Corrosion profiles of fusion cast refractories in a glass tank

Question 1

What happens if the corrosion product rich glass is less dense than the bulk?

Answer 1

~ upward free convection

Question 2

What happens if the corrosion product rich glass is more dense than the bulk?

Answer 2

~ downward free convection

~ AZS refractory in soda lime glass

Question 3

What happens if the soluble corrosion products raise the liquid vapor surface tension of the glass?

Answer 3

~ fresh (lower surface tension) is drawn up to replace it, cutting a groove in the refractory at the glass line!

Question 4

What is upwards drilling?

Answer 4

~ if corrosion products have a high density or interfacial energy/tension, causing it to be replaced by corrosion product free liquid