The usefulness of a refractory clay depends very much on the quantity of free silica (quartz) in the clay and has to be determined before the clay is mined. It has been found that the quartz content can be correlated with loss on ignition (LOI), Pyrometric Cone Equivalent (PCE), water of plasticity and Bulk Specific Gravity (BSG) and calcining temperature of the clay. All these correlations indicate that a suitable clay should not contain more than 20–25% quartz for refractory use.

C. L. Venable

Papers

Determination of quartz and its correlation with some physical properties of refractory clays (Kaolinite)