In order to remove the iron oxides and most of the silicon oxides present, the ore is first treated with sodium hydroxide. The digestion process takes advantage of the solubility of amphoteric aluminum oxides to form a solution of aluminate ions, whilst the basic iron oxides which form do not dissolve and are separated by filtration.
Australia's iron ore reserves and resources are in both hematite and magnetite ores. Because of the high average grades (% Fe) of hematite ores when compared to the average grades for magnetite ores, it is necessary to report national resources in terms of contained iron.
Process. The Company completed Laboratory scale test work between 2011 and 2013 which included batch smelting test, slag testing, agglomeration behaviour of the ore, Liquidus measurement of FeNi slag under conditions corresponding to electric furnace smelting, performance of the nickel laterite in rotary kiln processing and evaluation of briquetting behavior.