In some articles and books about steelmaking in general, I read about 'acid' SiO2 slags and 'basic' CaO slags.
I thought that were only valid for aqueous solutions. How does acids and bases work in hot slags ?
Because they are ionic salt solutions where the most abundant salt is the solvent instead of water and the temperature is 1500 C instead of at most
100 C ?
I assume that this is the case but is that true ?unionised - 7-11-2021 at 05:50
Metal oxides are anhydrides, they form acids and bases with water. And they tend to react in a similar way to produce the same compounds. This concept
is also used in cement and refractory chemistry. j_sum1 - 7-11-2021 at 14:23
I should know because I spent a lot of time on this at uni. But it has been a long time and it is possible that I did not ever get a deep
understanding of all the details here.
The general idea is that the purpose of the slag is to separate out impurities in the iron-making and steel-making processes.
In iron-making, the bulk of the slag comes from components of the ore and you do not get much control over its composition. But it is possible to add
SiO2 or CaO to control the slag chemistry somewhat.
In the steel-making process, the composition of the slag is controlled more tightly to extract whatever impurities remain in the melt. Depending on
what is there, oxygen and/or an inert gas may be bubbled through the melt to react with impurities and float them to the surface.
Slags may also be employed in the casting process - to fine-tune the composition in the tundish or even in the mould.wg48temp9 - 8-11-2021 at 01:10
Slags may also be employed in the casting process - to fine-tune the composition in the tundish or even in the mould.
Initially I thought the word tundish was a spelling mistake as I do not remember reading it previously but I could not think of a word it was supposed
tobe.
So I googled it. Its a gas inlet device. The plumbing version can refer to an anti siphon valve that may contain a one way valve to let air in to the
drain system to prevent the water in u bends being sucked out.
