Gravimetric determination of the abundance ratio of zirconium and hafnium, based on the in situ thermal decomposition of K(4)[(Zr,Hf)(C(2)O(4))(4)].5H(2)O

Careful heating of K(4)[(Zr,Hf)(C(2)O(4))(4)].5H(2)O results in a two-step thermal decomposition which can be written as: K(4)[(Zr,Hf(C(2)O(4))(4)].5H(2)O --> K(4)[(Zr,Hf)(C(2)O(4))(4)] --> {2K(2)CO(3)+(Zr,Hf)O(2)}. The weight-ratio of the successive decomposition products depends on the abundance ratio of Zr and Hf, and forms the basis for the present method of gravimetric determination.