Leaching of Mercury from Contaminated Solid Waste: A Mini-Review

Abstract

Mercury continues to receive attention across a variety of disciplines due to its high mobility and high toxicity to human health and the environment. Sources of mercury-containing solid waste may come from nonferrous metallurgy, mercury mining, electro remediation process, and the chemical manufacturing industry. Significant efforts and resources have been leveraged to develop effective remediation technologies to reduce the hazardous effect of mercury-contaminated waste. Research and development on mercury recovery from mercury-contaminated wastes is reviewed in this article. Though the thermal treatment technologies are used in practice, leaching processes including acid leaching, alkaline leaching and bioleaching, using different lixiviants, have also been developed. It is difficult to conclude which technology offers the best outcomes. However, leaching processes can normally be performed at the site of contamination and can usually remove mercury permanently from wastes in a relatively safe and controlled manner – this is not always true for thermal treatments. Leaching processes can be used independently or in conjunction with other treatment technologies. The selection of leaching lixiviants is highly dependent on the characteristics of the different waste streams. Speciation and coordination of mercury in waste can be critical for application of a recovery technology, especially for leaching processes.