Fp. Gudyanga et al., REDUCTIVE-OXIDATIVE PRETREATMENT OF A STIBNITE FLOTATION CONCENTRATE - THERMODYNAMIC AND KINETIC CONSIDERATIONS, Minerals engineering, 11(6), 1998, pp. 563-580
Citations number
16
Categorie Soggetti
Mining & Mineral Processing",Mineralogy,"Engineering, Chemical
The thermodynamics and kinetics of reductively decomposing stibnite (S
b2S3), a refractory sulphide, using an acidified solution of chromium(
II) ions in a chloride medium (for Au recovery) have been considered.
Results show that well over 80% reduction of stibnite to antimony (Sb)
and hydrogen sulphide (H2S) is achieved, the extent of reduction bein
g pH and reductant concentration dependent. The contrasting temperatur
e sensitivity above and below 90 degrees C (363K) suggests that two ra
te controlling modes are operative: diffusion in the range 60-90 degre
es C(333-363K) and chemical reaction above 90 degrees C. Although up t
o 80% reduction of the sulphide host mineral (Sb2S3) occurred, very li
ttle gold (<16%) was liberated. A sequential reductive-oxidative pretr
eatment of the stibnite ore achieved 90% gold liberation. This strongl
y suggests that in the stibnitic ores, the sulphide species are not wh
olly responsible for the reported refractoriness. Gold may be in submi
croscopic form as finely disseminated fine particles or in solid solut
ion as aurostibnite (Au3S) which requires further oxidative treatment
after the sulphide decomposition. (C) 1998 Published by Elsevier Scien
ce Ltd. All rights reserved.