Start-up method of roasting furnace for chalcocite

Abstract

This invention discloses a method for starting up a roasting furnace for processing chalcocite. The method uses the furnace bottom ash as the furnace bottom material, which is pre-screened. The airflow during the bottom material laying process is strictly controlled to maintain the material in the hearth in a slightly boiling state. During the furnace regeneration stage, oxygen-enriched air is introduced while the total furnace airflow is controlled to remain in a slightly boiling state. Intermittent turning operations are performed using a medium boiling state. During the boiling layer heating stage, the total airflow is increased to maintain the material in a medium boiling state, and intermittent turning operations are performed using a fully boiling state. This invention initially uses sulfation roasting as the main method for starting up the furnace, then gradually transitions to oxidation roasting. The initial feeding temperature is about 70°C lower than the normal roasting reaction temperature, shortening the heating time and reducing fuel consumption during the heating process. The starting method provided by this invention not only achieves stable start-up but also saves energy.

Description

Technical Field

[0001] This invention relates to the field of copper smelting technology, and in particular, to a method for starting up a roasting furnace for processing chalcocite. Background Technology

[0002] In copper smelting processes both domestically and internationally, pyrometallurgy holds an absolute dominant position, with approximately 85% of the world's primary copper production obtained through pyrometallurgy. However, in the Democratic Republic of Congo (DRC) of Africa, due to severely underdeveloped power infrastructure, a shortage of raw materials needed for slag production in pyrometallurgy, and a lack of skilled pyrometallurgical workers, the hydrometallurgical copper extraction process, which involves roasting, leaching, extraction, and electrowinning, is currently widely used.

[0003] The SICOMINES copper-cobalt mine in the Democratic Republic of Congo employs oxygen-enriched roasting technology to process chalcocite concentrate, producing copper roasted ore that can be used as a raw material for copper extraction in hydrometallurgical plants. This technology features a large roasting furnace capacity, low impurity content in the roasted ore, and high purity of the produced cathode copper, serving as a model for copper concentrate smelting in the region.

[0004] The start-up of a roasting furnace generally includes stages such as laying the bottom material, ignition and heating, and charging. Laying the bottom material primarily aims to provide an initial material bed of sufficient thickness to ensure the material entering the furnace remains in a boiling state during start-up. Ignition and heating primarily aim to raise the temperature of the furnace chamber and the bottom material above the roasting reaction temperature, ensuring the material can react normally during start-up. Currently, publicly available roasting furnace start-up methods mainly focus on pyrite and zinc concentrate roasting, with few reports on start-up methods for chalcocite roasting furnaces. Since its commissioning, SICOMINES' copper-cobalt ore roasting furnace has undergone independent research and exploration, optimizing and innovating the steps of bottom material laying, ignition and heating, and charging multiple times, accumulating rich practical experience and basically achieving safe and stable start-up. However, there have also been process accidents such as furnace bed sintering caused by uneven bottom material laying leading to poor boiling effects after start-up. In addition, there are problems such as slow temperature rise of the furnace bed material layer during ignition and heating, low heating efficiency, and high start-up costs. Summary of the Invention

[0005] This invention provides a method for starting up a roasting furnace for processing chalcocite, in order to solve the technical problems of unstable operation and low success rate in the prior art.

[0006] This invention provides a method for starting up a roasting furnace for processing chalcocite, comprising the following steps:

[0007] S1. Screen the bottom slag of the roasting furnace to obtain bottom material with a particle size of less than 3mm;

[0008] S2, at 1500-2500m 3Air is blown in at a rate of / h to begin laying the furnace bottom material into the furnace bed. During the laying process, the air volume is increased while the material is added to keep the material in the furnace bed in a slightly boiling state. After the material is laid, the static height of the material is 750-850mm. The ratio of the height of the boiling layer to the static height of the material in the slightly boiling state is 1.06-1.

[0009] S3, Furnace heat storage stage: Based on an air volume of 5000-6000 m³ / h... 3 Air is blown into the roasting furnace at a rate of / h, and oxygen-enriched air is introduced simultaneously to maintain the material in a slightly boiling state, thereby increasing the furnace temperature. During the heating process, the oil volume is increased, and the oxygen-enriched air supply is also increased. Specifically, when the furnace temperature is below 780℃, the air volume is adjusted to 12000-13500 m³ / h for every 100℃ increase in furnace temperature. 3 The furnace is turned over once per hour, and the material is kept in a moderate boiling state for 3 to 5 minutes. After the furnace is turned over, the blast volume is restored to 5000 to 6000 m³ / h. 3 / h;

[0010] Boiling layer heating stage: When the furnace temperature reaches 780℃ or above, increase the air volume to 16000-18000 m³ / h. 3 The furnace is rotated at a rate of / h to keep the material in a fully boiling state. Once the furnace temperature drops to 680℃~700℃, the air volume is adjusted to 12000~13500 m³ / h. 3 / h, keeping the material in a moderate boiling state, continue to raise the temperature inside the furnace, and repeat the boiling layer heating stage steps until the material temperature in the furnace bed gradually rises to 680℃~700℃. Among them, the ratio of the material boiling layer height to the material static height is 1.375~1.25 in the fully boiling state; the ratio of the material boiling layer height to the material static height is 1.25~1.06 in the moderate boiling state.

[0011] S4. According to the blower volume of 16000~17000m³ 3 Air is blown into the roasting furnace at a rate of 0.7–1 t / h, while oxygen-enriched air is introduced simultaneously. Granular sulfur and chalcocite slurry are also added to the furnace. The sulfur addition rate is 0.7–1 t / h, and the chalcocite slurry addition rate is 12–14 t / h, to stabilize the fluidized bed temperature at 650℃–700℃. The air flow rate is then gradually increased to 17500–18000 m³ / h. 3 / h; the sulfur addition was reduced to 0.2-0.7t / h; the chalcocite slurry addition was increased to 16-18t / h, so that the boiling layer temperature was maintained at 750-770℃, and the start-up was completed.

[0012] Furthermore, in S1, the slag discharged from the bottom of the roasting furnace has a moisture content of less than 2.5%, contains 57% to 60% copper, and contains 4% to 5.5% sulfur.

[0013] Furthermore, in S2, after the material is laid, the air volume is increased to 18,000–20,000 m³ / h. 3 / h, to allow the material to boil completely and maintain this state for 20-30 minutes.

[0014] Furthermore, in S3, the ventilation rate of simultaneously introduced oxygen-enriched air is 500–625 m³ / h. 3 / h.

[0015] Furthermore, in S3, during the process of raising the furnace temperature, the furnace heating rate is controlled to be 50-80℃ / h.

[0016] Furthermore, in S3, the temperature inside the furnace is increased by supplying oil with an oil gun, which is installed inside the roasting furnace with the oil gun head facing the furnace bed.

[0017] Furthermore, in S4, the ventilation rate of simultaneously introduced oxygen-enriched air is 2000–2500 m³ / h. 3 / h.

[0018] Furthermore, in S4, the concentration of chalcocite slurry is controlled at 75-77%.

[0019] Furthermore, in S4, when the boiling layer temperature is 650℃~700℃, chalcocite is mainly roasted by sulfation, and the sulfur dioxide concentration ranges from 1.5% to 2.5%.

[0020] Furthermore, in S4, when the boiling layer temperature is 750℃~770℃, chalcocite is mainly roasted by oxidation, and the sulfur dioxide concentration ranges from 4.5% to 6%.

[0021] The present invention has the following beneficial effects:

[0022] This invention strictly controls the air volume during the laying of the furnace bottom material to keep the material in the furnace bed in a slightly boiling state, avoids material accumulation at the drop point, ensures that the furnace bottom material is evenly dispersed on the furnace bed, and improves the boiling effect of the material during the subsequent heating process.

[0023] This invention introduces a certain amount of oxygen-enriched air into the furnace during the heat storage stage and controls the total air volume entering the furnace, which can achieve two effects: First, because the oxygen-enriched air has a high oxygen content, it can significantly reduce the total air volume entering the furnace while ensuring the oxygen required for fuel combustion, thereby minimizing the heat carried away by the flue gas and improving the heating efficiency; Second, after the oxygen-enriched air is introduced, the air inside the furnace is in an oxygen-enriched atmosphere, which can promote more complete fuel combustion and improve the thermal efficiency of the fuel.

[0024] This invention features a low total air volume during the furnace heating and heat storage stage, keeping the material in a slightly boiling state and intermittently using a medium boiling state for furnace turning operations. This not only rapidly increases the furnace temperature but also prevents the surface material from sintering due to continuous high-temperature heat radiation during the heating process. During the boiling layer heating stage, the total air volume is increased to maintain the material in a medium boiling state, and furnace turning operations are intermittently using a fully boiling state. This significantly improves the heat exchange efficiency between materials and rapidly increases the material temperature in the boiling layer.

[0025] During the start-up process, the blast volume at the bottom of the furnace is slightly lower than the blast volume when the furnace bed is fully boiling. Sulfur is added in a timely manner to maintain the heat of the system and the initial ore feed is controlled to be 75% to 85% of the normal production. This invention effectively solves the problem of excessive heat loss in the system during the period from the start-up of the blower to the complete reaction of the material, and avoids the furnace bed temperature from dropping below the reaction point, which would lead to start-up failure.

[0026] This invention employs a pre-treatment roasting method, primarily using sulfation roasting followed by a gradual transition to oxidative roasting. The initial feed temperature is approximately 70°C lower than the normal roasting reaction temperature, shortening the heating time and reducing fuel consumption during the heating process. Simultaneously, the sulfur dioxide concentration gradually increases during startup, facilitating the control of acid production exhaust gases and achieving environmentally friendly startup. Detailed Implementation

[0027] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described in this specification are merely illustrative of the invention and are not intended to limit the invention.

[0028] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0029] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, "multiple" in "one or more" means two or more, and "more than" in "one or more" means two or more.

[0030] This invention provides a method for starting up a roasting furnace for processing chalcocite, comprising the following steps:

[0031] S1. Screen the bottom slag of the roasting furnace to obtain bottom material with a particle size of less than 3mm;

[0032] S2, at 1500-2500m 3 Air is blown in at a rate of / h to begin laying the furnace bottom material into the furnace bed. During the laying process, the air volume is increased while the material is added to keep the material in the furnace bed in a slightly boiling state. After the material is laid, the static height of the material is 750-850mm. The ratio of the height of the boiling layer to the static height of the material in the slightly boiling state is 1.06-1.

[0033] S3, Furnace heat storage stage: Based on an air volume of 5000-6000 m³ / h... 3 Air is blown into the roasting furnace at a rate of / h, and oxygen-enriched air is introduced simultaneously to maintain the material in a slightly boiling state, thereby raising the furnace temperature. During the heating process, the oil volume is increased while the oxygen-enriched air volume is increased. Specifically, when the furnace temperature is below 780℃, the blower volume is adjusted to 12000–13500 m³ / h for every 100℃ increase in furnace temperature. 3 The furnace is turned over once per hour, and the material is kept in a moderate boiling state for 3 to 5 minutes. After the furnace is turned over, the blast volume is restored to 5000 to 6000 m³ / h. 3 / h;

[0034] Boiling layer heating stage: When the furnace temperature reaches 780℃ or above, increase the air volume to 16000-18000 m³ / h. 3 The furnace is rotated at a rate of / h to keep the material in a fully boiling state. Once the furnace temperature drops to 680℃~700℃, the air volume is adjusted to 12000~13500 m³ / h. 3 / h, keeping the material in a moderate boiling state, continue to raise the temperature inside the furnace, and repeat the boiling layer heating stage steps until the material temperature in the furnace bed gradually rises to 680℃~700℃. Among them, the ratio of the material boiling layer height to the material static height is 1.375~1.25 in the fully boiling state; the ratio of the material boiling layer height to the material static height is 1.25~1.06 in the moderate boiling state.

[0035] S4. According to the blower volume of 16000~17000m³ 3 Air is blown into the roasting furnace at a rate of 0.7–1 t / h, while oxygen-enriched air is introduced simultaneously. Granular sulfur and chalcocite slurry are also added to the furnace. The sulfur addition rate is 0.7–1 t / h, and the chalcocite slurry addition rate is 12–14 t / h, to stabilize the fluidized bed temperature at 650℃–700℃. The air flow rate is then gradually increased to 17500–18000 m³ / h. 3 / h; the sulfur addition was reduced to 0.2-0.7t / h; the chalcocite slurry addition was increased to 16-18t / h, so that the boiling layer temperature was maintained at 750-770℃, and the start-up was completed.

[0036] According to an embodiment of this application, when the particle size in S1 is greater than or equal to 3mm, excessively large bottom material will affect the boiling effect of the material.

[0037] According to the embodiments of this application, in step S2, the furnace bottom material is laid with air. During the laying process, a certain initial air volume is supplied, and the furnace bottom air volume is increased according to the laying amount, so that the material is always kept in a slightly boiling state, which facilitates the uniform dispersion of the material on the furnace bed. If the laying is not done with air, or the air volume is not appropriate, the furnace bottom material will easily accumulate locally, resulting in poor boiling effect in this area during production.

[0038] According to the embodiments of this application, in the initial stage of the furnace heat storage stage of S3, a low air volume is supplied and oxygen-enriched air is introduced to keep the material in a slightly boiling state. The purpose is to reduce the total air volume and reduce the heat carried away by the flue gas while ensuring sufficient oxygen supply, thereby improving the heating efficiency.

[0039] According to the embodiments of this application, in the boiling layer heating stage of S3, the material is kept in a moderate boiling state. When the furnace temperature reaches 780-800°C, a large air volume is used to make the material fully boil, thereby improving the heat transfer efficiency between materials and promoting the increase of the material layer temperature.

[0040] According to the embodiments of this application, in S4, during the initial feeding stage, the furnace bottom blast volume is slightly lower than the blast volume when the furnace bed is fully boiling, and sulfur is added in a timely manner to maintain system heat. The initial ore feed is controlled to be 75-85% of normal production, which effectively solves the problem of excessive heat loss in the system during the period from start-up of the blower to complete material reaction, and avoids the furnace bed temperature dropping below the reaction point, leading to start-up failure. The initial feeding start-up mainly uses sulfation roasting (boiling layer temperature 650℃-700℃), and then gradually switches to oxidative roasting (boiling layer temperature 750℃-770℃). The initial feeding temperature is about 70℃ lower than the normal roasting reaction temperature, shortening the heating time and reducing fuel consumption during the heating process. Simultaneously, the sulfur dioxide concentration increases from low to high during start-up, which is beneficial for controlling acid production tail gas and achieving environmentally friendly start-up.

[0041] In the embodiments of this application, in S1, the slag discharged from the bottom of the roasting furnace has a moisture content of less than 2.5%, contains 57% to 60% copper, and contains 4% to 5.5% sulfur. The bottom material is selected from roasted slag clinker with low sulfur content, which minimizes the generation of sulfur dioxide during the heating process and reduces the cost of waste gas treatment.

[0042] In the embodiments of this application, in S2, after the material is laid, the air volume is increased to 18,000-20,000 m³ / h. 3The material is boiled completely at a constant temperature ( / h) and maintained for 20–30 minutes. In this fully boiled state, the material has better fluidity, allowing for a more uniform distribution of the material layer on the furnace bed. Uneven material layer distribution can lead to poor boiling in areas with thicker layers during start-up or production, easily resulting in localized sintering.

[0043] In the embodiments of this application, in S3, the ventilation rate of the simultaneously introduced oxygen-enriched air is 500-625 m³ / h. 3 / h. The oxygen concentration in the above-mentioned oxygen-enriched air can be selected as 80%, or about 80%. This oxygen-enriched air contains about 3.8 times the oxygen of air. Under the premise of ensuring the oxygen required for fuel combustion, the total air volume entering the furnace can be significantly reduced, the heat carried away by the flue gas can be minimized, and the heating efficiency can be improved.

[0044] In the embodiments of this application, during step S3, the furnace temperature is increased at a rate of 50–80 °C / h. Since the furnace is lined with refractory bricks, moisture will be absorbed between the bricks after shutdown. An excessively rapid temperature increase will affect the service life of the refractory bricks; an excessively slow temperature increase will affect start-up time and waste fuel.

[0045] In the embodiments of this application, in step S3, the furnace temperature is increased by supplying oil using oil guns. The oil guns are positioned inside the roasting furnace, with their heads facing the furnace bed. The oil guns are evenly and symmetrically distributed around the circumference of the roasting furnace, and the oil gun heads are approximately 3 meters above the furnace bed. The oil supply rate is adjustable; the number of guns activated and the amount of oil supplied are determined based on the furnace heating rate.

[0046] According to an embodiment of this application, in S3, oxygen-enriched air enters the roasting furnace air chamber together with the bottom air, which provides linear velocity for the boiling of materials and also plays a role in combustion.

[0047] In the embodiments of this application, in S4, the ventilation rate of the simultaneously introduced oxygen-enriched air is 2000-2500 m³ / h. 3 / h. The ordinary air and oxygen-enriched air introduced into the roasting furnace serve two purposes: firstly, to provide the linear velocity required for boiling of the material in the furnace bed; only when the total air volume reaches a certain level can the material in the furnace bed achieve complete boiling; secondly, the oxygen content in the total air volume must meet the oxygen requirements of the roasting reaction. Under the premise of meeting these two process requirements, the amount of ordinary air should be minimized, and the amount of oxygen-enriched air should be maximized. The oxygen-enriched air flow rate in S4 is 2000–2500 m³ / h. 3 / h can meet the above requirements.

[0048] In the embodiments of this application, in S4, the concentration of chalcocite slurry is controlled at 75-77%. If the slurry concentration is too high, the slurry is difficult to transport and is very likely to clog the pipeline; if the slurry concentration is too low, the water content in the slurry is high, resulting in a high amount of water introduced into the system and a high water content in the flue gas, which is very likely to produce dilute acid and cause serious corrosion to downstream equipment.

[0049] In the embodiments of this application, in S4, when the boiling layer temperature is 650°C to 700°C, chalcocite is mainly roasted by sulfation, and the sulfur dioxide concentration ranges from 1.5% to 2.5%. In S4, when the boiling layer temperature is 750°C to 770°C, chalcocite is mainly roasted by oxidation, and the sulfur dioxide concentration ranges from 4.5% to 6%.

[0050] According to the embodiments of this application, the initial feeding and start-up of this invention mainly involves sulfation roasting, which is then gradually converted to oxidative roasting. The initial feeding temperature is about 70°C lower than the normal roasting reaction temperature, shortening the heating time and reducing fuel consumption during the heating process. Simultaneously, the sulfur dioxide concentration gradually increases during start-up, which is beneficial for controlling the acid production tail gas and achieving environmentally friendly start-up.

[0051] In the embodiments of this application, the method for starting up a roasting furnace for processing chalcocite includes the following steps:

[0052] S1, screening furnace bottom material

[0053] The bottom slag (calcined sand) from the calcining furnace is used as the bottom material. The bottom material particles are loose, with a moisture content of less than 2.5%, a copper content of 57% to 60%, and a sulfur content of 4% to 5.5%. The bottom material is screened using screening equipment to ensure that the particle size is less than 3mm.

[0054] By strictly controlling the particle size and moisture content of the furnace bottom material, the material is prevented from accumulating at the drop point due to gravity during subsequent furnace bottom material laying. This ensures that the furnace bottom material is evenly dispersed on the furnace bed, improving the boiling effect of the material during subsequent heating. Selecting low-sulfur roasted clinker for the furnace bottom material minimizes the generation of sulfur dioxide during heating, reducing waste gas treatment costs.

[0055] For newly built roasting furnaces, river sand or quartz sand can also be used as furnace bottom material, and the particle size and moisture content must meet the above requirements.

[0056] S2, Laying furnace bottom material

[0057] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 1500–2500 m³ / h. 3 / h, the furnace bottom material is thrown into the furnace bed using a throwing device. During this process, every 10m... 3 After the furnace bottom charge is applied, the furnace bottom blast volume will be increased by 2000 m³ / h. 3 / h. After the furnace bottom material is laid, increase the air volume to 18,000-20,000 m³ / h. 3 / h, keep the material in a fully boiling state on the furnace bed for 20-30 minutes to ensure that the material is evenly distributed on the furnace bed. After this step, the static height of the material on the furnace bed is controlled at 750-850mm.

[0058] The above method keeps the furnace bottom material in a state of slight boiling, and the material creeps towards the furnace bed under the action of the bottom air, improving the uniformity of the furnace bottom material. Compared with the traditional method of laying the furnace bottom material without air, the material layer is looser and the later boiling effect is better.

[0059] S3, Ignition and Heating

[0060] Phase 1: Furnace Heat Regeneration Phase

[0061] By opening the bypass flue gas duct at the furnace top, the flue gas bypasses the waste heat boiler, electrostatic precipitator, and electrostatic demister. This solution avoids pollution of the electrostatic precipitator and electrostatic demister by oil in the flue gas during the heating process due to incomplete fuel combustion.

[0062] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 5000–6000 m³. 3 / h, oxygen-enriched air with an oxygen concentration of 80% is simultaneously introduced into the air chamber at a depth of 500-625m. 3 / h, to keep the material on the furnace bed in a slightly boiling state.

[0063] By introducing a certain amount of oxygen-enriched air and controlling the total air volume entering the furnace, two effects can be achieved: First, since the oxygen content of oxygen-enriched air is about 3.8 times that of air, the total air volume entering the furnace can be significantly reduced while ensuring the oxygen required for fuel combustion, thereby minimizing the heat carried away by the flue gas and improving the heating efficiency. Second, after introducing oxygen-enriched air, the air inside the furnace is in an oxygen-enriched atmosphere, which can promote more complete fuel combustion and improve the thermal efficiency of the fuel.

[0064] Initially, one oil gun was used for heating, and then the number was gradually increased to four. For each additional oil gun, the oxygen-enriched air volume increased by 500–625 m³. 3 / h. During this process, the furnace temperature rise rate above the boiling layer is controlled at 50–80℃ / h. For every 100℃ increase in furnace temperature, the furnace bottom blast volume is adjusted to 12000–13500 m³ / h. 3 The furnace is turned over once per hour to keep the material in a moderate boiling state for 3 to 5 minutes, preventing the surface material from sintering due to prolonged high-temperature radiation. After the furnace is turned over, the air volume is restored to the initial value.

[0065] With the above scheme, the total air volume entering the furnace during the heat storage stage of the heating furnace is low, the material is kept in a slightly boiling state, and the furnace is turned over intermittently in a medium boiling state. This can not only achieve the effect of rapidly increasing the furnace temperature, but also prevent the surface material from sintering due to continuous high temperature heat radiation during the heating process.

[0066] Phase Two: Heating Stage of the Boiling Layer

[0067] Once the furnace temperature reaches 780–800℃, increase the air volume to 16,000–18,000 m³ / h. 3 At a rate of / h, the furnace is turned over, during which the material in the furnace bed is in a state of complete boiling. The temperature of the material in the furnace bed is increased through thermal radiation from the furnace and heat exchange between the materials. When the furnace temperature drops to 680℃~700℃, the blast volume is restored to 12000~13500 m³ / h. 3 / h, the material in the furnace bed is kept in a moderate boiling state.

[0068] By increasing the total air volume into the furnace during the heating stage of the boiling layer, keeping the material in a moderate boiling state, and intermittently using a fully boiling state for furnace turning operations, the heat exchange efficiency between materials can be significantly improved, and the material temperature in the boiling layer can be rapidly increased.

[0069] Repeat the above steps to gradually raise the temperature of the material in the furnace bed to 680℃~700℃.

[0070] Stop supplying oil to the oil gun, purge the oil gun, remove the oil gun, stop the oxygen-enriched air, stop the furnace bottom fan and the furnace starter fan, close the furnace top bypass flue gas pipe, keep the flue gas pipes between the roasting furnace, waste heat boiler, electrostatic precipitator and electrostatic demister unobstructed, and the heating process is complete.

[0071] S4, Feeding and Start-up

[0072] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 16,000–17,000 m³. 3 / h, oxygen-enriched air with an oxygen concentration of 80% is simultaneously introduced into the air chamber at a depth of 2000-2500m. 3 At a rate of 0.7–1 t / h, granular sulfur is added to the fluidized bed furnace. Simultaneously, two feed guns are activated to inject chalcocite slurry into the roasting furnace, with an initial feed rate of 12–14 t / h. The fluidized bed temperature initially decreases slowly and gradually stabilizes, but remains above 650℃. Then, the other two feed guns are activated, gradually increasing the air volume, feed rate, and sulfur addition, causing the fluidized bed temperature to rise. Finally, the air volume is increased to 17500–18000 m³ / h. 3 The ore feed rate was increased to 16-18 t / h, the sulfur addition was reduced to 0.2-0.7 t / h, and the boiling layer temperature was controlled at 750-770℃. Start-up was completed.

[0073] Through the above scheme, during the start-up process, the bottom blast volume is slightly lower than that required for complete boiling of the furnace bed, and sulfur is added in a timely manner to maintain system heat. The initial ore feed rate is controlled at 75% of normal production, effectively solving the problem of excessive heat loss during the period from fan startup to complete material reaction, and preventing the furnace bed temperature from dropping below the reaction point and causing ignition failure. Start-up initially focuses on sulfation roasting, gradually transitioning to oxidative roasting. The initial feed temperature is approximately 70°C lower than the normal roasting reaction temperature, shortening the heating time and reducing fuel consumption during the heating process. Simultaneously, the sulfur dioxide concentration gradually increases during start-up, which is beneficial for controlling acid production tail gas and achieving environmentally friendly start-up.

[0074] Example

[0075] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0076] Example 1

[0077] This embodiment provides a 50m 2 The start-up method for a roasting furnace under oxygen-enriched conditions includes the following steps:

[0078] S1, screening furnace bottom material

[0079] The bottom slag (calcined sand) from the calcining furnace was used as the bottom material. The bottom material particles were loose, with a moisture content of 2.1%, a copper content of 57.2%, and a sulfur content of 4.7%. The bottom material was screened using screening equipment, and the average particle size was 0.193 mm, with the largest particle size being 2.5 mm.

[0080] S2, Laying furnace bottom material

[0081] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 1800 m³. 3 / h, the furnace bottom material is thrown into the furnace bed using a throwing device. A total of 41.15m³ of furnace bottom material was laid this time. 3 The laying depth is 0-10m. 3 At that time, the furnace bottom blast volume was 1800 m³ / h. 3 / h; laying amount is 10-20m 3 At that time, the furnace bottom blast volume was 3800 m³. 3 / h; laying distance is 20-30m 3 At that time, the furnace bottom blast volume was 5800 m³ / h.3 / h; laying distance is 30-40m 3 At that time, the furnace bottom blast volume was 7800 m³ / h. 3 / h; laying distance is 40~41.15m 3 At that time, the furnace bottom blast volume was 9800 m³ / h. 3 / h. After the furnace bottom material is laid, the air volume will be increased to 19500m³. 3 / h, keeping the material on the furnace bed in a fully boiling state for 24 minutes. After this step, the static height of the material on the furnace bed is 823mm.

[0082] S3, Ignition and Heating

[0083] Phase 1: Furnace Heat Regeneration Phase

[0084] Open the bypass flue gas duct at the top of the furnace, ensuring the flue gas bypasses the waste heat boiler, electrostatic precipitator, and electrostatic demister. Blow air into the roasting furnace air chamber, with an initial air volume of 5000 m³ / h. 3 / h, 550m³ of oxygen-enriched air with an oxygen concentration of 80% is simultaneously introduced into the air chamber. 3 / h, to keep the material on the furnace bed in a slightly boiling state.

[0085] The initial furnace temperature was 28℃. A single oil gun was used for heating, with an oil supply rate of 202 L / h. After 1.5 hours, the furnace temperature reached 129℃. Then, two oil guns were used for heating, each with an oil supply rate of 215 L / h, and the oxygen-enriched air volume was adjusted to 1100 m³ / h. 3 After 2 hours, the furnace temperature reached 265℃; then, a three-barrel oil gun was used for heating, with an oil supply rate of 215L / h for each gun and an oxygen-enriched air volume adjusted to 1650m³ / h. 3 / h, after 2 hours, the furnace temperature rose to 413℃; then, a four-barrel oil gun was used for heating, and the oxygen-enriched air volume was adjusted to 2200m³. 3 The oil supply rate of the oil guns was 253 L / h. After 4 hours, the furnace temperature rose to 718℃. The heating process continued with four oil guns, increasing the oil supply rate to 317 L / h, while maintaining an oxygen-enriched air volume of 2200 m³ / h. 3 / h, after 1 hour, the furnace temperature rises to 792℃.

[0086] During this process, for every 100°C increase in furnace temperature, the furnace bottom blast volume is adjusted to 12500 m³ / h. 3 The furnace is turned over once per hour to keep the material in a moderate boiling state for 3 minutes. After the furnace is turned over, the air volume is restored to the initial value.

[0087] Phase Two: Heating Stage of the Boiling Layer

[0088] Increase the air volume to 16300m³ 3At a rate of / h, the furnace is turned over, during which the material in the furnace bed is in a state of complete boiling. The temperature of the material in the furnace bed is increased through thermal radiation from the furnace and heat exchange between the materials. When the furnace temperature drops to 690℃, the blast volume is restored to 12500 m³ / h. 3 / h, the material in the furnace bed is kept in a moderate boiling state.

[0089] During this process, the oil supply rate from the oil gun was maintained at 317 L / h, and the oxygen-enriched air volume was maintained at 2200 m³ / h. 3 / h.

[0090] Repeat the above steps, and after 4 hours, gradually raise the temperature of the material in the furnace bed to 690℃.

[0091] Stop supplying oil to the oil gun, purge the oil gun, remove the oil gun, stop the oxygen-enriched air, stop the furnace bottom fan and the furnace starter fan, close the furnace top bypass flue gas pipe, keep the flue gas pipes between the roasting furnace, waste heat boiler, electrostatic precipitator and electrostatic demister unobstructed, and the heating process is complete.

[0092] S4, Feeding and Start-up

[0093] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 16,300 m³. 3 / h, 2200m³ of oxygen-enriched air with an oxygen concentration of 80% is simultaneously introduced into the air chamber. 3 At a rate of 0.75 t / h, granular sulfur is added to the fluidized bed furnace. Simultaneously, two feed guns are activated to inject chalcocite slurry into the roasting furnace. The slurry concentration is 76.2%, and the initial feed rate is 12.8 t / h. The fluidized bed temperature initially decreases slowly and gradually stabilizes, eventually maintaining a temperature of 659℃, with a sulfur dioxide concentration ranging from 1.7% to 2.4%. Then, two more feed guns are activated, gradually increasing the airflow, feed rate, and sulfur addition, causing the fluidized bed temperature to rise. The final airflow is increased to 17500 m³ / h. 3 / h, the ore feed rate increased to 16.7t / h, the sulfur addition decreased to 0.25t / h, the boiling layer temperature was controlled at 763℃, and the sulfur dioxide concentration ranged from 4.5% to 5.6%. Start-up was completed.

[0094] In this embodiment, the driving time is 14.5 hours, and the diesel consumption is 12,841 liters.

[0095] Example 2

[0096] This embodiment provides a 50m 2 The start-up method for a roasting furnace under oxygen-enriched conditions includes the following steps:

[0097] S1, screening furnace bottom material

[0098] The bottom slag (calcined sand) from the calcining furnace was used as the bottom material. The bottom material particles were loose, with a moisture content of 2.3%, a copper content of 59.7%, and a sulfur content of 5.3%. The bottom material was screened using screening equipment, and the average particle size was 0.19 mm, with the largest particle size being 2.8 mm.

[0099] S2, Laying furnace bottom material

[0100] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 2000 m³ / h. 3 / h, the furnace bottom material is thrown into the furnace bed using a throwing device. A total of 42m³ of furnace bottom material was laid this time. 3 The laying depth is 0-10m. 3 At that time, the furnace bottom blast volume was 2000 m³ / h. 3 / h; laying amount is 10-20m 3 At that time, the furnace bottom blast volume was 4000 m³ / h. 3 / h; laying distance is 20-30m 3 At that time, the furnace bottom blast volume was 6000 m³ / h. 3 / h; laying distance is 30-40m 3 At that time, the furnace bottom blast volume was 8000 m³ / h. 3 / h; laying distance is 40-42m 3 At that time, the furnace bottom blast volume was 10000 m³. 3 / h. After the furnace bottom material is laid, the air volume will be increased to 19500m³. 3 / h, keeping the material on the furnace bed in a fully boiling state for 28 minutes. After this step, the static height of the material on the furnace bed is 840mm.

[0101] S3, Ignition and Heating

[0102] Phase 1: Furnace Heat Regeneration Phase

[0103] Open the bypass flue gas duct at the top of the furnace, ensuring the flue gas bypasses the waste heat boiler, electrostatic precipitator, and electrostatic demister. Blow air into the roasting furnace air chamber with an initial air volume of 5800 m³ / h. 3 / h, 520m³ of oxygen-enriched air with an oxygen concentration of 80% is simultaneously introduced into the air chamber. 3 / h, to keep the material on the furnace bed in a slightly boiling state.

[0104] The initial furnace temperature was 30℃. A single oil gun was used for heating, with an oil supply rate of 204 L / h. After 1.5 hours, the furnace temperature reached 128℃. Then, two oil guns were used for heating, each with an oil supply rate of 213 L / h, and the oxygen-enriched air volume was adjusted to 1040 m³ / h. 3 After 2 hours, the furnace temperature reached 259℃; then, a three-barrel oil gun was used for heating, with an oil supply rate of 213L / h for each gun and an oxygen-enriched air volume adjusted to 1560m³ / h. 3 / h, after 2 hours, the furnace temperature rose to 402℃; then, a four-barrel oil gun was used for heating, and the oxygen-enriched air volume was adjusted to 2080m³ / h. 3 The oil supply rate of the oil guns was 257 L / h. After 4 hours, the furnace temperature rose to 798℃. The heating process continued with four oil guns, increasing the oil supply rate to 320 L / h and maintaining the oxygen-enriched air volume at 2080 m³ / h. 3 / h, after 1.5h, the furnace temperature rises to 795℃.

[0105] During this process, for every 100°C increase in furnace temperature, the furnace bottom blast volume is adjusted to 13200 m³ / h. 3 The furnace is turned over once per hour to keep the material in a moderate boiling state for 3.5 minutes. After the furnace is turned over, the air volume is restored to the initial value.

[0106] Phase Two: Heating Stage of the Boiling Layer

[0107] Increase the air volume to 17000m³ 3 At a rate of / h, a furnace turning operation is performed. During this time, the material in the furnace bed is in a fully boiling state, and the temperature of the material in the furnace bed is increased through thermal radiation from the furnace and heat exchange between the materials. Once the furnace temperature drops to 690℃, the blast volume is restored to 13200 m³ / h. 3 / h, the material in the furnace bed is kept in a moderate boiling state.

[0108] During this process, the oil supply rate of the oil gun is maintained at 320L / h, and the oxygen-enriched air volume is maintained at 2080m³. 3 / h.

[0109] Repeat the above steps, and after 4.7 hours, gradually raise the temperature of the material in the furnace bed to 697℃.

[0110] Stop supplying oil to the oil gun, purge the oil gun, remove the oil gun, stop the oxygen-enriched air, stop the furnace bottom fan and the furnace starter fan, close the furnace top bypass flue gas pipe, keep the flue gas pipes between the roasting furnace, waste heat boiler, electrostatic precipitator and electrostatic demister unobstructed, and the heating process is complete.

[0111] S4, Feeding and Start-up

[0112] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 17,000 m³. 3 / h, 2200m³ of oxygen-enriched air with an oxygen concentration of 80% is simultaneously introduced into the air chamber. 3At a rate of 0.83 t / h, granular sulfur is added to the fluidized bed furnace. Simultaneously, two feed guns are activated to inject chalcocite slurry into the roasting furnace. The slurry concentration is 76.5%, and the initial feed rate is 13.4 t / h. The fluidized bed temperature initially decreases slowly and gradually stabilizes, eventually maintaining a temperature of 667℃, with a sulfur dioxide concentration ranging from 2% to 2.4%. Then, two more feed guns are activated, gradually increasing the airflow, feed rate, and sulfur addition, causing the fluidized bed temperature to rise. The final airflow is increased to 18000 m³ / h. 3 / h, the ore feed rate increased to 17.4t / h, the sulfur addition decreased to 0.22t / h, the boiling layer temperature was controlled at 768℃, and the sulfur dioxide concentration ranged from 4.6% to 5.8%. Start-up was completed.

[0113] In this embodiment, the driving time was 15.7 hours, and the diesel consumption was 14484L.

[0114] Comparative Example

[0115] This comparative example provides a 50m 2 The specific steps for starting up a roasting furnace in a non-oxygen-enriched state are as follows:

[0116] S1, screening furnace bottom material

[0117] The bottom slag (calcined sand) from the calcining furnace was used as the bottom material. The bottom material particles were loose, with a moisture content of 2.3%, a copper content of 58.8%, and a sulfur content of 4.8%. The bottom material was screened using screening equipment, and the average particle size was 0.195 mm, with the largest particle size being 2.8 mm.

[0118] S2, Laying furnace bottom material

[0119] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 2300 m³ / h. 3 / h, the furnace bottom material is thrown into the furnace bed using a throwing device. A total of 39.75m³ of furnace bottom material was laid this time. 3 The laying depth is 0-10m. 3 At that time, the furnace bottom blast volume was 2300 m³ / h. 3 / h; laying amount is 10-20m 3 At that time, the furnace bottom blast volume was 4300 m³ / h. 3 / h; laying distance is 20-30m 3 At that time, the furnace bottom blast volume was 6300 m³ / h. 3 / h; laying distance is 30-39.75m 3 At that time, the furnace bottom blast volume was 8300 m³ / h. 3 / h. After the furnace bottom material is laid, the air volume will be increased to 19500m³. 3 / h, keeping the material on the furnace bed in a fully boiling state for 25 minutes. After this step, the static height of the material on the furnace bed is 795mm.

[0120] S3, Ignition and Heating

[0121] Phase 1: Furnace Heat Regeneration Phase

[0122] Open the bypass flue gas duct at the top of the furnace, ensuring the flue gas bypasses the waste heat boiler, electrostatic precipitator, and electrostatic demister. Blow air into the roasting furnace air chamber at an initial air volume of 6500 m³ / h. 3 / h, to keep the material on the furnace bed in a slightly boiling state.

[0123] The initial furnace temperature was 31℃. One oil gun was used for heating at a rate of 220L / h. After 1.5 hours, the furnace temperature reached 121℃. Then, two oil guns were used for heating, each with a supply rate of 220L / h, and the air volume was adjusted to 8000m³ / h. 3 After 2 hours, the furnace temperature reached 244℃; then, a three-barrel oil gun was used for heating, with an oil supply rate of 220L / h for each gun and an air volume adjusted to 9500m³ / h. 3 / h, after 2 hours, the furnace temperature rose to 376℃; then, a four-barrel oil gun was used for heating, and the air volume was adjusted to 11000m³ / h. 3 The oil supply rate of the oil guns was 270L / h. After 4 hours, the furnace temperature rose to 650℃. The heating process continued with four oil guns, increasing the oil supply rate to 350L / h and maintaining the air volume at 11000m³ / h. 3 / h, after 2.8h, the furnace temperature rose to 791℃.

[0124] During this process, for every 100°C increase in furnace temperature, the furnace bottom blast volume is adjusted to 15500 m³ / h. 3 The furnace is turned over once per hour to keep the material in a moderate boiling state for 5 minutes. After the furnace is turned over, the air volume is restored to the initial value.

[0125] Phase Two: Heating Stage of the Boiling Layer

[0126] Increase the air volume to 19300m³ 3 At a rate of / h, the furnace is turned over, during which the material in the furnace bed is in a state of complete boiling. The temperature of the material in the furnace bed is increased through thermal radiation from the furnace and heat exchange between the materials. When the furnace temperature drops to 690℃, the blast volume is restored to 15500 m³ / h. 3 / h, the material in the furnace bed is kept in a moderate boiling state.

[0127] During this process, the oil supply rate of the oil gun is maintained at 350L / h, and the oxygen-enriched air volume is maintained at 2080m³. 3 / h.

[0128] Repeat the above steps, and after 5.6 hours, gradually raise the temperature of the material in the furnace bed to 688℃.

[0129] Stop supplying oil to the oil gun, purge the oil gun, remove the oil gun, stop the oxygen-enriched air, stop the furnace bottom fan and the furnace starter fan, close the furnace top bypass flue gas pipe, keep the flue gas pipes between the roasting furnace, waste heat boiler, electrostatic precipitator and electrostatic demister unobstructed, and the heating process is complete.

[0130] S4, Feeding and Start-up

[0131] Air is blown into the air chamber of the roasting furnace, with an initial air volume of 16,800 m³. 3 / h, 2500m³ of oxygen-enriched air with an oxygen concentration of 80% is simultaneously introduced into the air chamber. 3 At a rate of 0.91 t / h, granular sulfur was added to the fluidized bed furnace. Simultaneously, two feed guns were activated to inject chalcocite slurry into the roasting furnace. The slurry concentration was 76.2%, and the initial feed rate was 12.8 t / h. The fluidized bed temperature initially decreased slowly and gradually stabilized, eventually maintaining a temperature of 673℃, with a sulfur dioxide concentration ranging from 1.8% to 2.3%. Then, the other two feed guns were activated, gradually increasing the airflow, feed rate, and sulfur addition, causing the fluidized bed temperature to rise. The final airflow was increased to 17400 m³ / h. 3 / h, the ore feed rate increased to 17.2t / h, the sulfur addition decreased to 0.33t / h, the boiling layer temperature was controlled at 766℃, and the sulfur dioxide concentration ranged from 4.8% to 5.7%. Start-up was completed.

[0132] In this embodiment, the driving time is 17.9 hours and the diesel consumption is 18610L.

[0133] Both Examples 1 and 2 involve ignition and heating under conditions of both ordinary air and oxygen-enriched air, with a total air volume of 7200–7880 m³ / h during the furnace heat storage stage. 3 / h; The comparative example involves ignition and heating under normal air conditions, with a total air volume of 11000 m³ / h during the furnace heat storage stage. 3 / h. Example 1 saves 3.4 hours of driving time, 5769L of diesel consumption, and 39806 yuan of driving cost compared to the comparative method; Example 2 saves 2.2 hours of driving time, 4126L of diesel consumption, and 28469 yuan of driving cost compared to the comparative method (calculated at a diesel price of 6.9 yuan / L).

[0134] Practice has proven that the start-up method for a chalcocite roasting furnace provided by this invention saves approximately 12% to 19% of the start-up time and 22% to 31% of the start-up cost compared to traditional start-up methods. It not only achieves stable start-up but also saves energy.

[0135] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method of starting up a roaster for treating chalcocite, characterized by, The method comprises the following steps: S1, screening the roaster bottom slag to obtain a roaster bottom material with a particle size less than 3 mm; S2, with 1500-2500 m 3 blowing air at a rate of 1500-2500 m3 / h is blown into the hearth to start laying the hearth material as the material, during the laying process, the material is increased while the blowing rate is increased, so that the material in the hearth always maintains a slightly boiling state, and after the laying is completed, the static height of the material is 750-850 mm, wherein the ratio of the boiling layer height of the material in the slightly boiling state to the static height of the material is 1.06-1.

06. S3, hearth regenerative stage: air is blown into the roaster at a rate of 5000-6000 m 3 / h, and oxygen-enriched air is simultaneously introduced to keep the material in a slightly boiling state, and to raise the hearth temperature. During the temperature rising process, the oil quantity is increased while the oxygen-enriched air quantity is also increased. When the hearth temperature is below 780°C, the air quantity is adjusted to 12000-13500 m 3 / h per 100°C increase in the hearth temperature. The material is kept in a moderately boiling state for 3-5 minutes by turning over the material once, and then the air quantity is returned to 5000-6000 m 3 / h. Boiling layer temperature rising stage: when the furnace temperature rises to 780℃ and above, the blast volume is increased to 16000-18000 m 3 / h, so that the material is kept in a fully boiling state; when the furnace temperature decreases to 680-700℃, the blast volume is adjusted to 12000-13500 m 3 / h, so that the material is kept in a moderate boiling state; the temperature in the furnace is continuously increased, and the steps of the boiling layer temperature rising stage are repeated until the material temperature in the furnace bed gradually rises to 680-700℃, wherein the fully boiling state is a ratio of the material boiling layer height to the material static height of 1.375-1.25; the moderate boiling state is a ratio of the material boiling layer height to the material static height of 1.25-1.06; S4, the blast volume is 16000~17000m 3 / h, the oxygen-enriched air is synchronously introduced, the granular sulfur and chalcocite slurry are added into the roasting furnace, the sulfur addition amount is 0.7~1t / h, the chalcocite slurry addition amount is 12~14t / h, so that the boiling layer temperature is stably kept at 650~700℃, and then the blast volume is gradually increased to 17500~18000m 3 / h; the sulfur addition amount is reduced to 0.2~0.7t / h; the chalcocite slurry addition amount is increased to 16~18t / h, so that the boiling layer temperature is kept at 750~770℃, and the starting is completed.

2. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S1, the roaster bottom slag has a water content less than 2.5%, a copper content of 57% to 60%, and a sulfur content of 4% to 5.5%.

3. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S2, after the material is laid, the blast volume is increased to 18000-20000 m 3 / h, so that the material is completely boiled, and is kept for 20-30 min.

4. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S3, the ventilation volume of the oxygen-enriched air is 500-625 m 3 / h.

5. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S3, the temperature of the hearth is raised at a speed of 50 to 80 ℃ / h.

6. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S3, the temperature of the hearth is raised by means of an oil gun, which is arranged in the roaster and has a head directed toward the hearth.

7. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S4, the ventilation volume of the oxygen-enriched air is 2000-2500 m 3 / h.

8. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S4, the concentration of the chalcocite slurry is controlled to be 75 to 77%.

9. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S4, when the temperature of the fluidized layer is 650 to 700 ℃, the chalcocite is mainly sulfurized, and the concentration of sulfur dioxide gas is 1.5% to 2.5%.

10. The starting-up method of a roaster for treating chalcocite according to claim 1, characterized by, In S4, when the temperature of the fluidized layer is 750 to 770 ℃, the chalcocite is mainly oxidized, and the concentration of sulfur dioxide gas is 4.5 to 6%.