Froth flotation: preparation of a laboratory standard

In evaluating the separation of coal from slurries of fine solids by froth flotation, it is necessary to work to a standard method to ensure that the procedure, on the same sample, can be repeated by others and the same resul ts obtained. In a number of countries the standard procedure is produced an d distributed by the International Standards Organisation (ISO) working thr ough its member countries. In the preparation of a froth flotation standard , two different techniques from two countries (Australia and Great Britain) have been proposed. These procedures, known as the 'tree' and 'release' an alyses respectively, differ in the laboratory technique and presentation of results. In order to assist in the debate of which of the procedures shoul d be adopted as the basis for the International Standard, a short programme of comparative work was undertaken to evaluate the different methods. Samp les of coal slurries from Australia, Great Britain and South Africa were ev aluated using the Australian and British procedures. The work undertaken is described detailing the preparation of the samples, test procedures and differences between the two techniques. The results sho wed that the two techniques produced similar results with the 'Release Anal ysis' giving more detail at the cleaner (low ash) end of the curve and the 'Tree Analysis' more data for the middle (medium ash-higher yield) part of the curve. The results indicated that the technique chosen would be depende nt upon the information required from the flotation analysis, i.e, the Brit ish 'Release Analysis' for the cleaner coal data and the Australian 'Tree A nalysis' for higher ash fractions. (C) 1999 Elsevier Science Ltd. All right s reserved.