Abstract

Pyrogallol, an eco-friendly derivative of tannic, was a potential substitute of toxic depressant used in

bismuth-molybdenum (BieMo) sulfide oreflotation. However, unclear depression mechanisms of pyrogallol on bismuth sulfides hindered its further application in the industry. In this work, the effect of

pyrogallol on theflotation performance of bismuthinite was evaluated usingflotation tests, and associated interaction mechanisms were investigated by using Fourier transform infrared spectroscopy

(FTIR), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. Microflotation tests showed that pyrogallol exhibited excellent depressing performance to bismuthinite in the

whole pH range tested (2e12). In the presence of 300 g/t pyrogallol, over 95% of bismuthinite was

effectively depressed in the realflotation process at pH around 9. FTIR and XPS results demonstrated that

pyrogallol was chemisorbed on bismuthinite through the interactions among Bi atoms exposed on the

bismuthinite surface and O
H groups in pyrogallol. The adsorption mechanism was further ascertained

by DFT calculations, which revealed that the BieOeC single bond and thefive-membered ring complex

models were involved in the chemisorption of pyrogallol on bismuthinite surface. The work presented

here not only provides new insights into the inhibition mechanisms of pyrogallol on bismuthinite but

also provides theoretical support for the industrial application of pyrogallol

Keywords:

Bismuthinite

Pyrogallol

Flotation

Depression mechanism

Chemisorption