Caracterização tecnológica para aproveitamento de matéria-prima sienítica com nefelina

Syenitic rocks with a high nepheline content near Lavrinhas (SP), 234 km northeast of the city of Sao Paulo, may be potentially useful for the production of ceramic products. Based on the mineralogy and texture of this raw material, the best methods of processing these syenitic rocks for fluxing properties are indicated here. In addition, chemical analyses and melting tests were carried out in order to evaluate the melting color before and after magnetic separation, as well as the potential use of this material in glazes and engobes, as compared to a Nepheline standard. Preliminary tests showed that after removal of superficial iron oxide, the raw material bearing nepheline has potential for use in the formulation of porcelain masses, replacing other fluxing materials which have higher added value.