LATEST IMPROVEMENT FOR HIGH PRESSURE ACID LEACH PLANT OPERATION OF CORAL BAY NICKEL CORPORATION

摘要

The High Pressure Acid Leach (HPAL) Plant for nickel-cobalt mixed sulfide production at Coral Bay Nickel Corporation (CBNC) in the Philippines has been in operation since 2005 with a capacity of 10,000 Ni-t/year. Subsequent to the commissioning of the second plant in 2008, the production capacity has increased to 22,000 Ni-t/year (Llerin et al., 2011). CBNC's annual nickel production reached more than 24,000 tons of nickel in 2014. The concepts to achieve this capacity are the high availability and the reciprocally flexible operation of both plants. The availability depends on some factors, such as the control of impurities in the process and the equipment condition, to mention a few. In the HPAL process, we continue to try to adjust ORP and acid concentration in the autoclave based on the impurities such as iron and magnesium in the feed ore. It is important to control these impurities by the temperature, ORP, and acid concentration to maintain the high operation availability.This paper presents the general HPAL process and the behaviour of impurities in the HPAL process.