Determination of the breakage and wetting parameters of calcite and their correlations

Abstract

This paper presents the breakage and wetting parameters of calcite mineral obtained experimentally and establishes a correlation between these characteristic parameters. The breakage parameter obtained from the different feed sizes of grinding is the specific rate of breakage (S). The wettability parameter, obtained from surface chemistry-based processes such as contact angle measurements or flotation methods, is the critical surface tension of wetting of a solid or mineral (gamma(c)). Calcite mineral, studied for the determination of the above parameters and their correlations, was ground in a laboratory-size ceramic ball mill with dry, wet and chemically aided grindings and tested extensively to determine the gamma(c) values by using a contact angle goniometer and a newly designed micro-column flotation cell. The highest S-i value obtained was 0.35 min(-1) for sodium dodecyl sulfate (SDDS)-aided grinding, and the lowest S-i value was 0.26 min(-1) for dry grinding of the - 600 + 425 feed in the mill. The gamma(c) values for calcite were obtained as 34.0 - 34.9 mN/m for SDDS-treated calcite surfaces, 29.9-31.4 mN/m for sodium oleate-treated surfaces and > 72 mN/m for both dry and wet ground products whose surfaces were not treated chemically. Some correlations were established between the S-i and gamma(c) parameters; as the S-i increases, gamma(c) decreases, indicating that relatively more hydrophobic surfaces are broken faster for the largest sizes, resulting in higher S-i values with more fines (lower gamma of B-i,B-j) in the finer size distribution region (i.e. - 150 mum).