SCORODITE IN THE CESL PROCESS FOR COPPER-ARSENIC CONCENTRATES
*K. Mayhew1 and H. Salomon-De-Friedberg1, A. Lossin2
1
Teck Resources Limited
12380 Horseshoe Way
Richmond, B.C., Canada
V7A 4Z1
(*Corresponding author: keith.mayhew@teck.com)
2
Aurubis AG
Hovestraße 50
Hamburg 20539, Germany
ABSTRACT
The proportion of arsenic-bearing copper concentrates that supply the copper industry is on the
increase. The current strategy of miners and smelters to blend feeds to reduce average arsenic levels is
rapidly becoming unsustainable as more concentrates with even higher arsenic levels enter the
marketplace. In addition, the capability of smelters to manage increasing arsenic levels to more stringent
and restrictive environmental standards is limited by available process technologies.
CESL Cu-As Technology is a viable technical and economic alternative to traditional smelting. It offers
the advantage of simultaneous leaching and precipitation of the arsenic in a single processing step while
achieving high copper extractions. The process has been piloted in five separate, fully-integrated pilot
campaigns for feeds ranging from ~1% to 12% arsenic in concentration. This paper will focus on the
behaviour of arsenic in CESL’s leaching/precipitation step and operational factors that influence it, and on
the chemical and physical characteristics of the subsequent iron-arsenic residue that represents today’s best
available technology from a long-term sustainable (capital/operating costs, metal recovery, safety,
environmental) perspective.
The examples provided will demonstrate copper extractions approaching 99% and arsenic deportment to
residue of 99%. Instantaneous settling rates of the residue were measured at 15+ m/hr. Data from
subsequent short and long-term stability testing of the residue confidently support the view that the
scorodite-bearing residues from the process will be stable and provide an acceptable arsenic management
practice. The technology offers increased revenue and environmental certainty for miners, smelters &
refiners to support the development of metallurgically challenged copper-arsenic deposits.
KEYWORDS
Arsenic, Scorodite, Solid/liquid, Copper concentrate, CESL