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Principles of Metallurgy > Lesson 2 > Flashcards

Lesson 2 Flashcards

1
Q

also termed as Mineral
Dressing, Ore Dressing, Mineral Beneficiation,
Milling, is defined as the Mechanical Separation of
valuable minerals (ore concentrate) from valueless
minerals (gangue).

A

Mineral Processing

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2
Q

The two (2) fundamental operations in mineral
processing are

A

Liberation and Separation

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3
Q

Fundamental Operation sa Mineral Processing

the release of the valuable
ore from the waste minerals

A

Liberation

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4
Q

Fundamental Operation sa Mineral Processing

concentration of these valuable
minerals from the gangue

A

Separation

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5
Q

performed in between mining
and production of metal
products

ma get get pow rana sabti lang jud huhuhu

between daw??? so unsa man

A

Mineral Processing

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6
Q

OBJECTIVE

  • To bring the valuable mineral or the final product
    into suitable technical condition as required by the
    process
  • Undesired constituents of the original ore must be
    removed or reduced below the specified units
A

Technical

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7
Q
  • To provide the cheapest way to eliminate the
    unwanted minerals
  • Reduce unit material handling costs
  • Mineral Processing must be cost-efficient!

COST????COST!!!! KWARTA

A

Economic

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8
Q

Concentration of desired mineral =

Tinipid langs

A

Freight Savings

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9
Q

The essential prerequisite for the
separation of an ore into valuable and
waste fractions

prereq daw oh

fundamental sis sa min pro

A

Liberation

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10
Q

Waste Rock Minimization =

para asa pud

A

Improve metal purity

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10
Q

Effective Material Reduction =

para asa pud

A

Reduced Treatment charge

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11
Q

it is impracticable if the 1st step
has not been successfully accomplished!

A

Separation

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12
Q

– Uncrushed rock

unsa sha na size

A

grains, grain size

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13
Q

Crushed rock

unsa na siya na size

A

Particles, Particle size

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14
Q

Particles can consist of a
single mineral;

A

Free particle

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15
Q
  • particle size reduction by breaking,
    crushing, or grinding of ore, rock, coal,
    or other materials
  • It is a critical component in most mineral
    processing flowsheets and can serve
    several purposes
    Goals: LIBERATION and
    SEPARATION
  • Done either wet or dry
  • Consumes a lot of energy
    (>40% of total Mine/Mill
    consumption)

Unit operation ni sha bayot ha

A

Comminution

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15
Q

When a particle consists of
2 or more minerals,

A

Locked Particle

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16
Q

Stages of Crushing

PRIMARY

ENUMERATE YOT

A

– Jaw Crushers
– Gyratory Crushers

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16
Q

Stages of Crushing

SECONDARY

ENUMERATE YOT

A

– Cone / Gyrasphere Crushers
– Roll Crushers
– Hammer Mills
– Impactors

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17
Q

– Consists of 2 crushing faces or jaws,
* one stationary and rigidly mounted
* one jaw reciprocates to and from the face in a small
throw

– The different types feature the positioning of the
pivot of the movable jaw

A

Jaw Crusher

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18
Q

– Invented in (1)____ by (2)________
– Movable jaw is pivoted at the (3)____ by cross
shafts
– A motor drives an eccentric shaft, transfers
the reciprocating motion to the jaw

unsa ni siya na type?

A

BLAKE TYPE

  1. 1885
  2. Eli Whitney Blake
  3. Top
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19
Q

Dodge Type
– The movable jaw is fixed at the (1)_____
– Key feature is large reduction ratio and a
closely-sized product
– Disadvantage is its low-capacity operation,
since the choke point coincides with the point
of least motion

unsa ni siya na type?

A

DODGE TYPE

  1. bottom
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20
Q

– Modifications of Dodge and Blake
– The motion of the movable shaft is a direct
result of the circular motion of the eccentric
shaft
– Uses less space than Blake or Dodge

wow the connection!!!

A

Single Toggle/Overhead Eccentric

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21
Q

– Originally patented by
(1)______ in (2)_____
– Relative motion of the
crushing faces is due to
gyration motion of an
eccentrically mounted
cone

UNSA NI NA CRUSHER!??!?!??!

A

GYRATORY CRUSHER

  1. Philetus Gates
  2. 1881
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22
Q

– At any cross-section,
there are in effect 2
sets of jaws opening
and closing like jaw
crushers

A

Gyratory Crusher

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23
Q

Three types of Gyratory Crushers

ENUMERATE YOT

A

– Suspended spindle
– Supported spindle
– Fixed spindle

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24
Q

There is a fixed crushing
surface (______) shaped
like an inverted cone
frustrum

unsa pud?

A

Concaves

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25
Q

and a movable crushing
surface (_____), also
conically shaped, w/c
gyrates w/in the interior of
the concave cone

A

Mantle

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26
Q

(1)
* Lighter than the heavy-duty, rugged *primary
Crushers
* Maximum feed size ~ (2)____
* “clean” feed (no harmful constituents)
* Final feed is of size suitable for grinding
circuit

A
  1. Secondary Crushers
  2. 15 cm
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27
Q

DIfference between CONE CRUSHERS and GYRATORY CRUSHERS

kadtong naka box kay di ko kabalo unsaon hays

yes tong opposite opposite langs

A

Cone crushers
1. Short Spindle
2. Spindle is not suspended
3. Downward Flare bowl
4. Spring-protected bowl

Gyratory crushers
1.Longer spindle
2. Suspended spindle
3. Upward flare concave
4. No spring for the concave

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28
Q

– tertiary crushing
– Crushing by interparticle comminution
– Short, Flat-angle liners
________ action:
– Combination of impact
and attrition
– No single-layer
crushing occurs!

interparticle comminution ako term ani kay unique….

unique!??!??!?!

A

Gyradisc Crusher

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29
Q
  • The rolls are fitted with a series of inter-meshing
    teeth or “slugs” w/c protrude from the roll
    surfaces
  • Crushing action is by compression and ripping
  • Used for softer, sticky materials for larger Rr

sharo naa nay term na slugs oh

A

Toothed/Slugger Roll Crusher

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29
Q

– Spherical crushing head
– The crushing bowl is held by spring in
compression (vs. tension in CC’s)

SPHERE DAW BAYOT

A

Gyrasphere Crushers

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30
Q
  • Consists of two horizontal cylinders
    revolving towards each other
  • Spring loaded rolls are adjusted for the
    set; held back against the solidly mounted
    roll
  • Single pressure only! (vs. continuous w/
    JC, GC, CC)

roll on hahahhaa

A

Roll crushers

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31
Q
  • Comminution by impact;
    sharp blows on free-falling
    rock
  • Used on materials behaving
    plastically on slowcompression crushing
  • Uses beaters to transfer
    kinetic energy to particles
A

HAmmer mills/Impactors

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32
Q

(1)

  • The hammers are attached
    to a rotor w/c sweeps along
    the path of free falling
    rocks
  • Pivoted hammers
  • Hammers and breaking
    plates are made of
    (2)______
A
  1. Hammer Mills
  2. Manganese Steel
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33
Q

HAMMER MILLS

  • Hammers can weigh up to (1)_____
  • Feed size up to (2) _____
  • Rotor speeds between (3) _____

hahahahha keri pa beh?

A
  1. 100kg
  2. 20cm
  3. 500-3000 RPM
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34
Q

(4)_______

  • Used for coarser crushing; (1) ____
  • Fixed hammers
  • Grinding path – successive breaker
    plates with decreasing clearances;
    produces better control of product size
  • Rotor speed is (2)____
  • Feed rate (3)______
A
  1. F ~ 1.5 m
  2. 250 – 500 RPM
  3. 1500 – 3000 MT/h
  4. Impactors
35
Q
  • Impact crushing + High-intensity grinding +
    multi-particle pulverizing

pulverizing!!!!!

A

Tidco Barmac Crusher

36
Q
  • Operates like a cylindrical trommel
A

Coal Breakers

36
Q

– Grinding in one pass

A

Open Circuit

37
Q
  • “Mechanized Mortar and Pestle”
  • Rr = 150:1
A

Stamp Mills

37
Q
  • Last stage of comminution
  • Size reduction by impact + abrasion
  • Done either wet or dry
  • Performed primarily on rotating cylindrical steel
    vessels (tumbling mills)
  • May or may not use grinding medium (balls or rods)
A

Grinding

38
Q

– Controlled by feed rate (<45% mill volume)

kadtong hentai gale HUIEEEEEE

A

Overflow

39
Q

– The mill discharge is passed through a sizing
product
– The oversize particles are re-circulated

A

Closed Circuit

40
Q

– Prevents early discharge of oversize and
grinding medium
– Removal of fines, prevents over-grinding

A

Grate Discharge

41
Q
  • Mixture of ore, water, and grinding media
A

Mill Charge

42
Q

– Minerals are
susceptible to physical
and chemical changes
with water

A

Dry Grinding

43
Q

– Lower kWh/Mt
– Higher Mt/m3 mill
volume
– Closer product control
by classification
– Elimination of dust
– Simpler handling;
pumps and launders

A

Wet Grinding

44
Q

– Rolling motion of the charge down to the toe
– Leads to finer grinding by abrasion (↑liner
wear)

A

Cascading

45
Q

– Parabolic path taken by charge as projected
by lifting of the mill
– Coarse grinding by impact (↓liner wear)

A

Cataracting

46
Q

– Charge is carried around in a fixed position

A

Centrifuging

47
Q

it is adjusted to control the
trajectory of the GM; to hit the ore, not the
mill liners!

A

Mill Speed

47
Q

TM’s are normally operated bet. __% -
__% of critical speed

A

50-90%

48
Q
  • Uses cast iron rods as grinding medium
  • Rr
    = 15-20:1
  • Length is 1.5-2.5x the diameter
  • Max length of rods = 6m; 25-150mm Φ
  • Rated based on power consumption
  • Operated at 35% mill volume; 50%-65%
    critical speed; 65-85% solids

cast iron rods daw oh

A

Rod Mills

49
Q
  • Rod Mills are practically always run in
    ______

in unsa?

A

Open Circuit

50
Q
  • Uses forged steel balls as
    grinding medium
  • Length is 1-1.5x the diameter
  • Operated at 65%-80% solids;
    40%-50% mill volume; 70%-80%
    critical speed
  • 10 uses 5cm-10cm balls; 20 uses
    2cm-5cm
  • Mill capacity is increased by
    length; specific capacity is
    increased by diameter (energy)

forged steel balls daw oh

A

Ball Mill

51
Q

Higher mill rotation speeds – ______ is
dominant

A

Cataracting

51
Q

Ball Mills are often operated in _________ to minimize over-grinding

A

CLosed Circuit

52
Q
  • The action of the ore grinding upon itself
  • Uses tumbling to effect grinding; little or no
    medium!
  • Rr up to 250
  • L:D ~ 1:2
  • SAG – 6%-10% mill volume ball charge
  • Operated at 75%-90% critical speed
A

Autogenous/ SAG Mills

53
Q
  • The main mechanism for grinding is by

by????

A

Abrasion

54
Q

the size at w/c the particles
inside the AG is already too small for
efficient grinding

A

Critical Size

55
Q

Useful Range of ELUTRIATION

AHAHHAHHAHAHHAHAHA

A

40-5

55
Q

Useful Range of TEST SIEVES

AHHAHHAHAHHAAHHAH

A

100000 – 10

55
Q
  • Segregation of Materials into products
    characterized by difference in size
  • Screening and Classification

Unit Operation in Mineral Processing

A

Sizing

56
Q

Useful Range of SEDIMENTATION (CENTRIFUGE)

heheheh

A

5-0.05

56
Q

Useful Range of MICROSCOPY

bleee

A

50 – 0.25

57
Q

Useful Range of SEDIMENTATION (GRAVITY)

sge gow

A

40 – 1

58
Q

Useful Range of ELECTRON MICROSCOPY

korek

A

1-0.005

59
Q
  • One of the oldest methods
  • Most widely used due to effective
    size range
  • Done by passing a known weight
    of sample through successively
    finer apertures to determine the
    weight for each fraction
  • Wet or dry
  • Agitated
A

Sieve Analysis

60
Q

COMPLICATION IN SIEVING

duha ni sila

A

-irregularly shaped particles
-near size particles “blinding”

61
Q

*Designated by nominal aperture sizes
– Sides of square or diameter of circle aperture
* Mesh no. ≈ # of square apertures/inch2

A

test sieves

62
Q
  • Machine Sieving using the (1)____
  • Sieves are stacked in increasing mesh
    no.
  • Sample is placed on (2)_____, coarsest
    sieve
  • Agitated vertically and horizontally
  • Fraction retained per sieve is weighed
A
  1. Ro-tap
  2. topmost
62
Q
  • Prevent entry of undersize into crushing
    machines
  • Prevent oversize from moving onto the
    next stage in closed circuit grinding
  • Prepare a closely sized end product
A

Industrial Screening

63
Q

STATIONARY SCREENS
(?)
– 20mm – 300mm, 1000tph max
– 20 – 500 deck angle
– Uses heavy parallel bars

A

Grizzly

64
Q

STATIONARY SCREENS

– >50μm, 180m3/hr
– Curved screen w/
horizontal wedge bars
– Slurry enters tangentially to
the bend
– Peeling action of the slurry
bed

A

Sieve Bend

65
Q

STATIONARY SCREEN

– 6 –55mm
– Slightly inclined, rotating
cylindrical screen
– May be made in series, or with
concentric cylinders of increasing
aperture sizes (compound
trommel)

A

Revolving Screen/Trommels

66
Q

MOVING SCREEN
(?)
– 250μm – 25cm
– Most important screens
– Multi-decks

A

Vibrating Screens

67
Q

?

WHat is the basis for separation????

?

?

A

velocity of the particles as the grains fall through a fluid medium

68
Q

shear forces between
medium and mineral surface

A

Viscous Resistance

69
Q

due to displacement
of fluid by the mineral

A

Turbulent Resistance

70
Q

– pt. of 0 acceleration
Gravity ≈ Resistant Forces

A

Terminal Velocity

71
Q
  • a system with a large volume of medium
    relative to particles
  • No particle crowding (<15% solids w/w)
A

Free Settlings of Particles

72
Q
  • ↑pulp density; each mineral particle
    is covered w/ thin film of water
  • Slurry acts as a viscous fluid; only
    coarse particles can penetrate
  • Most important concept in
    classification / sorting columns
  • Larger particles settle at the
    bottom, finer ones are carried
    away by current (w/ scouring
    action)
A

Teeter Condition

72
Q

(1)

  • The case where there is an increase in
    pulp density (>15% solids w/w)
  • ↑pulp density, ↑viscosity, resistance is
    mainly due to (2)____
A
  1. Hindered Settling
  2. Turbulence
72
Q
  • Continuous classifier that
    uses centrifugal force to
    accelerate the settling rate of
    particles
  • Widely used in MP for fine
    separation and closed- circuit
    grinding due to short retention
    time
A

Hydrocyclone

72
Q

TYPES OF CLASSIFIERS

  • Mechanical Classifiers
    – Rake Classifier
    – Spiral Classifiers
    →Pulp feed is introduced to inclined through;
    coarser, heavier particles settle at the bottom
    and is dragged against a flow of liquid
    →Finer particles report to overflow discharge
A

Horizontal Current Classifiers

73
Q

TYPES OF CLASSIFIERSSSSS

  • Vertical type: hindered settling; effects on density
  • Multiple (series) sorting columns w/ rising water
    current from bottom
  • Faster currents at the 1st column, slowest at the last
    – results in the grading of the slurry from coarser,
    denser particles to finer ones!
  • Volume of chambers increase successively
A

Hydraulic Classifiers

73
Q

Mechanism for removal of coarse / dense
minerals is a rake system moving up an
incline

A

Rake Classifier

74
Q
  • Uses a continuous moving spiral to move
    sands up a slope
  • May be used at steeper slopes (de-H2O)
A

Spiral/Screw Classifier

75
Q

HYDROCYCLONE

  • The feed is introduced
    under pressure by
    (1)______ entry w/c
    imparts a swirling motion
    of the pulp
  • This generates a (2)______
    inside, w/ a low pressure
    zone along the vertical
    axis
A
  1. Tangential
  2. Vortex
76
Q
  • Separation of valuable minerals
  • Based on the physical characteristics of
    minerals
A

Concentration

77
Q
  • Solid/liquid separation by thickeners
    and filters
A

Dewatering

78
Q
  • Bins, conveyors, feeders, pumps, etc.
A

Auxiliary Operations

Principles of Metallurgy (13 decks)

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