A method and apparatus for copper removal from molten iron by sulphation

Abstract

The present application relates to a kind of copper-containing molten sulfurization separation method and device, and specifically relates to copper-containing molten utilization field.The present application includes the following steps: step 1, copper slag is obtained by molten reduction, and the reduction slag is quenched after conditioning and is used as cement clinker;Step 2, copper-containing molten is transported to vortex sulfurization furnace;Step 3, sulfurizing agent is sucked into copper-containing molten under the action of vortex stirring and sulfurization reaction occurs;Step 4, after reaction, slag-gold separation is carried out, and copper-containing slag with main mineral phase chalcopyrite is obtained, which is used for copper recovery;Step 5, the remaining copper-removed molten after slag-gold separation is directly used for steelmaking.The present application efficiently separates and recovers copper in copper-containing molten by vortex sulfurization treatment, and the copper-removed molten is directly used for steelmaking, which avoids the influence of copper on steelmaking process, and is an efficient copper-containing molten sulfurization separation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper-containing molten iron treatment, and particularly relates to a method and device for sulfidizing separation of copper-containing molten iron. BACKGROUND

[0002] Copper slag is a solid waste discharged in the copper pyrometallurgical process, which can be mainly divided into smelting slag and converting slag. About 2-3 tons of copper slag is generated per ton of refined copper. At present, about 30 million tons of copper slag is discharged annually in China, and more than 300 million tons of copper slag has been accumulated. As a typical secondary resource, the copper grade in copper slag is more than 0.5wt.%-1.0wt.% (the copper grade in oxygen-enriched bottom blowing copper slag is as high as 4.0wt.% or more), which is much higher than the copper mining grade of 0.3wt.% in China. In addition, the iron grade in copper slag is as high as 40wt.% or more, which is much higher than the iron mining grade of 17wt.% in China. In addition, copper slag contains a large amount of precious metals such as gold, silver, nickel and cobalt. It is conservatively estimated that more than 150-200 thousand tons of copper is directly lost annually with the discharge of copper slag in China, and about 12 million tons of iron is lost, and about 2 million tons of standard coal is wasted in the form of heat. Such a large amount of solid waste has a difficult-to-recover impact on the ecological environment. The large amount of copper slag not only occupies land and pollutes the environment, but also causes great resource waste.

[0003] At present, the research on copper slag utilization technology mainly focuses on the utilization of copper alone or iron alone. In industry, flotation is mainly used to recover copper from oxygen-enriched smelting slag and converter slag. The recovery rate of copper by flotation can reach more than 90%, and the copper content in the recovered concentrate is more than 20wt.%. However, the copper content in the flotation tailings is still high (between 0.2wt.% and 0.3wt.%). Although this method recovers part of the copper, the copper slag needs to be slowly cooled before flotation, which requires a large number of slow cooling slag packages and occupies a large amount of slow cooling yard, resulting in high investment cost and complete waste of the sensible heat of hot copper slag. In addition, the fine iron-containing tailings after flotation (-400 mesh particles account for about 90%) are difficult to utilize again and can only be stored, which not only occupies land but also causes secondary pollution. More importantly, the flotation process only recovers part of the copper in the copper slag, and the iron and other valuable components are not recovered and utilized. A large amount of copper slag after flotation still has to be stored, and the problem of high-value and slag-free comprehensive utilization of copper slag has not been solved. Iron is mainly recovered from copper slag by carbon hot smelting reduction. The copper slag is mixed with a reducing agent and a slag forming agent to obtain copper-containing molten iron. Since copper can cause "copper brittleness" in the steelmaking process, the copper-containing molten iron is used to smelt copper-containing steel or copper-containing wear-resistant cast iron.

[0004] In recent years, relevant practitioners in China have carried out a large number of researches on the comprehensive utilization of copper slag. The patent with application number 201910859811.X proposes a "method for producing copper-containing steel and application of copper slag as coolant in the production of copper-containing steel", which adds crushed copper slag and scrap steel into the steelmaking converter, and adds lime for alkalinity control, and copper-containing steel can be obtained by smelting. The addition of copper slag not only introduces copper, but also plays a role as a coolant in the production of copper-containing steel. The patent with application number 201910432641.7 proposes a "production method of copper-containing steel", which uses molten copper slag as raw material, and finally obtains copper-containing steel through settlement treatment, smelting reduction treatment, steelmaking treatment and forming treatment. The patent with application number 201910432636.6 proposes a "production method of copper-containing cast iron", which uses molten copper slag as raw material, and finally obtains copper-containing cast iron through settlement treatment, smelting reduction treatment, smelting treatment and casting treatment. The above methods are all copper-containing molten iron obtained by smelting reduction of copper slag, which is refined to obtain copper-containing steel or copper-containing cast iron. Since the market consumption of copper-containing steel and copper-containing cast iron is small, it limits the large-scale application of copper-containing molten iron for the preparation of copper-containing steel and copper-containing cast iron in large quantities. The patent with application number 201710283371.9 proposes a "method for effective separation of copper element in high-copper iron material", which melts the high-copper iron material in batches, removes copper, and removes slag to obtain low-copper molten iron. The copper content in the molten iron after copper removal is 3.47wt.%~6.24wt.%, and the copper removal rate is 29%~62%. This method can only remove part of the copper in high-copper molten iron, and the copper removal rate is low, which cannot be applied to the copper removal treatment of low-copper molten iron. SUMMARY

[0005] The technical task of the present application is to solve the problems of the prior art, in order to realize the large-scale application of copper-containing molten iron, a method for sulfurization separation of copper-containing molten iron is provided. The present application efficiently separates and recovers copper from copper-containing molten iron by vortex sulfidation treatment, and the copper removal molten iron is directly used for steelmaking, which avoids the influence of copper on the steelmaking process. It is an efficient method and device for sulfurization separation of copper-containing molten iron.

[0006] The technical solution adopted by the present application to solve its technical problems is: a method for sulfurization separation of copper-containing molten iron, comprising the following steps:

[0007] Step 1, copper slag is reduced by smelting to obtain copper-containing molten iron, and the reduced slag is quenched by adjusting the water to be used as cement clinker;

[0008] Step 2, the copper-containing molten iron is transported to a vortex sulfidation furnace;

[0009] Step 3, the sulfurizing agent is sucked into the copper-containing molten iron under the action of vortex stirring to occur sulfidation reaction;

[0010] Step 4, after reaction, slag-gold separation is carried out to obtain copper-containing slag with chalcopyrite as the main mineral phase, which is used for copper recovery;

[0011] Step 5, the remaining copper-removed molten iron after slag-gold separation is directly used for steelmaking.

[0012] Further, in step 1, the copper slag used includes one or more of smelting slag, converting slag and flotation slag, and the copper content in the copper slag is 0.2wt.% to 3wt.%.

[0013] Further, in step 3, the addition amount of the sulfidation agent is 1wt.% to 10wt.% of the mass of the copper-containing molten iron, the sulfidation temperature is 1350°C to 1550°C, and the sulfidation time is 10min to 120min.

[0014] Further, in step 3, the sulfidation agent used is a mixture of pyrite, ferrous sulfide and elemental sulfur, and the ratio of the sulfidation agent is: pyrite 5wt.% to 50wt.%, ferrous sulfide 5wt.% to 50wt.% and elemental sulfur 5wt.% to 50wt.%, and the particle size after grinding is ≤100μm.

[0015] Further, in step 4, after slag-gold separation, the removal rate of copper in the copper-containing molten iron is ≥98%.

[0016] Further, in step 5, the copper content in the copper-removed molten iron is ≤0.10wt.%.

[0017] The application also provides a device for sulfidation separation of copper-containing molten iron, which is a vortex sulfidation furnace for vortex sulfidation treatment of copper-containing molten iron, and the vortex sulfidation furnace is a continuous or intermittent sulfidation furnace, a slag overflow port, a molten iron inlet chute, a molten iron outlet and a spraying port are arranged on the side wall of the furnace body of the vortex sulfidation furnace; the slag overflow port is arranged above the liquid level of the molten pool in the furnace body; the spraying port is arranged on the side wall and / or the bottom of the furnace body, and a spray gun is arranged on the spraying port; a vortex stirring paddle is further arranged in the furnace body, and the vortex stirring paddle comprises a stirring paddle shaft and paddles arranged thereon.

[0018] Further, the vortex stirring of the vortex sulfidation furnace is generated by the stirring paddle or the spraying gas; when the stirring paddle is used to generate the vortex, the stirring speed is 150rpm to 400rpm, and the sulfidation agent is directly added; when the spraying gas is used to generate the vortex, the sulfidation agent is added into the molten iron in the form of spraying (side blowing or bottom blowing), and in the spraying process, the inert gas is used to carry the sulfidation agent, and the spraying solid content is 5 to 80kg / Nm 3 .

[0019] Further, the vortex stirring paddle is made of refractory material, and the paddle blade and the stirring paddle shaft are doped with 1wt.%-10wt.% high-temperature-resistant stainless steel framework; the vortex stirring paddle performs vortex stirring, and the vortex has a downward entrainment effect, which is used to accelerate the entrainment speed of the composite vulcanizing agent and the vulcanization speed.

[0020] Further, the stirring paddle shaft is connected with the motor shaft through a flange sleeve, the flange sleeve comprises a bolted upper flange plate and a lower flange plate, the upper flange plate is connected with the motor shaft, and the lower flange plate is connected with a stainless steel sleeve; the stainless steel sleeve is internally threaded and is threadedly connected with the stirring paddle shaft provided with external threads.

[0021] Further, the contact surfaces of the upper and lower flange plates are respectively processed into matched concave-convex surfaces.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] 1. The present application provides a method and device for copper-containing molten iron sulfuration separation, copper-containing molten iron is obtained by smelting reduction of copper slag (smelting slag, converting slag, flotation slag, etc.), and the reduced slag is quenched by adjusting the quality and used as cement clinker. After the copper-containing molten iron is directly subjected to vortex sulfuration treatment, copper in the copper-containing molten iron is removed, and copper-rich slag with main component chalcopyrite is obtained, which is used for copper recovery, and the copper-removed molten iron can be directly used for steelmaking, avoiding the influence of copper on the steelmaking process.

[0024] 2. The present application adopts vortex stirring to entrain sulfurizing agent powder into molten iron, which can accelerate the entrainment speed of the composite vulcanizing agent and the vulcanization speed, and realize efficient and rapid sulfuration and separation of copper-containing molten iron.

[0025] 3. The vortex sulfuration furnace provided by the present application is a continuous sulfuration furnace, which has a slag overflow port, and the copper-containing molten iron and the copper-removed molten iron have an inlet and an outlet, so that continuous sulfuration and copper removal of the copper-containing molten iron can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic diagram of the vortex sulfuration furnace of the present application;

[0027] Figure 2 is a flow chart of a method for copper-containing molten iron sulfuration separation of the present application;

[0028] The figure shows that: 1 is a furnace shell, 2 is a slag overflow port, 3 is a coil fixing device, 4 is an induction coil, 5 is a side-blowing lance, 6 is a refractory layer, 7 is a molten iron layer, 8 is a slag layer, 9 is a vortex stirring paddle, 10 is a molten iron inlet chute, 11 is a molten iron outlet, 12 is a heat-insulating layer, and 13 is a bottom-blowing lance. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1

[0031] like Figure 1 As shown, the vortex vulcanizing furnace of the present invention comprises an outer furnace shell 1 and an inner refractory layer 6 in contact with the molten metal. An induction coil 4 for heating is also provided between the furnace shell and the refractory layer. The induction coil is fixed by a coil fixing device 3. A slag overflow port 2, a molten iron inlet chute 10, a molten iron outlet 11, and a blowing port are provided on the side wall of the furnace body. The molten iron inlet chute is located on the upper part of the side wall of the furnace body. The slag overflow port is located above the molten pool surface in the furnace body, that is, above the molten iron layer 7 and at the position of the slag layer 8. The blowing port is located on the side wall and bottom of the furnace body. A side-blowing spray gun 5 and a bottom-blowing spray gun 13 are respectively installed on the blowing port. A vortex stirring paddle 9 is also provided in the furnace body. The vortex stirring paddle includes a stirring paddle shaft and blades disposed thereon. The blades are threadedly connected to the stirring paddle shaft. A heat insulation layer 12 is also provided between the furnace shell and the refractory layer at the bottom of the furnace body.

[0032] In this vortex vulcanizing furnace, the vortex stirring is generated by an agitator or by injected gas. When using an agitator to generate the vortex, the stirring speed is 150 rpm to 400 rpm, and the vulcanizing agent is added directly. When using injected gas to generate the vortex, the vulcanizing agent is added to the molten iron by injection (side blowing or bottom blowing). During the injection process, inert gas is used to carry the vulcanizing agent, and the injected solid content is 5 to 80 kg / Nm³. 3 .

[0033] The vortex sulfidation furnace is a continuous or intermittent sulfidation furnace, equipped with a slag overflow port, a copper-containing molten iron inlet chute, and a copper-removed molten iron outlet, which can realize continuous sulfidation and copper removal of copper-containing molten iron.

[0034] The vortex agitator is made of refractory material, and the blades and agitator shaft are doped with a high-temperature resistant stainless steel skeleton of 1wt.% to 10wt.%.

[0035] The impeller shaft is connected to the motor shaft via a flange sleeve. The flange sleeve includes an upper flange and a lower flange that are bolted together. The upper flange is connected to the motor shaft, and the lower flange is connected to the stainless steel sleeve. The stainless steel sleeve is threaded and is threaded to the impeller shaft, which is threaded to the impeller shaft, which is threaded to the external threads.

[0036] The contact surfaces of the upper and lower flanges are machined into matching concave and convex surfaces to ensure concentricity and prevent the agitator shaft from swaying during mixing.

[0037] The furnace top is further provided with two openable cover plates, which can form a closed space during the operation of the vortex sulfurization furnace without affecting the rotation of the vortex stirring paddle.

[0038] Example 2

[0039] A method for sulfurization separation of copper-containing molten iron based on the device described in Example 1, the flow is shown as follows, comprising the following steps: Figure 2

[0040] Step 1: Using copper-containing flotation copper slag with a copper content of 0.20wt.% to obtain copper-containing molten iron by smelting reduction, the composition of the copper-containing molten iron is as follows: C 3.66wt.%, Cu 0.30wt.%, Si 0.25wt.%, P 0.08wt.%, Zn 0.02wt.%, Mn 0.02wt.%, S 0.43wt.%, and the balance is iron. The reduced slag is quenched with water and used as cement clinker.

[0041] Step 2: Transport the copper-containing molten iron to the vortex sulfurization furnace, which has a slag overflow port, a copper-containing molten iron inlet and outlet, and a vortex stirring paddle made of refractory material. The paddle is doped with 5% high-temperature stainless steel framework.

[0042] Step 3: Using a sulfurizing agent with a particle size of 100μm (sulfurizing agent ratio: pyrite 5wt.%, ferrous sulfide 50wt.%, and elemental sulfur 45wt.%), the sulfurizing agent is sucked downward into the copper-containing molten iron under the action of 200rpm vortex stirring to occur a sulfurization reaction. The sulfurizing agent is added in an amount of 3wt.% of the mass of the copper-containing molten iron, the sulfurization temperature is 1350℃, and the sulfurization time is 120min.

[0043] Step 4: Slag-gold separation, the removal rate of copper in the copper-containing molten iron is 98%, and copper-containing slag with main mineral phase of chalcopyrite is obtained for copper recovery;

[0044] Step 5: The copper content in the copper-removed molten iron is 0.10wt.%, which is directly used for steelmaking.

[0045] Example 3

[0046] A method for sulfurization separation of copper-containing molten iron based on the device described in Example 1, comprising the following steps:

[0047] ​Step 1, copper-containing molten iron is obtained by using copper smelting slag with copper content of 1.21wt.% for molten reduction, the composition of the copper-containing molten iron is as follows in terms of weight percentage: C 2.98wt.%, Cu 2.85wt.%, Si 0.25wt.%, P 0.06wt.%, Zn 0.06wt.%, Mn 0.03wt.%, S 1.16wt.%, and the balance is iron, and the reduction slag is used for cement clinker after water quenching.

[0048] Step 2, the copper-containing molten iron is transported to a vortex sulfuration furnace, which is provided with a slag overflow port, an inlet and an outlet for the copper-containing molten iron and the molten iron after copper removal, and the vortex stirring paddle is made of refractory material, and the paddle and the stirring paddle shaft are doped with 2wt.% high-temperature stainless steel framework.

[0049] Step 3, the sulfuration agent with a particle size of 40μm (sulfuration agent ratio: pyrite 20wt.%, ferrous sulfide 30wt.%, and elemental sulfur 50wt.%) is sucked downward into the copper-containing molten iron under the action of vortex stirring at 300rpm to occur sulfuration reaction, the sulfuration agent is added in an amount of 8wt.% of the mass of the copper-containing molten iron, the sulfuration temperature is 1550℃, and the sulfuration time is 20min.

[0050] Step 4, slag-iron separation is performed, the removal rate of copper in the copper-containing molten iron is 98%, and copper-containing slag with chalcopyrite as the main mineral phase is obtained for copper recovery;

[0051] Step 5, the copper content in the copper-removed molten iron is 0.02wt.%, which is directly used for steelmaking.

[0052] Example 4

[0053] A method for sulfuration separation of copper-containing molten iron based on the device described in Example 1, comprising the following steps:

[0054] Step 1, copper-containing molten iron is obtained by using copper smelting slag with copper content of 1.21wt.% for molten reduction, the composition of the copper-containing molten iron is as follows in terms of weight percentage: C 2.98wt.%, Cu 2.85wt.%, Si 0.25wt.%, P 0.06wt.%, Zn 0.06wt.%, Mn 0.03wt.%, S 1.16wt.%, and the balance is iron, and the reduction slag is used for cement clinker after water quenching.

[0055] Step 2, the copper-containing molten iron is transported to a vortex sulfuration furnace, which is provided with a slag overflow port, an inlet and an outlet for the copper-containing molten iron and the molten iron after copper removal, and the vortex stirring paddle is made of refractory material, and the paddle and the stirring paddle shaft are doped with 2wt.% high-temperature stainless steel framework.

[0056] Step 3, the sulfidation agent (sulfidation agent ratio is pyrite 40wt.%, ferrous sulfide 20wt.%, elemental sulfur 40wt.%) with a particle size of 60μm is sucked downward into the copper-containing molten iron under the action of vortex stirring at 250rpm to occur a sulfidation reaction, the sulfidation agent is added in an amount of 5wt.% of the mass of the copper-containing molten iron, the sulfidation temperature is 1450℃, and the sulfidation time is 60min.

[0057] Step 4, slag-gold separation is performed, the removal rate of copper in the copper-containing molten iron is 99%, and copper-containing slag with a main mineral phase of chalcopyrite is obtained for copper recovery.

[0058] Step 5, the copper content in the copper-removed molten iron is 0.05wt.%, and the copper-removed molten iron is directly used for steelmaking.

[0059] Embodiment 5

[0060] A method for sulfidation separation of copper-containing molten iron based on the device described in Embodiment 1, comprising the following steps:

[0061] Step 1, smelting copper slag with a copper content of 0.56wt.% is used to obtain copper-containing molten iron by molten reduction, and the composition of the copper-containing molten iron is as follows in terms of percentage by weight: C 3.10wt.%, Cu 1.20wt.%, Si 0.10wt.%, P 0.06wt.%, Zn 0.01wt.%, Mn 0.01wt.%, S 0.02wt.%, and the balance is iron, and the reduction slag is quenched by water and used as cement clinker.

[0062] Step 2, the copper-containing molten iron is transported to the vortex sulfidation furnace, which is provided with a slag overflow port and inlet and outlet ports for the copper-containing molten iron and the copper-removed molten iron.

[0063] Step 3, the sulfidation agent (sulfidation agent ratio is pyrite 30wt.%, ferrous sulfide 40wt.%, elemental sulfur 30wt.%) with a particle size of 80μm is sprayed into the copper-containing molten iron in a bottom blowing manner, the sulfidation agent is added in an amount of 8wt.% of the mass of the copper-containing molten iron, the spraying solid content is 40kg / Nm 3 , the sulfidation temperature is 1500℃, and the sulfidation time is 30min.

[0064] Step 4, slag-gold separation is performed, the removal rate of copper in the copper-containing molten iron is 99%, and copper-containing slag with a main mineral phase of chalcopyrite is obtained for copper recovery.

[0065] Step 5, the copper content in the copper-removed molten iron is 0.01wt.%, and the copper-removed molten iron is directly used for steelmaking.

[0066] The above technical solutions set forth the technical idea of the present application, and cannot be used to limit the protection scope of the present application. Any modification and amendment made to the above technical solutions according to the technical essence of the present application, without departing from the technical solutions of the present application, shall fall within the protection scope of the present application.

Claims

1. A method for separating copper-containing molten iron by sulfidation, characterized in that, Includes the following steps: Step 1: Copper slag is molten and reduced to obtain copper-containing molten iron; Step 2: Transfer the copper-containing molten iron to the vortex vulcanizing furnace; Step 3: The vulcanizing agent is drawn into the copper-iron molten metal under the action of vortex stirring to undergo a vulcanization reaction; Step 4: After the reaction, slag and gold are separated to obtain copper-bearing slag with chalcopyrite as the main mineral phase, which is used for copper recovery. Step 5: The copper-removed molten iron remaining after slag-gold separation is directly used for steelmaking; In step 1, the copper content in the copper slag is 0.2 wt.% to 1.21 wt.%. In step 3, the sulfiding agent used is a mixture of pyrite, ferrous sulfide, and elemental sulfur. The ratio of the sulfiding agent is: pyrite 5wt.%~50wt.%, ferrous sulfide 5wt.%~50wt.%, and elemental sulfur 5wt.%~50wt.%. The particle size after grinding is ≤100μm. In step 4, after slag-gold separation, the copper removal rate in the copper-containing molten iron is ≥98%. In step 5, the copper content in the copper-free molten iron is ≤0.10 wt.%.

2. The method for separating copper-containing molten iron by sulfidation according to claim 1, characterized in that, In step 1, the copper slag used includes one or more of the following: smelting slag, blowing slag, and flotation slag.

3. The method for separating copper-containing molten iron by sulfidation according to claim 1, characterized in that, In step 3, the amount of sulfiding agent added is 1wt.%~10wt.% of the mass of copper-containing molten iron, the sulfidation temperature is 1350℃~1550℃, and the sulfidation time is 10min~120min.

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