Metallurgy Flashcards
1
Q
3 branches of Metallurgy
A
1) Extractive
2) Physical
3) Adaptive
2
Q
Preparation required before the extraction process
A
Ore Dressing
3
Q
A localized plastic deformation
A
Necking
4
Q
Minimum strength that will promote plastic deformation
A
Yield strength
5
Q
Capacity to absorb energy when it is deformed elastically
A
Resilience
6
Q
How is a Rockwell Hardness Test performed
A
find difference in depth of penetration bet a minor and a major load using diamond cone
7
Q
How is Brinell Hardness test done
A
w. a Hard spherical indenter and measure indent for a specified load and time
8
Q
Izod Impact test is done by
A
placing specimen vertically and 167 J impact
9
Q
Charpy impact test is done by
A
hor specimen, 300 J load
10
Q
Knoop and Vickers is done using a
A
diamond indenter for brittle materials only
11
Q
Fatigue def
A
metal’s response to cyclic loading
12
Q
Creep def
A
time dependent deformation under constant load and/or high temp
13
Q
3 types of Extractive processes
A
1) Pyrometallurgy
2) Electrometallurgy
3) Hydrometallurgy
14
Q
Ore type where pyro met is easiest
A
Oxide minerals
15
Q
How is smelting done
A
1) Use carbon as a reducing agent
2) Convert oxide to molten state
3) Alllow SG for metal to separate from the slag
16
Q
How are Carbonate ores treated
A
by separating into metallic oxides and CO2 thru heating
17
Q
How are Silicate ores treated
A
same for oxide plus removal of silica
18
Q
How are Sulfide ores treated
A
for matte in smelting operations
19
Q
How are Sufide ores prepared
A
by adding elemental sulfur to molten metal
20
Q
How is sulfur removed
A
by oxidizing to sulfur dioxide gas
21
Q
Treatment of metal product to remove impurities
A
Refining
22
Q
What is a Shaft furnace and its efficiency
A
charge in contact with fuel (thermal efficiency of 60-70%)
23
Q
Reverbatory furnace is a
A
Heat from firebox passes to the charge then is exhausted
24
Q
Describe Muffle, Crucible, and Retort
A
heat is conducted through wall, low thermal efficiency
25
Pyrolysis means
destructive distillation of coal in the absence of air
26
What is Calcination process
process of heating the ore at a temp not suff to melt ore, in absence of air
27
When is Calcination done
Covert carbonate ores into oxide and CO2
| CaCO3 ---> CaO + CO2
28
What is Roasting
heating of ore in presence of excess air
29
When is Roasting done
convert metal sulfides into metal oxides and sulfur dioxide
| 2Cu2S + 3)2 ---> 2Cu2O + 2SO2
30
What is sulfatizing roast
Oxide is turned into metallic sulfate
| CuO + SO3 ---> CuSO4
31
What is blast roasting
air is supplied by fan or blower
32
What is flash roasting
used in very fine sulphide material (flot concentrates)
33
What is smelting
process of melting and separating into two immiscible liquids
34
Converter process
presurized air is blown through molten charge
35
Molten solutions of sulfides
Matte
36
Molten solution of arsenides
Speiss
37
What is dross
Collective term for Sollid impurities floating on molten metal
38
What are refractories
Accepts molten charge
39
2 types of Heat Exchanger
Recuperators (continuous transfer) and Regenerators (stores heat)
40
Why is Roasting done
to convert metal into soluble form and remove volatile impurities, and to weakn bonds
41
What is used to leach Cu-Zn, and gold- silver allow
Sulfuric Acid
42
Base NH4OH used to leach what
Copper
43
NaOH is used to leach what
bauxite
44
NaCN or KCN is used to leach what
Au and Ag
45
Vat or Percolation leaching is used for
5 mm diameter material, lasts days
46
Fastest type of leaching (hours)
Agitation leaching
47
Why is Pressure leaching done
for minerals difficult to dissolve at ordinary temp and pressure
48
SPC means
Separation - Purification - Enrichment
49
What is SPC by Ion exchange
used of polymeric resin to exchange ions
50
Steps in Ion-Exchange
1) Sorption - pregnant soln passed thru resin column to exchange ions
2) Elution - ions are removed from resin by passing eluan or renerant which has excess electrolyte
51
What is Adsorption process
use of activated carbon to takeup ionic or molecular substances preferentially
52
Explain Solvent Extraction
partitioning of metal into immiscible phase - aqueous and organic (aqueous w/ valuable)
53
Metal winning precipitation is done by
formation of solid product from solution using reagents
54
Electromet is done by
deposition of metals at cathode
55
Cadmium is precipitated using
Zinc dust
56
Zinc purification is done by
Neutral circuit leaching
57
Zinc dissolution is done by
Acid circuit leaching
58
Explain Amalgamation
1) Mercury leaches Gold to form Amalgam
2) Retort furnace is used to vaporize Mercury and condensed for reuse
3) Gold Amalgam is left in the furnace
59
Furnace using electricity for heat
Arc furnace
60
Explain Oxidation
involves loss of electrons
| Fe0 ->Fe2+ + 2e-
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Explain Reduction
involves gain in electrons
| Cu2+ + 2e- -> Cu0
62
Oxidation occurs here
Anode
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reduction and deposition occurs here
Cathode
64
Electrolyte is the
aqueous medium thru w/c ions move from one electrode to another
65
Explain Electrowinning
1) Anode site provides the electrons
| 2) The cathode uses electron to recover metal
66
Explain Electrorefining
Anode is dissoved into solution
67
Betts process means
Crude lead is refined (only if Bismuth is present)
68
Process to remove Silver and Gold from lead bullion
Parkes process
69
Nickel is is prod electrolytically by
Bessemer matte using a nickel sulfate solution w/ boric acid
70
Silver bullion is refined electrolytically by
Thum or Moebius process
71
Wohlwill process is
Electrolytically refining Gold bullion
Selective deposition of Gold using REDOX reactions
72
What is electroplating
surface coating of metal on metallic object thru cathodic depostion
73
Used to refine Al
Bayer Process
74
Define Isotopes
same number of protobs, diff number of neutrons
75
Explain allotropy
Change in structure when heated
76
What is metallic bond
all positive cores share electrons
77
Metal which is non-crystalline at room temp
Hg
78
Liquid w/c is non-amorphous
Crystalline polymer
79
3 Principal metallic structure
BCC
FCC
HCP
80
How many Bravais lattice
14
81
What is Diffraction
Constructive interference of scattered x-rays
82
Alloying is done by
1. Metal base is melted
| 2. Additive are added as solids to be dissolved
83
2 common types of Metal Fabrication Processes
1. Forming
| 2. Casting
84
Forming operations
F orging
R olling
E Extrusion
D rawing -
85
Casting operations
D ie - force molten material under pressure
I nvestment - Wax is molded, ceramic mold takes its place as wax melts, molten material poured
C ontinuous - cast into continuous strands
S and - as mold material
L ost Foam Casting - Foam is replaced with hardened metal
86
2 Miscellaneous operations
Powder metallurgy
| Welding
87
Hot Working use
Large strains can be achieved
88
Forging def
use of compressive stress to deform metal
89
Rolling def
Reducing of thickness and change in shaped using pair of revolving rollers
90
Extrusion def
Forcing hot block of metal thru a die orifice under high pressure
91
Drawing def
Pulling metal thru exit side of die
92
Casting def
Molten metal solidify in mold
93
How is Powder met done
1. Powder is prod by mech, electro, chem, atomization process
2. Compacted using punches
3. Heat for inter-particle weld
94
Mechanical joining
Bolts, Rivets, Screw, Snap fit
| S
95
Soldering def
Bonding sep pieces by melting metal
96
Most common bonding material
60-40 lead-tin
97
Brazing def
similar to soldering but using Ag or Cu alloys
98
What is CIP/CIL
Selective dissolution of Gold using cyanide for >3% Au feed
99
What is Miller process
Chlorine gas is passed thru molten gold to ppt other metals
100
What is HPAL and MOA Bay process
Use of Sulfuric acid leaching of Ni into Sulfate
101
What is Sherritt Gordon Process
Ammonina (NH3)leaching of Ni
102
Mitsubishi Process is the
Continuous Furnace smelting of Cu into copper matte
103
Flash smelting is
under Mitsubishi Process, Autogenous fine particle smelting of Cu
104
Blast furnace smelting is used to extract what
Iron
105
What is Midrex/COREX process
Direct Iron Oxide Reduction
106
5 Unit Operations in Ore Dressing
```
Comminution
Sizing
Concentration
Dewatering
Auxilliary Operations
```
107
2 Means of Liberation
Size reduction and detachment
108
When is "Grain" used
for Uncrushed rock
109
When is "Particle" used
Crushed rock
110
Reaction that reduces iron to pig iron
Boudard reaction
111
Two types of Liberation due to fracture
Intergranular
| Transgranular
112
4 types of middlings
Rectilinear
Vein
Shell
Occlusions
113
Rittinger's formula (Surface area)
E = K(Final area - Initial area)
114
Kick's Energy Law (Change in size)
E = K*ln(Initial Diameter / Final Particle Diameter)
115
Bond's Energy Law (Crack length)
E = K * (1/sqrt(Final diam) - 1/ sqrt(Initial Diam))
116
Reduction ratio (Rr)
feed opening/ product opening
117
Geometry factor for Kick's
n = 1.0
118
Geometry factor for Bond's
n = 1.5
119
Geometry factor for Rittinger's
n = 2.0
120
Rod mill L:D
1.5-2.5 : 1
121
Ball Mill L:D
1-1.5 : 1
122
AG/SAG L:D
0.5 : 1
123
SAG volume ball mill charge %
6-10%
124
Mass Balance Eqn
F = C + T
125
Elemental Balance equation
fF = cC + tT
126
What is MOG
Size to w/c ore is ground to ensure sufficient liberation
Normally 80% passing
127
Mesh no. equals
of square apertures/in^2
128
GGS formula
Cumulative passing vs LOG(passing size)
129
Concentration ratio in terms of assay
K = (c-t)/(f-t)
130
Recovery in terms of assay
R = c*(f-t)/f*(c-t)
131
Enrichment ratio
Er = c/f
132
2 methods of Sizing
Screening - Use of physical barriers
| Classification - diff'l movement of solid particles thru fluid
133
2 Screen movements
Frequency - hor'l movement
| Stroke - Vertical movement
134
Limit of Industrial screening
Mat'l over 250 microns
135
Dual Vibrating screens has how many products
3 (2 over size, 1 under size)
136
Terminal velocity meaning
Equilibrium attained bet gravitational and fluid resistance forces.
Bouyant force + Drag force - Gravitational force = 0
137
Free settling is the
settling in a vol of large fluid vol wrt total vol
138
Effect of flowing film wrt to SG and Diameter
the high SG low D is less affected than high SG high D,
139
What is High-tension separation done
Uses diff in electrical conductivities to sep feed
140
Theory behind froth flotation
Driving force for attachment of part's to bubbles is the REDUCTION OF SURFACE ENERGY of the system
141
Allotrope of Sphalerite
Wurtzite
142
What are Surfactants
Surface active chemicals that affect dynamics at interface
143
What do collectors do
makes surface hydrophobic
144
What is the Polar group and Hydrocarbon chain
Polar group attaches to mineral while Hydrocarbon chain makes it hydrophobic to water
145
What do Frothers do
Control stability of bubbles
146
What do Conditioners do
Control pH w/c in tur dictates the surface charge
147
What do Modifiers do
affect adsorption efficiency of collectors on min surface
148
2 types of Modifiers
Activators - adsorbent to collector
| Depressants - suppresses adsorption of collector
149
Working slope for Chutes
45-55%
150
What are tensioning devices
to prevent undue sag on conveyor belt
151
What are snub pulleys
to increase tension
152
What are drive pulley
receives torque from motor to move belt
153
What is a counter-weight in conveyors
To add tension in conveyor
154
Interlock systems are used to
stop preceding conveyors when one fails
155
What do belt-loading systems do
Load ore same speed as belt
| Centers ore on belt
156
Elliptical Bar feeder advantage
Move large rocks along while letting thru smaller ones
157
Most widely used feeder for coarse materials
Apron feeder
158
What is a live storage stock pile
There is a draw bell and a conveyor under the stockpile
159
How are orebins used
intermediate bet crushing and grinding
160
When are sloping bottom ore bins used
for easily oxidized ore
161
Slurry/Conditioning tanks are used
Store suspensions of fine solids
162
Non-white or nearly white metals
Au and Cu
163
Ferromagnetic mineral
Fe, Ni, Co
164
What is toughness
ability to absorb energy up to fracture
165
Reagnet which lowers surface tension; reagent conc at bubble
Organic frother
166
Reagent increases surface tension; reagent conc away from surface
Inorganic frother
167
Effect of electrolyte ph in frothing
Acids - dec froth
| Alkali - inc froth
168
Collector for most sulfide minerals
Xanthates
169
Other name for "Aeroflot" a collector for sulfides
Dithiophosphates
170
Collector for alkali earth metals,some carbonates, and oxides
Carboxyl
171
Collector Applied for silicates
Cationic
172
Depressants fxn
Make hydrophobic to hydrophilic
173
Activator fxn
To help adsorb collector making it hydrophobic
174
What do regulators do
pH modification
175
pH of flotation slurry for all sulfide ores
alkaliine
176
Column flotaion descrp
Feed at top
Air sparger makes bubble at bot
Cleaning zone at top
Conc output at top
177
Net downward flow of water maintained inColumn flotation
Positive Bias
178
Jameson Cell fxns by
Feed and air slurry jet is injected
Wash water at top removes entrained tais
Conc at top
Tails at bot
179
Adv of Jameson
Fast, bc contact dependent not residence time dependent
180
Denver flotation cell works by
Impeller at bot sucks in slurry and pressurized air from top
181
Most widely used flotation machine
Wemco cell
182
Wemco feature
rotor-disperser, no need for pressurized air
183
Outokumpu Cell feature
Impeller design
There is an impeller surrounded by vert slots called diffuser
Air is pumped also
184
Particle size range for flotation
10 to 150 microns
185
carat to mg
1 carat = 200 mg
186
Pa to Bar
100,000 Pa = 1 bar
187
Hp to kW
1 Hp = 0.746 kW
188
cal to kJ
1 cal = 4.184 kJ
189
Relation of attachment porbabitlity to diameter
inversely proportional
190
Pulp density must be kept:
- As dense as possible, so coarse can sep from fines
| - but dilute enooguh for particle rearrangement
191
Effect of temperature in flotation
- Increased flotation room
| - inc solubility of reagents
192
DMS is most effective for
Metalliferous ore with light gangue
193
What is a LARCODEM
Large Coal Dense Medium Separator
194
Energy law: >1 cm
Kick's
195
Energy law: 10 - 1000 microns
Rittinger's
196
Energy law: 1 cm - 10 microns
Bond's
197
Measures or energy nec to break an ore
Work Index
198
Net profit =
Revenue - Cost - Deductions
199
Roughing descrp
1. Uses mod seperating force to rem liberated minerals
| 2. Rec of bulk of conc
200
Scavenging Descrp
1. Receives tailings from rougher
| 2, Strong sep force for incompletely liberated minerals
201
Receives rougher concentrate
Cleaning
202
When to use Rougher-Scavenger
If Recovery is more important than grade
| In pyritic gold, transport cost is less than add'l cleaning
203
When is Rougher - Cleaner used
When Conc. grade is important
| for easily recoverable ores
204
Feed Character for impactor
Soft feed
205
Why are Rod mills run in open circuit
due to evenness of product
206
What are reclaimers
Stockpile with conveyance at bottom
207
Bayer process
1. Al2O3 dissolve is in molten cryolite
2. Carbon anodes electrolytically collect O2 ions
3. Molten Al is left
208
Gangue Mineral for Lead zinc complex
Siderite
