Review of Chromite Ore Processing Residue (COPR): Past Practices, Environmental Impact and Potential Remediation Methods

Chromite ore processing residue (COPR) is a waste byproduct of chromate production that contains high levels of hexavalent chromium (Cr[VI]). Although the high temperature chromite process was banned in several countries, its legacy still exists at numerous contaminated sites. For instance, New Jersey alone has over 2 million tons of waste COPR. Legacy sites are confounded by the fact that a few countries still produce COPR during chromate extraction that leads to new contamination. This paper reviews the historical production and disposal practices of COPR and provides a concise overview of the different methods for addressing Cr(VI) contamination at old and new COPR sites.