TY - JOUR
T1 - The Combined Effects of Galvanic Interaction and Silicate Addition on the Oxidative Dissolution of Pyrite
T2 - Implications for Acid and Metalliferous Drainage Control
AU - Qian, Gujie
AU - Fan, Rong
AU - Short, Michael
AU - Schumann, Russell
AU - Pring, Allan
AU - Gerson, Andrea
PY - 2019/10/15
Y1 - 2019/10/15
N2 - The aim of this study was to determine the combined effect of galvanic interaction and silicate addition on the dissolution of pyrite, the major contributor to acid and metalliferous drainage (AMD). Single (pyrite, sphalerite, and galena)- A nd bi-sulfide (pyrite-sphalerite and pyrite-galena) batch dissolution experiments were carried out with addition of 0.8 mM dissolved silicate for comparison to previously published data. The pyrite dissolution rate was reduced by 98% upon silicate addition at pH 7.4 with little effect at pH 3.0 and 5.0. The effect of galvanic interaction on reducing pyrite dissolution decreased with increasing pH and was greater in the presence of sphalerite than galena. In contrast, the effect of silicate addition increased with increasing pH and was greater in the presence of galena than sphalerite. The greatest combined effect was at pH 7.4, with <0.1% of pyrite leached in both bi-sulfide systems. Silicate addition also significantly reduced the dissolution of sphalerite or galena (by 10-44%, except at pH 3 for the pyrite-sphalerite system). These results suggest that silicate addition, for reducing both pyrite dissolution and metalliferous drainage, may be applicable at a broad pH in mixed sulfide systems.
AB - The aim of this study was to determine the combined effect of galvanic interaction and silicate addition on the dissolution of pyrite, the major contributor to acid and metalliferous drainage (AMD). Single (pyrite, sphalerite, and galena)- A nd bi-sulfide (pyrite-sphalerite and pyrite-galena) batch dissolution experiments were carried out with addition of 0.8 mM dissolved silicate for comparison to previously published data. The pyrite dissolution rate was reduced by 98% upon silicate addition at pH 7.4 with little effect at pH 3.0 and 5.0. The effect of galvanic interaction on reducing pyrite dissolution decreased with increasing pH and was greater in the presence of sphalerite than galena. In contrast, the effect of silicate addition increased with increasing pH and was greater in the presence of galena than sphalerite. The greatest combined effect was at pH 7.4, with <0.1% of pyrite leached in both bi-sulfide systems. Silicate addition also significantly reduced the dissolution of sphalerite or galena (by 10-44%, except at pH 3 for the pyrite-sphalerite system). These results suggest that silicate addition, for reducing both pyrite dissolution and metalliferous drainage, may be applicable at a broad pH in mixed sulfide systems.
KW - Galvanic interaction
KW - Silicate dissolution
KW - Pyrite
KW - Acid and Metalliferous Drainage
UR - http://purl.org/au-research/grants/arc/LP140100399
UR - http://purl.org/au-research/grants/arc/LP130100568
UR - http://www.scopus.com/inward/record.url?scp=85073014094&partnerID=8YFLogxK
U2 - 10.1021/acs.est.9b03965
DO - 10.1021/acs.est.9b03965
M3 - Article
VL - 53
SP - 11922
EP - 11931
JO - Environmental Science and Technology
JF - Environmental Science and Technology
SN - 0013-936X
IS - 20
ER -