A device and method for comprehensive utilization of high-sulfur bauxite base hydrogen reduction upgrading

Abstract

A device and method for comprehensive utilization of high-sulfur bauxite base hydrogen reduction upgrading, belonging to the technical field of comprehensive utilization of high-sulfur bauxite, comprising: (1) taking high-sulfur bauxite and base oxide as raw materials, and hydrogen as reducing agent; (2) high-sulfur bauxite, base oxide and hydrogen are used for base hydrogen reduction reaction in a poly-type stirred fluidized bed, iron in pyrite phase in bauxite is reduced to elemental iron powder, and sulfur is converted into base sulfide; (3) base sulfide is oxidized by its own waste heat to obtain base sulfate; (4) the obtained materials are separated by magnetic separation to recover elemental iron powder and bauxite concentrate; (5) the obtained concentrate enters the alumina production process to extract alumina, wherein the base sulfate in the concentrate does not affect the alumina production process.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization technology of high-sulfur bauxite, specifically relating to an apparatus and method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction and upgrading. Background Technology

[0002] my country has a massive alumina production, exceeding 80 million tons in 2022, accounting for more than 50% of the world's total output. However, my country suffers from a scarcity of bauxite resources, with low- to medium-grade bauxite accounting for 90% of its reserves. Currently, my country imports over 100 million tons of bauxite annually, representing more than 60% of its total bauxite needs. However, my country possesses 2 billion tons of high-iron, high-sulfur bauxite reserves awaiting development, twice the size of existing reserves. High-sulfur bauxite cannot be directly used in alumina production because sulfur causes increased alkali consumption, container scaling, deterioration of product quality, and equipment corrosion during the leaching process.

[0003] The current utilization process of high-sulfur bauxite mostly adopts the oxidative roasting method, which oxidizes the pyrite in high-sulfur bauxite to produce iron oxide and sulfur dioxide. Among them, the iron oxide enters the Bayer process and is discharged from the production system with the red mud, while the sulfur dioxide is absorbed by the flue gas and used as a raw material for the preparation of sulfuric acid.

[0004] Patent CN201910738682.9 discloses an apparatus and method for suspension roasting oxidation desulfurization of high-sulfur bauxite. (1) High-sulfur bauxite is crushed, dried, and placed in a silo; (2) An induced draft fan is turned on to create negative pressure in the system; (3) Natural gas and air are introduced into the burner, and after ignition, a high-temperature oxidizing gas is formed; (4) High-sulfur bauxite powder is fed into a primary cyclone separator, and the resulting primary solid material enters a suspension roasting furnace; (5) The primary solid material undergoes an oxidation roasting reaction, and the reacted material enters a secondary cyclone separator; (6) The secondary solid material is discharged through a discharge pipe. The method of this invention has a simple process flow, low overall energy consumption, high gas-solid mass and heat transfer efficiency, stable product properties, and high production efficiency.

[0005] Patent CN201210399209.0 discloses a method for activating high-sulfur bauxite using a low-temperature roasting desulfurization process. The method involves oxidative desulfurization roasting of bauxite with a sulfur content of 1-5 wt% to make it suitable as a raw material for Bayer process alumina production. The key feature is controlling the oxidative desulfurization temperature within the range of 500-600℃. Specifically, the ground ore powder is heated with hot air at 650-900℃ in a fluidized bed furnace or rotary kiln. After treatment, the sulfur content of the ore powder is reduced to below 0.5%, and the organic matter in the ore is completely oxidized and decomposed. Simultaneously, the low roasting temperature avoids the transformation of activated alumina, preventing excessive stability. When the roasted bauxite is used for Bayer process leaching, the leaching performance is improved, with an alumina leaching rate greater than 93%. For the SO2-containing tail gas generated by oxidative desulfurization, treatment with limestone suspension circulating spray desulfurization or red mud suspension spray desulfurization can reduce the SO2 content to 300 mg / m³. 3 The following meet the emission standards.

[0006] Two inherent drawbacks of the oxidative roasting process: (1) Iron resources in high-sulfur bauxite cannot be effectively utilized. During the oxidative roasting of high-sulfur bauxite, Fe in FeS2 is oxidized to Fe2O3, which enters the red mud during the bauxite leaching process. Currently, the cumulative stockpile of red mud in my country has exceeded 1.3 billion tons, and is increasing by about 100 million tons per year. The inability to utilize large amounts of alkaline red mud has become a global problem restricting the sustainable development of the alumina industry; (2) Low-concentration SO2 flue gas pollution and sulfuric acid treatment issues. Although the low-concentration SO2 flue gas generated during the roasting of high-sulfur bauxite is purified, a certain amount of SO2 is still emitted. In addition, for the production of sulfuric acid, its selling price is related to the transportation radius, and the storage of large amounts of sulfuric acid is also one of the problems that plague related production enterprises. Summary of the Invention

[0007] A device for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading includes a polymer-mixed fluidized bed, which consists of a discharge airlock system, an air inlet pipe, a furnace body, a side-mixing feeding device, a top mixing paddle, a flue gas passage, a flue gas outlet, and a motor. The side-stirring feeding device consists of a side-stirring shaft and a side-stirring paddle. The side-stirring shaft has a hollow internal structure with an inner diameter of 5-10 mm. Solid particles enter the fluidized bed from the bottom of the side-stirring shaft through the hollow pipe. The angle between the side-stirring shaft and the polymer-stirred fluidized bed furnace body is continuously adjustable within the range of 0° to 90°, and the stirring speed is continuously adjustable within the range of 0-500 rpm. The polymer-stirred fluidized bed is designed without a screen plate and is equipped with a discharge airlock system and an air inlet pipe at the bottom. After the material reaction is completed, it is discharged from the furnace body through the bottom discharge airlock. The top stirring shaft uses centrifugal force to separate fine particles back into the bed. The top stirring shaft has a hollow internal structure, allowing gas to enter the stirring shaft from the bottom and exit from the upper flue gas outlet through the flue gas channel inside the stirring shaft. The inner diameter of the stirring shaft is 1-5 mm to prevent small particles from escaping. The top stirring paddle is located at the bottom of the top stirring shaft to stir the material in the fluidized bed.

[0008] Compared with conventional fluidized beds, the polymer-type stirred fluidized bed of the present invention, equipped with a side stirring device, can reduce the large bubble rate by more than 60%, improve the heat transfer efficiency by more than 30%, and prevent the metal powder generated during reduction from sticking together; the dust rate of the top stirring device is reduced by less than 2%.

[0009] A method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading, implemented using the aforementioned apparatus, includes the following steps:

[0010] (1) Using high-sulfur bauxite and basic oxides as raw materials, and hydrogen as a reducing agent;

[0011] (2) High-sulfur bauxite, basic oxides, and hydrogen undergo a basic hydrogen reduction reaction using a polymeric stirred fluidized bed. Iron in the pyrite phase of bauxite is reduced to elemental iron powder, and sulfur is converted into basic sulfides.

[0012] (3) Basic sulfides are oxidized using their own residual heat to obtain basic sulfates;

[0013] (4) The reaction material is separated and recovered by magnetic separation to recover elemental iron powder and bauxite concentrate;

[0014] (5) The obtained concentrate is fed into the alumina production process to extract alumina, and the basic sulfates in the concentrate do not affect the alumina production process.

[0015] The high-sulfur bauxite mentioned in step (1) refers to bauxite with a sulfur content higher than 0.5 wt.%. The basic oxide is one or more of calcium-based oxides, sodium-based oxides, and potassium-based oxides.

[0016] The amount of alkaline oxide added in step (2) is calculated as 1 to 3 times the stoichiometric coefficient of alkaline metal and sulfur in the alkaline hydrogen reduction reaction of high-sulfur bauxite, and is equivalent to the amount of alkaline oxide added.

[0017] The reaction temperature for the base hydrogen reduction reaction in step (2) is 400-900℃, and the reaction time is 10-60 min.

[0018] In step (3), the basic sulfides in the solid slag discharged from the polymer-stirred fluidized bed are oxidized by their own residual heat to obtain basic sulfates, and the temperature of the solid slag is maintained at 20-300℃ for 10-120 min.

[0019] In step (4), the material obtained after the reaction is separated and the elemental iron powder is recovered by magnetic separation, with a magnetic separation intensity of 0.1 to 1T.

[0020] In step (5), the above-obtained concentrate enters the alumina production process to extract alumina. The basic sulfates in the concentrate do not affect the alumina production process. Excess calcium oxides can be used as dealkali removal raw materials in the bauxite calcification leaching process; excess sodium oxides can be used as leaching raw materials in the bauxite calcification leaching process; and excess potassium oxides can reduce the sodium alkali content in the leached red mud during the bauxite calcification leaching process.

[0021] The iron recovery rate in the high-sulfur bauxite is greater than 95%; the sulfur content in the concentrate obtained after magnetic separation and oxidation is higher than 95%. 2－ Content ≤0.1%.

[0022] This invention discloses a method for the comprehensive utilization of high-sulfur bauxite ore through alkaline hydrogen reduction upgrading. Taking calcium oxide as an example, pyrite and some iron oxide in high-sulfur bauxite ore are reduced to metallic iron powder and calcium sulfide. The metallic iron powder is recovered by magnetic separation, and the calcium sulfide is oxidized at low temperature to prepare calcium sulfate. The chemical reaction formulas for the reaction process include:

[0023] Base hydrogen reduction process:

[0024] FeS2+2CaO+2H2(g)=Fe+2CaS+2H2O(g)

[0025] Fe₂O₃ + 3H₂(g) = 2Fe + 3H₂O(g)

[0026] Low-temperature oxidation process:

[0027] CaS + 2O₂(g) = CaSO₄

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) Iron resources in high-sulfur bauxite are effectively utilized. Currently, most high-sulfur bauxite is processed using oxidative roasting, which converts pyrite in the bauxite into iron oxide, which then enters the Bayer process with the bauxite. This not only reduces the leaching effect of alumina in the bauxite but also results in the iron oxide being discharged with the red mud, thus failing to effectively utilize the iron resources. This invention employs a basic hydrogen reduction reaction to reduce the iron in pyrite into elemental iron powder, which is then separated by magnetic separation to obtain elemental iron powder, thereby improving the utilization value of high-sulfur bauxite.

[0030] (2) It eliminates the pollution from low-concentration SO2 flue gas and the problem of sulfuric acid treatment. This invention uses an alkaline hydrogen reduction reaction to convert sulfur in pyrite into calcium sulfide and enter the solid phase. The calcium sulfide is then oxidized to calcium sulfate at low temperature, thereby achieving the purpose of sulfur fixation. In the Bayer process, it will not affect the leaching process and solves the problem that high-sulfur bauxite cannot be used due to its high sulfur content.

[0031] (3) The present invention adopts a stirring fluidized bed, which reduces the large bubble rate by more than 60%, increases the heat transfer efficiency by more than 30%, and reduces the dust carrying rate by less than 2% compared with the conventional fluidized bed, thus preventing the metal powder generated during reduction from sticking together.

[0032] (4) Basic oxides serve as raw materials for basic hydrogen reduction and are also one of the raw materials for subsequent alumina extraction. Excess calcium-based compounds can be used as dealkali removal raw materials during the bauxite calcification and leaching process; excess sodium-based compounds can be used as leaching raw materials during the bauxite calcification and leaching process; and excess potassium-based compounds can reduce the sodium alkali content in the leached red mud during the bauxite calcification and leaching process. Furthermore, this invention adds excess basic oxides during hydrogen reduction to react with aluminum and silicon oxides in the bauxite, achieving sintering activation and thereby improving the alumina leaching efficiency in the subsequent Bayer process. Attached Figure Description

[0033] Figure 1 The process flow is a method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading.

[0034] Figure 2 Schematic diagram of a polymer-type stirred fluidized bed device;

[0035] Among them, 1-discharge airlock system, 2-air inlet pipe, 3-furnace body, 4-side stirring shaft, 5-side stirring paddle, 6-top stirring paddle, 7-flue gas passage, 8-flue gas outlet, 9-motor. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the embodiments.

[0037] The main components of the high-sulfur bauxite used in the embodiments of the present invention are Al2O3-63.85%, SiO2-15.84%, TiO2-2.93%, FeS2-4.64%, with the remainder being impurities.

[0038] Example 1

[0039] A device for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading includes a polymer-mixed fluidized bed, such as... Figure 2 As shown, it consists of a discharge airlock system 1, an air inlet pipe 2, a furnace body 3, a side stirring and feeding device, a top stirring paddle 6, a flue gas passage 7, a flue gas outlet 8, and a motor 9. The side-stirring feeding device consists of a side-stirring shaft 4 and a side-stirring paddle 5. The side-stirring shaft 4 has a hollow structure with an inner diameter of 10 mm. Solid particles enter the fluidized bed from the bottom of the side-stirring shaft through the hollow pipe of the side-stirring shaft 4. The angle between the side-stirring shaft 4 and the polymer-stirred fluidized bed furnace body 3 is continuously adjustable within the range of 0° to 90°, and the stirring speed is continuously adjustable within the range of 0 to 500 rpm. The polymer-stirred fluidized bed is designed without a screen plate and is equipped with a discharge airlock system 1 and an air inlet pipe 2 at the bottom. After the material reaction is completed, it is discharged from the furnace body through the bottom discharge airlock 1. The top stirring shaft uses centrifugal force to separate fine particles back into the bed. The top stirring shaft has a hollow structure, allowing gas to enter the stirring shaft from the bottom and be discharged from the upper flue gas outlet 8 through the flue gas channel 7 inside the stirring shaft. The inner diameter of the stirring shaft is 5 mm to prevent small particles from escaping. The top stirring paddle 6 is located at the bottom of the top stirring shaft and is used to stir the material in the fluidized bed.

[0040] A method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading is implemented using the aforementioned apparatus, such as... Figure 1 As shown, the specific operation steps are as follows:

[0041] (1) Mix high-sulfur bauxite with calcium oxide in a certain proportion. The amount of calcium oxide added is 1 times the stoichiometric coefficient of calcium and sulfur in the basic hydrogen reduction reaction of high-sulfur bauxite.

[0042] (2) High-sulfur bauxite, calcium oxide and hydrogen are carried out in a stirred fluidized bed to reduce iron in pyrite to elemental iron powder and sulfur to calcium sulfide. The basic hydrogen reduction process is carried out at a reaction temperature of 600℃ and a reaction time of 20min.

[0043] (3) Calcium sulfide in the solid slag discharged from the polymer-stirred fluidized bed is oxidized using its own residual heat to obtain calcium sulfate; the oxidation temperature is 20℃, the oxidation time is 60min, and after the reaction is completed, the calcium sulfate in the solid slag is... 2－ The content is 0.1%;

[0044] (4) The material obtained after the reaction is separated and the elemental iron is recovered by magnetic separation. The magnetic field strength is 0.1T to obtain reduced iron powder. The recovery rate of iron in high-sulfur bauxite is 96%.

[0045] (5) The concentrate can be directly used in the Bayer process to extract alumina, and calcium sulfate is carried out of the reaction system with the red mud.

[0046] Example 2

[0047] A method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading, implemented using the apparatus described in Example 1, with the specific operation steps as follows:

[0048] (1) Mix high-sulfur bauxite with sodium oxide in a certain proportion, and add calcium oxide according to the stoichiometric coefficient of sodium and sulfur in the basic hydrogen reduction reaction of high-sulfur bauxite.

[0049] (2) High-sulfur bauxite, sodium oxide and hydrogen are carried out in a stirred fluidized bed to reduce iron in pyrite to elemental iron powder and sulfur to sodium sulfide. The basic hydrogen reduction process is carried out at a reaction temperature of 700℃ and a reaction time of 10min.

[0050] (3) Sodium sulfide in the solid slag discharged from the polymer-stirred fluidized bed is oxidized to sodium sulfate using its own residual heat. The solid slag temperature is 60℃, the oxidation time is 20min, and after the reaction is completed, the sodium sulfate in the concentrate obtained after magnetic separation is... 2－ Content ≤0.1%;

[0051] (4) The material obtained after the reaction is subjected to magnetic separation to recover elemental iron. The magnetic field strength is 1T to obtain reduced iron powder. The iron recovery rate in the high-sulfur bauxite is calculated to be 97%.

[0052] (5) The concentrate can be directly used in the Bayer process to extract alumina, and sodium sulfate is carried out of the reaction system with the red mud.

[0053] Example 3

[0054] A method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading, implemented using the apparatus described in Example 1, with the specific operation steps as follows:

[0055] (1) Mix high-sulfur bauxite with potassium oxide in a certain proportion, wherein the amount of potassium oxide added is 1 times the stoichiometric coefficient of potassium and sulfur in the basic hydrogen reduction reaction of high-sulfur bauxite.

[0056] (2) High-sulfur bauxite, potassium oxide and hydrogen are carried out in a stirred fluidized bed to reduce iron in pyrite to elemental iron powder and sulfur to potassium sulfide. The basic hydrogen reduction process is carried out at a reaction temperature of 600℃ and a reaction time of 20min.

[0057] (3) Potassium sulfide in the solid slag discharged from the polymer-stirred fluidized bed is oxidized to potassium sulfate using its own residual heat. The solid slag temperature is 100℃, the oxidation time is 50 min, and after the reaction is completed, the potassium sulfate in the concentrate obtained after magnetic separation is... 2－ The content is 0.08%;

[0058] (4) The material obtained after the reaction is subjected to magnetic separation to recover elemental iron. The magnetic field strength is 0.5T to obtain reduced iron powder. The iron recovery rate in the high-sulfur bauxite is calculated to be 96%.

[0059] (5) The concentrate can be directly used in the Bayer process to extract alumina, and potassium sulfate is carried out of the reaction system with the red mud.

[0060] Example 4

[0061] A method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading, implemented using the apparatus described in Example 1, with the specific operation steps as follows:

[0062] (1) Mix high-sulfur bauxite with sodium oxide in a certain proportion, wherein the amount of calcium oxide added is twice the stoichiometric coefficient of sodium and sulfur in the basic hydrogen reduction reaction of high-sulfur bauxite.

[0063] (2) High-sulfur bauxite, sodium oxide and hydrogen are carried out in a stirred fluidized bed to reduce iron in pyrite to elemental iron powder and sulfur to sodium sulfide. The basic hydrogen reduction process is carried out at a reaction temperature of 900℃ and a reaction time of 30min.

[0064] (3) Sodium sulfide in the solid slag discharged from the polymer-stirred fluidized bed is oxidized by its own residual heat to obtain sodium sulfate. The oxidation temperature is 300℃ and the oxidation time is 15min. After the reaction is completed, the sodium sulfate in the concentrate obtained after magnetic separation is reduced. 2－ The content is 0.08%.

[0065] (4) The material obtained after the reaction was subjected to magnetic separation to recover elemental iron. The magnetic field strength was 0.6T, and reduced iron powder was obtained. The iron recovery rate in the high-sulfur bauxite was calculated to be 97%.

[0066] (5) The concentrate can be directly used in the Bayer process to extract alumina, and sodium sulfate is carried out of the reaction system with the red mud.

[0067] Example 5

[0068] A method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading, implemented using the apparatus described in Example 1, with the specific operation steps as follows:

[0069] (1) Mix high-sulfur bauxite with potassium oxide in a certain proportion, wherein the amount of potassium oxide added is three times the stoichiometric coefficient of potassium and sulfur in the basic hydrogen reduction reaction of high-sulfur bauxite.

[0070] (2) High-sulfur bauxite, potassium oxide and hydrogen are carried out in a stirred fluidized bed to reduce iron in pyrite to elemental iron powder and sulfur to potassium sulfide. The basic hydrogen reduction process is carried out at a reaction temperature of 400℃ and a reaction time of 50min.

[0071] (3) Potassium sulfide in the solid slag discharged from the polymer-stirred fluidized bed is oxidized to potassium sulfate using its own residual heat. The solid slag temperature is 240℃, the oxidation time is 60min, and after the reaction is completed, the potassium sulfate in the concentrate obtained after magnetic separation is... 2－ The content is 0.09%;

[0072] (4) The material obtained after the reaction is subjected to magnetic separation to recover elemental iron. The magnetic field strength is 0.8T to obtain reduced iron powder. The iron recovery rate in the high-sulfur bauxite is calculated to be 95%.

[0073] (5) The concentrate can be directly used in the Bayer process to extract alumina, and calcium sulfate is carried out of the reaction system with the red mud.

Claims

1. A device for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading, characterized in that, The system includes a polymer-mixed fluidized bed, which consists of a discharge airlock system (1), an air inlet pipe (2), a furnace body (3), a side-stirring feeding device, a top stirring paddle (6), a flue gas passage (7), a flue gas outlet (8), and a motor (9). The side-stirring feeding device consists of a side stirring shaft (4) and a side stirring paddle (5). The side stirring shaft (4) has a hollow internal structure, and solid particles enter the fluidized bed from the bottom of the stirring shaft through the hollow pipe of the side stirring shaft (4). The angle between the side stirring shaft (4) and the polymer-mixed fluidized bed furnace body (3) is continuously adjustable within the range of 0° to 90°. The stirring speed is continuously adjustable within the range of 0 to 500 rpm; the polymer-type stirred fluidized bed is designed without a screen plate, and the bottom is equipped with a discharge airlock system (1) and an air inlet pipe (2). After the material reaction is completed, it is discharged from the furnace body through the bottom discharge airlock; the top stirring shaft uses centrifugal force to separate fine particles back into the bed. The interior of the top stirring shaft is a hollow structure, allowing gas to enter the interior of the stirring shaft from the bottom and be discharged from the upper flue gas outlet (8) through the flue gas channel (7) in the stirring shaft to prevent small particles from escaping. The top stirring paddle (6) is set at the bottom of the top stirring shaft to stir the material in the fluidized bed.

2. The apparatus for comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction and upgrading according to claim 1, characterized in that, The inner diameter of the side stirring shaft (4) is 5-10 mm; the inner diameter of the top stirring shaft is 1-5 mm.

3. A method for the comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading, implemented using the apparatus described in claim 1, characterized in that... Includes the following steps: (1) Using high-sulfur bauxite and basic oxides as raw materials, and hydrogen as a reducing agent; (2) High-sulfur bauxite, basic oxides, and hydrogen undergo a basic hydrogen reduction reaction using a polymeric stirred fluidized bed. Iron in the pyrite phase of bauxite is reduced to elemental iron powder, and sulfur is converted into basic sulfides. (3) Basic sulfides are oxidized using their own residual heat to obtain basic sulfates; (4) The reaction material is separated and recovered by magnetic separation to recover elemental iron powder and bauxite concentrate; (5) The obtained concentrate is fed into the alumina production process to extract alumina, and the basic sulfates in the concentrate do not affect the alumina production process.

4. The method for comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading according to claim 3, characterized in that, The high-sulfur bauxite mentioned in step (1) refers to bauxite with a sulfur content higher than 0.5 wt.%; the basic oxide is one or more of calcium oxide, sodium oxide, and potassium oxide.

5. The method for comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading according to claim 3, characterized in that, The amount of alkaline oxide added in step (2) is calculated as 1 to 3 times the stoichiometric coefficient of alkaline metal and sulfur in the alkaline hydrogen reduction reaction of high-sulfur bauxite, and is equivalent to the amount of alkaline oxide added.

6. The method for comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading according to claim 3, characterized in that, The reaction temperature for the base hydrogen reduction reaction in step (2) is 400-900℃, and the reaction time is 10-60 min.

7. The method for comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading according to claim 3, characterized in that, In step (3), the basic sulfides in the solid slag discharged from the polymer-stirred fluidized bed are oxidized by their own residual heat to obtain basic sulfates, and the temperature of the solid slag is maintained at 20-300℃ for 10-120 min.

8. The method for comprehensive utilization of high-sulfur bauxite through alkaline hydrogen reduction upgrading according to claim 3, characterized in that, In step (4), the material obtained after the reaction is separated and the elemental iron powder is recovered by magnetic separation, with a magnetic separation intensity of 0.1 to 1T.

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