Determination of K₂O in High Potassium Aluminosilicate by Tetraphenylborate Gravimetry

A convenient and rapid method was established to determine K₂O content in high potassium aluminosilicate(K₂O content> 15%), which was obtained by calcining K-feldspar and K₂CO₃. Combined with the GB8574-2002 potassium tetraphenylborate gravimetry method, silicon was deposited by polyethylene oxide in an acid environment. Other cations such as Mg²⁺, Fe³⁺, Fe²⁺, Mn²⁺ were removed by the intrusion of newly formed calcium hydroxide solution by controlling pH at 10-12. The remaining Al³⁺ and Ca²⁺ were eliminated by salvolatile hydrolyzation which stabilized the solution at about pH = 7.35. Before the potassium tetraphenylborate gravimetry method, the introduced ammonia was removed by low temperature(T < 473 K)calcining to avert ammonium tetraphenylborate precipitation. The relative error in this experiment was less than 0.5% by comparison with standard specimen.