoms of the oxidation smelting zone 11 and the reduction smelting zone 12 are connected, and the zinc concentrate 51 is smelted and oxidatively desulfurized in the oxidation smelting zone 11, and the slag generated by smelting in the oxidation smelting zone 11 flows into the reduction smelting zone 12 for reduction, and the oxidation smelting zone 11 comprises a first smoke exhaust port 14 and a first metal exhaust port 13, and the reduction smelting zone 12 comprises a second smoke exhaust port 18, a second metal exhaust port 16 and a slag exhaust port 17.

[0047] The smelting device 1 provided in the embodiment of the present invention can realize short-process pyrometallurgical zinc smelting through oxidative desulfurization in the oxidative smelting zone 11 and high-temperature reduction in the reductive smelting zone 12. The zinc concentrate 51 does not need complicated preparation and processing. The zinc concentrate 51, flux 52 and oxygen are directly sent into the oxidative smelting zone 11 for oxidative desulfurization, avoiding the treatment of the zinc concentrate 51 before entering the furnace. In the oxidative smelting zone 11 in the embodiment of the present invention, the zinc concentrate 51 can be smelted into copper matte under the condition of low temperature and low oxygen potential, thereby capturing most of the precious metals such as copper, gold, and silver. The copper matte is deposited at the bottom of the molten pool and discharged from the first metal discharge port 13, and then fully desulfurized under the condition of high temperature and high oxygen potential to generate smoke containing cadmium and lead, which is discharged from the first smoke exhaust port 14 along with the flue gas. The slag from the oxidation smelting zone 11 flows into the reduction smelting zone 12. The slag contains zinc and remaining valuable metals. The slag can be reduced at high temperature in the reduction smelting zone 12 to produce molten iron. The remaining small amount of valuable metals such as copper, gold, silver, etc. are recovered in the molten iron. The molten iron is discharged from the second metal discharge port 16. The remaining lead and cadmium as well as indium, germanium, etc. are reduced to form steam and are discharged from the second smoke exhaust port 18 together with the zinc steam.

[0048] The pyrometallurgical zinc smelting and valuable metal recovery system also includes a first processing unit 2 and a second processing unit 3; the first processing unit 2 is connected to the first smoke exhaust port 14, and the first processing unit 2 is used to recover the valuable metals in the smoke discharged from the oxidation smelting zone 11, and the second processing unit 3 is connected to the second smoke exhaust port 18, and the second processing unit 3 is used to recover the valuable metals in the smoke discharged from the reduction smelting zone 12.

[0049] That is to say, the flue gas and smoke generated in the oxidation smelting zone 11 are discharged from the first smoke exhaust port 14 and enter the first processing unit 2, thereby realizing the recovery of smoke containing valuable metals cadmium and lead, and the zinc vapor carrying valuable metals is discharged from the second smoke exhaust port 18 and enters the second processing unit 3, thereby realizing the recovery of zinc and the remaining valuable metals.

[0050] The system for recovering valuable metals by pyrometallurgical zinc smelting according to the embodiment of the present invention can realize short-process pyrometallurgical zinc smelting, simplify the material preparation process, and improve the metal recovery rate.

[0051] In some embodiments, the oxidative smelting zone 11 has a first operating condition and a second operating condition.

[0052] Under the first working condition, the temperature in the oxidation smelting zone is 1100℃ to 1300℃, and the oxygen-to-material ratio in the oxidation smelting zone is 100Nm 3 / t to 250Nm 3 / t.

[0053] Under the second working condition, the temperature in the oxidation smelting zone is 1350℃ to 1550℃, and the oxygen-to-material ratio in the oxidation smelting zone is 300Nm 3 / t to 500Nm 3 / t.

[0054] It should be understood that under the first working condition, the oxidation smelting zone is at low temperature and low oxygen potential, the zinc concentrate is oxidatively desulfurized under the low temperature and low oxygen potential conditions in the oxidation smelting zone, and sulfur-containing high-zinc slag and copper matte that captures most of the precious metals such as copper, gold, silver, etc. are obtained, realizing the recovery of most of the precious metals such as copper, gold, silver, etc. Under the second working condition, the oxidation smelting zone is at high temperature and high oxygen potential conditions, the high-zinc slag can be further desulfurized under the high temperature and high oxygen potential conditions in the oxidation smelting zone, forming low-sulfur high-zinc slag and high-cadmium smoke containing cadmium and lead, realizing the recovery of cadmium and lead.

[0055] Under low temperature and low oxygen potential conditions, the sulfur-containing high-zinc slag formed contains S2% to 5%, the copper matte formed contains Cu10% to 30%, and 70% to 80% of Cu, 80% to 90% of Au and 80% to 90% of Ag are enriched in the copper matte for recovery.

[0056] Under high temperature and high oxygen potential conditions, the low-sulfur, high-zinc slag formed contains S <1%, Zn 40% to 60%, and the high-cadmium smoke formed contains Cd > 12%.

[0057] The oxygen potential of the embodiment of the present invention is expressed as an oxygen-to-material ratio, which is the ratio of the volume of oxygen to the mass of the mineral material.

[0058] Further, under the first working condition, the temperature in the oxidation smelting zone is 1100°C, 1130°C, 1175°C, 1200°C, 1265°C or 1300°C, and the oxygen-to-material ratio in the oxidation smelting zone is 100Nm 3 / t, 120Nm 3 / t, 142Nm 3 / t、155Nm 3 / t, 195Nm 3 / t, 230Nm 3 / t or 250Nm 3 / t.

[0059] Under the second working condition, the temperature in the oxidation smelting zone is 1350°C, 1380°C, 1395°C, 1426°C, 1448°C, 1496°C, 1525°C or 1550°C, and the oxygen-to-material ratio in the oxidation smelting zone is 300Nm 3 / t、320Nm 3 / t、342Nm 3 / t、355Nm 3 / t、395Nm 3 / t、430Nm 3 / t、495Nm 3 / t or 500Nm 3 / t.

[0060] Under two different working conditions, by reasonably controlling the oxygen-to-material ratio at different stages, the stability of the chemical reactions in different sections of the furnace can be guaranteed, and the smelting process can be accurately controlled and optimized, which can reduce energy consumption and costs and improve metal recovery rates.

[0061] In some embodiments, the system for recovering valuable metals by pyrometallurgical zinc smelting further includes a first lance. The oxidation smelting zone 11 has a first nozzle 15 . The first lance is connected to the first nozzle 15 to inject oxygen into the oxidation smelting zone 11 .

[0062] The first lance sprays oxygen or oxygen-enriched air into the oxidation smelting zone 11 to adjust the oxygen-to-material ratio in the oxidation smelting zone 11 to ensure smelting oxidation desulfurization treatment at different stages.

[0063] Optionally, there are multiple first spray guns, which are arranged side by side and spaced apart. The gas sprayed by the first spray gun can also fully stir the slag, thereby promoting a full chemical reaction in the oxidation smelting zone 11 .

[0064] Furthermore, the first lance is vertically positioned higher than the first metal discharge port 13 and the connecting port between the oxidation smelting zone 11 and the reduction smelting zone 12, thereby avoiding causing a large disturbance to the copper matte deposited at the bottom of the oxidation smelting zone 11 and facilitating the smooth discharge of the copper matte.

[0065] In some embodiments, the oxidation smelting zone 11 further has a first feed port 111, and the first feed port 111 is used to feed the zinc concentrate 51 and the flux 52 into the oxidation smelting zone 11. After the zinc concentrate 51 and the flux 52 are evenly mixed by the mixing device 43, they are transported into the oxidation smelting zone 11 by a feeding device such as a conveyor to complete the feeding. The mixing device 43 can be a stirring drum, and the zinc concentrate 51 and the flux 52 can be mixed by stirring after being added to the stirring drum, which reduces the difficulty of preparing the materials and does not require other pre-furnace treatments.

[0066] The flux 52 may be quartz sand, and the ratio of the zinc concentrate 51 to the flux 52 is 5:1 to 20:1.

[0067] In some embodiments, the first metal discharge port 13 is a siphon port. Under low temperature and low oxygen potential conditions, the copper matte formed in the oxidation smelting zone 11 is deposited to the bottom of the molten pool and discharged through the siphon port, thereby improving the quality of the copper matte, optimizing the smelting process, and preventing slag from flowing out.

[0068] In some embodiments, the reduction smelting zone 12 includes an electric thermal reduction section 121 and a jet blowing section 122. The slag flowing into the reduction smelting zone 12 passes through the electric thermal reduction section 121 and the jet blowing section 122 in turn for reduction. The second metal discharge port 16 and the slag discharge port 17 are arranged close to the jet blowing section 122.

[0069] In the embodiment of the present invention, the two-stage reduction of the electrothermal reduction section 121 and the jet blowing section 122 is used to achieve deep reduction of the slag. The slag flowing from the oxidation smelting zone 11 into the reduction smelting zone 12 is first reduced by the electrothermal reduction section 121, and then deeply reduced by the jet blowing section 122. The remaining small amount of valuable metals such as copper, gold, and silver are discharged from the second metal discharge port 16 along with the molten pig iron, and the slag is discharged from the slag discharge port 17. The remaining lead and cadmium as well as valuable metals such as indium and germanium are discharged from the second smoke exhaust port 18 along with the high zinc vapor.

[0070] The embodiment of the present invention improves the smelting efficiency and metal recovery rate by segmenting the reduction smelting zone 12 and performing reduction treatment on the slag in sequence, and enables the reduction treatment process to be more effectively controlled, thereby realizing a short-process pyrometallurgical zinc smelting process.

[0071] Furthermore, the reduction smelting zone 12 also includes an electrode 124 and a second spray gun, the electrode 124 is arranged in the electric thermal reduction section 121, and the reduction smelting zone 12 also has a second feed port 123 and a second nozzle 19. The second feed port 123 is used to feed the reducing agent into the electric thermal reduction section 121, and the reducing agent is quantitatively transported into the electric thermal reduction section 121 through a reducing agent feeding device 41 connected to the second feed port 123. The second nozzle 19 is opened on the side wall of the jet blowing section 122, and the second spray gun is connected to the second nozzle 19 to feed the carbonaceous reducing agent and oxygen into the jet blowing section 122.

[0072] The electric thermal reduction section 121 uses an electrode 124 to supplement heat, and the reducing agent is added into the electric thermal reduction section 121 through the second feed port 123. The second spray gun is used to feed the carbonaceous reducing agent and oxygen into the jet blowing section 122, which can provide heat for deep reduction on the one hand and provide reducing agent for the reduction process on the other hand.

[0073] In the embodiment of the present invention, the amount of oxygen injected into the jet injection section 122 by the second spray gun is 0.1 to 0.5 of the total amount of oxygen required for complete combustion of the carbonaceous reducing agent. The carbonaceous reducing agent is partially burned to supplement heat, and the unburned part can be used as a reducing agent to perform high-temperature deep reduction treatment on the slag, thereby improving the efficiency and effect of smelting.

[0074] The electrode 124 is a graphite electrode 124 , and is also provided with an electrode lifting device 42 for driving the electrode 124 to rise and fall in a vertical direction.

[0075] Optionally, the amount of oxygen sprayed into the jet blowing section 122 by the second spray gun is 0.1, 0.2, 0.33, 0.36, 0.41, 0.44, 0.485 or 0.5 of the total amount of oxygen required for complete combustion of the carbonaceous reducing agent. When the amount of oxygen sprayed into the jet blowing section 122 by the second spray gun is too little and less than 0.1 times the total amount of oxygen required for complete combustion of the carbonaceous reducing agent, it is difficult to achieve an ideal heat supplement effect, and the deep reduction effect of the jet blowing section 122 cannot be exerted. When the amount of oxygen sprayed into the jet blowing section 122 by the second spray gun is too much and greater than 0.5 times the total amount of oxygen required for complete combustion of the carbonaceous reducing agent, it will cause heat waste and increase heat consumption, and at the same time will cause a reduction in the amount of reducing agent, which is not conducive to deep reduction reaction.

[0076] Furthermore, the heat supplement ratio of the electrothermal reduction section 121 and the jet blowing section 122 is 2:1 to 5:1, for example, the heat supplement ratio of the electrothermal reduction section 121 and the jet blowing section 122 is 2:1, 3:1, 3.4:1, 4.2:1, 4.6:1 or 5:1. By adjusting the heat supplement ratio of the electrothermal reduction section 121 and the jet blowing section 122, the temperature and degree of reduction treatment of the slag in the electrothermal reduction section 121 and the jet blowing section 122 can be optimized, the reduction process can be optimized, and the smelting effect can be improved.

[0077] Furthermore, the volume ratio of CO to CO2 in the reduction smelting zone 12 is 20: 1 to 35: 1. The volume ratio of CO to CO2 in the reduction smelting zone 12 is controlled within a reasonable range, thereby optimizing the reduction process, ensuring production efficiency and improving product quality, and helping to improve the direct recovery rate and recovery rate of metals.

[0078] In some embodiments, the electrothermal reduction section 121 and the jet blowing section 122 are arranged along the first direction, and the length a of the electrothermal reduction section 121 in the first direction and the length b of the jet blowing section 122 in the first direction satisfy: a>2b.

[0079] In the embodiment of the present invention, by further optimizing the space of the reduction smelting zone 12, the reduction treatment effect of the slag in this area can be improved, so that the slag can be fully and deeply reduced, thereby obtaining high-quality products.

[0080] The cross section of the reduction smelting zone 12 is approximately rectangular, and the first direction is the length direction of the cross section of the reduction smelting zone 12 .

[0081] For example, the length of the reduction smelting zone 12 in the first direction is L, the length a of the electrothermal reduction section 121 in the first direction is 3 / 4L, and the length b of the jet blowing section 122 in the first direction is 1 / 4L.

[0082] Alternatively, the length a of the electrothermal reduction section 121 in the first direction is 5 / 7L, and the length b of the jet blowing section 122 in the first direction is 2 / 7L.

[0083] When a≤2b, it is easy to cause poor reduction treatment effect of the slag in the reduction smelting zone 12, the reduction treatment time of the slag in the electric thermal reduction section 121 is relatively too short, and the reduction treatment time in the jet blowing section 122 is relatively too long, which affects the smelting effect of the slag and the quality of the product.

[0084] In some embodiments, the first processing unit 2 includes a dust collecting device, which is used to recover high-cadmium dust in the flue gas discharged from the oxidation smelting zone 11.

[0085] After the high-cadmium dust and flue gas pass through the dust collecting device, the high-cadmium dust and the flue gas containing sulfides are separated, and the flue gas is discharged into the atmosphere after harmless treatment. The valuable metals such as cadmium and lead in the high-cadmium dust can be recovered.

[0086] Furthermore, the second processing unit 3 comprises a condensing device 31 and a distilling device 32. The condensing device 31 is used to condense the flue gas discharged from the reduction smelting zone 12 to recover the crude zinc, and the distilling device 32 is used to refine the crude zinc to separate the valuable metals.

[0087] The high-zinc steam produces crude zinc after passing through the condensation device 31, and the crude zinc is refined through the distillation device 32 to obtain zinc, lead and cadmium.

[0088] The distillation device 32 has a first distillation temperature and a second distillation temperature. The first distillation temperature is 900° C. to 950° C. to recover metallic lead in crude zinc, and the second distillation temperature is 500° C. to 600° C. to recover metallic cadmium in crude zinc.

[0089] Valuable metals such as cadmium, lead, indium, and germanium can be recovered through distillation. Metallic lead in crude zinc is recovered at the first distillation temperature, and metallic cadmium in crude zinc is recovered at the second distillation temperature.

[0090] For example, the first distillation temperature is 900° C., 910° C., 915° C., 923° C., 936° C., 947° C. or 950° C. The second distillation temperature is 500° C., 510° C., 517° C., 522° C., 536° C., 539° C. or 500° C. By reasonably controlling the distillation temperatures at different stages, refined zinc and other valuable metals can be obtained.

[0091] The Zn content of the refined zinc in the embodiment of the present invention is greater than 99.995%.

[0092] At the same time, the recovery rate of zinc in the embodiment of the present invention can reach 97% to 98%, the recovery rate of lead can reach 97% to 98%, the recovery rate of copper can reach 90% to 95%, the recovery rate of cadmium can reach 90% to 95%, the recovery rate of gold can reach 90% to 95%, the recovery rate of silver can reach 90% to 95%, the recovery rate of indium can reach 90% to 95%, and the recovery rate of germanium can reach 90% to 95%.

[0093] The method for recovering valuable metals by pyrometallurgical zinc smelting according to the embodiment of the present invention adopts the above-mentioned system for recovering valuable metals by pyrometallurgical zinc smelting to carry out pyrometallurgical zinc smelting and recover valuable metals, and specifically comprises the following steps:

[0094] S101, zinc concentrate 51, flux 52 and oxygen are transported into oxidation smelting zone 11 for melting and oxidation desulfurization treatment to obtain copper matte and sulfur-containing slag, and the copper matte is discharged through the first metal discharge port 13. The copper matte contains 10% to 30% Cu, 70% to 80% Cu, 80% to 90% Au and 80% to 90% Ag enriched in the copper matte can be recovered, and the sulfur-containing slag contains 2% to 5% S.

[0095] In this step, oxidative desulfurization is carried out under low temperature and low oxygen potential conditions, that is, the reaction treatment is carried out under the first working condition in the above embodiment.

[0096] S102, increasing the temperature and oxygen-to-material ratio in the oxidation smelting zone 11, further oxidizing and desulfurizing the sulfur-containing slag in the oxidation smelting zone 11, and obtaining high-cadmium smoke and low-sulfur slag, the low-sulfur slag flows into the reduction smelting zone 12, and the high-cadmium smoke is discharged through the first smoke exhaust port 14 and collected by the first processing unit 2.

[0097] Among them, high-cadmium smoke contains Cd>12%, low-sulfur slag contains S<1%, and Zn40% to 60%.

[0098] In this step, high temperature and high oxygen potential conditions are used for further desulfurization, that is, the reaction treatment is carried out under the second working condition in the above embodiment.

[0099] The crude zinc in the embodiment of the present invention is refined by the crude zinc distillation device 32 , and the crude zinc is separated and recovered from cadmium and lead by controlling the temperature in the distillation device 32 .

[0100] The raw materials in the embodiment of the present invention have strong adaptability and do not require complicated material preparation. The materials can be directly put into the furnace after mixing. The mixed materials are oxidized and desulfurized under low temperature and low oxygen potential conditions in the oxidation smelting zone 11 to form copper matte, which captures valuable metals such as copper, gold, and silver; then the temperature and oxygen potential of the oxidation smelting zone 11 are increased to achieve deep desulfurization, and high cadmium smoke is formed to recover valuable metals such as cadmium and lead.

[0101] S103, adding a reducing agent to the reduction smelting zone 12 to reduce the low-sulfur slag to obtain zinc vapor and molten iron carrying valuable metals. The zinc vapor is discharged from the second smoke exhaust port 18 and refined and separated into valuable metals by the second processing unit 3, and the molten iron is discharged from the second metal discharge port 16.

[0102] High-zinc slag (i.e., low-sulfur slag) is reduced in the reduction smelting zone 12. By controlling the volume ratio of CO to CO2, the valuable metals in the molten pool are reduced. The zinc in the slag is reduced to form zinc vapor, and valuable metals such as cadmium, lead, indium, and germanium are volatilized into the zinc vapor and discharged from the second smoke exhaust port 18 of the reduction smelting zone 12. The zinc vapor is condensed by the condensing device 31 to produce crude zinc. The iron element in the high-zinc slag is reduced to form pig iron, and the remaining valuable metals such as copper, gold, and silver are enriched in the pig iron and recovered.

[0103] In the reduction process of the embodiment of the present invention, the volume ratio of CO to CO2 is controlled to generate pig iron, and the remaining valuable metals such as copper, gold, and silver are captured and recovered. At the same time, valuable metals such as cadmium, lead, indium, and germanium are enriched in zinc vapor, and crude zinc is obtained by condensing the zinc vapor. The crude zinc is distilled to recover the remaining lead and cadmium, and high-boiling-point metals such as indium and germanium are enriched in hard zinc for further recovery.

[0104] By using the system and method of the embodiments of the present invention, the recovery rate of zinc can reach 97% to 98%, the recovery rate of lead can reach 97% to 98%, the recovery rate of copper can reach 90% to 95%, the recovery rate of cadmium can reach 90% to 95%, the recovery rate of gold can reach 90% to 95%, the recovery rate of silver can reach 90% to 95%, the recovery rate of indium can reach 90% to 95%, and the recovery rate of germanium can reach 90% to 95%.

[0105] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0106] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0107] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0108] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0109] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0110] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A system for recovering valuable metals by pyrometallurgical zinc smelting, characterized in that: including a smelting unit; The smelting device comprises an oxidation smelting zone and a reduction smelting zone, the oxidation smelting zone and the reduction smelting zone are connected at the bottom, the zinc concentrate is smelted and oxidatively desulfurized in the oxidation smelting zone, and the slag produced by smelting in the oxidation smelting zone flows into the reduction smelting zone for reduction; The oxidation smelting zone has a first smoke exhaust port and a first metal exhaust port, and the reduction smelting zone has a second smoke exhaust port, a second metal exhaust port and a slag exhaust port; The pyrometallurgical zinc smelting and valuable metal recovery system also includes: a first processing unit and a second processing unit; The first processing unit is connected to the first smoke exhaust port, and the first processing unit is used to recover the valuable metals in the smoke exhausted from the oxidation smelting zone. The second processing unit is connected to the second smoke exhaust port, and the second processing unit is used to recover the valuable metals in the smoke exhausted from the reduction smelting zone.

2. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 1, characterized in that: The oxidation smelting zone has a first operating condition and a second operating condition; Under the first working condition, the temperature in the oxidation smelting zone is 1100°C to 1300°C, and the oxygen-to-material ratio in the oxidation smelting zone is 100Nm 3 / t to 250Nm 3 / t; Under the second working condition, the temperature in the oxidation smelting zone is 1350°C to 1550°C, and the oxygen-to-material ratio in the oxidation smelting zone is 300Nm 3 / t to 500Nm 3 / t.

3. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 1, characterized in that: It also includes a first lance, the oxidation smelting zone has a first nozzle, and the first lance is connected to the first nozzle to inject oxygen into the oxidation smelting zone; And / or, the oxidation smelting zone further has a first feed inlet, and the first feed inlet is used to feed zinc concentrate and flux into the oxidation smelting zone; And / or, the first metal discharge port is a siphon port.

4. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 1, characterized in that: The reduction smelting zone includes an electric thermal reduction section and a jet blowing section. The slag flowing into the reduction smelting zone passes through the electric thermal reduction section and the jet blowing section in sequence for reduction. The second metal discharge port and the slag discharge port are arranged close to the jet blowing section.

5. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 4, characterized in that: It also includes an electrode and a second spray gun, the electrode is arranged in the electrothermal reduction section, the reduction and smelting zone also has a second feed port and a second nozzle, the second feed port is used to feed the reducing agent into the electrothermal reduction section, the second nozzle is opened on the side wall of the jet blowing section, and the second spray gun is connected to the second nozzle to feed the carbonaceous reducing agent and oxygen into the jet blowing section.

6. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 5, characterized in that: The amount of oxygen injected into the jet injection section through the second injection gun is 0.1 to 0.5 of the total amount of oxygen required for complete combustion of the carbonaceous reducing agent.

7. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 5 or 6, characterized in that: The electrothermal reduction section and the jet blowing section are arranged along a first direction, and a length a of the electrothermal reduction section in the first direction and a length b of the jet blowing section in the first direction satisfy: a>2b; And / or, the heat supplement ratio between the electrothermal reduction section and the jet blowing section is 2:1 to 5:1; And / or, the volume ratio of CO to CO2 in the reduction smelting zone is 20:1 to 35:

1.

8. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 1, characterized in that: The first processing unit includes a dust collecting device, which is used to recover high-cadmium smoke in the smoke discharged from the oxidation smelting zone; And / or, the second processing unit comprises a condensing device and a distillation device, the condensing device is used to condense the flue gas discharged from the reduction smelting zone to recover the crude zinc, and the distillation device is used to refine the crude zinc to separate the valuable metals.

9. The system for recovering valuable metals by pyrometallurgical zinc smelting according to claim 8, characterized in that: The distillation device has a first distillation temperature and a second distillation temperature, wherein the first distillation temperature is 900° C. to 950° C. to recover metallic lead in crude zinc, and the second distillation temperature is 500° C. to 600° C. to recover metallic cadmium in crude zinc.

10. A method for recovering valuable metals by pyrometallurgical zinc smelting, characterized in that: The pyrometallurgical zinc smelting and valuable metal recovery system according to any one of claims 1 to 9 is used to carry out pyrometallurgical zinc smelting and valuable metal recovery, specifically comprising the following steps: The zinc concentrate, flux and oxygen are transported into the oxidation smelting zone for melting and oxidation desulfurization to obtain copper matte and sulfur-containing slag, and the copper matte is discharged through the first metal discharge port; The temperature and oxygen-to-material ratio in the oxidation smelting zone are increased, the sulfur-containing slag is further oxidized and desulfurized in the oxidation smelting zone, and high-cadmium smoke and low-sulfur slag are obtained, the low-sulfur slag flows into the reduction smelting zone, and the high-cadmium smoke is discharged through the first smoke exhaust port and collected by the first processing unit; A reducing agent is added to the reduction smelting zone to reduce the low-sulfur slag to obtain zinc vapor and molten iron carrying valuable metals. The zinc vapor is discharged from the second smoke exhaust port and refined and separated into valuable metals by the second processing unit, and the molten iron is discharged from the second metal discharge port.

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