Clean processes and the influence of fine grinding

IM’s Clean Process feature in the May issue examines advances in mineral processing that reduce both chemical and energy use. New technologies in fine grinding offer substantial energy savings and AMIRA project P1003 seeks to provide the hard data which would enable companies to make decisions on which of these new technologies is most appropriate for them and what improvements they might expect. A series of recent papers has described the greater energy efficiency of mills such as Xstrata’s IsaMill and the Stirred Mill Detritor compared with ball mills or even tower mills. The potential to capture and extend these savings would appear to be significant.

Accordingly, P1003 will explore:

  • Impact of fine grinding with non-reactive media on flotation chemistry
  • Enhanced liberation resulting from finer particle size distribution (PSD)
  • Use of IsaMill and SMD for coarser tertiary grinding, with coarser F80 feed PSD
  • Benefits of the fine grinding narrower product PSD.

Surface preparation of particles plays a key role in fine and coarse particle recovery and enhanced selectivity. New IsaMill and SMD grinding technology has advanced mechanical surface cleaning of minerals to relatively coarse particle size applications.

Also, opportunities exist to improve liberation of cleaner feed without harmful chemistry (achieving better than traditional grades that improve smelting throughput) and to reduce primary grinding on high tonnage streams and do more regrinding on rougher and scavenger concentrates. These would achieve lower overall energy consumption by inert regrinding.

This will be a collaborative project involving University of British Columbia, McGill University and the Ian Wark Research Institute of University of South Australia. It is proposed that it be jointly funded by two supplier sponsors, six generic sponsors and two case study sponsors. Expressions of interest are now being sought. (Contact: [email protected])

This would be a three year project. It is proposed that case study sponsors each contribute AUD$190,000 a year and generic sponsors AUD$95,000 a year. Supplier sponsors would each contribute AUD$56,000 a year.