Quartz is one of Earths most
abundant minerals and occurs in many different geological
settings. It is best known for its use in glass manufacturing,
yet different types of end-markets require differing levels of
silicon dioxide (SiO2) content. Very few deposits
can be classified as high-purity quartz (HPQ), which can be
defined as having at least 99.995% SiO2 content.
According to one of the market
leaders, US-based The Quartz Corp. (TQC), what is really
important when looking at HPQ, is what makes up the other
Its rare to see
SiO2 even quoted on the specification sheet, the
main focus is always on the non-SiO2 content of the
quartz, particularly the alkalis and transition metals,
the company told IM.
The industry standard for HPQ is
defined by a product marketed as Iota, mined by Sibelco, a
Unimin Corp. subsidiary, at Spruce Pine in North Carolina, US.
Iota has set the high-purity benchmark for the rest of the HPQ
market and contains 20 parts per million (ppm) of impurities as
standard, equating to 99.998% SiO2.
Sibelcos purest grade, Iota
8, is 99.9992% SiO2 in composition, containing only
80 parts per billion (ppb) of impurities.
A selection of HPQ projects
Unimin Corp. is the worlds
largest producer of high-purity quartz, but the
confidential nature of its business means it was
unable to provide comment on its operations when contacted by
Producing an industry-benchmark
product, Sibelcos Iota quartz is the product of choice
for semiconductor production as it exhibits properties that
make it ideal for the manufacture of fused quartz crucibles
used in the Czochralski (CZ) process.
The same can be said for its
preference in the production of mono-crystalline silicon solar
cells, which have the highest efficiency among commercial-scale
photovoltaic (PV) products as well as crucibles for CZ single
crystal silicon growth.
Iota quartz is also used for the
production of all types of quartz lighting, including
automotive xenon, halogen, HID and UHP lamps.
TQC is a 50/50 joint venture
created by Imerys SA and Norways Norsk Mineral. TQC is a
merger of Imerys US subsidiaries, KT Feldspar and The
Feldspar Corp., with quartz producer Norwegian Crystallites, to
form a new quartz, feldspar and mica unit.
The company operates from Spruce
Pine, US, as well as Norway, and its products are designed to
meet specific end-market requirements.
The products from Spruce Pine
meet the standards required by the semi-conductor and solar
industry; the products from Norway are tailored to meet the
requirements of the optical and lighting industry, the
company told IM.
The Quartz Corp has permits to
produce 30,000 tpa HPQ at its plant in Norway - which processes
Spruce Pine and Norwegian quartz - however, the company is not
producing at those levels today.
Like most companies in the
HPQ industry, our sales peaked in 2011 due to the boom in the
solar industry, the solar production bubble burst in late 2011
and it has taken almost two years to remove the excess
inventory created in the supply chain and consumption is now
returning to normal levels, the company told
In 2011 TQC invested in improving
the flotation processes at Spruce Pine to upgrade the quartz
quality and also increased capacity to produce more than the
demand of international customers and internal demand in
Norway. The company confirmed to IM that any
future investment will be dedicated to new product developments
In Norway, we have just
successfully commissioned our latest capacity expansion and we
will add capacity in a modular fashion as dictated by demand in
our different market areas, it added.
TQC additionally confirmed that
while its main focus is on the Spruce Pine operation - as no
other area is likely to come close in terms of quality - it
does have an active exploration group who test and survey
many new deposits each year.
[So far] we have not found
any that can match our deposits in Spruce Pine, the
Nordic Mining secured the exclusive
rights for investigation and development of its Nesodden quartz
deposit in Kvinnherad municipality in Hordaland country,
Norway, in 2011. The 600 metre long and 15 metre wide deposit
is a high-purity quartz vein containing more than 3m tonnes
A preliminary estimate for the
deposit has additionally shown at least 2m tonnes hydrothermal
quartz down to 150 meters above sea level.
Unprocessed quartz from Nesodden
meets the specifications for solar silicon production, although
it can be further processed to meet the requirements for
high-purity markets including optical glass, lamp tubing,
crucibles, semiconductors and microelectronics.
Nordic Mining will produce 5,000
tpa HPQ over 30 years from its Neosodden deposit, according to
its scoping study.
The impurities in the raw quartz
average approximately 42ppm in the raw quartz, which will need
to be purified to less than 30ppm or a grade of 99.997%
SiO2 to be considered high purity.
It has been shown that it is
technically feasible to mine the deposit and that high
grade/high value products can be achieved by processing the
quartz, Nordic CEO, Ivar Fossum, explained.
The deposit requires further
drilling for either JORC or NI 43-101 guidelines to be
applicable but the most recent deposit size estimate, given in
2011, indicated a minimum tonnage of 1.2m tonnes high grade
(>90%) quartz and 0.77m tonnes quartz in the surrounding
The mine will require $50m
investments and assigning total mining operating and
transport (...), the rate per tonne is estimated to vary
between $19.5 (strip ratio 2.2) and $25 (complication due to
geology) per tonne, the scoping study outlined.
In January 2013, the company
revealed that the project would require further drilling and
processing test work as well as investigation of by-products
rising from the 51,000 tpa waste (which will include some lower
grade quartz) that will need to be disposed of.
We will put effort into
advancing project development in the coming year. Initially,
focus will be on commercial issues to position the project
towards markets and customers, said Fossum.
Mauritanian Minerals Group Co.
(MMC) produces and markets HPQ from Mauritania under a 30-year
renewable licence to operate, obtained from the Mauritanian
The companys open pit mine is
located 130km from the port of Nouadhibou and stretches over
557km2. A geological survey revealed a vast resource
of 99.9% purity quartz, capable of producing 100-500,000 tonnes
for the first year.
Our mission is to develop a
range of quality and extremely competitive [products] in the
global market for high-purity silica, the company
End markets for MMCs product
include solar thermal energy, automotive glass and
construction, as well as high tech industries including medical
ceramics, LCD touch screens and laboratory equipment.
Creswick Quartz Pty
Based in Victoria, Australia,
Creswick Quartz has been conducting operations since 1996. The
company processes quartz from old gold mine tailings at its own
In the past, Creswick Quartz has
supplied lower-purity quartz to end markets including glass
manufacture, composite stone, silicon metal, water filtration,
ceramics and agriculture.
In future, Creswick Quartz hopes to
build a new processing plant to introduce ultra-pure quartz
material, which has been confirmed by independent analysis.
This quartz deposit is thought to be low in impurities,
especially boron and phosphorus. Physical and chemical
treatment has revealed tailing purity of 99.995%
SiO2, which could eventually reach purities of
The volume of above-ground quartz
is in excess of 1m tonnes and is thought to be of uniform
quality. The licensed area below ground is around
Applications for this material
include semiconductor and crucibles and upgraded
metallurgical-grade silica (UMG-Si).
Customers are mainly based in
Victoria; however, the company has now begun to supply
end-users outside the state.
Idaho-based I-Minerals is
developing two projects at its Bovill Kaolin deposit, which
produces several mineral products including feldspar,
halloysite, kaolin and quartz. The quartz developed here
displays three levels of purity in excess of 99%
SiO2, with the highest grade defined as HPQ at more
than 99.98% SiO2 purity.
End-markets targeted by I-Minerals
include sodium silicate, paint, solar glass, optical glass, art
glass, glass bulbs and liquid crystal display (LCD) glass.
Beneficiation of raw quartz into
refined high-purity products is required to minimise the
specific impurities of the individual raw quartz. This process
is often adapted depending on the end-use application the
producer has in mind, as some uses require a higher-purity
product than others (see table 2).
According to Dorfner Anzaplan, the
internationally accredited German laboratory with extensive
experience on HPQ processing and analysis, some HPQ
applications are becoming more restrictive in their
specifications for very low boron and phosphorous content.
It is very difficult to
analyse such small parts per billion amounts of these
impurities, so you need a lot of experience of working with HPQ
to be able to do this, Dr Reiner Haus, Dorfner Anzaplan
managing director, told IM.
The key to analysis is not
only the ability to measure the levels of impurities in the
quartz but also the sample preparation. Lots of mistakes can be
made when preparing samples which can introduce impurities into
the HPQ, he added.
Speaking more specifically about
HPQ processing requirements, Haus explained that there is no
standard technology route to making HPQ.
For HPQ, you have to
investigate the composition of the quartz very carefully and
develop a process design based on the specific characteristics
of the quartz, he told IM.
Unlike some industrial mineral
markets, competition in HPQ is limited, meaning pricing remains
fairly steady. However, this mineral does not come cheap.
Speaking at the Middle East
Industrial Minerals conference in Oman this November, Haus told
delegates that one tonne of quartz can be equivalent in price
to one automobile at almost $10,000 for outstanding high-grade
Dorfner Anzaplan noted that it
usually notices a year-on-year increase in HPQ prices, while
TQC told IM that further increases could soon
be on the horizon.
Excluding the 2011 solar
boom, which created a price bubble in some segments as demand
exceeded supply, the market price for HPQ has been stable
overall. However, external cost inflation (such as the cost of
HF acid/fluorspar, which is a large component of total product
cost) could justify an upward adjustment of HPQ prices in the
future, the company said.
Anzaplan agreed that the solar
industry has had some impact on prices in the last two years
but noted that we think that this will return to levels
we have seen in the past.
The company added that changes in
prices for the chemical aids used to process HPQ may influence
product prices, but that these are mostly stable for now.
Fluorspar used in the
treatment of HPQ has seen some movement, however, and changes
in the price of HF will impact HPQ, Haus conclud
Situated in the heart of the Appalachian Mountains in North
Carolina, US, the Spruce Pine mining district has long been a
source of mineral wealth.
The granite rocks were first
recognised for sheet mica, which was used as electrical
insulation in early vacuum tube electronics. Now, however, HPQ
is a big focus for mining companies including Unimin and The
Quartz Corp., although the deposit is also recognised for its
The alaskites of the Spruce Pine
district were created approximately 375m years ago from magma
several miles below the earths surface. Nowhere else in
the world have the mineral forming processes yielded an
equivalent HPQ ore, meaning those working at the Spruce
Pines deposit dominate the HPQ market.
However, others are working on HPQ
projects in other locations (see table 1), developing
a product specifically designed for individual market uses.
Smaller developers include
Russias KGOK JSC, Creswick Quartz Pty Ltd, Australia;
I-Minerals, US; Momentive Performance Materials, Germany and
the US; Nordic Mining, Norway; and Mauritanian Minerals Co.,
Chinese quartz has not yet been
qualified to the Iota standard, although producers are working
towards this with companies such as Dorfner Anzaplan - an
internationally accredited German laboratory with extensive
experience on HPQ processing and analysis - to obtain the
technologies and processes that can improve quartz
HPQ end markets
High purity quartz is a
speciality feedstock used in a variety of different end
Fused quartz crucibles are
used for the manufacture of silicon metal ingots, which can
later be processed into silicon wafers for photovoltaic (PV)
cell and semiconductor markets.
The solar industry played a
big part in HPQ demand in the 10-year period leading up to 2011
as a reduction in the price of silicon (used to manufacture
mono-crystalline and polycrystalline solar cells) coupled with
a push for renewable energy in the US, Europe and further
afield, spurred a large amount of solar uptake.
In the last two years,
however, the PV industry has taken a knock as reduced
government subsidies and a global economic downturn slowed the
amount of new projects, which had an impact on the demand for
The market that has
demonstrated the greatest volatility of demand has been the
solar industry, TQC told IM.
The peak for demand in this
sector was in 2011 and it is unlikely that we see this level of
demand again until 2016, the company added.
Despite this, Dorfner Anzaplan
remains optimistic about the future potential for demand to
We expect to see
consolidation in the PV industry within the next five years,
and certainly by 2015, however, because there is lots of solar
installation taking place around the world and we think we will
be back where we were in 2011 before long, Haus told
The process for making
semiconductors is very similar to manufacturing solar cells -
which is one of the reasons many semiconductor companies
switched lanes when the semiconductor market slowed in around
2008 when the PV market began to boom.
In this cyclical market, thinner,
more efficient product innovation is again expected to drive
demand for HPQ.
New generation 300mm-450mm
wafers for semiconductors is driving demand for HPQ-glass-based
materials, which are used to manufacture these wafers,
High temperature lamp
High-temperature lamp tubing, such
as mercury and halogen lamps, uses a high purity quartz
envelope to contain the lighting components.
In the lighting industry,
compact fluorescent lights (CFLs) are competing with halogen
lamps for market share, but halogen lamps outperform CFLs in
colouring and the fact that they do not contain mercury,
We are also seeing demand
increasing for metal halide lamps for car headlights as
automotive ownership increases and consumers opt for high-spec
vehicles, he added.
Haus further explained that in
telecommunications, Dorfner Anzaplan is seeing the expansion of
the broadband market and increasing investment 3G/4G
infrastructure worldwide. HPQ is used in the handling of
waveguides for this industry, so the company is also witnessing