Low-energy-consumption preparation method and application of hydrogen-based mineral phase conversion iron tailing ultrafine powder

Abstract

The invention provides a low-energy-consumption preparation method and application of hydrogen-based mineral phase conversion iron tailing ultrafine powder, and belongs to the technical field of iron tailing recycling. By adopting a synergistic preparation process of microbial desilicication solubilization, chemical catalytic thickening, microwave drying activation and mechanical grinding, the composition, surface state and microstructure of the hydrogen-based mineral phase conversion iron tailings are subjected to echelon action, so that the particle defects of the hydrogen-based mineral phase conversion iron tailings are aggravated, the structure is crispy, the cracking tendency is improved, the potential activity of particles is further improved, and the service life of the hydrogen-based mineral phase conversion iron tailings is prolonged. And the difficulty and the energy consumption of particle size refining are reduced, and a low-energy-consumption and high-utilization-rate recycling technical approach is provided for conversion of the hydrogen-based ore phase into the iron tailings. The prepared hydrogen-based mineral phase conversion iron tailing ultrafine powder has excellent activity, can be used as a substitute of common active mixed materials, admixtures, active raw materials and the like, is widely applied to cement-based products or non-cement-based products, and has remarkable economic benefits and technical benefits.

Description

A low-energy preparation method and application of hydrogen-based mineral phase transformation iron tailings ultrafine powder Technical Field

[0001] This invention relates to the field of iron tailings recycling technology, specifically to a low-energy preparation method and application of hydrogen-based mineral phase conversion iron tailings ultrafine powder. Background Technology

[0002] Hydrogen-based mineral phase transformation technology is a high-efficiency, low-consumption separation technology developed in recent years by the iron and steel smelting industry for complex and difficult-to-process iron ores. This technology significantly improves the iron beneficiation rate while also inducing phase transformation in inert substances such as quartz in the ore, and altering the surface morphology and potential reactivity of iron tailings particles. Simultaneously, due to the increased efficiency of magnetic separation, the tailings particles produced after iron ore crushing and beneficiation are relatively large compared to active admixtures such as fly ash, but much smaller than the fine aggregate gradation range. Therefore, they are unsuitable for direct application as fine aggregate in cement concrete materials, nor can they be directly used as admixtures in cement-based materials. Using them solely as an inert filler is uneconomical and cannot meet the disposal requirements.

[0003] Existing conventional disposal methods, including backfilling, stockpiling, and low-level blending for road or civil engineering projects, fail to fully utilize the economic and application potential of iron tailings from hydrogen-based mineral phase conversion. While mechanical, thermal activation, and chemical activation techniques have significant reactivity-enhancing effects, their scientific logic is insufficient. Therefore, to address the need for reuse of hydrogen-based mineral phase conversion iron tailings, more advanced preparation technologies and higher regeneration efficiency are urgently required.

[0004] Hydrogen-based mineral phase transformation has a multidimensional effect on the molecular structure of iron ore. During magnetic separation, more iron-phase materials are separated, increasing the mass loss of individual ore particles. This effectively reduces the iron content in iron tailings while increasing the surface roughness and the number and depth of microcracks. This provides a material basis for a novel processing method for hydrogen-based mineral phase transformation iron tailings. Compared to traditional processes that rely on low-activity use, chemical activation, or thermal activation after grinding, pre-processing techniques that structurally degrade and modify the minerals of hydrogen-based mineral phase transformation iron tailings particles before grinding can more effectively utilize the changes in the molecular structure of iron tailings during the hydrogen-based mineral phase transformation process. This reduces the technical difficulty and energy consumption of particle refinement, producing highly active ultrafine powder and improving product quality and processing efficiency. The obtained hydrogen-based mineral phase transformation iron tailings ultrafine powder can serve as a substitute for commonly used active mixing materials and admixtures, effectively alleviating the pressure of solid waste emissions from mines and improving the environmental friendliness and sustainable development of the construction and building materials industries.

[0005] Existing technologies for preparing iron tailings powder primarily target ordinary iron tailings, and suffer from problems such as high energy consumption and low utilization rates. The compatibility of these technologies with hydrogen-based mineral phase conversion iron tailings is not ideal. For example, Chinese patent CN202210284866.4 provides a comprehensive utilization method for high-silica iron tailings, utilizing a mixed microbial community with iron-dissolving and desilication functions to bioleach the high-silica iron tailings, recovering iron a second time. The leachate can be recycled, and it can effectively improve the chemical reactivity of the leaching residue, which can be used as an active admixture in the preparation of iron tailings-based cementitious materials. This technology only targets the microbial leaching of ordinary iron tailings particles, primarily aiming to increase the iron extraction rate while also considering improving the activity of the residue. The microbial community used differs significantly from that of this invention, and it does not involve microwave drying and activation technology, but rather complex chemical processes such as acid washing. Its residues will inevitably affect the practical application of the tailings powder.

[0006] For example, the literature "Research Progress of Grinding Aids in Iron Ore Grinding" (Zhou Guishi et al., Mining Research and Development, 2025, Vol. 45 (09), pp. 241-250) introduces relevant grinding aids and their grinding mechanisms for pyrite, chalcopyrite, and iron tailings. This literature only describes the grinding process under grinding aid conditions and does not involve technical means such as microbial treatment and microwave drying activation. Moreover, the grinding aids used in this literature are quite different from those in this invention. The master's thesis "The Influence of Grinding Aids on Grinding and Separation of Fine-Grained Embedded Magnetite" (Zhu Zhaoqiang, Wuhan University of Science and Technology, September 2022) uses sodium tripolyphosphate, sodium hexametaphosphate, and water glass as grinding aids to study their influence on the grinding effect of a certain fine-grained embedded magnetite. Combined with the relevant test results such as slurry viscosity, surface potential, particle surface adsorption characteristics, particle morphology, and magnetic concentrate index, the mechanism of action of grinding aids in improving the grinding effect of magnetite, reducing grinding energy consumption, and improving the magnetic concentrate index is explained. This literature also simply studies the mechanical grinding of magnetite using grinding aids, without involving other activation methods. The literature "Influence of Grinding Aids on the Grinding Effect of Iron Tailings and the Hydration Performance of Mixed Cement" (Liu Bao et al., *Journal of Southeast University*, 2022, Issue 52(05)) uses triethanolamine and triisopropanolamine as grinding aids for iron tailings and explores their effects on improving the activity of iron tailings and their hydration process. This literature also focuses on ordinary iron tailings, and its activation process does not involve microbial treatment or microwave activation. The literature "Study on the Coupling Effect of Multidimensional Excitation on the Activation of Silicon-Rich Iron Tailings" (Li Xiao et al., *New Building Materials*, 2022, Issue 49(06), 1-5) uses multidimensional excitation methods of mechanical-thermal-chemical excitation and mechanical-microwave-chemical excitation to activate iron tailings, and compares and analyzes the 28-day hardened body of iron tailings and iron tailings-cement system under different excitation methods. The technical methods described in this literature do not involve microbial solubilization activation and are also a combination of multiple conventional activation methods. The master's thesis, "Research on Synergistic Activation of Iron Tailings Based on Microbial Treatment" (Shi Tiantian, Shenyang Jianzhu University, June 2025), employs a synergistic activation method combining microbial treatment, mechanical activation, and chemical activation to achieve solubilization and activation of inert components such as silica in iron tailings. This paper identifies an effective activation regime and analyzes the mechanism by which iron tailings affect mortar properties. However, this paper focuses on ordinary iron tailings, primarily utilizing activating enzymes produced by the secondary reproduction of Bacillus subtilis to increase the solubility of silicon in the quartz phase, thereby accelerating the hydration reaction rate of silicon through other means. This differs significantly from the technology involved in this invention.

[0007] In summary, among the existing iron tailings powder preparation technologies mentioned above:

[0008] (1) It mainly targets ordinary iron tailings, while the mineral composition, particle microstructure, and element valence state of hydrogen-based mineral phase transformation iron tailings are quite different from those of ordinary iron tailings. The traditional process of simply grinding by mechanical force to reduce particle size cannot fully explore the potential activity of hydrogen-based mineral phase transformation iron tailings, and it consumes a lot of energy.

[0009] (2) The selection of grinding aids is mainly aimed at ordinary iron tailings, and most of the grinding aid mechanisms refer to cement and other systems. There is a lack of research on grinding aids for the particle characteristics of iron tailings transformed from hydrogen-based mineral phases.

[0010] (3) The precursor or follow-up chemical activation mainly acts on glassy silicon and aluminum materials, and has no significant effect on stable minerals such as quartz. Therefore, under the condition that the apparent activity of hydrogen-based mineral phase transformation iron tailings is low, the chemical activation effect is not prominent, and its environmental friendliness is poor.

[0011] (4) The microwave activation process adopted is not reasonable enough. It has little effect on stable silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra, and there is a lack of research on the microwave process mechanism for the characteristics of hydrogen-based mineral phase transformation iron tailings.

[0012] The existing powder preparation technologies mentioned above are all designed for ordinary iron tailings. Most employ single or combined processes involving traditional mechanical, thermal, and chemical activation, resulting in high energy consumption, low environmental friendliness, and significant equipment investment. These technologies are simplistic and lack practical effectiveness in preparing powders from hydrogen-based mineral phase conversion iron tailings. Furthermore, the resulting iron tailings powders clearly do not meet the performance requirements of highly active auxiliary materials. The activity potential of hydrogen-based mineral phase conversion iron tailings differs significantly from that of ordinary iron tailings, including differences in surface functional groups, valence states of exposed ions, types of surface valence bonds, and unit cell parameters. Therefore, the technical logic for preparing highly active ultrafine powders from hydrogen-based mineral phase conversion iron tailings is much stronger. Existing research on the preparation of ultrafine powders from hydrogen-based mineral phase conversion iron tailings is almost nonexistent, and no relevant technical methods have emerged.

[0013] Therefore, under the new circumstances where the construction industry is vigorously promoting the application of low-grade raw materials while advocating for the long-term planning of buildings, hydrogen-based mineral phase conversion iron tailings, as a new type of solid waste material, urgently needs to develop efficient resource utilization technologies to achieve its low-carbon disposal and high-quality regeneration applications. Summary of the Invention

[0014] To address the shortcomings of existing technologies, this invention provides a low-energy-consumption preparation method and application of ultrafine powder from hydrogen-based mineral phase conversion iron tailings. This invention employs microbial desilication and solubilization technology, using specific bacterial strains to disrupt the stability of silicon-oxygen tetrahedra in hydrogen-based mineral phase conversion iron tailings, increasing particle surface defects. Then, specific chemical substances are added in a slurry state for catalysis and thickening treatment, achieving effective molecular dispersion, reducing particle surface energy, and removing live microorganisms. Further drying and activation under microwave conditions further destroy microbial cells, releasing soluble silicon, while simultaneously expanding internal particle defects and increasing the number of free radicals. Ultimately, this reduces the structural strength of hydrogen-based mineral phase conversion iron tailings particles, making them easier to shrink under mechanical force, thus achieving a low-energy-consumption preparation technology path for ultrafine powder from hydrogen-based mineral phase conversion iron tailings.

[0015] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0016] In a first aspect, the present invention provides a low-energy-consumption preparation method for ultrafine powder of hydrogen-based mineral phase conversion iron tailings, comprising the following steps:

[0017] Hydrogen-based mineral phase conversion iron tailings particles were mixed evenly with water, and the pH value was adjusted to 6.6-7.0 with citric acid. Microbial culture medium was added, and polymyxin Bacillus was inoculated for microbial treatment to obtain slurry A. Sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate were added to slurry A for chemical treatment, and then microwave drying and activation treatment was performed to obtain powder B. Powder B was ground to obtain hydrogen-based mineral phase conversion iron tailings ultrafine powder.

[0018] To address the problems of low potential utilization rate of hydrogen-based mineral phase conversion iron tailings, difficulty in preparing high-quality products, and high energy consumption, this invention employs a synergistic approach of microbial desilication and solubilization treatment, chemical catalytic thickening treatment, microwave drying and activation treatment, and mechanical grinding treatment to prepare ultrafine powder of hydrogen-based mineral phase conversion iron tailings.

[0019] First, this invention uses citric acid (other acids are detrimental to the secondary reproduction of the strain) to adjust the initial pH of the slurry to a range suitable for the secondary reproduction of microorganisms. This has excellent biological adaptability to *Bacillus polymyxa* (e.g., *Bacillus polymyxa* DSM36) and will not adversely affect microbial reproduction. The suitable pH for the survival of *Bacillus polymyxa* is 6.6-7.4. The initial pH of the slurry set in this invention is 6.6-7.0 because acidic conditions can catalyze the silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra contained in the hydrogen-based mineral phase transformation iron tailings, inducing a secondary transformation of their metastable molecular structure, which is beneficial to reducing their surface energy and thus increasing their tendency to open surface cracks. The microbial culture medium (beef extract, peptone, NaCl) used in this invention is suitable for the growth and reproduction of *Bacillus polymyxa*, while the required silicon source is provided by the hydrogen-based mineral phase transformation iron tailings. The secondary reproduction cycle of *Bacillus polymyxa* is 1 day. Based on its nutrient consumption rate, a prescribed amount of microbial culture medium needs to be replenished every 3 days to meet the secondary reproduction needs of *Bacillus polymyxa*. This invention employs microbial desilication and solubilization technology, ensuring that the strain is evenly distributed on the surface of each particle. Extracellular activating enzymes and organic acids produced by the strain's metabolism cause the removal of stable silicon elements from the surface to the interior of the hydrogen-based mineral phase conversion iron tailings particles. Because the surface energy of hydrogen-based mineral phase conversion iron tailings particles is significantly lower than that of ordinary iron tailings, and they have higher surface roughness, more potential micro-cracks, and a higher tendency for unsaturated silicon-oxygen bonds, the silicon elements contained within are more easily dissociated into the liquid phase under the action of *Bacillus polymyxa*. This significantly increases the porosity of the surface of the hydrogen-based mineral phase conversion iron tailings particles, the extent to which pores extend inward, and the size of microcracks. It also significantly increases the surface defects of the hydrogen-based mineral phase conversion iron tailings particles, reduces surface energy, and consequently reduces the hardness and structural stability of the hydrogen-based mineral phase conversion iron tailings particles, making them brittle and defective, thus reducing the difficulty of further fracture.

[0020] Furthermore, the specific surface area of ​​the hydrogen-based mineral phase transformation iron tailings ultrafine powder is 500-550 m². 2 / kg.

[0021] Furthermore, the weight ratio of the hydrogen-based mineral phase conversion iron tailings particles to water is 1:(1-1.5).

[0022] Furthermore, based on the volume of slurry A, the inoculation amount of the polymyxin Bacillus is 5000-50000 CFU / L.

[0023] Furthermore, based on the volume of slurry A, the raw materials of the microbial culture medium include 1.5-2.5 g / L beef extract, 2.5-3.5 g / L peptone, and 4.5-5.5 g / L NaCl.

[0024] Furthermore, based on the volume of the slurry A, the raw materials of the microbial culture medium include 2.0 g / L beef extract, 3.0 g / L peptone, and 5.0 g / L NaCl.

[0025] Furthermore, during the microbial treatment, the slurry temperature is maintained at 20-25℃, the stirring speed is 30-50 r / min, and the treatment cycle is 6-12 days; during the microbial treatment, the microbial culture medium is replenished as needed according to the rate of nutrient consumption.

[0026] Furthermore, during the microbial treatment, supplementary culture medium is added to the microbial culture system every 3 days. The supplementary culture medium ingredients, based on the volume of the microbial culture system, include 0.4-0.8 g / L beef extract, 0.6-1.0 g / L peptone, and 1-2 g / L NaCl.

[0027] Furthermore, based on the volume of the microbial culture system, the supplementary culture medium ingredients included 0.6 g / L beef extract, 0.8 g / L peptone, and 1.5 g / L NaCl.

[0028] Subsequently, the present invention adds specific chemical substances (sodium lauryl ester, adipic acid, polyethylene glycol, triethanolamine and diethyl phosphate) to slurry A obtained by microbial desilication and solubilization treatment for chemical catalysis and thickening treatment. After the chemical substances are dissolved, they can fully and uniformly contact the surface of the hydrogen-based mineral phase conversion iron tailings particles and penetrate into the cracks inside the particles. Sodium laurate can effectively reduce the viscosity of hydrogen-based mineral phase conversion iron tailings slurry, improve dispersibility, enhance the adsorption of other chemical substances on the particle surface, promote the penetration of internal microcracks, and hinder crack recovery. After adsorbing onto the surface of hydrogen-based mineral phase conversion iron tailings particles, adipic acid can increase the active sites of newly generated silicon substances after microbial solubilization and activation, further reducing particle surface energy and increasing pulverization tendency. After adsorbing onto the surface of hydrogen-based mineral phase conversion iron tailings particles, polyethylene glycol and triethanolamine can improve particle dispersibility and reduce agglomeration. Diethyl phosphate can further reduce particle hardness by undergoing molecular cross-linking with the surface of hydrogen-based mineral phase conversion iron tailings particles through physical adsorption. Thus, after microorganisms have microscopically defected the particles, chemical catalysis and thickening effects exacerbate the instability of crystal structure and mineral structure.

[0029] Furthermore, the amounts of sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate added are 0.1‰-0.14‰, 0.04‰-0.08‰, 1.2‰-1.6‰, 1.0‰-1.8‰, and 0.1‰-0.2‰ of the weight of the iron tailings particles from the hydrogen-based mineral phase conversion, respectively. After the sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate are added to the slurry, and after a certain period of chemical catalytic thickening, they can also inactivate microorganisms, destroy the cell walls of microorganisms, and allow the silicon elements absorbed inside them to re-enter the liquid phase in a soluble form.

[0030] Furthermore, during the chemical treatment, the mixture is first stirred at a speed of 30-50 r / min, with each cycle consisting of 10 min of stirring followed by 30 min of settling. After 3-5 cycles, stirring is stopped until the process is complete. The total time for the chemical treatment is 1-2 days.

[0031] The slurry, after chemical catalytic thickening, is then dried and activated under microwave conditions. The residual iron in the hydrogen-based mineral phase conversion iron tailings and the water in the slurry generate high-frequency vibrations under microwave action, converting electromagnetic energy into heat energy. This process not only evaporates moisture and reduces the water content of the hydrogen-based mineral phase conversion iron tailings, but also completely inactivates any remaining microorganisms, causing soluble silicon in the liquid phase to precipitate completely and disperse in the solid particles or adhere to the surface of other solid particles. Simultaneously, apart from iron, the main components of the hydrogen-based mineral phase conversion iron tailings do not exhibit electromagnetic effects. Therefore, only the iron within the particles generates high-frequency vibrations and temperature increases. Since the main component of the hydrogen-based mineral phase conversion iron tailings is an inorganic non-metallic mineral phase, which is a poor conductor of heat, this results in an uneven temperature field within individual particles. Temperature stress is generated near the iron, inducing the formation of new microcracks and the propagation of existing cracks within the particles, exacerbating defects and bringing them closer to the critical size. This causes the particle structure of hydrogen-based mineral phase transformation iron tailings to be further weakened after microbial desilication and solubilization and chemical catalytic thickening, allowing it to break down further under less external force, thus facilitating particle refinement.

[0032] Furthermore, the microwave frequency used during the microwave drying and activation process is 22000±500 MHz.

[0033] Furthermore, the moisture content of the powder B does not exceed 2%.

[0034] Finally, the present invention mechanically grinds the hydrogen-based mineral phase transformation iron tailings, which have undergone microbial desilication and solubilization treatment, chemical catalytic thickening treatment, and microwave drying and activation treatment, to a specific surface area of ​​500-550 m². 2 / kg, yielding ultrafine powder of hydrogen-based mineral phase conversion iron tailings. In this process, sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate, which are uniformly mixed with the hydrogen-based mineral phase conversion iron tailings particles during the slurry stage, provide a grinding aid effect during mechanical grinding. The unsaturated tendency of silicon-oxygen bonds in the hydrogen-based mineral phase conversion iron tailings is significantly enhanced, making it easier to directionally adsorb specific functional groups, and the particle surface becomes rougher, exacerbating internal defects. Simultaneously, due to the relative homogeneity of the solution, the uniformity of the distribution of each chemical substance on the surface of the solid particles far exceeds the effect of simultaneous addition during grinding, thus better exerting its grinding aid effect. During mechanical grinding, sodium laurate lubricates the particle surface, increases the tendency for crack propagation, and exacerbates mineral lattice distortion and chemical bond breakage. Adipic acid lowers the particle surface energy, increasing its refining efficiency under mechanical force. Polyethylene glycol and triethanolamine, due to their polyhydroxyl molecular structure, exhibit sustained adsorption on inert mineral surfaces. Through the stepwise adsorption of hydroxyl groups on their molecular chains, they ensure particle dispersibility, especially after particle refinement, thus preventing excessive agglomeration of hydrogen-based mineral-phase conversion iron tailings particles below the micrometer scale. Diethyl phosphate further reduces the hardness of hydrogen-based mineral-phase conversion iron tailings particles through physical cross-linking, increasing their resistance to damage under external forces. All of these factors significantly reduce grinding energy consumption, improve grinding efficiency, lower preparation costs, and enhance the potential activity of particles, thereby improving the quality of ultrafine powder.

[0035] In a second aspect, the present invention provides ultrafine powder of hydrogen-based mineral phase conversion iron tailings prepared by the aforementioned preparation method.

[0036] A third aspect of the present invention provides applications of the hydrogen-based mineral phase conversion iron tailings ultrafine powder, including but not limited to its use as a mineral admixture or active raw material in cement-based or non-cement-based products. For example, the hydrogen-based mineral phase conversion iron tailings ultrafine powder is used as a mineral admixture in the preparation of cement-based products, or as an active raw material in the preparation of non-cement-based products.

[0037] Compared with the prior art, the advantages of the present invention are:

[0038] 1. This invention employs microbial desilication and solubilization treatment, chemical catalytic thickening treatment, and microwave drying and activation treatment to pretreat hydrogen-based mineral phase conversion iron tailings before mechanical grinding. During the pretreating process, the hydrogen-based mineral phase conversion iron tailings particles become brittle due to surface desilication and roughening, the initiation of new internal cracks, the expansion of existing cracks, and a decrease in surface hardness. Furthermore, the silicon-containing substances form tiny particles during solubilization and precipitation. The uniform dispersion of chemical substances such as sodium laurate in the liquid phase is significantly higher than in the solid phase, and the grinding-aiding effect is exacerbated during the chemical catalytic thickening treatment cycle. This allows the hydrogen-based mineral phase conversion iron tailings to be ultra-finely ground under low energy consumption conditions during mechanical grinding. The process principle and technical logic are strong, and the synergistic effect is high, providing a new technical approach for the resource utilization of hydrogen-based mineral phase conversion iron tailings.

[0039] 2. The microbial desilication and solubilization process adopted in this invention allows for the continuous generation of microorganisms through secondary reproduction. The process requires only necessary stirring and nutrient replenishment. The catalytic thickening stage also requires only 3-5 cycles of intermittent stirring, resulting in low energy consumption. The chemical substances used in the chemical catalytic thickening stage have good dispersibility, leading to a more significant grinding aid effect and effectively reducing grinding time, thereby lowering energy consumption. After the precursor treatment, the hydrogen-based mineral phase conversion iron tailings particles are significantly softened and, to some extent, finer, thus significantly reducing the grinding time required in the ultrafine grinding process. All of these factors contribute to an overall energy consumption far lower than that of grinding processes under traditional grinding aid conditions.

[0040] 3. The microbial desilication and solubilization treatment, chemical catalytic thickening treatment, and microwave drying and activation treatment adopted in this invention improve the grinding efficiency of hydrogen-based mineral phase conversion iron tailings. At the same time, they enhance the potential activity of the iron tailings through microbial solubilization and activation, secondary induction of metastable structure, enhancement of silicon-oxygen bond unsaturation tendency, and crystal structure instability. Together with particle ultrafineness, the prepared hydrogen-based mineral phase conversion iron tailings ultrafine powder has excellent activity, and can be widely used in various cement, concrete and other materials and products, with significant economic and technical benefits.

[0041] 4. This invention has low requirements for equipment conditions, and existing equipment conditions can meet the requirements. There is no need to upgrade complex mechanical equipment. The process has strong adaptability, reliability and universality. It effectively solves the problem of high-value-added resource utilization of iron tailings from hydrogen-based mineral phase conversion, and does not generate a lot of noise and environmental pollution.

[0042] In summary, compared to the preparation methods mentioned in the background art, this invention employs the synergistic effect of microbial desilication and solubilization, chemical catalytic thickening, microwave drying and activation, and mechanical grinding to perform a tiered process on hydrogen-based mineral phase conversion iron tailings. The process exhibits strong adaptability, reliability, and universality, effectively solving the problem of high-value-added resource utilization of hydrogen-based mineral phase conversion iron tailings, without generating significant noise and with low energy consumption. The polymyxa bacteria used for microbial activation are harmless to humans and beneficial to the environment. They are killed during the chemical catalytic thickening and microwave drying and activation stages of the hydrogen-based mineral phase conversion iron tailings slurry, transforming into active substances without excess emissions or other environmental pollution. Detailed Implementation

[0043] To enable those skilled in the art to clearly and completely understand the technical solution of the present invention, the present invention will be further described in detail below with reference to embodiments. Obviously, the embodiments described herein are only for explaining the present invention and are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] This invention provides a low-energy-consumption method for preparing ultrafine powder from hydrogen-based mineral phase conversion iron tailings, comprising the following steps:

[0045] Hydrogen-based mineral phase conversion iron tailings particles were uniformly mixed with water, and the pH was adjusted to 6.6-7.0 with citric acid. Citrate ions showed good compatibility with the subsequently inoculated *Bacillus polymyxa* strain and would not adversely affect its activation. Microbial culture medium was added, and *Bacillus polymyxa* was inoculated for microbial treatment to obtain slurry A. Sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate were added to slurry A for chemical treatment, followed by microwave drying and activation to obtain powder B. Powder B was then milled to a specific surface area of ​​500-550 m² / g. 2 / kg, to obtain hydrogen-based mineral phase transformation iron tailings ultrafine powder.

[0046] In some examples, the weight ratio of the hydrogen-based mineral phase conversion iron tailings particles to water is 1:(1-1.5).

[0047] In some examples, the inoculum amount of the polymyxin Bacillus is 5000-50000 CFU / L, based on the volume of slurry A.

[0048] In some examples, the raw materials of the microbial culture medium, based on the volume of the slurry A, include 1.5-2.5 g / L beef extract, 2.5-3.5 g / L peptone, and 4.5-5.5 g / L NaCl.

[0049] In some examples, during the microbial treatment, the slurry temperature is maintained at 20-25°C, the stirring speed is 30-50 r / min, and the treatment cycle is 6-12 days. Depending on the nutrient consumption rate, supplementary culture medium is added to the microbial culture system every 3 days. The supplementary culture medium, based on the volume of the microbial culture system, includes 0.4-0.8 g / L beef extract, 0.6-1.0 g / L peptone, and 1-2 g / L NaCl.

[0050] In some examples, the amounts of sodium lauryl ester, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate added are 0.1‰-0.14‰, 0.04‰-0.08‰, 1.2‰-1.6‰, 1.0‰-1.8‰, and 0.1‰-0.2‰ of the weight of the iron tailings particles from the hydrogen-based mineral phase conversion, respectively.

[0051] In some examples, the chemical treatment process involves stirring at a speed of 30-50 r / min, with each cycle consisting of 10 min of stirring followed by 30 min of settling. After 3-5 cycles, stirring is stopped until thickening is complete, and the total time for the chemical treatment process is 1-2 days.

[0052] In some examples, the microwave frequency used in the microwave drying and activation process is 22000±500 MHz, and the moisture content of powder B obtained after drying and activation does not exceed 2%.

[0053] Based on the mineral composition and morphological characteristics of silicon, aluminum, iron, calcium, etc., contained in hydrogen-based mineral phase conversion iron tailings, this invention employs a process of microbial desilication activation, chemical catalytic thickening, microwave drying activation, followed by mechanical grinding to prepare ultrafine powder of hydrogen-based mineral phase conversion iron tailings. This preparation method fully utilizes the changes in crystal structure, chemical bond energy, and surface energy of iron tailings after hydrogen-based mineral phase conversion. By employing pre-treatment measures to induce defects, soften, activate, and uniformly adsorb the hydrogen-based mineral phase conversion iron tailings particles, it enables grinding to a specified fineness with lower energy consumption, overcoming the major technical challenges of high energy consumption and low efficiency in the ultrafine processing of hydrogen-based mineral phase conversion iron tailings.

[0054] The method provided by this invention does not have specific requirements on the particle size of the selected hydrogen-based mineral phase conversion iron tailings, and can directly use raw materials discharged from the mine.

[0055] This invention first employs a specific bacterial strain, *Bacillus polymyxa*, to solubilize, activate, and structurally defect-inducing the silicon-containing components of hydrogen-based mineral phase conversion iron tailings. Before use, the *Bacillus polymyxa* bacterial culture is stored at a constant temperature of 20-30°C, which can be achieved through a constant-temperature water bath or by using an air conditioning system. Before use, it should be examined under an optical microscope to confirm that the strain is growing well and free from contamination or variation. 5000-50000 CFU of *Bacillus polymyxa* is added to each liter of slurry A. This inoculum size ensures optimal microbial activity and treatment efficiency for hydrogen-based mineral phase conversion iron tailings. If the bacterial dosage is too low, the utilization efficiency of the bacterial culture decreases, and an eutrophic environment is easily formed, resulting in nutrient residue. If the bacterial dosage is too high, excessive consumption during secondary generation of the strain in the stirred container will lead to increased nutrient consumption, while the actual microbial solubilization and activation efficiency remains insignificant, resulting in waste.

[0056] During the microbial desilication and solubilization treatment, the slurry temperature and stirring blade speed should be controlled, and an appropriate amount of microbial culture medium should be added to the stirring container to provide sufficient nutrients for the reproduction of the strains. If the microbial treatment cycle is too short, it will not be conducive to the solubilization and activation effect of the strains, and the effect on inducing defects in iron tailings particles from hydrogen-based mineral phase transformation will not be significant; if the treatment cycle is too long, the efficiency of the strains will decrease as the difficulty of the activating enzyme penetrating into the particles increases.

[0057] After microbial desilication and solubilization treatment, specific chemical substances—sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate—are used to chemically catalyze and thicken the slurry of hydrogen-based mineral phase conversion iron tailings particles. Experimental studies have shown that among similar substances containing the same functional groups, the combined use of sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate exhibits the best comprehensive effect. This significantly reduces the viscosity of the hydrogen-based mineral phase conversion iron tailings slurry, improves dispersibility, enhances surface adsorption and internal microcrack propagation, increases active sites, reduces particle surface energy, reduces pulverization tendency, and decreases particle hardness. Simultaneously, the uniform distribution of these chemical substances after solidification also provides efficient grinding aid during subsequent mechanical grinding. After the catalytic thickening process, the slurry consistency and water content are reduced.

[0058] After chemical catalytic thickening, the slurry is dried and activated using microwaves. Microwave drying and activation inactivate the *Bacillus polymyxa* strain, causing its cell walls to rupture and shrink. This allows absorbed soluble silicon, aluminum, and calcium elements to escape the cell walls and re-enter the liquid phase, increasing the ion concentration in the liquid phase. As the slurry's moisture content decreases, silicon, aluminum, and calcium elements precipitate out of the liquid phase, but they can still dissolve upon re-addition of water, thus enhancing the reactivity of the hydrogen-based mineral phase conversion iron tailings. The microwave drying process controls the moisture content of the hydrogen-based mineral phase conversion iron tailings to ≤2%, at which point the particles are less likely to agglomerate, which is beneficial for subsequent mechanical grinding. The preferred microwave frequency is 22000±500 MHz, which achieves high drying efficiency but can also exacerbate the instability of the already damaged molecular structure.

[0059] Finally, this invention uses equipment such as vertical mills or ball mills to grind the hydrogen-based mineral phase transformation iron tailings powder B to the required fineness (specific surface area 500-550 m²) in a single process. 2 / kg). During mechanical grinding, the defects, hardness, and brittleness of hydrogen-based mineral phase conversion iron tailings particles, which have undergone microbial desilication and solubilization treatment, chemical catalytic thickening treatment, and microwave drying and activation treatment in the early stage, are aggravated. Under the grinding-aiding effect of chemicals such as sodium laurate, the refining efficiency is significantly improved, so the energy consumption required for grinding is relatively low. Based on the composition, morphology, and effects of previous processes on hydrogen-based mineral phase conversion iron tailings, the addition of sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate in proportion is the preferred solution to improve the efficiency of mechanical grinding and has an activating effect on the potential activity of hydrogen-based mineral phase conversion iron tailings. It should be noted that further increasing the particle fineness is also possible, but due to the increased elasticity of the particles, the energy consumption is too high, and the negative impact of excessively fine particles on their application, such as water demand, is not worthwhile.

[0060] In the following specific implementation cases, the model parameters and procurement sources of the raw materials used are shown in Table 1.

[0061] Table 1: Model parameters and procurement sources of raw materials used in the following examples

[0062]

[0063] Example 1

[0064] This embodiment provides an ultrafine powder of hydrogen-based mineral phase transformation iron tailings, the preparation steps of which are as follows:

[0065] S1. Hydrogen-based mineral phase conversion iron tailings particles and water are mixed evenly in a slurry tank at a weight ratio of 1:1, and the pH is adjusted to 6.8 with citric acid. Then, microbial culture medium is added, and DSM36 polymyxin Bacillus is inoculated for microbial treatment to obtain slurry A. Based on the volume of slurry A, the microbial culture medium contains 2.0 g / L beef extract, 3.0 g / L peptone, and 5.0 g / L NaCl, and the inoculation amount of DSM36 polymyxin Bacillus is 30,000 CFU / L. During the microbial treatment, the temperature in the slurry tank is maintained at 20℃, the blade stirring speed is continuously 40 r / min, the microbial treatment time is 9 days, and every 3 days, 0.6 g / L beef extract, 0.8 g / L peptone, and 1.5 g / L NaCl are added to the slurry tank.

[0066] S2. Taking the weight of the hydrogen-based mineral phase transformation iron tailings particles in the slurry tank as 100%, 0.12‰ sodium laurate, 0.06‰ adipic acid, 1.4‰ polyethylene glycol, 1.5‰ triethanolamine, and 0.1‰ diethyl phosphate were added to the slurry tank for chemical treatment. Then, microwave drying and activation were carried out at 22000±500 MHz until the powder moisture content was 1.5%, resulting in powder B. During the chemical treatment, the blades in the slurry tank were first stirred at a speed of 40 r / min, with a cycle of 10 min of stirring followed by 30 min of settling. After 5 cycles, stirring was stopped. The total chemical treatment time was 1 day.

[0067] S3. Grind powder B to obtain hydrogen-based mineral phase transformation iron tailings ultrafine powder.

[0068] Example 2

[0069] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this embodiment are basically the same as those in Example 1, except that: in step S1, the inoculum amount of DSM36 polymyxin Bacillus is 50,000 CFU / L.

[0070] Example 3

[0071] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this embodiment are basically the same as those in Example 1. The difference is that in step S1, during the microbial treatment, the temperature in the slurry tank is maintained at 25°C, the blade stirring speed is 30 r / min, and the microbial treatment time is 12 days.

[0072] Example 4

[0073] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this embodiment are basically the same as those in Example 1, except that in step S2, with the weight of the hydrogen-based mineral phase conversion iron tailings particles in the slurry tank as 100%, 0.14‰ sodium laurate, 0.08‰ adipic acid, 1.6‰ polyethylene glycol, 1.8‰ triethanolamine, and 0.2‰ diethyl phosphate are added to the slurry tank for chemical treatment.

[0074] Example 5

[0075] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this embodiment are basically the same as those in Example 1, except that the total chemical treatment time in step S2 is 2 days.

[0076] Comparative Example 1

[0077] The iron tailings ultrafine powder provided in this comparative example has the same preparation steps as in Example 1, except that an equal amount of ordinary iron tailings particles are used to replace the hydrogen-based mineral phase transformation iron tailings particles.

[0078] Comparative Example 2

[0079] This comparative example provides an ultrafine powder of hydrogen-based mineral phase conversion iron tailings, the preparation steps of which are as follows: the hydrogen-based mineral phase conversion iron tailings particles are ground to obtain the ultrafine powder of hydrogen-based mineral phase conversion iron tailings.

[0080] Comparative Example 3

[0081] This comparative example provides an ultrafine powder of hydrogen-based mineral phase transformation iron tailings, the preparation steps of which are as follows:

[0082] S1. Hydrogen-based mineral phase conversion iron tailings particles and water are mixed evenly in a slurry tank at a weight ratio of 1:1, and the pH is adjusted to 6.8 with citric acid. Then, microbial culture medium is added, and *Bacillus subtilis* bio-51767 is inoculated for microbial treatment to obtain slurry A. According to the volumetric dosage of slurry A, the microbial culture medium contains 0.5 g / L MgSO4·7H2O, 0.1 g / L CaSO4·2H2O, 1.8 g / L Na2HPO4, 0.005 g / L FeCl3, and 5 g / L glucose. The inoculation amount of *Bacillus subtilis* bio-51767 is 30000 CFU / L. During the microbial treatment, the temperature in the slurry tank is maintained at 20℃, the blade stirring speed is continuously 40 r / min, the microbial treatment time is 9 days, and 0.15 g / L MgSO4·7H2O and 0.04 g / L CaSO4·2H2O are added to the slurry tank every 3 days. g / L, Na2HPO4 0.54 g / L, FeCl3 0.002 g / L, glucose 1.5 g / L.

[0083] S2. Taking the weight of the hydrogen-based mineral phase transformation iron tailings particles in the slurry tank as 100%, 0.12‰ sodium laurate, 0.06‰ adipic acid, 1.4‰ polyethylene glycol, 1.5‰ triethanolamine, and 0.1‰ diethyl phosphate were added to the slurry tank for chemical treatment. Then, microwave drying and activation were carried out at 22000±500 MHz until the powder moisture content was 1.5%, resulting in powder B. During the chemical treatment, the blades in the slurry tank were first stirred at a speed of 40 r / min, with a cycle of 10 min of stirring followed by 30 min of settling. After 5 cycles, stirring was stopped. The total chemical treatment time was 1 day.

[0084] S3. Grind powder B to obtain hydrogen-based mineral phase transformation iron tailings ultrafine powder.

[0085] Comparative Example 4

[0086] This comparative example provides an ultrafine powder of hydrogen-based mineral phase transformation iron tailings, the preparation steps of which are as follows:

[0087] S1. Hydrogen-based mineral phase conversion iron tailings particles and water are mixed evenly in a slurry tank at a weight ratio of 1:1, and the pH is adjusted to 6.8 with citric acid. Then, microbial culture medium is added, and DSM36 polymyxin Bacillus is inoculated for microbial treatment (Slurry A). According to the volumetric dosage of Slurry A, the microbial culture medium contains 2.0 g / L beef extract, 3.0 g / L peptone, and 5.0 g / L NaCl, and the inoculation amount of DSM36 polymyxin Bacillus is 30,000 CFU / L. During the microbial treatment, the temperature in the slurry tank is maintained at 20℃, the blade stirring speed is continuously 40 r / min, the microbial treatment time is 9 days, and every 3 days, 0.6 g / L beef extract, 0.8 g / L peptone, and 1.5 g / L NaCl are added to the slurry tank.

[0088] S2. Microwave drying and activation of slurry A at 22000±500 MHz until the powder moisture content is 1.5%, thus obtaining powder B.

[0089] S3. Using 100% by weight of hydrogen-based mineral phase conversion iron tailings particles, add 0.12‰ sodium lauryl ester, 0.06‰ adipic acid, 1.4‰ polyethylene glycol, 1.5‰ triethanolamine, and 0.1‰ diethyl phosphate to powder B and grind to obtain hydrogen-based mineral phase conversion iron tailings ultrafine powder.

[0090] Comparative Example 5

[0091] This comparative example provides an ultrafine powder of hydrogen-based mineral phase transformation iron tailings, the preparation steps of which are as follows:

[0092] S1. Hydrogen-based mineral phase conversion iron tailings particles and water are mixed evenly in a slurry tank at a weight ratio of 1:1, and the pH is adjusted to 6.8 with citric acid. Then, microbial culture medium is added, and DSM36 polymyxin Bacillus is inoculated for microbial treatment (Slurry A). According to the volumetric dosage of Slurry A, the microbial culture medium contains 2.0 g / L beef extract, 3.0 g / L peptone, and 5.0 g / L NaCl, and the inoculation amount of DSM36 polymyxin Bacillus is 30,000 CFU / L. During the microbial treatment, the temperature in the slurry tank is maintained at 20℃, the blade stirring speed is continuously 40 r / min, the microbial treatment time is 9 days, and every 3 days, 0.6 g / L beef extract, 0.8 g / L peptone, and 1.5 g / L NaCl are added to the slurry tank.

[0093] S2. Taking the weight of the hydrogen-based mineral phase conversion iron tailings particles in the slurry tank as 100%, 0.12‰ sodium laurate, 0.06‰ adipic acid, 1.4‰ polyethylene glycol, 1.5‰ triethanolamine, and 0.1‰ diethyl phosphate were added to the slurry tank for chemical treatment. Then, the powder was dried under electric heating at 105℃±5℃ until the moisture content of the powder was 1.5%, thus obtaining powder B. During the chemical treatment, the blades in the slurry tank were first stirred at a speed of 40 r / min, with a cycle of stirring for 10 min and standing for 30 min. After 5 cycles, stirring was stopped. The total chemical treatment time was 1 day.

[0094] S3. Grind powder B to obtain hydrogen-based mineral phase transformation iron tailings ultrafine powder.

[0095] Comparative Example 6

[0096] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this comparative example are basically the same as those in Example 1, except that in step S2, an equal amount of sodium stearate is used to replace sodium laurate.

[0097] Comparative Example 7

[0098] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this comparative example are basically the same as those in Example 1, except that in step S2, an equal amount of acrylic acid is used to replace adipic acid.

[0099] Comparative Example 8

[0100] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this comparative example are basically the same as those in Example 1, except that in step S2, an equal amount of ethylene glycol is used to replace polyethylene glycol.

[0101] Comparative Example 9

[0102] The preparation steps of the hydrogen-based mineral phase conversion iron tailings ultrafine powder provided in this comparative example are basically the same as those in Example 1, except that in step S2, an equal amount of sodium tripolyphosphate is used to replace diethyl phosphate.

[0103] Experimental Example: Performance Evaluation of Ultrafine Powders Prepared in Examples 1-5 and Comparative Examples 1-9

[0104] 1. Performance Testing Methods

[0105] (1) 28-day activity index test

[0106] The 28-day activity index test for the final activated hydrogen-based mineral phase conversion iron tailings (i.e., hydrogen-based mineral phase conversion iron tailings powder K3) was determined according to the method requirements in Appendix D of GB / T 1596-2005 "Fly Ash for Cement and Concrete".

[0107] (2) Fineness test

[0108] The determination was performed according to the requirements of GB / T 8074-2021 "Determination of Specific Surface Area of ​​Cement - Blaine Method".

[0109] 2. Test Results

[0110] The results of the activity index, fineness, and grinding time after 28 days are shown in Table 2 below.

[0111] Table 2: Performance evaluation results of the ultrafine powders prepared in Examples 1-5 and Comparative Examples 1-9

[0112]

[0113] Based on the test results in Table 2 above, and by comparing Examples 1 and 2, it can be seen that, within the scope defined by this invention, changing the inoculum amount of Bacillus polymyxa 36 will affect the difficulty and energy consumption (reflected in grinding time and specific surface area) of preparing ultrafine powder from hydrogen-based mineral phase conversion iron tailings, as well as the 28-day activity index.

[0114] Comparing Examples 1 and 3, it can be seen that changing the slurry temperature, blade stirring speed, and treatment time during the microbial treatment stage will have a certain impact on the difficulty and energy consumption (reflected in grinding time and specific surface area) of preparing ultrafine powder from hydrogen-based mineral phase conversion iron tailings, but will not have a significant impact on the 28-day activity index.

[0115] Comparing Examples 1 and 4, it can be seen that changing the amount of chemicals such as sodium laurylate will affect the difficulty and energy consumption (reflected in grinding time, specific surface area) of preparing ultrafine powder of hydrogen-based mineral phase conversion iron tailings, as well as the 28-day activity index.

[0116] Comparing Examples 1 and 5, it can be seen that changing the total chemical treatment time will have a certain impact on the difficulty and energy consumption (reflected in grinding time, specific surface area) of preparing ultrafine powder from hydrogen-based mineral phase conversion iron tailings, as well as the 28-day activity index.

[0117] Based on the above comparison, the hydrogen-based mineral phase conversion iron tailings ultrafine powders of Examples 1-5 provided by the present invention still have superior performance.

[0118] By comparing Example 1 and Comparative Example 1, it can be seen that the preparation method of the present invention also has a certain effect on ordinary iron tailings. However, in terms of energy consumption and 28-day activity index, the performance of ordinary iron tailings ultrafine powder is far lower than that of hydrogen-based mineral phase conversion iron tailings ultrafine powder within the same fineness range. This indicates that the present invention is specifically designed for hydrogen-based mineral phase conversion iron tailings and has significant differences from the processing of ordinary iron tailings.

[0119] By comparing Example 1 and Comparative Example 2, it can be seen that the microbial treatment, chemical treatment, and microwave drying and activation process before mechanical grinding involved in the present invention has technical logic and significant effect. Compared with the direct mechanical grinding of hydrogen-based mineral phase conversion iron tailings, the method of the present invention can significantly reduce the energy consumption for preparing ultrafine powder of hydrogen-based mineral phase conversion iron tailings and improve its activity.

[0120] Comparative Examples 1 and 3 show that replacing DSM36 polymyxin Bacillus with Bacillus bio-51767 (and changing the culture medium to one suitable for secondary propagation) significantly and adversely affects the energy consumption and 28-day activity index in the preparation of ultrafine powder from hydrogen-based mineral phase conversion iron tailings. Although the desilication properties of Bacillus bio-51767 can also have some effect on the preparation of ultrafine powder from hydrogen-based mineral phase conversion iron tailings, the effect is far less than that of Bacillus DSM36. This indicates that the composition of Bacillus DSM36 and the microbial culture medium is irreplaceable in the method of this invention.

[0121] By comparing Example 1 and Comparative Example 4, it can be seen that if chemical substances such as sodium lauryl are added during the mechanical grinding stage, it will have a significant adverse effect on the energy consumption and 28-day activity index of the preparation of hydrogen-based mineral phase conversion iron tailings ultrafine powder. This is because they act directly on the grinding process without undergoing pre-thickening, which cannot guarantee effective dispersion, and their respective induction, occupancy, and viscosity reduction effects cannot be effectively exerted.

[0122] By comparing Example 1 and Comparative Example 5, it can be seen that electric heating drying cannot achieve the same technical effect as microwave drying activation in this invention. This is because the actual temperature of electric heating is insufficient to cause a change in mineral composition and does not have the effect of microwaves intensifying molecular structure instability. This indicates that the microwave drying activation used in this invention has a significant impact on the preparation of ultrafine powder from hydrogen-based mineral phase transformation iron tailings.

[0123] By comparing Example 1 and Comparative Example 6, it can be seen that replacing sodium laurate with an equal amount of sodium stearate will have a negative impact on the difficulty of preparing ultrafine powder of hydrogen-based mineral phase conversion iron tailings and energy consumption (reflected in grinding time, specific surface area), as well as the 28-day activity index.

[0124] By comparing Example 1 and Comparative Example 7, it can be seen that replacing adipic acid with an equal amount of acrylic acid will have a certain impact on the difficulty and energy consumption (reflected in grinding time and specific surface area) of preparing ultrafine powder of hydrogen-based mineral phase conversion iron tailings, and the negative impact on its 28-day activity index is more significant.

[0125] By comparing Example 1 and Comparative Example 8, it can be seen that replacing polyethylene glycol with an equal amount of ethylene glycol has little effect on the early grinding effect of hydrogen-based mineral phase conversion iron tailings, but has a significant impact on the difficulty and energy consumption of the further particle refinement stage (reflected in the grinding time and specific surface area of ​​the final expected specific surface area) and the 28-day activity index.

[0126] Comparing Example 1 and Comparative Example 9, it can be seen that replacing diethyl phosphate with an equal amount of sodium tripolyphosphate will have a significant negative impact on the difficulty of preparing ultrafine powder of hydrogen-based mineral phase conversion iron tailings and energy consumption (reflected in grinding time, specific surface area), as well as the 28-day activity index.

[0127] In summary, this invention employs a synergistic process of microbial desilication and solubilization, chemical catalytic thickening, microwave drying and activation, and mechanical grinding to progressively affect the composition, surface state, and microstructure of hydrogen-based mineral-phase conversion iron tailings. This process intensifies particle defects, weakens the structure, and increases the tendency to fracture, thereby reducing the difficulty of particle size refinement and energy consumption. This provides a low-energy, high-utilization resource recovery technology for hydrogen-based mineral-phase conversion iron tailings. Specifically, in the microbial desilication and solubilization stage, specific bacterial species disrupt the stability of silicon-oxygen tetrahedra in the tailings, increasing surface defects. In the chemical catalytic thickening stage, the incorporation of specific chemical substances effectively disperses molecules, reduces particle surface energy, and removes living microorganisms. Microwave drying and activation further destroy microbial cells, releasing soluble silicon and expanding internal particle defects, increasing the number of free radicals. Ultimately, this reduces the structural strength of the hydrogen-based mineral-phase conversion iron tailings particles, making them easier to reduce in size under mechanical force. The hydrogen-based mineral phase transformation iron tailings ultrafine powder prepared by this invention has excellent activity and can be used as a substitute for commonly used active admixtures, additives, and active raw materials. It can be widely used in cement-based or non-cement-based products, with significant economic and technical benefits.

[0128] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A low-energy-consumption preparation method for ultrafine powder from hydrogen-based mineral phase transformation iron tailings, characterized in that, Includes the following steps: Hydrogen-based mineral phase conversion iron tailings particles were mixed evenly with water, and the pH value was adjusted to 6.6-7.0 with citric acid. Microbial culture medium was added, and polymyxin Bacillus was inoculated for microbial treatment to obtain slurry A. Sodium laurate, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate were added to slurry A for chemical treatment, and then microwave drying and activation treatment was performed to obtain powder B. Powder B was ground to obtain hydrogen-based mineral phase conversion iron tailings ultrafine powder.

2. The low-energy preparation method of hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 1, characterized in that, The specific surface area of ​​the hydrogen-based mineral phase conversion iron tailings ultrafine powder is 500-550 m². 2 / kg.

3. The low-energy preparation method of hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 1, characterized in that, Based on the volume of slurry A, the inoculation amount of the polymyxin Bacillus is 5000-50000 CFU / L.

4. The low-energy preparation method of hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 3, characterized in that, Based on the volume of slurry A, the raw materials of the microbial culture medium include 1.5-2.5 g / L beef extract, 2.5-3.5 g / L peptone, and 4.5-5.5 g / L NaCl.

5. The low-energy preparation method of hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 4, characterized in that, During the microbial treatment, the slurry temperature is maintained at 20-25℃, the stirring speed is 30-50 r / min, and the treatment cycle is 6-12 days. During the microbial treatment, the microbial culture medium is replenished as needed according to the rate of nutrient consumption.

6. The low-energy preparation method of hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 1, characterized in that, The amounts of sodium lauryl ester, adipic acid, polyethylene glycol, triethanolamine, and diethyl phosphate added are 0.1‰-0.14‰, 0.04‰-0.08‰, 1.2‰-1.6‰, 1.0‰-1.8‰, and 0.1‰-0.2‰ of the weight of the iron tailings particles from the hydrogen-based mineral phase conversion, respectively.

7. The low-energy preparation method of hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 1, characterized in that, During the chemical treatment, the mixture is first stirred at a speed of 30-50 r / min, with each cycle consisting of 10 min of stirring followed by 30 min of settling. After 3-5 cycles, stirring is stopped until the process is complete. The total time for the chemical treatment is 1-2 days.

8. The low-energy-consumption preparation method of hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 1, characterized in that, The microwave frequency used during the microwave drying and activation process is 22000±500 MHz.

9. Ultrafine powder of hydrogen-based mineral phase conversion iron tailings prepared by the preparation method according to any one of claims 1-8.

10. The application of the hydrogen-based mineral phase transformation iron tailings ultrafine powder according to claim 9, characterized in that, The applications include, but are not limited to, using the hydrogen-based mineral phase conversion iron tailings ultrafine powder as a mineral admixture or active raw material to prepare cement-based or non-cement-based products.

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