57 results about "Dealkalization" patented technology

The invention discloses an efficient consolidation agent for tailings in an underground mine filling mining method and a preparation method thereof, and relates to the technical field of consolidation agents, the consolidation agent is prepared from a gelling base material, a nano reinforcing agent, a chemical exciting agent and an organic fiber reinforcing agent according to a specific mass ratio; aiming at the problems of unstable volume, insufficient strength and the like of a traditional consolidation agent, through high-temperature calcination of the steel slag to eliminate harmful components, dealkalization treatment of the red mud, acid activation of the phosphogypsum and volcanic ash reaction of the fly ash, the volume stability and the gelling activity of a filling body are remarkably improved, and the consolidation agent is suitable for complex underground environment requirements; aiming at the pain points of low early strength, weak interface bonding and the like of the consolidation agent, the cohesion is improved by strong bonding of the surface-modified nano SiO2 and a gelling base material, a chemical exciting agent is added to cooperate with CO2 carbonization to generate nano crystal nucleuses, hydration sites are provided, a pore structure is optimized, bleeding is inhibited, the fluidity and stability of slurry can be effectively improved, and the consolidation effect is good. And the requirements of underground filling homogeneity and pumpability are met.

The invention belongs to the technical field of environmental protection and solid waste recycling, and particularly relates to a method for passivating and completely dealkalizing red mud and reserving valuable metal components. According to the method, the amount of added accurate dealkalization acid is limited through an acid amount formula, a weak acid reaction environment is created, only alkaline substances contained in the red mud are limited to participate in a neutralization reaction by controlling parameters such as passivation dosage, liquid-solid ratio, stirring time and temperature, water-soluble alkali salt is generated, then the alkali salt is separated and discharged in a filtering mode, and the water-soluble alkali salt is obtained. And preparing a dealkalized red mud filter cake. In the whole reaction process, Fe2O3, TiO2 and other metal oxide components are passivated by the passivator due to a weak acid environment, and the oxidation effect is basically completely retained in the dealkalized red mud filter cake. The alkali content of the dealkalized red mud is zero, the iron content is increased, and the dealkalized red mud can be directly used as refined iron powder or a catalyst, an adsorbent, a building material, a roadbed material and the like.

The invention relates to the technical field of float glass production, and discloses a high-aluminum float glass dealkalization uniformity monitoring method which comprises the following steps: S1, cutting glass subjected to dealkalization treatment, placing the cut glass in a container, soaking the cut glass in a weak acid solution, cleaning the soaked glass, detecting the state of roller marks on the surface of the glass, and increasing the usage amount of SO2 in a tin bath when the occurrence proportion of the roller marks on the glass exceeds 10%; s2, soaking the glass in a reinforcing acid solution, cleaning and detecting the dimness state of the glass, and reducing the usage amount of SO2 in a tin bath when the dimness proportion exceeds 10% or above; through the operation, the dealkalization amount of the glass is controlled. According to the method, the roller marks, the obscuration condition and the proportion are generated after glass soaking treatment, dealkalization on the surface of the glass is monitored, the dealkalization uniformity can be effectively controlled, and the method is simple in technological process, does not need to add expensive equipment and is easy to apply and popularize.

The invention belongs to the technical field of solid waste resource utilization, and particularly relates to a red mud-based multifunctional water treatment agent and a preparation method thereof. The method comprises the steps of red mud dealkalization, drying and crushing, acid dissolution reaction, pH regulation and control, function enhancement, slow-release carrier forming and the like, and by introducing a modified polyacrylamide functional additive and a compound flocculant, the removal capacity of the treatment agent on heavy metal ions, organic pollutants and high-hardness ions is effectively improved; sodium alginate-polyvinyl alcohol is adopted to construct an ionic crosslinking type slow release system, so that the combination of long-acting release and broad-spectrum purification functions is realized. Compared with the prior art, the method has the advantages that resource utilization of the red mud waste is achieved, and the prepared water treatment agent has the remarkable advantages of being stable in structure, high in adaptability, high in treatment efficiency and the like.

This invention discloses a lithium slag dealkalization treatment agent and a method for the resource utilization of lithium slag in building materials, comprising the following raw materials in parts by weight: 50-80 parts sodium hydroxide, 30-50 parts water glass, 5-15 parts polycarboxylate superplasticizer, and 10-20 parts calcium carbonate. This invention has the advantage of being environmentally friendly and solves the problems of existing lithium slag resource utilization methods, such as the inconvenience of preparing high-strength, high-insulation building materials from waste lithium slag, insufficient strength of lithium slag building materials making them unsuitable for load-bearing structures or high-load scenarios, limiting their use to low-strength filler materials or non-structural components, significantly reducing their economic value, and poor insulation performance failing to meet energy-saving building standards, resulting in a lack of competitiveness in scenarios requiring thermal insulation such as walls or roofs.

The application discloses a kind of red mud gradient depth purification-rare earth-radioactivity synergistic target purification method, by " hierarchical pretreatment and microwave modification→three-stage gradient dealkalization→rare earth-radioactivity synergistic target purification→full quantization recycling" four-stage integrated process, realize red mud harmless and high-value utilization.The three-stage gradient dealkalization uses microwave-CO2-biological synergic system, after dealkalization pH≤8.0, Na2O content<1%;Rare earth-radioactivity purification is extracted by HDES and coupled with multi-ligand magnetic material system, light rare earth recovery rate≥95%, middle heavy / rare earth recovery rate≥90%, U / Th removal rate≥95%;Full quantization recycling realizes red mud total utilization rate≥98.5%, wastewater reuse rate≥95%, every ton of red mud fixed CO2≥0.2 tons.The application is suitable for various high-alkali, containing radioactive and rare earth red mud treatment, with environmental benefits and economic benefits.

According to the biomass dealkalization method and the prepared low-alkali biomass fuel, the cavitation effect formed by propagation of high-frequency ultrasonic waves in liquid is utilized, instant high pressure of hundreds of atmospheres can be generated in microseconds, and along with the local high temperature phenomenon, the biomass structure can be rapidly destroyed, and the low-alkali biomass fuel can be used for dealkalization of biomass. The internal alkali metal and alkaline earth metal elements are promoted to be quickly released; the catalyst interacts with carbon dioxide to form a dissolved or precipitated state, so that the removal efficiency of alkali metal and alkaline earth metal is greatly improved. Compared with the prior art, the method effectively solves the problem that a conventional method is low in efficiency under the conditions of short time and large solid-to-liquid ratio; and a large amount of acid solution is not needed, so that the dealkalization cost and the equipment corrosion risk are reduced. Therefore, the technological process is simplified, an efficient and environment-friendly technical choice is provided for large-scale industrial application, and the method has a wide application prospect.

The invention discloses a process for dealkalizing and deeply reducing red mud through gradient temperature control treatment, which comprises the following steps: 1) accurately metering raw materials and grinding; 2) feeding the ground raw materials into a red mud stirrer, and stirring at a gradient rotating speed; 3) feeding the stirred and mixed raw materials into a granulator for granulation, and pressing the materials into particle materials with the particle size of 5-15mm; 4) feeding the particle material into a dealkalization solid-phase reaction device, and forming a particle material after a solid-phase reaction in a reducing atmosphere; (5) feeding the particle material after the solid-phase reaction into a cooling machine, and slowly cooling in a furnace by adopting a nitrogen direct circulating cooling method; 6) crushing the cooled material by a crusher until the particle size is less than 5mm; 7) performing magnetic separation on the ground powder by a high-gradient magnetic separator.According to the method, efficient dealkalization and iron element reduction separation are realized through high-temperature dealkalization pre-reduction and high-temperature deep reduction melt separation.

The present invention relates to a dealkalization device and method for producing red mud in the alumina industry. The device comprises: at least one mixer; at least one settling tank; wherein the at least one settling tank and the at least one mixer are sequentially connected in series and spaced apart; a dealkalization reaction tank for dealkalizing an underflow, wherein, in the dealkalization reaction tank, lime milk is added to the underflow to obtain a red mud-lime milk mixture, which is then introduced into high-temperature steam for chemical reaction to obtain a red mud residue; the inlet of the dealkalization reaction tank is connected to the outlet of the last settling tank; a filter press for filtering the red mud residue to obtain a filter cake and a filtrate; wherein the inlet of the filter press is connected to the outlet of the dealkalization reaction tank; a red mud storage tank for storing the filter cake; wherein the red mud storage tank is connected to the outlet of the filter press. The device solves the technical problems in the prior art of the traditional lime Bayer process for producing alumina, such as large alumina loss, large alkali loss, and high energy consumption and production cost.

The invention provides a microwave hydrothermal curing red mud-based building block paving material and a preparation method thereof, and belongs to the technical field of industrial solid waste resource utilization. The preparation method comprises the following steps: adding water into raw materials comprising dealkalized red mud, carbide slag, ardealite, steel slag powder and aluminum tailings, uniformly mixing, carrying out compression molding, putting into a microwave reaction kettle, and carrying out hydrothermal curing treatment under the conditions that microwave irradiation is carried out and the temperature is 100-200 DEG C and the pressure is 0.2-0.4 MPa, so as to obtain the red mud-based building block paving material. According to the preparation method disclosed by the invention, the curing rate of heavy metal ions in an industrial solid waste material is improved and the radioactive hazard of the material is weakened through a quadruple synergistic mechanism of dealkalization pretreatment, low-temperature hydrothermal crystallization, heavy metal ion curing and radiation shielding, so that the red-mud-based building block paving material has relatively high strength; the problem of saltpetering of the red mud is effectively solved, and the application requirements of municipal engineering, river dike dam protection, hazardous waste protection and other scenes can be met.

The invention discloses a method for recovering iron, aluminum and sodium in red mud, which comprises the following steps: mixing the red mud and an alkaline solution, and introducing hydrogen into high-temperature and high-pressure equipment to react; carrying out solid-liquid separation on the slurry after reaction, and carrying out magnetic separation after solid-phase grinding to obtain concentrate and tailings; and adding a calcium-containing additive aqueous solution into the tailings for dealkalization reaction to obtain dealkalized residues and dilute alkali liquor. Red mud, an alkaline solution and hydrogen are stirred and reacted in high-temperature and high-pressure reaction equipment, (aluminum) hematite and (aluminum) goethite in the red mud are completely converted into ferroferric oxide, the purpose of extracting aluminum in the red mud is achieved, solid-liquid separation is conducted on slurry after the reaction, ferroferric oxide in a solid phase is separated through magnetic separation, and the iron content in concentrate is high; the method can cooperate with large-scale absorption in the iron and steel industry, and also considers recovery of iron minerals; comprehensive recovery of iron, aluminum and sodium in the red mud is realized, and the method has the advantage of environmental friendliness.

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.

The application relates to a paste filling material, raw material components of the paste filling material comprising: a red mud-based active material, a first red mud, a pumping agent and a stabilizer; wherein the red mud-based active material is obtained by sintering of dealkalization red mud and industrial by-product gypsum, raw material components of the dealkalization red mud comprising a second red mud and calcium oxide-rich slag. The application converts the red mud into the paste filling material through two-stage utilization, has the advantages of simple process and low cost, and has excellent performances such as good fluidity, high mechanical strength and slight expansion, reaches the performance requirements of the mine filling material, and realizes high-content utilization of the red mud in the filling material field.

The invention relates to a method for preparing calcium aluminate by using alkaline residues, which comprises the following steps: adding an induced settling agent into alkaline residue slurry to promote the growth of calcium carbonate crystal grains in the alkaline residue slurry and further promote the settling of calcium carbonate, aluminum calcium carbonate and other products so as to facilitate subsequent better solid-liquid separation; carrying out dealkalization type liquid-solid separation treatment on the sedimentation liquid to obtain low-sodium modified alkaline residues and catalytic filtrate; reacting the catalytic filtrate with aluminum ash to obtain sodium aluminate, ammonia gas, methane and hydrogen; then carrying out solid-liquid separation to obtain modified aluminum ash with less leached fluorine and less volatile ammonia; and preheating and calcining the modified alkaline residues and the modified aluminum ash to obtain a target calcium aluminate product. The preparation method provides a thought for preparing high-quality calcium aluminate from the alkali residues discharged in the Bayer process aluminum oxide production process.

The present invention provides a vanadium extraction tailings calcification reduction dealkalization method. The method comprises the following steps: pre-treating the vanadium extraction tailings with a composite low-temperature curing agent for pelletization to prepare a silicon-free pellet raw material that releases CO2 at high temperature; adopting a hot air drying-microwave consolidation process to strengthen the strength of the pellets; and then using a rotary kiln for reduction roasting, so that the alkali metals in the vanadium extraction tailings enter the gas phase and are removed through dust removal. The obtained slag phase has high iron and vanadium metallization rates and can be directly used in a blast furnace. The alkali metals in the vanadium extraction tailings are effectively removed, enabling the recycling of the vanadium extraction tailings in the ironmaking process, improving the recovery rate of valuable elements in the vanadium extraction tailings, and increasing the blast furnace's ability to process the vanadium extraction tailings.

The invention discloses fly ash-red mud based ultrafine powder and a preparation method and application thereof.The fly ash-red mud based ultrafine powder is prepared from, by weight, 50-70 parts of modified fly ash, 10-35 parts of dealkalized red mud, 4-10 parts of waste glass micro powder and 4-10 parts of nanometer silicon-aluminum sol, the dealkalized red mud is prepared from red mud through calcination-secondary leaching. The fly ash-red mud-based ultrafine powder prepared by the invention can replace S95-grade mineral powder, is remarkably better in working performance, mechanical property and durability after being used for preparing sea sand concrete, can effectively prolong the service life of marine environment concrete engineering while reducing the production cost of the sea sand concrete, and has higher engineering application value.

The present application belongs to the technical field of environmental protection and solid waste recycling, and particularly relates to a method for passivating, completely removing alkali and retaining valuable metal components of red mud. The present application limits the precise alkali removal acid amount by an acid amount formula, creates a weak acid reaction environment, and limits only the alkali substances contained in the red mud to participate in the neutralization reaction by controlling the passivation agent amount, liquid-solid ratio, stirring time and temperature and other parameters, to generate alkali salt dissolved in water, and then separates and discharges the alkali salt by filtration to prepare the alkali-removed red mud filter cake. During the whole reaction process, the metal oxide components such as Fe2O3 and TiO2 are basically completely retained in the alkali-removed red mud filter cake due to the weak acid environment and the passivation and oxidation of the passivation agent. The alkali-removed red mud obtained by the present application contains zero alkali and increased iron content, and can be directly used as fine iron powder or catalyst, adsorbent, building material, roadbed material and the like.

The invention discloses a red mud all-element high-value resource recycling process, and relates to the technical field of red mud. Sodium silicate and sodium alkali are efficiently separated through washing of the double-helix mud washing machine, concentration of the thickener, dealkalization leaching of ammonium chloride, classification of the hydrocyclone, targeted treatment of coarse and fine particles, high-value utilization of silicon alkali overflow liquid, two-stage membrane electrodialysis and the like; the problems of recovery of sodium silicate and electronic-grade silica sol in the red mud, removal and conversion of sodium hydroxide into high-purity sodium hydroxide and full-component decomposition, separation and enrichment of valuable elements (silicon, aluminum, iron, titanium, vanadium, heavy metals and three-rare elements) are completely solved, and finally full-element utilization of the red mud, especially enrichment of alkali-soluble three-rare elements, is realized. The commercial value of the red mud is far higher than that of bauxite, and a feasible industrial path is provided for harmless, recycling and high-value utilization of the red mud.

The invention relates to the technical field of mine filling materials, in particular to an alkali-activated red mud filling material and a preparation method and application thereof. The invention provides an alkali-activated red mud filling material, which is prepared from the following raw materials in parts by weight: 70 to 90 parts of red mud, 10 to 20 parts of a dealkalizing agent, 1 to 3 parts of a dealkalizing-coagulating aid, 10 to 30 parts of an auxiliary cementing material, 0.1 to 0.5 part of a retarder, 0.1 to 0.3 part of a water-retaining agent and 0.1 to 0.3 part of an interface reinforcing agent, wherein the weight part of the red mud is the weight part of the dry basis red mud. The alkali-activated red mud filling material prepared by adopting a method combining a dealkalization technology and an alkali-activated technology provided by the invention is faster in coagulation, higher in compressive strength and lower in bleeding rate, meanwhile, the preparation method solves the problems that a large amount of red mud is high in dealkalization cost and difficult to fully utilize after dealkalization, and has great practical application value.

The invention belongs to the technical field of red mud solid waste treatment, and particularly discloses a strong-basicity red mud-based directional dealkalization environment-friendly filling material and a preparation method thereof. The red-mud-based environment-friendly filling material provided by the invention comprises the following components: red mud, cement, a biomass organic acid modifier and water. The preparation method comprises the following steps: inputting the red mud into a paste storage thickener; mixing the thickened red mud, cement and water, and stirring to obtain initial slurry; adding a biomass organic acid modifier, and continuously stirring to obtain slurry; and filling and curing to obtain the red-mud-based environment-friendly filling material. The invention provides a directional dealkalization technology taking biomass-based organic acid as a core neutralizer, silicon-aluminum activity of the red mud is synchronously activated, auxiliary cementing materials such as slag are not needed, the superiority of biomass-based dealkalization is verified through experimental data, and three targets of dealkalization environmental protection, strength standard reaching and waste treatment with waste are achieved.

The application discloses a method for dealkalization of red mud and resource utilization, characterized in that the method comprises the following steps: adding red mud and titanium dioxide waste acid into deionized water, adding hydrogen peroxide, fully stirring to form a mixed solution, filtering, obtaining dealkalization clear liquid and dealkalization residue; adjusting the pH of the dealkalization clear liquid to neutral, performing solid-liquid separation, obtaining second residue and second clear liquid; adding calcium oxide to the second clear liquid, collecting the gas generated in the process by spraying, performing solid-liquid separation, obtaining third residue and third clear liquid and recycling; and recycling after evaporation and concentration of the spraying liquid. The application enriches the iron content in the dealkalization red mud while dealkalizing the red mud, which is beneficial to iron recovery; the obtained second residue is iron hydroxide, which can be directly used as iron concentrate for recovery and smelting; the third clear liquid is concentrated by evaporation to obtain concentrated ammonia water for continuous reuse, thereby reducing ammonia water consumption; a small amount of solid waste calcium sulfate is generated, and solid waste reduction, resource utilization and harmlessness are truly realized.

The utility model discloses a device for improving warping of raw sheet glass, which comprises a slag box, an air inlet pipe, an air outlet pipe and an air outlet pipe, the adjusting structure is communicated with the vent hole and used for adjusting the gas flow at the upper part in the slag box; the connecting piece is mounted on the slag box and is used for connecting the slag box with the adjusting structure; the first regulating valves are distributed at the two ends of the connecting piece and used for regulating the size of the first regulating valves to control the gas flow in the upper part of the slag box, and the second regulating valves are distributed on the inner sides of the first regulating valves and used for regulating the size of the second regulating valves to control the gas flow in the upper part of the slag box; waste gas and ash in the slag box are discharged through diversion, and the temperature difference and SO2 concentration difference of the upper surface and the lower surface of glass are balanced, so that the dealkalization reaction of SO2 on the surface of a glass plate is balanced, the hydroxyl concentration on the glass plate is maintained, warping caused by tin permeation of the lower surface of the glass is resisted, the structural difference of the upper surface and the lower surface of the glass is maintained, warping of an original sheet is reduced, and the glass quality is improved.

The invention discloses a method for removing sodium and potassium in red mud by using a ferric sulfate solution, and belongs to the technical field of industrial solid waste treatment and recycling. The method for removing the sodium and the potassium in the red mud by using the ferric sulfate solution comprises the following steps: mixing the ferric sulfate solution with the red mud, carrying out dealkalization treatment, and then carrying out solid-liquid separation to obtain dealkalized red mud and dealkalized leachate, so as to complete removal of the sodium and the potassium in the red mud. Compared with a traditional acid neutralization method which directly uses inorganic acid or organic acid as a raw material, the method has the advantages that the acid in the dealkalization process comes from Fe < 3 + > hydrolysis; when H < + > is consumed in the dealkalization process, hydrolysis balance of Fe < 3 + > moves to continuously supplement H < + >, selective removal of sodium is realized in the dealkalization process, and the content of Na2O in the dealkalized red mud is 1t; 1%. The acid generated by hydrolysis can effectively dissolve sodium-containing silicate, but hardly dissolves aluminum-containing components in the red mud, so that selective dealkalization is realized.

The utility model discloses a red mud gas-liquid coupling deep dealkalization device, and belongs to the technical field of red mud dealkalization. Comprising a stirring box, a feeding pipe arranged at the top of the outer side of the stirring box, a shaft rod vertically and rotatably mounted in the middle of the interior of the stirring box, a stirring rod vertically fixed to the side edge of the shaft rod and a stirring motor fixed to the top of the stirring box and used for driving the shaft rod, and a guide groove is formed in the shaft rod in the length direction; and separation grooves communicated with the guide grooves are formed in the stirring rods in the length direction. The guide groove is formed in the shaft rod, the separation groove is formed in the stirring rod, the exhaust ports communicated with the separation groove are evenly formed in the outer side of the stirring rod, meanwhile, the guide groove is communicated with the separation groove, and the end of the air inlet pipe is communicated with the separation groove through the rotating mechanism. An air pipe does not need to be arranged in the stirring box, a solvent in the stirring box is increased, and cleaning is more convenient.

The application discloses a strain with a red mud dealkalization function and application thereof, and the classification name of the BRY1 strain is Acinetobacter baumannii Acinetobacter baumannii , the preservation number of which is GDMCC No 66371, the preservation date is May 22, 2025, and the preservation unit is Guangdong Microbial Culture Collection Center. The BRY1 strain provided by the application has strong alkali resistance and high acid production capacity, and can quickly and effectively neutralize alkaline substances in red mud. The BRY1 strain is obtained by being separated and screened from a specific environment, i.e., a red mud storage yard, and has good adaptability and dealkalization specificity to the red mud environment.

The application belongs to the technical field of solid waste resource utilization, and particularly relates to a red mud-based multifunctional water treatment agent and a preparation method thereof. The method comprises the steps of red mud dealkalization, drying and crushing, acid dissolution reaction, pH regulation, function enhancement and slow-release carrier forming, etc. By introducing modified polyacrylamide functional additives and compound flocculants, the removal capacity of the treatment agent for heavy metal ions, organic pollutants and high-hardness ions is effectively improved. A sodium alginate-polyvinyl alcohol ion cross-linking slow-release system is used to realize the combination of long-acting release and broad-spectrum purification functions. Compared with the prior art, the method not only realizes the resource utilization of red mud waste, but also has the advantages of structural stability, strong adaptability, high treatment efficiency and the like.

The invention provides a method for dealkalizing red mud and desulfurizing in an aluminum oxide production process, and belongs to the field of comprehensive treatment of red mud. The method comprises the following steps: drying and crushing high-alkali red mud to obtain pretreated high-alkali red mud; mixing the pretreated high-alkali red mud with a calcium nitrate solution to obtain a first mixed solution; heating the first mixed solution in a water bath to perform a dealkalization reaction of the high-alkali red mud in the mixed solution to obtain a second mixed solution; carrying out solid-liquid separation on the second mixed solution while the second mixed solution is hot to obtain dealkalized red mud and a sodium nitrate-containing solution; and adding the sodium nitrate-containing solution into the high-sulphoaluminate solution for desulfurization reaction to obtain a low-sulphoaluminate solution. According to the present invention, the high-alkali red mud is adopted to modify and is combined with the calcium nitrate reaction to produce the efficient desulfurization agent for removing the low-valence sulfur in the alumina system, such that the use cost of sodium nitrate is reduced, the alkali in the red mud is recycled, and the large-scale consumption of the red mud is promoted so as to achieve the efficient desulfurization effect while the red mud is dealkalized; desulfurization is realized by cooperating with an alumina production process.

The invention provides low-saline-alkali slag engineering soil and a preparation method thereof. The method comprises the following steps: pumping water-containing alkaline residues into a slurry A stirring device, introducing CO2-containing alkaline residue lime kiln flue gas, and adding a dealkalization auxiliary agent to prepare dealkalized alkaline residue slurry A; meanwhile, in another stirring device B, auxiliary materials and water are mixed, and auxiliary slurry B is obtained; next, pumping the dealkalized alkaline residue slurry A and the auxiliary slurry B into a mixed slurry tank, adding an ionic solubilizer, and further stirring to form mixed slurry; and finally, conveying the mixed slurry to a plate and frame dehydrator, and carrying out filter pressing dehydration treatment to obtain a filter cake, namely the low-alkali low-saline-alkali slag engineering soil. The low-alkali and low-salt-alkali slag engineering soil has excellent early strength and rapid hardening characteristics, meanwhile, the dealkalization and desalination efficiency of the alkali slag is remarkably improved, and a solution is provided for recycling, reduction, harmless treatment and high-value utilization of the alkali slag.

The invention belongs to the technical field of environmental protection and solid waste recycling, and particularly relates to a passivated fully dealkalized red mud catalyst and a preparation method thereof. According to the method, the amount of added accurate dealkalization acid is limited through an acid amount formula, a weak acid reaction environment is created, only alkaline substances contained in the red mud are limited to participate in a neutralization reaction by controlling parameters such as passivation dosage, liquid-solid ratio, stirring time and temperature, water-soluble alkali salt is generated, then the alkali salt is separated and discharged in a filtering mode, and the water-soluble alkali salt is obtained. And preparing a dealkalized red mud filter cake. In the whole reaction process, Fe2O3, TiO2 and other metal oxide components are passivated by the passivator due to a weak acid environment, and the oxidation effect is basically completely retained in the dealkalized red mud filter cake. The alkali content of the dealkalized red mud obtained by the technical method is zero, and the iron content is increased. The red mud prepared through high-temperature calcination can be used as an iron-based denitration catalyst, and the flue gas denitration rate is high.

The present application provides a porous calcium silicate and a preparation method thereof, comprising the steps of: providing a high modulus water glass solution as a silicon source, providing lime milk as a calcium source, adding dodecyl trimethylammonium chloride and betaine citric acid, obtaining a mixed solution, heating the mixed solution, reacting with lime synthesis to obtain a calcium silicate slurry; filtering the calcium silicate slurry to obtain a crude calcium silicate filter cake; adding water to pulp to obtain a slurry, heating the slurry, adding a dealkalizing agent, maintaining the temperature at 90-95°C, dealkalizing reaction, generating a dealkalized calcium silicate slurry; solid-liquid separation of the alkali-containing calcium silicate slurry to obtain a calcium silicate filter cake, drying, breaking up, and obtaining a finished porous calcium silicate. The present application significantly improves the specific surface area of ​​porous calcium silicate.