HIGH-PRESSURE LEACHING
Some leaching operations require elevated temperatures and pressures to achieve the desired extraction. Examples of this include pressure oxidation (POX) of sulfide ores and concentrates, high-pressure acid leaching (HPAL) of nickel laterites, and wet-air oxidation of organics. Both batch and continuous reactors, constructed from stainless steel or titanium, are available at Hazen for developing high-temperature processes.
Hazen's engineers have assisted clients in developing POX processes for refractory gold ores, metals recovery from catalysts, and sulfide concentrates of copper, nickel, zinc, and molybdenum. Experience enables Hazen to successfully scale up batch experiments to pilot operations. Several commercial plants throughout the world have been designed, built, and successfully operated based on pilot plant data generated at Hazen.
Processes utilizing HPAL of nickel laterites using sulfuric acid have been piloted at Hazen. These processes involve temperatures up to 250°C at low pH, with the goal of minimizing acid use while maximizing nickel and cobalt extractions.