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Glass Industries


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This presentation enables u to know What is meant by glass,properties of glass,glass manufacture and finally types of glass we use daily in our daily life.

This presentation enables u to know What is meant by glass,properties of glass,glass manufacture and finally types of glass we use daily in our daily life.

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  • 1. What is Glass ?Glass is a substance which is made by high fluxes which isheated to high temperature and its is completely vitrifiedproduct.Glass is an amorphous (non-crystalline) solid material.Glasses aretypically brittle and optically transparent.The following are the properties that are exhibited by theglass1. Capacity to absorb different colors without effecting transparency2. Hardness3. Chemically inert4. High refractive index5. High dispersion6. High refractive index7. Transparent and translucent8. Low thermal conductivity9. Electrical insulator10. Brittle
  • 2. Physical properties of glass :Amorphous : In condensed matter physics, an amorphous (fromthe Greek a, without, morphe, shape, form) or non-crystallinesolid is a solid that lacks the long-range order characteristic of acrystal.Brittleness : A material is brittle if, when subjected to stress, itbreaks without significant deformation (strain). Brittle materialsabsorb relatively little energy prior to fracture, even those ofhigh strength. Breaking is often accompanied by a snappingsound
  • 3. Difference between brittle material and ductile material : Graph comparing stress-strain curves for brittle and ductile materials
  • 4. Transparency and translucence : In the field of optics,transparency (also called pellucidity or diaphaneity) is thephysical property of allowing light to pass through a material;translucency (also called translucence or translucidity )onlyallows light to pass through diffusely. Capacity to absorb different colours without affecting transparencyDispersion : In optics, dispersion is the phenomenon inwhich thephase velocity of a wave depends on its frequency, oralternatively when the group velocity depends on the
  • 5. In a prism, material dispersion (a wavelength-dependent refractiveindex) causes different colors to refract at different angles, splittingwhite light into a rainbow.
  • 6. Vitrification : It is a word (from Latin vitreum, "glass" via Frenchvitrifier) is the transformation of a substance into a glass.Usually, it is achieved by rapidly cooling a liquid through theglass transition. Certain chemical reactions also result inglasses. An important application is the vitrification of anantifreeze-like liquid in cryopreservation. A vitirfied glass cook top
  • 7. Glass colouring : Glass coloring and color marking may beobtained by addition of coloring ions, by precipitation ofnanometer sized colloids (so-called striking glasses such as"ruby gold" or red "selenium ruby"), by colored inclusions (as inmilk glass and smoked glass), by light scattering (as in phaseseparated glass), by dichroic coatings or by colored coatings.
  • 8. The formula of the glassx R2O y MO 6Sio2WhereR=Mono valent ions such as Na KM=Bi valent ions such as Ca Zn MgRaw Materials used for glass1. Sand2. Soda Ash Forms basic part of glass3. Sodium nitrate Accelerates melting4. Cao Forms basic part of glass5. Silica Forms acidic part of glass6. Barium Sulphate To remove impurities in the form of the Scum7. Feldspar Retards de vitrification8. Potassium Oxide Used as softening agent9. Borax Increase hardness or refractive index10. Boric Oxide Improves chemical or corrosive resistivity
  • 9. 13. Lead Oxide Increases insulation14. Selenium Used as DecolorizerColoring Agents :1. Cadmium Oxide Red color2. Copper Oxide Ruby red3. Titanium Oxide Light yellow4. Cobalt Oxide Deep blue5. Cuprous Oxide Greenish Blue6. Chromium Oxide Emerald green7. Manganese Oxide BlackWhile fused quartz (primarily composed of SiO2) is used for somespecial applications, it is not very common due to its high glasstransition temperature of over 1200 °C (2192 °F).Normally, other substances are added to simplify processing. One issodium carbonate (Na2CO3), which lowers the glass transitiontemperature.However, the soda makes the glass water soluble, which is usuallyundesirable, so lime (calcium oxide (CaO), generally obtained fromlimestone), some magnesium oxide (MgO) and aluminum oxide
  • 10. (Al2O3) are added to provide for a better chemical durability.The resulting glass contains about 70 to 74% silica by weight and iscalled a soda-lime glass.Soda-lime glasses account for about 90% of manufactured glass. Quartz sand (silica) is the main raw material in commercial glass production
  • 11. Glass is an amorphous solid. It exhibits an atomic structureclose to that observed in the super cooled liquid phase butdisplays all the mechanical properties of a solid.The amorphous structure of glassy Silica (SiO2) in twodimensions. No long range order is present, however there islocal ordering withrespect to the tetrahedral arrangement of Oxygen
  • 12. Major steps in glass manufacture1.Selection of raw materials2.Size reduction3.Melting of Raw materials4.Shaping5.AnealingDouble click on the diagram to view full screen
  • 13. Process :Based on the type of the glass suitable glass manufacture materialsare selected . Raw materials are reduced to 100-200 Mesh bycrushing and grinding. Raw materials are now subjected to melting inPot furnace or monkey furnace.Pot furnace :For special glasses like optical glass raw materials are melted in pot(monkey shaped pots) made of ceramic material capacities varyingfrom 1-2 tons.Tank Furnace :Molten glass is obtained by melting the raw materials in 150-200 toncapacity regenerative tank furnace. During melting of raw materialsvarious reactions occur at various temperatures .Reactions :100 C Surface moisture loss500 C Body moisture loss500-600 C Na2CO3 ---------> Na2O + CO2
  • 14. Pb3O4 --------> 3PbO + [O]600-800 C PbO + SiO2 ---------> PbSiO2 Na2SO4 + 2C ---------> Na2S + 2CO2 K2CO3 ---------> K2O+ CO2 K2O + SiO2 ---------> K2SiO3800- 900 C Na2SO4 ---------> Na2O +SO3 Na2S + SO3 ----------> Na2O+SO2+[S] Na2O+SiO2 ----------> Na2SiO3900 - 960 C CaCO3 ----------> CaO + CO21010 C CaO+SiO2 ----------> CaSiO31120 - 1400 C Vitrification
  • 15. Shaping :Completely vitrified glass from tank furnace is shaped on thetype of the finished product.Shaping Methods :1. Colburn Horizontal drawing2. Float/Asahi Vertical drawing3. Pilkington Glass float over tin4. ForcaultParison mould process : Glass products produced / shaped by this process are narrow neck and wide neck products. Gob of glass is transferred to parison mould. Plunger is lowered as a result parison is obtained and transferred to blowing mode.
  • 16. Shaping of narrow / wide neck product : Transfer glass gob to parison mould blow air fromtop where gob rests on narrow neck. Air is blown from bottomuntil it should fill the neck. Obtain parison after Demoulding .Transfer the parison to the narrow neck blowing mould. Blow airfrom the top. Demould to obtain narrow neck product. The above shaping process is a batch processand used for continuous manufacture o the products. It consistsof two rotating tables. One table is mounted with parisonmoulds and the other with the blowing moulds. As a result theshaping operation is carried in a continuous process andincreases the productivity.
  • 17. Shaping of window glass or plate glass : Molten glass from tank furnace is shaped fromplate glass by following method. Molten glass at 980 C is transferred to arectangular tank line with refractory bricks. A refractory brickwith a slot in center called as debituse is made to float overmolten glass. Molten glass emerges in the form of tonguethrough the slot which is hold firmly by metallic baits. This isfollowed by continuous drawing of glass through the slot by thewater cooled rollers cooling the external surface of the glassleaving the core of glass under stresses. The glass which isdrawn horizontally or vertically in next stage as per following.Colburn :Glass is drawn horizontally producing 1-2 mm thick windowglass.Asahi :Glass is drawn vertically to produce 0.05 to 0.2 mm. It is the
  • 18. Forcault :Similar to colburn process (horizontal)Pilkington :In this process molten glass is allowed to flow over a molten tinbecause of close melting point range. After cooling hardenedglass floating over molten tin is cut into desired specification.Annealing :During roiling and also cooling only surface of glass coolsleaving core of glass under heavy stresses which make glasshighly brittle. Hence it is subjected to annealing process in aannealing tunnel which is horizontal or vertical wheretemperature of core of glass is brought to ambidenttemperature and as the entire length of annealing tunnelincreases then the temperature decreases . This variation canbe given by the following graph given below.
  • 19. Glass making in laboratory :
  • 20. Types of Glass :1. Quartz glass : When silicon dioxide SiO2 is cooled rapidly enough, it does not crystallize but solidifies as a glass. The glass transition temperature of pure SiO2 is about 1600 K (1330 °C or 2420 °F). Like most of the crystalline polymorphs the local atomic structure in pure silica glass is regular tetra hedra of oxygen atoms around silicon atoms forming quartz glass.Optical fibers made from quartzglass play a major role incommunication.
  • 21. 2. Soda-lime glass : It is also called soda-lime-silica glass, isthe most prevalent type of glass, used for windowpanes, andglasscontainers (bottles and jars) for beverages, food, and somecommodity items. Glass bake ware is often made of temperedsoda-lime glass. Soda-lime glass is prepared by melting theraw materials, such as sodium carbonate (soda), lime,dolomite, silicon dioxide (silica),aluminum oxide (alumina),and small quantities of fining agents(e.g., sodium sulfate,sodium chloride) in a glass furnace at temperatures locally upto 1675 °C.
  • 22. 3. Bullet-resistant glass : It is a type of strong but opticallytransparent material that is particularly resistant to beingpenetrated when struck by bullets, but is not completelyimpenetrable. It is usually made from a combination of two ormore types of glass, one hard and one soft. The softer layermakes the glass more elastic, so it can flex instead of shatter.The index of refraction for both of the glasses used in thebulletproof layers must be almost the same to keep the glasstransparent and allow a clear view (not distorted) through theglass. Bulletproof glass varies in thickness from three-quarterinch to three inches.
  • 23. 4. Flat glass : It is a sheet glass, or plate glass is a type of glass,initiallyproduced in plane form, commonly used for windows, glassdoors,transparent walls, and windshields. For modern architecturalandautomotive applications, the flat glass is sometimes bent afterproduction of the plane sheet. Most flat glass is soda-limeglass, produced by Forcault process.
  • 24. 5. Fiberglass : Fiberglass is a lightweight, extremely strong, androbust material. Although strength properties are somewhatlower than carbon fiber and it is less stiff, the material istypically far less brittle, and the raw materials are much lessexpensive. Its bulk strength and weight properties are also veryfavorable when compared to metals, and it can be easily formedusing molding processes. The plastic matrix may be epoxy, athermosetting plastic (most often polyester or vinylester) orthermoplastic. Common uses of fiber glass include boats,automobiles, baths, hot tubs, water tanks, roofing, pipes,cladding and external door skins.Storage tanks can be made offiberglass with capacities upto about 300 tones. Thesmaller tanks can be madewith chopped strand mat castover a thermoplastic innertank which acts as a preformduring construction.
  • 25. 6.Studio glass : Studio glass or glass sculpture is the modern use ofglass as an artistic medium to produce sculptures or three-dimensionalartworks. Specific approaches include working glass at roomtemperature cold working, stained glass, working glass in atorch flame (lampworking), glass bead making, glass casting,glass fusing, and,most notably, glass blowing.
  • 26. 7.Lead glass : It is a variety of glass in which lead replaces thecalcium content of a typical potash glass.[1] Lead glasscontains typically 18–40 weight% lead(II) oxide (PbO), whilemodern lead crystal, historically also known as flint glass dueto the original silica source, contains a minimum of 24%PbO.[2] Lead glass is desirable owing to its decorativeproperties. Glass beads made up of lead glass
  • 27. 8. Flint glass : It is a optical glass that has relatively high refractiveindex and low Abbe number. Flint glasses are arbitrarily definedas having an Abbe number of 50 to 55 or less. The currentlyknown flint glasses have refractive indices ranging between1.45 and 2.00. A concave lens of flint glass is commonlycombined with a convex lens of crown glass to produce anachromatic doublet lens because of their compensating opticalproperties, which reduces chromatic aberration (color defects).Flint glass can be fashioned into rhinestones which are used asdiamond stimulants.An achromatic doublet,which combines crownglass and flint glass.
  • 28. 9.Float glass : I Glass is a sheet of glass made by floating moltenglass on a bed of molten metal, typically tin, although lead andvarious low melting point alloys were used in the past. Thismethod gives the sheet uniform thickness and very flatsurfaces. Modern windows are made from float glass. Mostfloat glass is soda-lime glass, but relatively minor quantities ofspecialty borosilicate and flat panel display glass are alsoproduced using the float glass process. The float glass processis also known as the Pilkington process,
  • 29. 10. Chalcogenide glass : It is a glass containing one or more chalcogenide elements. These are Group 16 in the periodic table e.g. sulfur, selenium or tellurium. Such glasses are covalently bonded materials and may be classified as network solids. In effect, the entire glass matrix acts like an infinitely bonded molecule. The classical chalcogenide glasses are strong glass-formers (mainly sulphur based ones) such as systems As-S, Ge-S possess glasses within large concentration regions.A CD-RW (CD).Amorphous chalcogenidematerials form the basisof re-writable CD andDVD solid-state memorytechnology....
  • 30. It’s a C.B.I.T production @ Cbit 2011