Apparatus and method for directly blowing granular sulfur into fuming furnace for vulcanization and volatilization

Abstract

The present application discloses an apparatus and method for directly blowing granular sulfur into a fuming furnace for vulcanization and volatilization. The apparatus comprises a sulfur storage bin (1), a conveying bin (3), a homogenizing feeder (5), a pulverized coal conveying and blowing system (9), a fuming furnace body (13), a waste heat boiler (16), a surface air cooler (17), a bag dust collector (18), a flue gas SO2 and CO monitor (19), and a slag water quenching system (20). The input amounts of granular sulfur and pulverized coal can be accurately adjusted and controlled on the basis of low-tin material conditions, avoiding the waste of sulfur and pulverized coal. The present application solves the problem, in a conventional method of adding pyrite by means of a belt for vulcanization-reduction volatilization, of waste caused by combustion of sulfur in the process or falling into a molten pool from the belt at the furnace top.

Description

A device and method for directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization Technical Field

[0001] The invention belongs to the technical field of sulfurization-reduction of low-tin material fuming furnaces, and more particularly relates to a device and method for directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization. Background Art

[0002] As the tin content of tin ore raw materials decreases year by year and their composition becomes increasingly complex, the need for improved processing technology for low-tin materials is urgent. Fuming furnaces, widely used in the volatilization and sulfidation of low-tin materials, have been around for over half a century and have accumulated a wealth of mature and operational experience. Traditionally, the industry's primary volatilization and sulfidation agent for low-tin materials has been pyrite (also known as iron pyrite), primarily due to its widespread availability and relatively low procurement price.

[0003] Pyrite is used as a volatile sulfurizing agent in a fuming furnace. It is usually put into the fuming furnace through the top belt of the fuming furnace and undergoes a sulfidation reaction with the high-temperature melt in the furnace. The sulfur in the pyrite reacts with tin oxide (SnO2, SnO). The main reactions are as follows: 2(FeS2)+O2=2(FeO)+4(S) (1) (SnO2)+2(S)=SnS(g)+SO2(g) (2) 2(FeO)+SiO2=2FeO·SiO2 (3) The overall reaction is: 2(FeS2)+O2+2(SnO2)+SiO2=2FeO·SiO2+2SnS(g)+2SO2(g) (4) 2(SnO)+3(S)=2SnS(g)+SO2(g) (5) The overall reaction is: 2(FeS2)+2O2+2(SnO)+SiO2=2FeO·SiO2+2SnS(g)+2SO2(g) (6)

[0004] Reaction (1) is the high-temperature oxidation of pyrite, releasing liquid elemental sulfur (S) and (FeO). (FeO) reacts with quartz sand SiO2 to form slag (3) to form fayalite phase 2FeO·SiO2. The volatilized gaseous SnS(g) enters the ascending flue and is oxidized by secondary air supply, resulting in the following reaction: SnS(g)+2O2=SnO2(s)+SO2(g) (7)

[0005] Tin will be collected in the surface cooler and bag filter in the solid form of tin dioxide SnO2(s) and used as raw material for subsequent smelting process recycling.

[0006] However, it can be seen from the above-mentioned overall reactions (4) and (6) that the utilization rate of sulfur in pyrite is not high. Similarly, two molecules of pyrite react with two different forms of tin oxide (SnO2, SnO) to release two molecules of sulfur dioxide gas SO2(g) respectively. In order to further improve the utilization rate of sulfur in pyrite, smelters often need to add a certain amount of pulverized coal (i.e., carbon C). The above-mentioned overall reactions (4) and (6) combined with pulverized coal (i.e., carbon C) will produce the following reactions: 2(FeS2)+O2+4(SnO2)+SiO2+4C(s)=2FeO·SiO2+4SnS(g)+4 CO2(g) (8) 2(FeS2)+2O2+4(SnO)+SiO2+3C(s)=2FeO·SiO2+4SnS(g)+3CO2(g) (9)

[0007] The added pulverized coal not only participates in the sulfidation and volatilization reactions (8) and (9) in the fuming furnace, but also partially undergoes combustion and exothermic reactions with the oxygen in the furnace, replenishing the heat required for the high-temperature melt to maintain good fluidity and related chemical reactions. That is, the carbon in the pulverized coal plays a dual role of participating in the sulfidation reaction and combustion and exothermic reaction.

[0008] Despite this, the above reaction will occur during the sulfurization and volatilization process of low-tin materials in the fuming furnace. However, the pyrite purchased by the factory usually contains at least 10% by mass of water. This water is difficult to be dehydrated and dried. Otherwise, the sulfur in the pyrite will be lost by the evaporated water, which is also very uneconomical for the smelter. After the water enters the fuming furnace with the pyrite, the following reaction will occur under high temperature conditions: (FeS2) + 2H2O = 2H2S (g) + (FeO) (10)

[0009] The hydrogen sulfide gas H2S(g) released by the above reaction will quickly escape from the molten pool into the flue gas. Except for a small amount of hydrogen sulfide gas H2S(g) that undergoes oxidation and combustion in the high-temperature zone to produce sulfur dioxide and water, most of the hydrogen sulfide gas H2S(g) does not participate in other reactions. This directly leads to a low sulfur utilization rate in the pyrite. From reaction (10), it can be calculated that 10% mass fraction of water will consume 33.3% mass fraction of pyrite, which will directly lead to unsatisfactory smelting economic indicators. In addition, the hydrogen sulfide gas H2S(g) remaining in the flue gas will also affect the subsequent flue gas acidification or desulfurization treatment. Improper treatment will cause the exhaust gas to have a strong "rotten egg" smell, polluting the atmosphere.

[0010] To this end, the present invention proposes a method for directly using sulfur as a vulcanizing agent to volatilize low-tin materials in a fuming furnace, exploring the use of sulfur as a vulcanizing agent instead of pyrite to avoid the aforementioned technical problems. Upon inquiry, it was found that currently, only in the crude tin and crude lead refining processes in China, to remove copper impurities, most domestic industries use granular sulfur added to the high-temperature crude metal. The sulfur in the sulfur reacts with the impure copper to form insoluble solid copper sulfide, which condenses during the cooling process. The condensed copper sulfide is then separated after slag removal, thereby achieving the removal of the impure copper. However, this granular sulfur is generally added to the surface of the high-temperature crude metal melt and, after stirring, is drawn into the melt to participate in the reaction. However, in the sulfidation and volatilization treatment of low-tin materials in a fuming furnace, sulfur is directly used as a vulcanizing agent and added to the molten pool. If sulfur is added to the molten pool through a furnace top belt, the sulfur will be affected by the high temperature and oxidizing atmosphere during the process of falling into the molten pool, and it is easy to burn above 248°C and directly generate sulfur dioxide. Only a small amount of granular sulfur may fall into the molten pool to participate in the vulcanization reaction, which will directly lead to a serious lack of effective utilization of the granular sulfur. There have been no reports on the research and industrial application of fuming furnace smelting or other molten pool smelting technologies and equipment that use sulfur granules as a vulcanizing agent to be directly injected into the high-temperature molten pool in related industries at home and abroad.

[0011] Summary of the Invention

[0012] The object of the present invention is to provide a device and method for directly injecting fumed and volatilized low-tin materials using granular sulfur, ensuring smooth and unblocked pipeline transportation of the sulfiding agent granular sulfur, preparing and controlling the granular sulfur feeding speed to avoid waste of direct combustion of the granular sulfur, and setting the reasonable positions of the granular sulfur and pulverized coal burners in the fuming furnace to ensure the full progress of the sulfidation-reduction combined reaction and achieve control of the optimal economic indicators of the granular sulfur and pulverized coal.

[0013] In order to achieve the above object, the present invention adopts the following technical solutions:

[0014] A device for directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization, comprising:

[0015] Sulfur storage silo, conveying silo, uniform material feeder, pulverized coal conveying and injection system, fuming furnace, waste heat boiler, surface cooler, bag dust collector, flue gas SO2 and CO monitor, slag water quenching system;

[0016] The sulfur storage bin, conveying bin, uniform material feeder, fuming furnace, waste heat boiler, surface cooler, bag dust collector and flue gas SO2 and CO monitors are connected in sequence;

[0017] The pulverized coal conveying and injection system and the slag water quenching system are respectively connected to the fuming furnace.

[0018] Preferably, the granular sulfur storage bin and the delivery bin are arranged one above the other, and a ball valve and a differential subtraction weighing device are sequentially connected between the granular sulfur storage bin and the delivery bin;

[0019] A material distribution feeder is provided at the bottom of the conveying bin, and the conveying bin is connected to the fuming furnace through the material distribution feeder;

[0020] A vulcanization compressed air valve connected to the bottom side of the delivery bin is also provided.

[0021] Preferably, the fuming furnace comprises a fuming furnace body, a sulfur injection burner, a pulverized coal injection burner, a slag outlet, a temperature monitor, an observation hole and a furnace top feed port;

[0022] The sulfur injection burner and the pulverized coal injection burner are respectively arranged on both sides of the bottom of the fuming furnace body; the pulverized coal injection burner is arranged at a height of 100 mm from the bottom of the fuming furnace body, and the sulfur injection burner is arranged at a height of 100 to 150 mm above and parallel to the upper part of the pulverized coal injection burner; the pulverized coal injection burner is connected to the pulverized coal conveying and ejection system; the sulfur injection burner is connected to the uniform material feeder;

[0023] The slag tapping port is arranged at one side of the bottom of the fuming furnace body, and the slag tapping port is connected to the slag water quenching system;

[0024] The temperature monitor and the observation hole are respectively arranged on the side wall of the upper middle portion of the fumigation furnace body;

[0025] The furnace top feed port is arranged on one side of the top of the fuming furnace body; a furnace top belt feeding system matching the furnace top feed port is arranged above the furnace top feed port;

[0026] The fumigation furnace body is connected to the waste heat boiler.

[0027] Preferably, the above-mentioned device for directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization further comprises: a sulfur feeding valve, a nitrogen delivery pipeline valve, a coal delivery air valve, and a secondary air valve;

[0028] One side of the sulfur feeding valve is connected to the uniform material feeder, and the other side is connected to the nitrogen delivery pipeline valve, and the other side of the nitrogen delivery pipeline valve is connected to the sulfur injection burner;

[0029] One side of the coal feeding air valve is connected to the pulverized coal feeding and injection system, and the other side is connected to the pulverized coal injection burner;

[0030] The secondary air valve is arranged on the side wall of the bottom of the waste heat boiler;

[0031] In the present invention, both the nitrogen delivery pipeline valve and the nitrogen delivery pipeline valve are provided with pressure gauges matching therewith.

[0032] Another object of the present invention is to provide a method for directly injecting granular sulfur into a fuming furnace for volatilization, which comprises the following steps:

[0033] (1) After sieving the purchased sulfur, send it to the sulfur storage bin, then open the lower ball valve and put the sulfur into the delivery bin; keep the nitrogen delivery pipeline valve open, the delivery air pressure at 3-6 Bar, and keep the sulfur feeding valve closed;

[0034] (2) After the tin ore in the fuming furnace is completely melted, close the ball valve, open the sulfurized compressed air valve to pressurize the conveying bin, and after the pressure in the conveying bin reaches 3-4 Bar, open the sulfur feeding valve and start the uniform feeder to feed the fuming furnace. When the weight of the sulfur feed reaches 90% of the calculated amount, take a sample of the molten slag in the fuming furnace and send it for analysis. After the tin content in the slag is ≤0.2%, discharge the slag to the slag water quenching system; if the tin content in the slag is higher than 0.2%, take a sample of the molten slag every 1 minute and then send it for analysis. After the tin content in the slag is ≤0.2%, stop the sulfur feeding injection and immediately open the slag port of the fuming furnace to carry out the slag water quenching operation;

[0035] (3) Step (2) Open the sulfur feeding valve, start the uniform feeder to feed the fuming furnace, and control the pulverized coal injection system to uniformly feed the pulverized coal into the fuming furnace. At the same time, observe the flue gas monitoring situation at the bag filter outlet to ensure that the SO2 and CO concentrations of the flue gas during the sulfur injection and pulverized coal feeding processes are respectively 0.9-1.5% and 7000-10000 ppm. If the concentrations are lower or higher than the range, increase or decrease the sulfur and pulverized coal feeding amounts respectively, and fine-tune them within ±0.2 t / h, or adjust the opening of the secondary air valve to control the CO concentration within the above range.

[0036] (4) Check the situation inside the fuming furnace through the observation hole. After confirming that the slag in the furnace is completely discharged, close the nitrogen delivery pipeline valve and the coal delivery air valve, disassemble the sulfur injection burner and pulverized coal injection burner for blockage inspection and cleaning, and reinstall them to their original positions. Keep the sulfur delivery air and pulverized coal delivery air in the open state again, and keep their delivery air pressure stable at 3 to 6 Bar. Then start the fuming furnace production operation and enter the next cycle.

[0037] Preferably, in step (1), the sulfur content of the purchased sulfur is ≥99%, the purchased sulfur is first passed through a 3-mesh sieve, and after the first screening, the granular sulfur under the sieve is passed through a 7-mesh sieve again, the sulfur remaining after the first screening is used for other purposes, and after the 7-mesh sieve, that is, after the second screening, the sulfur under the sieve is used for other purposes, while the sulfur on the sieve is retained, so as to ensure that the particle size of the granular sulfur after the second screening is between 2.8 and 6.0 mm;

[0038] The gas used by the vulcanization compressed air valve to pressurize the conveying bin in step (2) is pure nitrogen, and the water content of the pure nitrogen is ≤0.5%.

[0039] Preferably, the parameters of the uniform feeder in step (2) are: within 10 minutes of the feed head, starting from 0 t / h, increasing by 0.1 t / h every 1 minute, that is, after 10 minutes of starting, the feeding speed of the uniform feeder 5 will reach 1.0 t / h, and the feeding speed is kept within 1.0 ± 0.2 t / h for fine adjustment;

[0040] The weight of the sulfur feed is calculated by the following method: the total weight of the sulfur feed is calculated based on 30% wt of the tin metal content of the tin ore in the fuming furnace, and the excess coefficient is controlled at 5% to 10%.

[0041] Preferably, the parameters of the pulverized coal injection system in step (3) are that the pulverized coal feeding rate is 1.3 to 1.8 t / h and the conveying air pressure is stable at 3 to 6 Bar;

[0042] The particle size control requirements of the pulverized coal are: passing through a 400 mesh sieve, fixed carbon content ≥65% wt, moisture content ≤2.5% wt, ash content ≤15% wt, and volatile matter ≤15% wt, wherein passing through a 400 mesh sieve means that more than 90 wt% of the pulverized coal in the total pulverized coal can pass through the 400 mesh sieve.

[0043] Preferably, step (2) further comprises: after the tin content of the melt slag is ≤0.2%, stopping the uniform feeder, closing the sulfur feed valve after 5 minutes, continuing to keep the nitrogen delivery pipeline valve in the normally open state, keeping the pulverized coal feed into the fuming furnace, adjusting the pulverized coal feed rate to 0.5-1.0 t / h, and observing the temperature monitor at the same time to ensure that the rising flue temperature of the fuming furnace is between 1100 and 1150°C. If it is lower or higher than this temperature range, the coal feed rate is increased or decreased by 0.1-0.3 t / h respectively, until the slag in the fuming furnace is completely discharged, stopping the pulverized coal feed, keeping the coal feed air valve in the normally open state, and ensuring that the coal injection burner is not blocked.

[0044] Preferably, in addition to using pulverized coal as the heat source supply and sulfide-reduction effect of the fuming furnace, pipeline natural gas, liquefied natural gas or liquefied petroleum gas with the same calorific value can also be used instead of pulverized coal, but the pressure of the gas at the burner end of the fuming furnace is required to be maintained above 4 Bar; in addition, lump coal can also be mixed with the gas for use, but the lump coal needs to be transported into the fuming furnace through the furnace top feeding belt, and the lump coal is only used for sulfide-reduction.

[0045] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0046] ① The sulfur that meets the particle size standards after screening can ensure smooth pipeline transportation, avoiding blockage caused by large sulfur particles or fine sulfur powder adhering to the inner wall of the pipeline;

[0047] ② Using pure nitrogen filtered through a dryer to transport granular sulfur can prevent moisture in the transporting gas medium, which may cause sulfur to stick to the inner wall of the pipeline. It can also act as an inert gas to protect the granular sulfur, avoiding the safety risk of sulfur burning before being injected into the fuming furnace.

[0048] ③ Granular sulfur is directly injected into the molten pool of the fuming furnace to complete the sulfurization-reduction process, significantly improving the direct utilization rate of sulfur. This avoids the waste of direct combustion caused by the existing high-difference material drop process of adding it to the molten pool through the furnace top belt, as well as the problem of air pollution caused by the "rotten egg" smell of the tail exhaust.

[0049] ④ Using granular sulfur instead of traditional pyrite as the sulfiding agent of the fuming furnace to fume and volatilize low-tin materials can avoid the amount of iron brought into the fuming furnace by the use of pyrite, which not only affects the pH value of the slag, but also requires the addition of quartz sand SiO2 to adjust the pH value of the slag (see reaction 3). It will also affect the effective hearth capacity of the fuming furnace, resulting in insufficient processing capacity of the fuming furnace per unit time.

[0050] ⑤ Reasonable placement of the granular sulfurization injection burner and pulverized coal injection burner in the fuming furnace can ensure the full progress of the sulfurization-reduction combined reaction and achieve the optimal economic index control of granular sulfur and pulverized coal;

[0051] ⑥ In addition to using pulverized coal as a reducing agent and for heating, the present invention can also use pipeline natural gas, liquefied natural gas or liquefied petroleum gas and other fuel gases with the same calorific value as an alternative, which can achieve the purpose of the same fuming furnace sulfurization-reduction treatment method for low-tin materials and realize the green use of clean energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0053] FIG1 is a schematic diagram of the device of the present invention

[0054] The numbered components in the figure are: 1. Granular sulfur storage bin, 2. Ball valve, 3. Conveying bin, 4. Sulfurization compressed air valve, 5. Uniform material feeder, 6. Sulfur feeding valve, 7. Differential subtraction weigher, 8. Nitrogen conveying pipeline valve, 9. Pulverized coal conveying system, 10. Coal feeding and conveying air valve, 11. Pulverized coal injection burner, 12. Sulfur injection burner, 13. Fuming furnace body, 14. Temperature monitor, 15. Secondary air valve, 16. Waste heat boiler, 17. Surface cooler, 18. Bag dust collector, 19. Flue gas SO2 and CO monitor, 20. Slag water quenching system, 21. Furnace top belt feeding system, 22. Furnace top feed port, 23. Slag discharge port, 24. Observation hole, 25. Dust discharger. DETAILED DESCRIPTION

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0056] Example 1

[0057] Referring to FIG1 , this embodiment provides a device for directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization, comprising:

[0058] Sulfur storage bin 1, conveying bin 3, uniform material feeder 5, pulverized coal conveying and injection system 9, fuming furnace, waste heat boiler 16, surface cooler 17, bag filter 18, flue gas SO2 and CO monitor 19, slag water quenching system 20;

[0059] Among them, the sulfur storage bin 1, the conveying bin 2, the uniform material feeder 5, the fuming furnace, the waste heat boiler 16, the surface cooler 17, the bag dust collector 18 and the flue gas SO2 and CO monitor 19 are connected in sequence;

[0060] The pulverized coal conveying and injection system 9 and the slag water quenching system 20 are respectively connected to the fuming furnace.

[0061] Among them, the granular sulfur storage bin 1 and the conveying bin 3 are arranged up and down, and the granular sulfur storage bin 1 and the conveying bin 3 are connected in sequence with a ball valve 2 and a differential subtraction weighing device 7;

[0062] A material distribution feeder 5 is provided at the bottom of the conveying bin 3, and the conveying bin 3 is connected to the fuming furnace through the material distribution feeder 5;

[0063] A vulcanization compressed air valve 4 connected to the bottom side of the delivery bin 3 is also provided.

[0064] In order to further optimize the above technical solution, the fuming furnace includes a fuming furnace body 13, a sulfur injection burner 12, a pulverized coal injection burner 11, a slag outlet 23, a temperature monitor 14, an observation hole 24 and a furnace top feed port 22;

[0065] The sulfur injection burner 12 and the pulverized coal injection burner 11 are respectively arranged on both sides of the bottom of the fuming furnace body 13; the pulverized coal injection burner 11 is arranged at a height of 100 mm from the bottom of the fuming furnace body 13, and the sulfur injection burner 12 is arranged at a height of 100 to 150 mm above and parallel to the upper part of the pulverized coal injection burner 11; the pulverized coal injection burner 11 is connected to the pulverized coal conveying and ejecting system 9; the sulfur injection burner 12 is connected to the uniform material feeder 5;

[0066] The slag tapping port 23 is provided at one side of the bottom of the fuming furnace body 13 and is connected to the slag water quenching system 20;

[0067] The temperature monitor 14 and the observation hole 24 are respectively arranged on the side wall of the upper middle portion of the fumigation furnace body 13;

[0068] A furnace top feed port 22 is provided on one side of the top of the fuming furnace body 13; a furnace top belt feeding system 21 matching the furnace top feed port 22 is provided above the furnace top feed port 22;

[0069] The fuming furnace body 13 is connected to the waste heat boiler 16 .

[0070] In order to further optimize the above technical solution, the above-mentioned device for directly injecting granular sulfur into the fuming furnace for sulfurization and volatilization further includes: a sulfur feeding valve 6, a nitrogen delivery pipeline valve 8, a coal feeding air valve 10 and a secondary air valve 15;

[0071] One side of the sulfur feeding valve 6 is connected to the uniform feeder 5, and the other side is connected to the nitrogen delivery pipeline valve 8, and the other side of the nitrogen delivery pipeline valve 8 is connected to the sulfur injection burner 12;

[0072] One side of the coal feeding air valve 10 is connected to the pulverized coal feeding and injection system 9, and the other side is connected to the pulverized coal injection burner 11;

[0073] The secondary air damper 15 is provided on the side wall of the bottom of the waste heat boiler 16 .

[0074] In order to further optimize the above technical solution, the above-mentioned device for directly injecting granular sulfur into the fuming furnace for sulfurization and volatilization also includes: a dust discharger 25; the dust discharger 25 is arranged at the bottom between the waste heat boiler 16 and the surface cooler 17, and is connected to the waste heat boiler 16, the surface cooler 17 and the bag dust collector 18.

[0075] Example 2

[0076] 4m 2Taking the fuming furnace as the object, a single furnace processes 25 tons of low-tin materials with a tin grade of 5%wt in 6 hours. According to theoretical calculation, the sulfur content of the required vulcanizing agent is 25 tons × 5%wt × 30% = 0.375 tons. Taking the excess coefficient as 5%, the total sulfur content is 0.375 × (1 + 5%) = 0.394 tons.

[0077] To this end, the purchased granular sulfur is first passed through a 3-mesh sieve. After the first screening, the granular sulfur under the sieve is passed through a 7-mesh sieve again. The sulfur remaining after the first screening is used for other purposes. After the 7-mesh sieve, that is, after the second screening, the sulfur under the sieve is used for other purposes, while the sulfur on the sieve is retained, that is, the particle size of the granular sulfur after the two screenings is ensured to be between 2.8 and 6.0 mm, and the weight of the granular sulfur is 0.394 tons. The granular sulfur is delivered to a dedicated sulfur storage bin 1, and after opening the lower ball valve 2, the granular sulfur is placed into the conveying bin 3; the nitrogen conveying pipeline valve 8 is kept open, the conveying air pressure is kept at 3 Bar, and the sulfur feeding valve 6 is kept closed;

[0078] After the tin ore in the fuming furnace is completely melted, that is, when the melt temperature is 1150℃, close the ball valve 2, open the sulfurization compressed air valve 4 to pressurize the conveying bin 3, and when the pressure in the conveying bin 3 reaches 3Bar, open the sulfur feeding valve 6, and start the uniform feeder 5 at the same time. The feeding speed of the uniform feeder 5 is 10min, starting from 0t / h, and increasing by 0.1t / h every 1min, that is, starting for 10min Afterwards, the feeding speed of the uniform feeder 5 will reach 1.0 t / h, and this feeding speed will be fine-tuned within 1.0±0.2 t / h. When the sulfur feed amount (weight) reaches 90% of the calculated amount, that is, the granular sulfur conveying bin differential subtraction weighing device 7 shows that approximately 0.36 tons of sulfur has been conveyed, the molten slag sample in the fuming furnace body 13 is taken through the sampling rod and sent for laboratory analysis. When the slag contains tin ≤ 0.2%, it can be sent to the slag water quenching system 20 for slag tapping and water quenching. If the slag contains tin higher than 0.2%, a molten slag sample is taken every 1 minute and sent for laboratory analysis. When the slag contains tin ≤ 0.2%, the sulfur feed injection can be stopped, and the slag opening 23 can be immediately opened for slag tapping and water quenching.

[0079] While the sulfur is continuously injected into the fuming furnace through the conveying air duct, the pulverized coal conveying and injection system 9 is controlled to uniformly feed the pulverized coal into the fuming furnace body 13, and the pulverized coal feeding speed is maintained at 1.3 t / h. The conveying air pressure is stable at 3 Bar to ensure a sulfiding-reducing atmosphere in the fuming furnace. At the same time, the SO2 and CO monitors 19 of the flue gas at the outlet of the bag filter 18 are monitored to ensure that the SO2 and CO concentrations of the flue gas during the sulfur injection and pulverized coal feeding processes are respectively 0.9-1.5% and 7000-10000 ppm. If the concentrations are lower or higher than the range, the sulfur and pulverized coal feeding rates should be increased or decreased respectively, and both should be fine-tuned within ±0.2 t / h. The CO concentration can also be controlled within the above range by adjusting the opening of the secondary air valve 15 of the rising flue of the fuming furnace;

[0080] When the tin content of the molten slag in the fuming furnace body 13 is ≤0.2%, stop the sulfur feeding injection, that is, first stop the uniform feeder 5, and close the sulfur feeding valve 6 after 5 minutes. Continue to keep the nitrogen delivery pipeline valve 8 in the normally open state, and still keep the pulverized coal feeding into the fuming furnace, but the pulverized coal feeding speed needs to be adjusted to 0.5t / h. At the same time, observe the temperature monitoring monitor 14 of the rising flue of the fuming furnace to ensure that the temperature of the rising flue of the fuming furnace is between 1100 and 1150°C. If it is lower or higher than this temperature range, increase or decrease the coal feeding speed by 0.1 to 0.3t / h respectively. After the slag in the fuming furnace body 13 is completely discharged, the coal feeding can be stopped, but the coal feeding air valve 10 needs to be kept in the normally open state to ensure that the coal injection burner 11 is not blocked.

[0081] Observe the situation inside the fuming furnace body 13 through the observation hole 24. After confirming that the slag in the furnace is completely discharged, close the nitrogen delivery pipeline valve 8 and the coal delivery air valve 10. Disassemble the sulfur injection burner 12 and the pulverized coal injection burner 11 for blockage inspection and cleaning. Then reinstall the burners to their original positions. Keep the sulfur delivery air and the pulverized coal delivery air in the open state again, and keep their delivery air pressures stable at 3 Bar. Then start the fuming furnace production operation and enter the next cycle.

[0082] The sulfur injection burner 12 and the pulverized coal injection burner 11 are respectively arranged on both sides of the fuming furnace body 13, wherein the pulverized coal injection burner 11 is arranged at a height of 100 mm from the bottom of the fuming furnace body 13, and the sulfur injection burner 12 is arranged at a height of 100 mm parallel to the upper part of the pulverized coal injection burner 11.

[0083] Example 3

[0084] 8m 2Taking the fuming furnace as the object, a single furnace can process 50 tons of low-tin materials with a tin grade of 5%wt in 6 hours. According to theoretical calculation, the sulfur content of the required vulcanizing agent is 50 tons × 5%wt × 30% = 0.75 tons. Taking the excess coefficient as 10%, the total sulfur content is 0.75 × (1 + 10%) = 0.825 tons.

[0085] To this end, the purchased granular sulfur is first passed through a 3-mesh sieve. After the first screening, the granular sulfur under the sieve is passed through a 7-mesh sieve again. The sulfur remaining after the first screening is used for other purposes. After the 7-mesh sieve, that is, after the second screening, the sulfur under the sieve is used for other purposes, while the sulfur on the sieve is retained, that is, the particle size of the granular sulfur after the two screenings is ensured to be between 2.8 and 6.0 mm, and the weight of the granular sulfur is 0.825 tons. The granular sulfur is delivered to a dedicated sulfur storage bin 1, and after opening the lower ball valve 2, the granular sulfur is placed into the conveying bin 3; the conveying air valve 8 at the bottom of the sulfur injection is kept open, the conveying air pressure is kept at 5 Bar, and the sulfur feeding valve 6 is kept closed;

[0086] After the tin ore in the fuming furnace is completely melted, that is, when the melt temperature is 1200℃, close the ball valve 2, open the sulfurized compressed air valve 4 to pressurize the conveying bin 3, and when the pressure in the conveying bin 3 reaches 3Bar, open the sulfur feeding valve 6, and start the uniform feeder 5 at the same time. The feeding speed of the uniform feeder 5 is 10min. Start at 0t / h and increase by 0.1t / h every 1min. That is, after 10min of starting, the feeding speed of the uniform feeder 5 will reach 1.0t / h, and maintain the feeding speed at 1.0±0.2t / h. Fine adjustments are made within h. When the sulfur feed amount (weight) reaches 90% of the calculated amount, that is, the granular sulfur delivery bin differential subtraction weighing device 7 shows that approximately 0.74 tons of sulfur has been delivered, a sample of the molten slag in the fuming furnace body 13 is taken through a sampling rod and sent for laboratory analysis. When the slag contains tin ≤ 0.2%, it can be sent to the slag water quenching system 20 for slag tapping and water quenching. If the slag contains tin higher than 0.2%, a sample of the molten slag is taken every 1 minute and sent for laboratory analysis. When the slag contains tin ≤ 0.2%, the sulfur feed injection is stopped and the slag opening 23 is immediately opened for slag tapping and water quenching.

[0087] While the sulfur is continuously injected into the fuming furnace through the conveying air duct, the pulverized coal conveying and injection system 9 is controlled to uniformly feed the pulverized coal into the fuming furnace body 13, and the pulverized coal feeding speed is maintained at 1.5 t / h. The conveying air pressure is stabilized at 5 Bar to ensure a sulfiding-reducing atmosphere in the fuming furnace. At the same time, the SO2 and CO monitors 19 of the flue gas at the outlet of the bag filter 18 are monitored to ensure that the SO2 and CO concentrations of the flue gas during the sulfur injection and pulverized coal feeding processes are respectively 0.9-1.5% and 7000-10000 ppm. If the concentrations are lower or higher than the range, the sulfur and pulverized coal feeding rates should be increased or decreased respectively, and both should be fine-tuned within ±0.2 t / h. The CO concentration can also be controlled within the above range by adjusting the opening of the secondary air valve 15 of the rising flue of the fuming furnace;

[0088] When the tin content of the molten slag in the fuming furnace body 13 is ≤0.2%, stop the sulfur feeding injection, that is, first stop the uniform feeder 5, and close the sulfur feeding valve 6 after 5 minutes. Continue to keep the nitrogen delivery pipeline valve 8 in the normally open state, and still keep the pulverized coal feeding into the fuming furnace, but the pulverized coal feeding speed needs to be adjusted to 0.5t / h. At the same time, observe the temperature monitoring monitor 14 of the rising flue of the fuming furnace to ensure that the temperature of the rising flue of the fuming furnace is between 1100 and 1150°C. If it is lower or higher than this temperature range, increase or decrease the coal feeding speed by 0.1 to 0.3t / h respectively. After the slag in the fuming furnace body 13 is completely discharged, the coal feeding can be stopped, but the coal feeding air valve 10 needs to be kept in the normally open state to ensure that the coal injection burner 11 is not blocked.

[0089] Observe the situation inside the fuming furnace body 13 through the observation hole 24. After confirming that the slag in the furnace is completely discharged, close the nitrogen delivery pipeline valve 8 and the coal delivery air valve 10. Disassemble the sulfur injection burner 12 and the pulverized coal injection burner 11 for blockage inspection and cleaning. Then reinstall the burners to their original positions. Keep the sulfur delivery air and the pulverized coal delivery air in the open state again, and keep their delivery air pressures stable at 5 Bar. Then start the fuming furnace production operation and enter the next cycle.

[0090] The sulfur injection burner 12 and the pulverized coal injection burner 11 are respectively arranged on both sides of the fuming furnace body 13, wherein the pulverized coal injection burner 11 is arranged at a height of 100 mm from the bottom of the fuming furnace body 13, and the sulfur injection burner 12 is arranged at a height of 100 mm parallel to the upper part of the pulverized coal injection burner 11.

[0091] Example 4

[0092] 16m 2Taking the fuming furnace as an example, a single furnace can process 100 tons of low-tin material with a tin grade of 11%wt within 6 hours. According to theoretical calculation, the sulfur content of the required vulcanizing agent is 100 tons × 11%wt × 30% = 3.3 tons. Taking the excess coefficient as 10%, the total sulfur content is 3.3 × (1 + 10%) = 3.63 tons.

[0093] To this end, the purchased granular sulfur is first passed through a 3-mesh sieve. After the first screening, the granular sulfur under the sieve is passed through a 7-mesh sieve again. The sulfur remaining after the first screening is used for other purposes. After the 7-mesh sieve, that is, after the second screening, the sulfur under the sieve is used for other purposes, while the sulfur on the sieve is retained, that is, the particle size of the granular sulfur after the two screenings is ensured to be between 2.8 and 6.0 mm. The weight of the granular sulfur is 3.63 tons. The granular sulfur is delivered to a dedicated sulfur storage bin 1, and after opening the lower ball valve 2, the granular sulfur is placed into the conveying bin 3; the nitrogen conveying pipeline valve 8 is kept open, the conveying air pressure is kept at 6 Bar, and the sulfur feeding valve 6 is kept closed;

[0094] After the tin ore in the fuming furnace is completely melted, that is, when the melt temperature is 1250℃, close the ball valve 2, open the sulfurized compressed air valve 4 to pressurize the conveying bin 3, and when the pressure in the conveying bin 3 reaches 4Bar, open the sulfur feeding valve 6, and start the uniform feeder 5 at the same time. The feeding speed of the uniform feeder 5 is 10min. Start at 0t / h and increase by 0.1t / h every 1min. That is, after 10min of starting, the feeding speed of the uniform feeder 5 will reach 1.0t / h, and maintain the feeding speed at 1.0±0.2t The flow rate is fine-tuned within 1 minute. When the sulfur feed amount (weight) reaches 90% of the calculated amount, i.e., the granular sulfur delivery bin differential subtraction weighing device 7 indicates that approximately 3.3 tons of sulfur has been delivered, a sample of the molten slag in the fuming furnace body 13 is taken through a sampling rod and sent for laboratory analysis. When the slag contains tin ≤ 0.2%, the slag can be sent to the slag quenching system 20 for slag tapping and quenching. If the slag contains tin higher than 0.2%, a sample of the molten slag is taken every minute and sent for laboratory analysis. When the slag contains tin ≤ 0.2%, the sulfur feed injection is stopped and the slag opening 23 is immediately opened for slag tapping and quenching.

[0095] While the sulfur is continuously injected into the fuming furnace through the conveying air duct, the pulverized coal conveying and injection system 9 is controlled to uniformly feed the pulverized coal into the fuming furnace body 13, and the pulverized coal feeding speed is maintained at 1.8 t / h. The conveying air pressure is stable at 6 Bar to ensure a sulfiding-reducing atmosphere in the fuming furnace. At the same time, the SO2 and CO monitors 19 of the flue gas at the outlet of the bag filter 18 are monitored to ensure that the SO2 and CO concentrations of the flue gas during the sulfur injection and pulverized coal feeding processes are respectively 0.9-1.5% and 7000-10000 ppm. If the concentrations are lower or higher than the range, the sulfur and pulverized coal feeding rates should be increased or decreased respectively, and both should be fine-tuned within ±0.2 t / h. The CO concentration can also be controlled within the above range by adjusting the opening of the secondary air valve 15 of the rising flue of the fuming furnace;

[0096] When the tin content of the molten slag in the fuming furnace body 13 is ≤0.2%, stop the sulfur feeding injection, that is, first stop the uniform feeder 5, and close the sulfur feeding valve 6 after 5 minutes. Continue to keep the nitrogen delivery pipeline valve 8 in the normally open state, and still keep the pulverized coal feeding into the fuming furnace, but the pulverized coal feeding speed needs to be adjusted to 1.0 t / h. At the same time, observe the temperature monitoring monitor 14 of the rising flue of the fuming furnace to ensure that the temperature of the rising flue of the fuming furnace is between 1100 and 1150°C. If it is lower or higher than this temperature range, increase or decrease the coal feeding speed by 0.1 to 0.3 t / h respectively. After the slag in the fuming furnace body 13 is completely discharged, the coal feeding can be stopped, but the coal feeding air valve 10 needs to be kept in the normally open state to ensure that the coal injection burner 11 is not blocked.

[0097] Observe the situation inside the fuming furnace body 13 through the observation hole 24. After confirming that the slag in the furnace is completely discharged, close the nitrogen delivery pipeline valve 8 and the coal delivery air valve 10. Disassemble the sulfur injection burner 12 and the pulverized coal injection burner 11 for blockage inspection and cleaning. Then reinstall the burners to their original positions. Keep the sulfur delivery air and the pulverized coal delivery air in the open state again, and keep their delivery air pressures stable at 6 Bar. Then start the fuming furnace production operation and enter the next cycle.

[0098] The sulfur injection burner 12 and the pulverized coal injection burner 11 are respectively arranged on both sides of the fuming furnace body 13, wherein the pulverized coal injection burner 11 is arranged at a height of 100 mm from the bottom of the fuming furnace body 13, and the sulfur injection burner 12 is arranged at a height of 150 mm parallel to the upper part of the pulverized coal injection burner 11.

[0099] Comparative Example 1

[0100] 4m 2Taking the fuming furnace as the object, other conditions and factors remain unchanged. Only taking pyrite with a sulfur content of about 35% as an example, it also contains 50% iron, 10% water content, and takes the excess coefficient as 5%, that is, the total sulfur content is 0.394 tons, then the amount of pyrite required is 0.394 ÷ 35% = 1.13 tons;

[0101] The pyrite was transported into the fuming furnace bath via the furnace top belt to participate in the sulfidation-reduction reaction. After the 1.13 tons of pyrite were completely put into the furnace, the fuming furnace was kept fuming and volatilizing for 10 minutes. Samples were taken for analysis and the tin content of the slag was 0.5%wt, indicating poor fuming effect. An additional 0.07 tons of pyrite was required to continue fuming and volatilizing in the fuming furnace to ensure that the tin content of the slag was below 0.2%. The slag was discharged through the slag outlet for water quenching. After the quenching, the water vapor had a "rotten egg" smell. It was obvious that the amount of pyrite used exceeded the theoretical value, the reaction was insufficient, and there was a lot of waste. In addition, the sulfidation-reduction process also required the addition of about 0.3 tons of 96% grade quartz sand according to the slag formation reaction (3), which increased the operating load and cost of the fuming furnace.

[0102] Comparative Example 2

[0103] 8m 2 Taking the fuming furnace as the object, other conditions and factors remain unchanged. Only taking the pyrite with a sulfur content of about 35% as an example, it also contains 50% iron and 10% moisture. Taking the excess coefficient as 10%, that is, the total sulfur content is 0.825 tons, then the amount of pyrite required is 0.825 ÷ 35% = 2.36 tons;

[0104] The pyrite was transported into the fuming furnace molten pool via the furnace top belt to participate in the sulfidation-reduction reaction. After the 2.36 tons of pyrite were completely put into the furnace, the fuming furnace was kept fuming and volatilizing for 10 minutes. Samples were taken for analysis and the tin content of the slag reached 0.48%wt, indicating poor fuming effect. An additional 0.15 tons of pyrite was required to continue to be put into the fuming furnace for fuming and volatilization to ensure that the tin content of the slag was less than 0.2%. The slag was discharged through the slag outlet for water quenching. After the quenching, the water vapor could smell "rotten eggs". It is obvious that the amount of pyrite used exceeded the theoretical value, the reaction was not sufficient, and there was a lot of waste. In addition, the sulfidation-reduction process also required the addition of about 0.6 tons of 96% grade quartz sand according to the slag formation reaction (3), which increased the operating load and cost of the fuming furnace.

[0105] Comparative Example 3

[0106] 16m 2 Taking the fuming furnace as the object, other conditions and factors remain unchanged. Only taking the pyrite with a sulfur content of about 35% as an example, it also contains 50% iron and 10% moisture. Taking the excess coefficient as 10%, that is, the total sulfur content is 3.63 tons, then the amount of pyrite required is 3.63 ÷ 35% = 10.4 tons;

[0107] The pyrite was transported into the fuming furnace molten pool via the furnace top belt to participate in the sulfidation-reduction reaction. After the 10.4 tons of pyrite were completely put into the furnace, the fuming furnace was kept fuming and volatilizing for 10 minutes. Samples were taken for analysis and the tin content of the slag was 0.7%wt, indicating poor fuming effect. An additional 0.47 tons of pyrite was required to continue fuming and volatilizing in the fuming furnace to ensure that the tin content of the slag was less than 0.2%. The slag was discharged through the slag outlet for water quenching. After the quenching, the water vapor could smell "rotten eggs". It was obvious that the amount of pyrite used exceeded the theoretical value, the reaction was not sufficient, and there was a lot of waste. In addition, the sulfidation-reduction process also required the addition of about 2.89 tons of 96% grade quartz sand according to the slag formation reaction (3), which increased the operating load and cost of the fuming furnace.

[0108] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0109] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for directly injecting granular sulfur into a fuming furnace for vulcanization, characterized in that: include: Sulfur storage bin, conveying bin, uniform material feeder, pulverized coal conveying and injection system, fuming furnace, waste heat boiler, surface cooler, bag filter, flue gas SO2 and CO monitor, slag water quenching system; The sulfur storage bin, conveying bin, uniform material feeder, fuming furnace, waste heat boiler, surface cooler, bag filter and flue gas SO2 and CO monitors are connected in sequence; The pulverized coal conveying and injection system and the slag water quenching system are respectively connected to the fuming furnace.

2. The device for directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization according to claim 1 is characterized in that: The granular sulfur storage bin and the conveying bin are arranged vertically, and a spherical valve and a differential subtraction weighing device are connected between the granular sulfur storage bin and the conveying bin in sequence; A material-distributing feeder is provided at the bottom of the conveying bin, and the conveying bin is connected to the fuming furnace through the material-distributing feeder; A vulcanization compressed air valve connected to the bottom side of the delivery bin is also provided.

3. The device for directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization according to claim 2, characterized in that: The fuming furnace comprises a fuming furnace body, a sulfur injection burner, a pulverized coal injection burner, a slag discharge port, a temperature monitor, an observation hole and a furnace top feed port; The sulfur injection burner and the pulverized coal injection burner are respectively arranged on both sides of the bottom of the fuming furnace body; the pulverized coal injection burner is arranged at a height of 100 mm from the bottom of the fuming furnace body, and the sulfur injection burner is arranged at a height of 100 to 150 mm above the pulverized coal injection burner; the pulverized coal injection burner is connected to the pulverized coal conveying and ejecting system; the sulfur injection burner is connected to the uniform material feeder; The slag discharge port is arranged at one side of the bottom of the fuming furnace body, and the slag discharge port is connected to the slag water quenching system; The temperature monitor and the observation hole are respectively arranged on the side wall of the upper middle part of the fumigation furnace body; The furnace top feed inlet is arranged on one side of the top of the fuming furnace body; a furnace top belt feeding system matching the furnace top feed inlet is arranged above the furnace top feed inlet; The fume furnace body is connected to the waste heat boiler.

4. The device for directly injecting granular sulfur into a fuming furnace for volatilization according to claim 3 is characterized in that: Also includes: Sulfur feed valves, nitrogen delivery pipeline valves, coal delivery air valves and secondary air valves; One side of the sulfur feeding valve is connected to the uniform material feeder, and the other side is connected to the nitrogen delivery pipeline valve, and the other side of the nitrogen delivery pipeline valve is connected to the sulfur injection burner; One side of the coal feeding and conveying air valve is connected to the pulverized coal conveying and injection system, and the other side is connected to the pulverized coal injection burner; The secondary air valve is arranged on the side wall of the bottom of the waste heat boiler.

5. A method for directly injecting granular sulfur into a fuming furnace for vulcanization, characterized in that: The device according to claim 4 specifically comprises the following steps: (1) After sieving the purchased sulfur, send it to the sulfur storage bin, then open the lower ball valve and put the sulfur into the delivery bin; keep the nitrogen delivery pipeline valve open, the delivery air pressure at 3-6 Bar, and keep the sulfur feeding valve closed; (2) After the tin ore in the fuming furnace is completely melted, close the ball valve, open the sulfurized compressed air valve to pressurize the conveying bin, and after the pressure in the conveying bin reaches 3-4 Bar, open the sulfur feeding valve, start the uniform feeder to feed the fuming furnace, and when the weight of the sulfur feed reaches 90% of the calculated amount, take a sample of the molten slag in the fuming furnace and send it for analysis. After the tin content of the slag is ≤0.2%, discharge the slag to the slag water quenching system; if the tin content of the slag is higher than 0.2%, take a sample of the molten slag every 1 minute, and then send it for analysis. After the tin content of the slag is ≤0.2%, stop the sulfur feeding injection, and immediately open the slag port of the fuming furnace to discharge the slag for water quenching; (3) Step (2) Open the sulfur feeding valve, start the uniform feeder to feed the fuming furnace, and control the pulverized coal injection system to uniformly feed the pulverized coal into the fuming furnace. At the same time, observe the flue gas monitoring at the bag filter outlet to ensure that the SO2 and CO concentrations of the flue gas during the sulfur injection and pulverized coal feeding process are If the CO concentration is lower or higher than the above range, the sulfur and pulverized coal feed rates are increased or decreased respectively, and the adjustment is made within ±0.2t / h, or the secondary air valve opening is adjusted to control the CO concentration within the above range. (4) Check the situation inside the fuming furnace through the observation hole. After confirming that the slag in the furnace is completely discharged, close the nitrogen delivery pipeline valve and the coal delivery air valve, disassemble the sulfur injection burner and pulverized coal injection burner for blockage inspection and cleaning, and reinstall them back to their original positions. Keep the sulfur delivery air and pulverized coal delivery air in the open state again, and keep their delivery air pressures stable at 3 to 6 Bar. Then start the fuming furnace production operation and enter the next cycle.

6. The method of directly injecting granular sulfur into a fuming furnace for vulcanization according to claim 5, characterized in that: In step (1), the sulfur content of the purchased sulfur is ≥ 99%, and the screening is to screen the purchased particles to a particle size of 2.8 to 6.0 mm; The gas used by the vulcanization compressed air valve in step (2) to pressurize the conveying bin is pure nitrogen, and the water content of the pure nitrogen is ≤0.5%.

7. The method of directly injecting granular sulfur into a fuming furnace for vulcanization according to claim 5, characterized in that: The parameters of the uniform feeder in step (2) are: within 10 minutes of the feed head, starting from 0 t / h, increase by 0.1 t / h every 1 minute, that is, 10 minutes after starting, the feeding speed of the uniform feeder 5 will reach 1.0 t / h, and the feeding speed is kept within 1.0±0.2 t / h for fine adjustment; The weight of the sulfur feed is calculated by the following method: the total weight of the sulfur feed is calculated according to 30%wt of the tin metal content of the tin ore in the fuming furnace, and the excess coefficient is controlled at 5% to 10%.

8. The method of directly injecting granular sulfur into a fuming furnace for sulfurization and volatilization according to claim 5, characterized in that: The parameters of the pulverized coal injection system in step (3) are that the pulverized coal feeding rate is 1.3-1.8 t / h and the conveying air pressure is stable at 3-6 Bar; The particle size control requirements of the pulverized coal are: passing through a 400-mesh sieve, fixed carbon content ≥65%wt, moisture content ≤2.5%wt, ash content ≤15%wt, and volatile matter ≤15%wt.

9. The method of directly injecting granular sulfur into a fuming furnace for vulcanization according to claim 5, characterized in that: Step (2) also includes: after the tin content of the molten slag is ≤0.2%, stopping the uniform feeder, closing the sulfur feed valve after 5 minutes, continuing to keep the nitrogen delivery pipeline valve in the normally open state, keeping the pulverized coal feed into the fuming furnace, adjusting the pulverized coal feed rate at 0.5-1.0 t / h, and observing the temperature monitor at the same time to ensure that the temperature of the rising flue of the fuming furnace is between 1100 and 1150°C. If it is lower or higher than this temperature range, the coal feed rate is increased or decreased by 0.1-0.3 t / h respectively, until the slag in the fuming furnace is completely discharged, stopping the pulverized coal feed, keeping the coal feed air valve in the normally open state, and ensuring that the coal injection burner is not blocked.

10. The method of directly injecting granular sulfur into a fuming furnace for vulcanization according to claim 5, characterized in that: The pulverized coal is replaced by gas of equal combustion value, and the pressure of the gas at the burner end of the fuming furnace is maintained above 4 Bar. Alternatively, the pulverized coal is replaced by mixed lump coal, and the mixed lump coal is delivered to the fuming furnace through a furnace top belt feeding system.

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