The first stage of the Albion Process™ is fine grinding of the concentrate, which introduces a high degree of strain into the sulphide mineral lattice. The number of grain boundary fractures in the mineral increases, enabling leaching under atmospheric conditions. Fine grinding is carried out in energy efficient IsaMills™.
Fine grinding also prevents passivation of the leaching mineral by products of the leach reaction. Passivation is normally complete once the precipitated layer is 2 to 3 μm thick. Ultrafine grinding of a mineral to a particle size of 80% passing 10 to 12 μm will prevent passivation, as the leaching mineral will disintegrate prior to the precipitate layer becoming thick enough to passivate the mineral.
After the concentrate has been finely ground, the slurry is then leached in agitated vessels, and oxygen is introduced to the leach slurry to oxidise the sulphide minerals.
The agitated leaching vessels are designed by Glencore Technology and are known as the Albion Leach Reactor. The Albion Leach Reactor is agitated using dual hydrofoil impellers and oxygen is introduced to the leach slurry at supersonic velocity to improve mass transfer efficiency and ensure efficient oxidation of the sulphides. The Albion Leach Reactor is designed to operate at close to the boiling point of the slurry, and excess heat generated from the oxidation process is removed through humidification of the vessel off gases.
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Glencore Technology develops, markets and supports technologies for the global mining, mineral processing and metals extraction industries. They have offices in Australia, South Africa, Canada, Chile and Russia, and is a wholly owned subsidiary of Glencore, an international group listed on the London and Hong Kong stock exchanges. For further information please visit the main .