MINING CHEMICALS
unlike the conventional process which produces
only allows to obtain Li 2 CO 3 .
CYANEX ® 936P is an organo-phosphorus
reagent that acts through a chelating mechanism
by exchanging metal ions (Li + ) for protons (H + ).
Chinese mining chemicals trading group
Kemcore recently received the first batch of
sulphuric acid tankers as it steps up efforts to
increase its rail capacity to supply sulphuric acid
to its mining clients in Zambia and the DRC
The reagent allows a selective extraction from
brines rich in Cl, SO 4 , Na, B and K, where lithium
is one of the least abundant elements.
“It is important to bear in mind that the
reagent is not selective with respect to divalent
elements such as Mg 2+ and Ca 2+ , which must be
removed from the brine prior to the SX process.
There are different technologies available to
remove divalent ions: ion exchange, membranes,
precipitation, or even SX (using DEHPA or
CYANEX ® 272 reagents is technically feasible);
the various options should be evaluated
according to the characteristics of the brine to be
recovery rate can be achieved
treated.”
The reagent requires neutralisation of the
protons generated as part of the extraction
equation. For this, base is added directly to the n It does not require large areas for evaporation
n The processing time is reduced to hours, not
months (positively affecting time-to-market
feed brine. The base achieves the objective of
neutralizing the protons generated, and also
precipitates the traces of Mg and Ca that could
remain in the solution. The stoichiometric ratio
requires a base dosage of 1 mole of OH per mole n The evaporation of millions of cubic meters of
water is no longer needed to concentrate the
brine. It is possible to return the raffinate of
of Li present in the brine.
The CYANEX ® 936P reagent has a high lithium
extraction capacity, reaching a recovery close to
100% from an average brine. The high loading
capacity, along with the fast extraction and
retraction kinetics make it possible to obtain
high purity lithium in a simple SX circuit with a
limited number of theoretical stages.
The reagent was developed in collaboration
with the engineering firm Tenova Advanced
Technologies (TAT). The TAT process provides the
conditions that allow the optimum operation of
the CYANEX ® 936P reagent, ie the neutralisation
and removal of the divalent ions from the feed
brine. The TAT process consists of two main
steps, the LIP™ step for the removal of the
divalent ions and the LiSX™ step which is the
and working capital)
the SX plant to the salar, after treatment to
eliminate the possible entrainments of the
organic phase
n CYANEX ® 936P is flexible and compatible with
different SX technologies: pulsed columns,
mixer-settlers, etc.
“CYANEX ® 936P is an innovative formulation
that can radically change lithium production
technology. It can also be used within the
traditional process, optimising the costs and
performance of the operation.”
Copperbelt logistics
One aspect of the mining chemicals industry that
is often overlooked or taken for granted is bulk
transportation. Chinese mining chemicals trading
group Kemcore, recently received the first batch
of sulphuric acid tankers as it steps up efforts to
lithium solvent extraction itself. Those are
followed by an optional third step called LiEL™,
which is an electrolysis process to produce LiOH increase its rail capacity, to supply sulphuric acid
to its mining clients in Zambia and the DRC.
Kemcore, a Hong Kong-based company, with
offices in South Africa and Zambia in December
of high purity.
It is also possible to apply the lithium SX as
part of the conventional production process in 2018 announced that its newly leased sulphuric
acid rail tank wagons had passed the inspection
at the Germiston wagon depot of Transnet
order to optimise the Li 2 CO 3 precipitation Engineering. The newly acquired sulphuric acid
rail tank wagons will join Kemcore's existing 90
acid wagons, which already include 30
TFR XPJ tanker wagons and 60 ISO tank wagons.
“The wagons were all converted by the same
production line, in the same batch and with the
process. This allows the recovery of the lithium
remaining in the carbonation effluents (known as
“mother liquor”), thus generating significant
savings in reagents and energy. Solvay says that
solvent extraction of lithium has clear
advantages over the conventional process:
n It is independent of climate and geography
n In the case of the TAT process, the overall
recovery of lithium is between 85 and 90%,
and considering only the SX stage, a 99%
48 International Mining | MAY 2019
same material and quality standards, from XPJ-10
fuel tankers to sulphuric acid tankers designated
RLSLJ-1. As such, they are all of the same
specification and quality, and in similar
condition” read the inspection report.
The conversion scope consisted of installation
of a ‘slosh plate’ to reduce longitudinal
movement of the liquid load inside the tank,
installation of new T long neck bottom discharge
valves, and installation of an air brake system
(the wagons are now equipped with dual vacuum
and air brakes). The work also included
refurbishment of running gear components,
namely Saskop couplers and draw gear, brake
gear components and Spoorbarber bogies.
“Kemcore's ability and capacity to rail sulphuric
acid from South Africa is a first for the region and
positions the company as one of the only
companies to do so in the Copperbelt region.
Kemcore is now able to rail 8,000 tonnes per
month of sulphuric acid to off-take partners in
the region,” Kemcore said in a statement.
Sulphuric acid, used in the leaching of copper
has been in short supply since 2017. The region
is heavily dependent on supply from Zambian-
based copper smelters and sulphur burning. The
2019 outlook for supply was looking very tight as
it was becoming expensive for local smelters to
acquire concentrates. This was also being
exacerbated by the introduction of a sales tax by
the Zambia government. Moreover, there were
more than 100,000 t per annum of demand from
new operations expected to commence in 2019.
Kemcore stated: “The price of imported
sulphuric acid from South Africa via road truck
tankers is prohibitively very expensive at above
$600/t. It may become uneconomical as the
price of copper and cobalt go down. Cobalt prices
have dropped more than 25% since a peak in
April [2018] amid growing concerns that too
much supply has been brought online in
response to surging prices. Last week Glencore
warned that some buyers in China reneged on
contracts after seeing prices plunge, forcing the
company to renegotiate the commercial terms of
the deals. Miners will be forced to seek cheaper
alternative sources of acid. The railing of acid
brings the cost down by at least 10% which can
lead to millions of dollars in savings.” IM