Method for reducing antimony oxide powder by using side-blown converter

Abstract

The invention belongs to the technical field of non-ferrous metallurgy, and particularly discloses a method for reducing antimony oxide powder through a side-blown converter. Antimony oxide powder and lump coal are mixed, water is added for granulation after mixing, and pellet aggregates with the lump coal as a pellet core and the outer layer wrapped with wet antimony oxide powder are obtained; the obtained pellet aggregates are put into a side-blown furnace, meanwhile, a slag former is put into the side-blown furnace, oxygen-enriched compressed air and water vapor are introduced into the side-blown furnace, and a heating melting reduction smelting reaction is conducted in a molten pool of the side-blown furnace; crude antimony and soaking slag are produced after the reaction, and the soaking slag is discharged out of the system as waste slag; and in the reaction process, the generated process flue gas is returned through secondary oxygen powder produced by dust collection for mixing, water adding and granulation, and the tail gas discharged after dust collection is subjected to environmental protection treatment and then is emptied. By adopting the method for reducing the antimony oxide powder, the direct recovery rate of antimony is larger than or equal to 86%, and compared with the direct recovery rate of 81-85% of reduction smelting of the antimony oxide powder in a traditional process, the direct recovery rate of antimony is improved by 1-2%.

Description

1. Technical field:

[0001] The invention belongs to the technical field of nonferrous metal metallurgy, and in particular relates to a method for reducing antimony oxide powder by using a side-blown furnace. 2. Background technology:

[0002] Fire-metallurgical antimony smelting generally adopts the oxidation volatilization-reduction smelting method, that is, the antimony-containing material is put into the metallurgical furnace for high-temperature oxidation volatilization, the elemental antimony in the antimony-containing material is oxidized to Sb2O3, and the product antimony oxide powder is volatilized and produced, and then the antimony oxide powder is put into the metallurgical furnace for reduction smelting to produce crude antimony. At present, the most commonly used reduction smelting process is antimony oxide powder reverberatory furnace reduction, that is, antimony oxide powder, reducing coal and flux are mixed in proportion in the batching system, and then added to the reverberatory furnace, and reduced at a high temperature of 900-1200°C to produce crude antimony. The reduction smelting process includes multiple processes such as feeding, melting and reduction, and slag removal. The antimony-containing flue gas generated in the melting and reduction process is returned to the reverberatory furnace for reduction smelting again after dust collection, and the antimony-containing slag generated in the slag removal process is returned to the volatilization smelting process.

[0003] The traditional antimony oxide reverberatory furnace reduction process uses reverberatory furnace process equipment. The reverberatory furnace has poor airtightness, and the escape of flue gas and smoke causes the loss of valuable metals and pollutes the production environment. The reverberatory furnace production mode uses upper surface heating of the molten pool, and the molten pool lacks necessary stirring, resulting in poor heat and mass transfer of the charge, low smelting intensity, and low production efficiency. The reverberatory furnace process equipment furnace wall is built with refractory bricks, and the furnace body has a large heat dissipation, resulting in low thermal utilization rate of the reverberatory furnace production. A large amount of fuel coal or natural gas is consumed in the production process to provide the required temperature for the reduction reaction, resulting in high energy consumption.

[0004] At present, there are also relevant patent documents reporting on the production of metallic antimony by reduction of antimony-containing materials. For example, the invention patent application CN202011080046.0 discloses a method for producing metallic antimony from antimony oxide powder. The method mixes antimony oxide powder, a reducing agent and a flux evenly, granulates to obtain pellets or briquettes, and sends the obtained pellets or briquettes to an electromagnetic induction device or a microwave device for reduction smelting to obtain crude antimony, slag and antimony oxide smoke. The method uses soda ash as a flux and adopts the process principle of making alkaline slag; the process equipment used is an electromagnetic induction device and a microwave device to heat the material, and the returned slag is used as a smelting covering agent, and the reducing agent uses at least one of activated carbon or charcoal powder. The method is a process method for intermittent production in separate furnaces. 3. Summary of the invention:

[0005] The technical problem to be solved by the present invention is: in view of the many problems in the traditional process of antimony oxide reduction smelting, such as high energy consumption, great environmental pollution, and low production efficiency, the present invention provides a method for reducing antimony oxide powder using a side-blown furnace. The antimony oxide powder is reduced by the technical scheme of the present invention, and its antimony direct recovery rate is ≥86%, which is 1-2% higher than the antimony direct recovery rate of 81-85% in the traditional process of antimony oxide powder reduction smelting.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] The present invention provides a method for reducing antimony oxide powder by using a side-blown furnace, the method comprising the following steps:

[0008] a. Mixing antimony oxide powder with lump coal, adding water to granulate after mixing, and obtaining pelletized granules with lump coal as the core and wet antimony oxide powder wrapped on the outer layer;

[0009] b. The obtained pelletized material is put into a side-blown furnace, and a slag-making agent is added at the same time, and oxygen-enriched compressed air and water vapor are introduced into the side-blown furnace (through the submerged tuyeres at the bottom of the side-blown furnace molten pool or the gas spray gun), and the temperature is increased in the side-blown furnace molten pool for melting, reduction and smelting reaction; crude antimony and foaming slag are produced after the reaction, and the foaming slag is used as a waste slag discharge system;

[0010] c. During the reaction, the process flue gas generated is dust-collected and the sub-oxygen powder produced is returned to step a for mixing and granulation with water. The tail gas discharged after dust collection is discharged after environmental protection treatment.

[0011] According to the above method of reducing antimony oxide powder by using a side-blown furnace, when the antimony oxide powder is mixed with lump coal in step a, the weight ratio of the antimony oxide powder to the lump coal is 100:4-45.

[0012] According to the above method of reducing antimony oxide powder by using a side-blown furnace, the moisture content of the pellets obtained in step a is 2-16%; the particle size of the pellets obtained is 10-300 mm.

[0013] According to the above-mentioned method of reducing antimony oxide powder using a side-blown furnace, the slag-forming agent in step b is at least one of iron ore, quartz and stone; the slag-forming agent is added in accordance with the principle that the weight percentage of the three components of iron, silicon and calcium in the foam slag produced thereby is FeO 25-38%, SiO2 20-28% and CaO 5-18%.

[0014] According to the above method of reducing antimony oxide powder by using a side-blown furnace, the gas pressure when the oxygen-enriched compressed air is introduced in step b is 0.1-0.5 MPa, and the oxygen-enriched concentration is 21-90%; the ratio of the volume of oxygen introduced in the oxygen-enriched compressed air to the total weight of the pelletized particles and the slag-making agent put into the side-blown furnace is 90-150 Nm 3 / t.

[0015] According to the above method of reducing antimony oxide powder using a side-blown furnace, the water vapor in step b is the water vapor produced by the waste heat boiler of the metallurgical furnace.

[0016] According to the above method of reducing antimony oxide powder using a side-blown furnace, the gas pressure of water vapor introduced into the side-blown furnace is 0.1-0.5 MPa, and the temperature of the water vapor is ≥100°C.

[0017] According to the above method of reducing antimony oxide powder using a side-blown furnace, the volume ratio of the water vapor and the oxygen-enriched compressed air added is 1-40:100.

[0018] According to the above method of reducing antimony oxide powder using a side-blown furnace, during the reduction smelting reaction in step b, the temperature of the molten pool in the furnace is controlled to be 900-1300°C.

[0019] According to the above-mentioned method of reducing antimony oxide powder using a side-blown furnace, in step b, the side-blown furnace adopts continuous feeding, and the produced crude antimony and foaming slag are discharged from the furnace regularly; among the added materials, the pelletized granular materials adopt a continuous feeding mode, and the slag-forming agent adopts a continuous feeding mode or an irregular intermittent feeding mode.

[0020] The main raw material antimony oxide powder used in the present invention can be applied to the method of the present invention if the antimony content is ≥ 0%.

[0021] In the technical solution of the present invention, the relevant physical and chemical reaction processes carried out in the molten pool of the side-blown furnace are as follows:

[0022] Antimony oxide powder is the main material of the method of the present invention. When heated in a side-blown furnace, it realizes various physical and chemical processes such as heating, dehydration, melting, reduction reaction and sedimentation separation. Finally, antimony oxide is converted into a crude antimony alloy product mainly composed of metallic antimony and mixed with other metal elements. The gangue and impurity components in the antimony oxide powder are mixed or combined with a slag-making agent to be converted into a reducing slag. The reducing slag is filled with various bubbles after being produced under the action of the side-blown furnace gas, and the structure is relatively fluffy, so it is called foam slag.

[0023] The lump coal entering the furnace is used as both fuel and reducing agent, and is also used as a raw material for water gas reaction with water vapor. Most of the lump coal in the molten pool in the furnace floats on the upper surface of the molten pool due to its light specific gravity, and a small part of the lump coal is immersed in the high-temperature molten pool under the violent stirring of the molten pool by the high-pressure gas entering the furnace from the side blowing tuyere or gas spray gun. A part of the lump coal burns with the oxygen-rich compressed air entering the furnace to generate heat, providing guarantee for the heating and melting of the materials entering the furnace and ensuring that the molten pool has sufficient fluidity, and a part of the lump coal and the oxygen-rich compressed air entering the furnace are not fully burned to generate reducing gas CO, CO and part of the high-temperature hot reducing coal play a reducing role in the molten pool, reducing the metal oxides mainly composed of antimony oxides to metal mixtures mainly composed of metallic antimony, generating crude antimony alloys, which are precipitated and separated at the bottom of the molten pool due to their large specific gravity. When the crude antimony alloy layer accumulates to a sufficient amount, it is regularly siphoned out of the side blowing furnace and cast into crude antimony alloy ingots as the product output of the method of the present invention.

[0024] At the same time, the high-temperature, high-pressure water vapor entering the furnace through the side-blowing tuyere or the side-blowing gas spray gun contacts the hot lump coal in the furnace, producing a water-gas reaction to generate reducing gases CO and H2. CO and H2 also play a reducing role in the molten pool, reducing the metal oxides mainly composed of antimony oxides to a metal mixture mainly composed of metallic antimony, so that a crude antimony alloy is generated in the molten pool. In the method of the present invention, the hot lump coal, the CO produced by the incomplete combustion of the lump coal, and the CO and H2 generated by the reaction of the lump coal with water vapor and water gas all play a reducing role. Various reducing agents from different sources complement each other to jointly achieve the purpose of the antimony oxide powder reduction process.

[0025] In the technical solution of the present invention, the use of high-temperature and high-pressure water vapor brings related effects to the method of the present invention: 1) the amount of gas entering the furnace is increased, and the stirring intensity in the molten pool is increased; 2) the amount of gas entering the furnace is increased, so that more bubbles are dissolved in the reduced slag, the specific gravity of the reduced slag is reduced, the sedimentation and separation effect of the valuable metals contained in the slag is optimized, and the slag contains valuable metal indicators; 3) after the water vapor enters the molten pool, it first shows its oxidizing property, and the CO and H2 produced after the water-gas reaction show their reducing property, react and mix with different components in the charge, effectively realize the heat and mass transfer process of the materials in the molten pool, increase the reaction intensity, and accelerate the reaction process.

[0026] In addition, the gangue and other impurities in the charge are converted into foamed slag along with the slag-making agent.

[0027] The crude antimony produced by the method of the present invention can be sold as a product, or further refined to produce a refined antimony product of better quality. The foam slag has a low content of valuable metals and has no further recovery value, so it is discarded as the waste slag of the method of the present invention.

[0028] In the smelting reaction process of the present invention, the main chemical reaction equation is as follows:

[0029] C+O2=CO2;

[0030] 2C+O2=2CO;

[0031] C+H2O=CO+H2;

[0032] 2Sb2O3+3C=4Sb+3CO2;

[0033] Sb2O3+3CO=2Sb+3CO2;

[0034] Sb2O3+3H2=2Sb+3H2O;

[0035] FeO+SiO2=FeO·SiO2;

[0036] CaO+SiO2=CaO·SiO2.

[0037] The positive beneficial effects of the present invention are:

[0038] 1. In the reduction smelting process of the present invention, a side-blown furnace is used to replace metallurgical process equipment such as a blast furnace and a reverberatory furnace used in the traditional process. The advantages of the side-blown furnace such as high smelting intensity, strong raw material applicability, good airtightness, high heat utilization rate, and friendly working environment are fully utilized.

[0039] 2. The technical solution of the present invention is that during the reduction smelting process in the side-blown furnace, oxygen-enriched compressed air and high-temperature and high-pressure water vapor are introduced into the furnace through an submerged gas spray gun. The gas entering the furnace plays a good stirring role in the molten pool, so that the various phases in the molten pool are fully stirred and mixed, and various physical and chemical reactions in the molten pool can be fully realized.

[0040] 3. During the molten pool smelting process of the present invention, the presence of a fixed floating coal layer on the upper surface of the molten pool in the furnace causes part of the gasified antimony oxides in the molten pool to float up and penetrate the molten pool and then be reduced and returned to the molten pool by the floating coal layer, which effectively prevents the gasified antimony oxides from penetrating the molten pool into the process dust, thereby improving the direct recovery rate of antimony.

[0041] 4. In the technical solution of the present invention, after the high-temperature and high-pressure water vapor enters the molten pool in the side-blown furnace through the side-blowing tuyere or the gas spray gun, the molten pool is fully stirred, which effectively increases the stirring intensity of the molten pool, accelerates the full and uniform mixing of various materials, and accelerates the heat transfer and reaction process; in addition, water vapor has strong oxidizing properties at high temperatures, and the CO and H2 produced after the water-gas reaction is completed have strong reducing properties. The change in the properties before and after the chemical reaction effectively accelerates the heat and mass transfer between the components in the molten pool and the full progress of the chemical reaction, thereby achieving enhanced smelting and improving the reduction smelting efficiency.

[0042] 5. In the technical solution of the present invention, the high-temperature and high-pressure steam used is the steam produced by the waste heat boilers of other metallurgical furnaces, which is a by-product of waste heat recovery and utilization. Except for the setting of steam pipelines, no additional production costs are added.

[0043] 6. In the technical solution of the present invention, because high-temperature and high-pressure water vapor is introduced into the furnace through the side-blowing tuyere or the gas spray gun, the proportion of the gas phase components in the molten pool is increased, and the pores in the produced reduction slag are dense, which effectively reduces the proportion of the reduction slag. The sedimentation and separation of the alloy layer, the reduction slag layer, and the lump coal layer from bottom to top in the molten pool are more thorough, the slag contains low valuable metals, and the direct metal recovery rate of the method of the present invention is improved.

[0044] 7. In the technical solution of the present invention, powdered antimony oxide powder is added with water and granulated with lump coal to form agglomerates and pellets, which are then put into the furnace. On the one hand, this prevents the powdered material from being directly put into the furnace and discharged with the process flue gas without reacting, causing material loss. On the other hand, after the lump coal wrapped by the wet material is put into the molten pool in the furnace, the lump coal is exposed to participate in the reaction only after the reaction of the outer layer of material is completed. This effectively avoids the loss of lump coal due to premature combustion, saves the use of lump coal, and reduces production costs.

[0045] 8. In the technical solution of the present invention, lump coal is used as both a fuel and a reducing agent, replacing expensive metallurgical coke, natural gas, etc. used in traditional processes, thereby reducing production costs.

[0046] In summary, by adopting the technical scheme of the present invention, the direct recovery rate of antimony from the reduction smelting of antimony oxide powder in the traditional process can reach 81-85%, and the direct recovery rate of antimony in the process method of the present invention can be increased by 1-2% compared with the traditional process, and its direct recovery rate of antimony is ≥86%. 4. Description of the drawings:

[0047] Figure 1 A schematic diagram of the process flow of the method for reducing antimony oxide powder by using a side-blown furnace according to the present invention. V. Specific implementation methods:

[0048] The present invention is further described below in conjunction with embodiments, but the protection scope of the technical solution of the present invention is not limited thereto.

[0049] Embodiment 1:

[0050] The method for reducing antimony oxide powder using a side-blown furnace of the present invention comprises the following detailed steps:

[0051] a. Set the processing capacity of antimony oxide powder to 10 t / h (the components and contents of the antimony oxide powder are detailed in Table 1), add lump coal according to the coal blending ratio of 100:25, and the weight of the lump coal added is 2.5 t / h; mix the antimony oxide powder with the lump coal, add water at 670 kg / h, and make pellets in a pelletizer with lump coal as the core and wet antimony oxide powder as the outer layer;

[0052] Table 1 Components and contents of antimony oxide powder used in Example 1 of the present invention

[0053]

[0054] b. The obtained pelletized material is continuously fed into the side-blowing furnace using a belt feeding mode. According to the content of iron in the raw materials and the content of effective components (SiO2, CaO) in quartz and stone, it is calculated that the quartz and stone fed into the side-blowing furnace are 140Kg / hh and 88Kg / h respectively; and 2200Nm of oxygen-enriched compressed air is introduced into the side-blowing furnace through the side-blowing gas spray gun at the bottom of the side-blowing furnace. 3 / h (oxygen enrichment concentration is 60%, gas pressure is 0.3MPa), and at the same time, 440Nm of water vapor with a temperature of 110°C and a pressure of 0.3MPa is sprayed into the furnace through the spray gun. 3 / h, the temperature is raised in the side-blown furnace molten pool for melting reduction smelting reaction, and the temperature of the molten pool in the side-blown furnace is 1150°C during the reaction; after the reaction, when the liquid level in the molten pool in the side-blown furnace is high enough, the crude antimony alloy is siphoned out irregularly, and the foaming slag is discharged regularly; the crude antimony is sold as a product or further refined and purified, and the foaming slag is discarded as waste slag;

[0055] After the reaction, 6t / h of crude antimony alloy was produced, the alloy contained 96.5% antimony, and the direct antimony recovery rate was 87.04%; 0.58t / h of foaming slag was produced, and the foaming slag contained 29.5% FeO, 26.3% SiO2, and 8.5% CaO;

[0056] c. During the reaction, the process flue gas generated is dust-collected and the sub-oxygen powder produced is returned to step a for mixing and granulation with water. The tail gas discharged after dust collection is discharged after environmental protection treatment.

[0057] Embodiment 2:

[0058] The method for reducing antimony oxide powder using a side-blown furnace of the present invention comprises the following detailed steps:

[0059] a. Set the processing capacity of antimony oxide powder to 10 t / h (the various components and their contents in the antimony oxide powder are detailed in Table 2), add lump coal according to the coal blending ratio of 100:30, and the weight of the lump coal added is 3 t / h; mix the antimony oxide powder with the lump coal, add water at a rate of 600 kg / h, and make pellets in a pelletizer with the lump coal as the core and the wet antimony oxide powder as the outer layer;

[0060] Table 2 Components and contents of antimony oxide powder used in Example 2 of the present invention

[0061]

[0062] b. The obtained pelletized material is continuously fed into the side-blowing furnace using a belt feeding mode. According to the content of iron in the raw materials and the content of effective components (SiO2, CaO) in quartz and stone, the quartz and stone fed into the side-blowing furnace are calculated to be 4 kg / h and 450 kg / h respectively, and 2000 Nm of oxygen-enriched compressed air is introduced into the side-blowing furnace through the side-blowing gas spray gun at the bottom of the side-blowing furnace. 3 / h (oxygen enrichment concentration is 70%, gas pressure is 0.3MPa), and at the same time, 500Nm2 of water vapor with a temperature of 150°C and a pressure of 0.3MPa is sprayed into the furnace through a spray gun. 3 / h, the temperature is raised in the side-blown furnace molten pool for melting reduction smelting reaction, and the temperature of the molten pool in the side-blown furnace is 1150°C during the reaction; after the reaction, when the liquid level in the molten pool in the side-blown furnace is high enough, the crude antimony alloy is siphoned out irregularly, and the foaming slag is discharged regularly; the crude antimony is sold as a product or further refined and purified, and the foaming slag is discarded as waste slag;

[0063] After the reaction, 1.5t / h of crude antimony alloy was produced, the alloy contained 69.2% antimony, and the antimony direct recovery rate was 86.1%; 8.4t / h of foaming slag was produced, and the foaming slag contained 32.1% FeO, 25.7% SiO2, and 13.6% CaO;

[0064] c. During the reaction, the process flue gas generated is dust-collected and the sub-oxygen powder produced is returned to step a for mixing and granulation with water. The tail gas discharged after dust collection is discharged after environmental protection treatment.

Claims

1. A method for reducing antimony oxide powder using a side-blown furnace, characterized in that: The method comprises the following steps: a. Mixing antimony oxide powder with lump coal, adding water to granulate after mixing, and obtaining pelletized granules with lump coal as the core and wet antimony oxide powder wrapped on the outer layer; b. The obtained pelletized material is put into a side-blown furnace, a slag-making agent is added at the same time, and oxygen-enriched compressed air and water vapor are introduced into the side-blown furnace, and a temperature-raising, melting, reduction and smelting reaction is carried out in the molten pool of the side-blown furnace; crude antimony and foaming slag are produced after the reaction, and the foaming slag is used as a waste slag discharge system; c. During the reaction, the process flue gas generated is dust-collected and the sub-oxygen powder produced is returned to step a for mixing and granulation with water. The tail gas discharged after dust collection is discharged after environmental protection treatment.

2. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: When the antimony oxide powder and the lump coal are mixed in step a, the weight ratio of the antimony oxide powder to the lump coal is 100:4-45.

3. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: The moisture content of the pellets obtained in step a is 2-16%; the particle size of the pellets obtained is 10-300 mm.

4. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: The slag-forming agent in step b is at least one of iron ore, quartz and gravel; the principle of adding the slag-forming agent is: the weight percentage of the three components of iron, silicon and calcium in the foam slag produced is FeO 25-38%, SiO2 20-28% and CaO 5-18%.

5. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: The gas pressure of the oxygen-enriched compressed air when introduced in step b is 0.1-0.5 MPa, and the oxygen-enriched concentration is 21-90%; the ratio of the volume of oxygen introduced in the oxygen-enriched compressed air to the total weight of the pelletized material and the slag-making agent put into the side-blown furnace is 90-150 Nm 3 / t.

6. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: The water vapor described in step b is the water vapor produced by the waste heat boiler of the metallurgical furnace.

7. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: The gas pressure of the water vapor introduced into the side-blowing furnace is 0.1-0.5 MPa, and the temperature of the water vapor is ≥100°C.

8. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: The volume ratio of the water vapor to the oxygen-enriched compressed air is 1-40:

100.

9. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: During the reduction smelting reaction in step b, the temperature of the molten pool in the furnace is controlled to be 900-1300°C.

10. The method for reducing antimony oxide powder using a side-blown furnace according to claim 1, characterized in that: In step b, the side-blowing furnace adopts continuous feeding, and the produced crude antimony and foaming slag are discharged from the furnace regularly; among the added materials, the pelletized granules are fed into the furnace continuously, and the slag-making agent is fed continuously or intermittently at irregular intervals.

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