Adding Value to Mine Waste through Recovery Au, Sb, and As: The Case of Auriferous Tailings in the Iron Quadrangle, Brazil

Abstract

From the colonial era to modern times, gold mining has played a crucial role in shaping Brazil’s economy, culture, and landscape, particularly in the Iron Quadrangle region. Therefore, resulting waste has accumulated in tailings structures, either from deactivated circuits or plants still in production. The present study reveals the potential assessed based on a set of metallurgical tests, assuming specific scenarios depending on the occurrence modes of interesting economic elements. For Au, calcination, leaching, and flotation are promising techniques to recover this element. Tests indicated that toxic elements such as Sb and As could be effectively reused in the form of glass. The generation of other products from dry cleaning techniques was not effective but promising since there was an enrichment of elements with Au, Fe, Al, and K in specific fractions.

The Development of Innovated Complex Process for Treatment of Old Flotation Tailings of Copper-Zinc Sulfide Ore

“…These metals can be released into the liquid phase during the storage, which is harmful or potentially harmful to the environment, due to the migration of various released ions possessing long-term harmful effects in areas of tailing disposal. These harmful effects were noted in different regions with various climate conditions [9,[13][14][15][16][17][18][19][20].…”

“…The reserves of metals contained in flotation tailing in some sites may be estimated as significant due to the large volumes of wastes accumulated from decades of exploitation of some mineral deposits [15,17,21]. Therefore, investigations have been carried out in recent decades to estimate the possibility of metal extraction from old sulfide-containing tailings using different approaches, which include hydrometallurgical techniques (acid leaching (with sulfuric, organic, hydrochloric leaching), leaching with sodium chloride, cupric chloride, ammonium salts, different oxidants, cyanidation, column and stirred tank reactor bioleaching [2,8,18,[21][22][23][24][25][26][27][28][29], roasting [30] and flotation [3], as well as treatment of AMD formed in tailing disposal areas as source of metals [16]. The results of these studies suggest that valuable metals can be successfully extracted from these wastes and high levels of extraction can be reached, while the specific chemical and mineral composition and high iron content (in the form of pyrite and oxide minerals) result in difficulties in base metal extraction.…”