FloccFines – Flocculation of fine particles in mineral flotation of copper-lead-zinc sulphide ores

Purpose and goal
There are several industrial advantages with a cost and time effective way to evaluate new flocculants in mineral flotation. The main objective of this project was therefore to demonstrate an effective approach to identify potential flocculants for selective flocculation of hydrophilic mineral fine particles. The approach used is based on using a combination of techniques, with focus on measuring interaction forces between hydrophilic mineral surfaces, combined with both flocculation tests of mineral fines and surface chemical characterisation for increased understanding.

Structure and implementation
The project included seven work packages. The aims of WP1–2 were to select materials and study literature. In WP3 preparation tests and characterisation of samples were performed. The procedure on how to perform flocculation tests of fine hydrophilic PbS particles was developed in WP3. Different materials to use in the AFM were tested to get adsorption of depressant. Since the AFM system under the chosen conditions was not robust enough, even with a lot of efforts, the planned work with flocculants in WP4–6 could not be performed. The project results were summarised at the final meeting (WP7).

Expected results
In this project, AFM was evaluated to measure interaction forces between hydrophilic minerals (with adsorbed depressant). Results show that interaction forces can be measured, but the system is not robust enough to add flocculants in a next step, so further method development is needed. In addition, a procedure on how to perform flocculation tests of fine hydrophilic PbS particles was developed. The procedure was optimised for several parameters with the aim to keep the hydrophilic fines in dispersion long enough before settling, to be able to detect the effect when adding flocculants.