zinc extraction and applications

1. Made by :
Riya Jajodia (R2402
Srishti Bhatt
(R240215024)

2. PHYSICAL PROPERTIES OF ZINC
 Crystal structure HCP
 Density (g.cm-3) 7.14
 Atomic weight 65.39
 Atomic number 30
 Melting point (◦C) 419.6
 Boiling point (◦C) 906

5. Zinc coating is mostly used as
sacrificial metal to stop
corrosion. Since it has higher
reactivity, it looses electron
faster and hence corrodes
saving the main material.
Because HIGH REACTIVITY and
LOW MELTING POINT , Zn is
NOT used to coat electric wires
as it gives low life to electric
wires.
Galvanization
Diecasting
Brass & Bronzde
Rolled Zn
Chemicals
Misc
GALVANISATION

6. DIE CASTING
HAS LOW Melting point
Can be easily melted to make
various dies
Since M.P is low, less thermal shock
Hence long life
Galvanization
Diecasting
Brass & Bronzde
Rolled Zn
Chemicals
Misc

7. Zinc Dies

8. ROLLED ZINC
 Rolled Zinc is produced as sheets,
strips, rod and wire, in many
composition and alloying as per
requirements.
Galvanization
Diecasting
Brass & Bronzde
Rolled Zn
Chemicals
Misc

10. Zinc Chemicals

11. AGRICULTURE
ZINC FERTILLIZERS
 Zinc Deficiency  low
chlorophyll

12. JELLYFISH STING CURE
 Tentacles touch human skin
 Venom released causes cell to rupture.
Can be fatal !
WHY?
 Before cell rupture, K is released. Sudden
increase of K in bloodstream can cause heart
attack.

13. CURRENT CURE :
URINATING ON THE STUNG AREA
BOX MEDICINES
New CURE
Zinc compound, zinc glutamate
*RESEARCH
going on

14. HUMAN BODY
 Zinc is responsible for various reactions in our body.
 It plays a vital role in cell division, cell growth, wound healing, breakdown of
carbs, enzyme production.
IS A MAJOR KEY IN
FERTILLIZATION

16. The moment a sperm enters an egg , Zinc Sparks
occur.
Zinc starts forming a layer on the surface of the
fertilized egg preventing any other sperm to enter
the egg
Only happens in zinc rich egg

19. This could be very beneficial for IVF !
IF one can measure the Zn spark during
fertilization, they can know which fertilized
egg will develop into an healthy embryo !

20. SUNSCREEN
 Zinc oxide is major component of sunscreens
 It reflects the uv rays from sunlight protecting our skin
 Better than tio2
 Nano zinc oxides are also used.

22. Sphalerite (ZnS)
Zincite (ZnO)
Franklinite [ZnO(Fe,Mn)2O3 ]
Calamine[Zn2(OH)2SiO3 ]
Smithsone (ZnCO3 )
Zn Ores Zn

23. Mining
Crushing
Roasting
Pyro/hydro
metallurgy
process

24. ROASTING
oxidizing zinc sulfide concentrates at high temperatures into an impure zinc oxide,
called “Zinc Calcine”. The chemical reactions taking place during the process
are:
2ZnS + 3o2 => 2ZnO + 2So2
2So2 + O2=> 2So3
Approximately 90% of zinc in concentrates are oxidized to zinc oxide, but at the roasting
temperatures around 10% of the zinc reacts with the iron impurities of the zinc sulfide concentrates
to form zinc ferrite .

25. HYDRO- METALLURGICAL
PROCESSES
Electrolysis ( Roast Leach
Electrowin)
PYRO-
METALLURGICAL
PROCESSES
Horizontal Retort
Vertical Retort
Electro-
thermal
Imperial Smelting

26. 1
• LEACHING
• ZnO + So3ZnSo4
2
• PURIFICATION
• Impurities  Co, Cd, Cu, Ni
3
• ELECTROWINNING

27. ELECTROwinning
Zn is extracted from purified ZnSo4 solution by electrowinning.
Electric current is passed through the solution in a series of cells.
Zn deposit on the cathodes and o2 form at anodes.
Sulfuric acid is also formed in the process and reused in the
leaching process. Every 24 to 48 hours, each cell is shut down, the
zinc-coated cathodes are removed and rinsed, and the zinc is
mechanically stripped from the Al plates.

28.  Electrolytic zinc smelters contain as many as several hundred cells. A portion
of the electrical energy is converted into heat, which increases the
temperature of the electrolyte. Electrolytic cells operate at temperature
ranges from 30 to 35 °C (86 to 95 °F) and at atmospheric pressure.
 A portion of the electrolyte is continuously circulated through the cooling
towers both to cool and concentrate the electrolyte through evaporation of
water. The cooled and concentrated electrolyte is then recycled to the cells.
This process accounts for approximately one-third of all the energy usage
when smelting zinc.

30. St. Joseph Mineral Company (electrothermic) process
Working: The process begins with a sintering operation.
 The sinter : roaster calcine + EAF calcine
is loaded onto a gate type conveyor. combustions gasses are pumped through the sinter. The carbon in the combustion gases
react with some the impurities, such as lead, cadmium, and halides.
impurities filtration bags.
The sinter after this process, called product sinter, usually (48% zinc, 8% iron, 5% aluminum, 4% silicon, 2.5% calcium)
The sinter product is then charged with coke into an electric retort furnace.
A pair of graphite electrodes from the top and bottom furnace produce current flow through the mixture.
ZnO+Co Zn(Vapour)+Co2

31.  The coke provides electrical resistance to the mixture in order to heat the mixture to 1,400 °C (2,550 °F) and
produce carbon monoxide.
 The zinc vapour and carbon dioxide pass to a vacuum condenser, where zinc is recovered by bubbling through a
molten zinc bath. Over 95% of the zinc vapour leaving the retort is condensed to liquid zinc.
 The carbon dioxide is regenerated with carbon, and the carbon monoxide is recycled back to the retort furnace.

Advantages: It is able to smelt a wide variety of zinc-bearing materials, including electric arc furnace dust.
 Disadvantages: It is less efficient than the electrolysis process.

32. IMPERIAL SMELTING PROCESS (ISP) 8-10%
.
Working: The process consists of basic two operations namely; sintering and blast
furnace smelting of sintered lumps to extract lead and zinc simultaneously.
The process starts by charging solid sinter and heated coke into the top of the
blast furnace. Preheated air at 190 to 1,050 °C (370 to 1,920 °F) is blown into the
bottom of the furnace. Zinc vapour and sulfides leave through the top and enter
the condenser. Slag and lead collect at the bottom of the furnace and are tapped
off regularly. The zinc is scrubbed from the vapour in the condenser via liquid lead.
The liquid zinc is separated from the lead in the cooling circuit.
Reaction: C + 1/2 O 2 = CO
C + O 2 = CO 2
CO 2 + C = 2CO
ZnO + CO = Zn + CO 2

33. Belgian-type horizontal retort process
This process was the main process used in Britain from the mid-19th
century until 1951.
 Disadvantages: The process was very inefficient as it was designed
as a small scale batch operation..

34. NEW JERSEY ZINC
CONTINUOUS VERTICAL
RETORT
This processes peaked in 1960, when 5% of the world production was done by this process.
Working: This process begins by roasting concentrates that are mixed with coal and briquetted in
two stages. The briquettes are then heated in a autogenous coker at 700 °C (1,292 °F) and then
charged into the retort.
There are three reasons to briquette the calcine:
 To ensure free downward movement of the charge.
 To permit heat transfer across a practical size cross-section.
 To allow adequate porosity for the passage of reduced zinc vapor to the top of the retort.
The reduced zinc vapor that is collected at the top of the retort is then condensed to a liquid.

35. ZINC ALLOYS
WROUGHT ALLOY
- Zn-Pb alloys
- Zn-Cd alloys
- Zn-Cu alloys
CAST ALLOY
- Conventional zinc
casting alloys (4% Al)
-Zn-Al (ZA) casting
alloys

36. Casting Alloys
• used for sand, permanent mold, plaster mold, shell mold, and investment
casting.
• mechanical aspects of these alloys make them attractive substitutes for cast
iron alloys (better corrosion resistance and machinability) and copper alloys
(lower cost) in structural and pressure-tight applications.
• zinc’s low melting point allows for lower energy requirements during casting.
Wrought Alloys
• obtained as various shapes and exhibit good resistance to corrosion in many
types of service.
• has chemical characteristics particularly adapted to certain uses, such as dry
batteries.
• Wrought zinc is easily machined using standard methods and tools, but if it is
necessary to machine zinc containing very coarse grains, the metal should be
heated to a temperature between 70-100°C in order to avoid cleavage of
crystals.

37. The role of alloying elements in conventional zinc
casting alloys and mechanical properties
The role of alloying elements
• Al is added for strengthening, reducing grain size, improving fluidity
(castability) and minimising the attack of the molten zinc alloy on the iron and
steel in the casting equipment.
• Mg is added in small amount (0.01-0.3%) to prevent intergranular corrosion
due to the presence of Pb, Cd and Sn impurities. But excessive amount lowers
fluidity and promotes hot cracking -> reduce elongation. (Pb < 0.003% and Sn
< 0.001% .
•Cu minimizes effects of impurities, improve strength and hardness. (Cu < 1% -
> higher amounts lead to reduced toughness, embrittlement).
Mechanical properties
• Tensile strength : 220-440 MPa
• Yield strength : 210-380 Mpa
• Elongation : 1-10%

38. Engineering design with zinc alloys Applications
• Used for automobile parts such as handles, locks mechanical and electrical
components.
• Body hardware, light fittings, instruments.
• Galvanic coating on steels. The alloys are
die cast, permanent mould cast and sand
cast.

39. Advantages of zinc alloys
1) Ability of zinc to die cast at high productivity rates due to zinc’s relatively low melting point (419oC).
2) Ability to produce near-net shapes of intricate designs with close dimensional tolerance and good
surface finishes.
3) Zinc die castings can be machined, bent, swaged or coined for finishing.
4) Zinc die castings can be riveted, welded, and soldered in assembly operations.
5) Relatively good atmospheric corrosion resistance, especially in Cr solution (forming surface passive
film).
6) Sufficient strength for some applications.
7) Cost of Zn is competitive with Al and Cu alloys for many applications.

40. THANK YOU