Project title Life cycle assessment of the production of xanthate salts and of their application for ARD mitigation Supervisors: Dr JL Broadhurst, Prof H von Blottnitz and Dr P Dicks
Xanthate salts are commonly used as collectors in the mineral processing of sulphide ores. In more recent studies conducted at the University of Cape Town and in Canada, xanthate has been used in the desulphurization flotation of copper sulphide tailings and coal waste to mitigate acid rock drainage (ARD) risks. Xanthate salts are produced by Senmin® International (Pty, Ltd) through the conversion of carbon disulphide at their facility in Sasolburg, South Africa. In 2010, Senmin commissioned a new state-of-the-art plant for the production of carbon disulphide, which has many advantages over the previous process.
No attempt has, however, been made to quantify the environmental benefits of the current (new) process for carbon disulphide production relative to the previous one and, ultimately, of xanthate production and use. The life cycle assessment (LCA) approach could prove to be a valuable tool to study the environmental aspects and potential impacts throughout a product’s (process’ or service’s) life cycle, from raw material extraction through production, use and disposal.
In line with Senmin®’s commitment to optimising their environmental performance, this study aims to use life cycle assessment tools to identify and compare the environmental impacts of the current and previous carbon disulphide production process, as well as the subsequent effects of such on xanthate production and its down-stream application, insofar as it pertains to the desulphurisation of copper sulphide tailings. This information will, in turn, assist in the identification of opportunities for improving environmental performance across the xanthate production and ARD mitigation process system, and thus play a key role in guiding further developmental studies in this area.