> Process
- Glass are made by heating mixtune that nearly always consist of silica call & dry powder or metallic oxides.
- Most glass are manufactun by a process in which raw-mateutials are converted at high temperature to a homogejeaus melts , that is then form in to an article.
- Raw mateutials are selecting acrourding the properties purity supply, cost etc .
- Silica sand is most common in goradiant all most type of glasses.
- limp-Stones is a sourvr of colcium soda ash is Source of Sadium and bore and Boutic acid is Source of borone.
- Broken gloss Usually termed as collected is used as a batch material to enhance glass melting and to resuce the amount of dust and other particular matter that aften a companies a batch mads exculsively from fresh raw-mateuial.
- Tipically 10 to 151% of glass batch is the comprised of collect.
- More efficient of operation as used in the container glass industries may required of purchas of collect forom flate glass compay or colloctors and distuributouis.
- Morden analytical techniques hve not only added glass produce but also unable suppiers of raw material to produce more consistance proloduct.
-Melling and fiing depends on the batch mate rial interacting where each other the proper types and proper.
- Ideally when the intimently mixed is changed in to the hot furnece series of melting in dissociation Volatarization and redox reaction ane takes-place between the material in a particulr order and particulaur temperature.
- In the continueous tank furnace four type of process occuuis like Melting, Refiming fining & homo-genzing .
- After homo-genizing whole mass cooled at 800°c in fabrication unit, where Shaped is done drawing pressing or blowing depending upon the Size of anticles.
- Finished the product and charged in to the anotheui furnace for anneling.
- Aneling is caunied out at about 500°C for 60 to 90 minutes.
- After anneling inspection and testing is done and then inspected material packed and dispatch while unpassed moteurial is rejectedd as collect which is recycle.
> Types Of Glass
-There are man five types of Glass
1) Soda-Lime Glass
- This type still Putovides most of the common, Colouiless transparent.
- This raw materials are the least experisive & they among the easiest to melt & Shape.
- Molten Soda-line glass are typically well using suited for windon glass sheet glass, Plate glass, comtainens such as bottles inexpensive table were etc.
-However their relatively low softening temperature & relatively low thermal shock resistance limits their high termp. usefulmess.
-These are easily attacked by strong alkalis.
2) Lead Glass
-Lead glass is essentially made by using lead oxide - pbo for fluxing & stahlbilizing the silica & the akali.
-very high Percemtage of lead oxide may be corporated for some extra dense oplical qlasses.
-Lead glaas are some what more
expensive but are easier to melt & shape.
-Lead glasses have greater rework ability.
- High lead content markedly inculegse the absouiption of x-rays & such glasses are used for Arotection agai16L x-rays & other radiation
-Costly Prisms & lenses are usually made of lead glass.
3) Borosilicate Glass
-In this type of glass melting pint of Silica is lowered by the addifon of boric & boron oxide
-This type of glass contins unusually Small amounts of alkalis & non or at the most 1% of calcium oxide.
-Silica content is signiticantly higher than that of Soda-lime glass lead glass.
-It may contain upto 3% of alumimium oxyda.
-These glasses are harder to melt & woork it has greater resistance to theurmal shock.
-These properties have made possible uses for these type of glasses as oven ware, theumally mechanically Strong laboratoy were, most of the Comman chemicols compoments for use in chemical industry & chemical laboratories.
4)Vycor Or 96% Silica Glass
-These type is made by a very different & new way of securing a desired composition.
-In first Stage , an alkali glass out borosilicate glass is melted & shaped in to desired anticle, but of about 14 % overisize dimensions.
-This anticle is heat -treated the glass of changes in to two inteuimingled glassy phases outer phase is high in alkalis & boron oxides.
-The other -inner phase is high in siljca ,contains about 96% silica & about 3% boroton oxides.
-In the second stage the soluble pphase Is leached out in hot mineral acids & the highen£r silica statuctume is left as a porous Sturuchure.
-The porous stucture is washed to remove the boric & is heated to about 1200°C.
- The glass article shrinks about 14% the structure becomes consolidated
-The 96% cilica glass -vycor has Such a stability & such high Sottening temp. ( about 1500°c) leboratory were crusibles furnare linings ultura Violet fillters & high fequency electutical insulations are typical application of the glass.
5) Silica qiass : (fused Silica)
-silica glass can be made by feeding a batch consisting silica sand of very high purity.
-Melting temp. of the batch is as high as that of silica crystal about 1750°Cll
-The molte glass is very highly viscous & it is very difficult to secure homogeneaity freedom from bubbles.
-very high viscosity at working temp. make fabrication difficuit l& limils the size & shapes of the arcticles
👌👌👌👌
ReplyDelete🙏🙏🙏
ReplyDeleteYou writing is always fabulous. This is third time I’ve read your blog and I find the information very useful.
ReplyDeleteschott filter glass