A study of the thickening process for fine tailings of gold-bearing ores

Abstract

Refractory low-grade gold-bearing ores require deep processing with finer preliminary grinding. As a result, finely dispersed products are formed, including fine tailings, which raise particular environmental concerns. The article presents the results of experimental thickening studies for the concentration tailings of gold-bearing ores from the Yuzhno-Nevyanskoe and Panovskoe deposits. The material studied is distinguished by the presence of fine clay inclusions, which reduce the sedimentation rate of slurry solids. The main processing methods are gravity separation in centrifugal concentrators and flotation. Electrokinetic properties of the particle surface, in particular, the x-potential, in the tailings slurries entering the thickening process may be used to predict thickening performance with sufficient accuracy and significantly reduce the number of laboratory experiments. Measured values of the x-potential, electric double layer thickness, and other dielectric properties of the particle surface were used to establish that the most effective sedimentation of the tailings was achieved at a mass fraction of solids in the slurry of up to 25 % and a pH value of at least 10.5. The optimal flocculant feed amount required to increase the slurry sedimentation rate was also established. It is therefore recommended to use the following flocculants for the ore processing tailings of the Yuzhno-Nevyanskoe deposit: Praestol 2510 at more than 10 g/t and Magnaflok 10 at over 20 g/t. Flocculants are not required for thickening the ore processing tailings of the Panovskoe deposit.