A dry desulfurization device and method for high-sulfur bauxite

Abstract

A dry desulfurization device and method for high-sulfur bauxite. The device includes a feeding unit, a drying and preheating unit, a suspension desulfurization furnace, a desulfurization reactor, a waste heat recovery unit, a combustion system, a purification unit and an emission unit. The method is as follows: After being weighed by the feeding unit, the high-sulfur bauxite powder enters the drying and preheating unit, and the preheated material enters the suspension desulfurization furnace, and the dusty waste gas enters the purification unit; The preheated material undergoes primary desulfurization in the suspension desulfurization furnace to form high-temperature material, and then gas-solid separation is carried out. The solid material enters the desulfurization reactor, and the hot waste gas is discharged into the drying and preheating unit; The solid material undergoes secondary desulfurization in the desulfurization reactor to form high-temperature clinker. The high-temperature clinker enters the waste heat recovery unit, and the reaction waste gas enters the suspension desulfurization furnace; The high-temperature clinker is cooled by the waste heat recovery unit, and the clinker is discharged into the clinker storage bin after cooling. The preheated air enters the suspension desulfurization furnace; The dusty waste gas enters the purification unit to complete desulfurization purification and dust removal. The solid dust is returned to the drying and preheating unit, and the purified waste gas is discharged into the atmosphere through the emission unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallurgy, and particularly relates to a dry desulfurization device and method for high-sulfur bauxite. Background Technique

[0002] In the light non-ferrous metallurgy industry, bauxite with a total sulfur content greater than 0.6% is customarily called high-sulfur bauxite. The proven bauxite reserves in China are about 2.3 billion tons, of which high-sulfur bauxite accounts for about 7.8%, and the calculated reserves are about 180 million tons. In these proven high-sulfur bauxites, sulfur mainly exists in the form of pyrite (FeS2), and mainly exists in the form of S 2- , SO3 2- , SO4 2- etc. during digestion, and the presence of sulfur will affect the digestion process or sintering process of alumina. Sulfur in the production process will combine with alkali to form sodium sulfate and crystallize out, and the precipitated sodium sulfate crystals will reduce the precipitation decomposition rate and the AH production capacity, and sulfides and thiosulfates will also exacerbate the corrosion of equipment and cause an increase in the concentration of soluble iron in the solution, ultimately resulting in unqualified quality of aluminum hydroxide. In addition, due to the easy adsorption of Al(OH) 4- , Na + ions and water by pyrite (FeS2) and sulfur pyrite, the properties of red mud will become worse. Therefore, how to solve the desulfurization problem of high-sulfur bauxite used for alumina production has become an urgent task to relieve the tense situation of ore resources for alumina production and reduce the external dependence on ore.

[0003] At present, the desulfurization of high-sulfur bauxite mostly focuses on wet desulfurization, and the reverse flotation process is adopted to float sulfur-containing minerals by adding collectors. However, wet desulfurization generally has the disadvantages of complex process, low alumina recovery rate, difficult tailings treatment, small hourly output at high sulfur content, and high desulfurization cost.

[0004] For this reason, Chinese Patent No. 201310330194.7 discloses a suspension preheating roasting desulfurization - rapid cooling process for high-sulfur bauxite. Although this process can meet the desulfurization requirements of high-sulfur bauxite, this process has the disadvantages of complex process, large floor area, large heat loss, high energy consumption, difficult to realize large-scale, relatively high roasting temperature, etc. At the same time, there is also the situation of under-roasting in the roasted clinker, and its adaptability to the composition change of high-sulfur bauxite is poor. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides a dry desulfurization device and method for high-sulfur bauxite, which have the characteristics of simple process, small floor area, small heat loss, low energy consumption, easy to realize large-scale, relatively low roasting temperature, etc., and the quality of roasted clinker is higher. The present invention realizes the rational cascade utilization of heat. The fuel burns directly in the suspension combustion furnace, reducing the setting of the path and the desulfurization reactor, improving the desulfurization reaction time and reaction temperature of the ore powder, so it is more energy-saving. The energy consumption can be reduced by 8.1% - 10.2% per ton of clinker. The present invention has stronger adaptability to the composition change of high-sulfur bauxite and can handle high-sulfur bauxite with a total sulfur content of 0.6% - 6%.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme: A dry desulfurization device for high-sulfur bauxite includes a feeding unit, a drying and preheating unit, a suspension desulfurization furnace, a desulfurization reactor, a waste heat recovery unit, a combustion system, a purification unit and an emission unit; the feeding end of the feeding unit is used to input high-sulfur bauxite powder, the discharging end of the feeding unit is connected to the feeding end of the drying and preheating unit through a first chute, the waste gas emission end of the drying and preheating unit is connected to the waste gas inlet end of the purification unit through a dust-containing waste gas emission pipe, the ash return end of the purification unit is connected to the feeding end of the drying and preheating unit through an ash return pipe, the waste gas emission end of the purification unit is connected to the waste gas inlet end of the emission unit through a purified waste gas emission pipe, and the waste gas emission end of the emission unit is used to output waste gas; the discharging end of the drying and preheating unit is connected to the feeding end of the suspension desulfurization furnace through a first discharge pipe, the hot waste gas emission end of the suspension desulfurization furnace is connected to the drying and preheating gas inlet end of the drying and preheating unit through a hot waste gas emission pipe, the discharging end of the suspension desulfurization furnace is connected to the feeding end of the desulfurization reactor through a second discharge pipe, the reaction waste gas emission end of the desulfurization reactor is connected to the reaction waste gas inlet end of the suspension desulfurization furnace through a reaction waste gas emission pipe, the discharging end of the desulfurization reactor is connected to the feeding end of the waste heat recovery unit through a second chute, the hot air emission end of the waste heat recovery unit is connected to the hot flue gas inlet end of the suspension desulfurization furnace through a hot air emission pipe, the discharging end of the waste heat recovery unit is used to output clinker, and the cold air inlet end of the waste heat recovery unit is used to input cold air; the high-temperature flue gas emission end of the combustion system outputs in three paths. The first path is directly connected to the hot flue gas inlet end of the suspension desulfurization furnace, the second path is connected to the drying and preheating gas inlet end of the drying and preheating unit through a first high-temperature flue gas emission pipe, and the third path is connected to the hot flue gas inlet end of the waste heat recovery unit through a second high-temperature flue gas emission pipe; the gas inlet end of the combustion system is used to input gas.

[0007] The feeding unit includes a buffer bin and a weighing scale. The feeding port of the buffer bin serves as the feeding end of the feeding unit. A material-saving valve is arranged at the discharging port of the buffer bin. The discharging port of the buffer bin is externally connected to a feeding chute through the weighing scale, and the discharging port of the feeding chute serves as the discharging end of the feeding unit.

[0008] The drying and preheating unit includes a dryer and a preheater, which are connected by a pipeline; the preheater adopts a single-stage structure or a multi-stage structure, and the multi-stage preheaters are connected by a pipeline; the feed inlet of the dryer serves as the feed end of the drying and preheating unit; when the preheater adopts a single-stage structure, the discharge outlet of the single-stage preheater serves as the discharge end of the drying and preheating unit; when the preheater adopts a multi-stage structure, the discharge outlet of the last-stage preheater serves as the discharge end of the drying and preheating unit.

[0009] The suspension desulfurization furnace includes a suspension reactor and a cyclone separator. The main structure of the suspension reactor is cylindrical, and the bottom of the suspension reactor is conical; the feed inlet of the suspension reactor serves as the feed end of the suspension desulfurization furnace, the discharge outlet at the top of the suspension reactor is connected to the feed inlet of the cyclone separator, and the discharge outlet of the cyclone separator serves as the discharge end of the suspension desulfurization furnace.

[0010] The desulfurization reactor includes a fluidized bed, a fluidizing air station and a Roots blower. The feed inlet of the fluidized bed serves as the feed end of the desulfurization reactor, and the discharge outlet of the fluidized bed serves as the discharge end of the desulfurization reactor; the fluidized bed is connected to the fluidizing air station and the fluidizing air station is connected to the Roots blower by pipelines; the fluidized bed adopts a multi-chamber fluidized bed, and each chamber of the fluidized bed is provided with an independent air chamber, and air distributors are arranged on the air chambers; air is used as the fluidizing air, which is provided by the fluidizing air station and the Roots blower.

[0011] The waste heat recovery unit includes a cyclone cooler and a fluidized bed cooler, which are connected by a pipeline; the cyclone cooler adopts a single-stage structure or a multi-stage structure, and the multi-stage cyclone coolers are connected by a pipeline; when the cyclone cooler adopts a single-stage structure, the feed inlet of the cyclone cooler serves as the feed end of the waste heat recovery unit; when the cyclone cooler adopts a multi-stage structure, the feed inlet of the first-stage cyclone cooler serves as the feed end of the waste heat recovery unit; the discharge outlet of the fluidized bed cooler serves as the discharge end of the waste heat recovery unit.

[0012] The combustion system includes a main combustion station, an auxiliary combustion station, a start-up combustion station and a drying combustion station. The fuels used in the main combustion station, the auxiliary combustion station and the start-up combustion station are solid fuels, liquid fuels or gaseous fuels.

[0013] The purification unit includes a gas desulfurization device, a dust collector, a chute, a centrifugal fan, a pneumatic conveying device, and a Roots blower. The gas desulfurization device, the dust collector, the chute, the centrifugal fan, the pneumatic conveying device, and the Roots blower are all connected by pipelines; the fluidizing air in the chute is provided by the centrifugal fan; the conveying air in the pneumatic conveying device is provided by the Roots blower; the dust collector uses a bag filter, a metal filter bag dust collector, an electrostatic precipitator, or an electrostatic bag precipitator; the pneumatic conveying device uses a pneumatic lift pump, a bin pump, or a vertical screw feeder.

[0014] The emission unit includes an induced draft fan, a damper, and a chimney. The exhaust port of the induced draft fan is connected to the chimney through the damper, and the smoke outlet of the chimney is connected to the atmosphere.

[0015] A dry desulfurization method for high-sulfur bauxite uses the dry desulfurization device for high-sulfur bauxite described above, and includes the following steps:

[0016] Step 1: Drying and preheating

[0017] Feed the high-sulfur bauxite powder into the buffer bin of the feeding unit. After being weighed by the weighing scale, it enters the drying and preheating unit. At this time, the ore powder will exchange heat with the hot waste gas discharged from the cyclone separator in the suspension desulfurization furnace. The ore powder is gradually preheated to 280°C - 400°C to form preheated material, and at the same time, the hot waste gas is cooled to 150°C - 200°C to form dust-containing waste gas. The preheated material directly enters the suspension desulfurization furnace, and the dust-containing waste gas directly enters the purification unit;

[0018] Step 2: Primary desulfurization

[0019] When the preheated material enters the suspension reactor of the suspension desulfurization furnace, the preheated material will be further heated to 400°C - 800°C by the high-temperature flue gas generated by the main combustion station in the combustion system to form high-temperature material. At this time, the oxygen content of the high-temperature flue gas in the suspension reactor is 3% - 8%, and the high-temperature material needs to stay in the suspension desulfurization furnace for 4s - 20s to make the desulfurization reaction rate reach 40% - 50%. After the primary desulfurization, the high-temperature material directly enters the cyclone separator of the suspension desulfurization furnace for gas-solid separation, and solid material and hot waste gas can be obtained. The solid material directly enters the desulfurization reactor, and the hot waste gas is directly discharged into the drying and preheating unit to participate in the preheating and drying of the ore powder;

[0020] Step 3: Secondary desulfurization

[0021] After the solid materials enter the fluidized bed of the desulfurization reactor, the unreacted pyrite minerals in the solid materials will further undergo desulfurization reactions with the oxygen in the fluidizing air. The reaction time is 5 minutes to 30 minutes until all the pyrite components in the solid materials complete the desulfurization reactions, thereby obtaining high-temperature clinker and reaction waste gas. The high-temperature clinker directly enters the waste heat recovery unit, and the reaction waste gas directly enters the suspended desulfurization furnace for recycling;

[0022] Step Four: Waste Heat Recovery

[0023] When the high-temperature clinker enters the cyclone cooler of the waste heat recovery unit, the high-temperature clinker will exchange heat with the cold air from the outside. The high-temperature clinker will be gradually cooled to below 100°C to form cooled clinker. At the same time, the cold air is gradually heated to 320°C - 500°C to form preheated air. The cooled clinker is discharged into the clinker storage bin for storage, and the preheated air directly enters the suspended desulfurization furnace for fuel combustion support of the combustion system;

[0024] Step Five: Waste Gas Purification

[0025] When the dust-containing waste gas enters the purification unit, desulfurization purification and dust removal are completed in sequence. The formed solid dust is directly returned to the drying and preheating unit for recovery. The formed purified waste gas is discharged into the atmosphere through the discharge unit, and the recovered SO2 is stored and used for sulfuric acid production.

[0026] Advantages of the present invention:

[0027] The dry desulfurization device and method for high-sulfur bauxite of the present invention have the characteristics of simple process, small floor area, small heat loss, low energy consumption, easy to realize large-scale, relatively low roasting temperature, etc., and the quality of the roasted clinker is higher. The present invention realizes the rational cascade utilization of heat. The fuel burns directly in the suspended combustion furnace, reducing the path and the setting of the desulfurization reactor, improving the desulfurization reaction time and reaction temperature of the ore powder, so it is more energy-saving. The energy consumption can be reduced by 8.1% - 10.2% per ton of clinker. The present invention has stronger adaptability to the composition change of high-sulfur bauxite and can process high-sulfur bauxite with a total sulfur content of 0.6% - 6%. Description of the Drawings

[0028] Figure 1 It is the structural schematic diagram of a dry desulfurization device for high-sulfur bauxite of the present invention;

[0029] In the figure, 1 is a feeding unit, 2 is a drying and preheating unit, 3 is a suspension desulfurization furnace, 4 is a desulfurization reactor, 5 is a waste heat recovery unit, 6 is a combustion system, 7 is a purification unit, 8 is an emission unit, 9 is a first chute, 10 is a dust-containing waste gas discharge pipe, 11 is a return ash pipe, 12 is a purified waste gas discharge pipe, 13 is a first discharge pipe, 14 is a hot waste gas discharge pipe, 15 is a second discharge pipe, 16 is a reaction waste gas discharge pipe, 17 is a second chute, 18 is a hot air discharge pipe, 19 is a first high-temperature flue gas discharge pipe, 20 is a second high-temperature flue gas discharge pipe, A is high-sulfur bauxite powder, B is waste gas, C is clinker, D is cold air, and E is fuel gas. Detailed implementation mode

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] As Figure 1 shown, a dry desulfurization device for high-sulfur bauxite includes a feeding unit 1, a drying and preheating unit 2, a suspension desulfurization furnace 3, a desulfurization reactor 4, a waste heat recovery unit 5, a combustion system 6, a purification unit 7 and an emission unit 8; the feeding end of the feeding unit 1 is used to input high-sulfur bauxite powder A, the discharging end of the feeding unit 1 is communicated with the feeding end of the drying and preheating unit 2 through a first chute 9, the waste gas discharging end of the drying and preheating unit 2 is communicated with the waste gas inlet end of the purification unit 7 through a dust-containing waste gas discharge pipe 10, the ash return end of the purification unit 7 is communicated with the feeding end of the drying and preheating unit 2 through an ash return pipe 11, the waste gas discharging end of the purification unit 7 is communicated with the waste gas inlet end of the emission unit 8 through a purified waste gas discharge pipe 12, and the waste gas discharging end of the emission unit 8 is used to output waste gas B; the discharging end of the drying and preheating unit 2 is communicated with the feeding end of the suspension desulfurization furnace 3 through a first discharge pipe 13, the hot waste gas discharging end of the suspension desulfurization furnace 3 is communicated with the drying and preheating gas inlet end of the drying and preheating unit 2 through a hot waste gas discharge pipe 14, the discharging end of the suspension desulfurization furnace 3 is communicated with the feeding end of the desulfurization reactor 4 through a second discharge pipe 15, the reaction waste gas discharging end of the desulfurization reactor 4 is communicated with the reaction waste gas inlet end of the suspension desulfurization furnace 3 through a reaction waste gas discharge pipe 16, the discharging end of the desulfurization reactor 4 is communicated with the feeding end of the waste heat recovery unit 5 through a second chute 17, the hot air discharging end of the waste heat recovery unit 5 is communicated with the hot flue gas inlet end of the suspension desulfurization furnace 3 through a hot air discharge pipe 18, the discharging end of the waste heat recovery unit 5 is used to output clinker C, and the cold air inlet end of the waste heat recovery unit 5 is used to input cold air D; the high-temperature flue gas discharging end of the combustion system 6 outputs in three paths, the first path is directly communicated with the hot flue gas inlet end of the suspension desulfurization furnace 3, the second path is communicated with the drying and preheating gas inlet end of the drying and preheating unit 2 through a first high-temperature flue gas discharge pipe 19, and the third path is communicated with the hot flue gas inlet end of the waste heat recovery unit 5 through a second high-temperature flue gas discharge pipe 20; the fuel gas inlet end of the combustion system 6 is used to input fuel gas E.

[0032] The feeding unit 1 includes a buffer bin and a weighing scale. The feed inlet of the buffer bin serves as the feed end of the feeding unit 1. A material-saving valve is provided at the discharge outlet of the buffer bin. The discharge outlet of the buffer bin is externally connected to a feed chute through the weighing scale, and the discharge outlet of the feed chute serves as the discharge end of the feeding unit 1. Specifically, the weighing scale can adopt an electronic metering feeder, a metering screw conveyor, an impact plate flowmeter or a rotor scale, and the material-saving valve can adopt a rod valve or a slide valve; when the moisture content of the high-sulfur bauxite powder A ≤ 2%, the rotor scale is preferably used for the weighing scale; when the moisture content of the high-sulfur bauxite powder A > 2%, the electronic metering feeder is preferably used for the weighing scale.

[0033] The drying and preheating unit 2 includes a dryer and a preheater, and the dryer and the preheater are connected by a pipeline; the preheater adopts a single-stage structure or a multi-stage structure, and the multi-stage preheaters are connected by a pipeline; the feed inlet of the dryer serves as the feed end of the drying and preheating unit 2; when the preheater adopts a single-stage structure, the discharge outlet of the single-stage preheater serves as the discharge end of the drying and preheating unit 2; when the preheater adopts a multi-stage structure, the discharge outlet of the last-stage preheater serves as the discharge end of the drying and preheating unit 2. Specifically, the dryer can adopt a Venturi dryer or a drying and dispersing machine, and the preheater can be set to a single-stage, two-stage or three-stage structure; when the moisture content of the high-sulfur bauxite powder A ≤ 8%, the Venturi dryer is preferably used for the dryer; when the moisture content of the high-sulfur bauxite powder A > 8%, the drying and dispersing machine is preferably used for the dryer.

[0034] The suspension desulfurization furnace 3 includes a suspension reactor and a cyclone separator. The main structure of the suspension reactor is cylindrical, and the bottom of the suspension reactor is conical; the feed inlet of the suspension reactor serves as the feed end of the suspension desulfurization furnace 3, the discharge outlet at the top of the suspension reactor is connected to the feed inlet of the cyclone separator, and the discharge outlet of the cyclone separator serves as the discharge end of the suspension desulfurization furnace 3.

[0035] The desulfurization reactor 4 includes a fluidized bed, a fluidization air station and a Roots blower. The feed inlet of the fluidized bed serves as the feed end of the desulfurization reactor 4, and the discharge outlet of the fluidized bed serves as the discharge end of the desulfurization reactor 4; the fluidized bed and the fluidization air station, and the fluidization air station and the Roots blower are all connected by pipelines; the fluidized bed adopts a multi-chamber fluidized bed, and independent air chambers are provided in each chamber of the fluidized bed, and air distributors are arranged on the air chambers; air is used as the fluidization air, and the fluidization air is provided by the fluidization air station and the Roots blower.

[0036] The waste heat recovery unit 5 includes a cyclone cooler and a fluidized bed cooler, which are connected by a pipeline; the cyclone cooler adopts a single-stage structure or a multi-stage structure, and the multi-stage cyclone coolers are connected by a pipeline; when the cyclone cooler adopts a single-stage structure, the feed inlet of the cyclone cooler serves as the feed end of the waste heat recovery unit 5; when the cyclone cooler adopts a multi-stage structure, the feed inlet of the first-stage cyclone cooler serves as the feed end of the waste heat recovery unit 5; the discharge outlet of the fluidized bed cooler serves as the discharge end of the waste heat recovery unit 5. Specifically, the fluidized bed cooler can be not configured according to the requirement of the final cooling temperature. When the cyclone cooler adopts a single-stage structure, the discharge outlet of the cyclone cooler serves as the discharge end of the waste heat recovery unit 5. When the cyclone cooler adopts a multi-stage structure, the discharge outlet of the last-stage cyclone cooler serves as the discharge end of the waste heat recovery unit 5; the cyclone cooler can be set to a single-stage, two-stage or three-stage structure.

[0037] The combustion system 6 includes a main combustion station, an auxiliary combustion station, a start-up combustion station and a drying combustion station. The fuels used in the main combustion station, the auxiliary combustion station and the start-up combustion station are solid fuels, liquid fuels or gaseous fuels. Specifically, whether the drying combustion station is configured can be determined according to the attached water condition of the material. Among them, the main combustion station is used to provide the heat required for the production of the desulfurization device, the auxiliary combustion station is used to ensure the safe ignition and operation of the desulfurization device, the start-up combustion station is used to bake the furnace lining of the newly built equipment with a furnace lining, and the drying combustion station is used to supplement the heat insufficient for the attached water of the dried ore powder filter cake.

[0038] The purification unit 7 includes a gas desulfurization device, a dust collector, a chute, a centrifugal fan, a pneumatic conveying device and a Roots blower, which are all connected by a pipeline; the fluidizing air in the chute is provided by the centrifugal fan; the conveying air in the pneumatic conveying device is provided by the Roots blower; the dust collector adopts a bag dust collector, a metal filter bag dust collector, an electrostatic precipitator or an electrostatic bag precipitator; the pneumatic conveying device adopts a pneumatic lifting pump, a bin pump or a vertical screw feeder. Specifically, a metal filter bag dust collector is preferably used, and a pneumatic lifting pump is preferably used for the pneumatic conveying device.

[0039] The emission unit 8 includes an induced draft fan, a damper and a chimney. The exhaust port of the induced draft fan is connected to the chimney through the damper, and the smoke exhaust port of the chimney is connected to the atmosphere.

[0040] In this embodiment, the equipment specifications of the feeding unit 1 are: the diameter of the buffer bin is φ3800mm, and the volume of the buffer bin is 85m 3, the weighing scale uses a rotor scale, and the measuring capacity of the rotor scale is 30 - 300 t / h. The equipment specifications of the drying and preheating unit 2 are as follows: the dryer uses a Venturi dryer, and the size specifications of the Venturi dryer are φ2470mm / φ3380mm. The preheater adopts a two-stage structure. The size specifications of the first-stage preheater are φ4290mm×φ9960mm, and the size specifications of the second-stage preheater are φ5330mm×φ11200mm. The equipment specifications of the suspension desulfurization furnace 3 are as follows: the size specifications of the suspension reactor are φ6400mm×19200mm, and the size specifications of the cyclone separator are φ6400mm×13800mm. The equipment specifications of the desulfurization reactor 4 are as follows: the size specifications of the fluidized bed are 2500mm×6700mm×3600mm, and the air supply capacity of the Roots blower is 117m 3 / min, and the air supply pressure is 39.4 Kpa. The equipment specifications of the waste heat recovery unit 5 are as follows: the cyclone cooler adopts a two-stage structure. The size specifications of the first-stage cyclone cooler are φ6500mm×14500mm, and the size specifications of the second-stage cyclone cooler are φ5600mm×12600mm. The size specifications of the fluidized bed cooler are 2400mm×2800mm×10300mm. The equipment specifications of the combustion system 6 are as follows: the fuel of the main combustion station uses gas, the gas flow rate is 60000m 3 / h, and the gas calorific value is 1450 kcal / m 3 . The equipment specifications of the purification unit 7 are as follows: the dust collector uses a bag filter, and the flue gas treatment capacity of the bag filter is 350000m 3 / h. The equipment specifications of the emission unit 8 are as follows: the air draft volume of the induced draft fan is 420000m 3 / h, and the air draft pressure is -9000 pa. The daily treatment capacity of the high-sulfur bauxite powder A of the desulfurization device is 3100 t / d - 6820 t / d. When the aluminum-silicon ratio of the high-sulfur bauxite powder A is 6.4 and the total sulfur content is 2% (where SO4 2- accounts for 0.08%, and the rest is sulfur in pyrite), the water content ≤ 15%, and the particle size distribution is: 100% < 0.3mm, 50% - 75% ≤ 0.074mm. The total sulfur content of the clinker after desulfurization of the ore powder is 0.2%. When the aluminum-silicon ratio of the high-sulfur bauxite powder A is 5.1 and the total sulfur content is 3.2% (where SO4 2- accounts for 0.07%, and the rest is sulfur in pyrite), the water content ≤ 8%, and the particle size distribution is: 100% < 0.3mm, 50% - 75% ≤ 0.074mm. The total sulfur content of the clinker after desulfurization of the ore powder is 0.32%.

[0041] A dry desulfurization method for high-sulfur bauxite uses the above-mentioned dry desulfurization device for high-sulfur bauxite, and includes the following steps:

[0042] Step 1: Drying and preheating

[0043] Feed high-sulfur bauxite powder A into the buffer bin of the feeding unit 1. After being weighed by the weighing scale, it enters the drying and preheating unit 2. At this time, the powder will exchange heat with the hot waste gas discharged from the cyclone separator in the suspension desulfurization furnace 3. The powder is preheated step by step to 280°C - 400°C to form preheated material, while the hot waste gas is cooled to 150°C - 200°C to form dust-containing waste gas. The preheated material directly enters the suspension desulfurization furnace 3, and the dust-containing waste gas directly enters the purification unit 7;

[0044] Step 2: Primary desulfurization

[0045] When the preheated material enters the suspension reactor of the suspension desulfurization furnace 3, the preheated material will be further heated to 400°C - 800°C by the high-temperature flue gas generated by the main combustion station in the combustion system 6 to form high-temperature material. At this time, the oxygen content of the high-temperature flue gas in the suspension reactor is 3% - 8%, and the high-temperature material needs to stay in the suspension desulfurization furnace 3 for 4s - 20s to make the desulfurization reaction rate reach 40% - 50%. After the primary desulfurization is completed, the high-temperature material directly enters the cyclone separator of the suspension desulfurization furnace 3 for gas-solid separation, and solid material and hot waste gas can be obtained. The solid material directly enters the desulfurization reactor 4, and the hot waste gas is directly discharged into the drying and preheating unit 2 to participate in the preheating and drying of the powder;

[0046] Step 3: Secondary desulfurization

[0047] When the solid material enters the fluidized bed of the desulfurization reactor 4, the unreacted pyrite minerals in the solid material will further react with the oxygen in the fluidizing air. The reaction time is 5min - 30min until all the pyrite components in the solid material complete the desulfurization reaction, and then high-temperature clinker and reaction waste gas are obtained. The high-temperature clinker directly enters the waste heat recovery unit 5, and the reaction waste gas directly enters the suspension desulfurization furnace 3 for recycling;

[0048] Step 4: Waste heat recovery

[0049] When the high-temperature clinker enters the cyclone cooler of the waste heat recovery unit 5, the high-temperature clinker will exchange heat with the cold air from the outside. The high-temperature clinker will be cooled step by step to below 100°C to form cooled clinker, while the cold air is heated step by step to 320°C - 500°C to form preheated air. The cooled clinker is discharged into the clinker storage bin for storage, and the preheated air directly enters the suspension desulfurization furnace 3 for fuel combustion support of the combustion system 6;

[0050] Step 5: Waste gas purification

[0051] After the dusty waste gas enters the purification unit 7, desulfurization purification and dust removal are completed in sequence. The formed solid dust is directly returned to the drying and preheating unit 2 for recovery. The purified waste gas formed is discharged into the atmosphere through the discharge unit 8, and the recovered SO2 is stored and used for acid making.

[0052] The solutions in the embodiments are not intended to limit the scope of patent protection of the present invention. All equivalent implementations or changes made without departing from the present invention are included in the patent scope of this case.

Claims

1. A dry desulfurization device for high-sulfur bauxite, characterized in that: It includes a feeding unit, a drying and preheating unit, a suspension desulfurization furnace, a desulfurization reactor, a waste heat recovery unit, a combustion system, a purification unit and an emission unit; The feeding end of the feeding unit is used to input high-sulfur bauxite powder. The discharging end of the feeding unit is connected to the feeding end of the drying and preheating unit through a first chute. The waste gas discharge end of the drying and preheating unit is connected to the waste gas inlet end of the purification unit through a dust-containing waste gas discharge pipe. The ash return end of the purification unit is connected to the feeding end of the drying and preheating unit through an ash return pipe. The waste gas discharge end of the purification unit is connected to the waste gas inlet end of the emission unit through a purified waste gas discharge pipe. The waste gas discharge end of the emission unit is used to output waste gas; The discharging end of the drying and preheating unit is connected to the feeding end of the suspension desulfurization furnace through a first discharge pipe. The hot waste gas discharge end of the suspension desulfurization furnace is connected to the drying and preheating gas inlet end of the drying and preheating unit through a hot waste gas discharge pipe. The discharging end of the suspension desulfurization furnace is connected to the feeding end of the desulfurization reactor through a second discharge pipe. The reaction waste gas discharge end of the desulfurization reactor is connected to the reaction waste gas inlet end of the suspension desulfurization furnace through a reaction waste gas discharge pipe. The discharging end of the desulfurization reactor is connected to the feeding end of the waste heat recovery unit through a second chute. The hot air discharge end of the waste heat recovery unit is connected to the hot flue gas inlet end of the suspension desulfurization furnace through a hot air discharge pipe. The discharging end of the waste heat recovery unit is used to output clinker. The cold air inlet end of the waste heat recovery unit is used to input cold air; The high-temperature flue gas discharge end of the combustion system outputs in three paths. The first path is directly connected to the hot flue gas inlet end of the suspension desulfurization furnace. The second path is connected to the drying and preheating gas inlet end of the drying and preheating unit through a first high-temperature flue gas discharge pipe. The third path is connected to the hot flue gas inlet end of the waste heat recovery unit through a second high-temperature flue gas discharge pipe; The gas inlet end of the combustion system is used to input gas; The feeding unit includes a buffer bin and a weighing scale. The feeding port of the buffer bin is used as the feeding end of the feeding unit. A material-saving valve is arranged at the discharging port of the buffer bin. The discharging port of the buffer bin is externally connected to a feeding chute through the weighing scale. The discharging port of the feeding chute is used as the discharging end of the feeding unit; The drying and preheating unit includes a dryer and a preheater, which are connected through a pipeline; The preheater adopts a single-stage structure or a multi-stage structure, and the multi-stage preheaters are connected through a pipeline; The feeding port of the dryer is used as the feeding end of the drying and preheating unit; When the preheater adopts a single-stage structure, the discharging port of the single-stage preheater is used as the discharging end of the drying and preheating unit; When the preheater adopts a multi-stage structure, the discharging port of the last-stage preheater is used as the discharging end of the drying and preheating unit; The suspension desulfurization furnace includes a suspension reactor and a cyclone separator. The main structure of the suspension reactor is cylindrical, and the bottom of the suspension reactor is conical; The feeding port of the suspension reactor is used as the feeding end of the suspension desulfurization furnace. The top discharging port of the suspension reactor is connected to the feeding port of the cyclone separator. The discharging port of the cyclone separator is used as the discharging end of the suspension desulfurization furnace; The desulfurization reactor includes a fluidized bed, a fluidizing air station and a Roots blower. The feed inlet of the fluidized bed serves as the feed end of the desulfurization reactor, and the discharge outlet of the fluidized bed serves as the discharge end of the desulfurization reactor; A pipeline is connected between the fluidized bed and the fluidizing air station, and between the fluidizing air station and the Roots blower; the fluidized bed adopts a multi-chamber fluidized bed, and an independent air chamber is arranged in each chamber of the fluidized bed, and air distributors are arranged on the air chamber; Air is used as the fluidizing air, and the fluidizing air is provided by the fluidizing air station and the Roots blower; The waste heat recovery unit includes a cyclone cooler and a fluidized bed cooler, and a pipeline is connected between the cyclone cooler and the fluidized bed cooler; The cyclone cooler adopts a single-stage structure or a multi-stage structure, and pipelines are connected between multi-stage cyclone coolers; When the cyclone cooler adopts a single-stage structure, the feed inlet of the cyclone cooler serves as the feed end of the waste heat recovery unit; When the cyclone cooler adopts a multi-stage structure, the feed inlet of the first-stage cyclone cooler serves as the feed end of the waste heat recovery unit; the discharge outlet of the fluidized bed cooler serves as the discharge end of the waste heat recovery unit; The combustion system includes a main combustion station, an auxiliary combustion station, a start-up combustion station and a drying combustion station. The fuels used in the main combustion station, the auxiliary combustion station and the start-up combustion station are solid fuels, liquid fuels or gaseous fuels; The purification unit includes a gas desulfurization device, a dust collector, a chute, a centrifugal fan, a pneumatic conveying device and a Roots blower. Pipelines are connected between the gas desulfurization device, the dust collector, the chute, the centrifugal fan, the pneumatic conveying device and the Roots blower; the fluidizing air in the chute is provided by the centrifugal fan; the conveying air in the pneumatic conveying device is provided by the Roots blower; The dust collector adopts a bag dust collector, a metal filter bag dust collector, an electrostatic precipitator or an electrostatic bag precipitator; the pneumatic conveying device adopts a pneumatic lifting pump, a bin pump or a vertical screw feeder; The discharge unit includes an induced draft fan, a damper and a chimney. The exhaust port of the induced draft fan is connected to the chimney through the damper, and the smoke outlet of the chimney is connected to the atmosphere; A dry desulfurization method for high-sulfur bauxite is characterized by comprising the following steps: Step 1: Drying and preheating. Feed the high-sulfur bauxite powder into the buffer bin of the feeding unit. After being weighed by the weighing scale, it enters the drying and preheating unit. At this time, the ore powder will exchange heat with the hot waste gas discharged from the cyclone separator in the suspension desulfurization furnace. The ore powder is gradually preheated to 280°C - 400°C to form preheated material, and at the same time, the hot waste gas is cooled to 150°C - 200°C to form dust-containing waste gas. The preheated material directly enters the suspension desulfurization furnace, and the dust-containing waste gas directly enters the purification unit; Step 2: Primary desulfurization When the preheated material enters the suspension reactor of the suspension desulfurization furnace, the preheated material will be further heated by the high-temperature flue gas generated by the main combustion station in the combustion system to 400°C - 800°C to form high-temperature material. At this time, the oxygen content of the high-temperature flue gas in the suspension reactor is 3% - 8%, and the high-temperature material needs to stay in the suspension desulfurization furnace for 4s - 20s to make the desulfurization reaction rate reach 40% - 50%. After the primary desulfurization is completed, the high-temperature material directly enters the cyclone separator of the suspension desulfurization furnace for gas-solid separation, and solid material and hot waste gas can be obtained. The solid material directly enters the desulfurization reactor, and the hot waste gas is directly discharged into the drying and preheating unit to participate in the preheating and drying of the ore powder; Step 3: Secondary desulfurization When the solid material enters the fluidized bed of the desulfurization reactor, the unreacted pyrite minerals in the solid material will further undergo a desulfurization reaction with the oxygen in the fluidizing air. The reaction time is 5min - 30min until all the pyrite components in the solid material complete the desulfurization reaction, and then high-temperature clinker and reaction waste gas are obtained. The high-temperature clinker directly enters the waste heat recovery unit, and the reaction waste gas directly enters the suspension desulfurization furnace for recycling; Step 4: Waste heat recovery When the high-temperature clinker enters the cyclone cooler of the waste heat recovery unit, the high-temperature clinker will exchange heat with the cold air from the outside. The high-temperature clinker will be gradually cooled to below 100°C to form cooled clinker, and at the same time, the cold air will be gradually heated to 320°C - 500°C to form preheated air. The cooled clinker is discharged into the clinker storage bin for storage, and the preheated air directly enters the suspension desulfurization furnace for fuel combustion support of the combustion system; Step 5: Exhaust gas purification When the dust-containing exhaust gas enters the purification unit, desulfurization purification and dust removal are completed in sequence. The formed solid dust is directly returned to the drying and preheating unit for recovery. The formed purified exhaust gas is discharged into the atmosphere through the discharge unit, and the recovered SO2 is stored for acid production.

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