HYDROMETALLURGICAL PROCESSING OF OLD FLOTATION TAILINGS
A.G. Bulaev1,*, V.S. Melamud1,**
1
Winogradsky Institute of Microbiology, Research Center of Biotechnology RAS, Russian
Academy of Sciences, Leninsky ave., 33/2, Moscow, Russia, 119071
*bulaev.inmi@yandex.ru,** pivovar@inmi.ru
Sulfide ore processing are characterized by significant losses of metals, for example, with
flotation tailings. Therefore, flotation tailings can present an important source of metals. The
treatment of flotation tailings is technological issue due to low content of valuable metals (e.g.
copper and zinc) and high content of iron. The goal of the present work was to investigate
extraction of base metals and gold from the old flotation tailings contained 17% of iron, 0.26%
of copper, 0.22% of zinc, and 0.7 g/t of gold. Chemical leaching in columns with sulfuric acid
solutions (concentrations from 0.5 to 10%) and bioleaching in air-lift percolators were used for
the extraction of base metals. The concentrations of metals in pregnant solutions of the acid
leaching are presented in Fig. 1. 1% H2SO4 provided high extraction of base metals and best
selectivity. Recovery of copper and zinc reached 35% and 40%. The increasing of
H2SO4concentration did not led to significance increasing of base metals extraction but led to
increasing of iron concentration in the pregnant solutions. The solid residue of leaching with 1%
H2SO4 was used for further experiments. The acid leaching and bioleaching did not resulted in
significant increasing in base metals recovery. Leaching of the residue with 10% H2SO4
provided extraction of 4% and 20%, and bioleaching for 100 days provided extraction of 16%
and 12% of copper and zinc, respectively. The recovery of gold by cyanidation from the flotation
tailings, residue of acid leaching with 1% H2SO4 and residue of two-step acid leaching were 50,
49 and 65%, respectively. The results suggests that acid leaching can be effective approach for
treatment of old flotation tailings.
Figure 1 – Concentrations of the metals in pregnant solutions of the acid leaching with sulfuric
acid solutions.
KEYWORDS
Flotation tailings, acid leaching, bioleaching