How is spodumene used in ceramic heat-resistant cookware?
Spodumene is first calcined to 1150°C (0.5 – 1.0 hr soaking) to convert it to β-spodumene. It is important to note that, during the calcination process, spodumene increases its volume by 30%. Thus it is necessary to keep an allowance for this expansion when calcining spodumene, for example, by filling a refractory sagger to less than 50% of its volume. Generally, the body contains 40-50% β-spodumene and the balance is a ball clay and kaolin. If it is to be glazed, then the glaze may contain 50-60% β-spodumene in order to match the coefficient of thermal expansion of the body.
