MINING CHEMICALS
Another case study looking at a trial of
AEROPHINE 3418A on a 4,000 t/d copper-zinc-
silver mine that previously used potassium amyl
xanthate provided evidence of the collector’s
precious metals recovery credentials.
The 10-month test pitted metallurgy obtained
with the standard promoter against the
performance of a mixture of AEROPHINE 3418A
promoter and potassium amyl xanthate.
Looking at the monthly silver tailings assays as
a function of head grades for nine of 10 months, it
was evident there was a trend to lower silver tails
assays with the AEROPHINE 3418A/potassium
amyl xanthate combination. The average
metallurgy over the ten-month period also saw the
use of AEROPHINE 3418A promoter increase silver
recoveries by 6%, according to Solvay.
“Small but significant improvements in copper
metallurgy were also observed together with a
small reduction of zinc reporting to the copper
concentrate,” Solvay said.
Revadep proves its worth
highly effective in the PGM flotation process by
reducing floatable gangue like talc.
The company is also targeting the Zambia
copper flotation market with its Revadep Cu++
depressant formula, according to Thomas. “Highly
floatable carbon is also a problematic mineral in
some operations in Zambia and the Axis House
carbon depressant, Cu++, was successfully trialled
at full scale,” she said.
In the DRC, the company’s mobile precipitation
plant, built specifically for cobalt miners to analyse
the effects of dosage, process conditions and
reagent type on different types of ores, is starting
to be appreciated by miners too, Thomas said.
And, the development of a reagent range to
remove cadmium in phosphate production has
allowed Axis House clients to cost-effectively
sustain phosphate output without bolting on
processing units like ion exchange columns, she
added.
At the R&D stage of its Revadep depressants,
Axis House is addressing the use of one of the
more controversial reagents used across the
mining industry, according to Thomas.
“At development level, the focus is to expand
the Revadep range to include selective
depressants of sulphide gangue (pyrite,
pyrrhotite) to replace or reduce the use of
hazardous reagents like cyanide,” Thomas said.
Axis House’s Oosterndorp says its clients can
benefit from increased metal recoveries while
improving the working conditions of their staff and
streamlining their processes with the
implementation of its environmentally sensitive
products.
As Cherry Thomas, Sales Manager, Africa, says:
“Environmental regulations are…becoming stricter
Automating cyanide control
and requests for alternative reagents to common,
Speaking of cyanide, Orica says its Cyanide
but hazardous, chemicals (xanthates, NaHS,
process review and optimisation services have
cyanide, etc) are increasing.
recently helped a customer in Peru achieve
“Axis House takes this into consideration during
significant reductions in cyanide and hydrogen
the reagent development work for clients.”
peroxide consumption, all while increasing gold
Its xanthate-alternative sulphide collectors are
recoveries.
being used successfully at a several copper mines
Reducing reagent consumption offers
in Zambia, as well as platinum and gold mines in
significant and sustainable cost benefits to
South Africa, according to Oostendorp.
operations but comes at the risk of lower
“The European and Middle East market has
recoveries and greater disruption to process
shown substantial growth in the last 18 months,
chemistry due to ore variability, Orica says.
an area where we are focusing our resources to
This is where Orica’s process review and
maximise on the market potential,” he added. This
optimisation service, PRO Service, comes in.
has seen multiple trials conducted and completed
A collection of tools and services developed to
at copper-lead-zinc mines in Europe and Turkey,
where sulphide collectors were successfully
trialled in full-scale applications.
Thomas said: “This allows Axis House to apply
the application knowledge and market products to
operations processing similar ore types.
Successful application of reagents also forms a
new baseline from which further development can
take place.”
Sulphide collectors are not all the South Africa-
based company is working on.
The company’s Revadep depressants range,
engineered to target specific gangue minerals in
the flotation process, has found favour with
platinum group metal producers in Africa.
Orica’s PRO Service methodology
Thomas said the depressants have proven
38 International Mining | MAY 2020
support the gold industry in achieving best
practice in gold leaching and recovery, the PRO
Service package uses tailored solutions from Orica
including the Process Health Check benchmarking
service, LeachIT™ process simulation and
Cyantific™ process analysers.
Process Health Check enables customers to
identify problem areas where improvements will
lead to significant gains in metal recoveries and
savings in reagent consumption. It uses a
customer’s historical data to benchmark their gold
solid and solution losses against similar sites
around the world. It also analyses incoming
variables, and how well they are controlled, to
produce the desired outcome – maximum
recoveries at minimum cost.
The same historical data can then be used with
LeachIT – an intelligent software package that
allows metallurgists to see how their process will
respond to changes without time-consuming and
expensive experiments. “Aimed at enabling best
practice leaching, LeachIT simulates changes to
the process and presents the impact on tails
grade,” the company said. “The software harnesses
this information not only to calculate but also
visualise gold recovery and cyanide consumption.”
Cyantific uses a range of online process
analysers to optimise cyanide addition,
detoxification processes, and tailings discharge –
lowering costs while maintaining or improving
recovery, Orica says. Customers with a properly
installed and maintained OCM5500 Leach Process
analyser typically reduce cyanide dose to the
leach by 5-20%, according to the company.
Orica’s Customer Solutions Manager – Global
Cyanide, Paul Martin, said: “We aim to take our
customers’ operations data and combine it with
our expansive global Cyanide process data
gathered over time, and then interpret that data
into insights, delivered visually so that our
customers can make more rapid and confident
decisions.”
At the open-pit gold mine in Peru, Orica was
able to demonstrate how its PRO Service enables
consumption savings and increased gold recovery.