All metals are sourced from ores,
and all ores contain impurities. For metal producers, unwanted
minerals are an inherent part of the production process and
impurities must be removed prior to the metal reaching its
The simplest method of removing
impurities from metallic ores is with the addition of a
metallurgical flux during the smelting stage of metals
production. The primary purpose of a flux is to react and
combine with unwanted minerals in the metallic melt to form a
slag that can be separated from the metal and removed from the
Fluxes are a key component of the
metals production process and without them metallic products
could not exist; yet few minerals meet the demanding criteria
of this market. Considering their importance in metals
production, it is somewhat ironic that flux minerals are
considered to be a niche market by many industrial minerals
Slab scarfing: the surface of the steel block is
treated prior to rolling. Courtesy ThyssenKrupp AG
The principal flux minerals are dolomite, fluorspar, lime and
olivine, with smaller amounts of bauxite, silica and
wollastonite also used (see panel).
Demand from the flux market for
each of these minerals differs, with perhaps fluorspar, lime
and olivine the most strongly tied to this particular aspect of
metals production. Although other minerals (such as bauxite)
are dependent on the metals market for a number of reasons (ie.
ore, refractories) their use as a flux is estimated to be less
than 1% of total production.
The metals market (particularly
aluminium and steel) is well-known to be cyclical, and the most
recent example of this has been the past 18 months in the
industry. The market during the first half of 2008 was a
bonanza for aluminium and steel; both metals reached record
production highs and prices were hugely inflated.
Increased metals production
required increased flux consumption, and for many flux minerals
2008 was a record year for production and prices. Yet towards
the last few months of 2008 all that came crashing down.
Using aluminium as the example:
between July 2008 and February 2009 the London Metal Exchange
(LME) cash price for aluminium plummeted 62%. The all-time high
of $3,291/tonne reached on 11 July 2008 had, by 24 February
2009, collapsed spectacularly to $1,253/tonne.
A dearth of demand for
metallurgical fluxes, similar to refractory minerals,
characterised the period from late 2008 through to mid-2009,
and producers also had to contend with substantially lower
prices for their products.
From July 2009 onwards the
situation improved. The World Steel Associations figures
started to show a turnaround. Initially this was a shallower
decline in global steel output, but it was followed in later
months with year-on-year production increases.
In October 2009 global crude steel
output was up 13% on 2008 levels, although this was mainly
driven by a 42% jump in Chinese production (
IM 20 November 2009: October steel output rises
A market in flux: lime
This market U-turn was particularly
difficult for lime and dolomite producers. Iron and steel are
the two most widely produced metals in the world and their
primary fluxing agents are lime and dolomite. Global production
of these two minerals is vast and the flux market consumes
almost half of all lime produced (around 130m. tpa
- see Table 3).
Owing to its MgO content dolomite
is an important refractory mineral, and dolomite fluxes (and
their calcined counterparts) are primarily used to extend the
life of refractory linings and bricks (see panel).
Dolomite is also used to manufacture an array of primary
Consequently, lime and dolomite
producers rely heavily on metallurgical markets (and steel in
particular) to drive consumption.
One USA-based lime and dolime
producer told IM: Obviously, the
reduction in steel production has led to a corresponding
reduction in lime and dolime consumption. As a result, there
have been numerous kilns throughout North America which have
been placed on idle. In general, these kilns can be brought
back online easily and in tandem with increased steel
All too often has the effect of
reduced consumption been seen in the financial results of lime
producers. The worlds second largest lime producer,
Carmeuse Group of Belgium, reported a net turnover of
709.1m. in its Q3 2009 financial results, representing a
fall of 30.4% on Q3 2008 levels. Carmeuse cited a sharp
deterioration of the economic environment for the fall in
revenue and said that crude and calcined products alike had
Following the publication of its Q3
2009 results, Carmeuse announced that it had undertaken a
refinancing programme which had been approved by backers. The
group also revealed that at the end of June 2009 Carmeuse had
breached a portion of its agreed bank covenants for the first
time in the groups history.
Due to the economic crisis
and its significant impact on certain of its clients like the
steel or construction sectors, the group is facing a
significant reduction of volumes sold since October 2008,
United States Lime & Minerals
Inc. reported decreased sales volumes for the first nine months
of 2009 owing to reduced demand for lime in construction and
steel markets. The company countered the sales fall with price
rises for lime and limestone, which on average were increased
Mississippi Lime Co. also
introduced price increases of 10% in September 2009 for its
standard quicklime and hydrated lime products, in order to
recover ongoing cost increases, support continued
investment in the business and maintain the quality and
reliability of supply.
But is the situation changing? In
October 2009 Finland-based Nordkalk Corp. was given the
go-ahead to develop a 2.5m. tpa limestone mine on the Swedish
island of Gotland, with 60% of this material destined for the
steel flux market.
Anders Mattsson, Nordkalks
managing director, told IM that the company
had been given a 25-year permit to mine 50-60m. tonnes of
limestone, with the option to apply for an additional permit
that would allow the mine to go deeper and extend to 80-90m.
Fluorspars role as a flux in
both steel and aluminium production has seen it hit doubly hard
by the reduction of the worlds metal output. Low grade
metspar and high grade acidspar are consumed by these markets,
with almost 70% of total fluorspar production destined for
metals consumption (Table 3). As a result prices for
all grades of the mineral closely followed the turbulence in
the aluminium and steel prices over the past 12 months
Several papers at
IMs Fluorspar 09 conference in Valencia,
Spain in November 2009, addressed the issue of pricing and
demand from metallurgical markets and gave estimates for
short-term and long-term metals production (
IM December 09, p.9: Metals fortify
UK-based economics consultant,
James King, gave a comprehensive forecast indicating that
AlF3 markets could account for a 4% growth in
acidspar demand in 2010, while figures for consumption in 2030
placed fluorspar demand at almost 50% higher (an additional
1.05m. tonnes) than present levels.
Meanwhile, a bullish growth figure
of 10% was forecast by King for fluorspar demand from steel
markets in 2010. Elsewhere, Kings long-term steel
forecast indicated that an additional 1.77m. tonnes could be
required in 2030 Ð that is, if EAF steel output reaches
Kings estimate of 840.1m. tonnes, more than 50% higher
than production in 2008.
These figures were debated by
Michael Reynolds, director of MS Reynolds Srl, who suggested in
his presentation that AlF3 prices are likely to fall
before they increase, owing to a possible surge in exports from
Reynolds proposed that adoption of
an aggressive export policy by China could bring
world AlF3 prices down to the range of the lower
cost Chinese product and saturate the market leaving
little room for western AlF3 producers.
There are a lot of
uncertainties in the main metal markets nowadays, and the long
recession has made peoples nerves brittle,
commented Dawei Mi, general manager of Chinese fluorspar
producer Tianjin Steyuan Minerals Co., Ltd (Steyuan).
[These uncertainties mean] we
are unsure about the market trends. Concerning fluorspar, the
Indian market was active in the first half of this year but it
became quiet from July until now. Meanwhile, the European
market recovered in the second half of 2009, Mi told
Steyuan, based in Tianjin, around
170km south-east of Beijing, is an international producer and
exporter of a range of industrial minerals, including
fluorspar, graphite, calcium aluminate and caustic calcined
The company owns three
subsidiaries F&C (HK) International Ltd, Jenny Mineral
Resources International Ltd, and Steyuan (Mongolia) I/E Trading
Co. Ltd. It supplies metallurgical grade fluorspar from
Mongolia, with a capacity of 2,500-4,000 tpm.
Steyuan says demand for its high
grade fluorspar has exceeded supply since the second half of
2008, while demand for its lower grade metspar has been
moderate. The company expects demand to remain at
these levels throughout 2010, so long as the market does not
suffer exceptional circumstances.
Mi told IM:
Different from other industrial products, fluorspar is a
natural ore and it is difficult to control its quality when
processing. With a qualified supply and a perfected method of
production, the quality control is guaranteed. Then, the
product can be competitive.
Regarding fluorspars use as a
metallurgical flux, Steyuan believes it is still a crucial
market: Steyuan is promoting calcium aluminate to replace
fluorspar in [steel] slagmaking, but fluorspar is indispensible
in fluxing at present, Mi commented.
We hope industries reduce the
usage of fluorspar and we look forward to new technological
innovations to replace fluorspar in fluxing. In doing so, we
wish to contribute to environmental protection and the
sustainable development of society.
Calcium aluminate is viewed as a
potential substitute for fluorspar fluxes in steelmaking. The
material itself can be sourced from slags formed from
alumina-based fluxes used in a basic (lime-bearing) system;
essentially calcium aluminate is a recycled material.
Steyuan is making great
efforts to promote the use of calcium aluminate while supplying
fluorspar, Mi told IM. In this
way, we not only meet customers demands for raw materials
but also guide their demands in accordance with the trend of
Steyuan sources calcium aluminate
from plants in Henan and Liaoning provinces and has invested in
one of the local plants to ensure the quality of the product is
high. The companys calcium aluminate capacity is around
2,000 tpm and the product has a typical chemical composition of
45-51% CaO, 35-45% Al2O3, 5% max.
SiO2, 2% max. Fe2O3, and 10%
Mi believes that calcium aluminate
can fully meet the metallurgical requirements of a
flux and that it has some benefits to using fluorspar, such as:
consistent chemical composition; low melting point, short
smelting time, low viscosity; and decreasing damage to
Olivine may be a small volume
product but, thanks to its refractory properties, it has some
major consumers. Around 65% of total production is estimated to
be diverted to the flux market (Table 3), while the
remaining amounts are used in markets for refractory bricks and
castables, foundry sand, EBT taphole filler, CO2
sequestration, and in abrasives, among many others.
Norway-based North Cape Minerals
A/S (NCM), a wholly-owned subsidiary of Unimin Corp.
(ultimately owned by SCR Sibelco NV), is the worlds
largest producer of olivine. The company owns three olivine
mines in Norway - Aheim, Bryggja, and Raubergvik - which
produced 2.4m. tonnes in 2007.
The companys olivine
operations have been significantly affected by reduced demand
and in summer 2009 NCM announced that it had temporarily
suspended the plants at Bryggja and Raubergvik, leaving only
Aheim unaffected (
IM 21 July 2009: NCM suspends olivine mines).
The temporary closure of Bryggja
could last as long as five years, but NCM commented: At
the current low production volumes, [these steps] will allow a
sustainable development of the resources and secure future
competitive power and creation value.
Meanwhile, in November 2009, NCM
announced that its ownership of Turkish olivine producer
Beykrom Mining Co. had been transferred to Turkish feldspar
producer Cine Akmaden, now owned by parent Sibelco (
IM 4 December 2009: North Cape merges with
The future for NCM is also
changing, as from 1 January 2010 NCM will be merged with
industrial minerals producer Askania AS, which was bought by
Sibelco in 1992. Askania supplies a range of minerals including
bauxite, bentonite, olivine, and zircon flour.
Falling olivine consumption also
contributed to the bankruptcy of Norwegian olivine producer,
Steinsvik Olivin AS. Steinsvik began olivine extraction in 2004
from a deposit near Dalsfjord, west Norway, and operated with a
150,000 tpa capacity; but in September 2009 the company was
Svein Parr, managing director of
Steinsvik, told IM at the time that bankruptcy
had been the only solution for the company, largely owing to a
lack of market volume for olivine and financing of
production in the original company.
One olivine company bearing up well
in the depressed economy is Swedish minerals producer Minelco
AB, which celebrated 20 years service in September 2009.
Minelco is the worlds second largest olivine producer,
operating from the Seqi deposit in Fiskefjord, west Greenland,
with a capacity of 1.1m. tpa.
A significant portion of
Minelcos olivine is believed to be captive; supplied to
parent company, and leading iron ore producer, LKAB of Sweden.
Industry sources estimate that prior to Minelcos purchase
of the Seqi deposit in 2005, LKAB sourced around 300,000 tpa of
olivine from Minelco rival NCM (
IM November 09, p.44: Olivines future in
flux). The majority of the companys olivine
production is shipped to Norway, with smaller amounts
transported to the Netherlands, the UK and the USA.
Pasek Espana SA is Spains
only producer of dunite (a magnesium silicate mineral
containing olivine). The company operates two dunite mines in
Cabo Ortegal, Galicia, in the north-west of the country, with a
capacity of around 1m. tpa. Pasek produces dunite for a range
of markets, including as a slag conditioner for blast furnaces
and taphole sand for eccentric bottom tapping.
Javier Martinez, Paseks
managing director, told IM: Pasek
delivers dunite for steelmaking through the blast furnace
route. In this market we have followed the downturn on
production through 2009 and expect to follow the volume
recuperation trend that will come in 2010, as blast furnaces
are being started up all through Europe.
Martinez explained that the company
has seen a trend from its clients towards more detailed studies
of fluxes as a small but very important part of the mix.
As a result there have been some developments in the way
that MgO is added to the process of steelmaking,
The company believes that there is
a clear movement to reduce the addition of MgO to sinter plants
in favour of direct addition into the blast furnace.
Under these operating
conditions we see many of our customers predictions and
test proposals for next year moving to our bigger grain
products, Martinez revealed. We expect to benefit
from this situation since coarse dunite is the best available
flux to be handled directly into the blast furnace. It is also
the most effective way to remove sulphur and evacuate alkalis
from the pig iron together with a higher Fe content and a
reduction of coke consumption.
Table 2: Mineral
fluxes and their applications
Source of alumina for acid
and basic applications. Alumina-based fluxes function
amphoterically and thus can either neutralise bases or
acids forming aluminium silicate in high-silica
slags or calcium aluminate in lime-bearing slags.
||Specialised flux, used in EAFs in a mixture with
lime/dolime as a viscosity modifier and desulphuriser to
EAF slags. Also used in the BOF and in secondary steel
refining, particularly AOD converters. Use of fluorspar
in steel has decreased over past decade.
|Acidspar is used to manufacture aluminium
fluoride (AlF3), from which cryolite (Na3AlF6) is
produced. Along with fluorspar, aluminium fluoride and
cryolite are used in a molten bath to dissolve alumina
and recover electrolytic aluminium.
||Lime can be used in sinter production. It is more
expensive than limestone but can have advantages, such as
increasing sinter plant productivity. Main use is in BOF
and EAF for slag formation, often as a lime/dolime blend.
Both are also used in combination with fluorspar in
secondary steel refining and the EAF. The use of dolime
as well as lime speeds up slag formation and helps to
extend refractory life.
|The benefit of using a lime flux in EAF
steel is that it forms a slag which can be separated from
the steel and poured from the furnace as a liquid. Lime
also reduces refractory wear and gunning.
|In parts of the world where dolime is not
easily available, lightly calcined, briquetted magnesia
has been used. Because of lower reactivity this has not
been entirely successful.
||Most widely used flux minerals. Ground limestone or
dolomite is mainly used to make sinter and pellets. Can
also be added in lump form to blast furnace with lump
iron ore or pellets, where amount depends on proportion
of flux already in the pellets.
||Mainly a magnesium source in the blast furnace. Can
be used as direct charge (sand or lumps), in
olivine-bearing iron ore pellets, or in sinter. Reduces
amount of coke needed in blast furnace. Used more in
Europe due to availability of low silica magnetite ore.
North American use of higher silica taconite means more
dolomite is used instead.
||Primarily used in non-ferrous metallurgy where slags
are based largely on formation of iron silicate. Silica
is the primary flux for copper smelting where its forms a
fayalite slag during flash-smelting.
Main use is as a component
of tundish and continuous casting mould powders. These
form a solid layer on top of the liquid slag and molten
steel below, thermally insulating the molten steel,
preventing solidification. Also prevents steel reacting
with atmospheric gases, and lubricates the steel as it
passes through the mould, preventing sticking. Key
production in China, India and USA.
Wollastonite finds the majority of
its market usage as a high performance filler in plastics, with
other uses in coatings, ceramics and glass. A smaller, but
significant market for the white mineral is as a powder for
tundish and continuous casting moulds in steelmaking and a
lubricant for molten ore, with around 10-15% of wollastonite
used in this application (Table 3).
The global supply chain is heavily
concentrated between a few major players such as Wolkem India
Ltd, Chinas Lishu Dadingshan Wollastonite Co. Ltd, and
USAs NYCO Minerals Inc.
One relative newcomer is
Spains Crimidesa Group, owned by Compania Minera
Ilustracion (CM), which produced 20,000 tonnes in 2008. The
company has focused its wollastonite production on the ceramic
and container glass markets but supplies some material to the
metallic flux industry (
IM November 09, p.44: Wollastonites pins and
Jose Arribas, quality manager for
CM, told IM: The outlook for metal
production (and flux consumption) in 2010 is not very positive
as the metals demand is still weak and the prices are low. This
is due in part to the Chinese pressure that reducing stocks to
all cost are eroding the international market.
Arribas explained: Speaking
more precisely about metallurgical fluxes, I see a bad outlook
as some metal producing plants in Spain are closing and the
production rate has been reduced in the rest, so all related
products should suffer the same fortune.
Table 3: World production
of main flux minerals
||2008 (m. tpa)
||Flux use (%)
||Flux use (m. tpa)
By volume lime is the most widely used mineral in metallurgical
fluxing, with around 45% of total production sold into the
* US production, untreated, uncalcined
** not including untreated, raw
Source: Industry estimates, US Geological Survey
It is inevitable that the market
for the three major metals will recover - indeed downturns
are expected in this cyclical industry - but for now the
focus of metals and flux producers is on when and
where demand will recover first.
Aluminium demand appeared to
rebound in Q2 2009 largely owing to the restart of Chinese
smelters. At the time industry participants were concerned that
the production restarts were a result of artificially high
prices and not in response to true demand returning (
IM July 09, p.40: Chinas bauxite
More recently estimates of the
aluminium market indicate that inventories which were at
an all-time high in June 2009 have actually begun to dry
up, creating uncommonly high prices in December 2009,
particularly in North America, according to reports in
Aluminium demand recovered in
the second half of 2009 after a sharp fall, with a particularly
strong rebound in China. Producers in China responded to this
by a sharp increase in smelter production, raising demand and
creating a tightness in markets for raw materials, James
King, economics consultant, explained to
Metal stocks remain extremely
high, but the market is ignoring those and aluminium prices are
strong. Production may now be growing too fast for the
underlying state of the market and western smelters need to be
cautious about restarts, King warned.
King anticipates that, in the
short-term, there may be a correction to prices as stocks
continue to rise, but by the second half of 2010 and into 2011
strongly rising demand should permit the industry to resume a
normal level of capacity utilisation.
But what about iron and steel?
Metal Bulletin reports that the US pig iron market is
described as lacklustre at present, yet Brazilian
pig iron producers exporting to the USA are refusing to
compromise on prices setting the bar at $325/tonne FOB. It
is a matter of who blinks first.
Speaking on domestic [US]
steel markets only, the outlook is entirely subject to the
overall economic recovery, one US lime producer told
IM. Predictions from industry insiders
generally yield modest recovery estimates until 2012. Sustained
improvements in the automotive, residential and commercial
markets will drive steel production.
Globally speaking, the world steel
demand was seen to be recovering strongly from mid-2009
onwards. Producers in many countries began to restart some of
the huge quantity of capacity that had been idled in late 2008,
with China leading the way.
Demand growth was strongest
in China, but elsewhere was much more modest, King
commented. Rising steel production created tightness in
the market for steelmaking raw materials (iron ore, coal and
scrap), raising the costs of steel production. By late 2009
steel production began to look excessive in relation to real
demand and steel prices started to weaken.
King explained: Steel
producers are therefore under pressure from rising costs and
falling prices and the recovery of production may stall for
some months. Underlying growth in demand across many markets,
still led by China, is likely to require further restarts of
idle steel capacity in 2010 and normal operation of the
industry by 2011.
So what does this mean for flux
minerals? In the short-term China will continue to be the
primary driver of metals production and thus the primary
consumer of metallurgical fluxes.
The rest of the world, particularly Europe and North
America, has been slower to show signs of recovery.
Consequently, flux consumption in these areas is likely to
remain low until there is any true demand for metals from
end-user market segments and that will require recovery in
the automobile and construction industries.
Figure 2: Crude Steel:
World Production by Process
Source: James King, 2009
Metallurgical fluxes at a glance
A metallurgical flux is an additive
for purifying and improving metallic ores. Its primary purpose
is to combine with impurities in molten ore (such as
phosphorous, silica, sulphur, zinc) to form a slag that can be
separated from the metal. Other benefits of metallurgical
fluxes include: decreasing viscosity and aiding lubrication,
neutralising acidity of the metallic melt, preventing reaction
of the melt with atmospheric gases, and slag conditioning.
In slag formation, using the
correct flux will create a lower density slag that is
immiscible with the molten metal and can be easily removed. The
slag comprises the original flux mineral combined with
impurities from the ore. As there are a number of different
ores (which are destined for different end products), the type
of impurity needed to be removed is variable (ie. ferrous
versus non-ferrous metallurgy).
As a consequence, there are three
main flux types, with several minerals falling into each
category: acid, basic and
neutral (Table 1). A
basic system is that of steelmaking, because its
primary fluxes are bases limestone and dolomite (and their
calcined counterparts) while non-ferrous metals (eg.
aluminium, copper) are treated as acid
Table 1: Mineral fluxes and their applications
Source: Industrial Minerals and Rocks, 7th
Industrial minerals are used
throughout all aspects of the iron and steel production
process, from the initial preparation of iron ore pellets (that
are bound with bentonite) through to continuous casting (where
steel is lubricated with a wollastonite flux).
In sinter production,
olivine and lime are
typically supplied to sintering plants and as direct feed for
blast furnaces. Magnesia silicates (ie. olivine) are commonly
used as blast furnace fluxing additives, not only to adjust the
slag MgO content, but also to promote potassium elimination
with the slag, and limit the harmful accumulation of potassium
in the stack.
In basic oxygen steelmaking, molten
iron is charged from a blast furnace into a refractory-lined
furnace, where it is injected with oxygen at high
speeds resulting in oxidation of carbon and any
typically added to the BOF steel mixture after the beginning of
oxygen injection, where it reacts with impurities (primarily
silica and phosphorus) to form a slag which is later removed.
The lime needed to manufacture one tonne of steel ingot is
Steel plants tend to use a high
calcium quicklime flux, yet most of the basic oxygen plants
substitute or add 30-50% dolime, as the
magnesia content of the dolomitic material helps to extend the
life of the refractory lining in the furnace. Dolime for BOF is
in the range of 10-40mm in size.
Fluorspar is a
neutral flux (the reaction product of a base and an acid) which
has traditionally enjoyed high rates of usage in steelmaking,
where it is used to improve fluidity. Over the past decade its
use as a flux in steel has declined, but higher grades of
fluorspar (acidspar) are very much in demand for the production
Wollastonites main use is as a component
of tundish and continuous casting mould powders. Wollastonite
also prevents steel reacting with atmospheric gases, and
lubricates the steel as it passes through the mould, preventing
Electric arc furnaces (EAFs) are
used to produce steel from scrap. Scrap steel, plus iron ore
and beneficiated iron ore, is placed in a furnace and melted by
heat from an electric current.
A lime flux
comprising quicklime or a blend of quicklime
and dolime is added, with the total flux
amount used varying between 50-120lbs/tonne of steel. Dolime
may account for up to 50% of the flux, and is typically added
in 5-20mm size fractions.
Although lime and
dolime are also used in non-ferrous
metallurgy, the principle fluxes in this area are
alumina, fluorspar and
The primary non-ferrous metal is
aluminium, which consumes large volumes of acid grade
fluorspar for its production.
Smelting and refining of copper and other non-ferrous ores
can produce noxious SO2 gas fumes; these can be
neutralised in scrubbers by passing through a dilute hydrated
lime mixture (milk-of-lime).
i) Basic Oxygen
ii) Electric Arc Furnace
iii) Hall-Heroult cell
The principle methods of metal production: i) Basic
Furnace for iron and steel production; ii) Electric Arc
for producing steel from scrap; iii) Hall-Heroult cell for
aluminium from electrolysis. Note on each example a flux is
Source: Redrawn from Corus Group
IM prices for welding grade bauxite (FOB
China) are $470-480/tonne.
Chinese-based fluorspar producer quoted fluorspar (min. 90%
CaF2, FOB China) as $230-360/tonne over the past two
years, with current prices ranging $250-270/tonne. The producer
told IM that it expects prices in 2010 to move
up to $250-300/tonne.
Latest IM prices
for metallurgical fluorspar (Mexican, FOB Tampico) are
$140-195/tonne, while acidspar filtercake (Mexican, FOB
Tampico) are $260-290/tonne.
Lime: The average
price for quicklime amounted to $89.20/tonne in 2008, while
hydrated lime average price was $106.30/tonne.
Wollastonite: Latest IM
prices for wollastonite (Chinese, FOB, tonne acicular minus)
are $80-90/tonne for 200 mesh and $90-100/tonne for 325
Figure 1: Flux prices,
Monthly IM prices for bauxite (welding grade, FOB
China), fluorspar (acid filtercake, FOB Durban), and
wollastonite (200 mesh, acicular, FOB China), between January
2008 and December 2009. More mineral prices can be found online