Current Production Status of Fused Silica And Its Applications in the Refractory Industry

Current Production Status of Fused Silica and Its Applications in the Refractory Industry

Production Status of Fused Silica

Fused silica generally includes two types: transparent quartz glass and opaque quartz glass. Transparent quartz glass contains over 99.95% SiO₂ and is produced by melting high-purity quartz powder or silicon tetrachloride at high temperatures. Opaque quartz glass, with SiO₂ content exceeding 99.80%, is made from common quartz powder and sand through high-temperature melting. The current production status of fused silica is characterized by the following:

• Broad Application Fields:
  With technological advancements, fused silica’s application range has expanded rapidly, encompassing products like high-purity, high-temperature quartz glass tubes, high-purity coated crucibles, quartz glass for optical communications, and quartz glass for laser applications.

• Significant Production Challenges:
  There are two major challenges in fused silica production: the high melting temperature and viscosity make bubble removal difficult, and achieving superior performance requires ultra-high purity, with impurity levels below 0.01%.

• Insulation and Energy Consumption Issues:
  SiO₂’s high melting temperature and reactivity with other substances, leading to silicate formation, pose a technical challenge in selecting insulation materials that do not react with fused silica. In China, fused silica production primarily uses self-insulation, utilizing unmelted quartz for insulation to avoid contamination from refractory materials. However, the effectiveness of this method is limited, often resulting in furnace shell overheating, high energy wastage, low yield, and quality challenges. Fused silica production is energy-intensive, with electricity accounting for over 50% of production costs.

Applications in the Refractory Industry

In the refractory industry, fused silica has several applications:

• As a Raw Material for Refractory Materials:
  Fused silica’s excellent high-temperature and corrosion resistance make it an ideal raw material for manufacturing linings and protective layers in various high-temperature furnaces.

• Enhancing Refractory Material Properties:
  Mixing fused silica with other refractory materials can improve overall properties, such as increasing refractoriness and reducing thermal expansion coefficients.

• Optimizing Refractory Production Processes:
  Fused silica can help optimize production processes by reducing costs and improving efficiency.

Specific applications in the refractory industry include, but are not limited to:

• Steel Smelting:
  Fused silica is used to manufacture refractory bricks for blast furnaces and hot blast stoves, enduring high temperatures, pressure, and corrosive conditions.

• Glass Manufacturing:
  Fused silica serves as a lining material in glass furnaces, withstanding high temperatures and erosion by molten glass.

• Ceramics Manufacturing:
  It is used in kiln linings and protective layers for ceramic production, ensuring product quality and efficiency.

In summary, fused silica has broad and critical applications in the refractory industry. With continued technological advancement and industrial growth, the applications and market demand for fused silica are expected to expand further.