Raw Materials

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Raw Materials
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Raw materials
Starting materials
Natural raw materials or industial inorganic
chemicals
Type Purity Materials Crude
materials variable shale, clay, crude bauxite,
crude kyanite Industrial minerals 95
-98 pyrophyllite, talc, feldspar, wollastonite
(refined crude materials) spodumene, glass
sand, kyanite,bauxite, zircon, rutile,
calcined kaolin, dolomite Industrial inorganic
98 - gt 99.9 clacined alumina, calcined
magnesia, chemicals fused alumina, aluminum
nitride, silicon carbide, silicon nitride,
barium carbonate, titania, calcined
titanates, calcined ferrites
K-Feldspar, kaolinite , quartz, illite
Raw materials for whiteware ceramics
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Raw materials
Mineral processing
Mineral processing steps 1.Comminution size
reduction by crushing and milling 2. Screening
size separation by sieves 3. Classification
size separation by differential gravitational
settling 4. Concentration, separation
separation of different phases in the feed -
Gravity separation - Dense medium
separation - Froth flotation - Magnetic
separation Depending on the ore, the number and
sequence of the processes will be different
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Raw materials
Kaolinite structure
Al2 Si2O5 (OH)4
T O
T O
Kaolinite "booklets", platelet diameter 4 micron
Kaolinite is a 11 dioctahedral phyllosilicate.
There are different polytypes, which have special
names i.e. dickite, nacrite etc.
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Raw materials
Kaolinite grades
Clays are categorized into six groups -Kaolin
or china clay white, claylike material composed
mainly of kaolinite industrial applications
paper coating and filling, refractories,
fiberglass and insulation, rubber, paint,
ceramics, and chemicals -Ball clay kaolin with
small amount of impurities industrial
application dinnerware, floor tile,
pottery,sanitary ware. -Fire clays kaolin with
substantial impurities (diaspore,flint) industri
al applications refractories -Bentonite clay
composed of smectite minerals, usually
montmorillonite industrial applications
drilling muds,foundry sands -Fullers earth
nonplastic clay high in magnesia, a similar to
bentonite industrial applications absorbents
-Shale laminated sedimentary rock consisting
mainly of clay minerals mud industrial
application raw material in cement and brick
manufacturing
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Raw materials
China Clay processing I
Blunging The kaolin is mixed with water and
chemical dispersants, which puts the clay
particles in suspension (slurry). De-gritting
The slurried kaolin is usually transported
through pipelines to degritting facilities
(rakes), where sand, mica and other impurities
are extracted with the help of gravity. Centrifug
ing The centrifuge separates the fine kaolin
particles from coarse particles.Fine particles,
still in the form of a slurry, move on for
further processing.
De-gritting (rake) tables
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Raw materials
China Clay processing II
Brightness enhancement Undesirable colors are
removed through one or more processes including
bleaching, magnetic separation, flocculation,
ozonation, flotation, and oxidation, which will
remove iron oxides, titanium oxides, organic, and
other undesirable materials. Delamination For
customers who want a delaminated clay product
suited for lightweight coating applications,
coarse kaolinite particles are used as starting
material. Delamination occurs as the coarse
particles of kaolin which when magnified appear
as "booklets" are broken into thin platelets by
mechanical milling.
slurry ,spray
vaccum chamber
Rotary vaccum filters
Filtering and drying Large rotary vacuum filters
remove water from the slurried kaolin. Large
gas-fired spray dryers remove and evaporate the
remaining moisture.
www.kaolin.com www.solidliquid-separation.com
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Raw materials
Bauxite
Bayer process to synthesize alumina from
bauxite Bauxite Bauxite forms most commonly in
deeply weathered rocks as a hydrated aluminum
oxide ore. In some locations, the parent material
is basalt or other volcanic rocks. Depending on
the main aluminum bearing phase, 3 types of
bauxite are distinguished gibbsitic, boehmitic
and diasporic bauxite. The composition range of
bauxites are given below.
Average composition of bauxites
Jarrahdale bauxite mine (Australia, Alcoa)
Main bauxite producing regions in the world
Australia 35, Guinea 11, China 10, Brasil 10,
Jamaica 10, India 8, others 16
http//www.alcoa.com/australia/en/info_page/mining
_homepage.asp
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Raw materials
Alumina Bayer process I
The bauxite ore is first crushed to form grains
with a diameter of less than 30 mm in hammer
crushers. It is then mixed with recycled soda
containing (NaOH) solution (s. next slide). In a
second step the bauxite-liquid mixture is ball
milled. The resulting grain size is than 315µm.
The bauxite slurry is then transferred into
digestion tanks, where the aluminum containing
phases are dissolved in the the alkaline
solution. The physicochemical parameters for the
digestion step in the Bayer process depend on the
main aluminum phase present in the bauxite. A
gibbsitic bauxite can be digested at atmospheric
pressure whereas tens of bars and more than 200C
are necessary to make the alumina contained in
diasporic bauxite soluble. The dissolution
process proceeds in two parallel steps
(1)
(2)
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Raw materials
Alumina Bayer process II
The cooled pregnant liquor flows to rows of
precipitation tanks which are seeded with
crystalline trihydrate alumina,to promote crystal
growth. Cooling and depressurizing reverses
reactions (1) and (2) above. Holding time about
3 hours.
Unsoluble residues, mainly iron and titanium
oxides, are separated from the aluminum
containing solution by gravitational settling.
The recovered mud is washed.
http//www.qal.com.au/
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Raw materials
Alumina Bayer process III
The slurry from the precipitation thanks is
filtered to extract the fines (recycled as seed
crystals). The filter cake is than calcined at
1100C (rotary kiln, or fluidized bed calciner)
resulting in sandy alumina with more than 90 of
the particles gt 45?m.
Process chart
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Raw materials
Aluminum market
Most of the refined alumina is further processed
by electrolysis to obtain aluminum. The price of
alumina is, therefore, connected to the price of
aluminum. Aluminum ingot is an internationally
produced, priced, and traded commodity whose
principal trading market is the London Metal
Exchange, or LME. In the last 4 years, the
aluminum prices went through the roof as did
all other commodity prices.
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Raw materials
Zirconium raw materials I
Zircon containing raw materials
The principal economic source of zirconium is the
zirconium silicate mineral, zircon (ZrSiO4). 
Zircon is also the primary source of all
hafnium.  Zirconium and hafnium are contained in
zircon at a ratio of about 50 to 1.  Zircon is a
coproduct or byproduct of the mining and
processing of heavy-mineral sands, which are
primarily worked for titanium minerals, ilmenite
and tin minerals.
Murray Bay heavy mineral concentrate dominated by
zircon (colorless, rounded grains) and rutile
(deep yellow grains) (Image length 20mm)
Hawks Nest, a beach sand deposit within Murray
Bay (Australia) operated by Mineral Deposits Ltd.
They extract 21,147 t of concentrate from about
20000000 t of sand. This deposit has a very low
grade (0.2 -0.3wt heavy minerals), but large
reserves. The sand is extracted by a dredge.
http//www.mineraldeposits.com.au/
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Raw materials
Zirconium raw materials II
Raw materials extraction
The heavy mineral bearing sands are extracted
within artifical ponds (above) by dredgers (left)
and pumped to the separation and concentration
plant.
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Raw materials
Zirconium raw materials III
Separation of zircon from the heavy sand raw
material
The main separation method for heavy mineral sand
is based on the difference in gravity
Mineral sand slurry moving down the spiral
gravity separator with increased concentration of
the heavy minerals in the center of the spiral.
http//www.outokumpu.com http//www.tiomin.com/
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Raw materials
Zirconium production
World Mine Production, Reserves, and Reserve
Base World primary hafnium production statistics
are notavailable. Hafnium occurs with zirconium
in the minerals zircon and baddeleyite.
Zirconium
Mine production
Reserves Reserve base
(thousand metric tons)
(million metric tons, ZrO2)
2002 2003 United States 100
100 3.4 5.3 Australia 408 40
9.1 30.0 Brazil 21 30 2.2 4.6 China 15
15 0.5 3.7 India 19 20 3.4 3.8 South
Africa 224 280 14.0 14.0 Ukraine
34 34 4.0 6.0 Other countries 9 10 0.9
4.1 World total (rounded) 830 890 38.0 72.0
http//minerals.usgs.gov/minerals/
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Raw materials
Zirconium extraction I
Chemical extraction of zirconia from zircon ore

• There are two methods to make zirconia from the
  zirconyl chloride thermal decomposition and
  precipitation. The precipitation method, however,
  gives the better end-product
• ZrOCl2 8H2O in solution
• NH4OH
• Precipitated intermediate Zr(OH) 4
• Wash
• Cl--free precipitate, wet Zr(OH) 4
• Freeze Drying (Liquid N2)
• Dried powdered Zr(OH)4
• Calcination
• Zirconia Powder ZrO2

• Zirconia is usually produced from zircon, ZrSiO4.
  The first step is to convert zircon to zirconyl
  chloride. It can be done by
• Zircon (ZrSiO4) NaOH
• Melting
• Na2ZrO3
• HCl
• ZrOCl2 8H2O

http//www.zrchem.com/
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Raw materials
Zirconium extraction II
Chemical extraction of zirconium from zirconia
In industry, reduction of ores with carbon is not
a useful option as intractable carbides are
produced. As for titanium, the Kroll method is
used for zirconium and involves the action of
chlorine and carbon upon baddeleyite (ZrO2). The
resultant titanium tetrachloride, ZrCl4, is
separated from the iron trichloride, FeCl3, by
fractional distillation. Finally ZrCl4 is reduced
to metallic zirconium by reduction with
magnesium, Mg. Air is excluded so as to prevent
contamination of the product with oxygen or
nitrogen. ZrO2 2Cl2 2C (900C) ZrCl4
2CO ZrCl4 2Mg (1100C) 2MgCl2 Zr Excess
magnesium and magnesium dichloride is removed
from the product by treatment with water and
hydrochloric acid to leave a zirconium "sponge".
This can be melted under helium by electrical
heating.
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Raw materials
Zirconium market
World market price evolution of zirconium

• The zircon ore price more than doubled in the
  last 12 years
• 319/ton
• 2000 396/ton
• 2004 477/ton
• 2005 661/ton
• 2006 791/ton
• There is a 1000fold increase between the ore
  price and the final zirconium powder price!
  Zirconium oxide (98) traded for 3000/ton in
  2005.