INDUSTRIAL MINERAL CONCENTRATION TECNOLOGIES

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INDUSTRIAL MINERAL CONCENTRATION TECNOLOGIES

• Prof.Dr. Muammer KAYA
• Osmangazi University
• Eskisehir-TURKEY
• 2007

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From raw material
To Final Product
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Principles of Flotation
Flotation concentration method utilizes the differences in physico chemical surface properties of particles. Hydrophobic (water repellent) particles float with air bubbles to form a froth. Wetted hydrophilic particles sink. Hydrophobicity increases with the contact angle btw particles and bubbles. Chemical reagents are used in flotation. Flotation is a selective separation process. Flotation is the most important and versatile mineral processing technique used in mining industry.
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APPLICATION OF FLOTATION

• Flotation can be successfully applied to both
  metallic and industrial minerals given below for
  removing impurities and improving quality
• Apatite/Phosphate, Barite, Calcite, Dolomite,
  Feldspar, Fluorspar, Graphite, Iron Ore, Kyanite,
  Magnesite, Monazite, Potash, Pyrochlore,
  Quartz/Silica Sand, Scheelite etc.

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MECHANICAL FLOTATION MACHINE
Froth flotation is achieved when particles are
separated based on their surface potential.
Hydrophobic particles are recovered to the froth,
whereas hydrophilic particles are discharged with
the tailings stream.
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PHOSPHATE MINERALS

• Phosphate minerals are those minerals that
  contain the tetrahedrally coordinated phosphate
  (PO43-) anion along with the freely substituting
  arsenate (AsO43-) and vanadate (VO43-). Chlorine
  (Cl-), fluorine (F-), and hydroxide (OH-) anions
  also fit into the crystal structure.
• The phosphate class of minerals is a large and
  diverse group, however, only a few species are
  relatively common.
• Examples include
• triphylite Li(Fe,Mn)PO4
• monazite (Ce,La,Y,Th)PO4
• Apatite group Ca5(PO4)3(F,Cl,OH)
• hydroxylapatite Ca5(PO4)3OH
• fluorapatite Ca5(PO4)3F
• chlorapatite Ca5(PO4)3Cl
• pyromorphite Pb5(PO4)3Cl
• vanadinite Pb5(VO4)3Cl
• erythrite Co3(AsO4)28H2O
• amblygonite LiAlPO4F
• lazulite (Mg,Fe)Al2(PO4)2(OH)2
• wavellite Al3(PO4)2(OH)35H2O
• turquoise CuAl6(PO4)4(OH)85H2O
• autunite Ca(UO2)2(PO4)210-12H2O
• carnotite K2(UO2)2(VO4)23H2O

PO43- anion
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DEPOSITS

• Rock phosphate can also be found on USA, Egypt,
  Israel, Morocco, Navassa Island, Tunisia, Togo,
  S. Arabia and Jordan have large phosphate mining
  industries as well.

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USE OF PHOSPHATE

• Phosphates were once commonly used in laundry
  detergent in the form trisodium phosphate (TSP),
  but, because of algae boom-bust cycles tied to
  emission of phosphates into watersheds, phosphate
  detergent sale or usage is restricted in some
  areas.
• In agriculture, phosphate is one of the three
  primary plant nutrients, and it is a component of
  fertilizers. Rock phosphate is quarried from
  phosphate beds in sedimentary rocks. In former
  times, it was simply crushed and used as is, but
  the crude form is now used only in organic
  farming. Normally, it is chemically treated to
  make superphosphate, triple superphosphate, or
  ammonium phosphates, which have higher
  concentration of phosphate and are also more
  soluble, therefore more quickly usable by plants.
• Fertilizer grades have three numbers the first
  is the available nitrogen, the second is the
  available phosphate (expressed on a P2O5 basis),
  and the third is the available potash (expressed
  on a K2O basis). Thus a 10-10-10 fertilizer would
  contain ten percent of each, with the remainder
  being filler.
• Surface runoff of phosphates from
  excessively-fertilized farmland can be a cause of
  phosphate pollution, leading to eutrophication
  (nutrient enrichment), algal bloom, and
  consequent oxygen deficit. This can lead to
  anoxia for fish and other aquatic organisms in
  the same manner as phosphate-based detergents.
• Phosphate compounds are occasionally added to the
  public drinking water supply to counter
  plumbosolvency.
• The food industry uses phosphates to perform
  several different functions. For example, in meat
  products, it solubilizes the protein. This
  improves its water-holding ability and increases
  its moistness and succulence. In baked products,
  such as cookies and crackers, phosphate compounds
  can act as part of the leavening system when it
  reacts with an alkalai, usually sodium
  bicarbonate (baking soda).
• Phosphate minerals are often used for control of
  rust and prevention of corrosion on ferrous
  materials, applied with electrochemical
  conversion coatings

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PHOSPHATE FLOTATION

• Collophane, the principal phosphate mineral
  occuring in the phospate deposits of the
  Southeastern US, floats readily with crude fatty
  acids and soaps, fuel oil and soda ash, caustic
  soda or amonia.
• Double flotation method is used in US Florida
  plants by using both fatty acid and amine types
  of collectors.
• Single flotation is employed at N.Africa and
  Middle Eastern phosphate operations by using
  either a fatty acid or an amine type of
  collector.
• Cytecs Aero 727, 727J and 728 promoters have
  been successfully used where only fatty acid
  float approach is practiced.
• Cytecs Aero 8651 fatty amine promer is utilized
  in operations running an amine float.
• In the reverse flotation, Cytec Acco-Phos 950
  depressant (20-100 g/t) minimizes phosphate loses
  into the silica froth product using amine
  collectors.
• In the treatment of sedimentary pebble
  phosphates, Aero 845 can be used in conjuction
  with fatty acids.

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US DOUBLE PHOSPHATE FLOTATION
-
FEED
Slimes (-10 ?)
Desliming (Hydrocyclones)

conditioner
Phosphate-Silica Sep. Flot
70S
T
F
Silica (final tails)
Rougher fl.
pH9-9.5 (sodaash/NaOH) Crude fatty oil Fuel-oil
C
Conditioning with H2SO4washing to remove reagents
Silica Removal Reverse Flot.
Cleaner fl.
Phosphate Conc.
pH6.5-7 Fatty/ether amine
conditioner
Silica (gangue)
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LIME STONE/CALCITE

• Limestone is a sedimentary rock composed largely
  of the mineral calcite (calcium carbonate
  CaCO3). l
• Limestone often contains variable amounts of
  silica in the form of chert or flint, as well as
  varying amounts of clay, silt and sand as
  disseminations, nodules, or layers within the
  rock.

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USES OF LIMESTONE
Iron impregnations in limestone

• The manufacture of quicklime (calcium oxide) and
  slaked lime (calcium hydroxide)
• Cement and mortar
• Pulverized limestone is used as a soil
  conditioner to neutralize acidic soil conditions
  
• Crushed for use as aggregatethe solid base for
  many roads
• Limestone is especially popular in architecture
  as building stone/ material
• Geological formations of limestone are among the
  best petroleum reservoirs
• As a reagent in desulfurizations
• Glass making
• Toothpaste
• Added to bread as a source of calcium

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LIME STONE/CALCITE (CaCO3) FLOTATION

• Natural limestone/calcite deposits contain
  various types of silicates and graphite
  impurities.
• For applications like paper fillers the calcite
  has to have a low grade of abrasive silicates as
  well as a high brightness.
• Even very low amounts of graphite is detrimental
  to the brightness.
• Beneficiation of limestone by froth flotation
  utilizing Aero 845 promoter can be simple
  process.
• Limestone is floated with/without prior desliming
  with the emulsion of Aero 845 and number 5 fuel
  oil.
• Silicates can be depressed by Na2SiO3 (500-1000
  g/t).
• Compared to fatty acids, Aero 845 promoter (Pet.
  Sulphonate type anionic collector) offer the
  advantage of better product control at a saving
  in total collector usage.

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Sparingly soluble salts flot.
Complete flot.
R100
pH6- 9
R0
No flot.
Mole/l
Calcite flot. recovery depends on NaOl
concentration and HC chain length of the
collector. In general, when the collector length
of the HC chain is increased, the concentration
of collector necessary for flotation is reduced.
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GRAPHITE CONCENTRATION TECHNOLOGY

• Graphite is one of the allotropes of carbon.
  Unlike diamond, graphite is an electrical
  conductor.
• Graphite holds the distinction of being the most
  stable form of solid carbon ever discovered.
• It may be considered the highest grade of coal,
  just above anthracite and alternatively called
  meta-anthracite, although it is not normally used
  as fuel because it is hard to ignite.

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CLASSIFICATION OF GRAPHITE

• There are three principal types of natural
  graphite, each occurring in different types of
  ore deposit
• (1) Crystalline flake graphite (53) occurs as
  isolated, flat, plate-like particles with
  hexagonal edges if unbroken and when broken the
  edges can be irregular or angular
  (Madagascar-open pit, 410-950 /t)
• (2) Amorphous graphite occurs as fine particles
  (Mexico-Underground mines, 240-260 /t)
• (3) Lump graphite (also called vein graphite)
  occurs in fissure veins or fractures and appears
  as massive platy intergrowths of fibrous or
  acicular crystalline aggregates, and is probably
  hydrothermal in origin (Sri Lanka-Underground
  mines).

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USE AREAS OF GRAPHITE
MAJOR USE AREAS REFRACTORIES (High temperature applications- Melting Point 3927C) Coarse flakes Graphite crucibles Carbon-magnesite/alumina bricks (95-99 C) Monolitics (gunning and ramming mixtures) Continuous casting ware (nozzles, troughs)
STEEL MAKING Amorphous or fine flaked Carbon rising in molten steel Lubricating dies during hot metal extrution
EXPANDED GRAPHITE Flakes Made from flake graphite using chromic acid sulphuric acids to produce foils Can be used to insulate molten metal in ladle, fuel cells and heat sinks for laptop computer
MINOR USE AREAS BRIKE LINING/SHOES FOR HEAVY TRUCKS FOUNDRY FACING and LUBRICANTS PENCIL LEAD Zn-C BATTERIES ELECTRIC MOTOR BRUSHES GRAPHITE(CARBON) FIBERS/NANOTUBES Made from amourphous or fine flakes Substitute for asbestos Amourphous or fine flakes are used High temp. dry lubricant Powder graphiteclay Powdered fine flaked graphite Powder graphite Reinforced/antistatic/conductive plastics/ concreates/rubbers
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IMPURITIES and PROPERTIES

• Minerals associated with graphite include quartz,
  calcite, micas, iron meteorites, and tourmalines.
• In 2005, world natural graphite production was
  1.05 million t and China was the top producer of
  graphite with about 80 world share followed by
  India and Brazil.
• Graphite has various characteristics. Thin flakes
  are flexible but inelastic, the mineral can leave
  black marks on hands and paper, it is
  diamagnetic, adsorbant, conducts electricity, and
  displays superlubricity. Its best field
  indicators are softness, luster, density and
  streak.

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GRAPHITE BENEFICIATION METHODS

• Vary from a complex flotation at Europe and USA
  mills to simply hand sorting and screening
  with/without milling of high-grade ores in Sri
  Lanka.
• Certain soft flake-type graphite ores, (like in
  Madagascar) need no primary crushing and
  grinding.
• GRAPHITE MILLING ONLY
• Graphite can be ground to a fine powder for use
  as a slurry in oil drilling in zirconium
  silicate, sodium silicate and isopropyl alcohol
  coatings for foundry molds and for calcined
  petroleum coke, which is used as a carbon raiser
  in the steel industry.
• Rough graphite is typically ground and packaged
  at a graphite mill. Since the Work Index of
  graphite is high, power consumption during
  grinding will be high.
• Environmental impacts from graphite mills consist
  of air pollution including fine particulate
  exposure of workers and also soil contamination
  from powder spillages leading to heavy metals
  contaminations of soil. Dust masks are normally
  worn by workers during the production process to
  avoid worker exposure to the fine airborne
  graphite and zircon silicate.

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GRAPHITE FLOTATION

• Since graphite is naturally hydrophobic (i.e.
  floats easily), impurites can easily be removed
  by direct flotation process.
• Flotation process can be applied to low carbon
  and high silica containing graphite ores.
• 1. DESLIMING STEP for removing clay minerals,
• 2. ROUGHER FLOTATION to produce a concentrate
  with 60-70 C.
• 3. REGRINDINGCLEANER FLOTATION to reach 85 C.
• 4. SCREENING to produce 75-95C.
• - 0.5 mm graphite can be floated using
  fuel-oil/kerosene as the promoter and
  pine-oil/F-77/MIBC as frother at natural pH.
  Na2SiO3/HF can be used as silicate depressant.

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IRON ORES
Brazillian hematite

• Iron ores are rocks and minerals from which
  metallic iron can be economically extracted. The
  ores are usually rich in iron oxides and vary in
  color from dark grey to rusty red. The iron
  itself is usually found in the form of magnetite
  (Fe3O4), hematite (Fe2O3), limonite or siderite.
  Hematite ores containing 66 Fe can be fed
  directly into iron making blast furnaces. Iron
  ore is the raw material used to make pig iron,
  which is one of the main raw materials to make
  steel. 98 of the mined iron ore is used to make
  steel.

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Consumption and economics

• Iron is the world's most commonly used metal. It
  is used primarily in structural engineering
  applications, automobiles, and general industrial
  applications (machinery).
• Iron-rich rocks are common worldwide, but
  ore-grade commercial mining operations are
  dominated by few countries.
• World production averages one billion metric tons
  of raw ore annually. The world's largest producer
  of iron ore is the Brazilian mining corporation
  CVRD, followed by Australian company BHP Billiton
  and the Anglo-Australian Rio Tinto Group.
• China, Japan and S. Korea are currently the
  largest consumer of iron ore/steel. which
  translates to be the world's largest steel
  producing country.

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LOW GRADE IRON ORE BENEFICIATION

• Due to the high density of hematite (5.3)
  relative to silicates (2.7), beneficiation
  usually involves a combination of crushing and
  milling as well as heavy liquid separation.
• This is achieved by passing the finely crushed
  ore over a bath of solution containing bentonite
  or other agent which increases the density of the
  solution. When the density of the solution is
  properly calibrated, the hematite will sink and
  the silicate mineral fragments will float and can
  be removed.

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FLOTATION OF IRON ORE

• Due to increased demand for iron ore products low
  in silica and phosphorous plus increased world
  competition, quality considerations have become
  more and more important.
• Dephosphorization of iron ores is necessary.
• The results obtained in plant operations vary,
  depending on ore type and the process.
• Direct flotation of iron ores was practiced for
  many years using Aero899R promoter (1-2 kg/t)
  along with number 5 fuel oil at pH 3-5 adjusted
  by H2SO4 following high solids conditioning.
• Reverse flotation of silica with etheramine
  collectorsfrother (Aerofroth or Oreprep) has
  been the traditional route for many years to
  produce a final iron ore concentrate. While
  removing silica from the iron ore, fine iron
  particles should not excessively lost.

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FINE IRON ORE PELLETS
Iron ore fines and flotation concentrates should
be pelletized with bentonite before being charged
into the blast furnace to produce pig-iron which
is used in steel production.
Iron pellets
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HEAVY MINERAL SANDS

• Sand is a naturally occurring granular material
  comprised of finely divided rock and mineral
  particles.
• Sand is transported by wind and water and
  deposited in the form of beaches, dunes, sand
  spits, sand bars (placer deposits) etc.
• The most common constituents of sands are silica
  (SiO2), usually in the form of quartz, iron
  oxides, zircon, rutile, ilmenite, monazite,
  garnet.
• Heavy mineral sands are a class of ore deposit
  which is an important source of zirconium,
  titanium, thorium, tungsten, rare earth elements,
  the industrial minerals diamond, sapphire,
  garnet, and occasionally precious metals or
  gemstones.

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Grade and Tonnage Distribution

• The grade of a typical heavy mineral sand ore
  deposit is usually low. The lowest cut-off grades
  of heavy minerals, as a total heavy mineral (THM)
  concentrate from the bulk sand, in most ore
  deposits of this type is around 1 heavy
  minerals, although several are higher grade.
• Of this total heavy mineral concentrate (THM),
  the components are typically
• Zircon, from 1 of THM to upwards of 50 of THM,
• Ilmenite, generally of 10 to 60 of THM
• Rutile, from 5 to 25 of THM
• Leucoxene, from 1 to 10 of THM
• Trash minerals, typically magnetite, garnet and
  chromite which usually account for the remaining
  bulk of the THM content
• Slimes, typically minerals as above and heavy
  clay minerals, too fine to be economically
  extracted.
• Modern open-pit mining practises tend to favor
  dry mining rather than dredging operations, due
  to the advent of electrostatic mineral separation
  processes.

Black sand conc.
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USE OF SAND

• Sand is often a principal component of concrete.
• Molding sand, also known as foundry sand, is
  moistened or oiled and then shaped into molds for
  sand casting. This type of sand must be able to
  withstand high temperatures and pressure, allow
  gases to escape, have a uniform, small grain size
  and be non-reactive with metals.
• It is the principal component in glass
  manufacturing.
• Graded sand is used as an abrasive in
  sandblasting and is also used in media filters
  for filtering water.
• Brick manufacturing plants use sand as an
  additive with a mixture of clay and other
  materials for manufacturing bricks.
• Sand is sometimes mixed with paint to create a
  textured finish for walls and ceilings or a
  non-slip floor surface.
• Sandy soils are ideal for certain crops such as
  watermelons, peaches, and peanuts and are often
  preferred for intensive dairy farming because of
  their excellent drainage characteristics.
• Sand is used in landscaping, it is added to make
  small hills and slopes (for example, constructing
  golf courses).
• Beach nourishment - transportation to popular
  beaches where seasonal tides or artificial
  changes to the shoreline cause the original sand
  to flow out to sea.2
• Sandbags are used for protection against floods
  and gun fire. They can be easily transported when
  empty, then filled with local sand.
• Sand castle building is a popular activity. There
  are competitive sand castle building competitions
  (See sand art and play).
• Sand animation is a type of performance art and a
  technique for creating animated films.
• Aquaria are often lined with sand instead of
  gravel. This is a low cost alternative which some
  believe is better than gravel.
• Railroads use sand to improve the traction of
  wheels on the rails.

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GLASS SANDS BENEFICIATION

• CONCENTRATION OF HEAVY MINERALS
• Gravity (sluices, spirals, shaking tables,
  Reichert cones), magnetic (low/high intensity
  dry/wet) and high tension separation methods can
  be used together to treat/upgrade the heavy
  content of the beach sands.
• GLASS SAND FLOTATION FOR IRON IMPURITY REMOVAL
• After removal of the Fe-bearing impurities, some
  plants separate feldspar from quartz by floating
  feldspar with amines at pH 3 using HF.
• Some glass sand operations, naturally-occuring
  organic colloids may make a fatty acid float of
  iron-bearing minerals preferable.
• After desliming, the pulp is conditioned at high
  solids with Aero 700 series promoters at pH 8-9
  adjusted with soda ash or caustic soda. Fuel oil
  may be added to the flotation circuit for froth
  control.

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GARNET X3Y2(SiO4)3
crystal
Molecular model

• Garnet is a group of minerals that can be used as
  gemstones and abrasives (Mohs hardness 6-7.5).
  Garnets are most often seen in red, but are
  available in a wide variety of colors. Spec. Gr.
  is btw 3.1-4.3.
• Major varieties X Y (SiO4)3 USE
  AREA
• Pyrope Mg3Al2Si3O12
• Almandine Fe3Al2Si3O12 abrasive
• Spessartite Mn3Al2Si3O12 gemstone
• Andradite Ca3Fe2Si3O12
• Grossular Ca3Al2Si3O12
• Uvarovite Ca3Cr2Si3O12 gemstone
• Garnet speciess light transmission properties
  can range from the gemstone-quality transparent
  specimens to the opaque varieties used for
  industrial purposes as abrasives.

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Uses Concentration of GARNETS

• Pure crystals of garnet are used as gemstones.
  Garnet sand is a good abrasive, and a common
  replacement for silica sand in sand blasting.
  Mixed with very high pressure water, garnet is
  used to cut steel and other materials in water
  jets. Garnet sand is also used for water
  filtration media.
• Garnets can be concentrated from sands by
  gravity electrostaticmagnetic separation
  methods along with monazite.

Pendant in uvarovite, a rare bright-green garnet.
Almandine in gneissic rock, hardness 6-7.5,
abrasive
Spessartine (the yellow mineral) gemstone
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OCCURENCE OF KAOLIN (Al2O3.2SiO2.2H2O)

• Feldspar
• Mica
• Granite
• Syanite
• Porphyr
• Quartz
• Rutile
• Ilmenite

Primary Deposits 20-30 Kaolin Cormwall/UK
alteration
KAOLIN
Sedimantary Deposits 95 Kaolin Georgia/USA
No-decomposition
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LIBERATION OF KAOLIN

• Liberation size for KAOLIN 4-6 ?m.
• Liberation size for FELDSPAR 200-300 ?m.
• Liberation size for QUARTZ 700 ?m.
• KAOLIN CAN EASILY BE CONCENTRATED BY
  CLASSIFICATION ACCORDING TO PARTICLE SIZE USING
  SCREENS AND HYDROCYCLONES
• Before concentration
• ? For soft kaolins?Attrition scrubbing for
  dispersing clays
• ? For hard kaolins?crushing/grinding are
  required.
• (Due to remaining fine silica product,
  quality is low)
• CLASSIFICATION CONCENTRATION
• ? DRY (Crushingdry grindingair classification)
• (requires selective mining operation)
• ? WET (Magnetic separationflotationhydrocyclones
  )
• (complex flowsheet, but product quality is very
  high)

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• The production process includes disintegration
  and classification, hydrocycloning, thickening,
  filter-pressing and drying. Product range kaolin
  for ceramic, kaolin for paper, glass silica sand,
  dry and wet classified silica sand, ground
  kaolin, chamotte.

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Process

• The extraction plant is situated adjacent to the
  quarrying operation to enable the waste to be
  returned to backfill.
• Crude kaolin from the quarry is first made into a
  slurry with water. This slurry passes through a
  series of washing and classification steps in
  order to remove the quartz and mica impurities.
  This results in a pure kaolin product which is
  completely devoid of free silica.
• The kaolin is filtered in filter presses and the
  filter cake is pressed into pellet form prior to
  drying in gas-fired dryers. The final kaolin
  pellets contain 10 moisture on average. These
  are packaged and despatched to customers in the
  ceramic, paint, paper and other industries.
• A dry powder product is also produced for those
  industries that cannot tolerate moisture, such as
  the rubber, plastic and pesticide industries. The
  dry powder is produced by passing the kaolin
  pellets through an attritor and classifier with
  simultaneous drying with hot air.
• Water from the drying process is recovered and
  recycled to the extraction plant through a return
  water pipeline.

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MAJOR IMPURITIES(Kaolin is used in fine size
range. Flotation efficiency diminishes with the
size of particles. Kaolin is used as a white
pigment thus colored impurities must be removed).

• Anatase (TiO2) Fine sized anatase contains
  considerable amount Fe and gives brownish tint to
  the clays. This mineral may be removed by fatty
  acid flotation after activating with divalent
  cations to produce coating grade (bright) clays.
  Yoon et al. (2003) found that alkyl hydroxametes
  were much more effective than fatty acids in
  floating colored anatase impurity from clays. No
  activation is necessary and retention times in
  flotation are shorter than fatty acids.
• Iron oxides

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KAOLIN FLOTATION

• CARRIER FLOTATION and CARRIERLESS FLOTATION can
  be used.
• Collector Fatty acids.

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Sparingly Soluble Salts
NaOl - sodium oleate, DDA-dodecylamine, SDS,-
sodium dedecyl sulfite
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Class 5. Sparingly soluble salts
Flotation with potassium octylohydroxymate
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Class 4. Oxides and hydroxides
Amine flotation of quartz
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Class 6. Soluble salts
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POTASH

• Potash is the most important source of potassium
  in fertilizers.
• Flotation is one of the major methods to upgrade
  the potash.
• Normally fatty acids are used as collectors for
  flotation. However, this type of collectors is
  not always suitable for the treatment of complex
  phosphate ores when calcite and dolomite are
  present.
• Calcite and dolomite tent to co-float with
  phosphate giving low concentrate grades.
• Potash can be separated from halite by reverse
  flotation.

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