Canadian silica resources:a study of the processing of selected Quebec silica samples for glass and foundry sand

CIM Bulletin, Vol. 80, No. 900, 1987

VINCENT JOURDAIN, DENIS W. ROY, Sciences de la Terre, University du Quebec a Chicoutimi, Chicoutimi, Quebec, and JEAN-MARC SIMARD, Muscocho Exploration, Montauban, Quebec

In cooperation with le Ministere de I'Energie et des ressources, Quebec, le Centre de Recherches minerales, Sainte-Foy, Quebec, and various silica producers, selected deposits of Quebec silica were identified in the southern region of the province and sampled to provide material for evaluation as glass and foundry sand by CANMET. The samples included both sandstone and quartz/quartzite. Head sample analyses ranged from 94.66% to 99.54% SiO2,  0.038% to 0.230% Fe2O3, and 0.16% to 4.51% AI2O3. Impurities included pyrite, iron oxides, and iron staining on quartz grains; carbonates as calcite; and alumina-silicates as clay and/or feldspar. Processing included size reduction to grain size, about 600 turn, by jaw, roll and cone crushers, and grinding in a muller-mixer. Removal of fines was achieved by attrition scrubbing and washing. Further removal of impurities was achieved by reverse flotation of iron oxide and alumino-silicate minerals employing both anionic and cationic collectors. Flotation resulted in a substantial improvement in the quality of most sands, the quartz concentrates analyzing 99.08% to 99.80% SiO2, 0.014% to 0.048% Fe2O3, and 0.06% to 0.49% A12O3. Removal of iron oxide minerals was also investigated using the Sola HGMS. Iron oxide analyses of the non-magnetic fractions were comparable to the iron oxide analyses of the quartz concentrates obtained by flotation, 0.013% to 0.054% Fe2O3. On the basis of the samples submitted, silica from 5 of the 6 deposits studied has potential as source material for glass sand. Foundry tests showed that 3 of the 4 samples submitted for evaluation have potential as foundry sand.

Keywords: Industrial minerals, Silica, Glass sand, Foundry sand, Crushing, Grinding, Magnetic separation, Flotation