Process for the efficient plasma-based production of amorphous silica, alumina, and titania from oxide precursors

Abstract

A plasma in-flight process and apparatus for producing amorphous silica, alumina, and titania from solid crystalline oxide feedstocks is disclosed. The method utilizes a plasma torch to directly melt feedstock materials—such as quartz, bauxite, or titanium minerals— within a plasma plume inside a reactor. Downstream of the torch, a quenching system based on injected air, nitrogen, or argon rapidly cools the molten particles to prevent recrystallization and promote the formation of amorphous oxide powders. The reactor system includes a gas outlet and collection system to recover both micro- and nano-sized particles. The process eliminates the need for chemical precursors, solvents, or carbon reductants and offers a single-step, emission-free, and energy-efficient method for producing high-performance amorphous materials at industrial scale.

Description

PROCESS FOR THE EFFICIENT PLASMA-BASED PRODUCTION OF AMORPHOUSSILICA, ALUMINA, AND TITANIA FROM OXIDE PRECURSORSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This Application claims priority on U.S. Provisional Application No. 63 / 641 ,354, now pending, filed on May 1 , 2024, which is herein incorporated by reference.FIELD

[0002] The present subject matter relates to advanced materials and, more particularly, to the production of amorphous oxide powders, including amorphous silica, amorphous alumina, and amorphous titania, using an in-flight plasma process. These materials are intended for use in a range of high-performance applications, such as cement and concrete additives, catalysts, battery materials, electronic coatings, and environmental remediation.BACKGROUND

[0003] Cement is essential in the construction industry, serving as a foundational material celebrated for its versatility and strength. It functions as the primary binder in concrete, mixed with aggregates like sand and gravel, ensuring the structural integrity of diverse infrastructures such as buildings, bridges, and highways.

[0004] This adaptability allows cement to be utilized across various construction elements, from foundations to intricate architectural designs, ensuring creative flexibility and structural soundness. The durability of cement-based structures is critical, providing longevity against environmental challenges such as weathering and corrosion, thus playing a vital role in building reliable infrastructure.

[0005] Despite its widespread use and significant economic impact through job creation and industry stimulation, cement production faces sustainability challenges, mainly due to its substantial carbon emissions. In response, the industry has been innovating greener practices and developing eco-friendly alternatives.

[0006] This approach opens new possibilities for the concrete cement industry. By utilizing additives like plasticizers for improved workability, pozzolanic materials for enhanced strength, and air-entraining agents for frost resistance, we can significantly elevate concrete's performance.

[0007] In the cement and concrete industry, additives such as silica fume, fly ash, and ground granulated blast furnace slag (GGBFS) significantly enhance the concrete's properties, while reducing its carbon footprint.

[0008] Silica fume, also known as amorphous silica (U.S. Patents No. 11447419B2 and No. US10457603B2), is a byproduct of silicon metal or ferrosilicon alloy production and contains ultra-fine particles that increase concrete’s compressive and tensile strength, reduce permeability, and enhance durability. It is especially beneficial for high- performance and high-strength concrete applications.

[0009] Fly ash (U.S. Patent No. US7288148B2 and U.S. Patent Application Publication No. US20220234952A1 ) is produced from coal combustion, improves workability, reduces hydration heat, and enhances durability, making it suitable for mass concrete structures like large foundations and dams.

[0010] GGBFS (U.S. Patent No. US10233116B1 ) is a byproduct of iron and steel making, enhances workability and durability, and is particularly valuable in marine environments where sulfate resistance is crucial.

[0011] Silica fume is an interesting alternative to fly ash and GGBFS in improving workability and durability of concrete. Silica fume offers exceptional performance in enhancing concrete's mechanical properties and durability under severe environmental conditions. Its ability to significantly reduce concrete's permeability makes it ideal for high- strength, durable applications, positioning silica fume as the most promising additive for optimizing current cement and concrete formulations, especially in demanding durability and strength contexts.

[0012] Silica fume or amorphous silica is conventionally produced as a by-product of the complex carbothermic production of silicon or ferrosilicon. Quartz is mined and extracted, followed by crushing and sieving to reach the desired process particle size range. Then it is chemically reduced to silicon or ferrosilicon in an arc furnace in the presence of a carbon source, and iron in the case of ferrosilicon, consuming largeamounts of energy, therefore resulting in a significant quantity of CO2 emission, while generating solid byproducts such as silica fume and slag. Silica fume produced from the carbotherm ic reduction as a by-product represents a production ratio of 1 / 3, meaning that for each ton of silicon or ferrosilicon produced, there are 333kg of fumed silica by-products. The process is multistep and highly polluting, emitting massive amounts of greenhouse gases (GHGs).

[0013] Considering the complete product lifecycle, the conventional process of making amorphous silica has a high carbon footprint of 15-30 kg CO2 eq per kg of product, as the carbotherm ic production of silicon has a carbon footprint of 5-10 kg CO2 eq per kg of product. Moreover, the conversion yield of the process in each step is lower than 100%; for instance, industrially, the maximum conversion yield of the carbothermic production of silicon is only 80%, resulting in the remaining 20% being low-quality and low-purity silica fume by-product.

[0014] Given the several drawbacks of the current carbothermic production process for amorphous silica, namely high energy consumption and CO2 emission, there is a need for a new apparatus and method capable of producing amorphous silica in a single, direct step with the elimination of CO2 emissions and significantly enhancing energy efficiency; responding to the critical environmental and sustainability challenges facing the cement industry today.

[0015] Alumina (AI2O3), also known as aluminum oxide, is one of the most widely used advanced ceramic materials due to its excellent thermal, chemical, and mechanical stability. It finds application across a wide range of industries including catalysis, energy storage, coatings, microelectronics, and environmental remediation. Among its various forms, amorphous alumina has gained increasing interest due to its high surface area, non-crystalline structure, and improved dispersion properties, especially in catalytic and surface-engineered applications.

[0016] In the chemical and petrochemical industries, amorphous alumina serves as a support material for catalysts, particularly in hydrocracking, desulfurization, and fluid catalytic cracking (FCC) processes. Its disordered structure allows for higher interaction with active catalytic sites and better anchoring of nanoparticles. In batteries, amorphous alumina coatings enhance the stability and cycle life of cathodes and anodes in lithium-ion cells. In electronics, it is used as a high-k dielectric layer and as a protective or insulating coating on sensitive devices due to its chemical resistance and dielectric strength.

[0017] Commercial production of amorphous alumina has traditionally relied on chemical routes, such as sol-gel processing, co-precipitation from aluminum salts (e.g., AI(NO3)3or AI2(SO4)3), or the hydrolysis of aluminum alkoxides. These processes are followed by drying and calcination to remove residual solvents and induce the desired phase. For example, Chinese Patent No. 104,944,455 A describe sol-gel methods for alumina synthesis, while U.S. Patent No. 3,886,264 A discusses aluminum alkoxide decomposition under controlled atmospheres.

[0018] While effective at lab scale, these chemical processes pose scalability challenges for industrial deployment. They often require hazardous solvents, extended reaction times, complex washing steps, and careful pH control, making them time-consuming and costly. In addition, they produce chemical waste streams that require neutralization and handling, increasing the environmental burden.

[0019] Furthermore, these methods generally use high-purity chemical precursors derived from bauxite through the Bayer process, which itself is energy-intensive and produces large volumes of red mud waste. The reliance on multi-step processing and energy-intensive calcination to remove organics adds to the overall carbon footprint of the production.

[0020] Amorphous alumina derived from sol-gel or precipitation routes often exhibits low thermal stability, requiring further stabilization treatments. Yet high-temperature posttreatment risks transforming the material into y- or a-alumina, thus losing its amorphous character and surface area — defeating the purpose in applications where disordered structure is essential.

[0021] The variability in particle morphology, porosity, and surface functionalization across different synthesis routes results in inconsistent performance in catalytic, dielectric, and electrochemical applications. Moreover, when organic binders or templates are used, residual carbon or sulfur species may remain in the final powder unless rigorously removed.

[0022] Recent studies and patents, such as U.S. Patent No. 9,196,901 B2 and U.S. Patent Application No. 9,692,039 B2, describe the benefits of nanostructured and amorphous alumina in battery separators and ceramic composites. Yet, most of these techniques remain dependent on complex chemical syntheses or template-based methods.

[0023] Titanium dioxide (TiO2) is a multifunctional metal oxide widely used in applications ranging from pigments and UV-protective coatings to photocatalysts, gas sensors, and energy storage materials. In its traditional crystalline forms (anatase, rutile, and brookite), TiO2is known for its high refractive index, chemical stability, and strong oxidative photocatalytic activity. However, amorphous titania has recently garnered interest for its enhanced surface activity, improved ionic mobility, and broader functionality in emerging technologies.

[0024] Amorphous TiO2exhibits a disordered atomic structure that imparts unique properties such as higher density of surface defects, tunable band gap, improved ion diffusion, and increased adsorption capacity. These characteristics are especially beneficial for photocatalysis under low-light conditions, electrochemical energy storage, and functional coatings with self-cleaning or antimicrobial properties.

[0025] Key applications of amorphous titania include its use as a photocatalyst for air and water purification, an anode material in lithium-ion and sodium-ion batteries, a UV absorber in sunscreens and protective coatings, and a gas sensor for detecting volatile organic compounds (VOCs). These technologies increasingly require high-purity, nanostructured, or mesoporous TiO2with well-controlled surface chemistry and amorphous structure.

[0026] Conventional methods for synthesizing amorphous titania include sol-gel processes, hydrothermal synthesis, and precipitation from Ti alkoxides or TiCI4under acidic conditions. These processes are described, for example, in U.S. Patent No. 7,935,329 B2 and U.S. Patent Application No. 8,137,647 B2. The resulting gels or colloids are then dried and sometimes mildly calcined to yield amorphous titania, though high temperatures risk partial crystallization.

[0027] These chemical approaches suffer from several drawbacks: they are timeconsuming, difficult to scale, sensitive to environmental conditions (e.g., moisture and air),and rely on corrosive, flammable, or toxic precursors such as titanium isopropoxide or titanium tetrachloride. Additionally, they require controlled atmospheres, alcohol-based solvents, or surfactants that complicate waste handling and raise safety concerns.

[0028] In many cases, the final product contains residual chlorine, carbon, or sulfur species that must be removed through post-processing, which may trigger undesired crystallization or reduce yield. Furthermore, reproducibility of the particle size distribution, morphology, and amorphous content is often limited by batch-to-batch variability and drying kinetics.

[0029] Crystalline TiO2is also known to transition between anatase and rutile phases depending on temperature and synthesis conditions. Achieving and retaining an amorphous structure at industrial scale is challenging, especially under conventional heat treatments. While methods such as ball milling or laser ablation can induce partial amorphization, they are not scalable and can introduce impurities or surface damage.SUMMARY

[0030] It would thus be desirable to provide a novel apparatus and process for producing amorphous silica, amorphous alumina, and amorphous titania.

[0031] The embodiments described herein provide, in one aspect, a plasma in-flight process for continuously producing amorphous silica, amorphous alumina, and amorphous titania (directly from solid oxide feedstocks in a single-step, high-temperature conversion method) with significantly lower energy requirements and carbon footprint compared to conventional chemical or carbothermic processes.

[0032] Also, the embodiments described herein provide, in another aspect, an apparatus configured to melt and subsequently quench the liquid phase of silica, alumina, or titania particles to solidify them into their amorphous form and prevent recrystallization, all within a single continuous step.

[0033] Furthermore, the embodiments described herein provide, in another aspect, a plasma in-flight process to convert crystalline feedstocks — such as quartz (SiO2), gibbsite or bauxite (AI2O3xH2O), and ilmenite or rutile (TiO2) — directly into their corresponding amorphous phases without the use of chemical additives or reductants.

[0034] Furthermore, the embodiments described herein provide, in another aspect, a plasma in-flight process for producing amorphous silica, alumina, and titania that is substantially waste-free and does not generate hazardous by-products or chemical effluents.

[0035] Furthermore, the embodiments described herein provide, in another aspect, an apparatus to thermally melt and convert crystalline quartz, gibbsite or bauxite, or titania minerals into amorphous silica, alumina, or titania, respectively, without the use of additives and without generating by-products.

[0036] Furthermore, the embodiments described herein provide, in another aspect, a plasma in-flight process for producing amorphous silica, amorphous alumina, and amorphous titania, comprising the steps of:

[0037] crushing and milling oxide feedstock, including quartz rock, bauxite ore, or titanium-bearing minerals, into micron- to millimeter-sized crystalline powders;

[0038] generating, within the in-flight plasma reactor, a high-temperature plasma plume at the tip of the plasma torch;

[0039] feeding the crystalline oxide powders into the plasma plume of the plasma torch inside the in-flight plasma reactor;

[0040] rapidly quenching the molten oxide particles to prevent recrystallization and to resolidify them into an amorphous phase; and

[0041] removing the resulting amorphous silica, alumina, or titania in the form of fine powder particles from the reactor.

[0042] Furthermore, the embodiments described herein provide, in another aspect, an apparatus for producing amorphous silica, alumina, or titania, comprising a reactor adapted to support a plasma torch mounted at the top, wherein a plasma plume generated at the tip of the torch is adapted to melt solid feedstocks such as quartz, bauxite, or titanium-bearing minerals; a quenching system — using air and / or nitrogen and / or argon- containing gases — adapted to rapidly cool the molten oxides and convert them into amorphous particles; and an outlet configured to allow the collection and discharge of the resulting amorphous oxide powders from the reactor.

[0043] Furthermore, the embodiments described herein provide in another aspect that a path of injected crystalline powder through the plasma plume starts at an angle of90 degrees, preferably at an angle of 75 to 90 degrees and more preferably at an angle of 60 degrees to 90 degrees to the plasma plume to avoid crystalline particle reflection by the plasma plume vortex.

[0044] Furthermore, the embodiments described herein provide in another aspect the quenching system including at least one gas injection port, preferably two gas injection ports, and, more preferably, three injection ports located at an angle of 120 degrees apart.

[0045] Furthermore, the embodiments described herein provide, in another aspect, a drop box configured to collect larger amorphous silica, alumina, or titania agglomerates as a stream of hot gas and entrained amorphous particles exits the reactor through the outlet, allowing for separation of coarser material prior to downstream collection or filtration.

[0046] Furthermore, the embodiments described herein provide in another aspect a gas / l iquid cooler downstream of the drop box to cool the stream of hot gas.

[0047] Furthermore, the embodiments described herein provide, in another aspect, a fine particulate filtration system positioned downstream — such as a HEPA or equivalent high-efficiency filter — adapted to further purify the process gas stream and remove any residual traces of amorphous silica, alumina, or titania particles.

[0048] Furthermore, the embodiments described herein provide, in another aspect, an induced draft fan downstream of the fine particulate filter for drawing the gas out of the reactor and providing sub-atmospheric pressure.

[0049] Furthermore, the embodiments described herein provide, in another aspect, a Plasma Torch In-flight Reactor (PTIFR) process for producing amorphous silica, alumina, or titania, including the steps of:

[0050] feeding crystalline oxide powders, such as crushed quartz (crystalline SiO2), bauxite containing gibbsite, boehmite, or diaspore (crystalline AI(OH)3orAIO(OH)), or titanium-bearing minerals such as rutile, anatase, or ilmenite (crystalline TiO2or FeTiO3), into a Plasma Torch In-flight Reactor (PTIFR) through a feeding port on the side of the reactor;

[0051] feeding the crystalline oxide powders — such as quartz, gibbsite, boehmite, diaspore, rutile, anatase, or ilmenite — directly through the plasma torch and into the plasma plume enhances the production efficiency of amorphous silica, alumina, or titania;

[0052] by enhancing the thermal and fluidic interaction between the injected crystalline particles and the high-temperature plasma plume;

[0053] by reducing the percentage of particle reflection and backflow typically encountered during side-wall injection;

[0054] by increasing the plasma torch power to expand the plume diameter and length, thereby improving the melting of the crystalline SiO2, AI2O3, or TiO2particles;

[0055] generating, within the reactor, a high-temperature plasma plume at the tip of the plasma torch capable of melting the injected crystalline feedstocks;

[0056] rapidly quenching the molten oxide materials to avoid recrystallization and resolidify them into a fully amorphous structure in the form of microparticles; and

[0057] removing the resulting amorphous silica, alumina, or titania particles in powder or agglomerated form from the reactor through a dedicated outlet system.BRIEF DESCRIPTION OF THE DRAWINGS

[0058] For a better understanding of the embodiments described herein and to show more clearly how they may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, which show at least one exemplary embodiment of the apparatus and process for producing amorphous silica, alumina, and titania from corresponding crystalline feedstocks, and in which:

[0059] Fig. 1 is an exemplary schematic vertical cross-sectional view of a reactor for producing amorphous silica, alumina, or titania, in accordance with an exemplary embodiment of the plasma in-flight process;

[0060] Fig. 2 is an exemplary schematic diagram of a process for producing amorphous silica, alumina, or titania, in accordance with an exemplary embodiment of the plasma in-flight reactor system;

[0061] Fig. 3 is an exemplary schematic vertical cross-sectional view of a powder feeder port nozzle, illustrating the multi-angle feeding mechanism for introducingcrystalline oxide powders into the plasma plume, in accordance with an exemplary embodiment;

[0062] Figs. 4a and 4b are Scanning Electron Microscopy (SEM) images showing, respectively: (a) the quartz feedstock (crystalline silica) and (b) the produced amorphous silica using the Plasma Torch In-flight Reactor (PTIFR) process. Silica was selected as a representative oxide to experimentally validate the performance and effectiveness of the system, in accordance with an exemplary embodiment;

[0063] Fig. 5 is a graph showing the X-ray Diffraction (XRD) patterns of the quartz feedstock (demonstrating 100% crystallinity) and the amorphous silica produced using the Plasma Torch In-flight Reactor (PTIFR), exhibiting an amorphous content ranging from 64.2% to 99.1 %, in accordance with an exemplary embodiment.DESCRIPTION OF VARIOUS EMBODIMENTSSilica

[0064] It is therefore desirable to convert crystalline silicon dioxide in the solid quartz form directly into amorphous silica in one single step, with lower emissions of pollutants, including GHGs, and at a lower cost. This can be achieved by directly melting the crystalline SiO2 at high temperatures and resolidifying it to amorphous SiO2. Because of the high temperatures required in this process (+2000°C), conventional heating methods, such as combustion flames by burners, are not well adapted. Conventional electrical heating methods, such as resistive heating are temperature limited and risk having the heating element coated in silica powder, leading to reduced efficiency and making this heating method not adapted for this process.

[0065] One way to achieve the high temperature and optimum residence time required for the production of silica is to use a plasma torch in the Plasma Torch In-flight Reactor (PTIFR) disclosed herein. A plasma plume can attain temperatures exceeding the melting temperature of silica, meeting the requirement of the process. The plasma torch is also not subject to fouling or loss in efficiency during the amorphous silica production process. Moreover, the PTIFR process is highly scalable.

[0066] The amorphous silica powder produced by PTIFR is not only well adapted as an additive to the needs of the cement industry, but also promotes environmental sustainability, a crucial aspect in today's construction industry.Alumina

[0067] The Plasma Torch In-Flight Reactor (PTIFR) can be adapted for alumina production by feeding either calcined alumina, bauxite-derived boehmite (y-AIOOH), or aluminum hydroxide (AI(OH)3) into a high-temperature plasma jet. The plasma melts the particles (>2000°C), and subsequent rapid quenching prevents crystallization, producing a fine amorphous alumina powder.

[0068] Given the pressing need for cleaner, scalable, and energy-efficient processes for amorphous alumina production, an alternative approach that bypasses these chemical steps and directly converts solid mineral feedstock to amorphous alumina is highly desirable. The use of a plasma-based in-flight melting and quenching system provides such an opportunity.

[0069] Plasma-based processing offers several advantages: it eliminates the need for solvents, pH control, surfactants, and multiple batch reactors. It minimizes waste streams, requires no organic precursors, and produces non-agglomerated, high-surface-area powders in a continuous and scalable manner.

[0070] In contrast to the energy-intensive Bayer-derived route, this method could directly use impure or intermediate-grade alumina feedstocks, lowering both material cost and environmental impact. Moreover, it avoids red mud generation and downstream chemical treatments, aligning with sustainability targets in advanced materials production.

[0071] The plasma system also enables fine control over residence time and thermal history, allowing tuning of surface area, hydroxyl content, and particle morphology. This opens the door for application-specific customization, such as hydrophilic alumina for catalysis or electrically insulating grades for electronics.

[0072] The plasma-based PTIFR method provides a single-step, solvent-free, and carbon-free route to high-purity amorphous alumina. It addresses the limitations of current methods while enabling the development of next-generation materials for catalysis, energy, and electronics, with reduced energy consumption and zero process emissions.

[0073] The amorphous alumina produced by the PTFIR process is particularly suited for emerging green technologies, such as solid-state batteries, hydrogen fuel cells, and high- temperature insulators. Its production in a sustainable manner supports broader climate and circular economy goals, meeting the demand for high-performance materials with a low environmental footprint.Titania

[0074] To overcome the limitations of the current production process for amorphous titania, a direct thermal route that transforms titania into its amorphous phase without the use of solvents, toxic reagents, or multistep purification is highly desirable. In this regard, the Plasma Torch In-Flight Reactor (PTIFR) offers a promising platform to produce amorphous TiO2from naturally occurring or industrial-grade feedstocks.

[0075] The PTIFR process involves the injection of titania particles — derived from ilmenite, anatase, rutile, or metatitanic acid — into a high-temperature plasma jet. The particles are instantaneously melted at temperatures exceeding 3000°C and then rapidly quenched to prevent crystalline phase formation. The result is a fine, high-purity amorphous titania powder with tailorable surface area and reactivity.

[0076] This process eliminates the need for precursors like TiCI4or titanium alkoxides, reducing both material cost and environmental impact. It produces no liquid waste and requires no drying or post-treatment, offering a clean, continuous, and scalable route to advanced titania materials.

[0077] Compared to sol-gel or hydrothermal methods, the PTIFR process allows for better control of particle size distribution, avoids agglomeration, and produces powders that are immediately ready for application in catalysis, coatings, or electrochemistry. It also avoids the generation of harmful by-products like HCI or organic solvent vapors.

[0078] Amorphous titania produced in this way is especially suited for use in photocatalytic air filters, self-cleaning window coatings, hydrogen evolution catalysts, and battery electrodes, where high surface area and disordered structure enhance performance. The process enables the creation of metastable amorphous titania that retains its high reactivity without compromising safety or sustainability.

[0079] Recent innovations, such as those described in U.S. Patent No. 8,883,674 B2 and U.S. Patent Application No. 12,161 ,996 B2 demonstrate the rising demand for amorphous or mesoporous TiO2in energy and environmental sectors. However, current methods described in these disclosures are limited by precursor cost, waste handling, or scalability constraints.

[0080] The PTIFR method solves these issues of by precursor cost, waste handling, or scalability constraints by using solid oxide powders instead of molecular precursors, transforming titania directly into its amorphous phase without any intermediate chemistry. It offers precise thermal control, minimal contamination, and full compatibility with industrial titania grades derived from mining or pigment production.

[0081] Therefore, the present subject matter discloses a single-step, solvent-free, emission-free plasma process to produce amorphous titania from solid precursors. This method not only provides a sustainable and cost-effective solution to conventional TiO2synthesis challenges, but also enables next-generation applications in environmental remediation, energy storage, and functional coatings — meeting the performance demands of future technologies with reduced ecological impact.

[0082] The aforementioned drawbacks can be overcome by the present subject matter, which utilizes an electric Plasma Torch In-flight Reactor (PTIFR), in which plasma is generated at the tip of a plasma torch system 100 as shown on Fig. 1 to melt crystalline oxide powders — such as silica, alumina, or titania — directly. This configuration enhances the overall energy efficiency of the process, eliminates unnecessary energy losses, and improves the thermal and operational stability of the continuous amorphization process.

[0083] Referring to Fig. 1 , there is shown a schematic representation of the Plasma Torch In-flight Reactor (PTIFR). PTIFR is composed of a plasma torch system 100 installed on the top of an eductor system 200 installed on the top of a reactor system 300.

[0084] The plasma torch system 100, preferably operating with air, nitrogen, and / or argon as the plasma gas, provides the heat energy required to melt crystalline oxide powders — such as quartz, bauxite, or titania minerals — via a high-temperature plasma plume 210. This plume is generated by a DC arc 105 stroked between a cathode101 and a water-cooled anode 104. Preferably, the plasma torch 100 is designed with a hollow electrode configuration, allowing the integration of a secondary powder feeding system 106, which delivers oxide powders directly into the core of the plasma plume 210 for enhanced energy transfer and melting efficiency.

[0085] A stream of crystalline oxide powder, such as crushed quartz, bauxite, or titanium-bearing minerals, preferably in a particle size range of less than 1 mm, is fed continuously or intermittently into the eductor system 200 through a feed port 203 with the assistance of a carrier gas, preferably air, nitrogen (N2), and / or argon (Ar). The eductor system 200 is thermally engineered to maintain an internal temperature above the melting point of the injected crystalline powder, particularly at the upper section — preferably exceeding 2,000°C — to ensure sufficient residence time for full melting of the particles. The lower section of the eductor includes a quenching system, comprising three equally spaced gas injection ports 206, 207, and 208, through which the molten oxide droplets 211 are rapidly cooled to prevent recrystallization and are resolidified into amorphous powder particles 212, such as amorphous silica, alumina, or titania.

[0086] The reactor system 300 is designed to enable effective heat dissipation from the plasma heating source without relying on a water-cooling system. It is constructed from two vertically separated steel shells, featuring an internal hot-face refractory lining 301 and an insulating layer 302. The elimination of water-cooling minimizes heat loss through the reactor walls, thereby enhancing the overall energy efficiency of the process. To ensure complete solidification of any molten oxide particles that bypass the initial quenching zone in the eductor, the upper section of the reactor system 300 includes two additional quenching ports 303 and 304. An off-gas outlet 305 is positioned at the bottom of the reactor system to allow evacuation of hot gas streams along with a portion of the amorphous product — be it silica, alumina, or titania — while the remaining portion is directed to a bottom bucket collector 306 for particle recovery.

[0087] Now, turning to Fig. 2, crystalline oxide powders, such as crushed quartz, bauxite, or titanium-bearing minerals, are introduced into an eductor system ES (e.g., the eductor system 200 of Fig. 1 ) by way of an automated powder feeder 4. The crystalline powder 209 is introduced intermittently or continuously into the eductor system ES. A plasma torch system PTS (e.g., the plasma torch system 100 of Fig. 1 ) generates aplasma plume (reference 210 in Fig. 1 ) inside the eductor system using a DC power supply 2. The plasma plume melts the crystalline oxide powder (reference 209 in Fig. 1 ) into a molten phase (reference 211 in Fig. 1 ). A quenching gas, such as air, nitrogen (N2), or argon (Ar), is injected into the eductor system to initiate rapid cooling.

[0088] As the molten material cools, it solidifies into amorphous oxide powder (reference 212 in Fig. 1 ), such as amorphous silica, alumina, or titania, which exits the eductor system ES and is quenched again upon entering a reactor system RS (e.g., the reactor system 300 of Fig. 1 ). The stream of hot gas and a portion of the micro-sized amorphous oxide particles exit the reactor system through the off-gas outlet (reference 305 in Fig. 1 ) and are partially collected by a drop box 5, while the remaining portion is recovered in a bottom bucket collector 9 located at the base of the reactor system.

[0089] The hot gas stream is then cooled using an indirect gas / liquid cooler (6) and passed through a fine particulate filter (7) to ensure that no amorphous oxide particles are released into the atmosphere. An induced draft fan (8) is used to extract the gas from the Plasma Torch In-flight Reactor system and maintain a slightly negative pressure throughout the apparatus, ensuring controlled flow dynamics and safe operation.

[0090] Referring to Fig. 3, there is shown a schematic representation that details the powder feeder port 203 of Fig. 1 , which is preferably made of a material that can withstand higher temperature and is oxidation resistant as it is closer to the plasma plume.

[0091] An feeding angle mechanism 400 illustrated in Fig. 3 consists of 5 outlet ports curved on the nozzle of the feeder tube allowing to feed powder directly into the plume with a direct angle of 90 degrees for sub-port 1 (reference 401 ), an angle of 60 degrees for the sub-ports 2 (reference 402) and 5 (reference 405) and an angle of 75 degrees for the sub-ports 3 (reference 403) and 4 (reference 404). This feeding mechanism 400 allows to cover a wide portion of the plasma plume, thereby enhancing the surface contact between the powder feedstock and the plasma plume.

[0092] Turning to Fig. 4, it displays a microstructural comparison between (a) the feedstock quartz (representing 100% crystalline silica) and (b) the produced amorphous silica, with an amorphous content of up to 99.1 %, generated using the PTIFR process. In this exemplary embodiment, silica was selected as a representative oxide to experimentally validate the proof of concept for the plasma in-flight conversion system.Quartz was used as the feedstock material due to its well-known crystallinity and high melting point, and the resulting amorphous silica product serves as a direct benchmark of process performance and transformation efficiency.

[0093] As shown in the SEM image (Fig. 4a), the crystalline silica feedstock exhibits a highly ordered atomic arrangement, which manifests in sharp-edged particles with clearly defined facets, cleavage planes, and geometric surfaces. These features are characteristic of a well-developed lattice structure, reflecting long-range order typical of crystalline solids. In contrast, the amorphous silica product shown in SEM image (Fig. 4b) demonstrates a markedly different morphology. The particles appear disordered, with irregular, smoother, and more rounded surfaces, lacking the sharp features observed in the crystalline feed. This morphological transformation is indicative of a successful transition from a crystalline to a non-crystalline (amorphous) phase, confirming the capability of the PTIFR system to achieve complete amorphization under the described conditions.

[0094] Figure 5 displays a crystallinity comparison between the feedstock quartz (100% crystalline) and multiple samples of amorphous silica produced using the PTIFR process, exhibiting amorphous content ranging from 64.2% to 99.1 %. This figure provides further experimental evidence validating the effectiveness of the plasma in-flight conversion method. Quartz, used as the crystalline silica feedstock, serves as a benchmark material due to its well-established structural and diffraction characteristics.

[0095] In X-ray Diffraction (XRD) analysis, crystalline silica produces sharp, well-defined diffraction peaks at specific 29 angles, corresponding to the long-range periodicity and regular lattice spacing of the quartz crystal structure. These peaks are highly characteristic and allow for the precise identification of different polymorphs of crystalline silica.

[0096] By contrast, the XRD patterns of the produced amorphous silica samples show a broad, diffuse hump, typically centered around 26 = 20°-25°, which is characteristic of non-crystalline materials. This broad halo arises from the absence of long-range atomic order and reflects the short-range disorder inherent in amorphous structures. The lack of sharp diffraction peaks in these samples confirms successful disruption of the crystalline lattice and transformation into an amorphous phase.

[0097] The data shown in Figure 5 further illustrate that the PTIFR process enables controlled adjustment of amorphous content in the final product. A gradual increase in the amorphous phase is observed across various test conditions, which may be attributed to optimization of process parameters such as plasma power, residence time, quenching rate, and particle size.

[0098] This crystallinity-to-amorphous transition captured via XRD analysis provides direct structural evidence of the PTIFR system’s capability to achieve partial to nearcomplete amorphization of quartz feedstock in a single-step, reagent-free, and energyefficient process.

[0099] The following table summarizes key comparative advantages of the Plasma Torch In-Flight method and apparatus versus conventional methods for producing amorphous silica, alumina, and titania. Specifically, the comparison highlights significant improvements in greenhouse gas (GHG) emissions, energy consumption, toxicity of chemical byproducts, and feedstock availability. Regarding product quality, the Plasma Torch In-Flight method consistently yields amorphous silica, alumina, and titania with purity, particle uniformity, and consistency comparable to or exceeding traditional flame hydrolysis and thermal decomposition processes.

[0100] Concerning greenhouse gas (GHG) emissions, the Plasma Torch In-Flight method substantially reduces environmental impact compared to conventional processes. Specifically, emissions decrease from 2.8 kg CO2-eq / kg to approximately 0.4 kg CO2- eq / kg for amorphous silica (an 86% reduction), from 11 .5 kg CO2-eq / kg to around 1 .0 kg CO2-eq / kg for amorphous alumina (a 91 % reduction), and from 5.3 kg CO2-eq / kg to about 0.5 kg CO2-eq / kg for amorphous titania (also a 91 % reduction). These significant improvements directly result from the elimination or substantial reduction of fossil fuel combustion and chemical precursor emissions, thereby strongly aligning with global environmental and sustainability targets.

[0101] With respect to energy consumption, the Plasma Torch In-Flight process achieves remarkable efficiency gains. Conventional processes typically require 11.7 kWh / kg for silica production, 45.0 kWh / kg for alumina production, and 21.5 kWh / kg for titania production. In stark contrast, the Plasma Torch process reduces these figures to approximately 2.7 kWh / kg for silica (a 77% reduction), about 3.5 kWh / kg for alumina (a 92% reduction), and roughly 2.1 kWh / kg for titania (a 90% reduction). These substantial energy savings are attributed to the plasma torch's highly efficient direct electrical-to-thermal energy conversion, significantly surpassing traditional combustion-based methods.

[0102] Additionally, the Plasma Torch In-Flight method greatly reduces toxicity and chemical hazards associated with material production. Conventional processes utilize hazardous chemical feedstocks such as silicon tetrachloride, aluminum chloride, or titanium tetrachloride, resulting in highly corrosive and toxic byproducts such as hydrochloric acid. In contrast, the plasma-based technology employs safer, widely available, and less hazardous feedstocks, predominantly metal oxides or mineral-derived materials, drastically minimizing toxic emissions, chemical byproducts, and associated workplace and environmental hazards.

[0103] Regarding feedstock availability, the Plasma Torch In-Flight process offers a distinct advantage due to its utilization of readily accessible and abundant metal oxides and mineral-based materials, in contrast to conventional methods reliant upon specialized, hazardous, and often more expensive chemical precursors. The broad availability and simplicity of these plasma-compatible feedstocks simplify logistics, reduce raw material costs, and significantly enhance operational sustainability and economic predictability.

[0104] While the above description provides examples of the embodiments, it will be appreciated that some features and / or functions of the described embodiments are susceptible to modification without departing from the described embodiments' spirit and principles of operation of the described embodiments. Accordingly, what has been described above has been intended to be illustrative of the embodiments and non-limiting, and it will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the embodiments as defined in the claims appended hereto.REFERENCES[1] U.S. Patent No. 11 ,447,419 B2[2] U.S. Patent No. 10,457,603 B2[3] U.S. Patent No. 7,288,148 B2[4] U.S. Patent Application Publication No. 2022 / 0234952 A1[5] U.S. Patent No. 10,233,116 B1[6] Chinese Patent No. 104,944,455[7] U.S. Patent No. 3,886,264[8] U.S. Patent No. 9,196,901 B2[9] U.S. Patent No. 9,692,039 B2

[0010] U.S. Patent No. 7,935,329 B2

[0011] U.S. Patent No. 8,137,647 B2

[0012] U.S. Patent No. 8,883,674 B2

[0013] U.S. Patent No. 12,161 ,996 B2

[0014] Frischknecht, Rolf, et al. "Life cycle inventories and life cycle assessment of photovoltaic systems." International Energy Agency (IEA) PVPS Task 12 (2020).

[0015] Assuming a Canadian average for electricity carbon intensity (0. 11 t CO2eq / MWh

Claims

CLAIMS1. A plasma in-flight process for producing amorphous silica, alumina, or titania, comprising the steps of:- generating within the torch system a plasma plume inside the eductor system; injecting crystalline oxide powders, such as crushed quartz, bauxite, or titanium- bearing minerals, into the eductor system; adjusting the angle of crystalline oxide powder injection inside the eductor system to enhance the production of amorphous oxide material - by increasing surface interaction between the feed powder and the plasma plume to enhance the melting rate;- by decreasing the quantity of powder reflected by the plasma plume vortex to improve conversion efficiency; by increasing the residence time of the feed powder within the plasma plume to ensure complete melting;- by minimizing the interference of quench gas with the feed flow to maximize energy transfer;- melting the crystalline particles into a molten phase within the plasma plume;- quenching the molten material at the tip of the plasma plume to form amorphous silica, alumina, or titania particles;- recovering a portion of the amorphous oxide material at the bottom of the reactor system; and- removing the remaining portion of the amorphous oxide material in the form of micro- to nano-sized particles.

2. An apparatus for producing amorphous silica, alumina, or titania, comprising:• a plasma torch system adapted to generate a plasma plume to melt injected crystalline oxide powders inside an eductor system;• a quenching system, wherein gases such as air, nitrogen, and / or argon are injected into the eductor to resolidify the molten oxide into micro-sized amorphous particles;a bottom-mounted collector for recovering a portion of the amorphous material; and• an outlet for allowing the remaining portion to exit the reactor system.

3. The apparatus of Claim 2, wherein a DC arc is stroked between a cathode and a water-cooled anode to generate the plasma plume that flows downward through the eductor to melt the crystalline oxide feedstock.

4. The apparatus of any one of Claims 2 to 3, wherein the anode is water cooled, and wherein water-cooled jacket is provided for cooling the eductor.

5. The apparatus of any one of Claims 2 to 4, wherein the quenching system comprises at least three gas injection ports spaced equidistantly.

6. The apparatus of any one of Claims 2 to 5, further comprising a drop-out box configured to collect micro-sized agglomerates of amorphous silica, alumina, or titania as they exit with the hot gas stream.

7. The apparatus of any one of Claims 2 to 6, further comprising a gas / liquid cooler downstream of the drop-out box to cool the gas stream.

8. The apparatus of any one of Claims 2 to 7, further comprising a fine particle filter, such as a HEPA-type unit, downstream of the cooler for separating residual nano-sized amorphous particles from the gas stream.

9. The apparatus of Claim 2 to 8, further comprising an induced draft fan downstream of the filter for extracting the gas from the system and maintaining sub-atmospheric pressure within the reactor.

10. A plasma in-flight process for continuously producing amorphous silica, alumina, or titania with lower energy consumption and carbon emissions than conventional chemical or carbothermic methods.

11. An apparatus configured to melt crystalline oxide feedstocks and subsequently quench the molten phase to form functional amorphous materials in a single step, without the use of chemical additives or by-products.

12. A plasma in-flight process to convert crystalline SiO2, AI2O3, or TiO2directly into their amorphous phases, avoiding conventional multi-step synthesis and emissions.

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