Study of flotation problems by electron paramagnetic resonance

Abstract

1. The degrees of ionicity (covalence) of galena, sphalerite, and hematite have been established by the EPR method. An increase in the proportion of covalent bond between the metal and sulfur weakens the reaction of the water molecules with the mineral surface, thus making some sectors of the surface naturally hydrophobic. 2. The authors give the EPR spectra of copper xanthates, dibutyldithiophosphates, and diethyldithiocarbamates. It is shown that the EPR method enables us to determine the parameters characterizing the probability of the electron-density distribution on the corresponding orbitals and explain the efficiencies of different collecting agents. 3. The nature of the paramagnetic centers of celestite and zircon has been studied. Interpretation of the EPR spectra revealed that the paramagnetic centers are due to electron-hole centers. The flotabilities of celestite, zircon, and barite can be changed by changing the number of paramagnetic centers on their surfaces. The presence of paramagnetic centers on mineral surfaces assists formation of local electric fields of different intensities, which leads to mosaic distribution of the collector on the mineral surface and makes it less hydrophobic. 4. Study of the EPR spectra of coals enables us to establish the rank and degree of oxidation, and their effects on the flotability of coal.