Vacuum smelting device for antimony concentrate

Abstract

The application provides a vacuum smelting device for antimony concentrate. The vacuum smelting device for antimony concentrate comprises a shell, a program temperature control device and a pressure control device, the inside of the shell is provided with a smelting cavity, and a feeding opening and a pressure control opening are arranged in communication with the smelting cavity, the feeding opening is used for adding cinnabar, reducing fuel and alkaline additives; the program temperature control device is used for controlling the temperature in the smelting cavity in stages; the pressure control device is in communication with the pressure control opening and is used for controlling the vacuum degree in the smelting cavity. The above-mentioned vacuum smelting device is used for extracting metallic antimony from cinnabar, which is beneficial to greatly improving the recovery rate of metallic antimony, simplifying the process flow and reducing the recovery cost.

Description

Technical Field

[0001] The present invention relates to the field of metal smelting, and in particular to a vacuum smelting device for antimony concentrate. Background Art

[0002] The primary phase in stibnite is antimony sulfide (Sb2S3). Stibnite processing techniques are divided into pyrometallurgical and hydrometallurgical processes. Currently, pyrometallurgical processes dominate, with over 95% of stibnite ore produced using pyrometallurgical processes to produce metallic antimony. The typical pyrometallurgical process for stibnite ore production involves smelting in a blast furnace followed by reduction in a reverberatory furnace. During the smelting process, antimony sulfide is volatilized and oxidized, while gangue slag is released from the furnace. The antimony oxide powder obtained from flue gas dust collection is then reduced in a reverberatory furnace to produce crude antimony. While this "blast furnace-reverberatory furnace" process is mature, it still suffers from the following drawbacks:

[0003] Most of the sulfur in stibnite is converted into SO2 and enters the flue gas in the blast furnace, but the concentration in the flue gas is low, the flue gas cannot be used to produce acid, and the flue gas treatment cost is high; the coke rate of the blast furnace is high; the thermal efficiency of the reverberatory furnace process is low, the amount of antimony oxide powder volatilization is large, and the antimony direct recovery rate is low.

[0004] To address the shortcomings of the traditional blast furnace-reverberatory furnace process, various smelting processes and equipment have been developed in this field. These include methods and equipment for producing crude antimony trioxide using oxygen-enriched side-blowing volatile bath smelting, methods and equipment for continuous antimony smelting from stibnite using bottom-blowing bath smelting, side-blowing oxidation smelting and side-blowing reduction smelting of antimony concentrate, and top-blowing bath smelting methods and bath smelting furnaces. All of these smelting methods and equipment generate low-concentration SO2 flue gas, which requires high disposal costs. Summary of the Invention

[0005] The main purpose of the present invention is to provide a vacuum smelting device for antimony concentrate to solve the problems of low antimony metal recovery rate and high cost in the existing stibnite smelting method.

[0006] In order to achieve the above-mentioned objectives, the present invention provides a vacuum smelting device for antimony concentrate, which includes: a shell, a program temperature control device and a pressure control device. A smelting chamber is provided inside the shell, as well as a feeding port and a pressure control port connected to the smelting chamber. The feeding port is used for adding stibnite, reducing fuel and alkaline additives; the program temperature control device is used to control the temperature in the smelting chamber in stages; and the pressure control device is connected to the pressure control port and is used to control the vacuum degree in the smelting chamber.

[0007] In a preferred embodiment, the shell includes: a furnace body and a cover body; the cover body is adapted to the furnace body, and the cover body and the furnace body are movably connected, and the feeding port and the pressure control port are both arranged on the cover body.

[0008] In a preferred embodiment, the cover body is connected to the furnace body via a connecting piece.

[0009] In a preferred embodiment, the antimony concentrate vacuum smelting device further includes an automatic lifting system, which is used to control the opening or closing of the cover.

[0010] In a preferred embodiment, the antimony concentrate vacuum smelting device further includes an automatic control system, which is used to automatically control the pressure control device.

[0011] In a preferred embodiment, an antimony concentrate vacuum smelting apparatus comprises: a bottom plate, a refractory layer, a functional layer, and an electric heating device. The bottom plate is disposed at the bottom of a housing, the refractory layer is disposed on the bottom plate, and the bottom plate and the refractory layer form a smelting chamber; the functional layer is disposed between the refractory layer and the housing body; and the electric heating device is disposed between the functional layer and the housing body.

[0012] In a preferred embodiment, the housing further includes a support member, which is disposed between the bottom plate and the housing body and is used to support the bottom plate.

[0013] In a preferred embodiment, the electric heating device is selected from an induction coil or a heating jacket.

[0014] In a preferred embodiment, the antimony concentrate vacuum smelting device further includes a dust collecting device, which is provided with a flue gas recovery port and a flue dust outlet, the flue gas recovery port is connected to the outlet end of the pressure control device, and the flue dust outlet is connected to the feeding port.

[0015] The technical solution of the present invention controls the vacuum level in the smelting chamber via a pressure control device. This device lowers the pressure of the reaction system below atmospheric pressure, resulting in a correspondingly lower CO2 partial pressure in the product. This facilitates the reaction, thereby increasing the rate of production of antimony-containing products. Furthermore, the programmable temperature control device allows the stibnite to undergo a first vacuum smelting process at a lower temperature, thereby reducing the volatilization rate of the antimony element. The programmable temperature control device then raises the temperature in the smelting chamber, allowing the reaction system to undergo a second vacuum smelting process at a second temperature, yielding crude antimony and slag. Because the antimony element has already been converted to a liquid state during the first vacuum smelting process, volatilization losses are minimal. Therefore, the second vacuum smelting process significantly improves the antimony recovery rate. The entire smelting process takes place within the same smelting chamber, which not only reduces the required floor space and capital investment in the smelting equipment, but also eliminates the steps of discharging and adding the melt, improving production efficiency and reducing the need for operators and associated tools. On this basis, the use of the above-mentioned vacuum smelting device to extract metallic antimony from stibnite is not only conducive to significantly improving the recovery rate of metallic antimony, but also simplifying the process flow and reducing the recovery cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 A schematic structural diagram of an antimony concentrate vacuum smelting device provided according to a preferred embodiment of the present invention is shown.

[0018] The above drawings include the following reference numerals:

[0019] 10. Shell; 11. Cover; 101. Feeding port; 102. Pressure control port; 103. Connector;

[0020] 12. Furnace body; 13. Bottom plate; 14. Refractory layer; 15. Functional layer; 16. Electric heating device; 17. Support member;

[0021] 20. Pressure control device; 30. Dust collection device. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0023] As described in the background technology, the existing stibnite smelting method has the problems of low antimony metal recovery rate and high cost. In order to solve the above technical problems, this application provides an antimony concentrate vacuum smelting device, such as Figure 1 As shown, the antimony concentrate vacuum smelting device includes a housing 10, a programmable temperature control device, and a pressure control device 20. The housing 10 contains a smelting chamber, as well as a feeding port 101 and a pressure control port 102 connected to the smelting chamber. The feeding port 101 is used to add stibnite, reducing fuel, and alkaline additives. The programmable temperature control device is used to control the temperature in the smelting chamber in stages. The pressure control device 20 is connected to the pressure control port 102 to control the vacuum level in the smelting chamber.

[0024] Na2O is selected as the alkaline additive for principle explanation:

[0025] During the alkaline smelting process, stibnite reacts with soda ash and reducing agents as follows:

[0026] 2Sb2S3(s)+6Na2O(s)+3C(s)=4Sb(s)+6Na2S(s)+3CO2(g).

[0027] In the present invention, stibnite is first mixed with a reducing fuel and an alkaline additive and then vacuum smelted to obtain liquid metal antimony, Na2S-rich slag and Sb2S3 flue gas. The Na2S-rich slag can be used to produce Na2S after extraction, and the Sb2S3 flue gas is converted into Sb2S3 after condensation, which can be returned to the vacuum furnace for smelting.

[0028] The vacuum level in the smelting chamber is controlled by a pressure control device 20. Under its action, the pressure of the reaction system is kept below atmospheric pressure, resulting in a correspondingly lower partial pressure of CO2 in the product. This facilitates the reaction to proceed to the right, thereby increasing the rate of production of antimony-containing products. Simultaneously, the programmable temperature control device allows the stibnite to undergo a first vacuum smelting process at a lower temperature, thereby reducing the volatilization rate of the antimony element. The programmable temperature control device then raises the temperature in the smelting chamber, allowing the reaction system to undergo a second vacuum smelting process at a second temperature, yielding metallic antimony and slag. Because the antimony element has already been converted to a liquid state during the first vacuum smelting process, and volatilization losses are minimal, the second vacuum smelting process significantly increases the recovery rate of the antimony element. The entire smelting process is carried out in a single smelting chamber. This not only reduces the required floor space for the smelting process and the capital investment in the smelting equipment, but also eliminates the steps of discharging and adding the melt, improving production efficiency and reducing the need for operators and associated tools. On this basis, the use of the above-mentioned vacuum smelting device to extract metallic antimony from stibnite is not only conducive to significantly improving the recovery rate of metallic antimony, but also simplifying the process flow and reducing the recovery cost.

[0029] In a preferred embodiment, Figure 1 As shown, the shell 10 includes a furnace body 12 and a cover 11 , wherein the cover 11 is adapted to the furnace body 12 , and the cover 11 and the furnace body 12 are movably connected, and the feeding port 101 and the pressure control port 102 are both provided on the cover 11 .

[0030] Dividing the shell 10 into two movably connected parts can improve the convenience of material transfer after the reaction is completed, and arranging the feeding port 101 on the cover 11 can preheat the added reaction raw materials in the process of falling into the smelting chamber, which is beneficial to improving the smelting efficiency and the recovery rate of antimony metal.

[0031] The cover 11 of the housing 10 and the furnace body 12 are movably connected and can adopt a common connection method in the art, such as being connected through a connector 103. Preferably, the connector 103 includes but is not limited to a flange.

[0032] In order to improve the convenience of opening and closing the cover 11 , preferably, the antimony concentrate vacuum smelting device further includes an automatic lifting system, which is used to control the opening or closing of the cover 11 .

[0033] In a preferred embodiment, the antimony concentrate vacuum smelting apparatus further includes an automatic control system for automatically controlling the pressure control device 20. Controlling the pressure control device 20 through the automatic control system enables more precise control of the pressure in the smelting chamber, thereby further improving the recovery rate of the antimony element.

[0034] In a preferred embodiment, Figure 1 As shown, the housing 10 comprises: a housing 10 body, a bottom plate 13, a refractory layer 14, and a functional layer 15. The bottom plate 13 is disposed at the bottom of the housing 10 body, and the refractory layer 14 is disposed on the bottom plate 13. The bottom plate 13 and the refractory layer 14 form a smelting chamber. The functional layer 15 comprises a filler material and an electric heating device 16, and is disposed between the refractory layer 14 and the housing 10 body. The above-mentioned antimony concentrate vacuum smelting apparatus can provide heat to the smelting chamber through fuel combustion or through the electric heating device 16. More preferably, the electric heating device 16 includes, but is not limited to, an induction coil or a heating jacket, and the refractory layer 14 includes, but is not limited to, refractory materials such as magnesia-carbon bricks, magnesia-chrome bricks, magnesia-carbon bricks, and magnesia-alumina bricks.

[0035] In a preferred embodiment, Figure 1 As shown, the housing 10 further includes a support member 17, which is disposed between the bottom plate 13 and the main body of the housing 10 and is used to support the bottom plate 13. Providing the support member 17 between the bottom plate 13 and the main body of the housing 10 helps improve the thermal insulation performance of the smelting chamber, thereby enabling the heat to be fully utilized in the smelting process of the reaction materials, thereby improving the heat utilization rate and the recovery rate of the antimony element.

[0036] In a preferred embodiment, Figure 1 As shown, the antimony concentrate vacuum smelting device further includes a dust collecting device 30 , which is provided with a fume recovery port and a fume dust outlet. The fume recovery port is connected to the outlet end of the pressure control device 20 , and the fume dust outlet is connected to the feeding port 101 .

[0037] Antimony-containing dust is generated during vacuum smelting. Connecting the dust collecting device 30 with the outlet end of the pressure control device 20 can recover the antimony-containing dust. Connecting the dust outlet with the feeding port 101 can return the recovered dust to the smelting chamber for reuse.

[0038] The pressure control device 20 can be any commonly used device in the art, preferably a vacuum pump. More preferably, the vacuum smelting apparatus includes two pressure control devices 20, two dust collectors 30, and two rotating connectors 103. Providing two pressure control devices 20 facilitates more precise control of the pressure in the smelting chamber, while providing two dust collectors 30 improves dust collection efficiency. Providing two rotating connectors 103 facilitates easier unloading of the vacuum smelting apparatus.

[0039] Another aspect of the present application also provides a smelting method of stibnite, which is carried out by using the device as shown in the figure, and the smelting method comprises: under vacuum conditions, carrying out first vacuum smelting and second vacuum smelting of stibnite, reducing fuel and alkaline additive respectively in the vacuum smelting device to obtain metallic antimony and slag, and the temperature of the first vacuum smelting is lower than that of the second vacuum smelting. Figure 1

[0040] The vacuum degree in the smelting cavity is controlled by the pressure control device 20, and under the action of the pressure control device 20, the pressure of the reaction system is lower than the atmospheric pressure, and correspondingly, the partial pressure of CO2 gas in the product is also relatively low. This makes the above reaction more easily proceed to the right, thereby being conducive to improving the generation speed of the antimony-containing product. At the same time, the stibnite is subjected to the first vacuum smelting process at a lower temperature, which can also reduce the volatilization rate of the antimony element. Then the temperature in the smelting cavity is raised by the program temperature control device, so that the reaction system is subjected to the second vacuum smelting process at a second temperature to obtain metallic antimony and slag. Since the antimony element has been converted into a liquid state and has less volatilization loss in the first vacuum smelting process, the recovery rate of the antimony element can be greatly improved through the second vacuum smelting process. The entire smelting process is carried out in the same smelting cavity, which on the one hand makes the required land area of the above smelting process small, reduces the capital investment in the smelting device; on the other hand, it can also save the operation steps of smelting discharge and addition, improve the production operation efficiency, and reduce the consumption of operating personnel and corresponding tools and instruments. On this basis, using the above-mentioned vacuum smelting device to extract metallic antimony from stibnite is not only conducive to greatly improving the recovery rate of metallic antimony, but also simplifying the process flow and reducing the recovery cost.

[0041] In a preferred embodiment, the amount of reducing fuel is 8-20% by weight percentage of stibnite, and the amount of alkaline additive is 60-100% by weight percentage of stibnite. The amount of reducing material and alkaline additive includes but is not limited to the above range, and limiting it in the above range is conducive to further improving the recovery rate of the antimony element.

[0042] In a preferred embodiment, the amount of binder is 0.2-15% by weight percentage of stibnite. The amount of binder includes but is not limited to the above range, and limiting it in the above range is conducive to further improving the adhesion of stibnite, reducing agent and alkaline additive, thereby being conducive to improving the recovery rate of the antimony element. More preferably, the amount of binder is 3-8% by weight percentage of stibnite.

[0043] ​Using the above vacuum smelting method to smelt stibnite significantly improves the recovery rate of antimony while minimizing sulfur loss. In a preferred embodiment, the temperature of the first vacuum smelting is 500-700°C, and the temperature of the second vacuum smelting is 1000-1200°C, with a pressure of 0-50 Pa. Limiting the temperature and pressure of the vacuum smelting and separation processes to these ranges further improves the recovery rate of antimony compared to other ranges.

[0044] In a preferred embodiment, prior to vacuum smelting, the vacuum smelting method further comprises: granulating the binder and the crushed stibnite, the reducing fuel, and the alkaline additive to produce a mixture; and sequentially subjecting the mixture to a first vacuum smelting and a second vacuum smelting to produce metallic antimony, slag, and antimony-containing flue gas. Granulating the stibnite, reducing fuel, alkaline additive, and binder prior to vacuum smelting allows the reactants to react in a specific ratio and improves mixing uniformity, thereby facilitating improved recovery of metallic antimony.

[0045] In a preferred embodiment, the vacuum smelting method further comprises crushing the stibnite, reducing fuel, and alkaline additive prior to the pelletizing process. To ensure a more complete reaction of the raw materials during the vacuum smelting process, the particle size of the stibnite, reducing fuel, and alkaline additive after the crushing step is preferably 10-2000 mesh, and even more preferably, the particle size of the stibnite, reducing fuel, and alkaline additive is 200-1000 mesh.

[0046] In a preferred embodiment, the mixed material is spherical with a diameter of 0.1 to 5 cm. Forming the spherical structure during the granulation process, and limiting the diameter to the above range, further enhances the degree of reaction and, in turn, the recovery rate of the antimony element. More preferably, the diameter of the mixed material is 0.2 to 1 cm.

[0047] To ensure a more complete reaction of the raw materials during vacuum melting, in a preferred embodiment, the vacuum melting method further comprises drying the mixture obtained from the granulation process between the granulation process and the vacuum melting process. More preferably, the drying process includes, but is not limited to, natural ventilation or heating dehydration.

[0048] The reducing fuel used in the vacuum smelting process can be any of those commonly used in the art. In a preferred embodiment, the reducing fuel includes one or more of the group consisting of anthracite, bituminous coal, graphite, carbonaceous materials, petroleum coke, coke, and activated carbon.

[0049] In a preferred embodiment, the alkaline additive includes but is not limited to sodium carbonate and / or sodium hydroxide.

[0050] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0051] Example 1

[0052] A method for smelting antimony metal, using a vacuum melting device such as Figure 1 As shown, the smelting method includes:

[0053] After uniformly mixing 1 ton of antimony concentrate, soda ash (the added amount accounts for 70% of the antimony concentrate), and carbon powder (the added amount accounts for 6% of the antimony concentrate), a binder (water, the added amount accounts for 5% of the total weight of the antimony concentrate, soda ash and carbon powder) is added to form briquettes or pellets; a weighed amount of crude antimony as a bottom material is placed on the bottom plate 13 of the antimony concentrate vacuum smelting device, and then the above briquettes or pellets are dried and placed on top of the crude antimony.

[0054] The smelting chamber is evacuated using a pressure control device 20 (vacuum pump) to a pressure of 50 Pa. The electric heating device 16 (induction coil) is then activated to heat the material in the furnace to 700°C. A first smelting process is performed at this temperature for one hour. The temperature is then raised to 1150°C, where a second smelting process is performed for one hour. The particle size of the stibnite, carbon powder, and industrial soda ash is all 200 mesh.

[0055] After the smelting of the first batch of materials is completed, the second batch of materials is added, and the antimony sulfide dust recovered from the smelting of the previous batch of materials is used for the smelting of the next batch. After the antimony liquid in the crucible is filled, the air extraction is stopped, the cover 11 is removed, and then the furnace body 12 is rotated by the rotating device to pour the antimony liquid in the crucible into the container, thereby completing the smelting of one batch of antimony concentrate.

[0056] After the antimony concentrate is smelted by the vacuum smelting device of the present invention, the direct antimony recovery rate is 65.3%, the total antimony recovery rate is 99.2%, and the crude antimony smelted product has a high purity, containing only 0.13% iron, 0.04% As, and 0.05% S.

[0057] Comparative Example 1

[0058] The difference from Example 1 is:

[0059] The antimony concentrate vacuum smelting device is not provided with a program temperature control device. A smelting method of antimony metal includes:

[0060] After uniformly mixing 1 ton of antimony concentrate, soda ash (the added amount accounts for 70% of the antimony concentrate), and carbon powder (the added amount accounts for 6% of the antimony concentrate), a binder (water, the added amount accounts for 5% of the total weight of the antimony concentrate, soda ash and carbon powder) is added to form briquettes or pellets; a weighed amount of crude antimony as a bottom material is placed on the bottom plate 13 of the antimony concentrate vacuum smelting device, and then the above briquettes or pellets are dried and placed on top of the crude antimony.

[0061] The smelting chamber is evacuated using a pressure control device 20 (vacuum pump) to a pressure of 50 Pa. The electric heating device 16 (induction coil) is then activated to heat the material in the furnace to 1150°C. The vacuum smelting process is then carried out at this temperature for 2 hours. The particle size of the stibnite, carbon powder, and industrial soda ash is all 200 mesh.

[0062] The direct recovery rate of antimony is 46.5%, the total antimony recovery rate is 91.6%, and the crude antimony product of the smelting product has a high purity, containing 0.14% iron, 0.05% As, and 0.06% S.

[0063] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: compared with the existing smelting device, the use of the above-mentioned vacuum smelting device to extract metallic antimony from stibnite is not only conducive to significantly improving the recovery rate of metallic antimony, but also simplifying the process flow and reducing the recovery cost.

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A vacuum smelting device for antimony concentrate, characterized in that: The antimony concentrate vacuum smelting device comprises: A shell (10), wherein a smelting chamber is provided inside the shell (10), and a feeding port (101) and a pressure control port (102) are provided in communication with the smelting chamber, wherein the feeding port (101) is used for adding stibnite, reducing fuel and alkaline additive; A programmable temperature control device, which is used to control the temperature in the smelting chamber in stages; a pressure control device (20), the pressure control device (20) being in communication with the pressure control port (102) and being used to control the vacuum degree in the smelting chamber; The antimony concentrate vacuum smelting device further comprises a dust collecting device (30), wherein the dust collecting device (30) is provided with a fume recovery port and a fume dust outlet, wherein the fume recovery port is communicated with the outlet end of the pressure control device (20), and the fume dust outlet is communicated with the feeding port (101); A bottom plate (13), the bottom plate (13) being arranged at the bottom of the housing (10); a refractory layer (14), the refractory layer (14) being arranged on the bottom plate (13), and the bottom plate (13) and the refractory layer (14) forming the smelting chamber; a functional layer (15), the functional layer (15) being arranged between the fire-resistant layer (14) and the main body of the shell (10); and an electric heating device (16), the electric heating device (16) being arranged between the functional layer (15) and the main body of the housing (10); The housing (10) further comprises a support member (17), wherein the support member (17) is arranged between the bottom plate (13) and the main body of the housing (10) and is used to support the bottom plate (13); The invention discloses a method for smelting stibnite using the antimony concentrate vacuum smelting device. The method comprises: under vacuum conditions, performing a first vacuum smelting and a second vacuum smelting on stibnite, a reducing fuel and an alkaline additive in the antimony concentrate vacuum smelting device to obtain metallic antimony and slag, wherein the temperature of the first vacuum smelting is lower than that of the second vacuum smelting; the temperature of the first vacuum smelting is 500-700°C, and the temperature of the second vacuum smelting is 1000-1200°C.

2. The antimony concentrate vacuum smelting device according to claim 1, characterized in that: The housing (10) comprises: a furnace body (12); and A cover body (11), wherein the cover body (11) is adapted to the furnace body (12), and the cover body (11) and the furnace body (12) are movably connected, and the feeding port (101) and the pressure control port (102) are both provided on the cover body (11).

3. The antimony concentrate vacuum smelting device according to claim 2, characterized in that: The cover body (11) and the furnace body (12) are connected via a connecting piece (103).

4. The antimony concentrate vacuum smelting device according to claim 2, characterized in that: The antimony concentrate vacuum smelting device further comprises an automatic lifting system, and the automatic lifting system is used to control the opening or closing of the cover body (11).

5. The antimony concentrate vacuum smelting device according to claim 4, characterized in that: The antimony concentrate vacuum smelting device further comprises an automatic control system, which is used to automatically control the pressure control device (20).

6. The antimony concentrate vacuum smelting device according to claim 1, characterized in that: The electric heating device (16) is selected from an induction coil or a heating jacket.

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