What are the limitations of vitrification?
Waste vitrification is extremely adaptable. It is easier to identify the few practical limitations than to discuss the whole range of acceptable wastes suitable for vitrification. Glass can be made of almost anything if cooled quickly enough. For the purposes here we will limit the consideration to silicate glasses that when formed are chemically durable materials. Although there are many exceptions, this criteria requires that silica be greater than 30 to 35 wt % and the silica + alumina + zirconia be above about 45 wt % while the alkali oxides (sodium, potassium, lithium) be less than ~20 wt %. Sometimes the solubility of element oxides are low and crystals form that can settle out in the melter. This can cause refractory accumulation inside the melter. To avoid this problem, low cost soils may be added to the waste to reduce the concentration of selected element oxides. There are glass material and equipment constraints that need to be considered for different waste streams. Even fo
