Silver, gold and lead recovery from bioleaching residues using the PLINT process

Single, or complex copper, nickel and zinc ores and concentrates, frequently contain important amounts of silver and gold, together with other minor metals. Cu, Ni and Zn are easily and efficiently dissolved in mesophilic or thermophilic bioleaching processes, while Au, Ag and Pb remain in the residue. Having a mainly jarositic matrix, these residues are usually refractory to conventional cyanidation or concentration processes. The PLINT technology developed by Técnicas Reunidas is a simple, clean and efficient procedure for gold and silver recovery from bioleaching residues (especially of a jarositic nature) unable to be treated by conventional processes. This process is very flexible and adaptable to suit every specific application requirement. Results of a preliminary feasibility study on the application of the PLINT technology on a copper bioleaching residue are presented in this paper. Very appealing economic figures are shown together with main technical performance parameters and a summarised process description.