Engineered Mineral Performance. Delivered with Precision.

Our continuous production process operates at high temperatures across different stages, depending on the target product specification:

For bulk density and structural transformation: Raw kaolin is subjected to controlled thermal treatment at 1450°C to 1500°C, inducing complete dehydroxylation and the formation of mullite and other high-temperature phases, resulting in a dense, thermally stable material with a bulk density of 2.42 g/cm³.

For apparent porosity control and PCE performance: The process runs at 1550°C to 1600°C, promoting complete mineralogical transformation and achieving an optimal apparent porosity of 6–7%.

This precise temperature management throughout our continuous process is what gives our calcined kaolin clay its superior mechanical strength, thermal resilience, and chemical stability.

Our rotary kiln is fired using petroleum coke (pet coke) — a high-carbon, high-calorific fuel that delivers the intense and sustained heat required for our high-temperature calcination process. Pet coke enables us to consistently achieve and maintain the precise temperatures needed across our continuous production process, ensuring uniform mineralogical transformation and reliable product quality at every stage.

Mullite formation is a defining feature of our high-temperature calcination process, and it is what gives our calcined kaolin clay its outstanding refractory performance. The process unfolds in the following stages:

Stage 1 - Calcination and dehydroxylation

Raw kaolin clay, rich in kaolinite, is fed into the rotary kiln and subjected to high temperatures of 1550°C–1600°C. During this stage, kaolinite undergoes dehydroxylation — the removal of hydroxyl groups from its molecular structure — converting it into metakaolin, a highly amorphous and reactive intermediate phase.

Stage 2 - Structural reorganization

As temperatures rise further, the metakaolin phase becomes unstable. The alumina (Al₂O₃) and silica (SiO₂) components within it begin to reorganize at a molecular level, driven by the sustained thermal energy of the continuous process.

Stage 3 - Nucleation and growth of mullite

Through this structural rearrangement, mullite (3Al₂O₃·2SiO₂) nucleates and grows as a stable crystalline phase. The proportion and morphology of the mullite crystals formed depend on the calcination temperature and duration — both of which are precisely controlled throughout our continuous production process.

Stage 4 - Formation of the final microstructure

The resulting material contains mullite crystals embedded within a glassy matrix. This microstructure delivers the hallmark properties of high-performance calcined kaolin clay — a high melting point, low thermal expansion, and outstanding resistance to thermal shock and chemical corrosion — ensuring refractory linings maintain their structural integrity even in the most extreme industrial environments.