Imaging of Silica Sand to Evaluate Its Quality to Use It as Foundry Core Sand

Silica sand is a major mineral commodity for foundries, specifically for sand casting. Suppliers of foundry sand located near consumers would keep costs low production. Gray cast iron in Mexico demands large amounts of silica sand for the manufacture of core molds, currently supplied by the USA. This sand must meet industrial specifications for core sand to reach adequate strength, such as grain shape, grain size distribution, pH and ADV. In the last years, a high demand for silica sand for fracking in the USA has obligated Mexican foundries to search for new sources of this commodity. In this research, seven samples of silica sand from different areas Northeast and Southeast in Mexico were analyzed by microscopy imaging using metallography microscopy and SEM, to compare with core commercial sands. Also, semi-qualitative chemical composition by energy dispersive X-ray spectroscopy was analyzed. Surprisingly, results showed some silica sands from Mexico have textural surface and chemical composition similar to samples from the USA. A source of silica sand located in Mexico could be developed to meet local demand.