Method for roasting and activating high-iron bauxite

Abstract

The invention relates to the field of high-efficiency utilization of high-iron bauxite, in particular to a high-iron bauxite roasting and activating treatment method which comprises the following steps: adding an activating agent into high-iron bauxite, mixing, and grinding to prepare pellets; activating the pellets in a closed reactor to obtain a magnetic iron-rich phase and activated roasted ore; the activated roasted ore is subjected to solid-liquid separation through a calcification transformation high-temperature dissolution technology, and a sodium aluminate solution and calcification transformation red mud are obtained. According to the method, the removal rate of the treated organic matter is larger than 90%, the non-magnetic iron-rich phase is converted into the magnetic iron-rich phase after activation treatment, the iron recovery rate is larger than 50% after heavy magnetic separation, the yield is larger than 35%, the TFe of the iron concentrate powder reaches 56% or above, and the red mud per ton of aluminum oxide is reduced by more than 35% from an aluminum oxide production source; by adopting a calcification transformation high-temperature dissolution technology, the dissolution rate is increased by 3-5%, the alkali content in the red mud is less than 1%, and red mud source reduction and red mud harmless treatment for producing aluminum oxide from high-iron bauxite can be realized.

Description

Technical Field

[0001] The present invention relates to the field of efficient utilization of high-iron bauxite, and in particular to a method for roasting and activating high-iron bauxite. Background Art

[0002] Imported bauxite has a high iron oxide content. When using the Bayer process to process high-iron bauxite, the higher iron content in the mineral will also lead to an increase in the amount of red mud produced during the production process. Since the equilibrium solid phase of the Bayer process is hydrated sodium aluminosilicate, even if the aluminum-silicon ratio of the mineral is very high, the sodium content in the red mud is difficult to meet the requirements of industries such as cement, which also limits the effective utilization of iron in the red mud.

[0003] Publication No. CN202411262251.7 specifically relates to a method for extracting iron from high-iron bauxite using biomass as a clean reducing agent. The method comprises the following steps: (1) uniformly mixing high-iron bauxite and biomass, heating to 600-700°C under oxygen-free conditions, and roasting to obtain a roasted material; (2) dissolving the roasted material obtained in step (1) using the Bayer process to obtain solid slag and a dissolving liquid; (3) magnetically separating the solid slag obtained in step (2) to obtain an iron concentrate. The method of the present invention involves uniformly mixing high-iron bauxite and biomass, followed by high-temperature reduction under inert atmosphere conditions. During this process, hematite is reduced to magnetite. Subsequently, through dissolution and magnetic separation, iron concentrate and red mud with extremely low iron and aluminum content are obtained. The iron concentrate can be used as a raw material for ironmaking. This achieves the comprehensive utilization of high-iron bauxite and biomass, solving the problem of utilizing iron resources in high-iron bauxite. However, this patent only considers the magnetic roasting of high-iron bauxite and uses the roasted bauxite in the Bayer process, without considering the activity of the bauxite. At the same time, the sodium content in the red mud after dissolution by the Bayer process is relatively high, and the selected iron concentrate contains a certain amount of sodium, which leads to a lower grade of the iron concentrate. At the same time, the utilization of the red mud after iron selection is not considered.

[0004] Publication No. CN202411049054.7 discloses a method for recovering iron and aluminum from high-iron bauxite by direct reduction, electric furnace smelting, and magnetic separation, belonging to the field of ore smelting technology. The method comprises the following steps: (1) crushing and grinding the high-iron bauxite and reducing coal to uniformly mix; (2) directly reducing the ore in a tubular furnace to obtain reduced ore; (3) performing weak magnetic separation on the reduced ore to separate aluminum concentrate and iron concentrate, and then spreading a layer of reducing coal powder on the surface of the iron concentrate; (4) performing strong magnetic separation on the aluminum concentrate to separate high-quality bauxite and ferroaluminum spinel; (5) uniformly mixing the high-quality bauxite and the iron concentrate covered with reducing coal powder and placing them in an electric arc furnace for smelting. After smelting, the copper pot is removed and cooled; (6) after air cooling, crushing and magnetic separation are performed to obtain ferrosilicon alloy and high-purity alumina. The method of the present invention can effectively recover the iron and aluminum in high-iron bauxite. However, this method does not take into account the dissolution performance of alumina, and the smelting method has high energy consumption and cost, and the product is not competitive enough.

[0005] Publication No. CN202410890274.6 discloses a method for the graded utilization of high-iron bauxite. The method involves grinding the bauxite slurry to control the particle size and content. The fine bauxite slurry is then graded for gravity separation of coarse and fine slurries. A magnetic separator separates the iron ore to produce a magnetic concentrate and tailings. After the coarse gravity separation slurry is mixed with the magnetic concentrate, the main phases are aluminum and iron, along with small amounts of titanium and silicon. Based on the existing Bayer process, the high-iron bauxite is graded into a high-aluminum, high-iron, low-silicon, low-titanium slurry and a low-aluminum, low-iron, high-silicon, high-titanium slurry. The high-temperature Bayer process in the former facilitates the full dissolution of insoluble aluminum-containing minerals, increasing the alumina dissolution rate while producing less red mud. This allows for the production of red mud with a high iron content, making it easier for the steel industry to utilize. The low-temperature Bayer process in the latter helps reduce the reaction between silicon and titanium minerals, reducing alkali consumption. However, the investment in high-iron bauxite particle size classification equipment is high, and the low-temperature dissolution efficiency is relatively low.

[0006] The current technological system has not yet broken through the difficulties of coordinated optimization of economy, product quality and solid waste utilization, especially the content of sodium aluminum silicon phase (Na2O·Al2O3·2SiO2) in red mud is difficult to stably reduce to below 1%. Coupled with the high cost of iron and aluminum recovery, it seriously restricts the efficient and large-scale utilization of high-iron bauxite. It is urgent to develop low-cost and large-scale high-iron bauxite utilization technology. Summary of the Invention

[0007] (1) Technical issues to be resolved

[0008] Given that in the existing technology, it is difficult to stably reduce the sodium, aluminum and silicon phase content of recovered red mud to below 1%, coupled with the high cost of iron and aluminum recovery, this is a technical problem that seriously restricts the efficient and large-scale utilization of high-iron bauxite.

[0009] (2) Technical solution

[0010] To this end, the present invention provides a method for roasting and activating high-iron bauxite, comprising:

[0011] Step 1: Add an activator to the high-iron bauxite, mix it, grind it, and make it into pellets;

[0012] Step 2: Activating the pellets in a closed reactor to obtain a magnetic iron-rich phase and activated roasted ore;

[0013] Step 3: The activated roasted ore is subjected to calcification transformation high temperature dissolution technology to separate the solid and liquid products into sodium aluminate solution and calcification transformation red mud.

[0014] Further, the activator is a mixture of a carbonaceous material and an alkaline compound;

[0015] and / or, a mixture of hydrogen and a basic compound.

[0016] Furthermore, the carbonaceous material is at least one of coal, coke, coke dust or biomass.

[0017] Furthermore, the basic compound is at least one of an alkali metal, an alkaline earth metal oxide, a hydroxide or a carbonate.

[0018] Furthermore, in step 2, the activation temperature is controlled to be 500° C.-750° C., and the activation time is 5-30 minutes.

[0019] Furthermore, when a mixture of carbonaceous material and alkaline compound is used as an activator, the pellet activation reactor adopts at least one of a packed bed, a moving bed, a fluidized bed or a rotary kiln, and the reactor is equipped with an air lock for feeding and discharging materials.

[0020] Furthermore, when hydrogen and carbonaceous material are used as activating agents, the gas activation reactor adopts at least one of a fluidized bed, a transport bed or a multi-stage cyclone heat exchanger.

[0021] Furthermore, the magnetic iron-rich phase is subjected to gravity magnetic separation.

[0022] Furthermore, the calcification transformation high temperature dissolution technology is at least one of the calcification carbonization high temperature dissolution technology, the calcification biomass high temperature dissolution technology or the calcification potash high temperature dissolution technology.

[0023] Furthermore, the dissolution temperature of the calcification transformation high-temperature dissolution technology is greater than 270°C.

[0024] (3) Beneficial effects:

[0025] The beneficial effects of the present invention are as follows: the present invention mentions a method for roasting and activating high-iron bauxite, comprising: adding an activator to the high-iron bauxite, mixing and grinding the mixture to form pellets; activating the pellets in a closed reactor to obtain a magnetic iron-rich phase and activated roasted ore; subjecting the activated roasted ore to a calcification transformation high-temperature dissolution technology, and separating the product into solid and liquid to obtain a sodium aluminate solution and a calcification transformation red mud.

[0026] The present invention discloses a method for roasting and activating high-iron bauxite. The method uses imported high-iron gibbsite ore, controls the activation temperature at 500°C-750°C, and the activation time at 5-30 minutes. The activator is a mixture of a carbonaceous substance and an alkaline compound. After activation, the organic matter in the bauxite decomposes, with an organic matter removal rate exceeding 90%. The non-magnetic iron-rich phase is converted into a magnetic iron-rich phase after activation. After heavy magnetic separation, the iron recovery rate exceeds 50%, the yield exceeds 35%, and the iron concentrate TFe reaches over 56%. This reduces red mud production at the source of alumina by more than 35%. The activated roasted ore utilizes a calcification transformation high-temperature dissolution technology, which increases the dissolution rate by 3%-5%, reduces the alkali content in the red mud to less than 1%, and enables its use in building materials, among other applications. This technology can achieve both source reduction and harmless treatment of red mud in alumina production from high-iron bauxite. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a process flow chart of a method for roasting and activating high-iron bauxite mentioned in this application;

[0028] Figure 2 This is another process flow chart of the method for roasting and activating high-iron bauxite mentioned in this application. DETAILED DESCRIPTION

[0029] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0030] When amount, concentration or other value or parameter are represented with range, preferred range or the range that a series of upper preferred value and lower preferred value limit are expressed, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, and no matter whether this scope is disclosed separately.For example, when disclosing scope " 1-5 ", described scope should be interpreted as including scope " 1-4 ", " 1-3 ", " 1-2 ", " 1-2 and 4-5 ", " 1-3 and 5 " etc.When numerical range is described in this article, unless otherwise stated, otherwise this scope is intended to include its end value and all integers and fractions within this range.

[0031] In these embodiments, unless otherwise indicated, the parts and percentages are all measured by mass. "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1g, 3.527g, etc. If we say that the mass parts of component A are a parts and the mass parts of component B are b parts, then it means that the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiplication factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0032] refer to Figure 1 and Figure 2 The present invention mentions a method for roasting and activating high-iron bauxite, comprising:

[0033] Step 1: Add an activator to the high-iron bauxite, mix it, grind it, and make it into pellets;

[0034] It should be noted that the high-iron bauxite mentioned in this application is selected from high-iron gibbsite ore imported from abroad, with an activation temperature of 500°C-750°C and an activation time of 5-30 minutes.

[0035] It should be noted that the high iron bauxite is fully contacted with the activator during the mixing and grinding process to ensure that in the subsequent activation treatment, the activator can evenly act on all parts of the bauxite, making the reaction more complete and uniform.

[0036] It should be noted that pelletizing can improve the physical properties of the material, increase the bulk density and strength of the material, facilitate processing in the reactor, reduce the loss and flying of the material during transportation and reaction, and also facilitate the control of the reaction.

[0037] It should be noted that the activator is a mixture of a carbonaceous material and an alkaline compound or a mixture of hydrogen and an alkaline compound. The carbonaceous material is at least one of coal, coke, coke powder or biomass. The carbonaceous material can act as a reducing agent in the subsequent activation process to promote the conversion of the non-magnetic iron-rich phase into a magnetic iron-rich phase; further, the basic compound is at least one of an alkali metal, an alkaline earth metal oxide, a hydroxide or a carbonate. The alkaline compound can activate the bauxite, avoiding the problem of deactivation of high iron in the bauxite caused by traditional roasting and reducing the efficiency of bauxite dissolution. When hydrogen is used as an activator, it has a strong reducing property and can more effectively promote the conversion of the iron phase.

[0038] Step 2: Activate the pellets in a closed reactor to obtain a magnetic iron-rich phase and activated roasted ore.

[0039] It should be noted that at an activation temperature of 500°C-750°C and an activation time of 5-30 minutes, the organic matter in the bauxite will decompose, with a decomposition rate exceeding 90%. This helps to reduce the impact of organic matter on product quality and the environment during subsequent processing.

[0040] It should be noted that the activation treatment converts the non-magnetic iron-rich phase into a magnetic iron-rich phase, which is then subjected to heavy magnetic separation. This effectively separates the magnetic iron-rich phase from other substances, helping to improve iron recovery and the grade of iron ore concentrate. The iron recovery rate is >50%, and the TFe content of the iron ore concentrate reaches over 56%. This not only improves the recycling rate of iron resources, but also produces high-grade iron ore concentrate that can be used as a raw material for ironmaking, effectively utilizing the iron resources in high-iron bauxite. Furthermore, after magnetic separation, the amount of raw material entering the alumina production system is reduced, reducing red mud at the source of alumina production by more than 35% per ton of alumina, achieving source reduction in red mud emissions.

[0041] Among them, the alkaline compounds in the activator activate bauxite during the activation process, increase the activity of bauxite, create favorable conditions for the subsequent high-temperature dissolution process, and help to increase the dissolution rate of alumina.

[0042] When a mixture of carbonaceous material and alkaline compound is used as an activator, a packed bed, moving bed, fluidized bed or rotary kiln is used, and an air lock for inlet and outlet is provided to ensure that the reaction is carried out in a relatively stable environment, reduce heat and gas loss, and improve reaction efficiency.

[0043] When hydrogen and alkaline compounds are used as activators, a fluidized bed, a conveying bed or a multi-stage cyclone heat exchanger is used to enable the hydrogen to fully contact the pellets, thereby improving the mass transfer and heat transfer efficiency of the reaction and promoting the reaction.

[0044] Step 3: The activated roasted ore is subjected to calcification transformation high temperature dissolution technology to separate the solid and liquid products into sodium aluminate solution and calcification transformation red mud.

[0045] The activated roasted ore is subjected to calcification transformation high temperature dissolution technology, and the product solid-liquid separation is carried out to obtain sodium aluminate solution and calcification transformation red mud.

[0046] It should be noted that the dissolution temperature is greater than 270°C, and the dissolution rate exceeds the theoretical dissolution rate of the Bayer process. Because the activated roasted ore is more active after activation, alumina can dissolve more fully into the solution under high temperature and specific dissolution conditions, thereby improving the extraction efficiency of alumina. Through calcification transformation and high-temperature dissolution technology, the alkali content in the red mud is less than 1%, and the red mud aluminum-silicon ratio is less than 1%. This improves the properties of the red mud, allowing it to be used in building materials, soil remediation, or as a soil conditioner. This achieves comprehensive utilization of red mud, reduces solid waste emissions, and reduces environmental impact.

[0047] When using the calcification carbonization high-temperature dissolution technology, the alkali content in red mud can be effectively reduced, the dissolution rate is greater than the theoretical dissolution rate of the Bayer process, and the red mud aluminum-silicon ratio is less than 1%, making the red mud more suitable for use in the building materials and other industries.

[0048] When using the calcified biomass high-temperature dissolution technology, not only can the dissolution rate of alumina be improved, but the red mud can also be further magnetically separated, increasing iron recovery by 30%, thus realizing the comprehensive recycling of iron and aluminum.

[0049] By using the high-temperature dissolution technology of calcified potash method, red mud can be transformed into silicon-potassium fertilizer and mineral compound fertilizer, thus realizing high added value utilization of red mud and improving the comprehensive utilization rate of resources.

[0050] After activation, organic matter in the bauxite decomposes, achieving an organic matter removal rate exceeding 90%. The non-magnetic iron-rich phase is converted to a magnetic iron-rich phase after activation. After heavy magnetic separation, the iron recovery rate exceeds 50%, the yield exceeds 35%, and the iron concentrate TFe reaches over 56%. This reduces red mud at the source of alumina production by more than 35%. The activated roasted ore utilizes calcification transformation and high-temperature dissolution technology, which increases the dissolution rate by 3% to 5%, reduces the alkali content in the red mud to less than 1%, and can be used in building materials, among other applications. This technology can achieve both source reduction and harmless treatment of red mud in alumina production from high-iron bauxite.

[0051] To better understand the technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0052] The Guinea high iron bauxite used in the embodiments of the present invention, the alkaline compound is one of the alkali metal or alkaline earth metal compounds such as calcium oxide, calcium carbonate, sodium carbonate, potassium carbonate, etc., and other alkali metal or alkaline earth metal compounds can be used as alkaline oxide raw materials.

[0053] Example 1

[0054] The alkaline compound used in this embodiment is calcium oxide. High-iron bauxite, calcium oxide, and coal are fully mixed and ground to form pellets, which are then activated in a packed bed moving bed at a temperature of 500°C for 5 minutes. After activation, the organic matter in the bauxite decomposes, with an organic matter removal rate of 90%. After activation, the non-magnetic iron-rich phase is converted into a magnetic iron-rich phase with a conversion rate of 90%. After heavy magnetic separation, the iron recovery rate is 50%, the yield is 35%, and the iron concentrate TFe content is 56%. The activated roasted ore uses calcification transformation high-temperature dissolution technology with a dissolution temperature of 275°C, which increases the dissolution rate by 3%. The alkali content in the red mud is 0.8%, and the resulting red mud can be used for building materials, soil remediation, or soil conditioners.

[0055] Example 2

[0056] The alkaline compound used in this embodiment is calcium carbonate. High-iron bauxite, calcium carbonate and coke are fully mixed and ground to form pellets, and activated in a rotary kiln at an activation temperature of 750°C and an activation time of 30 minutes. After activation, the organic matter in the bauxite is decomposed, and the organic matter removal rate is 95%. After activation, the non-magnetic iron-rich phase is converted into a magnetic iron-rich phase with a conversion rate of 95%. After heavy magnetic separation, the iron recovery rate is 55%, the yield is 36%, and the iron concentrate TFe reaches more than 56%. The activated roasted ore is dissolved at high temperature using a calcified biomass method with a dissolution temperature of 275°C, which increases the dissolution rate by 5%, and the red mud aluminum-silicon ratio is less than 1%. The red mud can be further magnetically separated to increase iron recovery by 30%. After magnetic separation, the red mud can be used for building materials, soil remediation or soil conditioner.

[0057] Example 3

[0058] The alkaline compound used in this embodiment is sodium carbonate. High-iron bauxite and sodium carbonate are fully mixed and ground to form pellets, the carbonaceous material is replaced by hydrogen, and the activation reactor adopts a multi-stage cyclone heat exchanger. The activation temperature is 650°C, the activation time is 10 minutes, the non-magnetic iron-rich phase is transformed into the magnetic iron-rich phase, the conversion rate is 95%, and the organic matter decomposition rate is 94%. After heavy magnetic separation, the iron recovery rate is 50%, the yield is 35%, and the iron ore concentrate TFe reaches 56%; the activated roasted ore in the activator adopts calcification transformation high-temperature dissolution technology, the dissolution temperature is 280°C, the dissolution rate is increased by 5%, the alkali content in the red mud is 0.6%, and the red mud can be used for building materials, soil remediation or soil conditioner.

[0059] Example 4

[0060] The alkaline compound used in this example is potassium carbonate. High-iron bauxite, potassium carbonate, and biomass are thoroughly mixed and ground to form pellets. These pellets are then activated in a fluidized bed at 750°C for 30 minutes. The activated bauxite undergoes organic matter decomposition, with an organic matter removal rate of 95%. The non-magnetic iron-rich phase is converted to a magnetic iron-rich phase with a conversion rate of 95%. After heavy magnetic separation, the iron recovery rate is 50%, the yield is 35%, and the iron ore concentrate TFe reaches 56%. The activated roasted ore is dissolved at high temperature using a calcified potash method at 280°C, which increases the dissolution rate by 5%, reduces the red mud aluminum-silicon ratio to less than 1%, and transforms the red mud into a silicon-potash mineral compound fertilizer.

[0061] Example 5

[0062] The alkaline compound used in this embodiment is calcium oxide. High-iron bauxite, calcium oxide and biomass are fully mixed and ground to form pellets, and then activated in a rotary kiln at an activation temperature of 650°C and an activation time of 15 minutes. After activation, the organic matter in the bauxite is decomposed, and the organic matter removal rate is 92%. After activation, the non-magnetic iron-rich phase is converted into a magnetic iron-rich phase with a conversion rate of 90%. After heavy magnetic separation, the iron recovery rate is 50%, the yield is 35%, and the iron ore concentrate TFe reaches 56%. The activated roasted ore adopts the calcified biomass method for high-temperature dissolution, with a dissolution temperature of 276°C, and the dissolution rate is increased by 4%. The red mud aluminum-silicon ratio is less than 1%. The red mud can be further magnetically separated to increase iron recovery by 30%. Red mud can be used for building materials, soil remediation or soil conditioner.

[0063] The above describes the basic principles, main features, and advantages of the present invention. However, the above is only a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other implementation methods derived by any person skilled in the art without departing from the technical solution of the present invention should be included in the patent scope of the present invention.

[0064] In the description of the present invention, each embodiment focuses on the differences from other embodiments, and reference can be made to the same or similar parts between the embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0065] In the description of the present invention, relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined. Moreover, the term "comprises", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment comprising a series of elements includes not only those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the statement "comprising a ..." do not exclude the presence of other identical elements in the process, method, article or equipment comprising the elements.

[0066] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0067] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0068] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for roasting and activating high-iron bauxite, characterized in that: include: Step 1: Add an activator to the high-iron bauxite, mix it, grind it, and make it into pellets; Step 2: Activating the pellets in a closed reactor to obtain a magnetic iron-rich phase and activated roasted ore; Step 3: The activated roasted ore is subjected to calcification transformation high temperature dissolution technology to separate the solid and liquid products into sodium aluminate solution and calcification transformation red mud.

2. The method for roasting and activating high-iron bauxite according to claim 1, characterized in that: The activator is a mixture of a carbonaceous substance and an alkaline compound; and / or, a mixture of hydrogen and a basic compound.

3. The method for roasting and activating high-iron bauxite according to claim 2, characterized in that: The carbonaceous material is at least one of coal, coke, coke dust or biomass.

4. The method for roasting and activating high-iron bauxite according to claim 2, characterized in that: The basic compound is at least one of an alkali metal, an alkaline earth metal oxide, a hydroxide or a carbonate.

5. The method for roasting and activating high-iron bauxite according to claim 1, characterized in that: In step 2, the activation temperature is controlled to be 500° C.-750° C., and the activation time is 5-30 minutes.

6. The method for roasting and activating high-iron bauxite according to claim 2, characterized in that: When a mixture of carbonaceous material and alkaline compound is used as the activator, the pellet activation reactor adopts at least one of a packed bed moving bed, a fluidized bed or a rotary kiln, and the reactor is provided with an air lock for feeding and discharging materials.

7. The method for roasting and activating high-iron bauxite according to claim 2, characterized in that: When hydrogen and carbonaceous materials are used as activating agents, the gas activation reactor adopts at least one of a fluidized bed, a transport bed or a multi-stage cyclone heat exchanger.

8. The method for roasting and activating high-iron bauxite according to claim 1, characterized in that: The magnetic iron-rich phase is subjected to heavy magnetic separation.

9. The method for roasting and activating high-iron bauxite according to claim 1, characterized in that: The calcification transformation high temperature dissolution technology is at least one of a calcification carbonization high temperature dissolution technology, a calcification biomass high temperature dissolution technology or a calcification potash high temperature dissolution technology.

10. The method for roasting and activating high-iron bauxite according to claim 1, characterized in that: The dissolution temperature of the calcification transformation high-temperature dissolution technology is greater than 270°C.

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