Batch particle size

Question 1

What is the effect of small particle sizes on mixing?

Answer 1

~ Initially, small particles permit more rapid rxn

Question 2

Where does CO2 escape during initial stages?

Answer 2

~ voids and channels

Question 3

What happens when CO2 can no longer freely evolve to the atmosphere?

Answer 3

~ occurs earlier with finer particle sizes

~ the rxn between silica and soda ash is suppressed

Question 4

What should the size of sand particles be for soda-lime glass?

Answer 4

~ <0.84mm (20 mesh screen)

Question 5

What should the size of sand particles be for more difficult melting borosilicate and aluminosilicate glasses?

Answer 5

~ <35mm mesh (0.5mm)

Question 6

What are the effects of alkali carbonates?

Answer 6

~ smaller than sand

~ allow alkali source to more evenly distribute itself on silica particles

Question 7

What are the effects of water additions?

Answer 7

~ indirectly accelerate melting via partial solution

~ more uniform deposition of fluxing agents on sand grains

Question 8

What’s the effect of excessive fines?

Answer 8

~ cause dusting in which airborne flux deposits on refractory surfaces or within the heat exchange checkerwork

Question 9

How do we eliminate dusting due to excessive fines?

Answer 9

~ ading 3-5wt% water to batch