Stability of As(V)-sorbed schwertmannite under porphyry copper mine conditions. (April 2015)

• Record Type: Journal Article
• Authors: HoungAloune, Sengpasith; Hiroyoshi, Naoki; Ito, Mayumi
• Is Part Of: Minerals engineering. Volume 74(2015)
• Page Start: 51
• Page End: 59
• Publication Date: 2015-04
• Subjects: Schwertmannite -- As(V) -- Stability -- Porphyry copper mine -- Tailing -- Spent ore; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2015.01.003
• Languages: English
• ISSNs: 0892-6875

Abstract

Highlights: As(V)-sorbed schwertmannite (Sch-As) stability was studied under Cu mine conditions. Cu 2+ and Fe 2+ had no significant effect on stability of Sch-As. Immobilization of arsenic by schwertmannite was strongly pH-dependent. Sch-As was very stable at pH ranges from 2 to 7 even after ageing for 120-day. Abstract: Arsenic (As), a very poisonous inorganic pollutant is a major toxicant in tailings of porphyry copper deposits. Retention of As by Schwertmannite (a ferric-oxyhydroxysulfate mineral) has attracted much attention in recent years due to its strong binding affinity to toxic As species. The stability of As(V)-sorbed schwertmannite under copper mine waste conditions is not fully understood. The present study investigates the effect of Cu 2+, Fe 2+, pH, and ageing time on the stability of As(V)-sorbed schwertmannite (Sch-As). The results indicate that Cu 2+ has no significant effect on the stability of Sch-As and that the As(V) incorporated in schwertmannite can retard or significantly inhibit Fe 2+ -catalyzed transformation of schwertmannite to goethite under acidic conditions (pH 3–4). The Sch-As aged at different pHs from 3 to 11 at 25 °C exhibits no mineralogical phase changes even after ageing for 120-days; however the concentration of As released from the solid phase appears to be strongly pH-dependent even after ageing for only 24 h. The release of As was negligible at pHs from 2 to 7, and there was considerable release of As at extremely acidic and alkaline conditions. This indicates that the release of As from Sch-As was controlled by environmental factors such as pH, Cu 2+, and Fe 2+ rather than time.