High-purity nanoscale spherical silicon micropowder for refractory castables

High-purity nanoscale spherical silicon micropowder for refractory castables

The high-purity nano-spherical silicon micropowder for refractory castables is refined through an innovative and advanced process method, yielding a stable and narrowly distributed particle size with an exceptionally large surface area and uniform particle distribution. It is a spherical silica micropowder with a spheroidization rate of approximately 95%, exhibiting excellent chemical resistance, weather resistance, insulation properties, reinforcement capability, and thermal stability.

Our spherical silicon micropowder is manufactured from premium fused quartz or crystalline quartz raw materials through specialized processing. This high-strength, high-hardness, inert spherical granule features a SiO2 content exceeding 99.9%, with a whiteness of 95-98%, density of 2.2, Mohs hardness of 6.0, and fineness ranging from 0.2μm to 0.5μm. It exhibits a precisely controlled particle size distribution and appears as a white powder.

High-quality spherical silicon micropowder exhibits exceptionally low oil absorption, mixing viscosity, and friction coefficient. Its unique spherical structure, compared to angular quartz powder (silicon micropowder), ensures superior powder flowability. The resulting powder exhibits a small angle of repose, enabling dense compaction when mixed with organic polymer materials to enhance structural strength. Additionally, it demonstrates excellent dispersibility, uniform mixing, and significantly improves material flowability.

It is widely used in CCL, EMC, electronic adhesives, plastics, films, polishing, special ceramics, inks and coatings, and cosmetics. As a filler, spherical silicon micropowder can greatly improve the rigidity, wear resistance, weather resistance, impact and compression resistance, tensile strength, flame resistance, arc insulation characteristics, and UV radiation resistance of electronic products.

2. Characteristics of nano-scale high-purity spherical silicon micropowder:

1. High purity: Our innovative purification technology ensures products reach 99.9% purity across all applications, meeting stringent requirements for silicon micropowder in high-tech fields.

2. The sphericity is good, the sphericity rate is high, the surface is smooth without holes, and the specific surface area is small.

3. With a large surface area, it exhibits excellent thixotropy, providing superior reinforcement and thickening effects. Additionally, it can undergo targeted surface treatment and encapsulation for different systems used by customers, resulting in enhanced hydrophobicity and oleophilicity. This makes it suitable for applications in coatings, glass surfaces, electronic packaging, and other fields.

4. Small particle size: Nanoscale controllable particle size control technology meets the technical requirements of product application departments for micronization and density adjustment. The particle size is controllable within 0.2μm-10μm, with uniform distribution, large specific surface area, high surface activity, and low bulk density.

5. Advanced spheroidization technology: The mature, stable, and reliable spheroidization process elevates the sphericity of silicon micropowder to over 95%, with uniform morphology and smooth surface.

6. Low radiation: Uranium content <0.5 ppb; Heat resistance up to 1500°C or higher.

3. Technical specifications of nano-scale high-purity spherical silicon micropowder:

4. Scope of Application:

u cosmetic additives such as lipstick, powder compact, eyeshadow, BB cream, and foundation

u Copper-clad laminates, electronic adhesives, potting compounds, functional plastics, rubbers, epoxy resin castings, LED encapsulation materials, etc.

u filler for semiconductor tip molding

u High-performance ceramics, nano-ceramics, composite ceramic substrates

u powder coating

u absorbing material

u plastic film anti-adhesion material

u filler for precision injection molding

u raw material for ceramic sintered products

u polishing powder

u wax packing

u dental material

u rubber modification, sealant ceramic toughening, binder modification, functional fiber additives, plastic modification, anti-paint aging additives;

u Polymer: Enhances the thermal stability and anti-aging properties of polymers

u The color rubber products with a small amount of nano-SiO2 added in the solution-polymerized styrene-butadiene and chlorinated polyethylene have the same or better toughness, strength, elongation, bending resistance, UV aging resistance and heat aging resistance as EPDM.

u The problems of poor suspension stability, poor thixotropy, poor anti-aging and poor smoothness are solved by adding a small amount of nano-silica to the traditional coatings.

V. Application Analysis of Nano High-Purity Spherical Silicon Micropowder in Refractory Castables:

Nano-pure spherical silicon micropowder serves as both a key additive in refractory castables and an essential component in refractory materials. Its incorporation enhances the fluidity of castables. With its small particle size and spherical morphology, silicon micropowder readily penetrates micro-pores in refractory mixtures. This not only demonstrates excellent water-reducing properties but also improves material density and reduces porosity, ultimately enhancing the structural strength of refractory castables.

The mechanism of action is relatively complex, generally attributed to the combined effects of filling and coagulation. As a type of shrinkage inhibitor, it can mitigate or prevent shrinkage in refractory materials during heating and use after molding. Traditional refractory castables feature a graded mix of refractory aggregates and powders. Although they exhibit high bulk density and compact structure, excessive water still fills numerous pores. After water removal, many pores remain. When silicon micropowder is added, these pores are filled by the micropowder, with only a minimal amount of micropores remaining filled by water. This reduces the mixing water content in refractory castables. After water removal in the molded body, fewer pores remain. In other words, adding silicon micropowder decreases mixing water usage while improving bulk density, reducing apparent porosity, and enhancing castable fluidity. The compressive strength of refractory castables with silicon micropowder also shows significant changes at different temperatures. Initial strength occurs at 110°C, intermediate strength at 1100°C. Due to the fine particle activity of SiO2 micropowder and the fluxing effects of CaO and other impurities in the castable, strong ceramic bonding is formed. At high-temperature strength of 1450°C, silicon micropowder reacts with alumina micropowder to form mullite, further reducing porosity and improving high-temperature strength.

The incorporation of silicon micro-powder in refractory castables serves to fill microscopic pores, with the precise particle gradation of ultra-fine powder enhancing the material's strength properties. When SiO2 is combined with appropriate dispersants in castables, the spherical morphology of silicon micro-powder facilitates its penetration into micro-pores. Its small particle size not only demonstrates excellent water-reducing effects but also improves the density of refractory castables, reducing post-drying voids and porosity, thereby enhancing both strength and high-temperature performance. Concurrently, active silicon micro-powder forms colloidal particles in water, which adsorb dispersants to create a solvent layer, thereby improving fluidity and forming characteristics. Additionally, due to its fine particle size, high surface free energy, numerous lattice defects, and high reactivity, silicon micro-powder readily undergoes solid-phase sintering reactions at medium-high temperatures and mullitization reactions with AL2O3 in high-alumina refractory materials, significantly improving the post-burn strength and high-temperature performance of low-cement refractory castables.

VI. Overview of Characteristics and Applications of Nanoscale High-Purity Spherical Silicon Micropowder:

Nanometer-scale high-purity spherical silicon micropowder is a vital functional inorganic material characterized by chemical stability, acid and alkali resistance, an exceptionally large specific surface area, well-developed pores, high surface activity, superior oil absorption, strong thickening properties, high-temperature resistance, excellent electrical insulation, and UV resistance. Its unique spherical structure endows the synthesized materials with physical and chemical properties unmatched by conventional materials. These properties enable not only the enhancement of traditional materials but also the development of novel materials. Examples include high-strength, ultra-hard, high-toughness, and superplastic materials; insulating and electrode materials; superconducting materials; specialized low-temperature sintered refractory materials; and advanced thermal exchange materials.

The chemical inertness and unique thixotropic properties of this compound significantly enhance the tensile strength, tear resistance, and wear resistance of rubber products, with the modified rubber exhibiting tensile strength increased by several dozen times. It serves as an additive for controlling the rheology and thixotropy of liquid systems, adhesives, and polymers, as well as for anti-settling, thickening, and anti-sagging applications. Additionally, it functions as a reinforcing agent for HCR and RTV-2K silicone rubbers, and can be used to regulate free flow and as a anti-caking agent to improve powder properties.

For this reason, nano-scale high-purity spherical silicon micropowder has become a powder material with broad applications and increasing market demand. It is now widely used in rubber, coatings and paints, electronic packaging materials, silicon-based substrates, functional chemical fibers, functional plastics, advanced ceramics, special refractory materials, sealants, adhesives, as well as in chemical, pharmaceutical, and pesticide industries.

VII. Application Analysis of Nanoscale Spherical Silicon Micropowder in the Cosmetic Industry:

It is well known that cosmetics require strong ultraviolet (UV) shielding capabilities, preferably capable of protecting against both the harmful effects of ultraviolet medium-wave (UVB) and ultraviolet long-wave (UVA) radiation on the human body. Essentially, UV shielding involves two aspects: the absorption of UV radiation mentioned earlier, and the reflection of UV radiation.

Traditional sunscreen formulations predominantly employed organic compounds as UV absorbers. However, excessive usage to maximize UV protection has been associated with increased risks of skin cancer and chemical allergies. In contrast, nano-scale high-purity spherical silicon micropowder, as an inorganic component, demonstrates excellent compatibility with cosmetic formulations. It is non-toxic, odorless, and free from the aforementioned issues. Its inherent whiteness allows for simple coloration. Notably, this material exhibits exceptional UV reflection capability and remarkable stability—remaining undecomposed, uncolored, and chemically inert upon UV exposure. These outstanding properties establish a robust foundation for the advancement of next-generation sunscreen cosmetics.

l Nail enamel

In nail polish formulations, silica ensures even pigment distribution within the gloss agent, prevents pigment settling, and provides rheological properties to enhance application. When the solvent system's refractive index matches silica's (1.48), transparent formulations like base and top coats can be achieved. Otherwise, high concentrations may cause matting effects that reduce desired gloss. Both hydrophilic and hydrophobic silica products are suitable for nail polish, with concentrations recommended between 0.25% and 4.0%.

l lipstick

In lipsticks, silica dioxide (SiO2) ensures uniform pigment distribution and significantly enhances thermal stability, preventing softening upon temperature rise. After application, it prevents the lipstick from penetrating fine lip lines and causing smudging, thereby maintaining long-lasting color retention. However, higher concentrations may reduce glossiness.

l Eye care

Many eye and facial cosmetic products, including blush, foundation, lipstick, mascara, and eyeliner, can achieve the desired properties and necessary stability through the use of silica alone. Silica serves as an efficient anti-caking agent and free-flowing agent, enhancing storage stability and the dispersibility of powdered products. It also enables the use of pigments in cosmetics, particularly in high-solid formulations. Finally, silica functions as an effective processing aid for grinding and filtering powders.