After the sulphide concentrate has been finely ground, it is then leached under atmospheric conditions in an oxidative leach consisting of interconnected Albion Leach Reactors. The Albion Leach Reactor is an atmospheric leaching vessel that has been designed to achieve the oxygen mass transfer required for oxidation of the sulphide minerals at low capital and operating cost.
Oxygen is injected into the base of the Albion Leach Reactors using Glencore Technology's HyperSparge™ supersonic injection lances. The design of the HyperSparge™ injection system is carried out in conjunction with the design of the agitation system to ensure high oxygen mass transfer rates are achieved in the reactor. The agitator unit power is moderate, and the impeller tip speed is chosen in combination with the HyperSparge™ injection velocity to provide the required mass transfer rates.
The Albion Leach Reactor has a corrosion resistant alloy steel shell and base, supported on a ring beam or raft foundation. The tank aspect ratio is designed to achieve high oxygen transfer rates and capture efficiencies. Glencore Technology has developed fully modular tank shell systems, which can be rapidly installed on site requiring little or no site welding.
The reactor is fitted with a centrally mounted agitator consisting of one or more hydrofoil impellers. HyperSparge™ supersonic oxygen injection lances are mounted circumferentially around the reactor, close to the base, injecting oxygen at velocities in the range 450‒550 m.s-1. High mass transfer rates are achieved within the Albion Leach Reactors.
No internal heating or cooling systems are required in the Albion Leach Reactors. The vessel is allowed to operate at its equilibrium temperature, which is typically in the range 90‒95°C. Heat is provided by the oxidation of the sulphide minerals, with heat lost from the vessel by humidification of off gas. No direct or indirect temperature control is required, simplifying tank construction and maintenance. No external cooling towers or flash vessels are required.