Processing of Nickel Ores and Concentrates ’12, the 3rd in the series, was held at the Vineyard Hotel, Cape Town, from November 14-15, 2012.
Sponsored by Nalco Africa, the conference was attended by 35 delegates from eight countries. These are the smallest of MEI’s conferences, but they always attract high quality audiences and papers.
Nickel-bearing ores are seldom in the league of mega-tonnage such as occur in the porphyry copper deposits. The scale and life-of-mine of nickel operations are thus much more limited, and one has to maximize the asset worth by processing efficiency rather than volume. Whereas the nickel market has started to stabilize after the recession of 2008/9, it will be a while before we see the record highs of a few years ago when the metal price peaked at $25/lb. Although nickel operations are often complemented by other payable metals such as copper and the platinum-group elements, under the current market conditions, every gain that can be sustainably made on recovery and grade enhances the business case. It is intended that the conference will attract contributions from experts around the world, to provide a forum for discussion of common problems and possible performance opportunities.
The aim of this conference is to bring together researchers and plant operators, to discuss all aspects of the physical and chemical processing of nickel ores, copper-nickel ores and laterites, and nickel concentrates, including:
- Froth Flotation and other beneficiation methods
- Bio and Hydrometallurgy
- Environmental aspects of nickel processing and smelting
Wednesday November 14th
Todays sessions focused on the processing of nickel laterites. Although future supplies of nickel depend on laterite ores, their processing is inherently energy intensive and expensive as, unlike sulphide ores, they cannot be significantly upgraded, meaning the entire ore needs to be treated in the process. Innovative technologies are being developed that are attempting to address the current processing issues, including some that are in their early stages of development.
The conference got off to a great start with an excellent keynote lecture by Anne Oxley of Alyssum Ventures, UK and Nic Barcza (South Africa) on the integration of hydro and pyro processes in the processing of nickel laterites.
Hydrometallurgical process routes are seen to be the future for treatment of the lower grade nickel laterites ores. Hydrometallurgical projects of recent years have focused on HPAL and have been largely unsuccessful economically, with huge capital cost overruns. The simplest and least capital intensive of the possible alternatives to HPAL is atmospheric heap leaching. Development work is also underway by several companies into atmospheric tank leaching which is also a potentially viable alternative. The natural product for a leaching process is a high grade nickel intermediate either from a direct precipitation process (containing approx. 36% Ni) or via Ion Exchange (>50% Ni).
There are many existing pyrometallurgical facilities which could easily be adapted to take this nickel intermediate giving them significant potential benefits especially as raw ore grades diminish. The nickel production from these plants could also be increased and for new plants large capital and operating cost savings achieved. There are also potential environmental benefits with much less energy consumed and lower greenhouse gases emitted per tonne of nickel produced. In the future an integrated hydrometallurgical plant with attached existing smelter or a more advanced pyrometallurgical smelting process (e.g. a DC Arc Furnace) could well be the way forward for new projects.
Following the keynote were seven papers on laterite processing, from Canada, Australia, South Africa and UK. These included a paper on the direct reduction of nickel and iron from laterite ore using the Carbonyl Process, which was invented over 100 years ago. The Canadian company CVMR Corp. has developed the process of direct extraction of nickel and iron from laterite ores in the form of metal carbonyls and production of pure metals. The technology has been applied to several types of Limonite and Saprolite ores containing additional metal values such as Copper, Cobalt, PGE and REE.
If you want more infomation, please visit the official website of the Nickel Processing ’12 .