Chemical phase-analysis for kyanites.
A new method is presented for determining the kyanite present in a refractory aluminium silicate rock. The sample is digested with hydrofluoric acid for 2-3 hr, the excess of acid is removed or complexed and the residue is filtered off, dried and weighed. The residue is the undissolved kyanite and any topaz and tourmaline present. Corrections may be applied for the solubility of kyanite in hydrofluoric acid and for the topaz. Many non-refractory aluminium silicate minerals tested were found to be decomposed almost completely by this treatment. Corundum, tourmaline and certain garnet minerals, besides topaz, may be left undissolved, however, and interfere.
Tewari
D N
DN
C-4, Mosaboni Mines, Singhbhum Bihar, India.