Mining in focus
Limestone is mined from a number
of quarries around the country.
The major copper-producing countries, such as
Zambia and Chile, have domestic supply of lime
and can produce limited amounts of quicklime.
Limestone grab sampling.
smelters. Lime products are also used
to neutralise the dumps in an effort to
remediate acid mine drainage (AMD).
In copper mining, about 80% of
the produced quicklime is used in
flotation processes. Depending on the
ore to be treated, the quicklime unit
consumption value ranges from 1.5 to
1.7kg/ton of processed copper ore.
The major copper-producing
countries, such Zambia and Chile,
have domestic supply of lime and can
produce limited amounts of quicklime.
The domestic production, however, does
not meet the annual demand and these
countries are dependent on import. In
the case of Zambia, quicklime is also
imported from South Africa, and Chile
imports from Argentina.
“The quicklime market was
significantly affected by the worldwide
economic downturn and on average, the
demand decreased by about six per cent
per year since 2012,” says Scott. The
situation is estimated to turn around
with the current commodity price
uptick and market recovery anticipated
in 2019.
Quicklime prices are not readily
available, but the average selling price
in 2015 was USD156.70/ton. In the
period 2005–2015, the average year to
year increase in quicklime prices were
9,9%, with the trend set to continue
for the near future. This scenario is
dependent on the assumption that
quicklime import volumes do not
increase substantially, and no new
quicklime production projects come
into full production in the next two to
three years. The consumption of lime
is most likely to remain stable as a pH
modifier and acid neutraliser in the
production of copper cathodes. In the
absence of any cheaper replacement
product and in the increase of demand,
particularly from the copper-producing
industry, demand is set to increase for
the near future.
The downside potential is that the
production of quicklime is highly
fossil-fuel intensive and it produces
large amounts of CO₂, subsequently
being the focus of environmental
concerns. Although smelting remains
the preferred method of processing,
hydrometallurgical processes are
being refined and may take a larger
portion of the market in future.
Research is being conducted to
reduce the consumption of lime in
flotation of copper- and nickel-
bearing minerals. b
JUNE 2018 MINING MIRROR
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