Recovery of non-ferrous metals from Allarechensk waste dump by low-temperature roasting pathway

Abstract

Processing of Allarechensk technogenic deposit (Murmansk region, Russia) by the low-temperature roasting method in mixture with ammonium sulfate was carried out in a laboratory scale. The ore was grinded to various size classes, mixed with ammonium sulfate and the mixture was roasted in a muffle furnace under a static air atmosphere, varying the roasting temperature from 300 to 500 °C, roasting duration from 60 to 300 minutes. The roasted mixture was leached in heated distilled water with constant stirring for 40 minutes. Using a particle size class of -40 microns, a raw material to reagent ratio of 1:7, after roasting at a temperature of 400 °C at the water leaching stage the metals recovery was: Ni 91.5%, Cu 94.8%. Copper was extracted from the pregnant solution by the method of cementation on iron, and nickel was extracted by adding brucite (Mg(OH)2) to the solution.