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Principles of Metallurgy > Hydrometallurgy > Flashcards

Hydrometallurgy Flashcards

1
Q

the production of metals from
primary and secondary
metallurgical sources wherein
some of the chemical reactions
are carried out in aqueous
solutions at ambient temperature

A

Hydrometallurgy

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2
Q

Hydrometallurgy

Temp:

A

less than 300 degree C

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3
Q

Hydrometallurgy

Pressure

A

less than 2.07 MPa

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4
Q

ADVANTAGES of METALLURGY

A

a. have the ability to treat ores
b. may eliminate the requirements of waste
disposal
c. enables one to avoid emission of sulfur in
gaseous form

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5
Q

Advantages of Metallurgy

❖ minimum environmental impact; and
❖ no solid disposal problems

A

b. may eliminate the requirements of waste disposal

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5
Q

Advantages of Metallurgy

can improve the logistics and economics of
metal/mineral Extraction

A

a. have the ability to treat ores

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6
Q

Advantages of Metallurgy

❖ protects us from acid rain

A

c. enables one to avoid emission of sulfur in
gaseous form

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7
Q

most commonly used in GOLD hydro

A

Cyanidation

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8
Q

APPLICATIONS

90% production of ________

A

GOLD

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9
Q

80% production of ____

A

ZINC

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10
Q

APPLICATIONS

Production of ______

A

NICKEL AND COPPER

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10
Q

100% production of ____

A

ALUMINA

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11
Q

GENERAL STEPS

A

1 MINERAL BENEFICATION
2 ROASTING
3 LEACHING
4 SOLID/LIQUID SEPARATION
5 METAL/ MINERAL RECOVERY
6 SOLID/WASTE TREATMENT

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12
Q

What are the solid/waste treatment for sample?

A

Tailing Storage Facilities (TSF)

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13
Q

CHOOSING HYDROMETALLURGY

KADTONG 5 KABUOK YOT

A
  1. The amount of valuable mineral in the
    deposit
  2. Amenability of dissolving the valuable
    mineral using available solvents
  3. Presence of volatile toxic elements upon
    melting, i.e. As, Sb, Pb, Hg
  4. Cost of mining and bringing the ore to
    the surface
  5. Cost of milling and other pre-leaching
    treatments
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14
Q

+Process of dissolving valuable minerals or
metals from an ore or concentrate feed and
extracting the metals of interest into the
solution
+Feed may also be secondary sources
(scraps)
+Metallic ions are extracted in the leach
liquor, leaving a residue or gangue, free of
the valuable minerals

A

LEACHING

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15
Q

Choice of leaching methods depends on:

A

oOre grade
oLeaching kinetics
o Reagent consumption
oType of minerals
oSize of operation
o Capital and operating cost

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16
Q

TYPES OF LEACHING

A
  1. In-situ Leaching
  2. Dump Leaching
  3. Heap Leaching
  4. Percolation Leaching
  5. Agitation Leaching
  6. Pressure Leaching
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17
Q

APPLICATIONS AND TECHNIQUES SA IN-SITU LEACHING

LAST FOR???

A

APPLICATION
a. Near-surface low grade ore
b. deep seated high grade ore

TECHNIQUES
a. stope leaching
b. bore-hole solution

YEARS

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18
Q

APPLICATIONS AND TEACHNIQUES OF HEAP LEACHING

LAST FOR???

A

APPLICAITON
a. mined low grade ore
b.20 cm in diameter

TECHNIQUES
a. piled into heaps on impervious ground
b. solvent is allowed to permeate the heap

MONTHS

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18
Q

APPLCATION OF DUMP LEACHING

IT TAKES????

A

APPLICATION
a. stripped marginal deposition

TECHNIQUES
a. dumping in the foot or cliff
b. leaching agent is sprayed on it regularly

YEARS

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19
Q

Stirred tanks with or without air

A

AGITATION LEACHING

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20
Q

APPLICATIONS AND TECHNIQUES OF PERCOLATION LEACHING

LAST FOR?

A

APPLICATION
a. porous and sandy material
b. regular size at 5mm diameter

TECHNIQUES
a. does not need S/L separation
b. counter current leaching

WEEKS

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21
Q

APPLCIATIONS AND TECHNIQUES OF AGITATION LEACHING

LAST FOR?

A

APPLICATIONS
a. particles with 0.5 mm or less in diameter
b. slurry is introduced in the process
Counter Current

TECHNIQUES
a. Mechanical agitation
b. compressed air agitation
c. COmbined mechanical and compressed-air

DAYS

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22
Q

UNSAY GINAGAMIT SA PRESSURE LEACHING???

A

AUTOCLAVES

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23
Q

APPLICATIONS AND TECHNIQUES OF PRESSURE LEACHING

LAST FOR

A

APPLICATION
a. Minerals that are difficult to dissolve at STP

TECHNIQUES
a. mechanical agitation
b. compressed air agitation
c. combined mechanical and compressed-air

HOURS

24
Q

Choosing a solvent

5 ni sila

A
  1. Readily available
  2. Relatively cheap
  3. Selective in its dissolution
  4. Non-corrosive to construction
    materials
  5. Easily regenerated in the operation
25
Q

Choices of Solvents:

5 pud ni sila yot

A
  1. Aqueous salt solutions
  2. Chlorine water
  3. Water
  4. Bases
  5. Acids
26
Q

+Must be able to withstand
the pressure produced
from the evaporation of the
leaching agent since
operation is done above
the boiling temperature of
the leaching agent
* When under oxidizing atmospheres, it must be
able to withstand the additional pressure of
the heated air or gas

A

AUTOCLAVES

27
Q

OBJECTIVES SA ENRICHMENT PROCESS

A

produce smaller volume and richer pregnant solution

28
Q

METHODS

ION EXCHANGE

A

FUNCTIONALIZED RESIN

29
Q

METHODS

ADSORPTION

A

ACTIVATED CARBON

30
Q

METHODS

SOLVENT EXTRACTION

A

ORGANIC SOLUTION

31
Q

+the attached functional groups in the
resin undergo ionization to yield cations
(or anions of an anion exchange resin)
that selectively exchange with other
ions present in the solution in which the
resin is immersed

A

ION EXCHANGE METHOD

32
Q

allow gold to enrich during the process

A

ION EXCHANGE METHOD

33
Q

Dilute pregnant solution apply activated carbon so mabawasan si barren solution

A

SORPTION

33
Q

2 types of ADSORPTION METHOD

A

SORPTION

ELUTION

34
Q

stripping solution to get enriched pregnant solution

A

ELUTION

35
Q

+the solid carbonaceous material coal such as coal, wood, nut
shells, sugar, synthetic resins pyrolyzed at about 600oC in the
absence of air

A

CARBONIZATION

35
Q

The activated charcoal is a highly porous
carbon material made from coal, wood,
sugar, synthetic resins and nutshell

A

ACTIVATED CARBON

36
Q

+Carbon is exposed to steam or air for a limited time at temperatures between 400 and 800oC

A

ACTIVATION

37
Q

Properties of AC

A

+hard and abrasion resistant
+large surface area of 1200 m2/g
+high porosity at 0.7-0.8 cm3/g with 95%
macropores, then the remainder
comprises of meso- and micropores
+can act as reducing agents to metals in
salt solutions:

38
Q

Methods of Adsorption

A

+Carbon-in-Leach
+Carbon-in-Pulp
+Hybrid CIL-CIP method

39
Q

+carbon adsorbs the gold cyanide complex
from the slurry solution and is then removed by coarse screening
+6 tanks for leaching
+followed by 4-6 tanks for adsorption

A

Carbon-in-Pulp (CIP)

40
Q

+adsorption is limited in the first tank
+carbon loading is 20- 30% less
+often used for carbonaceous gold ores

A

Carbon-in-Leach

40
Q

+Similar to CIP process except that activated
carbon is used to extract gold from gold
cyanide solution streams, such as:
oHeap or dump leach solutions
oThickener overflow solutions
oUnclarified filtrates
oTailings reclaim solutions

A

Carbon-in-Solution

41
Q

+Modified CIP process
+leaching and adsorption occurs simultaneously
+– in a series of tanks, i.e. 6 tanks, the slurry is
introduced into the 1st tank while the AC is introduced in the last tank (counter-current)

A

Carbon-in-Leach (CIL)

42
Q

the loaded carbon is heated by a strong solution
of hot caustic and cyanide to reverse the
adsorption process and strip the carbon of gold

A

ELUTION or STRIPPING

42
Q
  • immediately maximizes the available surface
    area of the activated carbon
A

Carbon-in-Pulp

43
Q
  • pretreat loaded AC with strongly alkaline cyanide
    solution to convert calcium aurocyanide complex to sodium form
  • elution with deionized water at a temperature of
    95 – 125oC
A

DAVIDSON PROCESS

43
Q
  • loaded carbon is soaked in a 1.5 – 5% NaCN and
    0.5 – 2% NaOH solution for several hours at temp.
    greater than 90oC
  • Au and Ag is eluted with several bed volumes of hot distilled water
  • Reduced cycle time to 12 hrs
A

AARL – MODIFIED ZADRA

43
Q

(US Bureau of Mines, late
1960’s)
* insulated tank
* 90 – 93oC working temp
* 0.2% NaCN
* 1% NaOH
* flow rate: 1 bed vol/hr

A

ZADRA PROCESS

44
Q
  • uses an addition of 20% alchohol to the Zadra
    elution solution
  • elution is accomplished at 80oC for 6 – 8 hrs
  • the alcohol used are ethyl, methyl, and isopropyl
A

DRUNKEN ZADRA

45
Q
  • elution is carried at 145oC which simply
    means that elution is pressurized
  • elution time is 12 hours
A

PRESSURE ZADRA

46
Q

+a distributive reaction wherein the valuable metal is allowed to partition itself between two immiscible phases with the eventual establishment of equilibrium

A

Solvent Extraction

47
Q
  • are organic solvents in which the extractants are soluble
  • are immischible with water
  • constitue the bulk of the organic phase
  • are not able to extract metal ions but could influence behavior of extractants; inert component of the organic phase
A

Extractant + Carrier

48
Q
  • the formation from solution of a solid product
    as a result of dilution or of the addition of a
    reagent to the solution
A

Precipitation

49
Q

Factors affecting Precipitation

A

a) pH
b) temperature
c) complexing ions
d) concentration of the reactants

50
Q

factors sa precip

precipitates are only formed within a
certain pH range, since most of them are
redissolved outside this range

A

pH

51
Q

most precipitates are either more soluble in
hot than in cold solutions or decompose
when precipitation is carried out at high
temperatures

A

temperature

52
Q

the presence of a complexing ion in solution
prohibits the precipitation of the metal with
which it is complexed

A

complexing ions

53
Q

large crystals are obtained by precipitation
from dilute solutions; fine precipitates are
obtained from supersaturated solutions

A

d) concentration of the reactants

54
Q

+IONIC PRECIPITATION
+PRECIPITATION BY GASES
+PRECIPITATION BY METALS

A

Methods of Precipitation

Principles of Metallurgy (13 decks)

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