High Alkali Ceramic Flux
SPECTRUM®
In ceramics manufacturing, fluxes are essential components that lower the melting temperature required for vitrification and provide the necessary alkalis and alumina to accelerate the transition into the glassy phase during firing. While feldspar is the most commonly used flux in the industry, nepheline syenite serves as a significantly stronger alternative because it contains higher levels of sodium and potassium oxides. Additionally, nepheline syenite delivers higher alumina and lower silica than feldspar, while completely lacking any free crystalline silica.
Covia’s SPECTRUM® high alkali ceramic flux leverages these specific mineral properties, serving as a naturally occurring, silica-deficient sodium-potassium alumina silicate. Thanks to its high alkali-to-alumina ratio and remarkable chemical reactivity, SPECTRUM provides exceptional fluxing power that accelerates the melt and elevates the overall quality of both ceramic bodies and glazes.
Product Highlight
SPECTRUM® ceramic fluxes are produced from nepheline syenite, a naturally occurring, silica-deficient sodium-potassium alumina silicate. The higher total alumina and alkali contribution available from nepheline syenite produces ceramic ware with greater impact and flexural strength and improved resistance to the stresses of thermal extremes and mechanical shock.
SPECTRUM provides a low-melting eutectic—a mineral blend that melts at a lower temperature than the same materials in other proportions—and strong fluxing power, allowing ceramic bodies to mature at mid-fire temperatures suitable for ceramics such as stoneware (cone 3–5 on a cone chart, which measures heatwork, the combined effect of temperature and firing time). SPECTRUM’s high alkali-to-alumina ratio and chemical reactivity speed melting and maturation.
It also accelerates vitrification, forming a dense, glass-like ceramic body across a broad firing range. This supports smooth glazed surfaces at lower temperatures and reduces deformation during fast firing cycles. For greater translucency, SPECTRUM reacts with free crystalline silica, drawing it into the melt to create highly translucent ware.
Mineral:
Nepheline syenite
Product category:
High-Alkali ceramic flux
Applications:
Ceramic ware, enamels and glazes
Increased vitrification rate:
SPECTRUM flux reliably increases the rate of vitrification across a much wider firing range. This property helps to ensure consistently smooth glazed surfaces, even when processed at lower temperatures.
Improved structural strength:
By delivering a higher total alumina and alkali contribution, SPECTRUM significantly enhances the physical toughness of the final ware. This results in a ceramic piece with considerably greater impact and flexural strength and greater resistance to thermal extremes.
Reduced deformation:
Fast fire cycling often introduces the risk of warping or structural failure in ceramic pieces. SPECTRUM helps to mitigate these issues and reduces the deformation that is typically encountered during rapid firing cycles.
Superior translucency:
When highly translucent ware is the objective, this flux is a highly effective additive. It actively combines with and consumes the available free crystalline silica in the body to produce beautifully translucent ceramics.
Stabilized thermal expansion:
Unlike many feldspathic fluxes, SPECTRUM provides high levels of alumina without introducing any free crystalline silica or quartz. This complete lack of free silica is a major advantage that helps stabilize the thermal expansion of the fired product.
Customer Support
Covia’s ceramics team helps customers evaluate materials, solve formulation challenges and improve ceramic performance. With technical expertise across ceramic bodies, glazes and enamels, Covia can help manufacturers assess raw material selection and identify opportunities to improve forming, plasticity, strength and firing behavior.
Through laboratory analysis and application support, Covia works with customers to understand product requirements, kiln conditions and performance goals. That support helps ceramic manufacturers make informed decisions about mineral selection, formulation adjustments and production consistency.
Logistics
The Covia nepheline syenite deposit at Blue Mountain in Ontario, Canada is the source of SPECTRUM ceramic flux. From this site, we offer quality-controlled production, reliable availability and logistics capabilities designed for the needs of ceramic manufacturing.
With SPECTRUM as part of a broader ceramic raw materials portfolio, Covia can help customers with every aspect of their ceramic formulation and production. We are the dependable ceramics partner, featuring high-quality raw materials, aligned with your goal of excellent product quality and delivery time for greater success.
Related Stories
Contact Covia today at 1.800.243.9004 or Sales@CoviaCorp.com, or click to fill out this form.