The document provides an overview of the glass industry, detailing the composition, manufacturing process, types, and applications of various glass products. It also discusses safety glasses, photochromic lenses, and the state of glass manufacturing in Pakistan. Key components include raw materials, chemical reactions involved in production, and the benefits of cullet in melting processes.

1. GLASS INDUSTRY
RABIA AZIZ BS-III Chemistry
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2. CONTENTS
 Glass
 Safety glasses
 Photo chromic glasses
 Photographic lenses
 Glass Industries In Pakistan
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3. GLASS
 Super cooled liquid
 Non-Crystalline: Molecules are arranged in random
positions that’s why glass not have sharp melting
point. On heating it becomes more and more plastic
in nature.
 Silicon Dioxide is the main component of glass.
 Transparent
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4. STRUCTURE:
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5.  Raw Material:
 Silica
 Lime stone (CaCO3)
 Soda Ash (Na2CO3)
 Chemistry involve in Glass:
 Na2CO3 + SiO2 → Na2SiO3 + CO2
 CaCO3 + SiO2 → CaSiO3+ CO2
or
 Na2CO3 + CaCO3 + 6SiO2 → 2 CO2 +
Na2O.CaO.6SiO2 (glass)
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6.  Manufacture Process:
 Raw material --- Batch (Powder) → Batch + Cullet
(broken glass)---mix → Melt → Shape → Annealing
 Cullet : use for Speeds up melting
 Annealing: Heat (glass) and allow it to cool slowly,
in order to remove internal stresses and toughen it.
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7.  Types of Glasses:
1. Soft glasses, use → windows, bottles
2. Hard glasses, use → test tube (acid resistance)
3. Pyrex glasses, use → laboratory equipment
4. Flint glasses, use → eye glasses
5. Quartz glasses, use → optical instrument,
electrical bulb
6. Borosilicate glasses, use → china dish, baking
dish, pipes
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8. SOFT GLASS
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9. HARD GLASS
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10. PYREX GLASS
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11. FLINT GLASS
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12. QUARTZ GLASS
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13. BOROSILICATE GLASS
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14. Etching:
 The techniques of creating art on the surface of
glass by applying acidic, caustic, or abrasive
substances.
 Example: Hydrofluoric acid is used to make designs
on glass.
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15.  Coloration:
 Iron oxide → bluish green
 Iron oxide + Cr → dark green
 Iron oxide + S + C → amber (orange red)
 B + S → blue
 Mn → amethyst (moderate purple)
 Co (0.025- 0.1) → blue
 Cu → tortoise
 Ni
 small amount → Blue
 Moderate → Violet
 High → Black
 Ti → use for sharp and bright the color
 Ur → use for shine
 Cd (0.1-2) + S → deep yellow
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16. SAFETY GLASSES
 Made up by sandwich plastic between two glasses
 Use → in Laboratory, welding, airplanes
 Plastic → Vinyl butyrol + methyl methacrylate
 Process:
I. Cutting
II. Inspection
III. Washed
IV. Adhesive
V. Temperature and pressure
VI. Finishing
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17.  Classes:
1. Spectacles
2. Goggles
3. Welding helmet
4. Welding hand shield
5. Face shield
6. Non-rigid hoods
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18.  Photo chromic glasses (eye glass):
 They are optical lenses.
 They darken on exposure to sunlight.
 Halide salt are embedded in photo chromic glasses.
o Photographic lenses:
 It is an optical lensor assembly of lenses used in
conjunction with a camera body and mechanism to
make images of objects either on photographic film
or on other media capable of storing an image
chemically or electronically.
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19. GLASS INDUSTRIES IN PAKISTAN
 In Pakistan there are about 25 glass industries
which are producing about 75,000 tons of glass per
year.
 Names of some glass producing factories
 Indus Glass Work, Hyderabad
 Toyo Nasik Glass Factory, Lahore
 Khawaja Glass Work, KPK
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