The Direct Leaching of Nickel Sulfide Flotation Concentrates-A Historic and State-of-the-Art Review Part II: Laboratory Investigations into Pressure Leaching

The following review is the second part of a series concerned with the direct hydrometallurgical processing of nickel sulfide flotation concentrates. In the first part of this series, piloted leaching processes and commercial nickel sulfide operations which employed direct hydrometallurgical processing were comprehensively reviewed. In Part II of this series, laboratory investigations into the pressure leaching of nickeliferous sulfide concentrates are critically analyzed. From this review, it is apparent that sulfuric acid pressure leaching processes have received the most attention relative to other lixiviant systems such as ammonia/ammonium, chloride, and nitric acid. This is likely due to the numerous technical advantages sulfate-based leaching systems offers relative to other lixiviants. Laboratory investigations into atmospheric concentrate leaching processes are explored in Part III of this series.