THE BEHAVIOR OF GOLD-BEARING MINERALS DURING FROTH FLOTATION AS DETERMINED BY DIAGNOSTIC LEACHING

The aim of the present paper is to explain the recovery of gold by flo tation as a function of the floatability of liberated and precipitated gold and gold occluded in base metals sulphides, pyrrhotite, pyrite, and arsenopyrite. In contrast with many other studies, the current res earch determines the flotation recovery of each mineral as an integral part of the ore. A further feature of this study is the fact that a s ignificant fraction of the gold is associated with pyrrhotite, so that flotation strategies are aimed at maximising the recovery of pyrrhoti te, which is in contrast with the practice in many similar flotation p rocesses, Quantitative XRD and diagnostic leaching are used to determi ne the distribution of gold between the host minerals as well as the f lotation recovery of each mineral. Optimal sulphide recovery is attain ed by activation with copper sulphate, conditioning with potassium amy l xanthate and nitrogen, and flotation with air. The greatest recoveri es of free gold occurred when oxygen was added during xanthate conditi oning. The recovery of gold bearing sulphides, free gold and refractor y gold will be discussed for each test where oxygen and nitrogen addit ion to the pulp was used. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.