A comparison of native starch, oxidized starch and CMC as copper-activated pyrite depressants

摘要

The separation of pyritic gangue from chalcopyrite during copper flotation can be made more efficient by using depressants such as starch and carboxymethyl cellulose (CMC). The non-toxicity of these naturally sourced biopolymers makes them attractive reagents for improving the sustainability of mineral processing operations. Generally, starch is less expensive, but CMC is often more effective. The choice of what to use in a particular flotation system depends on the operational and economic benefits each can offer. In this study, the performance of a CMC, native wheat starch and an oxidized version of the wheat starch are compared in lab-scale flotation of copper-activated pyrite. These results are explained in terms of mineral surface/polymer interactions using adsorption isotherms and polymer properties such as kinematic viscosity, molecular weight distribution, and substituted functional groups.