Dry Grinding has the obvious advantage of reducing the water consumption, and hence the amount of wastewater produced in mineral processing operations. It also gives less wear of grinding surfaces and media compared with wet grinding. Presently dry grinding is used in cement production, but the wider adoption of dry grinding is of interest to reduce the water consumption in mineral processing. There are several barriers to wider adoption of dry grinding, compared with wet grinding:
- A higher specific energy consumption, of about 20-25%
- Lower volume throughput capacity (meaning larger equipment is needed)
- A wider particle size distribution (both coarser and finer particles)
- Possible effects on downstream processing (such as less efficient separation in flotation)
- Spreading of dust (which wet processing helps to suppress).
Nevertheless dry grinding has been identified as a potential technology for the future, and was selected as the topic for a PhD study by Vitalis Chipakwe, partly supported from the SEESIMA project. The results have been reported in a Licentiate thesis, and subsequently in the PhD thesis, as well as in a series of journal articles. A summary of this work is provided here.