Long-Term Acid-Generating and Metal Leaching Potential of a Sub-Arctic Oil Shale
| Autor: | Damian B. Gore, Ian Snape, Ashley T. Townsend, Brendan Pitt, Kathryn A. Mumford |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
oxidation reduction potential
lcsh:Mineralogy lcsh:QE351-399.2 metal concentration Environmental remediation pH Fluorescence spectrometry Mineralogy Geology total reflection X-ray fluorescence spectrometry (TRXRF) Unconventional oil acid rock drainage Geotechnical Engineering and Engineering Geology Sub arctic Reduction potential Environmental chemistry Leachate Leaching (metallurgy) Oil shale |
| Zdroj: | Minerals Volume 4 Issue 2 Pages 293-312 Minerals, Vol 4, Iss 2, Pp 293-312 (2014) |
| ISSN: | 2075-163X |
| DOI: | 10.3390/min4020293 |
| Popis: | Shales are increasingly being exploited for oil and unconventional gas. Exploitation of sub-arctic oil shales requires the creation of gravel pads to elevate workings above the heaving effects of ground ice. These gravel pads can potentially generate acidic leachate, which can enhance the mobility of metals from the shale. To examine this potential, pyrite-bearing shale originating from sub-Arctic gravel pad sites were subjected to leaching tests for 600 days at initial pH values ranging from 2 to 5, to simulate potential real world conditions. At set times over the 600 day experiment, pH, oxidation reduction potential (ORP), dissolved oxygen and temperature were recorded and small liquid samples withdrawn and analysed for elemental concentrations using total reflection X-ray fluorescence spectrometry (TRXRF). Six of eight shale samples were found to be acid generating, with pH declining and ORP becoming increasingly positive after 100 days. Two of the eight shale samples produced increasingly alkaline leachate conditions with relatively low ORP after 100 days, indicating an inbuilt buffering capacity. By 600 days the buffering capacity of all samples had been consumed and all leachate samples were acidic. TRXRF analyses demonstrated significant potential for the leaching of S, Fe, Ni, Cu, Zn and Mn with greatest concentrations found in reaction vessels with most acidic pH and highest ORP. |
| Databáze: | OpenAIRE |
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