|About this Abstract
||Part C-1: Hydrometallurgy 2018
||Arsenic Immobilization in Nanostructured (Al) Fe-(hydr)oxides
||Virginia S.T. Ciminelli, Erico T. F. Freitas, D. Delbem, Massimo Gasparon
|On-Site Speaker (Planned)
||Virginia S.T. Ciminelli
A mechanism responsible for long-term arsenic immobilization in nanostructured Fe-(hydr)oxides, and based on a non-classical aggregation crystal growth is discussed. Experimental evidence is provided by the analyses of tailings from pressure oxidation-gold cyanidation, soil samples from a gold mining region, and synthesized samples aged for up 120 days at ambient temperature. The common pattern is the predominance of oriented aggregates of nanostructured (Al)Fe-(hydr)oxides where arsenic is mainly found in the interstices of nanoparticles-building-units. Arsenic concentrations as high as 6.9±0.3 wt% As and 1.6±0.5 wt% As were determined in grains of ferrihydrite and hematite, respectively. The role of aluminum is discussed. The combination of statistically sound scanning electron microscopy with automated image analysis and high-resolution transmission electron microscopy is shown to bring a new understanding of the association of arsenic with iron (hydr)oxides, and proved effective to substantiate data on tailings stability and potential risks to human health.
||Planned: At-meeting proceedings