|Monthly Tech-Tip |
Alternate Names: Illmenite, Ferrous Titanate, Iron Titanate
Like rutile, ilmenite is quite variable in nature. Actually, more variable since it would likely come from the same deposit, it being the more iron-stained part. You can tell the difference between granular rutile and granular ilmenite by doing a smear test against an abrasive surface (i.e. an unglazed white tile). The rutile stains tan or brown, the ilmenite black or dark brown. Under a microscope the ilmenite will be an opaque black whereas the rutile crystals will be somewhat translucent or transparent.
Ilmenite can be used in small amounts (-1%) to produce dark brown specks in bodies and specialized glazes. It also is used in combination with rutile to develop characteristic rutile break glazes; it seeds crystals in titania glazes.
If your production depends on consistency of this material, consider testing each batch of this material received by mixing it with a boron frit and doing a GBMF test. Variations in chemistry will be immediately evident.
An illmenite colored glaze (GR6-H) at cone 6 oxidation
Illmenite at Wikipedia
Materials that source Na2O, K2O, Li2O, CaO, MgO and other fluxes but are not feldspars or frits. Remember that materials can be flux sources but also perform many other roles. For example, talc is a flux in high temperature glazes, but a matting agent in low temperatures ones. It can also be a flux, a filler and an expansion increaser in bodies.
Generic materials are those with no brand name. Normally they are theoretical, the chemistry portrays what a specimen would be if it had no contamination. Generic materials are helpful in educational situations where students need to study material theory (later they graduate to dealing with real world materials). They are also helpful where the chemistry of an actual material is not known. Often the accuracy of calculations is sufficient using generic materials.
Titanium Dioxide Toxicology
|Frit Softening Point||1365C|
|Density (Specific Gravity)||4.80|
|Glaze Crystallization||Ilmenite seeds crystals in titania glazes.|
|Glaze Variegation||Ilmenite can be used with rutile to produce classic rutile-breaking glazes. Use up to 2% ilmenite.|