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Homogenization phenomena of surface components of fluorite and calcite

Sun Ruofan, Liu Dan, Zhang Benyue, Lai Hao, Wen Shuming

Physicochemical Problems of Mineral Processing

2021

Vol. 57, iss. 1

250--258

The flotation separation of fluorite and calcite poses one of the most difficult problems in the mineral processing industry. In particular, the surface homogenization of fluorite and calcite worsens the result of fluorite flotation. In this paper, time of flight secondary ion mass spectrometry and principal component analysis are used to study the surface homogenization of fluorite and calcite during grinding and in solution using X-ray photoelectron spectroscopy, infrared spectroscopy, and solution chemical calculations. The results show that the surface composition of calcite converts to fluorite after mixed grinding and that the surface composition of fluorite also converts to calcite in clarified calcite solution.

Water contact angle on corresponding surfaces of freshly fractured fluorite, calcite and mica

Kowalczuk P. B., Akkaya C., Ergun M., Janicki M., Sahbaz O., Drzymala J.

Physicochemical Problems of Mineral Processing

2017

Vol. 53, iss. 1

192--201

Advancing and receding contact angles of water with corresponding surfaces of freshly fractured calcite, fluorite and mica were measured. The corresponding surfaces were obtained by mechanical splitting of a small lump of each mineral into two pieces. Theoretical considerations revealed that depending on the mineral cleaving plane, surfaces created by splitting into halves can be either identical or entirely different as far as their surface chemical composition is concerned. It was experimentally established that receding and advancing contact angles measured on the corresponding surfaces of fluorite, calcite and mica were identical for the sessile drop method. When the contact angle was measured by the captive bubble approach, there were small differences in the contact angles measured on the corresponding surfaces of fluorite. It was most probably due to surface irregularities and roughness, and therefore different times needed to rupture the liquid film between the bubble and solid surface.

Characterization of Cu-Ni alloys by temperature-programmed reduction method

Zieliński J.

Polish Journal of Chemistry

1998

Vol. 72, nr 12

2621-2628

Reduction of surface oxide preformed on unsupported and alumina supported Cu-Ni alloys was examined at a linearly increasing temperature. The obtained TPR spectra exhibited two peaks of H2 consumption, connected with the reduction of surface copper and surface nickel oxides. The size of these peaks was used to estimate surface compositions of the alloy. The results obtained agree with the surface composition calculated from a semiempirical equation.