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Inhibition of Acid-Mine-Drainage Formation in Mine Environments and Remediation of Acid Contaminated Sites

矿山环境中酸矿排水的形成抑制及酸污染场地的修复

基本信息

批准号：
09450380
负责人：
TSUNEKAWA Masami
金额：
$ 8.83万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Weathering of pyrite and chalcopyrite plays an important role in formation of acid mine drainage and releases toxic trace elements, such as Ni, Co, Zn and As from the minerals. In mine environments, and especially in aerobic environments, the pyrite and chalcopyrite weathering is accelerated by iron- and sulfur-oxidizing bacteria. This research was conducted on the weathering mechanism, inhibitor to the bacteria and remediation of acid contaminated sites.In acid solutions the preferential dissolution of iron took place resulting in the formation of a surface layer enriched with sulfur. Natural organic acid, such as tannic acids, wood vinegar, fulvic acids, and humic acids, suppressed microbially mediated dissolution of pyrite. It was caused by adsorption of natural organic acids on pyrite, inhibition of cell growth, as well as reduction and complexation of Fe(III) ions.Ferrous ions enhanced copper extraction in sulfuric acid solutions in air at ambient temperatures because they promoted chalcopyrite oxidation with dissolved oxygen. However iron-oxidizing bacteria consumed ferrous ions, suppressing copper extraction. Sodium lauryl sulfate and tannic acid suppressed not only the bacterial ferrous oxidation but also the chalcopyrite oxidation with dissolved oxygen, resulting in a suppression of copper extraction.Dissolution of iron from high sulfur coal refuse by iron-oxidizing bacteria was depressed in the presence of sodium lauryl sulfate, which inhibited cell growth. However, the refuse contained some soluble iron species that could release into drainage. For decreasing iron concentration of drainage addition of lime was effective.

黄铁矿和黄铜矿的风化作用对酸性矿山废水的形成起着重要的作用，并释放出有害的微量元素，如Ni，Co，Zn和As。在矿山环境中，特别是在有氧环境中，黄铁矿和黄铜矿风化被铁和硫氧化细菌加速。本文对酸污染场地的风化机理、抑菌剂及修复进行了研究，结果表明：在酸性溶液中，铁的优先溶解导致表面富硫层的形成。天然有机酸，如单宁酸，木醋，富里酸，腐殖酸，抑制微生物介导的黄铁矿溶解。这是由于天然有机酸对黄铁矿的吸附、抑制细胞生长以及Fe（III）离子的还原和络合作用造成的，亚铁离子促进了黄铜矿与溶解氧的氧化，从而促进了铜在硫酸溶液中的萃取。然而，铁氧化细菌消耗亚铁离子，抑制铜提取。十二烷基硫酸钠和单宁酸不仅抑制细菌亚铁氧化作用，而且抑制溶解氧对黄铜矿的氧化作用，从而抑制铜的提取;十二烷基硫酸钠抑制铁氧化细菌从高硫煤矸石中溶铁，抑制细胞生长。然而，垃圾中含有一些可溶性铁物种，可以释放到排水。掺加石灰对降低排水中铁浓度是有效的。