Device and method for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag

Abstract

The application provides a device and method for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag. The device comprises a first smelting unit, a second smelting unit and a negative pressure unit. The first smelting unit comprises a first smelting furnace, a silicon slag forming agent supply unit, a first reducing agent supply unit and a first flue gas treatment unit. The second smelting unit comprises a second smelting furnace, a calcium slag forming agent supply unit, a second reducing agent supply unit and a second flue gas treatment unit. By using the device, copper, lead, zinc, antimony, gold, silver, iron and other non-ferrous and black elements in copper smelting slag can be recovered, and harmful elements such as arsenic in the slag can be deeply removed. The arsenic is enriched, and the comprehensive recovery of non-ferrous and black elements in copper slag is realized. The generated tail slag is similar to ironmaking tail slag and is harmless tail slag, which can be directly built into materials. In short, the device has multiple advantages of high efficiency, short process, low energy consumption, low cost, small land occupation, full recovery of valuable metal elements and environmental friendliness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper smelting slag treatment, in particular to a device and method for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag. BACKGROUND

[0002] In the traditional copper smelting process, 2.2-3 times the amount of copper slag is produced, and the copper content in the slag is about 1-5%. In addition to valuable elements such as copper, zinc, lead, antimony, gold, silver, and iron, the zinc content in the copper slag produced by some enterprises is 2-5%. The existing copper slag treatment process mainly includes ore dressing and electric furnace depletion processes.

[0003] The ore dressing process of the slag is to select the slag concentrate to recover copper by slow cooling, crushing, grinding, and flotation processes. The copper content in the slag concentrate is usually 18-23%, and the tailings contain less than 0.3% copper. Secondly, the iron concentrate is selected from the slag concentrate. However, this process has a long process flow, a large area, and occupies about 1 / 4 of the area of the copper smelting plant. Moreover, it is difficult to recover valuable metals such as zinc and lead during the copper recovery process, and part of the zinc is recovered into the iron concentrate during the iron selection process, resulting in a high zinc content in the iron concentrate, which is difficult to use for blast furnace ironmaking, causing the problem of low value of the iron concentrate. The traditional electric furnace depletion process has limitations, resulting in high copper content (>0.6%) in the tailings, and the inability to recover valuable metals such as lead and zinc. The tailings containing 30-45% iron are difficult to recover the iron resources, resulting in the loss of iron resources. Some existing technologies also disclose some copper slag treatment processes, but they all have obvious defects, such as:

[0004] A method for treating copper slag is disclosed in Chinese patent application No. 201910053195.9. However, in the process of recovering copper, a large amount of iron enters the copper matte, which needs to be crushed, finely ground, and ore-dressed to obtain high-grade copper products and iron powder. However, the iron powder obtained by ore dressing contains a high amount of copper (>5%), and copper is a harmful impurity element for some steel grades, which causes cracking during the hot working process of steel, so the iron powder with too high copper content is difficult to use for steel smelting.

[0005] A method for iron recovery by inert gas injection smelting reduction is disclosed in Chinese patent application No. 200910163234.7. This method avoids heat loss, but only considers the recovery of iron and does not consider the recovery and utilization of precious metals and copper. Moreover, it does not consider the impurities present in the iron.

[0006] A method for recovering copper and iron by first oxidizing and desulfurizing hot copper slag and then spraying a reducing agent such as natural gas is disclosed in Chinese Patent No. 201210364451.4. This technology can be used for copper smelting slag obtained by smelting high-quality copper concentrate, but most of the copper smelting slag contains elements such as lead, zinc and arsenic, which exist in the form of oxides in the copper slag. During the natural gas reduction process, most of the zinc and part of the lead and arsenic elements can be reduced and volatilized, but part of the lead and other impurity elements will enter the alloy with copper, resulting in high impurity content in the alloy and affecting product quality.

[0007] A method for directly smelting copper-containing antibacterial stainless steel by reducing molten iron with copper slag is disclosed in Chinese Patent No. 201410345197.2. The method first oxidizes and desulfurizes, and then reduces to obtain copper-containing molten iron for stainless steel smelting, but this scheme fails to solve the problem of the distribution of lead, arsenic and other elements in the slag in the alloy.

[0008] A method for smelting copper-containing cast iron by reducing molten iron after copper slag is separated by sedimentation is disclosed in Chinese Patent No. 201910432636.6. The method recovers copper and precious metals by sedimentation, and then further smelts iron to obtain copper-containing molten iron. However, in the implementation process of this technology, valuable metals such as zinc and lead are not recovered, and the recovery rate of copper and precious metals is low, resulting in too high copper content in the copper-containing pig iron.

[0009] A process for treating copper slag in a CR furnace is proposed in Chinese Patent No. 201711433274.X by Enfi, China, which recovers valuable metals such as copper and zinc in the slag, but this technology has the problem of low utilization rate of pyrite and other sulfidation agents in practice, and the addition of auxiliary materials such as pyrite is to use pyrite to drive the sedimentation of copper and zinc in the slag, which fails to make the copper and zinc particles in the slag sedimentate by themselves, and the grade of the copper and zinc produced is low (15% to 35%), which causes problems such as large processing capacity, low grade and high energy consumption in the subsequent smelting process of copper and zinc. Moreover, this process also has problems such as high sulfur content in the flue gas, low zinc grade in the flue dust, high flue gas treatment cost, and no mention of the recovery of metallic iron.

[0010] Therefore, the present application is proposed. SUMMARY

[0011] The main purpose of the present application is to provide a device and method for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag, to solve the problems of low grade of copper and zinc, high energy consumption and inability to comprehensively recover valuable metals in the treatment of copper smelting slag in the prior art.

[0012] In order to achieve the above object, according to one aspect of the present application, a device for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag is provided, which comprises: a first smelting unit, comprising: a first smelting furnace provided with a first slag inlet, a first charging port, a first slag outlet, a copper tapping port and a first flue gas outlet, the first smelting furnace being used for smelting the copper smelting slag under the action of a first reducing agent and a siliceous slagging agent to obtain copper matte / copper alloy, first flue gas and liquid iron-containing tail slag; a siliceous slagging agent supply unit connected with the first charging port and used for providing the siliceous slagging agent into the first smelting furnace; a first reducing agent supply unit connected with the first charging port and used for providing the first reducing agent into the first smelting furnace; a first flue gas treatment unit connected with the first flue gas outlet and used for treating the first flue gas discharged therefrom to obtain zinc-containing dust or zinc-arsenic-containing dust; a second smelting unit, comprising: a second smelting furnace provided with a second charging port, a second slag outlet, an iron tapping port and a second flue gas outlet, the second smelting furnace being used for smelting the liquid iron-containing tail slag under the action of a second reducing agent and a calcareous slagging agent to obtain pig iron or ferrosilicon alloy, second flue gas and harmless tail slag; a calcareous slagging agent supply unit connected with the second charging port and used for providing the calcareous slagging agent into the second smelting furnace; a second reducing agent supply unit connected with the second charging port and used for providing the second reducing agent into the second smelting furnace; a second flue gas treatment unit connected with the second flue gas outlet and used for treating the second flue gas discharged therefrom to obtain zinc-containing dust; a negative pressure unit connected with the first smelting furnace and the second smelting furnace and used for providing a negative pressure environment to the hearth during the smelting process of the copper smelting slag and the smelting process of the liquid iron-containing tail slag; wherein the first smelting furnace and the second smelting furnace are the same CR furnace, and the first charging port is the second charging port, the first slag outlet is the second slag outlet, the copper tapping port is the iron tapping port, the first flue gas outlet is the second flue gas outlet, and the first flue gas treatment unit is the second flue gas treatment unit; or the first smelting furnace is a first CR furnace, the second smelting furnace is a second CR furnace, an electric furnace or a side-blown smelting furnace, and the second smelting furnace is further provided with a first slag inlet connected with the first slag outlet.

[0013] Further, when the first smelting furnace and the second smelting furnace are the same CR furnace, the CR furnace is in a horizontal structure, and the side thereof is further provided with a gas-permeable brick and / or a lance for blowing stirring gas into the slag layer in the smelting process of the copper smelting slag and the smelting process of the liquid-state iron-containing tailing slag; and the gas-permeable brick and / or the lance are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer; when the first smelting furnace is a first CR furnace and the second smelting furnace is a second CR furnace or an electric furnace, the first smelting furnace and the second smelting furnace are independently in a horizontal structure, and the side of each of the two is independently provided with a gas-permeable brick and / or a lance for blowing stirring gas into the slag layer in the smelting process thereof; and the gas-permeable brick and / or the lance are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer; when the first smelting furnace is a first CR furnace and the second smelting furnace is a side-blown smelting furnace, the first smelting furnace and the second smelting furnace are independently in a horizontal structure, and the side of each of the two is independently provided with a gas-permeable brick and / or a lance for blowing stirring gas into the slag layer in the smelting process thereof; and the gas-permeable brick and / or the lance are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer; at the same time, the second smelting furnace is further provided with a fuel side-blown lance for blowing fuel and oxygen-enriched air into the furnace for heating in the smelting process of the iron-containing tailing slag.

[0014] Further, the first slag inlet is arranged at the top of the first smelting furnace and close to one end in the length direction thereof, the first slag outlet and the copper tapping hole are arranged at the other end side of the first smelting furnace away from the first slag inlet, and the gas-permeable brick and / or the lance are arranged on the side wall of the first smelting furnace close to the first slag inlet.

[0015] Further, when the first smelting furnace is a first CR furnace and the second smelting furnace is a second CR furnace, an electric furnace or a side-blown smelting furnace, in the second smelting furnace, the second slag inlet is arranged at the top of the second smelting furnace and close to one end in the length direction thereof, the second slag outlet and the iron tapping hole are arranged at the other end side of the second smelting furnace away from the second slag inlet, and the gas-permeable brick and / or the lance are arranged on the side wall of the second smelting furnace close to the second slag inlet.

[0016] Further, in the first smelting furnace, the shortest distance between the side wall where the copper tapping hole is located and the gas-permeable brick and / or the lance in the length direction of the furnace body is L1, and the total length of the furnace body of the first smelting furnace is L, and L1 / L = 1 / 5-1 / 3.

[0017] Further, when the first smelting furnace is a first CR furnace and the second smelting furnace is a second CR furnace, an electric furnace or a side-blown smelting furnace, in the second smelting furnace, the shortest distance between the side wall where the iron tapping hole is located and the gas-permeable brick and / or the lance in the length direction of the furnace body is L1', and the total length of the furnace body of the second smelting furnace is L', and L1' / L' = 1 / 5-1 / 3.

[0018] Further, the first smelting furnace is provided with a plurality of heating electrodes on the top thereof, which are arranged above the slag layer where the air brick and / or the lance are located; when the first smelting furnace is a first CR furnace, and the second smelting furnace is a second CR furnace or an electric furnace, the top of the second smelting furnace is also provided with a plurality of heating electrodes, which are arranged above the slag layer where the air brick and / or the lance are located.

[0019] Further, when the first smelting furnace and the second smelting furnace are the same CR furnace, the inner side wall of the furnace body is provided with refractory furnace bricks and copper water-cooled jackets, wherein the refractory furnace bricks are arranged on the side wall above the molten pool and the side wall corresponding to the slag layer below the molten pool, and a part of the copper water-cooled jacket is arranged between the upper and lower refractory furnace bricks and directly contacts the molten pool, and another part of the copper water-cooled jacket is arranged between the lower refractory furnace brick and the side wall; or the refractory furnace bricks are arranged on the entire side wall in the furnace body, and the copper water-cooled jacket is arranged on the side wall corresponding to the molten pool and located between the refractory furnace bricks and the side wall.

[0020] Further, when the first smelting furnace is a first CR furnace, and the second smelting furnace is a second CR furnace, an electric furnace or a side-blown smelting furnace, the inner side wall of the first smelting furnace and the second smelting furnace is independently provided with refractory furnace bricks and copper water-cooled jackets; wherein in the first smelting furnace, the refractory furnace bricks are arranged on the side wall above the molten pool and the side wall corresponding to the slag layer below the molten pool, and the copper water-cooled jacket is arranged between the upper and lower refractory furnace bricks and directly contacts the molten pool; or the refractory furnace bricks are arranged on the entire side wall in the furnace body, and the copper water-cooled jacket is arranged on the side wall corresponding to the molten pool and located between the refractory furnace bricks and the side wall; in the second smelting furnace, the refractory furnace bricks are arranged on the side wall above the molten pool and the side wall corresponding to the slag layer below the molten pool, and the copper water-cooled jacket is arranged between the upper and lower refractory furnace bricks and directly contacts the molten pool; or the refractory furnace bricks are arranged on the entire side wall in the furnace body, and the copper water-cooled jacket is arranged on the side wall corresponding to the molten pool and located between the refractory furnace bricks and the side wall.

[0021] Further, when the lance is arranged, the silicon slag-making agent supply unit, the first reducing agent supply unit, the calcium slag-making agent supply unit and the second reducing agent supply unit are respectively connected with the corresponding lance.

[0022] According to another aspect of the present application, there is also provided a method for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag, which is performed by using the device for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag described above, and the method comprises the following steps: step S1, transferring the copper smelting slag into the first smelting furnace, and supplying the siliceous slagging agent into the first smelting furnace through the siliceous slagging agent supply unit, and supplying the first reducing agent into the first smelting furnace through the first reducing agent supply unit; under the first negative pressure state, smelting the copper smelting slag under the action of the first reducing agent and the siliceous slagging agent to obtain copper matte / copper alloy, first flue gas and liquid iron-containing tailings; processing the first flue gas through the first flue gas processing unit to obtain zinc-containing dust and zinc-arsenic-containing dust; step S2, supplying the calcareous slagging agent into the second smelting furnace through the calcareous slagging agent supply unit, and supplying the second reducing agent into the second smelting furnace through the second reducing agent supply unit; under the second negative pressure state, smelting the liquid iron-containing tailings under the action of the second reducing agent and the calcareous slagging agent to obtain pig iron or silicon-iron alloy, second flue gas and harmless tailings; processing the second flue gas through the second flue gas processing unit to obtain zinc-containing dust; when the first smelting furnace and the second smelting furnace are the same CR furnace, after step S1 is completed, the copper matte / copper alloy is discharged through the copper tapping port, and then step S2 is performed; when the first smelting furnace is the first CR furnace, the second smelting furnace is the second CR furnace, the electric furnace or the side-blown smelting furnace, after step S1 is completed, the liquid iron-containing tailings are transferred into the second smelting furnace through the first slag tapping port and the first slag feeding port, and then step S2 is performed.

[0023] Further, in step S1, the slag type in the smelting process of the copper smelting slag is controlled to be FeO / SiO2=0.8-1.5, preferably FeO / SiO2=1-1.4; preferably, the siliceous slagging agent is selected from one or more of quartzite, quartz, river sand and sea sand; preferably, the first reducing agent is one or more of coal, coke, petroleum coke, graphite, carbon powder, wood, silicon-iron alloy and elemental silicon; preferably, the particle size of the siliceous slagging agent is 0.2-20 mm, and the particle size of the first reducing agent is 1-30 mm.

[0024] Further, in step S1, the operating temperature in the first smelting furnace is 1400-1600℃, preferably 1460-1550℃; the hearth operating pressure in the first smelting furnace is negative pressure-10--300 Pa.

[0025] Further, in step S1, the inert gas and / or reducing gas is introduced into the slag layer through the gas permeable bricks and / or the lances, and the gas flow rate of a single gas permeable brick or lance is 1-100 Nm3 / h; preferably, when introduced through the lances, the first reducing agent and the siliceous slagging agent are independently charged through the lances and / or the first charging port. 3

[0026] ​Further, in step S2, the slag type in the liquid-state iron-containing tailing smelting process is controlled to be a calcium-silicon slag type with CaO / SiO2=0.8-1.2 or a calcium-iron-silicon slag type with CaO / SiO2=0.3-0.6; preferably, the calcareous slag former is selected from one or more of calcium oxide, lime, limestone, magnesium oxide, and dolomite; preferably, the second reducing agent is one or more of coal, coke, petroleum coke, graphite, ferrosilicon alloy, elemental silicon, and hydrogen; preferably, the particle size of the calcareous slag former is 0.2-20 mm, and the particle size of the solid second reducing agent is 1-30 mm.

[0027] Further, in step S2, the operating temperature in the second smelting furnace is 1450-1650 DEG C, preferably 1480-1550 DEG C; and the hearth operating pressure in the second smelting furnace is negative pressure -5--200 Pa.

[0028] Further, in step S2, the inert gas and / or reducing gas is introduced into the slag layer through the gas permeable bricks and / or the lances; preferably, when introduced through the lances, the second reducing agent and the calcareous slag former are respectively independently charged through the lances and / or the second charging port.

[0029] Further, in step S2, when the second reducing agent and the calcareous slag former are added through the second charging port, the gas permeation amount of a single gas permeable brick or lance is 1-100 Nm 3 / h; and when the second reducing agent and the calcareous slag former are added through the lances, the gas permeation amount of a single lance is 50-500 Nm 3 / h.

[0030] The device provided by the application can recover copper, lead, zinc, antimony, gold, silver, iron and other non-ferrous and black elements in copper smelting slag, and deeply remove harmful elements such as arsenic in the slag, enrich arsenic, and realize comprehensive recovery of non-ferrous and black elements in copper slag. And the generated tailing is similar to iron smelting tailing, which is harmless tailing and can be directly built into materials. In short, the device provided by the application has the advantages of high efficiency, short process, low energy consumption, low cost, small land occupation, full recovery of valuable metal elements, and environmental friendliness. BRIEF DESCRIPTION OF DRAWINGS

[0031] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application, serve to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0032] Figure 1 A structure schematic diagram of a copper smelting slag valuable metal element comprehensive recovery and harmless treatment device according to an embodiment of the application is shown;

[0033] Figure 2A structure schematic diagram of a copper smelting slag valuable metal element comprehensive recovery and harmless treatment device according to a second embodiment of the present application is shown.

[0034] Figure 3 A structure schematic diagram of a copper smelting slag valuable metal element comprehensive recovery and harmless treatment device according to a third embodiment of the present application is shown.

[0035] Figure 4 A structure schematic diagram of a copper smelting slag valuable metal element comprehensive recovery and harmless treatment device according to a fourth embodiment of the present application is shown.

[0036] Figure 5 A curve of Gibbs free energy of valuable metal oxide reduction in copper smelting slag with temperature is shown.

[0037] In the above drawings, the following reference signs are used:

[0038] 10, first smelting furnace; 101, first slag inlet; 102, first charging port; 103, first slag outlet; 104, copper tapping port; 105, first flue gas outlet; 11, first flue gas treatment unit; 20, second smelting furnace; 201, second slag inlet; 202, second charging port; 203, second slag outlet; 204, iron tapping port; 205, second flue gas outlet; 21, second flue gas treatment unit; 12, refractory furnace brick; 13, copper water cooling jacket; 111, secondary combustion chamber; 112, waste heat boiler; 113, dust collection device; 114, quenching unit; 111', first secondary combustion chamber; 112', first waste heat boiler; 113', first dust collection device; 114', first quenching unit; 211, second secondary combustion chamber; 212, second waste heat boiler; 213, second dust collection device. DETAILED DESCRIPTION

[0039] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0040] As described in the background, the existing CR furnace process for treating copper smelting slag has the problem of low utilization rate of pyrite and other sulfidation agents in practice, and the addition of auxiliary materials such as pyrite and other sulfidation agents is to use pyrite to settle and drive the copper matte inclusions in the slag to settle, which fails to make the copper matte particles in the slag settle by themselves, and the copper matte grade is low (15% to 35%), which causes problems such as large treatment capacity, low grade, high energy consumption, etc. in the subsequent copper matte smelting process. Moreover, the process also has problems such as high sulfur content in flue gas, low zinc grade in smoke dust, high flue gas treatment cost, etc., and does not mention the recovery of metallic iron. In summary, the existing technology has problems such as low copper matte grade, high energy consumption, and inability to comprehensively recover valuable metals when treating copper smelting slag.

[0041] To solve the above problems, the inventors have proved through mechanism analysis and a large number of experimental researches that by adjusting the slag type, not adding sulfurizing agent and other auxiliary materials, and controlling the negative pressure, the interfacial tension between the slag and copper matte in the copper smelting slag smelting process and the reaction atmosphere can be controlled, so that the high-efficiency and high-proportion recovery of non-ferrous elements such as copper, zinc, lead, gold and silver can be realized, the copper matte with a copper grade of 60% to 80%, the copper alloy and the zinc oxide with a zinc content of more than 60% are obtained, and the tail slag with an iron content of 35% to 45% is produced. And by fully utilizing the waste heat of the tail slag, combined with further slag type regulation, the liquid-state iron-containing tail slag can be further smelted to obtain pig iron or ferrosilicon alloy, and the iron recovery rate reaches more than 95%. Based on this, the present application avoids the problems that the zinc-iron concentrate obtained by beneficiation is difficult to be high-value utilized and the iron recovery rate is low; at the same time, the pig iron produced can be directly used for steelmaking as a steelmaking raw material or auxiliary material.

[0042] Based on this, the present application provides a copper smelting slag valuable metal element comprehensive recovery and harmless treatment device. Figures 1 to 4As shown, the device comprises a first smelting unit, a second smelting unit and a negative pressure unit, the first smelting unit comprises a first smelting furnace 10, a siliceous slagging agent supply unit, a first reducing agent supply unit and a first flue gas treatment unit 11, the second smelting unit comprises a second smelting furnace 20, a calcareous slagging agent supply unit, a second reducing agent supply unit and a second flue gas treatment unit 21; the first smelting furnace 10 is provided with a first slag inlet 101, a first charging port 102, a first slag outlet 103, a copper tapping port 104 and a first flue gas outlet 105, and is used for smelting copper smelting slag under the action of the first reducing agent and the siliceous slagging agent to obtain copper matte / copper alloy, first flue gas and liquid iron-containing tailings; the siliceous slagging agent supply unit is connected with the first charging port 102 and is used for providing siliceous slagging agent into the first smelting furnace 10; the first reducing agent supply unit is connected with the first charging port 102 and is used for providing the first reducing agent into the first smelting furnace 10; the first flue gas treatment unit 11 is connected with the first flue gas outlet 105 and is used for treating the first flue gas discharged therefrom to obtain zinc-containing dust or zinc-arsenic-containing dust; the second smelting furnace 20 is provided with a second charging port 202, a second slag outlet 203, an iron tapping port 204 and a second flue gas outlet 205, and is used for smelting liquid iron-containing tailings under the action of the second reducing agent and the calcareous slagging agent to obtain pig iron or ferrosilicon alloy, second flue gas and harmless tailings; the calcareous slagging agent supply unit is connected with the second charging port 202 and is used for providing the calcareous slagging agent into the second smelting furnace 20; the second reducing agent supply unit is connected with the second charging port 202 and is used for providing the second reducing agent into the second smelting furnace 20; the second flue gas treatment unit 21 is connected with the second flue gas outlet 205 and is used for treating the second flue gas discharged therefrom to obtain zinc-containing dust; the negative pressure unit is connected with the first smelting furnace 10 and the second smelting furnace 20 and is used for providing a negative pressure environment to the hearth during the smelting process of the copper smelting slag and the smelting process of the liquid iron-containing tailings.

[0043] As shown in Figure 1 and 2 , the first smelting furnace 10 and the second smelting furnace 20 are the same CR furnace, and the first charging port 102 is the second charging port 202, the first slag outlet 103 is the second slag outlet 203, the copper tapping port 104 is the iron tapping port 204, the first flue gas outlet 105 is the second flue gas outlet 205, and the first flue gas treatment unit 11 is the second flue gas treatment unit 21; or, as shown in Figure 3 and 4 , the first smelting furnace 10 is a first CR furnace, the second smelting furnace 20 is a second CR furnace, an electric furnace or a side-blown smelting furnace, and the second smelting furnace 20 is further provided with a first slag inlet 201 connected with the first slag outlet 103.

[0044] The device provided by the present application can smelt liquid copper smelting slag under the action of a first reducing agent and a siliceous slag forming agent to obtain copper matte / copper alloy, first flue gas and liquid iron-containing tailing, and then recycle iron from the liquid iron-containing tailing to smelt the liquid iron-containing tailing under the action of a second reducing agent and a calcareous slag forming agent to obtain pig iron or ferrosilicon alloy, second flue gas and harmless tailing. The two-step process can be realized in one smelting furnace, i.e. CR furnace, or in two smelting furnaces connected by, for example, a chute.

[0045] Specifically, in the smelting process of the copper smelting slag, the siliceous slag forming agent is supplied to the first smelting furnace 10 by the siliceous slag forming agent supply unit, the first reducing agent is supplied to the first smelting furnace 10 by the first reducing agent supply unit, and the first smelting furnace 10 is in a negative pressure state by cooperating with the negative pressure unit, so that the slag viscosity, the interfacial tension with copper matte (and copper alloy, which are collectively discharged and will be stratified, the alloy is in the lower part and the copper matte is in the upper part, so they can be collected separately) and the reaction atmosphere can be effectively adjusted, the valuable elements such as copper, zinc, lead, antimony, gold and silver can be fully recovered, and the harmful elements such as arsenic can be deeply removed. This is mainly due to the fact that a large amount of iron in the copper smelting slag exists in the form of high-melting-point magnetic iron, causing part of the silicon oxide to exist in the form of an element, resulting in high slag viscosity, making it difficult for copper matte droplets to grow and settle, and the settling speed is slow; the present application reduces the slag viscosity by reducing the magnetic iron in the slag to FeO and the elemental silicon oxide existing in the slag and adding the silicon oxide slag forming agent, and accelerates the settling speed of the copper matte; at the same time, high-temperature smelting can also reduce the slag viscosity. The first slag forming agent is added mainly because the increase of the content of silicon oxide in the slag is beneficial to increase the interfacial tension of the molten slag, promote the separation of copper matte droplets in the slag, and make them grow and settle. Copper matte can exist as an independent phase in copper slag. However, due to the activity, any two substances have a reaction tendency, that is, copper matte and copper slag will react to a certain extent, resulting in the formation of a small amount of dissolved copper in the copper slag. FeO in the copper smelting slag is an alkaline substance, and silicon oxide is an acidic substance. The higher the basicity of the copper slag, the higher the free oxygen content in the slag, and the better the reactivity of the slag and copper matte, so the interfacial wettability of the slag and copper will be better (i.e. low interfacial tension, difficult to separate). Therefore, under high alkalinity, copper matte particles are difficult to agglomerate and grow and separate from the slag due to the good wettability (corresponding to low interfacial tension) between copper matte particles and copper slag. In the case of very low alkalinity, the free oxygen content in the slag is very low, and the reactivity of the slag and copper matte is very weak, resulting in poor wettability (high interfacial tension) between copper matte particles and slag. In the case of high interfacial tension, copper matte particles tend to agglomerate and grow, and separate from the copper slag to reduce the free energy of the system.

[0046] The copper smelting slag includes, but is not limited to, liquid copper smelting slag, converting slag and other intermediate slag in copper smelting. Optionally, copper smelting fume can also be treated. In the smelting process of the first smelting furnace 10, the slag viscosity, the interfacial tension with copper matte (and copper alloy) and the reaction atmosphere are adjusted, so that the valuable metal elements such as copper, gold and silver are separated from the slag and settled at the bottom of the molten pool, and the elements such as zinc, lead and arsenic are volatilized and discharged with the flue gas. The zinc-containing fume (lead-zinc fume) or zinc-arsenic-containing fume can be obtained by treating the flue gas in the first flue gas treatment unit. This step realizes the full separation and recovery of copper, zinc, lead, gold and silver from iron. At the same time, since the sulfidation agent is not added in the present application, the sulfur content in the slag can be greatly reduced, and the harmful elements such as arsenic in the slag can be deeply removed.

[0047] After the copper smelting slag is smelted in the first smelting furnace 10, when the first smelting furnace 10 and the second smelting furnace 20 are the same CR furnace, the copper matte / copper alloy is discharged, and then calcium slagging agent and second reducing agent are introduced into the first smelting furnace 10, so that the liquid iron-containing tail slag is further smelted under negative pressure to recover the iron resources therein and obtain pig iron (or ferrosilicon alloy), second flue gas and harmless tail slag. When the first smelting furnace 10 is the first CR furnace, the second smelting furnace 20 is the second CR furnace, the electric furnace or the side-blown smelting furnace, the liquid iron-containing tail slag can be sent into the second smelting furnace 20 through a chute for the above treatment. The zinc and lead elements that are not completely recovered in the first smelting process can be further reduced and volatilized in this section, and enter the second flue gas for treatment, so that zinc-containing fume can be obtained, and the zinc and lead content in the harmless tail slag can be reduced to less than 0.05%.

[0048] In summary, the device provided by the present application is used to treat copper smelting slag, realizes the segmented and comprehensive recovery of valuable metal elements in copper slag, and can obtain high-quality zinc oxide, high-grade copper matte / copper alloy and low-copper pig iron / ferrosilicon alloy. The process fully utilizes the waste heat of copper slag, has low investment cost, low energy consumption, high efficiency and environmental friendliness, and has broad technical prospects.

[0049] In a preferred embodiment, when the first smelting furnace 10 and the second smelting furnace 20 are the same CR furnace, the CR furnace is in a horizontal structure, and the side thereof is further provided with a gas-permeable brick and / or a lance for blowing stirring gas into the slag layer during the smelting process of the copper smelting slag and the smelting process of the liquid-state iron-containing tailings; and the gas-permeable brick and / or the lance are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer. When the first smelting furnace 10 is a first CR furnace, and the second smelting furnace 20 is a second CR furnace or an electric furnace, the first smelting furnace 10 and the second smelting furnace 20 are each independently in a horizontal structure, and the side of each of the two is independently provided with a gas-permeable brick and / or a lance for blowing stirring gas into the slag layer during the respective smelting process; and the gas-permeable brick and / or the lance are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer. When the first smelting furnace 10 is a first CR furnace, and the second smelting furnace 20 is a side-blown smelting furnace, the first smelting furnace 10 and the second smelting furnace 20 are each independently in a horizontal structure, and the side of each of the two is independently provided with a gas-permeable brick and / or a lance for blowing stirring gas into the slag layer during the respective smelting process; and the gas-permeable brick and / or the lance are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer. At the same time, the second smelting furnace 20 is further provided with a fuel side-blown lance for blowing fuel (such as natural gas, pulverized coal, etc.) and oxygen-enriched air (oxygen concentration greater than that in air, such as oxygen-enriched air with an oxygen concentration of 30-98%) into the furnace for heating during the smelting process of the iron-containing tailings. By making the above-mentioned arrangements, stirring gas can be blown into the slag layer during the smelting process, so as to facilitate the settlement recovery of copper matte / copper alloy (or pig iron, ferrosilicon alloy). In actual operation, the amount of stirring gas can be controlled in a small amount state to avoid high dust rate caused by large amount of blowing, which seriously affects the zinc oxide grade, and is more conducive to the settlement recovery of copper, gold and silver, etc. In addition, when a side-blown smelting furnace is used as the second smelting furnace, the lance can provide reducing agent, heat and stirring kinetic energy, thereby performing deep reduction.

[0050] In a preferred embodiment, the first slag inlet 101 is arranged at the top of the first smelting furnace 10 and close to one end of the length direction of the first smelting furnace 10, and the first slag outlet 103 and the copper tapping hole 104 are arranged at the other end of the side of the first smelting furnace 10 away from the first slag inlet 101, and the tuyere and / or the lance are arranged on the side wall of the first smelting furnace 10 close to the first slag inlet 101. Such arrangement can promote the smelting process to be more sufficient. Similarly, in a preferred embodiment, when the first smelting furnace 10 is a first CR furnace, and the second smelting furnace 20 is a second CR furnace, an electric furnace or a side-blown smelting furnace, in the second smelting furnace 20, the second slag inlet 201 is arranged at the top of the second smelting furnace 20 and close to one end of the length direction of the second smelting furnace 20, and the second slag outlet 203 and the iron tapping hole 204 are arranged at the other end of the side of the second smelting furnace 20 away from the second slag inlet 201, and the tuyere and / or the lance are arranged on the side wall of the second smelting furnace 20 close to the second slag inlet 201.

[0051] In order to make the smelted slag layer and the lower layer fully separated, and further improve the copper matte / copper alloy settling separation effect, in a preferred embodiment, in the first smelting furnace 10, the shortest distance between the side wall where the copper tapping hole 104 is located and the tuyere and / or the lance along the length direction of the furnace body is L1, and the total length of the furnace body of the first smelting furnace 10 is L, and then L1 / L = 1 / 5-1 / 3. Similarly, when the first smelting furnace 10 is a first CR furnace, and the second smelting furnace 20 is a second CR furnace, an electric furnace or a side-blown smelting furnace, in the second smelting furnace 20, the shortest distance between the side wall where the iron tapping hole 204 is located and the tuyere and / or the lance along the length direction of the furnace body is L1', and the total length of the furnace body of the second smelting furnace 20 is L', and then L1' / L' = 1 / 5-1 / 3. In actual implementation, it is preferred that 1-50 tuyeres or small lances are arranged on the side wall of the first smelting furnace 10 and the second smelting furnace 20, and arranged in a single row along the length direction of the furnace body. If a lance is used, the diameter of the lance is 1-30 mm. The arrangement of the tuyeres and the lances is mainly to promote the formation of a slightly stirred molten pool, to improve the aggregation and growth speed of copper matte droplets, to improve the reaction speed of molten slag with slagging agent and reducing agent, to improve the volatilization speed of reduced zinc and lead, and to reduce the proportion of lead sinking into copper matte. The above arrangement is more conducive to the smelting of copper smelting slag, and facilitates more sufficient separation of copper, gold and silver from slag.

[0052] In a preferred embodiment, the top of the first smelting furnace 10 is provided with a plurality of heating electrodes arranged above the slag layer where the tuyere and / or the lance are arranged; when the first smelting furnace 10 is a first CR furnace, and the second smelting furnace 20 is a second CR furnace or an electric furnace, the top of the second smelting furnace 20 is also provided with a plurality of heating electrodes arranged above the slag layer where the tuyere and / or the lance are arranged. In this way, the electrode heating zone is arranged corresponding to the injection zone of the stirring gas, and it is also more conducive to the smelting process to be fully carried out.

[0053] More preferably, when the first smelting furnace 10 and the second smelting furnace 20 are the same CR furnace, the inner side wall of the furnace body is provided with refractory furnace bricks 12 and copper water cooling jackets 13, wherein, as shown in Figure 1 , the refractory furnace bricks 12 are arranged on the side walls corresponding to the molten pool above and the slag layer below the molten pool, and a part of the copper water cooling jacket 13 is arranged between the upper and lower refractory furnace bricks and directly contacts the molten pool, and another part of the copper water cooling jacket 13 is arranged between the lower refractory furnace brick 12 and the side wall; or, as shown in Figure 2 , the refractory furnace bricks 12 are arranged on the entire side wall in the furnace body, and the copper water cooling jacket 13 is arranged on the side wall corresponding to the molten pool and located between the refractory furnace brick 12 and the side wall. When the first smelting furnace 10 is a first CR furnace, and the second smelting furnace 20 is a second CR furnace, an electric furnace or a side-blown smelting furnace, the inner side wall of the first smelting furnace 10 and the second smelting furnace 20 is respectively independently provided with refractory furnace bricks 12 and copper water cooling jackets 13; wherein, as shown in Figure 3 , in the first smelting furnace 10, the refractory furnace bricks 12 are arranged on the side walls corresponding to the molten pool above and the slag layer below the molten pool, and the copper water cooling jacket 13 is arranged between the upper and lower refractory furnace bricks 12 and directly contacts the molten pool; or, as shown in Figure 4 , the refractory furnace bricks 12 are arranged on the entire side wall in the furnace body, and the copper water cooling jacket 13 is arranged on the side wall corresponding to the molten pool and located between the refractory furnace brick 12 and the side wall; as shown in Figure 3 , in the second smelting furnace 20, the refractory furnace bricks 12 are arranged on the side walls corresponding to the molten pool above and the slag layer below the molten pool, and the copper water cooling jacket 13 is arranged between the upper and lower refractory furnace bricks 12 and directly contacts the molten pool; or, as shown in Figure 4 , the refractory furnace bricks 12 are arranged on the entire side wall in the furnace body, and the copper water cooling jacket 13 is arranged on the side wall corresponding to the molten pool and located between the refractory furnace brick 12 and the side wall.

[0054] Preferably, when the lance is provided, the silicon slag-making agent supply unit, the first reducing agent supply unit, the calcium slag-making agent supply unit, and the second reducing agent supply unit are respectively independently connected with the corresponding lance. In this way, the above first reducing agent, second reducing agent, silicon slag-making agent, and calcium slag-making agent can be independently added in the form of a charging port and / or in the form of a lance injection, and the operation is flexible and variable.

[0055] Preferably, when the first smelting furnace 10 and the second smelting furnace 20 are the same CR furnace, the first flue gas and the second flue gas can share the same flue gas treatment unit, as shown in Figure 1 and 2As shown, the first flue gas treatment unit 11 includes a secondary combustion chamber 111, a waste heat boiler 112, a dust collection device 113 and a quenching unit 114 connected in sequence; when the first smelting furnace 10 is a first CR furnace, the second smelting furnace 20 is a second CR furnace, an electric furnace or a side-blown smelting furnace, the two furnaces can share the same flue gas treatment unit, which is not shown in the figure and can specifically include a secondary combustion chamber 111, a waste heat boiler 112, a dust collection device 113 and a quenching unit 114 connected in sequence; or, as shown in Figure 3 and 4 As shown, the first flue gas treatment unit 11 includes a first secondary combustion chamber 111', a first waste heat boiler 112', a first dust collection device 113' and a first quenching unit 114' connected in sequence, and the second flue gas treatment unit 21 includes a second secondary combustion chamber 211, a second waste heat boiler 212 and a second dust collection device 213 connected in sequence. In this way, the first flue gas can be sequentially subjected to secondary combustion, waste heat recovery, dust collection to obtain zinc-containing dust, and quenching to obtain zinc-arsenic-containing dust, and the second flue gas can be sequentially subjected to secondary combustion, waste heat recovery and dust collection to obtain zinc-containing dust. Any of the above four setting modes can be used, and the first setting mode saves cost when the furnace is built. In these setting modes, the metal can be prevented from contacting the copper water jacket, and the furnace lining slagging can be realized at the same time.

[0056] To make the feeding more uniform, preferably, the first feeding port 102 is 1 to 20, which is distributed on the top of the furnace body, such as part of which is close to the first slag inlet and part of which is between the electrodes. When two furnace bodies are used for treatment, the second smelting furnace can be a CR furnace or an electric furnace. The electric furnace can be circular, racetrack-shaped, rectangular, oval or the like. The two furnace bodies are preferably arranged in steps, i.e., the horizontal height of the second smelting furnace is lower than that of the first smelting furnace, and the two are connected by a chute for easy transfer of the liquid iron-containing tailings.

[0057] According to another aspect of the present application, there is also provided a method for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag, which is performed by using the device for comprehensive recovery and harmless treatment of valuable metal elements in copper smelting slag, and the method comprises the following steps: step S1, transferring the copper smelting slag into the first smelting furnace 10, and supplying the siliceous slagging agent into the first smelting furnace 10 through the siliceous slagging agent supply unit, and supplying the first reducing agent into the first smelting furnace 10 through the first reducing agent supply unit; under the first negative pressure state, smelting the copper smelting slag under the action of the first reducing agent and the siliceous slagging agent to obtain copper matte / copper alloy, first flue gas and liquid iron-containing tailing; treating the first flue gas through the first flue gas treatment unit 11 to obtain zinc-containing dust and zinc-arsenic-containing dust; step S2, supplying the calcium slagging agent into the second smelting furnace 20 through the calcium slagging agent supply unit, and supplying the second reducing agent into the second smelting furnace 20 through the second reducing agent supply unit; under the second negative pressure state, smelting the liquid iron-containing tailing under the action of the second reducing agent and the calcium slagging agent to obtain pig iron or ferrosilicon alloy, second flue gas and harmless tailing; treating the second flue gas through the second flue gas treatment unit 21 to obtain zinc-containing dust; when the first smelting furnace 10 and the second smelting furnace 20 are the same CR furnace, after step S1 is completed, the copper matte / copper alloy is discharged through the copper discharge port 104, and then step S2 is performed; when the first smelting furnace 10 is a first CR furnace, the second smelting furnace 20 is a second CR furnace, an electric furnace or a side-blown smelting furnace, after step S1 is completed, the liquid iron-containing tailing is transferred into the second smelting furnace 20 through the first slag discharge port 103 and the first slag inlet port 201, and then step S2 is performed.

[0058] The method provided by the present application can realize the segmented and comprehensive recovery of valuable metal elements in copper slag, and can obtain high-quality zinc oxide, high-grade copper matte / copper alloy and low-copper pig iron / ferrosilicon alloy. The process fully utilizes the waste heat of copper slag, has low investment cost, low energy consumption, high efficiency and environmental friendliness, and has wide technical prospect.

[0059] In actual operation, the copper smelting slag can be transferred from the copper smelting furnace into the first smelting furnace 10 through a chute or a ladle, and the first reducing agent and the siliceous slagging agent are added into the furnace according to the batching scheme through a belt or other means under the heating state of the heating electrode and the negative pressure condition to perform the first-stage smelting. The slagging, copper matte / copper alloy separation, selective reduction and volatilization of zinc, lead and arsenic, and the reduction of part of the iron are completed in the furnace. The obtained liquid iron-containing tailing contains less than 0.4% of copper, less than 0.8% of zinc, less than 0.2% of lead and less than 0.03% of arsenic. The obtained copper matte / copper alloy has a high copper grade, which can reach 60% to 80%. The obtained zinc-containing dust also has a high zinc content, and the zinc content is 65% to 80% and the lead content is 5% to 20%. The recovery rate of gold and silver in the treated copper smelting slag can be greater than 95%. The copper matte / copper alloy can be directly smelted in a copper blowing furnace or an anode furnace, and the high-quality zinc oxide can be used for zinc and lead smelting.

[0060] A siliceous slag-forming agent is used in the smelting of the first smelting furnace 10. Silicon oxides exist as molecular polyhedra in the liquid slag, while iron, calcium, and magnesium oxides exist as ions. Copper matte exists in a similar form to iron, calcium, and magnesium oxides. Adding silicon oxides can increase the interfacial tension between copper matte and slag, promoting the aggregation and growth of copper matte droplets. To more fully utilize these effects and further improve the sedimentation and separation of copper matte / copper alloy, in a preferred embodiment, in step S1, the slag composition during the copper smelting process is controlled to be FeO / SiO2 = 0.8–1.5, preferably FeO / SiO2 = 1–1.4. Preferably, the siliceous slag-forming agent uses a substance rich in SiO2, such as one or more selected from quartz, river sand, and sea sand.

[0061] The primary purpose of the first reducing agent is twofold: ① A large amount of iron in the copper slag exists as magnetic ferrophosphate, resulting in high slag viscosity. Adding the reducing agent reduces the magnetic ferrophosphate to FeO, which then reacts with silica to form ferrous silicate, reducing slag viscosity and promoting copper matte settling; ② It reduces oxides of elements such as zinc, lead, and arsenic. Preferably, the first reducing agent is one or more of coal, coke, petroleum coke, graphite, carbon powder, wood, ferrosilicon alloy, and elemental silicon. To facilitate feeding and ensure a more complete reaction, preferably, the particle size of the siliceous slag-forming agent is 0.2–20 mm, and the particle size of the first reducing agent is 1–30 mm.

[0062] In a preferred embodiment, in step S1, the operating temperature in the first smelting furnace 10 is 1400–1600°C, preferably 1460–1550°C; the furnace operating pressure in the first smelting furnace 10 is a negative pressure of -10 to -300 Pa. This operating temperature is chosen because when the temperature reaches above 1200°C, zinc oxide is preferentially reduced compared to iron oxide, and above 200°C, its preferential reduction is even stronger. At these temperatures, the first smelting furnace 10 of this invention can more fully perform selective reduction, preferentially reducing magnetic iron, zinc oxide, lead oxide, and arsenic oxide in the slag to FeO and elemental zinc, lead, and arsenic, achieving deep removal of zinc, lead, and arsenic, and reducing viscosity to achieve sufficient sedimentation and separation of copper matte / copper alloy. In particular, the iron content in copper slag is high; if the temperature is low, a large amount of iron is reduced, resulting in a low grade of copper matte (the Gibbs free energy of the reduction of valuable metal oxides in copper smelting slag as a function of temperature is shown in the curve). Figure 5 As shown in the diagram, controlling the temperature within the aforementioned range in this invention is more conducive to improving the grade of copper matte. The aforementioned negative pressure conditions also facilitate slag-matte separation, and the small volume of flue gas allows for sufficient volatilization of zinc and lead, resulting in a higher zinc grade in the formed zinc-containing flue dust. Excessive negative pressure leads to excessively high zinc-lead partial pressures within the furnace, hindering the volatilization of zinc and lead reduced in the molten pool; excessively high negative pressure results in significant air leakage within the furnace, causing a large amount of reducing agent to be burned, leading to excessively low reducing agent utilization.

[0063] Preferably, the first reducing agent is added in an amount of 2.5-8% of the copper smelting slag, which is more conducive to promoting the valuable metals such as copper, gold and silver to be separated and settled in the form of copper matte / copper alloy, a small amount of iron to be reduced and settled, and elements such as zinc, lead and arsenic to be present in the form of oxides in the slag and to be reduced into elements and volatilized into flue gas after the addition of the reducing agent. Preferably, the power density of the heating electrode in the first smelting furnace is 50-500 kW / m 2 , preferably 150-400 kW / m 2 .

[0064] In a preferred embodiment, in step S1, the inert gas and / or reducing gas is introduced into the slag layer through the gas permeable bricks and / or the lances, and the gas flow rate of a single gas permeable brick or lance is 1-100 Nm 3 / h. In the above first stage, i.e. in the first smelting furnace 10, the inert gas and / or reducing gas is introduced into the slag layer (as the stirring gas), but the gas flow rate should not be too large, which will cause strong stirring, resulting in too large amount of dust, causing the zinc grade of the zinc-rich dust to be greatly reduced, and at the same time, causing too large amount of flue gas, taking away too much heat, and increasing energy consumption. The present application selects slight stirring to accelerate the reaction speed of the oxides of zinc, lead, iron and arsenic with the reducing agent, to promote the aggregation and growth of the copper matte micro-droplets and the reduced iron micro-droplets, to accelerate the volatilization of the reduced zinc and lead, and to reduce the amount of lead entering the copper matte. The above inert gas includes but is not limited to nitrogen and argon, and the reducing gas includes but is not limited to natural gas, coal gas, coal gas, blast furnace gas and hydrogen.

[0065] Preferably, when introduced through the lances, the first reducing agent and the silicon-based slagging agent are each independently added through the lances and / or the first charging port 102. The above addition mode is flexible and adjustable, which is conducive to dispersing the addition of the materials, improving the uniformity of the system and improving the smelting efficiency, which should be understood by those skilled in the art and will not be described here.

[0066] In the actual smelting process, the copper smelting slag can be continuously introduced into the first smelting furnace through the chute, or can be intermittently introduced; the silicon-based slagging agent and the first reducing agent can be continuously introduced into the first smelting furnace, or can be intermittently introduced; a sealing structure is provided in the first smelting furnace to avoid serious electrode burnout.

[0067] In the second stage, i.e. the smelting process of the liquid iron-containing tailings, the calcium-based slagging agent and the second reducing agent are used to conduct slagging reduction, the metallic iron is reduced and settled, the residual copper is reduced and settled with the metallic iron, and the zinc and lead oxides not reduced in the first stage are further reduced and volatilized into the flue dust. In order to further improve the slagging reduction effect, more preferably, in step S2, the slag type in the smelting process of the liquid iron-containing tailings is controlled to be a calcium-silicon slag type: CaO / SiO2=0.8-1.2, or a calcium-iron-silicon slag type: CaO / SiO2=0.3-0.6. When the slag type is the former, the iron content in the tailings can be controlled to be less than 1%, and when the slag type is the latter, the iron content in the tailings is 5-8%. After the second stage smelting, low-copper pig iron (copper content <0.7%, iron content >96%), zinc-rich flue dust (zinc content >40%), and harmless pyrometallurgical tailings can be obtained.

[0068] The main function of the calcium-based slagging agent is to slag the silicon oxide in the liquid iron-containing tailings, improve the reduction tendency of iron oxides, and promote the separation of slag and iron. In order to more fully play this role, preferably, the calcium-based slagging agent is selected from one or more of calcium oxide, lime, limestone, magnesium oxide, and dolomite; preferably, the second reducing agent is one or more of coal, coke, petroleum coke, graphite, ferrosilicon alloy, elemental silicon, and hydrogen; preferably, the particle size of the calcium-based slagging agent is 0.2-20 mm, and the particle size of the solid second reducing agent is 1-30 mm. Preferably, the addition amount of the second reducing agent is 10-30% by weight of the liquid iron-containing tailings, which realizes deep recovery of iron, zinc, and lead, and produces harmless tailings (zinc content <0.05% and lead content <0.05 in the tailings). In actual production, the pig iron obtained can be used for cast iron and cast steel production or as scrap steel for steelmaking, and the zinc-containing flue dust can be used for zinc and lead smelting and recovery.

[0069] In a preferred embodiment, in step S2, the operating temperature in the second smelting furnace 20 is 1450-1650°C, preferably 1480-1550°C, and the operating pressure in the hearth of the second smelting furnace 20 is a negative pressure of -5 to -200 Pa. Under such conditions, the separation of iron and slag can be more fully conducted, and the residual zinc oxide is reduced and volatilized to form zinc-containing flue dust. In particular, under the above negative pressure condition, the utilization rate of the second reducing agent is improved, the amount of flue gas is reduced, and the energy consumption is reduced.

[0070] Preferably, in step S2, inert gas and / or reducing gas are introduced into the slag layer through the gas permeable bricks and / or the lances; preferably, when introduced through the lances, the second reducing agent and the calcium-based slagging agent are independently added through the lances and / or the second charging port 202. More preferably, in step S2, when the second reducing agent and the calcium-based slagging agent are added through the second charging port 202, the gas flow rate of a single gas permeable brick or lance is 1-100 Nm 3 / h; when the second reducing agent and the calcium-based slagging agent are added by the spray gun, the ventilation amount of a single spray gun is 50-500 Nm 3 / h.

[0071] In this way, the feeding mode of the second reducing agent and the calcium-based slagging agent is flexible and controllable, and the operation is convenient. Especially when two smelting furnaces are used, in the second smelting furnace, the feeding mode of the calcium-based slagging agent and the second reducing agent mainly has two modes: ① the calcium-based slagging agent and the second reducing agent are added at the charging port 202 on the top of the furnace, and 1-50 air-pervious bricks / small side-blown spray guns are arranged in the height direction of the slag layer, and a single row is arranged in the length direction of the furnace body to slightly stir the molten slag, and the gas amount is 1-100 Nm 3 / h, and the diameter of the spray gun is 1-30 mm; ② 1-50 spray guns are arranged in the height direction of the slag layer, and a single row is arranged in the length direction of the furnace body to slightly stir the molten slag, and the gas amount is 50-500 Nm3 / h; the gas can be inert gas such as nitrogen and argon, or reducing gas such as natural gas, coal gas, blast furnace gas and hydrogen; meanwhile, the calcium-based slagging agent and the second reducing agent are sprayed into the furnace by the side-blown spray gun (concentrated phase conveying is preferred, and the solid-gas ratio is 1-40 kg / m 3 ).

[0072] The first flue gas obtained in the above treatment process is preferably sequentially subjected to secondary combustion treatment, waste heat recovery treatment and dust collection to obtain zinc-containing dust (the temperature is reduced to > 250 DEG C, and zinc and lead oxides are precipitated first), and is rapidly cooled to obtain zinc-arsenic-containing dust (in the rapid cooling process, the temperature is too low to generate glassy arsenic); the second flue gas is preferably sequentially subjected to secondary combustion treatment, waste heat recovery treatment and dust collection to obtain zinc-containing dust.

[0073] In summary, the above-mentioned device and method of the present application for treating copper smelting slag have the following beneficial effects:

[0074] 1. One CR furnace can be used to process in stages, or two smelting furnaces can be used to process in steps; the equipment is flexible, the investment is small, the metal elements in the two-step recovered slag are deeply removed from harmful elements such as arsenic, and harmless pyrometallurgical tailings are produced, the raw materials for treatment are all liquid slag, and the cost is low.

[0075] 2. Air-pervious bricks / small side-blown spray guns can be arranged to spray inert gas or reducing gas to slightly stir the molten pool, improve the reaction efficiency, improve the aggregation and sedimentation speed of copper matte droplets, and accelerate the volatilization of zinc and lead;

[0076] 3. The single smelting device and the two smelting devices are preferably electric heating treatment, the energy utilization rate is high, the flue gas treatment cost is low; the two smelting devices can be flexibly arranged with air-pervious bricks, small spray guns and ordinary spray guns according to the production process characteristics.

[0077] 4. The smelting furnace can use a cooling water jacket to hang slag in the slag layer.

[0078] 5. Using electric heating as an energy source can significantly reduce the amount of smoke and dust and improve the quality of smoke and dust.

[0079] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0080] Example 1

[0081] The technology and apparatus described in this case are used to treat liquid copper smelting slag, such as... Figure 1 As shown, the process conditions are as follows:

[0082] The annual processing capacity of liquid copper smelting slag is 300,000 tons. The liquid copper smelting slag flows into the CR furnace via a chute. Coal and quartz are added at the auxiliary feed port, with coal accounting for 5% and quartz accounting for 4% of the slag. The smelting temperature is 1450℃, the smelting time is 2 hours, the negative pressure is -50Pa, and no permeable bricks / spray guns are installed. The slag type is ferrosilicon slag with Fe / SiO2 = 1.4. The product is 71% high-grade copper matte and 68% zinc oxide dust. Arsenic-rich dust and liquid iron-containing tailings (copper, zinc, and lead reduced to 0.39%, 0.8%, and 0.3%, respectively) were produced. After releasing the copper matte, 25% lime (percentage of liquid iron-containing tailings) and 18% coal (percentage of liquid iron-containing tailings) were added simultaneously. The slag type was CaO / SiO2 = 1. The smelting temperature was 1450℃, and the reduction and sedimentation were carried out for 2 hours. The product yielded 40% zinc-rich dust, 0.8% iron content in the tailings, and 96% iron content in the molten iron.

[0083] Example 2

[0084] The technology and apparatus described in this case are used to treat liquid copper smelting slag, such as... Figure 1 As shown, the process conditions are as follows:

[0085] The annual processing capacity of liquid copper smelting slag is 300,000 tons. The slag is fed into a CR furnace via a chute. Coal and quartz are added at the auxiliary feed inlet, with coal accounting for 5% and quartz for 4% of the slag. The smelting temperature is 1450℃, the smelting time is 1.5 hours, the negative pressure is -50 Pa, and the slag type is ferrosilicon slag (Fe / SiO2 = 1). Ten permeable bricks are installed, with each brick receiving 80 Nm³ of air injection. 3 / h, producing 71% high-grade copper matte, zinc oxide dust with 66% zinc content, arsenic dust, and liquid iron-containing tailings (copper, zinc, and lead reduced to 0.32%, 0.5%, and 0.2%, respectively); after releasing the copper matte, 25% lime (percentage of liquid iron-containing tailings) and 18% coal (percentage of liquid iron-containing tailings) are added simultaneously, the smelting temperature is 1450℃, reduction and sedimentation are carried out for 2 hours, CaO / SiO2=1, and 35% zinc-rich dust, 0.6% iron content in the tailings, and 96% iron content in the molten iron are obtained.

[0086] Example 3

[0087] The technology and apparatus described in this case are used to treat liquid copper smelting slag, such as... Figure 1 As shown, the process conditions are as follows:

[0088] The annual processing capacity of liquid copper smelting slag is 500,000 tons. The liquid copper smelting slag flows into the CR furnace through a chute. Coal and quartz are added at the auxiliary feed port, with coal accounting for 5% and quartz accounting for 4% of the slag. The smelting temperature is 1500℃, the smelting time is 2 hours, the negative pressure is -50Pa, and the slag type is iron-silicon slag with Fe / SiO2 = 1.2. No permeable bricks / spray guns are installed. The product is 71% high-grade copper matte, zinc oxide dust with 66% zinc content, arsenic dust, and liquid iron-containing tailings (copper, zinc, and lead are reduced to 0.35%, 0.55%, and 0.25%, respectively). After the copper matte is discharged, 25% lime and 18% coal are added at the same time. The smelting temperature is 1500℃, and the reduction and sedimentation is carried out for 2 hours with CaO / SiO2 = 1. The product is 38% zinc-rich dust, and the tailings contain 0.7% iron, with 96% iron content.

[0089] Example 4

[0090] The technology and apparatus described in this case are used to treat liquid copper smelting slag, such as... Figure 1 As shown, the process conditions are as follows:

[0091] The annual processing capacity of liquid copper smelting slag is 500,000 tons. The liquid copper smelting slag is continuously fed into the CR furnace through a chute. Coal and quartz are added at the auxiliary feed port, with coal accounting for 6% and quartz accounting for 3% of the slag. The smelting temperature is 1500℃, the smelting time is 2 hours, the negative pressure is -50Pa, and the slag type is iron-silicon slag with Fe / SiO2 = 0.8. No permeable bricks / spray guns are installed. The product is 70% high-grade copper matte, zinc oxide dust with 69% zinc content, arsenic dust, and liquid iron-containing tailings (copper, zinc, and lead are reduced to 0.4%, 0.6%, and 0.22%, respectively). After the copper matte is discharged, 12% lime and 10% coal are added at the same time. The smelting temperature is 1500℃, and the reduction and sedimentation is carried out for 2 hours with CaO / SiO2 = 0.5. The product is 42% zinc-rich dust, and the tailings contain 10% iron, with 95.5% iron content.

[0092] Example 5

[0093] The technology and apparatus described in this case are used to treat liquid copper smelting slag, such as... Figure 3 As shown, the process conditions are as follows:

[0094] The annual processing capacity of liquid copper smelting slag is 500,000 tons. The slag is continuously fed into the CR furnace via a chute. Coal and quartz are added at the auxiliary feed inlet, with coal accounting for 6% and quartz for 4% of the slag. The smelting temperature is 1500℃, the smelting time is 1.5 hours, the negative pressure is -50 Pa, and the slag type is ferrosilicon slag with an Fe / SiO2 ratio of 1.4. Fifteen permeable bricks are installed, with each brick receiving 60 Nm³ of air injection. 3 / h, producing 73% high-grade copper matte, 65% zinc oxide dust, arsenic dust, and liquid iron-containing tailings (copper, zinc, and lead reduced to 0.3%, 0.35%, and 0.15%, respectively); the liquid iron-containing tailings flow into the second smelting furnace via a chute, where 27% lime and 18% coal are added, the smelting temperature is 1500℃, reduction and sedimentation is carried out for 2 hours, CaO / SiO2 = 1, 15 permeable bricks are set up, and the air injection volume of each permeable brick is 60 Nm³. 3 / h, producing 35% zinc-rich flue dust, 0.5% iron content in tailings, and 96% iron content in molten iron.

[0095] Example 5

[0096] The technology and apparatus described in this case are used to treat liquid copper smelting slag, such as... Figure 3 As shown, the process conditions are as follows:

[0097] The annual processing capacity of liquid copper smelting slag is 500,000 tons. The liquid copper smelting slag is continuously fed into the CR furnace via a chute. Coal and quartz are added at the auxiliary feed port, with coal accounting for 4.5% and quartz accounting for 2% of the slag. The smelting temperature is 1550℃, the smelting time is 1.5 hours, the negative pressure is -50 Pa, and the slag type is ferrosilicon slag with an Fe / SiO2 ratio of 1.4. Fifteen permeable bricks are installed, with each permeable brick receiving 60 Nm³ of air injection. 3 / h, producing 73% high-grade copper matte, 65% zinc oxide dust, arsenic dust, and liquid iron-containing tailings (copper, zinc, and lead reduced to 0.38%, 0.6%, and 0.3%, respectively); the liquid iron-containing tailings flow into the second smelting furnace via a chute, where 27% lime and 18% coal are added, the smelting temperature is 1550℃, reduction and sedimentation is carried out for 2 hours, CaO / SiO2 = 0.8, 15 permeable bricks are installed, and the air injection volume of each permeable brick is 60 Nm³. 3 / h, producing 45% zinc-rich flue dust, 0.3% iron content in tailings, and 96% iron content in molten iron.

[0098] Example 6

[0099] The technology and apparatus described in this case are used to treat liquid copper smelting slag, such as... Figure 3 As shown, the process conditions are as follows:

[0100] The annual processing capacity of liquid copper smelting slag is 500,000 tons. The slag is continuously fed into the CR furnace via a chute. Coal and quartz are added at the auxiliary feed port, with coal accounting for 7% and quartz for 2% of the slag. The smelting temperature is 1550℃, the smelting time is 1.5 hours, the negative pressure is -150Pa, and the slag type is ferrosilicon slag with an Fe / SiO2 ratio of 1.4. Fifteen permeable bricks are installed, with each brick receiving 60 Nm³ of air injection. 3 / h, output 73% high-grade copper matte, zinc content 65% zinc oxide dust, arsenic dust, liquid iron-containing tailings (copper, zinc, lead reduced to 0.38%, 0.6%, 0.3% respectively); the liquid iron-containing tailings flow into the second smelting furnace through a chute, 27% lime and 18% coal are added, the smelting temperature is 1550°C, the reduction settlement is 2h, CaO / SiO2=0.8, 15 gas permeable bricks are set, and the gas amount of each gas permeable brick is 60Nm 3 / h, output 45% zinc-rich dust is obtained, and the iron content in the tailings is 0.3%, and the iron content is 96% molten iron.

[0101] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A device for comprehensive recovery and harmless treatment of valuable metal elements from copper smelting slag, characterized in that, Comprise: The first smelting unit comprises: The first smelting furnace (10) is provided with a first slag inlet (101), a first charging port (102), a first slag outlet (103), a copper tapping port (104) and a first flue gas outlet (105), and is used for smelting the copper smelting slag under the action of the first reducing agent and the siliceous slagging agent to obtain copper matte / copper alloy, first flue gas and liquid iron-containing tailings; The siliceous slagging agent supply unit is connected with the first charging port (102) and is used for providing the siliceous slagging agent into the first smelting furnace (10); The first reducing agent supply unit is connected with the first charging port (102) and is used for providing the first reducing agent into the first smelting furnace (10); The first flue gas treatment unit (11) is connected with the first flue gas outlet (105) and is used for treating the first flue gas discharged therefrom to obtain zinc-containing dust or zinc-containing arsenic dust; The second smelting unit comprises: The second smelting furnace (20) is provided with a second charging port (202), a second slag outlet (203), an iron tapping port (204) and a second flue gas outlet (205), and is used for smelting the liquid iron-containing tailings under the action of the second reducing agent and the calcareous slagging agent to obtain pig iron or silicon-iron alloy, second flue gas and harmless tailings; The calcareous slagging agent supply unit is connected with the second charging port (202) and is used for providing the calcareous slagging agent into the second smelting furnace (20); The second reducing agent supply unit is connected with the second charging port (202) and is used for providing the second reducing agent into the second smelting furnace (20); The second flue gas treatment unit (21) is connected with the second flue gas outlet (205) and is used for treating the second flue gas discharged therefrom to obtain zinc-containing dust; The negative pressure unit is connected with the first smelting furnace (10) and the second smelting furnace (20) and is used for providing a negative pressure environment to the hearth during the smelting process of the copper smelting slag and the smelting process of the liquid iron-containing tailings; The first smelting furnace (10) is a first CR furnace, and the second smelting furnace (20) is a second CR furnace, an electric furnace or a side-blown smelting furnace, and the second smelting furnace (20) is further provided with a second slag inlet (201) connected with the first slag outlet (103); the side walls of the first smelting furnace (10) and the second smelting furnace (20) are independently provided with refractory furnace bricks (12) and copper water-cooled jackets (13); in the first smelting furnace (10), the refractory furnace bricks (12) are arranged on the side walls above the molten pool and below the slag layer, and the copper water-cooled jackets (13) are arranged between the refractory furnace bricks (12) above and below and directly contact with the molten pool; or the refractory furnace bricks (12) are arranged on the entire side wall in the furnace body, and the copper water-cooled jackets (13) are arranged on the side wall corresponding to the molten pool and located between the refractory furnace bricks (12) and the side wall; in the second smelting furnace (20), the refractory furnace bricks (12) are arranged on the side walls above the molten pool and below the slag layer, and the copper water-cooled jackets (13) are arranged between the refractory furnace bricks (12) above and below and directly contact with the molten pool; or the refractory furnace bricks (12) are arranged on the entire side wall in the furnace body, and the copper water-cooled jackets (13) are arranged on the side wall corresponding to the molten pool and located between the refractory furnace bricks (12) and the side wall. When the first smelting furnace (10) is the first CR furnace, and the second smelting furnace (20) is the second CR furnace or the electric furnace, the first smelting furnace (10) and the second smelting furnace (20) are independently horizontal structures, and the side parts of the two are independently provided with air bricks and / or lances for blowing stirring gas into the slag layer during the smelting process; and the air bricks and / or lances are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer; when the first smelting furnace (10) is the first CR furnace, and the second smelting furnace (20) is the side-blown smelting furnace, the first smelting furnace (10) and the second smelting furnace (20) are independently horizontal structures, and the side parts of the two are independently provided with air bricks and / or lances for blowing stirring gas into the slag layer during the smelting process; and the air bricks and / or lances are arranged at a position 1 / 10-9 / 10 of the height of the slag layer from the bottom of the slag layer; at the same time, the second smelting furnace (20) is further provided with a fuel side-blown lance for blowing fuel and oxygen-enriched air into the furnace for heating during the smelting process of the iron-containing tailings.

2. The device according to claim 1, wherein the first slag inlet (101) is arranged at the top of the first smelting furnace (10) and close to one end in the length direction, the first slag outlet (103) and the copper tapping hole (104) are arranged at the other end side of the first smelting furnace (10) away from the first slag inlet (101), and the air bricks and / or lances are arranged on the side wall of the first smelting furnace (10) close to the first slag inlet (101). ​ 3. The device according to claim 1 or 2, characterized in that, in the second smelting furnace (20), the second slag inlet (201) is arranged at the top of the second smelting furnace (20) and is arranged close to one end of the length direction thereof, the second slag outlet (203) and the tapping hole (204) are arranged at the other end side of the second smelting furnace (20) away from the second slag inlet (201), and the air brick and / or the lance are arranged on the side wall of the second smelting furnace (20) close to the second slag inlet (201).

4. The apparatus of claim 3, wherein, in the first smelting furnace (10), the shortest distance between the side wall where the copper tapping hole (104) is arranged and the air brick and / or the lance along the length direction of the furnace body is L1, and the total length of the furnace body of the first smelting furnace (10) is L, and L1 / L = 1 / 5~1 / 3.

5. The apparatus of claim 4, wherein, in the second smelting furnace (20), the shortest distance between the side wall where the iron tapping hole (204) is arranged and the air brick and / or the lance along the length direction of the furnace body is L1', and the total length of the furnace body of the second smelting furnace (20) is L', and L1' / L' = 1 / 5~1 / 3.

6. The apparatus of claim 3, wherein, in the first smelting furnace (10), a plurality of heating electrodes are arranged at the top thereof and above the slag layer where the air brick and / or the lance is arranged; when the first smelting furnace (10) is the first CR furnace and the second smelting furnace (20) is the second CR furnace or the electric furnace, a plurality of heating electrodes are also arranged at the top of the second smelting furnace (20) and above the slag layer where the air brick and / or the lance is arranged.

7. The apparatus of claim 3, wherein, when the lance is arranged, the siliceous slag-making agent supply unit, the first reducing agent supply unit, the calcareous slag-making agent supply unit and the second reducing agent supply unit are respectively and independently connected with the corresponding lance.

8. A method for comprehensive recovery and harmless treatment of valuable metal elements from copper smelting slag, characterized in that, The method is performed by using the copper smelting slag valuable metal element comprehensive recovery and harmless treatment device according to any one of claims 1 to 7, and the method comprises the following steps: In step S1, the copper smelting slag is transported into the first smelting furnace (10), the siliceous slag-making agent is supplied into the first smelting furnace (10) through the siliceous slag-making agent supply unit, and the first reducing agent is supplied into the first smelting furnace (10) through the first reducing agent supply unit; under the first negative pressure state, the copper smelting slag is smelted under the action of the first reducing agent and the siliceous slag-making agent to obtain copper matte / copper alloy, first flue gas and liquid iron-containing tail slag; the first flue gas is treated by the first flue gas treatment unit (11) to obtain zinc-containing dust and zinc-arsenic-containing dust. In step S2, the calcareous slag-making agent is supplied into the second smelting furnace (20) through the calcareous slag-making agent supply unit, and the second reducing agent is supplied into the second smelting furnace (20) through the second reducing agent supply unit; under the second negative pressure state, the liquid iron-containing tail slag is smelted under the action of the second reducing agent and the calcareous slag-making agent to obtain pig iron or ferrosilicon alloy, second flue gas and harmless tail slag; the second flue gas is treated by the second flue gas treatment unit (21) to obtain zinc-containing dust. After the step S1, the liquid iron-containing tailings are transferred into the second smelting furnace (20) through the first slag tapping hole (103) and the second slag inlet (201), and then the step S2 is performed.

9. The method of claim 8, wherein, In the step S1, the slag type in the copper smelting slag smelting process is controlled to be FeO / SiO2=0.8~1.

5.

10. The method of claim 9, wherein, In the step S1, the slag type in the copper smelting slag smelting process is controlled to be FeO / SiO2=1~1.

4.

11. The method according to claim 8, wherein, the siliceous slag former is selected from one or more of quartzite, quartz, river sand, sea sand; the first reducing agent is one or more of coal, coke, petroleum coke, graphite, carbon powder, wood, ferrosilicon alloy, and elemental silicon; the particle size of the siliceous slag former is 0.2~20mm, and the particle size of the first reducing agent is 1~30mm.

12. The method according to any one of claims 8 to 11, characterized in that, In the step S1, the operating temperature in the first smelting furnace (10) is 1400~1600℃; and the hearth operating pressure in the first smelting furnace (10) is negative pressure -10~-300Pa.

13. The method of claim 12, wherein, In the step S1, the operating temperature in the first smelting furnace (10) is 1460~1550℃.

14. The method of claim 12, wherein, In the step S1, the inert gas and / or the reducing gas is introduced into the slag layer through the air brick and / or the lance, and the air flow rate of a single air brick or lance is 1-100 Nm 3 / h.

15. The method of claim 14, wherein, When introduced through a lance, the first reducing agent and the siliceous slag former are each independently introduced through a lance and / or a first charging port (102).

16. The method of claim 8, wherein, In the step S2, the slag type in the liquid iron-containing tailings smelting process is controlled to be a calcium-silicon slag type with CaO / SiO2=0.8~1.2 or a calcium-iron-silicon slag type with CaO / SiO2=0.3~0.

6.

17. The method according to claim 8, wherein, the calcareous slag former is selected from one or more of calcium oxide, lime, limestone, magnesium oxide, and dolomite; the second reducing agent is one or more of coal, coke, petroleum coke, graphite, ferrosilicon alloy, elemental silicon, and hydrogen; the particle size of the calcareous slag former is 0.2~20mm, and the particle size of the second reducing agent in solid state is 1~30mm.

18. The method of claim 8 or 16, wherein, In the step S2, the operating temperature in the second smelting furnace (20) is 1450~1650℃; and the hearth operating pressure in the second smelting furnace (20) is negative pressure -5~-200Pa.

19. The method of claim 18, wherein, In the step S2, the operating temperature in the second smelting furnace (20) is 1480~1550℃.

20. The method of claim 18, wherein, In the step S2, inert gas and / or reducing gas are introduced into the slag layer through a gas permeable brick and / or a lance.

21. The method of claim 20, wherein, When introduced through a lance, the second reducing agent and the calcareous slag former are each independently introduced through a lance and / or a second charging port (202).

22. The method of claim 21, wherein, The step S2, when the second reducing agent and the calcareous slagging agent are added through the second feeding port (202), the ventilation amount of single gas permeable brick or lance is 1-100 Nm 3 / h; when the second reducing agent and the calcareous slagging agent are added through the lance, the ventilation amount of single lance is 50-500 Nm 3 / h.

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