A Study on Removal of Aqueous Arsenic using the Carbonation Process

Abstract

The carbonation process, one of the calcium carbonate precipitating methods, consists of a reaction of Ca(OH)2, CO2, and water. In this study, laboratorial tests were conducted to remove the arsenic from the abandoned mine drainage and ground water using the carbonation process. As (III) and As (V) were removed up to 26.5% and 90.6%, respectively in the preliminary test and up to 38.7% and 95.1%, respectively in the second test with an increased amount of hydrated lime. Final pH's of reacted solutions were 6.0 to 6.5, which are satisfying with the water standard and Eh's range between -330 mV and +50 mV. Calcite peak was observed in the reaction precipitates of the follow-up test by XRD analysis and also, hexahedral structures of calcite crystals were identified by SEM analysis. As (III) and As (V) were detected in the range of below 0.04% and 0.06 0.07%, respectively by EDS scanning. Consequently, the carbonation process can remove aqueous As (V) efficiently, but As (III) insufficiently.

Effect of Oxidation on Selective Precipitation of Dissolved Fe, Al and Mn in Acid Mine Drainage during Neutralization

“…산성광산배수는 광산주변 수계를 오염시키기 때문에 중화침전법 혹은 자연정화법으로 수처리를 하고 있다. 능동적 정화방법 중 한가지인 중화침전법 이외에도 전기 화학적 농축, 생물학적 정화와 산화, 환원 조절(황산염 환원), 이온교환과 흡착, 응집 또는 여과, 고형화 등의 물 리적, 화학적, 생물학적인 방법을 이용하여 산성광산배 수를 처리하는 방법으로 국내에서도 연구가 계속되고 있 다 (Cheong and Kang, 2004;Kim et al, 2011;Seo et al, 2012;Lee et al, 2013). 중화침전법은 중화제를 이 용하여 pH를 방류수 수질 기준으로 바로 상승시켜 용존 금속을 불용성 슬러지로 침전시키고 상등수는 방류된다.…”