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

Advances in depressants used for pyrite flotation separation from coal/minerals

“…In addition, Cu activation of sphalerite occurs in two steps: (1) substitution of Zn 2+ with Cu 2+ and (2) oxidation of S 2− to S − by the reduction of Cu 2+ to Cu + , followed by a CuS-type layer formation on the mineral surface. The zeta potential of copper-activated sphalerite showed almost similar zeta potential as that of CuS (Fletcher et al 2020). Thus, the floatability of sphalerite is affected by the concentration of copper.…”

“…Cu 2+ adsorbed on the pyrite surface undergoes an immediate redox reaction with S 2− to generate Cu + and S − ; at the same time, Fe 2+ is oxidized to Fe 3+ by S − , which then reduces to S 2− (Fig. 1) (Fletcher et al 2020). After being activated by Cu 2+ , the surface potential of pyrite changes from positive to negative; this potential was observed to be close to that of CuFeS 2 .…”

“…Chalcopyrite (CuFeS 2 ) layers might have formed on the pyrite surface (Ejtemaei and Nguyen 2017). CuFeS 2 easily interacts with xanthate or oil collectors, improving the floatability of pyrite under alkaline conditions (Fletcher et al 2020). In addition, Cu activation of sphalerite occurs in two steps: (1) substitution of Zn 2+ with Cu 2+ and (2) oxidation of S 2− to S − by the reduction of Cu 2+ to Cu + , followed by a CuS-type layer formation on the mineral surface.…”

“…The main disadvantages of inorganic reagents are their toxicity, corrosiveness, and nondegradability, which are harmful to the environment. As such, nontoxic, renewable, and readily biodegradable natural polysaccharides such as starch, dextrin, guar gum and carboxymethyl cellulose (CMC) were evaluated as pyrite depressants (Bulut et al 2011;Fletcher et al 2020). The main factors that influence the properties of organic depressants are molecular structure, type of functional group, polymer molecular conformation, and pulp pH.…”

Investigations on a novel collector for anionic reverse flotation separation of quartz from iron ores

“…The acidity of fatty acid was usually influenced by the saponification process (Poulenat et al, 2003). Moreover, the oxidation process could introduce some functional groups, such as carbonyl (-C=O), carboxyl (-COOH) and peroxide hydroxyl (−OOH), which alter the polarity functionality along the carbon chains of fatty acid (Fletcher et al, 2020). In this article, the increase of acidity was largely dependent on the introduction of peroxide hydroxyl (−OOH).…”