Lyn Jones, Senior Consultant of M.Plan International, presents at CIM’s Academy for Online Learning on October 14th, 2020: “Cobalt Recovery from a Pyrite Concentrate”

Abstract: Capstone Mining’s Santo Domingo Project in Chile’s Region III is expected to produce 3.8Mt of copper and 75Mt of magnetite concentrate over the projected 18-year mine life. The resource also averages 241 ppm cobalt. A preliminary economic study on the cobalt opportunity was completed February 2020.

The contained cobalt is found within the matrix of the pyrite and can be concentrated into a by-product as part of the copper recovery process, with the potential to generate approximately 2700 tpd of pyrite concentrate grading an estimated 0.60% cobalt and 0.40% copper. Attempts to further upgrade the cobalt flotation concentrate were unsuccessful, but preliminary testwork has indicated that high cobalt extractions are possible, provided that the sulfide mineral is first oxidized.

A flowsheet has been developed that includes dead roasting of the concentrate at 660 – 680 °C, followed by atmospheric leaching of the residue under mildly acidic conditions to extract cobalt and copper. The leach solution undergoes four stages of purification including copper recovery by NaHS precipitation. The purified solution feeds a cobalt solvent extraction circuit, which in turn provides a concentrated feed to a cobalt sulfate crystallization step.

Lyn’s paper details the development of the selection criteria and process design to generate a viable by-product stream targeted at the emerging battery metals market.

To access Lyn’s presentation via the CIM Academy, please click here to register.