New insights about the bacterial oxidation of arsenopyrite: A mineralogical scope

Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic

“…Raman backscattering showed a signal/noise ratio N100 for Si analyses. The vibrational range was from 100 to 750 cm − 1 as S n 2 − /S 0 and main arsenic-bearing phases show their main active modes within this interval (Mycroft et al, 1990;Márquez et al, 2012). At least 10 Raman spectra were collected for each arsenopyrite surface.…”

“…1a shows the Raman spectrum for pristine MAE, displaying typical broad peaks at~199,~252 and~264 cm −1(McGuire et al, 2001;Márquez et al, 2012). A summary of characteristic Raman transitions are described in…”

Effect of Pretreatment of Sulfide Refractory Concentrate with Sodium Hypochlorite, Followed by Extraction of Gold by Pressure Cyanidation, on Gold Removal

“…However, the chemistry of arsenopyrite in relation to its dissolution, flotation, and electrochemistry has received little attention [6]. Therefore, in alkaline oxidizing conditions, arsenopyrite can be oxidized to ferrous hydroxide, arsenate ( 4  or 4 depending on pH), and to sulfate with iron hydroxides and arsenites as intermediates. The overall reaction for the alkaline oxidation of arsenopyrite might be described by the following equation:…”

“…A clear boundary between refractory and non-refractory ore in terms of gold recovery is not well defined, but several authors have pointed out that less than 60% gold recovery by direct cyanide leaching, after fine grinding of mineral indicates a refractory mineral [1]. The refractory ore must be destroyed or attacked by chemical means with the use of oxidative processes, such as oxidation by roasting [2], pressure oxidation [3], bio-oxidation [4], and ultrafine grinding [5]. Then, a suitable pretreatment process is often required to overcome the refractoriness and render the gold and silver accessible to the lixiviante action of cyanide and oxygen [1].…”

The Catalytic Role of Acidithiobacillus ferrooxidans for Metals Extraction from Mining - Metallurgical Resource

“…biohydrometallurgy. [7][8][9][10][11][12][13] The advantages of bioleaching of ores and concentrates are compared to conventional metodes, such as pyrometallurgy,reflected in: the potential for processing of low-grade deposits and deposits with significant amounts of arsenic, [14][15][16][17][18] reprocessing waste, lower energy consumption, as well as environmental benefits (e.g., no toxic gases). 19 In the industrial leaching processes, microorganisms that are found in nature can be used.…”