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Reagent Research Group

The Reagent Research Group was established in 1999 as the Depressant Research Facility with the aim to establish a centre for the characterisation and research of polymeric depressants in flotation. Polymeric depressants are widely used in flotation to depress unwanted gangue minerals such as the talcaceous group of minerals. Owing to the quantity of depressant that is required to achieve adequate results, these reagents often represent the highest reagent cost in flotation operations. This is particularly true for the South African platinum Industry.

It was soon recognised that the effects of depressant action could not be studied in isolation. Thus, the Reagent Research Group came into being at the beginning of 2008 to investigate interactions of the major reagents (collectors, depressants, frothers) in the flotation circuit in an integrated manner.

Research commences at the most fundamental level, where variable parameters are pared down to a minimum in order to understand the specifics of reactions; and proceeds to the applied, where the synergistic and antagonistic natures of the various reagents and minerals are studied.

The current research focus of the facility is the role of depressants in flotation and the synergistic reactions between reagents in flotation systems. Most work is focused on the flotation of platinum group metals.

The Reagent Research Group is able to provide the following:

  • Characterisation of polymeric depressants using current standard techniques

This includes the measurements of molecular weight distribution (as measured using size exclusion chromatography), purity, degree of substitution and viscosity.

  • Development of an additional set of reagent characterisation procedures

These techniques include micro and batch flotation tests, settling tests, zeta potential measurements, chromatography, infrared spectroscopy, microcalorimetry and surface tension measurements. These procedures provide improved ways of evaluating the more subtle characteristics of reagent behaviour and help elucidate the mechanisms involved.

  • The provision of research facilities

This provides the opportunity for both fundamental research – such as that required for postgraduate degrees – and applied research, such as that negotiated with industry to address specific, and in some cases, confidential issues. An annual technical meeting is held to present the latest findings, and to encourage debate and discussion between sponsors and researchers.

Financial support comes from two sources. The core commitment and support comes from the following four mining companies – AngloAmerican Platinum, Impala Platinum and Lonmin Platinum. The second category of support comes from other companies, both reagent users and suppliers who arrange test work and research projects as required.