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:: Implats Successfully Commissions Mintek Technology
Mintek has successfully installed and commissioned the latest version of its Atomijet atomiser for Impala Platinum Refineries in Springs.
The custom-designed unit is a batch caster with a 50 kg capacity, developed specifically for atomising small batches of precious and other metals in situations where accountability is important.
The Atomijet employs induction heating to melt the charge, and three high-pressure water nozzles to impact on the stream of molten metal, transforming it into fine powder. Control of the pour is automated to ensure consistent results. "The technology is similar to normal atomising, but is more cost-effective", said Nick Maritz, manager of Mintek's Engineering Services Division. “The particles of the product produced by the Atomijet are somewhat coarser than those from a normal atomiser ? 90 per cent smaller than 300 micrometres (µm) as opposed to from about 40 µm to 70 µm, which is much finer than needed for some applications."
The Atomijet was originally developed as an adjunct to Mintek's MinataurTM all-hydrometallurgical gold refining process, in which it is used to prepare atomised gold for leaching. The unit at Impala is a second-generation machine featuring a number of improvements. "Specifically, the melting head and the atomiser cup have been separated, each with its own independent induction heating coil", explained Maritz. "This enables greater operating temperatures to be attained - in excess of 1 600°C, compared to about 1 100°C with the earlier models. This extends the range of materials that can be processed."
The complete R2.2-million unit, consisting of the atomiser itself, plus power supply and other ancillary equipment, was installed on a turnkey basis, and has been running at Impala since August. "This process has performed to design, and has been used to enhance the refining efficiencies of certain secondary materials", said Ricardo Tabilo, assistant shift chemist of projects at Impala. "The net result is a reduction in the secondary precious metal pipeline and a lower metal inventory in process at any one time."
Before being installed, the Atomijet was tested at Mintek for atomising a variety of precious, base, and ferrous metals. "Now that the technology has been proven in industry, we are confident that the Atomijet can be marketed more widely for general atomisation duties in different sectors of the industry", concluded Maritz. "Apart from improved robustness and reliability, the quality of the product from the new Atomijet is much more consistent than that from the previous model".
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