Relations between the size distribution of a gold particle system and the leaching curve in cyanide solutions

In a leaching solution at a constant stirring rate, a system of solid particles dissolves at a rate dependent on reagents concentration and temperature. In consequence, if these two variables are keep constant throughout the dissolution process, the variations in the slope of the plot of the dissolved gold mass, or the fraction reacted versus time, are caused only by the decrease in the solid surface area caused by the dissolution process. This variation in surface for a gold particle system comprising only plate particles, allows us to establish the size distribution frequency from the slope of the curve of the gold mass dissolved versus time. In this paper a method to establish the size distribution of a gold particle system from the leaching curves in cyanide solutions is deduced. The size distribution, calculated from the fraction reacted versus time curve, compares well with the distribution found by measuring the particles using electron microscopy. The method allows us to establish the size distribution of systems comprising very small particles. Copyright (c) 1994 Elsevier Science B.V. All rights reserved.