Zirconia content enrichment of Indonesian zircon sand by using alkali fusion followed by water leaching and sulfuric acid leaching

Abstract

Naturally available Zircon sand from placer deposit in Borneo Island, Indonesia was processed to enrich the Zirconia content up to 65%. The pre-magnetic separated zircon sand sample is fused with NaOH followed by water and H2SO4 leaching at various concentration, time, and temperature combinations. XRD characterization of initial zircon sand reveals the composition of 47.0% ZrSiO4, 32.0% Magnetite, 10.8% rutile and 10.3 % m-ZrO2. After alkali fusion, water leaching and H2SO4 leaching processes the composition of the processed zircon sand improved to 77.8% ZrSiO4, 12.8% ZrO2, 2.3% ZrO(SO4) and 7.0% rutile. While the free zirconia content improves slightly from 10.3% to 12.8%, the total zirconia content can be improved from 41.9% in the initial zircon sand sample, to economically viable total zirconia content of 66.5% in the final product. In addition the facile processing also eliminates or reduces unwanted impurities phases such as magnetite, rutile, and amorphous SiO2 from the zircon sand sample.