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ME551/GEO551 Geology of Industrial Minerals Spring 2007

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Title: ME551/GEO551 Geology of Industrial Minerals Spring 2007


1
ME551/GEO551 Geology of Industrial Minerals
Spring 2007
  • Commodities, Part 2
  • Clays, Diamonds, Diatomite, Fluorite, Garnet,
    Graphite

2
Reminders
  • What is trap rock?
  • Field trip to potash mines next week
  • Monday leave at 9 AM
  • Tues tour and return to Socorro
  • Hotel
  • Buckets for collecting
  • Term Projects?
  • March 20 I will not be teachingJim Barker
  • Any questions on the midterm?
  • Due March 9

3
Clays
  • BentoniteJeremy

4
ClaysIntroduction
  • Stone age
  • Types
  • ball clay (primarily of kaolinite with illite,
    chlorite, smectite minerals, quartz)
  • bentonite (smectite with feldspars, biotite,
    quartz)
  • common clay (illite and chlorite, others)
  • fire clay (kaolinite, halloysite, diaspore)
  • fullers earth (attapulgite, montmorillonite)
  • kaolin

5
Types
  • layer silicates
  • layers of tetrahedral and octahedral sheets
  • Kaolinite, smectite, illite, chlorite,
    vermiculite
  • the metal oxides and hydroxides and oxy-oxides
  • gibsite
  • amorphous and allophanes
  • structurally disordered aluminosilicates
  • Allophane, Imogolite

6
Claysdefinition
  • particle size of less than 2 micrometers
  • family of minerals
  • rock term

7
Claysproperties
  • chemical composition
  • layered structure
  • size
  • great affinity for water (double in thickness
    when wet)
  • soak up ions, release the ions later when
    conditions change

8
Claysproperties
  • Color
  • plasticity
  • mineral composition
  • absorption qualities
  • firing characteristics
  • clarification properties

9
Propertiescharge sources
Two main sources of charge in clay minerals are isomorphous substitution and pH-dependent charges.
  Charge development of on silicate clays is mainly due to isomorphous substitution. This is the substitution of one element for another in ionic crystals with out change of the structure. It takes place during crystallization and is not subject to change afterwards. It takes places only between ions differing by less than about 10 to 15 in crystal radii.. In tetrahedral coordination, Al3 for Si4 and in octahedral coordination Mg2, Fe2, Fe3 for Al3. Charges developed as a result of isomorphous substitution are permanent and not pH-dependent.
  In allophanes, some silicate clays e.g. kaolinite, and the metal oxides the main source of charge are termed pH -dependent charges because these charges depend on the pH of the soil. pH depend charges are variable and may either be positive or negative depending on the pH of the soil. In the metal oxides acid soils tend to develop positive charges because of the protonation of the oh ggoud on the oxide surfaces.
  • Two main sources of charge in clay minerals are
    isomorphous substitution and pH-dependent
    charges.

http//jan.ucc.nau.edu/doetqp/courses/env320/lec12
/Lec12.html
10
Charge properties
  • Charge development of on silicate clays is mainly
    due to isomorphous substitution.
  • This is the substitution of one element for
    another in ionic crystals with out change of the
    structure.
  • It takes place during crystallization and is not
    subject to change afterwards.
  • It takes places only between ions differing by
    less than about 10 to 15 in crystal radii.
  • In tetrahedral coordination, Al3 for Si4 and in
    octahedral coordination Mg2, Fe2, Fe3 for
    Al3.
  • Charges developed as a result of isomorphous
    substitution are permanent and not pH-dependent.

11
Charge properties
  • In allophanes, some silicate clays e.g.
    kaolinite, and the metal oxides the main source
    of charge are termed pH -dependent charges
    because these charges depend on the pH of the
    soil.
  • pH depend charges are variable and may either be
    positive or negative depending on the pH of the
    soil.
  • In the metal oxides acid soils tend to develop
    positive charges because of the protonation of
    the oh ggoud on the oxide surfaces.

12
Clayuses
  • Ceramics
  • fillers and extenders
  • construction (hydraulic cement, structural clay
    products, aggregates)
  • drilling mud
  • fiberglass
  • Iron Ore Pelletizing
  • paper
  • carrier to mix paint and color pigment

13
Ball clayuses
  • Burn to a light color and accepts glaze, plastic
  • 35 floor and wall tile
  • 22 sanitaryware
  • 43 other uses

14
Bentoniteuses
  • Clay consisting of smectites

15
Common clayuses
  • 56 brick
  • 20 cement
  • 16 lightweight aggregate
  • 8 other uses (fillers and extenders)

16
Fire clayuses
  • 73 refractories
  • 27 other uses

17
Fullers earthuses
  • mineral substance characterized by the property
    of absorbing basic colors and removing them from
    oils
  • fulling of wool to remove oil and grease
  • 75 absorbent uses
  • 25 other uses

18
Kaolinuses
  • Near white containing kaolinite
  • 55 paper
  • 7 refractories
  • 38 other uses

19
Kaolinuses
  • mildew-resistant latex paints
  • vinyl wire insulation
  • printing inks
  • Cosmetics
  • rubber tires
  • fiberglass and nylon
  • auto and truck body components
  • production of medicines
  • ceramics
  • catalysts for petroleum refining
  • extenders for fertilizers, pesticides, and
    herbicides

20
Kaolin
21
Clayssubstitutions
  • Limited substitutions possible
  • calcium carbonate
  • talc

22
Claysproduction
  • ball clay
  • common clay various
  • fire clay
  • fullers earth U.S., Germany
  • kaolin U.S., Uzbekistan, Czech Republic, United
    Kingdom, Brazil

23
Claysgeology
  • soil horizons
  • continental and marine sediments
  • geothermal fields
  • volcanic deposits
  • weathering rock formations
  • coal beds

24
Bricksprocessing
  • Common clay used to make bricks
  • formed or shaped either by extrusion
  • involves forming a column of clay by pushing the
    material through a die at high pressure.
  • then cut into bricks (known as 'wirecut')
  • drainage pipes and clay roof tiles made similar
    process

25
Bricksprocessing
  • or the 'soft-mud' process
  • individual bricks are formed in a sand-lined
    mould from a clay with a relatively high moisture
    content (known as 'stock' bricks)
  • dried prior to firing
  • fired using natural gas in a linear kiln known as
    a 'tunnel kiln
  • 10501100C

26
Environmental considerationsclay
  • Open pits
  • organic emissions (EPA developing standards,
    MACT)
  • impoundment of slimes
  • dust control

27
Colin C. Harvey, 1999
28
Diamonds
29
Diamonds
  • Greek adamas meaning invincible
  • Used in India 2,500 yrs ago

30
Diamondsintroduction
  • clarity, color, shape, size is used as
    industrial-grade diamond (nongem)

http//www.brysonburke.com/diamonds_find_the_sourc
e.html
31
Diamondsproperties
  • Hardest substance known
  • highest thermal conductivity
  • chemical stability
  • optical properties
  • refract light

atomic connectivity of the carbon atoms gives
the gem its hardness
32
Diamondsproduction
33
Diamondsuses
  • Middle Ages--healing powers
  • Grinding
  • drilling
  • cutting
  • polishing
  • abrasive
  • wear- and corrosion-resistant coatings,
  • special lenses
  • heat sinks in electrical circuits
  • wire drawing

34
Diamondssubstitutions
  • cubic boron nitride
  • silicon nitride
  • but diamond is more than twice as hard
  • synthetic diamonds (US)

35
Diamondsgeology
  • Kimberlites
  • lamprorites
  • alluvial (placer) deposits for these rocks
  • molten rock from 75 to 120 miles below the
    earth's surface 40 kbar and 900 C

36
The slightly misshapen octahedral shape of this
rough diamond crystal in matrix is typical of the
mineral. Its lustrous faces also indicate that
this crystal is from a primary deposit
http//en.wikipedia.org/wiki/Diamond
37
Schematic diagram of a volcanic pipe
http//en.wikipedia.org/wiki/Diamond
38
Indicator minerals
  • ilmenite
  • titanium and magnesium rich chromite
  • chrome diopside
  • magnesium rich olivine
  • pyrope garnets
  • eclogitic garnets

39
Carat
  • carat weight measures the mass of a diamond
  • One carat is defined as a fifth of a gram
  • 200 milligrams
  • approximately 0.007 ounce
  • point unitequal to one one-hundredth of a carat
    (0.01 carat, or 2 mg)

40
Price
41
Mining
Alluvial mining by traditional methods
continues, as seen here in Sierra Leone.
42
Mining
43
Diamondsprocessing
  • Crush
  • scrubbers and degritting and sanding
    sections remove fine waste
    material for disposal
  • Heavy-medium separation or grease belts
  • X-ray fluorescence sorters are used to extract
    the diamonds

44
Diatomite
45
Diatomiteintroduction
  • made of plant fossils shaped like soda straws
  • silica
  • looks like chalk (CaCO3)
  • diatomaceous earth

46
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47
Diatomite
http//www.rockdetective.org/f...
48
Diatomite
http//www.maidenwell.com/
49
Chemical composition
  • 86 silica
  • 5 sodium
  • 3 magnesium
  • 2 iron

50
Diatomiteproperties
  • Light weight (hollow fossil shells)
  • does not conduct heat

51
Diatomiteuses
  • Once used in dynamite
  • insulate steam pipes
  • filtration aid (swimming pools)
  • mild abrasive
  • mechanical insecticide (physico-sorptive
    properties)
  • absorbent for liquids
  • Cat litter
  • activator in blood clotting studies
  • thermal insulator
  • plants

52
Diatomitesubstitutions
  • Expanded perlite
  • silica sand
  • talc
  • ground silica sand,
  • ground mica
  • clay
  • exfoliated vermiculite
  • Perlite
  • vermiculite
  • ground limestone
  • various clays
  • special brick
  • mineral wool
  • expanded perlite

53
Diatomiteproduction
54
Diatomitegeology
  • Saltwater
  • contains a high crystalline silica content
  • Fresh water lake
  • dry lakebeds and is characteristically low in
    crystalline silica content

55
Diatomaceous earth
http//www.minerals.epcorp.com..
56
Dredging is one mining method
http//www.hi.is/HI/Stofn/Myva...
57
Safety
  • drying of the hands, if handled without gloves
  • highly crystalline form of silica, resulting in
    sharp edges
  • dangerous to breathe and a dust mask is
    recommended when working with it
  • silicosis

58
Fluorite
59
Fluorite
  • Latin fluo, meaning flow

60
Fluoriteintroduction
  • CaF2, Calcium Fluoride
  • halide
  • variable color
  • Luster is vitreous.
  • transparent to translucent.
  • Cleavage is perfect in 4 directions forming
    octahedrons.
  • Hardness is 4
  • Fracture is irregular and brittle.
  • Specific Gravity is 3.1 (heavy)

61
Fluoriteproperties
  • fluorospar
  • ability as a flux
  • ore of F

62
Fluoriteuses
  • flux in steel and aluminum processing
  • in the preparation of glasses and enamels
  • manufacture of hydrofluoric acid
  • for carved ornamental objects
  • fluorinated water
  • gemstone

63
Fluorite
http//mineral.galleries.com/minerals/halides/fluo
rite/fluorite.htm
64
Fluoritesubstitutions
  • Olivine
  • dolomitic limestone
  • Byproduct fluorosilicic acid

65
Fluoriteproduction
66
Fluoritegeology
  • Rio Grande Rift (RGR) deposits
  • Mississippi Valley type (MVT) deposits
  • Sedimentary stratiform deposits
  • volcanic massive sulfide deposits
  • gangue in epithermal and mesothermal veins

67
Garnet
68
Garnet
  • Latin granatus (grain")
  • possibly a reference to the Punica granatum
    ("pomegranate"), a plant with red seeds similar
    in shape, size, and color to some garnet crystals

69
Garnetintroduction
  • group of complex silicate minerals with similar
    crystalline structures
  • A3B2(SiO4)3, where A can be Ca, Mg, Fe, Mn B can
    be Al, Cr, Fe, Ti

70
Garnetintroduction
  • aluminum garnets
  • almandine or almandite
  • pyrope
  • grossularite
  • spessartite
  • iron garnets
  • andradite
  • chromium
  • uvarovite

71
Garnetproperties
  • Various colors
  • isometric
  • specific gravity 3-4
  • Luster is vitreous
  • Hardness is 6.5 - 7.5

72
Almandine
http//en.wikipedia.org/wiki/Garnet
Andradite
73
Garnetuses
  • waterjet cutting, 35
  • abrasive blasting media, 30
  • water filtration, 15
  • abrasive powders, 10
  • other end uses, 10

74
Garnetsubstitutions
  • natural and manufactured abrasives
  • Ilmenite
  • magnetite
  • plastics

75
Garnetproduction
76
Garnetgeology
  • Gneisses and schists
  • contact-metamorphic deposits in crystalline
    limestones
  • pegmatites
  • igneous rocks
  • serpentinites
  • vein deposits
  • alluvial garnet

77
Graphite
78
Graphite
  • Greek (graphein) to draw/write
  • for its use in pencils

79
Graphiteintroduction
  • C
  • confused with molybdenite, which is denser and
    has a silver blue streak
  • gray streak
  • Luster is metallic to dull
  • Cleavage is perfect in one direction

80
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81
History
  • First use of graphite primitive man to make
    drawings, and by Egyptians to decorate pottery.
  • Graphite processing 1400 AD in the Haffnerzell
    District of Bavaria.
  • Through the Middle Ages graphite was confused
    with galena and Molybdenite.
  • First names Plumbago (lead -silver) black lead
  • Discovered 1565 by Gessner (recognized as a
    mineral), but its composition was determined in
    1779 by Scheele.

82
Graphiteproperties
  • Milled, drilled and turned in a lathe to a
    desired shape
  • Making Brushes
  • conductive
  • chemically stable
  • high strength
  • hardness 1-2
  • specific gravity 2.2
  • good conductor of electricity
  • lubricant

83
Physical Characteristics
  • Color is dark gray, black, or black silver.
  • Luster is metallic to dull.
  • Transparency crystals are opaque
  • Crystal System is hexagonal
  • Hardness is 1 - 2
  • Specific Gravity 2.2
  • Cleavage is perfect in one direction.
  • Fracture is flaky.
  • Streak is black gray to brownish gray.
  • Melting Point of 3,500ºC.
  • Graphite is an excellent conductor of heat and
    electricity.
  • Other Characteristics thin flakes are flexible
    but inelastic, mineral can leave black marks on
    hands and paper.
  • Best Field Indicators are softness, luster,
    density and streak.

84
Mineralogy
  • Graphite is a native element composed only of
    carbon. It has the same composition as diamond,
    however it has very different structures.
  • Diamond crystallizes in the Isometric system X
    graphite crystallizes in the hexagonal system.

Source- http//www.chem.ox.ac.uk/icl/heyes/structu
re_of_solids/Lecture1/Lec1.html
85
Graphite
http//www.phy.mtu.edu/faculty/info/jaszczak/borro
wdale.html
86
Graphiteuses
  • Refractory applications 45 (brick and linings)
  • brake linings 20
  • lubricants, 5
  • dressings and molds in foundry operations, 5
  • other uses 25

87
END-USES
Main uses are in refractors, lubricants, brake
linings, foundry moulds, and electrodes.
Non-traditional applications include expanded
graphite and graphite foils (a thin graphite
cloth).
Graphite Foils
Graphite Packing
Expanded Graphite
88
Graphitesubstitutions
  • graphite powder
  • scrap from discarded machined shapes
  • calcined petroleum coke
  • Molybdenum disulfide
  • Finely ground coke with olivine

89
Graphiteproduction
90
Graphitegeology
  • Types of Natural Graphite
  • Disseminated flake
  • Crystalline vein (lump or high crystalline
    graphite)
  • Amorphous
  • Graphite occurs in many types of igneous,
    sedimentary metamorphic rocks. The more
    important are those found in metasomatic
    hydrothermal deposits, in sedimentary rocks
    that have been subjected to regional or thermal
    metamorphism.
  • Associated Minerals include quartz, calcite,
    micas, iron meteorites, and tourmalines.

91
Geology
  • Flake graphite
  • is found in metamorphic rocks uniformly
    distributed through the ore body or in
    concentrated lens shaped pockets. 
  • Graphite flake occurs as a scaly or lamella form
    in certain metamorphic rocks such as limestone,
    gneisses and schists. 
  • Carbon concentrations vary between 5 and 40.
  • Flake graphite occurs in most parts of the
    world.  Notable deposits are Canada, Brazil,
    Madagascar, Australia, USA(Texas-1980, Alabama
    Pennsylvania-1960s), Germany
  • Flake marble, gneiss, and schist (most common
    rock types)

Source -http//www.alibaba.com/catalog/10876290/Na
tural_Flake_Graphite.html
92
Geology
  • Crystalline vein graphite
  • is believed to originate from crude oil deposits
    that through time, temperature and pressure have
    converted to graphite.
  • Vein graphite is found along the intrusive
    contacts of pegmatites with limestone.
  • The vein fissures are typically between 1cm and 1
    m thick, and are normally gt 90 pure.
  • Although this form of graphite is found all over
    the world, it is only commercially mined in Sri
    Lanka.

Source - http//www.asbury.com
93
Geology
  • Amorphous graphite
  • Amorphous graphite is found as minute particles
    in beds of mesomorphic rocks such as coal, slate
    or shale deposits.
  • The graphite content ranges from 25 to 85
    dependent on the geological conditions.
  • Most of the amorphous deposits with economic
    importance are formed by metamorphism of coal or
    carbon rich sediments.
  • Notable occurrences are in Mexico, North Korea,
    South Korea and Austria.

Source - http//kuroko.mus.akita-u.ac.jp/sampimag/
11767e.htm
94
Artificial Graphite
  • Synthetic graphite can be produced from coke and
    pitch.
  • Synthetic Graphite consists mainly of graphitic
    carbon that has been obtained by graphitisation,
    heat treatment of non-graphitic carbon, or by
    chemical vapour deposition from hydrocarbons at
    temperatures above 2100K .
  • Synthetic Graphite tends to be of higher purity
    though not as crystalline as natural graphite.
  • On the whole, synthetic graphite tends to be of a
    lower density, higher porosity and higher
    electrical resistance.
  • Its increased porosity makes it unsuitable for
    refractory applications.

Source - http//www.intertrade.com.
95
Mining Method
Graphite is commonly extracted through open-pit
methods. In some cases, it has been extracted
through underground mining (vein deposits in Sri
Lanka). Mining - Graphite ore is extracted with
the  use of shovels bulldozers that load dump
trucks with the crude ore. Mechanical
concentration - The ore is crushed by a primary
crusher and then submitted to  a series of roll
crushers and classifiers to remove the oversizes
and gangue. Flotation is used for the mechanical 
separation of the graphite from impurities
present in the  ore. The cycle mill-flotation is
repeated until a grade between 87 -96 of carbon
is reached. Chemical concentration -
Concentration with the use  of chemical agents is
used to remove impurities that  remain in the
graphite after the mechanical concentration 
process. Some firms make high purity graphite
(98 - 99carbon) by leaching concentrate with
strong acids or alkalis.
Primary Crusher
Mill
Flotation Cells
Dryers
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