Glass And Ceramics Processes Presentation, Study Guides, Projects, Research of Chemical Processes

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GLASS

Glass

• Glass, an inorganic solid material that is usually transparent or translucent as well as hard, brittle, and impervious to the natural elements.
• Glass has been made into practical and decorative objects since ancient times, and it is still very important in applications as disparate as building construction, housewares, and telecommunications.

Glass is made from natural and abundant raw materials (silica sand, soda ash and limestone) that are melted at very high temperature to form a new material: glass. RAW MATERIALS Silica Sand Soda Ash Limestone

HISTORY OF GLASS

• 7000 to 3000 B.C. The story of glass does not even begin in Mesopotamia, where master craftsman discovered how to make glass in the third millennium BC.
• 1500 B.C. In about 1500 BC, the Egyptians produced the first hollow glass containers, which they used for ointments and oils. The oldest dated glass object can be seen in the State Collection of Egyptian Art in Munich: a dainty goblet made of pale blue glass.
• 658 B.C. The library of the Assyrian king Ashurbanipal contains the first recorded recipe for making glass: "Take 60 parts sand, 180 parts ash from sea plants and five parts chalk.“
• 100 B.C. In about 100 BC, a technological revolution occurred at a glassmaker's hut on the Syrian coast which is the invention of blowpipe.

• 1925

In 1925 , the engineers Ingle and Smith registered the

patent for the IS machine. This produces hollow glass using

the blow-and-blow technique, a production method that is

still used to this day.

• Present age

In the second half of the 20 th century, it was primarily the

introduction of electronically controlled machines that

increased the production volume for glass manufacturers.

VARIETIES OF GLASS

• SODALIME OR SOFT GLASS
  • About 90 % of all glass is soda-lime glass made with silica

(sand), calcium carbonate and soda ash.

• The approximate composition is Na 2 CO 3 .CaO. 6 SiO 2.
• POTASH LIME OR HARD GLASS
• Potash lime glass is made with silica (sand), calcium

carbonate and potassium carbonate.

• The approximate composition is K 2 CO 3 .CaO. 6 SiO 2.

• TOUGHED GLASS

• A type of safety glass which is prepared to increase the strength of normal glass.
• Also known as “tempered glass”.
• WIRED GLASS
• Wired glass does not fall apart into splinters when it breaks and if fire resistant. It is made by fusing wire in between the two glass layers.
• PHOTOSENSITIVE GLASS
• These are glasses by which a colored picture may be developed by exposing the glass to black and white negative in ultra violet light. The appropriate proportions of potash-alumina glass, mixed with LiSO 3 , cerium and silver salts have also been used as photosensitive glass.

BIOACTIVE GLASSES

• A group of surface reactive glass-ceramic bio-materials and include the original bio active glass, bio glass. RECENT DEVELOPMENTS

• MELTING IN FURNACE:
  • The batch is melted either in a pot furnace or in a tank furnace. The heating is continued until the evolution of carbon dioxide, oxygen, sulphur dioxide and other gases stops.
• FABRICATION:
  • The molten glass is given suitable shape or form in this stage.
• Blowing:
  • For this purpose, a blow-pipe is used. Its diameter is about 12 mm and its length is about 1. 80 m.
• Casting:
  • The molten glass is poured in moulds and it is allowed to cool down slowly.
• Drawing: This process consists in simply pulling the molten glass either by hand or by mechanical equipment.

GLASS PROCESS MANUFACTURING

• Pressing:
  • In this process, the molten glass is pressed into mould.
• Rolling:
  • There are two methods of rolling. In one method, the molten mass of glass is passed between heavy iron rollers and flat glass plate of uniform thickness is obtained. In another method, the molten mass of glass is poured on a flat iron casting table and it is then turned flat with the aid of a heavy iron roller.
• Spinning:
  • In this process, the molten glass is spun at high speed by a machine to form very fine glass fibers.

GLASS PROCESS MANUFACTURING

GLASS PROCESS MANUFACTURING

• QUALITY CONTROL
  • Every single pack is subjected to strict automated quality controls. Defective packaging is melted again in the furnace.
• PACKING AND SHIPPING
  • The packages are palletized and hermetically sealed so that they reach the customer in the best possible condition.

CERAMICS

Venus of Dolni Vestonice

• The oldest known ceramic artifact is dated early 28 , 000 BCE