Siliceous refractory material based on silica tailings and preparation method thereof

Abstract

The invention relates to a siliceous refractory material based on silica tailings and a preparation method thereof, and the preparation method comprises the following steps: cleaning original silica tailings to obtain cleaned tailings; and the washed tailings are subjected to size grading screening, the screened washed tailings are sorted, and tailings particles with the Fe2O3 content not exceeding 0.3% are obtained. And the tailing particles are crushed and ground according to the particle size, and the crushed and ground tailing particles are subjected to quality detection to obtain the silica tailing raw material meeting the set standard. The preparation method comprises the following steps: putting 70-80% of a silica tailing raw material and 20-30% of an additive into a mixing mill, and fully premixing to obtain a premixed sample, wherein the mass of the silica tailing raw material accounts for 70-80% of the total mass of the premixed sample; feeding silica tailing raw materials with different particle size grades and the premixed sample into a mixer according to a set proportion, and fully mixing to obtain a first mixture; and selecting a sample from the first mixture according to a preset proportion, and carrying out quality detection on the sample to obtain the siliceous refractory material with a quality detection result meeting a set index.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, and in particular to a siliceous refractory material based on silica tailings and its preparation method. Background Technology

[0002] Silica (quartz sand / rock) is an important industrial mineral, widely used in glass, ceramics, casting, metallurgy, chemicals (ferrosilicon, organosilicon), construction, and electronics (photovoltaics, semiconductors). During mining and processing (crushing, screening, washing, flotation, magnetic separation, etc.), to obtain concentrates meeting specific industrial grades (such as high-purity quartz sand), a large amount of low-grade or impurity-containing waste rock, debris, and fine-grained minerals are inevitably generated. Tailings are a direct byproduct of large-scale silica production, with a huge and continuously growing output. While primarily composed of silica, they contain impurities that were not completely separated from the original ore or introduced during processing (such as feldspar, mica, clay minerals, iron oxides, titanium minerals, etc.) as well as residual beneficiation reagents (such as flotation collectors and depressants). Tailings are mostly fine-grained or ultrafine-grained (mud-like) materials, and their physical properties are unstable when stockpiled (easily liquefied, highly fluid), causing environmental pollution. Furthermore, large-scale stockpiling requires the acquisition of large amounts of land, damaging the surface ecosystem. Dry tailings easily generate dust containing harmful components (such as heavy metals and silica dust), polluting the atmosphere and endangering human health.

[0003] Silica tailings are solid waste discharged by ore processing plants under specific economic and technical conditions after grinding ore and selecting "useful components." In other words, they are the solid waste remaining after the ore has been processed to obtain concentrate. Generally, they are solid mining waste formed from tailings slurry discharged from ore processing plants after natural dewatering. They are a major component of industrial solid waste, containing a certain amount of useful metals and minerals, and can be considered a "composite" silicate, carbonate, and other mineral material. They are characterized by fine particle size, large quantity, low cost, and high usability. The accumulation of silica tailings not only pollutes the environment but also wastes resources.

[0004] Silica in silica tailings can be used as a raw material for siliceous refractories. However, directly using untreated silica tailings to produce siliceous refractories can easily lead to a comprehensive deterioration in key performance indicators such as refractoriness, volume stability, strength, thermal shock resistance, and erosion resistance of the final product due to its high impurity content, unstable composition and particle size, and undesirable mineral composition. Furthermore, the final product quality fluctuates greatly, the scrap rate is high, the lifespan in high-temperature kilns is short, there are significant safety hazards, and the overall cost is actually higher. Summary of the Invention

[0005] Therefore, it is necessary to address the aforementioned technical problems by providing a silica-based siliceous refractory material and its preparation method that can ensure the quality of products made from silica tailings.

[0006] The first aspect of this invention provides a method for preparing a siliceous refractory material based on silica tailings, comprising: The raw silica tailings are washed to remove clay minerals, soluble salts and light organic impurities, resulting in washed tailings. The washed tailings are subjected to particle size classification and screening, and the screened washed tailings are sorted to obtain tailings particles with Fe2O3 content not exceeding 0.3%. The tailings particles are crushed and ground according to their particle size, and the crushed and ground tailings particles are subjected to quality testing to obtain silica tailings raw materials that meet the set standards. 70-80% of the silica tailings raw material, which accounts for 70-30% of the total mass of the premix, is placed in a mixer and fully premixed with 20-30% of the additives to obtain a premixed sample. The silica tailings raw materials of different particle sizes and the premixed sample are fed into a mixer according to a set ratio and mixed thoroughly to obtain a first mixture. Samples are extracted from the first mixture according to a preset ratio, and the samples are subjected to quality testing to obtain siliceous refractory materials whose quality test results meet the set indicators.

[0007] In one embodiment, the washing of the raw silica tailings to remove clay minerals, soluble salts, and light organic impurities to obtain washed tailings includes: Using washing water with a pH of 6.5-7.5, and with a volume ratio of 2-3:1 between the washing water and the original silica tailings, the original silica tailings are thoroughly washed in a drum-type sand washing machine at a speed of 15-20 rpm to obtain the washed tailings. The original silica tailings have a moisture content of 15-30%, the washed tailings have a moisture content of no more than 8%, and the washed tailings contain less than 0.5% clay minerals.

[0008] In one embodiment, the step of particle size classification and screening of the washed tailings, and sorting the screened washed tailings to obtain tailings particles with an Fe2O3 content of no more than 0.3%, includes: The washed tailings are screened by a five-stage screening device to separate coarse particles with a diameter greater than 10 mm, retain washed tailings particles with a diameter range of 0.01-5 mm, and remove mud particles with a diameter less than 0.01 mm. The vibrating screen amplitude of the five-stage screening equipment is 2-3mm, and the screening efficiency exceeds 90%.

[0009] In one embodiment, the step of particle size classification and screening of the washed tailings, and sorting the screened washed tailings to obtain tailings particles with an Fe2O3 content of no more than 0.3%, further includes: The washed tailings particles are manually sorted using a belt conveyor to remove foreign minerals and mechanical impurities, and iron minerals, titanium minerals, and colored gangue are removed using a CCD color sorter.

[0010] In one embodiment, the step of crushing and grinding the tailings particles according to their particle size, and then performing quality testing on the crushed and ground tailings particles to obtain silica tailings raw materials that meet the set standards, includes: The tailings particles with a diameter of 3-5mm are crushed by a jaw crusher and an impact crusher. The discharge port gap of the jaw crusher is 10mm, and the output particle size of the impact crusher is 3-5mm. Tailings particles with a diameter of 0.1-3 mm are ground by a vertical roller mill with a roller pressure of 50 MPa and a discharge particle size range of 0.1-3 mm. Tailings particles with a diameter not exceeding 0.01 mm are also ground by an air jet mill.

[0011] In one embodiment, the step of crushing and grinding the tailings particles according to their particle size, and then performing quality testing on the crushed and ground tailings particles to obtain silica tailings raw materials that meet the set standards, further includes: The purity of SiO2 in the crushed and ground tailings particles was determined by XRF spectroscopy, the Fe2O3 content was determined by o-phenanthroline spectrophotometry, the particle size distribution was determined by laser particle size analyzer, and the moisture content was determined by oven weight loss method. The silica tailings raw material that meets the set standards shall have a SiO2 purity of not less than 92wt%, an Fe2O3 content of not more than 0.3wt%, a particle size error of not more than 5%, and a moisture content of not more than 0.5%.

[0012] In one embodiment, the additive consists of a sintering aid and a moisture-proofing agent, and the silica tailings raw material, which accounts for 70-80% of the total mass of the premix, is silica tailings raw material with a particle size of no more than 0.01 mm. The mixer is a double planetary mixer, with the low-speed paddle speed set to 25-35 rpm and the high-speed paddle speed set to 1000-1200 rpm, and the premixing time is 20±2 min.

[0013] In one embodiment, the silica tailings raw materials of different particle sizes and the premixed sample are fed into a mixer according to a set ratio and thoroughly mixed to obtain a first mixture, comprising: Add 35-40% by mass of silica tailings with a particle size of 3-5 mm and 28-35% by mass of silica tailings with a particle size of 1-3 mm into the mixer and stir for 5-10 minutes. Then add 18-24% by mass of silica tailings with a particle size of 0.1-1 mm and stir for 10-15 minutes to obtain a second mixture. Add 8-15% of a premixed sample by mass to the second mixture and stir for 15-20 minutes to obtain the first mixture.

[0014] In one embodiment, the proportion of particles with a diameter less than 0.01 mm in the silica refractory material whose quality test results meet the set indicators is 10-20%, and the mass proportion of B2O3 is in the range of 0.8-1.2%.

[0015] The second aspect of the present invention provides a silica-based refractory material, which is prepared by the method for preparing silica-based refractory materials based on silica tailings as described in any one of the first aspects.

[0016] The aforementioned silica-based refractory material and its preparation method utilize silica tailings through a series of processes including sorting, washing, drying, crushing, grinding, and quality testing to reuse the silica tailings as raw materials for refractory materials. In the batching stage, multi-stage gradation optimization technology is employed to screen aggregates, granules, fine powders, and ultrafine powders of different particle sizes from the silica tailings. This multi-stage gradation optimization achieves functional stratification of skeleton, filler, and binder through particle size gradient design, improving the tap density, hot strength, and impermeability of the refractory material. Furthermore, by adding a certain amount of sintering aids B4C and LiF, a B2O3-Li2O liquid phase can be formed at 1300 ℃, accelerating particle sintering. Simultaneously, calcium stearate and nano-silica act as anti-hygroscopic agents, effectively inhibiting the tailings' moisture absorption and agglomeration. This invention, by reusing siliceous tailings, can solve the long-term environmental impact of open-air stockpiling of siliceous tailings. On the other hand, it can also reduce the raw material cost of refractory material preparation and ensure the quality of products made from silica tailings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A schematic flowchart illustrating the preparation method of silica-based refractory materials based on silica tailings provided by the present invention. Figure 2 This is a schematic diagram of the tailings treatment process in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the process for generating siliceous refractory materials in a specific embodiment of the present invention; Figure 4 A schematic diagram of a multi-level gradation process is provided in a specific embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this specification are for illustrative purposes only and do not represent the only possible implementation.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0024] The following is combined with Figures 1-4 The present invention describes a silica-based refractory material based on silica tailings and its preparation method.

[0025] like Figure 1 As shown, in one embodiment, a method for preparing a silica-based refractory material based on silica tailings includes the following steps: Step S110: The original silica tailings are washed to remove clay minerals, soluble salts and light organic impurities, and the washed tailings are obtained.

[0026] Specifically, washing water with a pH of 6.5-7.5 is used, and the original silica tailings are thoroughly washed in a drum-type sand washing machine at a speed of 15-20 rpm, with a volume ratio of washing water to original silica tailings of 2-3:1, to obtain clean tailings.

[0027] The original silica tailings have a moisture content of 15-30%, the washed tailings have a moisture content of no more than 8%, and the clay mineral content in the washed tailings is less than 0.5%.

[0028] Step S120: The washed tailings are subjected to particle size classification and screening, and the screened washed tailings are sorted to obtain tailings particles with Fe2O3 content not exceeding 0.3%.

[0029] Specifically, the washed tailings are screened using a five-stage screening system to separate coarse particles larger than 10mm, retaining particles in the 0.01-5mm size range, and removing mud particles smaller than 0.01mm. The washed tailings particles are then manually sorted using a belt conveyor to remove foreign minerals and mechanical impurities. A CCD color sorter is used to remove iron minerals, titanium minerals, and colored gangue from the washed tailings particles.

[0030] Among them, the vibration amplitude of the five-stage screening equipment is 2-3mm, and the screening efficiency exceeds 90%.

[0031] Step S130: The tailings particles are crushed and ground according to their particle size, and the quality of the crushed and ground tailings particles is tested to obtain silica tailings raw materials that meet the set standards.

[0032] Specifically, tailings particles with a diameter of 3-5 mm are crushed using jaw crushers and impact crushers. The jaw crusher has a discharge opening gap of 10 mm, and the impact crusher outputs a finished particle size range of 3-5 mm. Tailings particles with a diameter of 0.1-3 mm are milled using a vertical roller mill with a roller pressure of 50 MPa, and the output particle size range is 0.1-3 mm. Tailings particles with a diameter not exceeding 0.01 mm are also ground using an air jet mill. XRF spectroscopy is used to detect the SiO2 purity of the crushed and ground tailings particles. The o-phenanthroline spectrophotometry method is used to detect the Fe2O3 content of the crushed and ground tailings particles. A laser particle size analyzer is used to detect the particle size distribution of the crushed and ground tailings particles. Finally, an oven weight loss method is used to detect the moisture content of the crushed and ground tailings particles.

[0033] Among them, the silica tailings raw materials that meet the set standards have a SiO2 purity of no less than 92wt%, an Fe2O3 content of no more than 0.3wt%, a particle size error of no more than 5%, and a moisture content of no more than 0.5%.

[0034] In step S140, silica tailings raw material accounting for 70-80% of the total mass of the premix and 20-30% of the additives are placed in a mixer and fully premixed to obtain a premixed sample.

[0035] Specifically, the additives consist of sintering aids and moisture-proofing agents, and the silica tailings raw material, accounting for 70-80% of the total premixed mass, is silica tailings raw material with a particle size not exceeding 0.01 mm. The mixer is a double planetary mixer, with the low-speed paddle speed set to 25-35 rpm and the high-speed paddle speed set to 1000-1200 rpm, and the premixing time is 20±2 min.

[0036] In step S150, silica tailings raw materials of different particle sizes and premixed samples are fed into a mixer according to a set ratio and mixed thoroughly to obtain a first mixture.

[0037] Specifically, 35-40% by mass of silica tailings with a particle size of 3-5 mm and 28-35% by mass of silica tailings with a particle size of 1-3 mm are added to a mixer and stirred for 5-10 minutes. Then, 18-24% by mass of silica tailings with a particle size of 0.1-1 mm are added and stirred for 10-15 minutes to obtain a second mixture. Finally, 8-15% by mass of a premix is ​​added to the second mixture and stirred for 15-20 minutes to obtain a first mixture.

[0038] Step S160: Samples are extracted from the first mixture according to a preset ratio, and the samples are subjected to quality testing to obtain siliceous refractory materials whose quality test results meet the set indicators.

[0039] Specifically, in siliceous refractory materials whose quality test results meet the set indicators, the proportion of particles with a diameter of less than 0.01 mm is 10-20%, and the mass proportion of B2O3 is in the range of 0.8-1.2%.

[0040] The aforementioned method for preparing silica-based refractory materials using silica tailings involves a series of processes, including sorting, washing, drying, crushing, grinding, and quality testing, to reuse silica tailings as raw materials for refractory materials. In the batching stage, multi-stage gradation optimization technology is employed to screen aggregates, granules, fine powders, and ultrafine powders of different particle sizes from the silica tailings. This multi-stage gradation optimization achieves functional stratification of the skeleton, filler, and binder through particle size gradient design, improving the tap density, hot strength, and impermeability of the refractory material. Furthermore, by adding a certain amount of sintering aids B4C and LiF, a B2O3-Li2O liquid phase can be formed at 1300 ℃, accelerating particle sintering. Simultaneously, calcium stearate and nano-silica act as anti-hygroscopic agents, effectively inhibiting moisture absorption and agglomeration of the tailings. This method, by reusing siliceous tailings, can, on the one hand, solve the long-term environmental impact of open-air accumulation of siliceous tailings, and on the other hand, reduce the raw material cost of refractory material preparation and ensure the quality of products made from silica tailings.

[0041] Combination Figures 2 to 4 As shown in the specific embodiments, the silica refractory material based on silica tailings and its preparation method provided by the present invention screens out the required raw materials from silica tailings through a series of processes such as sand washing, screening, sorting, color sorting, crushing and grinding, and testing. In particular, in the grinding stage, it is necessary to grind the material into coarse particles, medium particles, fine powder, and ultrafine powder according to a multi-stage gradation process.

[0042] First, the raw silica tailings (15-30% moisture content, containing clay, organic matter, and soluble salts) undergo sand washing treatment. The goal is to remove clay minerals (kaolinite, montmorillonite, etc.) adhering to the tailings surface; dissolve soluble salts (Na+, K+, Cl-, etc.); and separate light organic impurities (residual flotation reagents, humic substances). During the sand washing process, the pH of the washing water is 6.5-7.5 (to avoid acid corrosion of silica), the water-to-sand ratio is 2-3:1, and the sand washing equipment is a drum-type sand washer with a rotation speed of 15-20 rpm. Finally, cleaned tailings (moisture content ≤8%, clay content <0.5%) are obtained.

[0043] After the sand washing process, the washed tailings are then subjected to particle size classification and screening. The purpose is to separate ultra-coarse particles (particle size > 10 mm, including gangue and waste rock); retain particles within the target particle size range (0.01-5 mm); and remove ultrafine clay (particle size < 0.01 mm, including difficult-to-separate impurities). The particle size classification and screening process uses a five-stage screen system, as shown in Table 1.

[0044] The vibrating screen of this five-stage screening equipment has an amplitude of 2-3 mm and a screening efficiency of >90%.

[0045] After particle size classification and screening, the material is manually sorted via a belt conveyor to remove large heterogeneous minerals (such as feldspar lumps and mica schist) and mechanical contaminants (metal fragments and plastic debris), with a rejection rate of not less than 95%. Simultaneously, a CCD color sorter with a recognition accuracy of 0.2 mm² and an air pressure of 0.6 MPa is used to remove iron-containing minerals (Fe₂O₃ content > 1.0%), iron / titanium-containing minerals (hematite is red, ilmenite is black), and colored gangue (chlorite, tourmaline, etc.), yielding tailings (Fe₂O₃ content ≤ 0.3%).

[0046] Subsequently, the tailings (Fe2O3 content ≤ 0.3%) were crushed and ground: Coarse particle processing (3-5 mm): Jaw crusher (discharge opening gap 10 mm) → Impact crusher (finished particle size 3-5 mm); Medium / fine particle processing (0.1-3 mm): Vertical roller mill (roller pressure 50 MPa, discharge particle size 0.1-3 mm); Ultrafine powder preparation (≤0.01 mm): air jet mill (nozzle pressure 0.8 MPa, D90≤10μm).

[0047] After crushing and grinding, quality testing (composition and particle size control) is performed. The testing items, methods, and acceptance criteria are shown in Table 2.

[0048] Handling of non-conforming products: If the composition does not meet the standard, return it to the color sorting / sand washing process; if the particle size is out of tolerance, return it to the corresponding crushing / grinding section.

[0049] Combination Figure 3 As shown, in the production of siliceous refractory materials, firstly, according to customer requirements and production processes, granules and fine powders processed from silica tailings, as well as other auxiliary materials, are selected. After the raw materials arrive at the factory, they are sampled and tested according to the corresponding quality control standards. Qualified raw materials are stored for later use. For each batch of raw materials, sampling is conducted according to GB / T 6679, with at least 5 sampling points. After mixing and reducing the sample, 1 kg of sample is retained. Sampling frequency: once every 50 tons of tailings raw materials; mandatory testing for each barrel / bag of auxiliary materials. To ensure uniform dispersion of additives, the additives and some raw materials are fully pre-mixed in a mixer for batching. The additives and some raw materials include sintering aids (B4C 1-2%, LiF 0.5-1%), moisture-proofing agents (calcium stearate 0.3-0.8%, nano-hydrophobic silica 0.1-0.5%), and gradation regulators (ultrafine powder ≤0.01mm¹⁰-15%). The ultrafine powder serves as both a raw material and an additive carrier; its high specific surface area allows it to adsorb nanoparticles. Carrier raw material: Ultrafine powder (≤0.01 mm, SiO2≥92%, moisture content≤0.3%) accounts for 70-80% of the total premix mass; Additive group: B4C + LiF + calcium stearate + nano-SiO2 accounts for 20-30% of the total premix mass; Total premix mass: 100-200 kg per batch. The premixing process adopts a double planetary mixer, with the low-speed paddle speed set at 25-35 rpm and the high-speed paddle speed set at 1000-1200 rpm, and the premixing time is 20±2 min.

[0050] In this embodiment, raw materials of different specifications are placed in corresponding silos, and their respective proportions are entered into the system according to the product process formula. For example... Figure 4As shown, using a multi-stage gradation process, adding coarse, medium, fine, and ultrafine powders in specific proportions can effectively improve the tap density, hot strength, and impermeability of refractory materials, thereby enhancing the quality of refractory products. The mixture is placed into a weighing hopper for weighing, and after weighing, it is automatically transferred to a mixer. The proportions are: coarse particles (35-40%), medium particles (28-35%), fine powder (18-24%), and a premix (including ultrafine powder, sintering aids, and moisture-proofing agents, 8-15%). First, coarse and medium particles are added and stirred for 5-10 minutes. Then, fine powder is added and stirred for 10-15 minutes. Finally, the premix is ​​added and stirred for 15-20 minutes. The sintering aids (B4C and LiF) essentially construct a cascade reaction chain of "oxidative slag formation - fluorine-boron exchange - low-melting-point eutectic" at 1250-1350 ℃, achieving: a low-viscosity (0.8-1.2 Pa·s) highly spreadable liquid phase (contact angle <10°); impurity element immobilization (K+ → potassium nepheline), mainly removing K2O impurities from the raw materials. At 1250-1350 ℃, the reaction equation is: K2O + Al2O3 + 2SiO2 → KAlSiO4, ultimately forming a potassium nepheline solid solution (stable phase) with a K+ immobilization rate >98%; and volatilization inhibition (B2O3 encapsulating LiF). This system reduces the sintering temperature of tailings-based dry materials by more than 200 ℃ and significantly improves hot strength. Calcium stearate and nano-silica added to the sample act as moisture-proofing agents to facilitate product storage.

[0051] Afterwards, the above materials are added to the mixer and mixed for a certain period of time. After mixing, a certain amount of sample is taken to test the particle size distribution, chemical composition, and physical properties, among other quality control parameters. Only finished products that meet the particle size requirements can be packaged, and only those that pass the physical property tests can be released from the warehouse. For testing, 2-3 kg of sample is taken from each ton of material. After mixing, 500 g of the sample is taken and sieved using the standard sieve method (ASTM C92) for particle size analysis. The proportion of coarse particles and ultrafine powder (<0.01 mm) should be between 10-20%, and the mass percentage of B2O3 in the chemical composition analysis (XRF) should be between 0.8-1.2%.

[0052] The following examples, exemplified by Examples 1-3, further illustrate the silica-based refractory material and its preparation method provided by the present invention: Example

[0053] (1) Sand washing (removing impurities and mud): Input material: raw silica tailings (moisture content 15-30%, containing clay, organic matter, and soluble salts); The process parameters are set as follows: water-to-sand ratio of 2:1, drum sand washing machine speed of 15 rpm; pH of washing water of 6.5 (to avoid acid dissolution of silica).

[0054] (2) Screening (particle size classification): Input material: Tailings from the previous sand washing process; The main purpose of this process is to separate ultra-coarse particles (>10 mm, including gangue and waste rock); retain the target particle size range (0.01-5 mm); and remove ultra-fine mud (<0.01 mm, including difficult-to-separate impurities).

[0055] The grading equipment in this process is a five-stage sieve device.

[0056] Key equipment control: Vibrating screen amplitude 2 mm, screening efficiency >90%.

[0057] (3) Sorting (manual pre-selection): Target impurities: large heterogeneous minerals (such as feldspar nodules, mica schist); mechanical contaminants (metal fragments, plastic debris); Operation method: Manual picking via belt conveyor.

[0058] Color sorting (photoelectric sorting): Target impurities: iron / titanium minerals (hematite is red, ilmenite is black); colored gangue (chlorite, tourmaline, etc.); Technical parameters: CCD color sorter, recognition accuracy 0.2 mm2; jet pressure 0.6 MPa, removes iron-containing minerals (Fe2O3 content > 1.0%). Output indicator: Fe2O3 content in tailings ≤ 0.3%.

[0059] (4) Crushing and grinding (fine particle size control): Coarse particle processing (3-5 mm): Jaw crusher (discharge opening gap 10 mm) → Impact crusher (finished particle size 3-5 mm); Medium / fine particle processing (0.1-3 mm): Vertical roller mill (roller pressure 50 MPa, discharge particle size 0.1-3 mm); Ultrafine powder preparation (≤0.01 mm): air jet mill (nozzle pressure 0.8 MPa, D90≤10 μm).

[0060] (5) The quality inspection (composition and particle size control) test items, methods and qualification standards are shown in the table below:

[0061] Handling of non-conforming products: Ingredients not meeting standards → Return to color sorting / sand washing process; Particle size out of tolerance → Return to the corresponding crushing / grinding section.

[0062] The production process of the produced silica refractory materials is as follows: Raw material preparation: First, based on customer requirements and production processes, select granules and fine powders from processed silica tailings, as well as other auxiliary materials. Upon arrival at the factory, raw materials are sampled and tested according to relevant quality control standards. Qualified raw materials are then stored for future use. For each batch of raw materials, sampling is conducted according to GB / T 6679, with at least 5 sampling points. After mixing and reducing the sample size, 1 kg of sample is retained. Sampling frequency: once every 50 tons of tailings raw materials; mandatory testing for every barrel / bag of auxiliary materials.

[0063] Premixing: To ensure uniform dispersion of the additives, the additives and some raw materials are fully premixed in a mixer for batching. Raw materials: 80 kg ultrafine powder (≤0.01 mm, SiO2≥92%, moisture content≤0.3%); Additive group: B4C (1 kg) + LiF (1 kg) + calcium stearate (0.5 kg) + nano SiO2 (0.5 kg). Premixing is performed using a double planetary mixer, with the low-speed paddle speed set to 25 rpm and the high-speed paddle speed set to 1000 rpm. The premixing time is 20 min.

[0064] Ingredients: Raw materials of different specifications are placed in their respective silos, and their proportions are entered into the computer system according to the product process formula. A multi-stage gradation process is used, adding coarse, medium, fine, and ultrafine powders in specific proportions to effectively improve the tap density, hot strength, and impermeability of refractory materials, thus enhancing product quality. The materials are then placed into a weighing silo for weighing, and automatically transferred to the mixer after weighing. The proportions are: coarse particles (35%), medium particles (30%), fine powder (20%), and a premix (including 15% ultrafine powder, sintering aid, and moisture-proofing agent). First, coarse and medium particles are added and stirred for 10 minutes, then fine powder is added and stirred for another 10 minutes, and finally the premix is ​​added and stirred for 15 minutes.

[0065] Mixing: The materials are fed into the mixer and mixed for 20 minutes.

[0066] Quality Inspection: After mixing, a 2kg sample is taken to test the particle size distribution, chemical composition, and physical properties, among other quality control parameters. Only finished products meeting particle size requirements can be packaged, and only those meeting physical property requirements can be released from the warehouse. For testing, 2kg of sample is taken from each ton of material. After mixing, 500g of the sample is sieved using the standard sieve method (ASTM C92). The proportion of coarse particles and ultrafine powder (<0.01 mm) should be between 10-20%. Further chemical composition analysis (XRF) should show that the mass percentage of B2O3 is between 0.8-1.2%.

[0067] Example 2: (1) Sand washing (removing impurities and mud): Input material: raw silica tailings (moisture content 15-30%, containing clay, organic matter, and soluble salts); The process parameters are set as follows: water-to-sand ratio of 2:1, drum sand washing machine speed of 15 rpm; and pH of washing water of 6.5 (to avoid acid dissolution of silica).

[0068] (2) Screening (particle size classification): Input material: Tailings from the previous sand washing process; The main purpose of this process is to separate ultra-coarse particles (>10 mm, including gangue and waste rock); retain the target particle size range (0.01-5 mm); and remove ultra-fine mud (<0.01 mm, including difficult-to-separate impurities).

[0069] The grading equipment in this process is a five-stage sieve device.

[0070] Key equipment control: Vibrating screen amplitude 2 mm, screening efficiency >90%.

[0071] (3) Sorting (manual pre-selection): Target impurities: large heterogeneous minerals (such as feldspar nodules, mica schist); mechanical contaminants (metal fragments, plastic debris); Operation method: Manual picking via belt conveyor.

[0072] Color sorting (photoelectric sorting): Target impurities: iron / titanium minerals (hematite is red, ilmenite is black); colored gangue (chlorite, tourmaline, etc.); Technical parameters: CCD color sorter, recognition accuracy 0.2 mm2; jet pressure 0.6 MPa, removes iron-containing minerals (Fe2O3 content > 1.0%).

[0073] Output indicator: Fe2O3 content in tailings ≤ 0.3%.

[0074] (4) Crushing and grinding (fine particle size control): Coarse particle processing (3-5 mm): Jaw crusher (discharge opening gap 10 mm) → Impact crusher (finished particle size 3-5 mm); Medium / fine particle processing (0.1-3 mm): Vertical roller mill (roller pressure 50 MPa, discharge particle size 0.1-3 mm); Ultrafine powder preparation (≤0.01 mm): air jet mill (nozzle pressure 0.8 MPa, D90≤10 μm).

[0075] (5) The quality inspection (composition and particle size control) test items, methods and qualification standards are shown in the table below:

[0076] Handling of non-conforming products: Ingredients not meeting standards → Return to color sorting / sand washing process; Particle size out of tolerance → Return to the corresponding crushing / grinding section.

[0077] The production process of the produced silica refractory materials is as follows: Raw material preparation: First, based on customer requirements and production processes, select granules and fine powders from processed silica tailings, as well as other auxiliary materials. Upon arrival at the factory, raw materials are sampled and tested according to relevant quality control standards. Qualified raw materials are then stored for future use. For each batch of raw materials, sampling is conducted according to GB / T 6679, with at least 5 sampling points. After mixing and reducing the sample size, 1 kg of sample is retained. Sampling frequency: once every 50 tons of tailings raw materials; mandatory testing for every barrel / bag of auxiliary materials.

[0078] Premixing: To ensure uniform dispersion of the additives, the additives and some raw materials are fully premixed in a mixer for batching. The additives and some raw materials include sintering aids (B4C 1-2%, LiF 0.5-1%), moisture absorbers (calcium stearate 0.3-0.8%, nano-hydrophobic silica 0.1-0.5%), and gradation regulators (ultrafine powder ≤0.01mm × 10-15%). The ultrafine powder serves as both a raw material and an additive carrier, its high specific surface area allowing it to adsorb nanoparticles. Carrier raw material: Ultrafine powder (≤0.01 mm, SiO2 ≥92%, moisture content ≤0.3%) accounts for 80% of the total premixed mass. Additive group: B4C + LiF + calcium stearate + nano-SiO2 accounts for 20% of the total premixed mass. Total premixed mass: 100-200 kg per batch. The premixing process uses a dual planetary mixer, with the low-speed paddle set to 25 rpm and the high-speed paddle set to 1000 rpm. The premixing time is 20 minutes.

[0079] Ingredients: Raw materials of different specifications are placed in their respective silos, and their proportions are entered into the computer system according to the product process formula. A multi-stage gradation process is used, adding coarse, medium, fine, and ultrafine powders in specific proportions to effectively improve the tap density, hot strength, and impermeability of refractory materials, thus enhancing product quality. The materials are then placed into a weighing silo for weighing, and automatically transferred to the mixer after weighing. The proportions are: coarse particles (30%), medium particles (35%), fine powder (20%), and a premix (including ultrafine powder, sintering aid, and moisture-proofing agent 15%). First, coarse and medium particles are added and stirred for 10 minutes, then fine powder is added and stirred for another 10 minutes, and finally the premix is ​​added and stirred for 15 minutes.

[0080] Mixing: The materials are fed into the mixer and mixed for 20 minutes.

[0081] Quality Inspection: After mixing, a 2kg sample is taken to test the particle size distribution, chemical composition, and physical properties, among other quality control parameters. Only finished products meeting particle size requirements can be packaged, and only those meeting physical property requirements can be released from the warehouse. For testing, 2kg of sample is taken from each ton of material. After mixing, 500g of the sample is sieved using the standard sieve method (ASTM C92). The proportion of coarse particles and ultrafine powder (<0.01 mm) should be between 10-20%. Further chemical composition analysis (XRF) should show that the mass percentage of B2O3 is between 0.8-1.2%.

[0082] Example 3: (1) Sand washing (removing impurities and mud): Input material: raw silica tailings (moisture content 15-30%, containing clay, organic matter, and soluble salts); The process parameters are set as follows: water-to-sand ratio of 2:1, drum sand washing machine speed of 15 rpm; and pH of washing water of 6.5 (to avoid acid dissolution of silica).

[0083] (2) Screening (particle size classification): Input material: Tailings from the previous sand washing process; The main purpose of this process is to separate ultra-coarse particles (>10 mm, including gangue and waste rock); retain the target particle size range (0.01-5 mm); and remove ultra-fine mud (<0.01 mm, including difficult-to-separate impurities).

[0084] The grading equipment in this process is a five-stage sieve device.

[0085] Key equipment control: Vibrating screen amplitude 2 mm, screening efficiency >90%.

[0086] (3) Sorting (manual pre-selection): Target impurities: large heterogeneous minerals (such as feldspar nodules, mica schist); mechanical contaminants (metal fragments, plastic debris); Operation method: Manual picking via belt conveyor.

[0087] Color sorting (photoelectric sorting): Target impurities: iron / titanium minerals (hematite is red, ilmenite is black); colored gangue (chlorite, tourmaline, etc.); Technical parameters: CCD color sorter, recognition accuracy 0.2 mm2; jet pressure 0.6 MPa, removes iron-containing minerals (Fe2O3 content > 1.0%).

[0088] Output indicator: Fe2O3 content in tailings ≤ 0.3%.

[0089] (4) Crushing and grinding (fine particle size control): Coarse particle processing (3-5 mm): Jaw crusher (discharge opening gap 10 mm) → Impact crusher (finished particle size 3-5 mm); Medium / fine particle processing (0.1-3 mm): Vertical roller mill (roller pressure 50 MPa, discharge particle size 0.1-3 mm); Ultrafine powder preparation (≤0.01 mm): air jet mill (nozzle pressure 0.8 MPa, D90≤10 μm).

[0090] (5) The quality inspection (composition and particle size control) test items, methods and qualification standards are shown in the table below:

[0091] Handling of non-conforming products: Ingredients not meeting standards → Return to color sorting / sand washing process; Particle size out of tolerance → Return to the corresponding crushing / grinding section.

[0092] The production process of the produced silica refractory materials is as follows: Raw material preparation: First, based on customer requirements and production processes, select granules and fine powders from processed silica tailings, as well as other auxiliary materials. Upon arrival at the factory, raw materials are sampled and tested according to relevant quality control standards. Qualified raw materials are then stored for future use. For each batch of raw materials, sampling is conducted according to GB / T 6679, with at least 5 sampling points. After mixing and reducing the sample size, 1 kg of sample is retained. Sampling frequency: once every 50 tons of tailings raw materials; mandatory testing for every barrel / bag of auxiliary materials.

[0093] Premixing: To ensure uniform dispersion of the additives, the additives and some raw materials are fully premixed in a mixer for batching. The additives and some raw materials include sintering aids (B4C 1-2%, LiF 0.5-1%), moisture absorbers (calcium stearate 0.3-0.8%, nano-hydrophobic silica 0.1-0.5%), and gradation regulators (ultrafine powder ≤0.01mm × 10-15%). The ultrafine powder serves as both a raw material and an additive carrier, its high specific surface area allowing it to adsorb nanoparticles. Carrier raw material: Ultrafine powder (≤0.01 mm, SiO2 ≥92%, moisture content ≤0.3%) accounts for 80% of the total premixed mass. Additive group: B4C + LiF + calcium stearate + nano-SiO2 accounts for 20% of the total premixed mass. Total premixed mass: 100-200 kg per batch. The premixing process uses a dual planetary mixer, with the low-speed paddle set to 25 rpm and the high-speed paddle set to 1000 rpm. The premixing time is 20 minutes.

[0094] Ingredients: Raw materials of different specifications are placed in their respective silos, and their proportions are entered into the computer system according to the product process formula. A multi-stage gradation process is used, adding coarse, medium, fine, and ultrafine powders in specific proportions to effectively improve the tap density, hot strength, and impermeability of refractory materials, thus enhancing product quality. The materials are then placed into a weighing silo for weighing, and automatically transferred to the mixer after weighing. The proportions are: coarse particles (40%), medium particles (30%), fine powder (15%), and a premix (including ultrafine powder, sintering aid, and moisture-proofing agent 15%). First, coarse and medium particles are added and stirred for 10 minutes, then fine powder is added and stirred for another 10 minutes, and finally the premix is ​​added and stirred for 15 minutes.

[0095] Mixing: The materials are fed into the mixer and mixed for 20 minutes.

[0096] Quality Inspection: After mixing, a 2kg sample is taken to test the particle size distribution, chemical composition, and physical properties, among other quality control parameters. Only finished products meeting particle size requirements can be packaged, and only those meeting physical property requirements can be released from the warehouse. For testing, 2kg of sample is taken from each ton of material. After mixing, 500g of the sample is sieved using the standard sieve method (ASTM C92). The proportion of coarse particles and ultrafine powder (<0.01 mm) should be between 10-20%. Further chemical composition analysis (XRF) should show that the mass percentage of B2O3 is between 0.8-1.2%.

[0097] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preparing a siliceous refractory material based on silica tailings, characterized in that, include: The raw silica tailings are washed to remove clay minerals, soluble salts and light organic impurities, resulting in washed tailings. The washed tailings are subjected to particle size classification and screening, and the screened washed tailings are sorted to obtain tailings particles with Fe2O3 content not exceeding 0.3%. The tailings particles are crushed and ground according to their particle size, and the crushed and ground tailings particles are subjected to quality testing to obtain silica tailings raw materials that meet the set standards. 70-80% of the silica tailings raw material, which accounts for 70-30% of the total mass of the premix, is placed in a mixer and fully premixed with 20-30% of the additives to obtain a premixed sample. The silica tailings raw materials of different particle sizes and the premixed sample are fed into a mixer according to a set ratio and mixed thoroughly to obtain a first mixture. Samples are extracted from the first mixture according to a preset ratio, and the samples are subjected to quality testing to obtain siliceous refractory materials whose quality test results meet the set indicators.

2. The method for preparing silica-based refractory materials according to claim 1, characterized in that, The process of washing the raw silica tailings to remove clay minerals, soluble salts, and light organic impurities to obtain washed tailings includes: Using washing water with a pH of 6.5-7.5, and with a volume ratio of 2-3:1 between the washing water and the original silica tailings, the original silica tailings are thoroughly washed in a drum-type sand washing machine at a speed of 15-20 rpm to obtain the washed tailings. The original silica tailings have a moisture content of 15-30%, the washed tailings have a moisture content of no more than 8%, and the washed tailings contain less than 0.5% clay minerals.

3. The method for preparing silica-based refractory materials according to claim 1, characterized in that, The process of particle size classification and screening of the washed tailings, followed by sorting of the screened tailings to obtain tailings particles with an Fe2O3 content not exceeding 0.3%, includes: The washed tailings are screened by a five-stage screening device to separate coarse particles with a diameter greater than 10 mm, retain washed tailings particles with a diameter range of 0.01-5 mm, and remove mud particles with a diameter less than 0.01 mm. The vibrating screen amplitude of the five-stage screening equipment is 2-3mm, and the screening efficiency exceeds 90%.

4. The method for preparing silica-based refractory materials according to claim 3, characterized in that, The step of particle size classification and screening of the washed tailings, and sorting the screened washed tailings to obtain tailings particles with an Fe2O3 content of no more than 0.3%, further includes: The washed tailings particles are manually sorted using a belt conveyor to remove foreign minerals and mechanical impurities, and iron minerals, titanium minerals, and colored gangue are removed using a CCD color sorter.

5. The method for preparing silica-based refractory materials according to claim 1, characterized in that, The tailings particles are crushed and ground according to particle size, and the crushed and ground tailings particles are subjected to quality testing to obtain silica tailings raw materials that meet the set standards, including: The tailings particles with a diameter of 3-5mm are crushed by a jaw crusher and an impact crusher. The discharge port gap of the jaw crusher is 10mm, and the output particle size of the impact crusher is 3-5mm. Tailings particles with a diameter of 0.1-3 mm are ground by a vertical roller mill with a roller pressure of 50 MPa and a discharge particle size range of 0.1-3 mm. Tailings particles with a diameter not exceeding 0.01 mm are also ground by an air jet mill.

6. The method for preparing silica-based refractory materials according to claim 5, characterized in that, The process of crushing and grinding the tailings particles according to their particle size, and then performing quality testing on the crushed and ground tailings particles to obtain silica tailings raw materials that meet the set standards, further includes: The purity of SiO2 in the crushed and ground tailings particles was determined by XRF spectroscopy, the Fe2O3 content was determined by o-phenanthroline spectrophotometry, the particle size distribution was determined by laser particle size analyzer, and the moisture content was determined by oven weight loss method. The silica tailings raw material that meets the set standards shall have a SiO2 purity of not less than 92wt%, an Fe2O3 content of not more than 0.3wt%, a particle size error of not more than 5%, and a moisture content of not more than 0.5%.

7. The method for preparing silica-based refractory materials according to claim 1, characterized in that, The additive consists of sintering aids and moisture-proofing agents, and the silica tailings raw material, which accounts for 70-80% of the total mass of the premix, is silica tailings raw material with a particle size not exceeding 0.01 mm. The mixer is a double planetary mixer, with the low-speed paddle speed set to 25-35 rpm and the high-speed paddle speed set to 1000-1200 rpm, and the premixing time is 20±2 min.

8. The method for preparing silica-based refractory materials according to claim 1, characterized in that, The silica tailings raw materials of different particle sizes, graded according to a set ratio, and the premixed sample are fed into a mixer and thoroughly mixed to obtain a first mixture, comprising: Add 35-40% by mass of silica tailings with a particle size of 3-5 mm and 28-35% by mass of silica tailings with a particle size of 1-3 mm into the mixer and stir for 5-10 minutes. Then add 18-24% by mass of silica tailings with a particle size of 0.1-1 mm and stir for 10-15 minutes to obtain a second mixture. Add 8-15% of a premixed sample by mass to the second mixture and stir for 15-20 minutes to obtain the first mixture.

9. The method for preparing silica-based refractory materials according to claim 1, characterized in that, The quality test results of the siliceous refractory materials that meet the set indicators have a particle size of less than 0.01 mm accounting for 10-20% and a B2O3 mass percentage in the range of 0.8-1.2%.

10. A siliceous refractory material based on silica tailings, characterized in that, It is prepared by the method for preparing silica-based refractory materials based on silica tailings as described in any one of claims 1 to 9.

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