Glass manufacturing

2. Glass Industry
 Presented by:
• Amiza
Aqsa yousaf
 Presented to:
Dr. Jamil Anwar

3. CONTENTS
 Introduction
 Evolution of glass
 Manufacturing of glass
 Applications
 Glass industries in Pakistan
 Worldwide glass industries
 References

4. Introduction
What is a glass?
Glass is an amorphous, hard, brittle,
transparent, or translucent super cooled
liquid of infinite viscosity, obtained by
fusing a mixture of number of metallic
silicates or borates of sodium, potassium,
calcium and lead.
Glass possess no definite melting
points
It is non-crystalline
It softens over a temperature range
It can absorb, transmit and reflect light

5. History of Glass
Archaeological evidence shows that first glasses made by man arose in Egypt
and Eastern Mesopotamia (3500 B.C) . They were small artifacts like amulets
and pearls made with clay molds.
The first glass vessels also appeared in Egypt in 1500 B.C.
600 B.C, during this period first manuals on the glass manufacturing process
appear.
Sirios invented the blow pipe, revolutionizing the glass manufacturing process
and making it easier, faster, cheaper.

7. 1.Raw material
2.Batch
preparation
3.Melting in
furnace
4. Fabrication
5. Annealing
6. Finishing
Glass manufacturing
Steps involved in
manufacturing of glass

8. Raw material
Major ingredients
 Silica
 Soda ash or Soda
 Lime or limestone
Minor ingredients
• Potassium
carbonate
• Borax
• Feldspar
• Salt cake
• Arsenic oxide
• Cullet
• Lead(ii) oxide
• Coloring
materials
• Decolourants

9. Feldspar
As203
Borax or sodium tetraborate
decahydrate
PbO

10.  The raw materials, cullet and decolorizer are finely powdered in
grinding machines. These materials are accurately weighed in correct
proportions before they are mixed together. The mixing of these
materials is carried out in mixing machines until a uniform mixture is
obtained. Such a uniform mixture is known as the batch or frit and it
is taken for further process of melting in a furnace.
Batch preparation

11. The batch is melted either in a pot furnace or in a tank furnace. The two most
commonly furnace used for malting :
 Pot furnace
 Tank furnace
 Pot Furnace
• In this furnace, the pots are adopted as units. A pot is a vessel made of fire-clay.
• This process resembles the crucible steel process. These pots are placed in specially
prepared holes in the furnace.
• The charging and collecting doors are kept projecting outside so that raw materials
may be added and molten glass may be taken out conveniently. The pots are filled
with raw materials.
• The furnace is heated by means of producer gas. When the mass has melted down,
it is removed from the pot and it is taken for the next operation of fabrication.
• The melting of glass by pot furnace is an intermittent process. It is used to melt
small quantities of glass at a time or to prepare special types of glass.

13.  This furnace resembles the reverberatory furnace adopted for puddling of the
wrought-iron. The roof is given special shape to deflect the flames of heated gas.
The ports are provided for the entry of preheated producer gas.
 The doors are provided for charging and for taking out the molten glass.
 A bridge separates the tank into two unequal compartments.
 The batch is heated in large compartment and it contains somewhat impure glass.
It flows through opening of bridge into small compartment.
 The gall or floating impurities are collected at the top of large compartment. The
refractory lining is provided to the interior surface of tank. The tank is filled with
raw materials.
 The furnace is heated by allowing producer gas through ports. The charging of raw
materials and taking out of molten mass are simultaneous.
 This is a continuous process and it is adopted to melt large quantities of glass at a
time.
Tank furnace

15. Fabrication
1. Blowing:
Blow-pipe is used. Its diameter is about 12 mm and its length is about
1.80 m. One end of the blow-pipe is dipped in the molten mass of glass
and a lump of about 50 N weight is taken out. This lump of glass will
then lengthen to some extent by its own weight. The operator then blows
vigorously from other end of blow pipe. It can also be done with the help
of an air compressor. This blowing causes the molten mass to assume the
shape of a cylinder.
2. Casting:
The molten glass is poured in molds and it is allowed to cool down
slowly. The large pieces of glass of simple design can be prepared by
this method. It is also adopted to prepare mirrors, lenses

16. Shaping Pressing Spinning

17. Annealing Finishing
The glass articles, after being manufactured, are to
be cooled down slowly and gradually. This process
of slow and homogeneous cooling of glass articles
is known as the annealing of glass.
The articles obtained that are
subjected to a number of operations
such as cleaning, polishing,
grinding, rounding edges for
bringing them to a useable form.

18. Flow chart of glass manufacturing

19. Applications

20. Glass industries in Pakistan
• Gunj Glass Industry
• Ahmad Glass industries Private Limited
• Tariq Glass
• Babar Glass Industries
• Al-Fattah Aluminium & Glass Industries
• Ghani Glass
• SK Glass Industries
• Madina Glass Industries
• Hajvery Glass Industry
• Balochistan Glass Ltd (Unit-III)
• Jillani Glass
• Nowshera Sheet Glass Industries
• Omer Glass Industries
• Green Tech Glass Works Limited
• Muhammadi Glass Industries

21. Worldwide industries
5.6 5.7
11.5
14.6 14.9 15.1
9.3
0
2
4
6
8
10
12
14
16
guardian Industries
US
Nippon Sheet
glass Co
Corning
incorporated (US)
Kyocera Corp
(Japan)
Asahi Glass Co
(Japan)
PPG industries
(US)
Saint-Gobain
(France)
Cost in million $

22. Trade analysis
Tanzania US
10%
Bangladesh
20%
Afghanistan
70%
EXPORT VALUE

23. 23

24. REFERENCES
 Julian Henderson. (1985, November). The raw materials of early glass production (
Europe). Oxford Journal of Archaeology , 4(3), 267 - 291.
 Clarissa Justino de Lima, F. V. (2018, September). Advancements and Challenges in Glass
Concepts, Manufacturing and Applications. Applied Surface Science, 1(2), 1-10.
 Bekir Karasu, Deniz Şanoğlu, Ecenur Biryan. (2017, June). The Latest Developments in
Glass Science and Technology. Journal of Industrial and Engineering Chemistry , 4(2),
209-233.
 Savic Jelena, Danijela Djuric Mijovic, Veliborka Bogdanovic. ( 2013, January).
Architectural glass: Types, performance and legislation. Coordination Chemistry Reviews,
11(1), 35-45.