Vitrified composite novaculite and process for producing same

摘要

A process for artificially producing a relatively high density, vitrified composite novaculite product of relatively homogenous, characteristics with a MOH hardness of between 7.0 and 8.0, and the artificial stone product thereby produced. First a supply of dry abrasive comprising at least 95% by weight silicon dioxide is supplied. This source preferably includes mixtures of 100 mesh novaculite powder and 200 mesh novaculite powder. The dry abrasive mixture is thereafter mixed with a wetting agent, such as a 16:1 mixture of liquid organic concentrate and water, a temporary binder, calcium stearate, and a high refractory frit. The resultant mixture is thoroughly blended to form a first intermediate mixture having a weight of approximately 64% of said dry abrasive, 5.72% of a temporary binder, 3.08% of the wetting agent approximately 1.98% calcium stearate, and approximately 24.3% frit. The intermediate mixture is then subjected to gyratory screening yielding a second intermediate mixture which is then blended with a ball clay to provide a final mixture, which, after final screening, is suitable for cold pressing and subsequent vitrification. Preferably the final mixture consists of approximately 91.56% of the second intermediate mixture and 8.5% of the tennessee ball clay. The final mixture may be pressed in the shape of the desired end product at five tons per square inch. Vitrification is achieved by firing the pressed parts in an electric furnace up gentle ramps to slowly approach cone 04, and a soak time of approximately 2 hours is preferred.