Inhibition of pyrite oxidation by surface coating: a long-term field study.
Pyrite and other iron sulfides are readily oxidized by dissolved oxygen in aqueous phase, producing acidity and Fe(2+), which causes significant environmental problems. Applications of surface coating agents (Na2SiO3 and KH2PO4) were conducted at Boeun (Chungbuk, South Korea) outcrop site, and their efficiencies to inhibit the oxidation of sulfide minerals were monitored for a long-term period (449 days). The rock sample showed positive Net Acid Production Potential (NAPP = 20.23) and low Net Acid Generation pH (NAGpH = 2.42) values, suggesting that the rock sample was categorized in the potential acid-forming group. For the monitored time period (449 days), field study results showed that the application of Na2SiO3 effectively inhibited the pyrite oxidation as compared to KH2PO4. Na2SiO3 as a surface coating agent maintained pH 5-6 and reduced oxidation of pyrite surface up to 99.95 and 97.70 % indicated by Fe(2+) and SO4 (2-) release, respectively. The scanning electron microscope and energy-dispersive X-ray spectrometer analysis indicated that the morphology of rock surface was completely changed attributable to formation of iron silicate coating. The experimental results suggested that the treatment with Na2SiO3 was highly effective and it might be applicable on field for inhibition of iron sulfide oxidation.
Department of Natural Resources and Environmental Engineering, Hanyang University, 222, Wangsimni-ro, Seoul, 04763, South Korea.
Chan-Ung
CU
Kang
Department of Natural Resources and Environmental Engineering, Hanyang University, 222, Wangsimni-ro, Seoul, 04763, South Korea.
Byong-Hun
BH
Jeon
Department of Natural Resources and Environmental Engineering, Hanyang University, 222, Wangsimni-ro, Seoul, 04763, South Korea.
Seong-Sook
SS
Park
Department of Natural Resources and Environmental Engineering, Hanyang University, 222, Wangsimni-ro, Seoul, 04763, South Korea.
Jin-Soo
JS
Kang
Department of Natural Resources and Environmental Engineering, Hanyang University, 222, Wangsimni-ro, Seoul, 04763, South Korea.
Kang-Ho
KH
Kim
Mine Reclamation Corporation, 2, Segye-ro, Wonju, 16464, South Korea.
Dong-Kwan
DK
Kim
Mine Reclamation Corporation, 2, Segye-ro, Wonju, 16464, South Korea.
Ui-Kyu
UK
Choi
Department of Natural Resources and Environmental Engineering, Hanyang University, 222, Wangsimni-ro, Seoul, 04763, South Korea. nnsjkim@hanyang.ac.kr.
Sun-Joon
SJ
Kim
D052918:Environmental Restoration and Remediation / Q000379:methods*; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D010710:Phosphates / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D056910:Republic of Korea; D017640:Silicates / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013440:Sulfides / Q000737:chemistry*
D010710:Phosphates; D017680:Potassium Compounds; D017640:Silicates; D013440:Sulfides; C025349:sodium metasilicate; C011342:pyrite; C013216:potassium phosphate; D007501:Iron
Acid mine drainage; Pyrite oxidation; Sulfide mineral; Surface coating