The effect of jet reactors on the leaching of gold from ores

The extraction of metals from ores by means of appropriate solvents has been practised for many years. A number of methods involve leaching of crushed ores held in tanks or ponds in which the solvent is sprayed over the ore, of which effectiveness is enhanced by mechanical agitation and increased temperature and pressure. In contrast, this investigation uses a high-velocity impinging stream reactor to induce micro-cracking in the ore phase, and consequently enhance leaching kinetics by improved solvent/ore contact. Initial tests show that jet reactor leaching of a free milling ore can increase gold recovery by 10% while decreasing leaching time by up to 90%. Further investigation is required regarding refractory ores, taking into account the complex mineralogy of each ore. The three refractory ores that were tested, all behaved very similarly when subjected to jet reaction. There is no apparent improvement in recovery. However, leaching kinetics are dramatically increased when these ores are subjected to jet reaction prior to agitation.