Purification of Rutile in Sri Lankan beach sand for the extraction of TIO2 by reducing iron content

Abstract

The Pulmuddai region in Sri Lanka is characterized by key constituents: 55-60% ilmenite, 6-8% rutile, and 5-6% iron. Iron's presence emerges as a critical impurity necessitating pre-extraction removal for titanium dioxide extraction from rutile. Attaining a TiO2 purity exceeding 99% within rutile is attainable through targeted iron elimination and meticulous optimization of the purification process. The methodological approach commences with the initial screening and separation of beach sand, utilizing the Humphrey spiral technique to selectively isolate high-density minerals enriched with rutile and ilmenite. Subsequent separation of rutile from ilmenite employs a magnetic separator. The conclusive step involves the strategic removal of iron from rutile via leaching with hydrochloric acid (HCl). Optimization of leaching parameters, including the solid-to-liquid ratio (S/L ratio), HCl concentration, and reaction time, maximizes iron removal from rutile. A comprehensive analysis of samples before and after leaching employs a UV-visible spectrophotometer and scanning electron microscopy utilizing Energy Dispersive X-Ray Spectroscopy on the samples. Results indicate 83.3% reduction in iron content within rutile from the initial raw mineral, achieved under optimized conditions of 1:3 S/L ratio, 80°C, 4-hour reaction time, and 4M HCl concentration.