GLASS

Question 1

what is the major component of glass?

Answer 1

silicon (silicon dioxide)

Question 2

define glass

Answer 2

amorphous, inorganic product of fusion that has been cooled to a rigid condition without crystallizing

Question 3

where can silicon be found?

Answer 3

as silica or silicate

• quartz
• sand
• cristobalite
• feldspar
• kaolinite

Question 4

geometric structure of a silica molecule?

Answer 4

tetrahedral

Question 5

describe silica’s physical properties

Answer 5

• high melting point
• high toughness
• low/null transparency
• poor inertness

Question 6

what is silica’s chemical formula?

Answer 6

SiO2

Question 7

why can’t you fold glass?

Answer 7

chemical bonding

Question 8

what does it mean to have an amorphous structure?

Answer 8

molecular units have disordered arrangement but sufficient cohesion to produce mechanical rigidty

Question 9

how is an amorphous structure created?

Answer 9

introducing other elements like potassium, magnesium, sodium, calcium, etc

Question 10

what is the basic formula of glass?

Answer 10

• silica (SiO2)
• limestone (CaO)
• soda ash (Na2O)
• alumina (Al2O3)
• cullet (recycled glass)

Question 11

network formers of glass

Answer 11

SiO2

Question 12

network modifiers of glass

Answer 12

Na2CO3 –> Na2O + CO2

Question 13

stabilizers in glass

Answer 13

CaCO3 –> CaO + CO2

Question 14

what’s the point of using cullet?

Answer 14

reduces cost/energy

Question 15

formers

Answer 15

• silica sand
• boron oxide
• cullet

Question 16

fluxes

Answer 16

• sodium carbonate

- potassium carbonate

Question 17

stabilisers

Answer 17

• calcium carbonate
• magnesium carbonate
• barium carbonate

Question 18

fining agent

Answer 18

• sodium sulphate

Question 19

colourant, bleaching

Answer 19

• metal oxides

Question 20

what colors can you turn glass?

Answer 20

• amber (carbon & sulphur compounds)
• blue (cobalt oxide)
• green (ferrous sulfate, chromium oxide)
• yellow (ferric oxide, antimony oxide)
• blue-green (cobalt oxide, chromium oxide)
• opal (calcium oxide)

Question 21

steps to glass production

Answer 21

• raw materials
• mixing
• melting
• forming
• glass products

Question 22

how are metal impurities removed from the raw materials?

Answer 22

magnets

Question 23

80-90% of the heat flux is consumed at what step of glass production?

Answer 23

batch melting (melting and sand dissolution)

Question 24

what is primary fining?

Answer 24

step that removes metals

Question 25

what is secondary fining?

Answer 25

second removal of impurities

Question 26

temperature of batch input

Answer 26

25C

Question 27

temperature of batch melting

Answer 27

1200C

Question 28

temperature of sand grain dissolution

Answer 28

1400C

Question 29

temperature of fining

Answer 29

1500C

Question 30

temperature of fining

Answer 30

1500C

Question 31

temperature of refining and conditioning

Answer 31

1250C

Question 32

about ____ -____% of mass of normal soda-lime silica batches is transferred into volatile _____

Answer 32

14-20%; CO2

Question 33

fine cullet enables glass to foam at a (higher/lower) temperature and (longer/shorter) time than coarse cullet

Answer 33

lower, shorter

Question 34

how do you remove bubbles from glass?

Answer 34

fining of glass melt: use high temps and add Na2SO4 as a binding agent to generate new gases, making new bubbles. these will combine with the original bubbles and make it easier for them to ascend.

Question 35

larger bubbles take (longer/shorter) time to ascend

Answer 35

shorter