121 results about "Bayer process" patented technology

The present invention relates to the technical field of red mud recycling and utilization, and in particular to a red mud iron extraction method based on electric arc furnace hydrogen plasma melting reduction technology, which utilizes electric arc furnace and hydrogen plasma technology to perform melting reduction to extract industrial pure iron from Bayer process red mud. The red mud iron extraction method comprises the following steps: pressing into billets; roasting; molten hydrogen plasma reduction; crushing; and screening. The present invention provides a red mud iron extraction method based on electric arc furnace hydrogen plasma melting reduction technology, which achieves the goal of efficiently extracting iron from red mud. Through an innovative process flow and optimized parameter settings, the method achieves the goal of efficiently and environmentally friendly extraction of high-grade iron from red mud, while achieving complete utilization of waste, thereby having significant economic and environmental benefits.

According to the method, sodium carbonate, limestone and coke are used as sintering aids and are uniformly mixed with the high-iron Bayer process red mud, the mixed material is sintered by adopting a one-step low-calcium reduction sintering process, and the sintered clinker is subjected to water leaching and dissolution to obtain a sodium aluminate crude solution and filter residues. And returning the sodium aluminate crude liquid to an aluminum oxide industrial production line to prepare aluminum oxide, and carrying out a hydrolysis alkali recovery process on filter residues to obtain industrial sodium carbonate. The hydrolysis residues are subjected to magnetic separation and recovery to obtain fine iron powder, and the remaining tailings are completely harmless and can be used as raw materials of building materials or used for soil backfilling. The process is characterized in that the one-step low-calcium reduction sintering temperature is 200-300 DEG C lower than the sintering temperature of a sintering method, and the energy consumption is low; na2CaSiO4 is a sintering target product, Ca2SiO4 generally generated by a traditional sintering method is not generated, the situation that Ca2SiO4 is hydrolyzed in the water leaching process to inhibit dissolution of aluminum oxide is avoided, and the recycling rate of aluminum oxide is increased while the using amount of limestone is greatly reduced. The technological process is simple, efficient, energy-saving and free of three-waste emission, and the method is a novel method capable of treating the high-iron red mud in a large-scale and reduction mode.

The invention belongs to the technical field of metallurgy, and discloses a hydrogen reduction dissolution method for bauxite. Comprising the following steps: mixing bauxite and circulating mother liquor to form raw ore pulp, adding a reducing agent, and performing Bayer process reduction dissolution; the reducing agent is hydrogen. According to the method, impurity-free and low-energy-consumption efficient dissolution is realized by introducing the gas-phase reducing agent hydrogen, red mud discharge is reduced from the source, and the recovery rate of valuable components is increased.

The preparation method of the low-sodium-oxide Bayer-process micro-powder aluminum hydroxide comprises the following steps: adding a seed crystal into a Bayer-process sodium aluminate solution to carry out a first-stage decomposition reaction so as to induce the generation and growth of an aluminum hydroxide crystal nucleus in the Bayer-process sodium aluminate solution; adding a sodium aluminate fine solution into the material subjected to the first-stage decomposition reaction for multiple times to perform a second-stage decomposition reaction so as to promote lattice reconstruction of the aluminum hydroxide crystal nucleus and removal of sodium ions in the sodium aluminate solution; carrying out solid-liquid separation on the material after the second-stage decomposition reaction to obtain a solid material; and washing and drying the solid material to obtain the micro-powder aluminum hydroxide. Through the synergistic effect of seed crystal induced crystallization, segmented decomposition reaction, temperature control, solid-liquid separation, washing and the like, the residual amount of sodium oxide is reduced from multiple links, and efficient preparation of the low-sodium-oxide micro-powder aluminum hydroxide is achieved.

The invention relates to the technical field of aluminum oxide clean production, in particular to a method for treating gibbsite through high-temperature calcification transformation based on source blocking, which comprises the following steps: mixing high-iron bauxite, a calcium compound and Bayer mother liquor, and then carrying out pulpifying to obtain ore pulp; conveying the ore pulp to a high-pressure dissolution reactor to obtain transformed red mud; separating and washing the transformed red mud by using a vortex rapid settling tank; and adding a binder into the washed and dried transformed red mud to prepare small balls, and roasting, hardening and solidifying to obtain ironmaking pellets. According to the method, Bayer process flow equipment can be directly adopted, the method has the characteristics of simple process and equipment, high production efficiency and the like, the transformed slag serves as a pellet raw material to be directly used for producing pellets, no solid waste is generated in the whole process, and finally harmless, high-valued and full-quantized consumption of the red mud is achieved; and the worldwide problem that a large amount of red mud is discharged in the aluminum oxide production process is thoroughly solved.

The invention relates to a process for preparing pure iron by using red mud, which is characterized in that the red mud is Bayer process red mud, i.e., solid waste residue formed by solid-liquid separation after aluminum oxide is dissolved out from bauxite through high temperature, high pressure and strong alkali in the process of producing aluminum oxide by adopting a Bayer process, so that the environmental burden caused by the Bayer process red mud can be solved; the method is beneficial for reducing carbon emission in the aspect of iron element extraction and promoting development of a green metallurgical technology, and is characterized by comprising the following steps: taking Bayer process red mud as a raw material, carrying out acid leaching on the Bayer process red mud to obtain a ferrous oxalate extract, calcining the ferrous oxalate to obtain iron oxide, and recycling the iron oxide. And dissolving the ferric oxide into a sulfuric acid solution to obtain a ferric sulfate solution, taking the ferric sulfate solution as an electrolyte in an electrolysis device, and obtaining electrolytic iron through the electrolysis device, so that the pure iron is prepared from the red mud.

The invention discloses a method for removing organic matters in an aluminum oxide solution produced by a Bayer process, which comprises the following steps: mixing evaporated discharged materials with biogas residues produced by biological gas production, stirring and adsorbing, and carrying out solid-liquid separation to obtain an adsorbed solution without the organic matters. The method disclosed by the invention can efficiently absorb organic matters in the sodium aluminate solution, effectively reduce negative effects of the organic matters on a production process, product quality and the like, greatly reduce foam of a decomposition tank, remarkably improve filtering and washing effects, reduce seed refinement, enable an aluminum oxide product to meet quality requirements, effectively improve the quality of the aluminum oxide product and reduce energy consumption; the production efficiency is improved, the production cost is reduced, the stability and sustainability of the production system process are enhanced, and the market competitiveness of products is improved.

The invention relates to the technical field of roadbed materials, and provides a Bayer process red mud roadbed material and a preparation method thereof.The Bayer process red mud roadbed material is prepared from, by weight, 100 parts of Bayer process filter pressing red mud, 1-30 parts of modified fly ash, 50-150 parts of a soil material, 2-10 parts of an accelerant and 0.01-0.8 part of a dispersing agent; wherein the modified fly ash is prepared from the following raw materials: fly ash, a silane coupling agent and 4-(2-hydroxyethoxy) benzaldehyde, and through the technical scheme, the problem that the Bayer process red mud roadbed material in the prior art is low in impermeability and mechanical property is solved.

The invention relates to the technical field of comprehensive utilization of colored industrial solid wastes, in particular to a method for selecting iron from Bayer process high-iron red mud. The method comprises the following steps: carrying out pre-screening and size mixing treatment on the Bayer process high-iron red mud to obtain mixed ore pulp; carrying out gradient magnetic separation on the mixed ore pulp to obtain first iron ore concentrate, magnetic separation tailings and multiple groups of magnetic separation concentrates; the magnetic separation concentrates are sequentially combined and graded, and coarse-fraction iron ore concentrates and fine-fraction iron ore concentrates are obtained; dividing the coarse-fraction iron ore concentrate to obtain a first group of coarse-fraction iron ore concentrate and a second group of coarse-fraction iron ore concentrate; mixing the first group of coarse-fraction iron ore concentrate with the magnetic separation tailings to obtain mixed mineral aggregate; the mixed mineral aggregate is separated again, and separated iron ore concentrate is obtained; and combining various iron ore concentrates to obtain second iron ore concentrates. According to the method, the grade and the recovery rate of the iron ore concentrate are synchronously improved through the synergistic effect of multi-section combined magnetic separation, material circulation re-separation and size grading optimization.

The application relates to the technical field of mineral pretreatment, in particular to a treatment method of high-iron bauxite; the treatment method comprises the following steps: performing selective crushing and grinding treatment and grading treatment on the high-iron bauxite to obtain coarse-grained bauxite and fine-grained bauxite; performing first and second heavy separation impurity removal on the coarse-grained bauxite to obtain heavy separation concentrate, heavy separation middlings and heavy separation tailings; performing grinding and magnetic separation treatment on the heavy separation concentrate to obtain magnetic separation concentrate and magnetic separation tailings; performing centrifugal ore dressing impurity removal treatment on the fine-grained bauxite to obtain centrifugal concentrate and centrifugal tailings; mixing the heavy separation middlings, the magnetic separation tailings and the centrifugal concentrate to obtain product concentrate; mixing the heavy separation tailings and the centrifugal tailings to obtain product tailings; the overall method has the characteristics of short process, low energy consumption, low production cost, low investment, high ore dressing efficiency and the like, and the obtained aluminum concentrate is suitable for Bayer process production of aluminum oxide.

The application provides a method for full resource recycling of Bayer process red mud, valuable elements such as aluminum, iron, calcium, silicon and gallium in the red mud are leached into a solution, main elements (aluminum, iron, calcium and silicon) are separated first to obtain industrial products such as iron ore powder, silica gel, gypsum and water purifying agent, and gallium elements are enriched, gallium is separated and extracted from the solution through extraction, the purpose of full resource recycling of the Bayer process red mud is achieved, high concentration enrichment of the gallium elements is realized, valuable elements are not wasted, and the method has the advantages of less interference factors, high extraction efficiency, saved extraction agent and back extraction agent.

Method for producing a chemically and physically stable, neutral, non-saline inorganic product from bauxite residues (1), comprising the steps of: (i) providing (1100) a washed and thickened bauxite residue (1), (ii) in a so-called acidification step (1200), reacting the washed and thickened bauxite residue (1) with a sufficient quantity of a monoprotic Bron sled acid (10) to achieve a final target pH between 5.5 and 8.5 at an addition rate such that the pH never drops below a value of 3.0, (iii) in a so-called separation step (1300), separating soluble reaction products from the remaining solids( 7), (iv) in a so-called post-acidification washing step (1400), washing the remaining solids (7) obtained in the separation step with a washing liquid (17). Said product (21) can be used as a growth medium or soil for growing plants, in pure form or in mixture with natural soil materials of geological or biological origin.

The utility model provides a system for treating low-temperature Bayer process red mud, and relates to the field of solid waste recycling. Comprising Bayer process low-temperature red mud, a composite additive, a weighing device and a dissolver, the dissolver is communicated with a dilution tank, the dilution tank is communicated with a filter unit, the filter unit is respectively communicated with a multi-stage washing device and a seed crystal decomposition tank, the multi-stage washing device is communicated with a drying device, and the drying device is communicated with a first warehouse; the seed crystal decomposition tank is communicated with a filter, the filter is respectively communicated with an evaporation concentration device and a roasting furnace, the roasting furnace is communicated with a second warehouse, and the evaporation concentration device is communicated with a dissolver; according to the utility model, the iron-calcium composite additive is adopted as a main reaction auxiliary agent and is subjected to accurate proportioning and directional reaction with the high-iron guineite bauxite, aluminum and sodium which are lost in secondary reaction and enter the red mud are separated and recovered in the dissolution process, and the red mud is converted into an iron ore concentrate powder product in the production process, so that the efficient separation and utilization of aluminum and iron are realized; the method is energy-saving, environment-friendly, low in cost and remarkable in economic benefit and environmental benefit.

The invention belongs to the technical field of metallurgical slag resource utilization, and particularly relates to a nickel smelting slag recycling process. Comprising the following steps: mixing and drying stainless steel pickling sludge, Bayer process red mud and coke powder to prepare iron-containing coke powder; setting a slag pot position and a spray gun position; when the molten nickel smelting slag falls down, iron-containing coke powder is sprayed out at a constant speed through argon by using a spray gun, the molten nickel smelting slag is blown away, and then a reduction reaction is carried out; a fluxing agent is added into the reduced molten nickel smelting slag, then vacuumizing is conducted, magnesium is reduced and evaporated, magnesium steam is collected and cooled, and elementary substance magnesium and magnesium-removed molten nickel smelting slag are obtained; coke powder and metal carbide powder are added into the magnesium-removed molten nickel smelting slag, cooling is conducted after reaction, reaction materials are taken to be crushed, ground and magnetically separated, Fe-Ni-Cr enriched alloy is obtained and used for a steel plant, remaining materials are used as aggregate in a cement plant, the production process is simple, the recovery process is short, energy consumption of equipment can be greatly reduced, and the metal recovery rate is increased.

This invention provides a method for treating red mud, comprising the following steps: First, red mud slurry from an aluminum plant is fed into a red mud storage tank, filtered to obtain an alkaline solution and red mud filter cake. The alkaline solution is returned to the aluminum plant, and the red mud filter cake is mixed with additives to form a red mud mixture. Second, the red mud mixture is fed into an electromagnetic rotary kiln for calcination. Within the electromagnetic rotary kiln, from the inlet to the outlet, the temperature varies in different sections: the first section is 25-600℃, the second section is 600-800℃, the third and fourth sections are 800-1000℃, and the fifth section is below 100℃. Third, the output material from the electromagnetic rotary kiln is subjected to dry magnetic separation. The magnetic separation includes two stages: the first stage involves weak magnetic separation of the cooled material to obtain iron concentrate powder and the first tailings; the second stage involves strong magnetic separation of the first tailings to obtain middlings and tailings. The middlings are titanium dioxide, and the tailings are geopolymers. This invention achieves zero-emission standards for the entire production process, has low production investment costs, and is easily compatible with the Bayer process in China.

Provided herein are methods and systems for producing alumina trihydrate (Al(OH)3) and / or alumina (Al2O3). The methods and systems utilize energy extracted from the aluminum-water reaction to power the conversion of various aluminum sources to alumina trihydrate.

The present application relates to the field of environmental protection material and carbon capture technology, in particular to a kind of red mud-based carbon dioxide capture adsorbent and its preparation method.It is composed of the following components by weight: activated red mud 60~80 parts;Alkali metal modification component 15~30 parts;Porous carrier 5~10 parts;Binder 3~8 parts;Auxiliary activator 2~5 parts.Activated red mud is obtained by removing iron from bayer process red mud by magnetic separation to iron content≤5wt%, then drying, calcining and crushing.The preparation method includes raw material pretreatment, mixing and dispersion, molding, activation and cooling.The obtained adsorbent has a static adsorption capacity for CO2≥2.8mmol / g, a 20-cycle retention rate≥90%, a compressive strength≥8MPa, and a raw material cost of 800~1200 yuan / t, realizing high-value utilization of red mud and low-cost carbon capture, and being suitable for flue gas CO2 capture in power generation, steel, coal chemical industry and other industries.

The invention discloses a red mud heat treatment protective coating and application thereof in high manganese steel heat treatment, the red mud heat treatment protective coating is composed of Bayer process red mud, alkaline glass, boric acid, borax, silica sol, bentonite and calcium carbonate, and the red mud heat treatment protective coating is used for heat treatment after being coated on the surface of a high manganese steel casting and dried. The raw materials in the coating are synergistic, and a high-temperature-resistant framework is combined with a rapid densified glass phase, so that diffusion of oxygen and carbon is effectively blocked, and oxidation and decarbonization of high-manganese steel during heat treatment at 1000-1150 DEG C are prevented; silica sol enhances adhesion, and calcium carbonate improves hardness. The coating naturally falls off after heat treatment, post-treatment is simplified, industrial solid waste is utilized as raw materials, cost is low, environment friendliness is good, and the heat treatment quality and efficiency of the high-manganese steel are remarkably improved.

The invention relates to the technical field of waste heat recovery of Bayer process aluminum oxide production, in particular to a seven-effect five-flash condensate water waste heat grading system and an aluminum oxide production device. According to the system, the first-effect condensate water and the second-effect condensate water are divided into two independent loops according to the thought of'temperature alignment and stepped recovery ', namely the first-effect condensate water and the second-effect condensate water, and the condensate water cooled by the two loops finally converges into the same recovery tank and then is pumped back to a boiler or a deaerator. Due to the fact that heat needed by the stock solution, the washing water and the secondary steam condensate water is all borne by original directly-discharged first-effect waste heat and second-effect waste heat, the amount of new steam needing to be supplemented by the evaporator is correspondingly reduced. And meanwhile, the first-effect heat transfer temperature difference of the evaporator is reduced, the system can maintain the seven-effect total temperature difference under the lower new steam pressure, and closed-loop energy saving of replacing new steam with waste heat is achieved.

The present application relates to the field of alumina, and in particular to a method for improving the decomposition rate of semen in alumina produced by the Bayer process; the method comprises: using a material obtained from a decomposition system in the Bayer process as a raw material, performing multiple continuous grindings until the aluminum hydroxide in the material reaches a preset particle size to obtain active seed crystals; adding the active seed crystals to the mother liquor in the decomposition system for decomposition to improve the decomposition rate of semen; wherein the preset particle size comprises a first preset particle size condition and a second preset particle size condition; the grinding comprises grinding by sand milling; by taking the slurry of the decomposition system itself for re-grinding and then returning it to the decomposition system, while controlling the amount of slurry added after grinding and the seed crystal particle size in the slurry, the decomposition rate of semen can be achieved to be above 52%.

This invention relates to a method and system for the combined processing of Bayer process red mud and low-grade bauxite. The method includes: separately detecting the aluminum and silicon content in the red mud and bauxite, mixing the red mud and bauxite according to the detection results to achieve an aluminum-to-silicon ratio greater than 1 in the resulting raw material, adding a calcination aid, and calcining to obtain clinker. The clinker undergoes multiple cycles of water leaching and primary desilication treatment until the aluminum-to-silicon ratio in the solution is greater than 300 and the vanadium content reaches 2 g / L, at which point deep desilication is performed. The deep desilication solution is then carbonated to extract aluminum. Ammonium salts are added to the resulting solution to further extract vanadium. The final solution is crystallized and used as a calcination aid. The water leaching residue from the water leaching treatment is acid-leached, aged, and hydrolyzed to polymerize, yielding calcium sulfate, silica gel, and a water purification agent, respectively. This invention effectively utilizes both major and rare elements, solving the problems of red mud accumulation and the ineffective utilization of low-grade bauxite.

The application relates to the harmless treatment technology field of solid waste, in particular to a drying method of Bayer process red mud. The drying method comprises the following steps: mixing and stirring Bayer process red mud filter cake and a compounded additive to obtain mixed red mud material; wherein the compounded additive comprises an anti-agglomeration additive and an anti-bonding additive; and drying the mixed red mud material in a rotary kiln to obtain red mud products. The drying method is cooperated with the accurate control of the process parameters of the rotary kiln (external regulation guarantee) through the physical property regulation (internal regulation core) of the compounded additive, cuts into the interaction between the red mud material particles in the Bayer process red mud filter cake, the material fluidity, the environment and the mechanical action in the drying process from multiple dimensions, realizes the synchronous reduction of the viscosity and the agglomeration rate of the red mud products, and finally the red mud products with the water content of less than 9.0% and the average particle size of the agglomerated blocks of less than or equal to 4 mm can be obtained.

The invention discloses emulsion with a stable thickening agent and application of the emulsion to production of aluminum oxide through the Bayer process, and relates to the technical field of emulsion, the emulsion comprises an oily chemical, the thickening agent, water and an emulsifying agent, the oily chemical is a crystal growth auxiliary CGM used in production of aluminum oxide through the Bayer process, the thickening agent is a substance capable of increasing the viscosity of a water phase, and the emulsifying agent is an emulsifier capable of increasing the viscosity of the water phase. The emulsifier is a surfactant. According to the stable emulsion of the thickening agent and the application of the stable emulsion in production of aluminum oxide by a Bayer process, the thickening agent can realize uniform dispersion of oily CGM without a large amount of emulsifier by increasing the aqueous phase viscosity stable emulsion, the interference of the traditional emulsifier on the coarsening performance of the CGM is avoided, and the application effect of the stable emulsion is superior to that of the traditional emulsion and even exceeds that of the oily CGM; and the proportion of particles larger than 45 microns in the alumina trihydrate particles can be effectively increased.

The invention provides a method for removing organic matters in bauxite, and belongs to the field of aluminum oxide production. The method comprises the following steps: carrying out ball milling on crushed bauxite and alkali liquor to obtain raw ore pulp containing bauxite with set granularity; carrying out organic matter removal reaction on the raw ore pulp, and then carrying out solid-liquid separation to obtain bauxite without organic matters and organic matter leachate; adding an adsorbent into the organic matter leachate to adsorb and remove organic matters in the organic matter leachate to obtain mixed slurry; carrying out solid-liquid separation on the mixed slurry to obtain organic matter-removed alkali liquor; and the organic matter-removed alkali liquor is circularly used for ball milling of bauxite. Before bauxite enters a high-temperature dissolution process, organic matters such as humic acid and oxalic acid are directly removed through a wet process, so that the organic matters are prevented from entering a Bayer process system, and the production stability of aluminum oxide can be effectively guaranteed.

The present invention discloses a method for joint production of alumina and iron smelting by the Bayer process. Firstly, the raw materials and auxiliary materials are mixed with bauxite containing a high content of iron oxide. Then high-temperature digestion is conducted on the mixed materials. Through this digestion process, a mixed slurry of red mud and sodium aluminate solution is obtained. Subsequently, this mixed slurry is subjected to sedimentation and separation, yielding red mud and sodium aluminate solution respectively. This red mud-based iron concentrate is proportionally mixed with the pre-set iron concentrate and calcium compounds, and then undergoes high-temperature treatment to produce a mixed sinter for use in an iron-smelting blast furnace. When the mixed sinter is fed into the iron-smelting blast furnace, pure iron products are obtained. Finally, the sodium aluminate solution is subjected to seed precipitation and calcination treatment, resulting in the production of alumina.

The invention discloses a method for producing aluminum oxide by using carbide slag instead of lime, which comprises the following steps: in the process of dissolving out bauxite by a Bayer process, adding carbide slag into circulating mother liquor, and carrying out dissolution treatment. According to the method for producing the aluminum oxide by using the carbide slag instead of the lime, the dissolution effect of the bauxite is equivalent to that of the traditional lime. The calcium-containing characteristic of the carbide slag is utilized, the effect of lime in the Bayer process dissolution process is ingeniously replaced, the effects of turning waste into wealth and recycling waste are achieved, and remarkable economic and social benefits are achieved.

The utility model discloses a red mud separation device for producing aluminum oxide by Bayer process, and particularly relates to the technical field of red mud separation in aluminum oxide production, which comprises a barrel body, an inner cavity of the barrel body is fixedly connected with a partition plate, the bottom of the inner cavity of the barrel body is fixedly connected with a support table, and the top of the support table is provided with a clamping groove. And a filter cartridge is arranged in the middle of the clamping groove. Firstly, the motor is started to control the first stirring plate to stir and mix a stock solution and a flocculating agent, the settling efficiency is improved, a second valve is opened to input mixed liquid into the top of the supporting table, red mud and the liquid are separated through the filter cartridge, and a second stirring plate and a connecting insertion plate are driven by a rotating rod to rotate, so that the settling efficiency is improved. Liquid can be centrifugally stirred, the liquid is filtered by the filter cartridge and flows out of the filter cartridge, and the liquid is scraped by driving the scraping rod and the scraping strip, so that the automatic cleaning effect is realized, sediment is conveniently discharged, and the cleaning effect is improved.

This application provides a method for preparing high-whiteness aluminum hydroxide based on oxalate filter cake, belonging to the field of aluminum hydroxide preparation. The method includes: adding sodium oxalate circulating seed to the Bayer process seeding mother liquor to obtain an oxalate filter cake containing aluminum hydroxide; adding sodium carbonate to the oxalate filter cake to adjust the alkali ratio to 0.85–1.15, and adding lime to the oxalate filter cake to obtain a mixture; sintering the mixture to obtain sintered clinker; dissolving the sintered clinker to obtain a sodium aluminate solution; and seeding the sodium aluminate solution to obtain high-whiteness aluminum hydroxide. This application, through precise coupling of process parameters and a full-process design of the impurity control chain, simultaneously achieves deep removal of key impurities such as Fe and Si during the oxalate removal process, transforming the oxalate filter cake from waste into a high-quality raw material for high-whiteness aluminum hydroxide, thus combining the removal of organic matter from oxalate and the preparation of high-whiteness aluminum hydroxide in the Bayer process alumina production.

The invention relates to the technical field of metal material recycling, in particular to a comprehensive utilization method for coupling high-iron bauxite calcified biomass and iron powder. S2, transforming and dissolving out; s3, carrying out liquid-solid separation; s4, pelletizing the transformed slag; and S5, blast furnace ironmaking pellets are prepared. Under the double coupling action of calcified biomass and iron powder, Fe2O3 in the bauxite is completely transformed into magnetite, an alkali-giving phase in an equilibrium solid phase is transformed into an alkali-free phase under the action of a calcified compound, the alkali consumption in the whole process is reduced by 80% or above compared with a Bayer process, and the final transformed red mud can be directly roasted to prepare blast furnace ironmaking pellets. The method has the advantages that the process and equipment are simple, the production efficiency is high, Bayer process equipment can be directly adopted in the dissolution process, and finally harmless, high-valued and full-quantized digestion of the red mud is achieved.

The invention discloses microwave activated red mud-biomass solid waste magnesium oxychloride aggregate and a circulation method, and belongs to the technical field of solid waste recycling and negative carbon building materials. The method comprises the following steps: mixing Bayer process red mud and biomass solid waste according to a mass ratio of 3: 1-1: 1, and carrying out microwave activation at 500-1200 DEG C for 10-60 minutes; carrying out magnetic separation on the activated material to obtain an iron ore concentrate-biomass charcoal composite material which can be used as a wave-absorbing material, so as to obtain low-alkali activated red mud residues; 10-50 parts of the residues, 15-40 parts of light calcined magnesia powder and 15-40 parts of a magnesium chloride solution are mixed, the molar ratio of magnesium oxide to magnesium chloride is 6-9, and solid waste aggregate is obtained after forming and curing; the waste aggregate is regenerated into active powder after being subjected to heat treatment at 400-800 DEG C for 0.5-2 hours, and new aggregate can be circularly prepared. According to the method, red mud dealkalization and iron recovery, high-value utilization of biomass and carbon sequestration and stability augmentation and closed-loop circulation of aggregate are synchronously realized.