MINING CHEMICALS
like lithium for the battery industry. A recent
client was a spodumene mineral processor,
which opened a mine with intentions of
producing a battery-grade spodumene product.
Their deposit presents unique metallurgical
challenges related to mica- and iron-containing
silicate minerals. The mineralogy of the deposit
is 10-20% spodumene with a high percentage of
quartz and iron silicates, mica, amphibole and
more. In order to produce a battery-grade
product, the spodumene concentrate had to be
upgraded from 0.8-1.2% Li 2 O to >6.0% Li 2 O. The
client’s processing facility was having difficulties
achieving concentrate levels above 4.5% Li 2 O, as
well as making the recovery and production
targets projected in the mine prefeasibility study.
As the plant started up, several processing
challenges reduced recovery versus targets and
hindered processing steps:
n The operation had difficulty meeting
production goals
n The mine started up on a commodity-type
collector
n Reagent consumption was high
n Grade targets were not consistently being met
A technical partnership was established
between ArrMaz and the mineral processor,
which focused on two key areas: collector
formulation customised to their unique feed,
water and process; and process optimisation.
ArrMaz manufactures custom surfactants
designed to improve the selectivity and strength
of spodumene flotation. Laboratory floats on the
processor’s feed samples were conducted in
ArrMaz’s Mulberry, Florida metallurgical lab to
pre-screen the chemistry and formulary types to
meet grade and recovery requirements. A
custom-formulated surfactant-enhanced reagent,
CustoFloat ® 7080, was found to be the most
effective. Selectivity and froth structure were
custom designed to reject iron-containing
contaminants in order to satisfy grade
requirements.
Arrangements were then made to conduct
laboratory tests at the processor’s site to verify
the initial findings. CustoFloat 7080 was proven
to handle the range of varying feed and operating
conditions encountered in the plant. CustoFloat
7080 plant testing was conducted versus the
commodity collectors previously used and the
new collector was found to successfully meet
their grade target of 6%.
A team comprising members from each
company was formed and a brainstorming
session on process troubleshooting was
conducted. Working with the client, ArrMaz
laboratory and process consultants examined
their process from beginning to end, and were
able to adjust feed processing and mineral
conditioning parameters to maximise plant and
reagent performance.
28 International Mining | MAY 2018
Laboratory froth flotation loaded with
spodumene
Over the 3-4 month testing period, CustoFloat
7080 was able to consistently make grade
targets, as well as provide acceptable recovery
and production tons. The following key results
were achieved:
n Flotation selectivity was improved as the ratio
of Li to Fe increased significantly.
n A stepwise process was developed to tweak
operating parameters. CustoFloat 7080
formulary was fine-tuned to better match the
collector and feed.
n Collector consumption was reduced by 68%.
n Collector ease-of-handling and make-down
efficiency was improved.
n During the course of this development effort,
the performance criteria for the site was met,
putting the plant back on track with the
expectations of the prefeasibility study.
“The supplier-client partnership continues
today, now focused on further increasing
recovery with new collector development. Work
on new collector formulas show further
improvement in lithium flotation selectivity over
iron contamination.”
Cyanide Code certified locations
continue to rise
Sodium cyanide and the regulation of its us e has
always been a key topic in mining such is its
importance in gold processing. The best known
and most successful move in this area is The
International Cyanide Management Code For the
Manufacture, Transport, and Use of Cyanide In
the Production of Gold (Cyanide Code), which
was developed by a multi-stakeholder Steering
Committee under the guidance of the United
Nations Environmental Program (UNEP) and the
then- International Council on Metals and the
Environment (ICME) and was fully operational in
certification terms by 2005. Administration of the
code is managed by The International Cyanide
Management Institute (ICMI).
The Cyanide Code is a voluntary industry
program for gold and silver mining companies. It
focuses exclusively on the safe management of
cyanide and cyanidation mill tailings and leach
solutions. Companies that adopt the Cyanide
Code must have their mining operations that use
cyanide to recover gold and/or silver audited by
an independent third party to determine the
status of Cyanide Code implementation. Those
operations that meet the Cyanide Code
requirements can be certified. A unique
trademark symbol can then be utilised by the
certified operation. Audit results are made public
to inform stakeholders of the status of cyanide
management practices at the certified operation.
The objective of the Cyanide Code is to improve
the management of cyanide used in gold and
silver mining and assist in the protection of
human health and the reduction of
environmental impacts.
Recent mining operations certified for the first
time under the Cyanide Code include Goldcorp’s
Éléonore gold mine in Canada (March 2018),
AngloGold Ashanti’s Córrego do Sitio II gold mine
in Brazil (March 2018) and Newmont’s Merian
gold mine in Suriname (February 2018).
Numerous other mines have recently been
recertified, and some have voluntarily withdrawn.
Lastly it is not just mines that are involved,
companies that produce, supply and transport
cyanide are also adopters of the code. Recent
examples of these include a recertification for
Orica’s Bag to Bulk cyanide transfer facility in
Tarkwa, Ghana. The Tarkwa Transfer Facility was
initially certified in full compliance with the
Cyanide Code in March 2011 and was recertified
in October 2014. As required under the Cyanide
Code, the operation was again audited against
ICMI's Production Verification Protocol within
three years of its previous certification by an
independent professional third-party auditor.
ICMI has received and accepted the auditor’s
Detailed Audit Findings Report, which found that
the Tarkwa Transfer Facility maintained full
compliance with the Cyanide Code's Principles
and Production Practices throughout the
previous three years.
In order to maintain Cyanide Code
certification, an operation must meet all of the
following conditions: The auditor has concluded
that it is either in full compliance or substantial
compliance with the Cyanide Code; an operation
in substantial compliance has submitted a
Corrective Action Plan to correct its deficiencies
and has demonstrated that it has fully
implemented the Corrective Action Plan in the
agreed-upon time; there is no verified evidence
that the operation is not in compliance with the
Cyanide Code; an operation has had a verification