MINING CHEMICALS-CHEMICAL CHANGE_proof 25/05/2016 10:33 Page 5
MINING CHEMICALS
Years of experience in chemical injection
applications onshore and offshore have
confirmed the instrument’s capability to reliably
measure fluids under extreme conditions of both
temperature and pressure.”
Litre Meter has long recognised the need for
bespoke solutions for specific flow application
requirements. Fluids differ in viscosities, as well
as chemical and physical properties. Flow rates
and materials also vary. In order to deliver
solutions, it has been necessary to design and
customise flowmeters for each application –
until now.
Litre Meter now keeps in stock design
drawings for 115,000 different VFF flowmeter
configurations. The sheer range of choice has
effectively designed out the need for
customisation. Using pre-existing drawings
means that meters are built and delivered more
quickly with increased efficiencies for the
customer. Lead times are greatly reduced and
customers can bring their projects to fruition and
get them commissioned and online quickly to
minimise delay and maximise production, and
therefore profits.
“Customisation has become more complex
than ever as technologies have been developed
to provide more sophisticated communications, a
wider range of connections and accurate
measurements at higher pressures and over
wider flow ranges – down to very low flow rates,”
said Wemyss.
The paper Durability and Economics of
Materials Used in Design and Fabrication of
Hydromet Equipment was presented by Kevin
Lambrych, Don Kelly and Thomas Johnson;
Speciality Resins, Ashland Performance
Materials, at this year’s SME Annual Conference
in Phoenix in February. They note that
hydrometallurgical equipment “is exposed to
extremely corrosive chemical environments.
Materials of construction must be durable
against corrosion, meet mechanical
requirements, and perform economically over the
life of the mineral processing plant.
“As a material of construction, fibre reinforced
plastic (FRP) has been shown to provide equal if
not improved durability relative to alternative
materials such as corrosion resistant alloys.
Remote fabrication and assembly of process
equipment is also less complex for FRP verses
alloys.”
This paper compared corrosion performance
and cost of plant equipment fabricated with
stainless steel alloys and FRP made with epoxy
vinyl ester thermoset resins. Case histories for
FRP piping, storage tanks, extraction vessels, and
EW cells combined with laboratory based
corrosion studies were reviewed, demonstrating
how FRP materials are selected for
hydrometallurgical equipment.
46 International Mining | JUNE 2016
As part Vale’s of
Long Harbour
project
(Newfoundland),
several FRP
equipment
fabricators worked
with engineering
design teams to
construct the
needed equipment
to process nickel,
cobalt and copper
ores from the
Voisey’s Bay mine. This is just one is an example
of a plant making extensive use of FRP.
The authors explain that “acquisition of
equipment was divided into several packages
and awarded by well known hydrometallurgical
process industry leaders such as FLSmidth and
Clean Gas Systems. Due to the corrosive nature
of the service, all of the FRP equipment for this
project was specified to be fabricated with epoxy
vinyl ester resins. FRP fabricators that
participated in the supply of equipment for this
project included Plasticon Canada, ECC
Corrosion, The Denali group (including Ershigs,
Fabricated Plastics and Belco), and Corrosion
Technology International (CTI). These fabricators
supplied numerous tanks of varied sizes, covers,
scrubbers, miles of pipe, and dozens of EW
cells.”
Another example was the Boleo copper-cobaltzinc-manganese project located in Baja California
Sur, Mexico: a mining project with a large
hydrometallurgical facility that specified a great
deal of FRP equipment. Many FRP tanks of
various sizes have been constructed for this
plant. Some of these were extremely large. Due
to their size, fabricator Ershigs was
commissioned to fabricate nine tanks by filament
winding on site. These tanks were 11.5 m in
diameter by 12.5 m high with domed tops and flat
bottoms.
The authors conclude that “for mineral
processing FRP is more durable, costs less, has
price stability that benefits project planning, and
is easier to maintain than other materials of
construction. FRP has become a material of
choice when designing equipment for the
aggressive conditions found in
hydrometallurgical plants.”
New explosive formulation
For over 60 years the use of ammonium nitrate in
commercial explosives has bee n unchallenged;
however it has some disadvantages. When AN
based explosives do not react efficiently due to a
number of uncontrollable and complex factors,
harmful nitrogen oxide fumes (NOx) can be
generated.
At Boleo, Ershigs supplied ultra-large
hydrochloric acid storage tanks fabricated
using filament winding
Nitrogen oxide and nitrogen dioxide can cause
serious health risks to persons exposed, with
excessive levels of NO2 also affecting the
viability of flora and root systems. “Increased
scrutiny of post blast fume generation has had a
direct impact on the mining industry’s license to
operate,” CRC Mining explains.
“Currently, engineering and administrative
controls exist to reduce the risk of the NOx
hazard. However in order to eliminate the hazard,
researchers from CRCMining and the School of
Mechanical and Mining Engineering of the
University of Queensland have developed and
tested an alternative explosive formulation. This
new formulation eliminates nitrogen oxide fume
emissions by using hydrogen peroxide (H2O2) as
the main oxidiser.”
CRCMining project leader Dr Italo Onederra
said to date over 160 tests have been conducted
to characterise the detonation properties of this
new explosive. Results have shown velocities of
detonation between 2,200 and 5,500 m/s for a
range of densities (0.40 – 1.10 g/cc).
Confined rock breakage tests were conducted
and results published at the Fragblast conference
in Sydney in 2015.
“As part of the program, a prototype system
has been designed to enable the manufacture
and delivery of the product on site. Further tests
continue to quantify product stability and
compatibility with different ground conditions,”
Onederra said.
“This new technology, which replaces
ammonium nitrate, could be a step-change for
the industry. It has the potential to offer different
alternatives and possibilities to mining
companies. It also provides an independent
avenue to conduct explosive and blasting
technology research that was previously the
domain of explosive manufacturers.”
The research is led by CRCMining and UQ with
funding from the Australian Coal Association
Research Program. IM