Investigation of the Fundamentals of Nickel Laterite ore Agglomeration Process

  • Mr Ataollah Nosrati, Ian Wark Research Institute, University of South Australia, Australia
  • Prof Jonas Addai-Mensah, Ian Wark Research Institute, University of South Australia, Australia
  • Prof William Skinner, Ian Wark Research Institute, University of South Australia

Despite Australia’s nickel laterite deposits being amongst the largest nickel ore reserves in the world, exploitation via traditional hydrometallurgical process has been difficult. Heap leaching is currently considered as an effective and economic processing pathway for extracting nickel from complex low grade ores. This, however, requires an understanding of the agglomeration process in order to ensure that the optimum agglomerate structure conducive to maximum metal recovery can be engineered. In this study, batch agglomeration behaviour of real nickel laterite ores is investigated to determine the optimum conditions for producing robust granules with desirable size distribution (e.g., 5 – 30 mm). Drum agglomeration of siliceous goethitic nickel laterite ore with focussing on the effect of 30 and 44 % w/w H2SO4 solution binder content (20 – 30%) and water/acid ratio (1.27 vs. 2.33) and batch time (2 – 14 min) on the granules formation behaviour, size distribution and integrity/strength was investigated. The results showed that for both 30 and 44 % w/w H2SO4 solutions, 20 wt.% binder content was the optimum value where robust agglomerates were produced within 8 and < 14 min at lower and higher binder content, respectively. Faster nucleation and granule growth was achievable by increasing either the binder content and/or water/acid ratio. These, however, led to formation of larger but mechanically weaker agglomerates.