Inorganic fibers prepared from industrial solid waste and their preparation method

Abstract

This invention provides an inorganic fiber prepared from industrial solid waste and its preparation method, belonging to the field of inorganic fiber preparation technology. In this application, the rare earth-doped low-temperature eutectic reduces the viscosity of the solid waste melt and inhibits phase separation by disrupting and stabilizing the silicon-oxygen network, creating a uniform melt environment. The carbon-coated composite nanoparticles reduce the viscosity synergistically through in-situ carbothermal reduction reaction, while using the reaction gas to clarify the melt and remove internal defects. The core-shell nanocrystals modified on the apatite surface serve as the core of the microstructure construction, inducing the formation of fine and uniform microcrystalline phases inside the fiber, thus constructing the high-strength foundation of the material. The homogenization of the low-temperature eutectic is a prerequisite for the uniform dispersion of subsequent additives. The core-shell nanocrystals construct a high-strength microcrystalline matrix, while the carbon-coated particle core is positioned at the phase interface, endowing the fiber with high toughness through a physical mechanism. The three work together to improve the comprehensive mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of inorganic fiber preparation technology, and relates to an inorganic fiber prepared from industrial solid waste and its preparation method. Background Technology

[0002] Industrial solid waste, such as steel slag and basalt tailings, is produced in enormous quantities. These wastes are rich in components such as silica, alumina, calcium oxide, and magnesium oxide, which are the basic chemical building blocks of high-performance silicate glass and ceramic materials. Therefore, using them as raw materials to prepare high-value-added inorganic fibers can not only effectively utilize solid waste and achieve resource recycling by "turning waste into treasure," but also realize the circular utilization of resources. However, current technologies for directly preparing high-performance inorganic fibers from complex solid waste through high-temperature melting still face a series of severe challenges stemming from the inherent properties of the waste itself. These deep-seated shortcomings significantly limit the performance ceiling and application areas of the products.

[0003] Existing technologies face challenges of high energy consumption and low process tolerance. The high content of refractory components such as silica and alumina in solid waste raw materials forms a highly polymerized silicon-oxygen tetrahedral network, resulting in a generally high melting point. This directly translates into enormous energy consumption and high production costs. Simultaneously, this highly polymerized network structure also leads to extremely high melt viscosity. To achieve continuous wire drawing, operation must be performed within an extremely narrow temperature range with suitable viscosity. Even minor temperature fluctuations can cause drastic viscosity changes, leading to wire breakage, dripping, or the formation of spherical defects, making the entire production process extremely sensitive, resulting in low process stability and yield.

[0004] Secondly, uncontrollable crystallization behavior also restricts the mechanical properties of fibers. Industrial solid waste naturally contains large amounts of oxides such as iron, chromium, and titanium, as well as high concentrations of calcium and magnesium ions. These components are highly efficient nucleating agents and network modifiers in high-temperature melts, lowering the activation energy required for crystallization. Therefore, during the cooling process after being pulled from the high-temperature spinneret, the melt is prone to spontaneous and explosive crystallization, forming unevenly sized, coarse grains, or even dendritic crystals with sharp edges. These coarse crystalline phases become stress concentration points and crack initiation points at the microscopic level, leading to the deterioration of the macroscopic mechanical properties of the fiber, resulting in extremely high brittleness and rendering it worthless as a reinforcing material. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide an inorganic fiber prepared from industrial solid waste and its preparation method. This application achieves multi-level synergistic effects through three additives: rare-earth-doped cryogenic eutectic reduces the viscosity of the solid waste melt and inhibits phase separation by disrupting the silicon-oxygen network and stabilizing the depolymerization structure, creating a uniform melt environment for subsequent processes; carbon-coated composite nanoparticles synergistically reduce viscosity through in-situ carbothermal reduction while clarifying the melt and removing internal defects using reactive gases; after the uniform, low-defect melt is drawn into fibers, the apatite-modified core-shell nanocrystals serve as the core for constructing the microstructure, achieving hierarchical and sequential heterogeneous nucleation under a two-step heat treatment process, inducing the formation of fine and uniform microcrystalline phases within the fiber, thus constructing a high-strength structural foundation; homogenization of the cryogenic eutectic is a prerequisite for the uniform dispersion of subsequent nano-additives; the core-shell nanocrystals, based on this, construct a microcrystalline matrix that imparts high strength to the fiber; and the residual core of the carbon-coated particles is located at the phase interface formed by the former, imparting high toughness to the fiber through a physical mechanism. The three work synergistically to improve the overall mechanical properties.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing inorganic fibers using industrial solid waste, the method comprising:

[0008] S1: Boric acid, calcium fluoride and lanthanum nitrate are mixed and subjected to high-energy wet ball milling with anhydrous ethanol as the ball milling medium to obtain a slurry; the slurry is rotary evaporated to obtain a dry powder, the dry powder is melted, quenched and ground to obtain a rare earth-doped low-temperature eutectic;

[0009] S2: Zirconium oxychloride octahydrate was added to a mixed solvent and stirred to obtain a core sol. An ethanol solution of tetrabutyl titanate was added to obtain reaction solution A. The reaction was stirred at room temperature, centrifuged, washed, and dried to obtain core-shell powder. The core-shell powder was dispersed in deionized water, and calcium hydroxide suspension and phosphoric acid solution were added dropwise to obtain reaction solution B. After the reaction, the solution was aged, centrifuged, washed, dried, and calcined to obtain apatite-modified core-shell nanocrystals.

[0010] S3: Mix silicon nitride and silicon carbide nanoparticles, place them in a tube furnace and heat them under argon protection. Then, introduce an acetylene / argon mixture to carry out a chemical vapor deposition reaction. After cooling, carbon-coated composite nanoparticles are obtained.

[0011] S4: Mix converter steel slag powder and basalt tailings powder, ball mill to obtain a mixture, and pre-calcine it to obtain a basic mixture; place the basic mixture, rare earth doped low-temperature eutectic, surface-modified core-shell nanocrystals and carbon-coated composite nanoparticles in a mixer and mix evenly to obtain a premix; melt and homogenize it in a crucible, cool it, and draw it through a stencil to obtain amorphous glass precursor; heat-treat the amorphous glass precursor by heating it to a first temperature and holding it at that temperature, then continuing to heat it to a second temperature and holding it at that temperature, and cooling it with the furnace to obtain inorganic fibers prepared from industrial solid waste.

[0012] As a preferred technical solution of the present invention, in step S1, the molar ratio of boric acid, calcium fluoride and lanthanum nitrate is (5-10):(1-2):1, for example, it can be (5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5 or 10.0):(1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0):1, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0013] In some optional embodiments, the high-energy wet ball milling time is 4-6 hours, for example, it can be 4.0 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5.0 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours or 6.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0014] In some alternative embodiments, the rotational speed of the ball mill is 300-400 rpm, for example, 300 rpm, 310 rpm, 320 rpm, 330 rpm, 340 rpm, 350 rpm, 360 rpm, 370 rpm, 380 rpm, 390 rpm or 400 rpm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0015] In some optional embodiments, the temperature of the rotary evaporation of the slurry is 50-60°C, for example, 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C or 60°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0016] In some optional embodiments, the melting temperature of the dry powder is 600-700°C, for example, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C or 700°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0017] In some optional embodiments, the melting time of the dry powder is 1-2 hours, for example, it can be 1.0 hours, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0018] As a preferred technical solution of the present invention, in step S2, the volume ratio of ethanol, deionized water and ammonia in the mixed solvent is (20-30):(2-4):1, for example, it can be (20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30):(2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8 or 4.0):1, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0019] In some optional embodiments, the mass fraction of the ammonia water is 25-28 wt%, for example, it can be 25.0 wt%, 25.3 wt%, 25.6 wt%, 25.9 wt%, 26.2 wt%, 26.5 wt%, 26.8 wt%, 27.1 wt%, 27.4 wt%, 27.7 wt%, or 28.0 wt%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0020] In some optional embodiments, the mass fraction of the tetrabutyl titanate ethanol solution is 5-10 wt.%, for example, it can be 5.0 wt.%, 5.5 wt.%, 6.0 wt.%, 6.5 wt.%, 7.0 wt.%, 7.5 wt.%, 8.0 wt.%, 8.5 wt.%, 9.0 wt.%, 9.5 wt.% or 10.0 wt.%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0021] In some optional embodiments, the molar ratio of zirconium oxychloride octahydrate to tetrabutyl titanate is 1:(2-5), for example, it can be 1:2.0, 1:2.3, 1:2.6, 1:2.9, 1:3.2, 1:3.5, 1:3.8, 1:4.1, 1:4.4, 1:4.7 or 1:5.0, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0022] In some optional embodiments, the reaction solution A is stirred at room temperature for 12-24 hours, for example, 12.0 hours, 13.2 hours, 14.4 hours, 15.6 hours, 16.8 hours, 18.0 hours, 19.2 hours, 20.4 hours, 21.6 hours, 22.8 hours, or 24.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0023] In some optional embodiments, the mass fraction of the calcium hydroxide suspension is 0.2-0.5 wt.%, for example, it may be 0.20 wt.%, 0.23 wt.%, 0.26 wt.%, 0.29 wt.%, 0.32 wt.%, 0.35 wt.%, 0.38 wt.%, 0.41 wt.%, 0.44 wt.%, 0.47 wt.%, or 0.50 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0024] In some optional embodiments, the concentration of the phosphoric acid solution is 0.03-0.08 mol / L, for example, it can be 0.030 mol / L, 0.035 mol / L, 0.040 mol / L, 0.045 mol / L, 0.050 mol / L, 0.055 mol / L, 0.060 mol / L, 0.065 mol / L, 0.070 mol / L, 0.075 mol / L or 0.080 mol / L, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0025] The molar ratio of calcium hydroxide to phosphoric acid is 5:3;

[0026] The total mass of calcium hydroxide and phosphoric acid fed is 10-30% of the mass of the core-shell powder, for example, it can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] In some optional embodiments, the reaction time of the reaction solution B is 2-4 hours, for example, it can be 2.0 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3.0 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0028] In some optional embodiments, the aging time of the reaction solution B after reaction is 10-12 hours, for example, it can be 10.0 hours, 10.2 hours, 10.4 hours, 10.6 hours, 10.8 hours, 11.0 hours, 11.2 hours, 11.4 hours, 11.6 hours, 11.8 hours or 12.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0029] As a preferred technical solution of the present invention, in step S3, the mass ratio of silicon nitride to silicon carbide nanopowder is (1-3):1, for example, it can be 1.0:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2.0:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1 or 3.0:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] In some optional embodiments, the temperature of the chemical vapor deposition reaction is 850-950°C, for example, 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C or 950°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0031] In some optional embodiments, the volumetric flow rate ratio of argon to acetylene in the acetylene / argon mixture is (20-40):1, for example, it can be 20:1, 22:1, 24:1, 26:1, 28:1, 30:1, 32:1, 34:1, 36:1, 38:1 or 40:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0032] In some optional embodiments, the chemical vapor deposition reaction time is 30-90 min, for example, 30 min, 36 min, 42 min, 48 min, 54 min, 60 min, 66 min, 72 min, 78 min, 84 min or 90 min, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0033] As a preferred technical solution of the present invention, in step S4, the mass ratio of converter steel slag powder to basalt tailings powder is (1-2):(3-4), for example, it can be 1.0:4.0, 1.1:3.9, 1.2:3.8, 1.3:3.7, 1.4:3.6, 1.5:3.5, 1.6:3.4, 1.7:3.3, 1.8:3.2, 1.9:3.1 or 2.0:3.0, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] In some alternative embodiments, the rotational speed of the ball mill is 300-400 rpm, for example, 300 rpm, 310 rpm, 320 rpm, 330 rpm, 340 rpm, 350 rpm, 360 rpm, 370 rpm, 380 rpm, 390 rpm or 400 rpm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0035] In some alternative embodiments, the ball milling time is 4-8 hours, for example, 4.0 hours, 4.4 hours, 4.8 hours, 5.2 hours, 5.6 hours, 6.0 hours, 6.4 hours, 6.8 hours, 7.2 hours, 7.6 hours, or 8.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0036] In some optional embodiments, the precalcination temperature of the mixture is 950-1050°C, for example, 950°C, 960°C, 970°C, 980°C, 990°C, 1000°C, 1010°C, 1020°C, 1030°C, 1040°C or 1050°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0037] In some optional embodiments, the precalcination time of the mixture is 2-4 hours, for example, it can be 2.0 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3.0 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0038] In some optional embodiments, the mass ratio of the base mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles is 100:(4-12):(0.5-3.0):(0.2-1.5), for example, it can be 100:(4.0, 4.8, 5.6, 6.4, 7.2, 8.0, 8.8, 9.6, 10.4, 11.2, or 12.0):( 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 2.75 or 3.00: (0.20, 0.33, 0.46, 0.59, 0.72, 0.85, 0.98, 1.11, 1.24, 1.37 or 1.50), but not limited to the listed values; other unlisted values ​​within this range also apply.

[0039] In some optional embodiments, the melting and homogenization temperature of the premix is ​​1450-1550°C, for example, it can be 1450°C, 1460°C, 1470°C, 1480°C, 1490°C, 1500°C, 1510°C, 1520°C, 1530°C, 1540°C or 1550°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0040] In some optional embodiments, the melting and homogenization time of the premix is ​​4-6 hours, for example, 4.0 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5.0 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours, or 6.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0041] In some optional embodiments, the premix is ​​melted and homogenized and then cooled to 1280-1380°C, for example, 1280°C, 1290°C, 1300°C, 1310°C, 1320°C, 1330°C, 1340°C, 1350°C, 1360°C, 1370°C or 1380°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0042] In some optional embodiments, the drawing and winding speed is 500-2000 m / min, for example, it can be 500 m / min, 650 m / min, 800 m / min, 950 m / min, 1100 m / min, 1250 m / min, 1400 m / min, 1550 m / min, 1700 m / min, 1850 m / min or 2000 m / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0043] In some optional embodiments, the heating rate during heat treatment of the amorphous glass precursor is 5-10℃ / min, for example, it can be 5.0℃ / min, 5.5℃ / min, 6.0℃ / min, 6.5℃ / min, 7.0℃ / min, 7.5℃ / min, 8.0℃ / min, 8.5℃ / min, 9.0℃ / min, 9.5℃ / min or 10.0℃ / min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0044] In some alternative embodiments, the first temperature is 750-800°C, for example, it can be 750°C, 755°C, 760°C, 765°C, 770°C, 775°C, 780°C, 785°C, 790°C, 795°C or 800°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0045] In some optional embodiments, the heat preservation time at the first temperature is 1-3 hours, for example, it can be 1.0 hours, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2.0 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0046] In some alternative embodiments, the second temperature is 930-980°C, for example, it can be 930°C, 935°C, 940°C, 945°C, 950°C, 955°C, 960°C, 965°C, 970°C, 975°C or 980°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0047] In some optional embodiments, the heat preservation time at the second temperature is 1-3 hours, for example, it can be 1.0 hours, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2.0 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0048] Secondly, the present invention provides an inorganic fiber prepared using industrial solid waste.

[0049] This application introduces rare-earth-doped cryogenic eutectic to lower the system's process temperature and improve melt homogeneity. Boron oxide and calcium fluoride can disrupt and break down the original silicon-oxygen tetrahedral network structure in the solid waste melt, thereby reducing melt viscosity and widening the temperature window for fiber drawing. Simultaneously, the doped rare-earth ions can stabilize the depolymerized network structure, inhibit melt phase separation, and ensure that all subsequent chemical and physical processes are based on a uniform melt environment, providing the necessary prerequisite for the uniform dispersion of other additives.

[0050] Building upon this foundation, this application introduces carbon-coated composite nanoparticles for in-situ regulation of the micro-regional chemical atmosphere within the melt. During high-temperature melting, the pyrolytic carbon layer on the particle surface undergoes an in-situ carbothermic reduction reaction with high-valent iron oxides derived from solid waste raw materials and atmospheric oxidation during the melting process, converting trivalent iron ions, which form the network, into divalent iron ions, which are network modifiers. This chemical transformation not only synergistically reduces the melt viscosity in conjunction with the rare-earth-doped low-temperature eutectic, but also promotes the clarification and homogenization of the melt by generating trace amounts of gas, creating conditions for the preparation of low-defect precursor fibers.

[0051] When a uniform, low-viscosity melt enters the fiber forming and subsequent heat treatment stages, the core-shell nanocrystals modified on the apatite surface can induce the formation of a diffusely distributed nanoscale crystalline phase. Its multi-level core-shell structure—a highly stable zirconia core, a highly efficient nucleating titanium dioxide shell, and an apatite outer layer—enables hierarchical, time-sequential heterogeneous nucleation within a specific temperature range during heat treatment. Through a two-step heat treatment process—namely, sufficient nucleation at a lower temperature followed by controlled crystal growth at a higher temperature—a large number of fine and uniformly distributed microcrystals are formed within the fiber, forming the basis of the composite structure.

[0052] There is a synergistic effect among these three additives. The uniform, low-viscosity melt environment created by the rare-earth-doped low-temperature eutectic is the fundamental prerequisite for achieving uniform dispersion of the other two nano-additives. Based on this, the uniformly distributed apatite-modified core-shell nanocrystals induce uniform fine microcrystals throughout the fiber volume, thereby endowing the fiber with high strength. Simultaneously, thanks to the initial uniform dispersion, after the carbon-coated composite nanoparticles complete their chemical reduction, their residual high-hardness silicon nitride / silicon carbide cores can be distributed at the interface between the crystalline and glassy phases formed by the apatite-modified core-shell nanocrystals, effectively exerting physical toughening through pinning and crack deflection. This synergistic effect enables the inorganic fiber prepared using low-cost industrial solid waste to achieve excellent comprehensive mechanical properties of high strength and high toughness.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] The rare earth-doped low-temperature eutectic introduced in this application utilizes boron oxide and calcium fluoride in its composition to disrupt the silicon-oxygen network, thereby reducing the melt viscosity. At the same time, rare earth ions are used to stabilize the depolymerization network to suppress phase separation, thus achieving the dual purpose of reducing the process temperature and improving melt uniformity.

[0055] The carbon-coated composite nanoparticles introduced in this application utilize the in-situ chemical reduction of high-valent iron ions by their surface carbon in a high-temperature melt, transforming the increased viscosity of the network-forming trivalent iron ions into the decreased viscosity of the network-modified divalent iron ions. This process not only synergistically reduces the melt viscosity, but the resulting gaseous byproducts also clarify and homogenize the melt, collectively creating conditions for the preparation of low-defect fibers.

[0056] The apatite-modified core-shell nanocrystals in this application utilize their multi-level structure composed of zirconium oxide, titanium dioxide, and apatite to achieve hierarchical and time-sequential heterogeneous nucleation through a two-step heat treatment process. Ultimately, a large number of fine and uniformly distributed microcrystals are formed inside the fiber, laying the foundation for constructing a composite structure.

[0057] There is a synergistic effect among the three additives: the rare earth-doped low-temperature eutectic creates a uniform melt base environment; the core-shell nanocrystals modified on the apatite surface construct a fine microcrystalline structure with high strength; and the core of the carbon-coated composite nanoparticles plays a role at these microcrystalline interfaces to improve toughness, ultimately achieving a comprehensive improvement in both strength and toughness. Detailed Implementation

[0058] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The embodiments described herein are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limiting the implementation of the present invention or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application. These technical solutions include technical solutions that employ any obvious substitutions and modifications made to the embodiments described herein.

[0059] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone further purification or processing.

[0060] Example 1

[0061] This embodiment provides an inorganic fiber prepared from industrial solid waste and its preparation method. The preparation method of the inorganic fiber prepared from industrial solid waste specifically includes the following steps:

[0062] S1: Boric acid, calcium fluoride and lanthanum nitrate were mixed in a molar ratio of 8:1.8:1 and subjected to high-energy wet ball milling for 5.5 h with anhydrous ethanol as the ball milling medium to obtain a slurry. The slurry was then rotary evaporated at 58 °C to obtain a dry powder. The dry powder was then melted at 680 °C for 1.8 h, quenched and ground to obtain a rare earth-doped low-temperature eutectic.

[0063] S2: Zirconia oxychloride octahydrate was added to a mixed solvent and stirred to obtain a core sol. The volume ratio of ethanol, deionized water, and 27 wt% ammonia in the mixed solvent was 28:3.5:1. An ethanol solution of 8 wt.% tetrabutyl titanate was added to obtain reaction solution A, in which the molar ratio of zirconium oxychloride octahydrate to tetrabutyl titanate was 1:4. The mixture was stirred at room temperature for 20 h, centrifuged, washed, and dried to obtain core-shell powder. The core-shell powder was dispersed in deionized water, and a calcium hydroxide suspension of 0.4 wt.% and a phosphoric acid solution of 0.06 mol / L were added dropwise to obtain reaction solution B, in which the molar ratio of calcium hydroxide to phosphoric acid was 5:3, and the total mass of both was 25% of the mass of the core-shell powder. After reacting for 3.5 h, the mixture was aged for 11.5 h, centrifuged, washed, dried, and calcined to obtain apatite-modified core-shell nanocrystals.

[0064] S3: Silicon nitride and silicon carbide nanoparticles were mixed at a mass ratio of 2.5:1 and placed in a tube furnace. The mixture was heated to 920°C under argon protection. An acetylene / argon mixture was introduced to carry out a chemical vapor deposition reaction for 75 minutes. After cooling, carbon-coated composite nanoparticles were obtained. The volume flow ratio of argon to acetylene in the acetylene / argon mixture was 35:1.

[0065] S4: Converter slag powder and basalt tailings powder are mixed at a mass ratio of 1:3 and ball-milled at 370 rpm for 7 hours to obtain a mixture. This mixture is then pre-calcined at 1020℃ for 3.5 hours to obtain a basic mixture. The basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles are then mixed uniformly in a mixer to obtain a premix. The mass ratio of the basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles is... The ratio of the materials is 100:10:2.0:1.0. The materials are melted and homogenized in a crucible at 1520℃ for 5.5h, then cooled to 1350℃ and drawn through a stencil at a winding speed of 1500m / min to obtain amorphous glass filaments. The amorphous glass filaments are then heat-treated by heating to a first temperature of 780℃ at 8℃ / min and holding for 2.5h, followed by further heating to a second temperature of 960℃ and holding for 1.5h. The materials are then cooled in the furnace to obtain inorganic fibers prepared from industrial solid waste.

[0066] Example 2

[0067] This embodiment provides an inorganic fiber prepared from industrial solid waste and its preparation method. The preparation method of the inorganic fiber prepared from industrial solid waste specifically includes the following steps:

[0068] S1: Boric acid, calcium fluoride and lanthanum nitrate were mixed in a molar ratio of 5:1:1 and ball-milled for 4 hours with anhydrous ethanol as the ball milling medium to obtain a slurry. The rotation speed was 300 rpm. The slurry was rotary evaporated at 50°C to obtain a dry powder. The dry powder was melted at 600°C for 1 hour, quenched and ground to obtain a rare earth-doped low-temperature eutectic.

[0069] S2: Zirconia oxychloride octahydrate was added to a mixed solvent and stirred to obtain a core sol. The volume ratio of ethanol, deionized water, and 25 wt% ammonia in the mixed solvent was 20:2:1. A reaction solution A was obtained by adding 5 wt.% tetrabutyl titanate in ethanol. The molar ratio of zirconium oxychloride octahydrate to tetrabutyl titanate was 1:2. The reaction was stirred at room temperature for 12 h. After centrifugation, washing, and drying, core-shell powder was obtained. The core-shell powder was dispersed in deionized water, and a calcium hydroxide suspension with a mass fraction of 0.2 wt.% and a phosphoric acid solution with a concentration of 0.03 mol / L were added dropwise to obtain reaction solution B. The molar ratio of calcium hydroxide to phosphoric acid was 5:3, and the total mass of both was 10% of the mass of the core-shell powder. After reacting for 2 h, the mixture was aged for 10 h. After centrifugation, washing, drying, and calcination, apatite-modified core-shell nanocrystals were obtained.

[0070] S3: Silicon nitride and silicon carbide nanoparticles are mixed at a mass ratio of 1:1 and placed in a tube furnace. The mixture is heated to 850°C under argon protection. An acetylene / argon mixture is introduced to carry out a chemical vapor deposition reaction for 30 minutes. After cooling, carbon-coated composite nanoparticles are obtained. The volume flow ratio of argon to acetylene in the acetylene / argon mixture is 20:1.

[0071] S4: Converter slag powder and basalt tailings powder are mixed at a mass ratio of 2:3 and ball-milled at 300 rpm for 4 hours to obtain a mixture. This mixture is then pre-calcined at 950℃ for 2 hours to obtain a basic mixture. The basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles are mixed evenly in a mixer to obtain a premix. The mass ratio of the basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles is 100:4:0.5:0.2. This mixture is then melted and homogenized in a crucible at 1450℃ for 4 hours, cooled to 1280℃, and passed through a perforator at 500℃. Amorphous glass precursors are obtained by drawing the glass precursors at a winding speed of m / min; the amorphous glass precursors are then heat-treated by heating them to a first temperature of 750℃ at a speed of 5℃ / min and holding them at that temperature for 1 hour, followed by further heating to a second temperature of 930℃ and holding them at that temperature for 3 hours, and then cooling them in the furnace to obtain inorganic fibers prepared from industrial solid waste.

[0072] Example 3

[0073] This embodiment provides an inorganic fiber prepared from industrial solid waste and its preparation method. The preparation method of the inorganic fiber prepared from industrial solid waste specifically includes the following steps:

[0074] S1: Boric acid, calcium fluoride and lanthanum nitrate were mixed in a molar ratio of 10:1.2:1 and subjected to high-energy wet ball milling for 4.5 h with anhydrous ethanol as the ball milling medium to obtain a slurry. The slurry was then rotary evaporated at 52 °C to obtain a dry powder. The dry powder was then melted at 620 °C for 1.2 h, quenched and ground to obtain a rare earth-doped low-temperature eutectic.

[0075] S2: Zirconia oxychloride octahydrate was added to a mixed solvent and stirred to obtain a core sol. The volume ratio of ethanol, deionized water, and 26 wt% ammonia in the mixed solvent was 22:2.5:1. An ethanol solution of 6 wt% tetrabutyl titanate was added to obtain reaction solution A, in which the molar ratio of zirconium oxychloride octahydrate to tetrabutyl titanate was 1:3. The mixture was stirred at room temperature for 15 h, centrifuged, washed, and dried to obtain core-shell powder. The core-shell powder was dispersed in deionized water, and a calcium hydroxide suspension of 0.3 wt% and a phosphoric acid solution of 0.04 mol / L were added dropwise to obtain reaction solution B, in which the molar ratio of calcium hydroxide to phosphoric acid was 5:3, and the total mass of both was 15% of the mass of the core-shell powder. After reacting for 2.5 h, the mixture was aged for 10.5 h, centrifuged, washed, dried, and calcined to obtain apatite-modified core-shell nanocrystals.

[0076] S3: Silicon nitride and silicon carbide nanoparticles are mixed at a mass ratio of 1.5:1 and placed in a tube furnace. The mixture is heated to 880°C under argon protection. An acetylene / argon mixture is introduced to carry out a chemical vapor deposition reaction for 45 minutes. After cooling, carbon-coated composite nanoparticles are obtained. The volume flow ratio of argon to acetylene in the acetylene / argon mixture is 25:1.

[0077] S4: Converter slag powder and basalt tailings powder are mixed at a mass ratio of 1:2 and ball-milled at 330 rpm for 5 hours to obtain a mixture. This mixture is then pre-calcined at 980℃ for 2.5 hours to obtain a basic mixture. The basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles are mixed evenly in a mixer to obtain a premix, wherein the mass ratio of the basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles is 100:6:1.0:0.5. This mixture is then melted and homogenized in a crucible at 1480℃ for 4.5 hours, cooled to 1300℃, and passed through a perforator at 800℃. Amorphous glass precursor fibers were obtained by drawing the fibers at a winding speed of m / min; the amorphous glass precursor fibers were then heat-treated by heating them to a first temperature of 760℃ at a speed of 6℃ / min and holding them at that temperature for 1.5h, followed by heating them to a second temperature of 940℃ and holding them at that temperature for 2.5h, and then cooling them in the furnace to obtain inorganic fibers prepared from industrial solid waste.

[0078] Example 4

[0079] This embodiment provides an inorganic fiber prepared from industrial solid waste and its preparation method. The preparation method of the inorganic fiber prepared from industrial solid waste specifically includes the following steps:

[0080] S1: Boric acid, calcium fluoride and lanthanum nitrate were mixed in a molar ratio of 6:2:1 and subjected to high-energy wet ball milling for 6 hours with anhydrous ethanol as the ball milling medium to obtain a slurry. The slurry was then rotary evaporated at 60°C to obtain a dry powder. The dry powder was then melted at 700°C for 2 hours, quenched and ground to obtain a rare earth-doped low-temperature eutectic.

[0081] S2: Zirconia oxychloride octahydrate was added to a mixed solvent and stirred to obtain a core sol. The volume ratio of ethanol, deionized water, and 28 wt% ammonia in the mixed solvent was 30:4:1. A reaction solution A was obtained by adding 10 wt.% tetrabutyl titanate in ethanol. The molar ratio of zirconium oxychloride octahydrate to tetrabutyl titanate was 1:5. The reaction was stirred at room temperature for 24 h. After centrifugation, washing, and drying, core-shell powder was obtained. The core-shell powder was dispersed in deionized water, and a calcium hydroxide suspension with a mass fraction of 0.5 wt.% and a phosphoric acid solution with a concentration of 0.08 mol / L were added dropwise to obtain reaction solution B. The molar ratio of calcium hydroxide to phosphoric acid was 5:3, and the total mass of both was 30% of the mass of the core-shell powder. After reacting for 4 h, the mixture was aged for 12 h. After centrifugation, washing, drying, and calcination, apatite-modified core-shell nanocrystals were obtained.

[0082] S3: Silicon nitride and silicon carbide nanopowders are mixed at a mass ratio of 3:1 and placed in a tube furnace. The mixture is heated to 950°C under argon protection. An acetylene / argon mixture is introduced to carry out a chemical vapor deposition reaction for 90 min. After cooling, carbon-coated composite nanoparticles are obtained. The volume flow ratio of argon to acetylene in the acetylene / argon mixture is 40:1.

[0083] S4: Converter slag powder and basalt tailings powder are mixed at a mass ratio of 1:4 and ball-milled at 400 rpm for 8 hours to obtain a mixture. This mixture is then pre-calcined at 1050℃ for 4 hours to obtain a basic mixture. The basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles are then mixed uniformly in a mixer to obtain a premix. The basic mixture, rare earth-doped cryogenic eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles... The mass ratio is 100:12:3.0:1.5; it is melted and homogenized in a crucible at 1550℃ for 6 hours, then cooled to 1380℃, and drawn through a stencil at a winding speed of 2000 m / min to obtain amorphous glass filaments; the amorphous glass filaments are heat-treated by heating to a first temperature of 800℃ at 10℃ / min and holding for 3 hours, then continuing to heat to a second temperature of 980℃ and holding for 1 hour, and then cooling in the furnace to obtain inorganic fibers prepared from industrial solid waste.

[0084] Comparative Example 1

[0085] This comparative example provides an inorganic fiber prepared from industrial solid waste. The difference from Example 1 is that borax is used instead of rare earth-doped low-temperature eutectic. Other operating steps and process parameters are exactly the same as in Example 1.

[0086] Comparative Example 2

[0087] This comparative example provides an inorganic fiber prepared from industrial solid waste. The difference from Example 1 is that titanium dioxide nanopowder is used to replace the core-shell nanocrystals modified with apatite surface. Other operating steps and process parameters are exactly the same as in Example 1.

[0088] Comparative Example 3

[0089] This comparative example provides an inorganic fiber prepared from industrial solid waste. The difference between this example and Example 1 is that no carbon-coated composite nanoparticles are added. All other operating steps and process parameters are exactly the same as in Example 1.

[0090] The performance of the inorganic fibers prepared from industrial solid waste in Examples 1-4 and Comparative Examples 1-3 was tested, and the specific process is as follows:

[0091] The tensile strength and elongation at break of the fiber were tested using a universal testing machine.

[0092] The test results are shown in Table 1.

[0093] Table 1. Performance test results of inorganic fibers prepared from industrial solid waste in Examples 1-4 and Comparative Examples 1-3.

[0094]

[0095] As shown in Table 1, the test results of Example 1 and Comparative Example 1 indicate that borax was used to replace the rare earth-doped low-temperature eutectic. Because borax lacks the high field strength stabilizing ability of rare earth ions on the depolymerized silicon-oxygen network, microscopic phase separation occurred among the components in the high-temperature melt. This non-uniform melt structure led to inconsistent crystallization driving forces during subsequent heat treatment, easily forming microscopic defects at the phase interface, thus resulting in a decrease in tensile strength. The uniform nucleation effect of the core-shell nanocrystals modified on the apatite surface failed due to their uneven distribution, failing to form an effective fine-grained reinforcing network. This caused premature crack initiation in weak areas under stress, thus reducing its elongation at break.

[0096] As shown in Table 1, the test results of Example 1 and Comparative Example 2 indicate that replacing the core-shell nanocrystals modified with apatite surface with titanium dioxide nanopowder resulted in uncontrolled crystallization within a single temperature range of heat treatment, due to the lack of time-controlled nucleation through a hierarchical structure. This led to the formation of a small number of coarse-sized grains. The fine-grained reinforcement effect failed, and the coarse grains, acting as huge defect sources and stress concentration points, made cracks extremely prone to initiation and propagation, resulting in a decrease in tensile strength. This microstructure, containing a large amount of internal stress and coarse-grained defects, made the material brittle, causing it to fracture under extremely small strain, thus reducing its elongation at break.

[0097] As can be seen from the test results of Example 1 and Comparative Example 3 in Table 1, without the addition of carbon-coated composite nanoparticles, due to the presence of efficient nucleating agents and a uniform melt environment in the system, a fine and uniform microcrystalline structure can be formed inside the fiber. This structure mainly determines the strength and stiffness of the material, so its tensile strength does not change much. However, since no high-hardness nanoparticles are introduced at the interface between the crystalline phase and the glass phase, the system lacks an effective physical toughening mechanism, the interface toughening effect fails, and once microcracks initiate in the matrix, they will propagate rapidly without hindrance and cannot effectively dissipate fracture energy through pinning and crack deflection, so its elongation at break decreases.

[0098] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing inorganic fibers using industrial solid waste, characterized in that, The preparation method includes: S1: Boric acid, calcium fluoride and lanthanum nitrate are mixed and subjected to high-energy wet ball milling with anhydrous ethanol as the ball milling medium to obtain a slurry; the slurry is rotary evaporated to obtain a dry powder, the dry powder is melted, quenched and ground to obtain a rare earth-doped low-temperature eutectic; S2: Zirconium oxychloride octahydrate was added to a mixed solvent and stirred to obtain a core sol. An ethanol solution of tetrabutyl titanate was added to obtain reaction solution A. The reaction was stirred at room temperature, centrifuged, washed, and dried to obtain core-shell powder. The core-shell powder was dispersed in deionized water, and calcium hydroxide suspension and phosphoric acid solution were added dropwise to obtain reaction solution B. After the reaction, the solution was aged, centrifuged, washed, dried, and calcined to obtain apatite-modified core-shell nanocrystals. S3: Mix silicon nitride and silicon carbide nanoparticles, place them in a tube furnace and heat them under argon protection. Then, introduce an acetylene / argon mixture to carry out a chemical vapor deposition reaction. After cooling, carbon-coated composite nanoparticles are obtained. S4: Mix converter steel slag powder and basalt tailings powder, ball mill to obtain a mixture, and pre-calcine it to obtain a basic mixture; place the basic mixture, rare earth doped low-temperature eutectic, surface-modified core-shell nanocrystals and carbon-coated composite nanoparticles in a mixer and mix evenly to obtain a premix; melt and homogenize it in a crucible, cool it, and draw it through a stencil to obtain amorphous glass precursor; heat-treat the amorphous glass precursor by heating it to a first temperature and holding it at that temperature, then continuing to heat it to a second temperature and holding it at that temperature, and cooling it with the furnace to obtain inorganic fibers prepared from industrial solid waste.

2. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S1: The molar ratio of boric acid, calcium fluoride, and lanthanum nitrate is (5-10):(1-2):

1.

3. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S2: The volume ratio of ethanol, deionized water and ammonia in the mixed solvent is (20-30):(2-4):1; The ammonia solution has a mass fraction of 25-28 wt%.

4. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S2: The molar ratio of zirconium oxychloride octahydrate to tetrabutyl titanate is 1:(2-5).

5. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S2: The molar ratio of calcium hydroxide to phosphoric acid is 5:3; The total mass of calcium hydroxide and phosphoric acid fed into the feed is 10-30% of the mass of the core-shell powder.

6. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S3: The mass ratio of silicon nitride to silicon carbide nanopowder is (1-3):

1.

7. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S4: The mass ratio of converter steel slag powder to basalt tailings powder is (1-2):(3-4).

8. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S4: The mass ratio of the basic mixture, rare earth-doped low-temperature eutectic, surface-modified core-shell nanocrystals, and carbon-coated composite nanoparticles is 100:(4-12):(0.5-3.0):(0.2-1.5).

9. The method for preparing inorganic fibers from industrial solid waste according to claim 1, characterized in that, In S4: The first temperature is 750-800℃; The second temperature is 930-980℃.

10. An inorganic fiber prepared from industrial solid waste by the preparation method according to any one of claims 1-9.

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