Nowy Swiat 67, 00-046 Warsaw, Poland. To whom correspondence should be addressed. In this paper, we present our method for the measurement of contact angles on the surface of minerals during the bioleaching process because the standard deviation obtained in our measurements achieved unexpectedly low error. Construction of a goniometer connected with a specially prepared computer program allowed us to repeat measurements several times over a short time course, yielding excellent results. After defining points on the outline of the image of a drop and its baseline as well of the first approximation of the outline of the drop, an iterative process is initiated that is aimed at fitting the model of the drop and baseline.
Copper sulphides are hydrophobic, have a high surface energy and a negative surface charge.
The method of measuring contact angles between liquid and non-homogenous solid surfaces was developed and is described below. The bacteria were isolated from post-flotation wastes in the course of copper bioleaching research. The sulphur plate was prepared by heating elementary sulphur and then making a thin smooth cast. The plate of ore was made from a thin section of crude ore by polishing. The surface of the ore plate was washed in ethyl alcohol and water.