Magnesium silicates are commonly used as additives in the furnace, not only to adjust the MgO content, but to facilitate the removal of potassium with the slag, thereby avoiding the formation of clumps in the furnace barrel. Of all the minerals available, only the dunite and olivine can be applied effectively.
The dunite is more effective than olivine for the following reasons:
- Their softening temperatures and melting are lower
- Possession of coordination chemistry in water causes an increase of porosity with temperature that favors their reactivity
- The phases formed after heating (clinoenstatita, bronzita and quartz) form with potassium vapors blast furnace process more stable compounds and fuse forsterite olivine