Application Field: Density Control for Refractories and Ceramics
If you’re in the refractory or ceramics industry, you know how critical material density is. Last month, we explored how kyanite is a game-changer for shrinkage control—now, let’s talk about its effects on density to improve the performance and longevity of your refractory.
Why Is Density Control So Important?
Various industries and applications require dense refractories and ceramics to combat chemical corrosion and mechanical stress. Unplanned downtime for repairs can have catastrophic consequences, posing threats to safety, efficiency, and profitability. Engineering your mix to have the appropriate density for your application is a key factor in the performance and longevity of your product.
How It Works
Laser Particle Analyzer
Kyanite’s unique expansion properties make it an excellent tool for density control. When heated, kyanite converts to mullite and expands. While all kyanite expands the same 17% by volume, different sized kyanite crystals impart varying amounts of apparent linear expansion to the ceramic body. This apparent expansion is greater for larger mesh sizes and decreases as the kyanite particles get smaller. We use the different sizes to control where we want the expansion and how we want to use it.
Imagine a crowded room: when larger adults stretch out, people take notice, and some may adjust to make space. But when small children stretch, only those closest to them are aware. Similarly, fine kyanite particles fill the gaps between larger materials. When they are heated and converted to mullite, they expand into the void space between the aggregates in the mix. This expansion reduces the porosity and increases the density of the refractory, making it more resistant to chemical attacks, erosion, and abrasion.
Getting the Mix Just Right
While 4–8% kyanite is typically recommended in refractory mixes, the exact amount will vary based on your materials, operating temperatures, and specific application. Too much kyanite can cause over-expansion and cracking, while too little may leave voids.
That’s where we come in! Our technical experts and cutting-edge R&D team will collaborate with you to create the perfect, tailor-made solution—always confidential and optimized for your needs.
Ready to optimize your mix? We can’t wait to hear from you!
Get in Touch: sales@kyanite.com | +1 (434) 983-2043
Stay tuned for next month’s feature, where we’ll explore a comparatively ‘new’, yet growing application for kyanite—Secondary Mullite Formation!
