Ceramics-Silikáty 38, (2) 93 - 98 (1994)

Potentiometry using the potassium ion-selective electrode can be conveniently employed to determine rapidly the approximate content of K₂O in silicate raw materials. For the determination, the dried and ignited sample of the material is decomposed by reflux boiling in hydrochloric acid (9 mol dm⁻³). Aliquote amounts are taken from the suspension obtained so as to receive a resulting K₂O content over the range of 10⁻² to 1.5 x 10⁻⁵ mol dm⁻³ at pH of 0.7 to 0.9. Under the given conditions, the interfering effect of hydrogen ions occurs only at pK⁺ = 5.