Visual presentation of the correlation between solid (mineral) surface free energy and its wettability by flotation tests using the Hallimond tube

Abstract

This paper presents earlier published results, as well some new ones, of the flotation tests carried out with the help of a Hallimond tube for several different apolar and polar minerals. This is to depict the relationship between mineral surface free energy and its flotability. Although the thermodynamic condition for the efficient flotation of a mineral is well known, this paper prompts the not-acquainted readers to get familiar with the fundamental thermodynamic relationships involved in the wetting processes and to learn about usefulness of the simple flotation experiments for this purpose. This relationship between the flotation recovery of a mineral and the work of water spreading on the mineral surface is clearly illustrated. The work of spreading is the difference between the work of adhesion and the work of water cohesion. This work has to be negative to carry out an efficient flotation of a mineral sample. Thus, the purpose of this paper is to show that the simple Hallimond tube is a very useful tool for studying solid (mineral) surface hydrophobic/hydrophilic character under the kinetic conditions.