138 Thornton and Hay den — Separation of Zirconium. 



On account of the great difficulty in handling these two sub- 

 stances when together in solution the authors decided to aban- 

 don the attempt to separate them in aqueous solution but to 

 recommend instead that, in the analysis of phosphatic mate- 

 rials containing zirconium, the phosphoric acid be separated at 

 the beginning of the analysis by fusion with sodium carbonate 

 and a little sodium nitrate and leaching with water, whereupon 

 sodium phosphate dissolves, leaving the residual sodium zir- 

 conate which is soluble in sulphuric acid.* 



Two solutions of zirconium sulphate were used in these 

 experiments. The first was prepared by dissolving Merck's 

 zirconium sulphate in dilute sulphuric acid, filtering, and mak- 

 ing up to definite volume. Four experiments were made with 

 the object of setting the standard of this solution. In experi- 

 ments (a) and (b) the zirconium was thrown dow r n in the hot 

 solution by redistilled ammonium hydroxide — the precipitation 

 being performed in a platinum basin. In experiments (c) and 

 (d) the zirconium was precipitated by the " cupferron " reagent 

 from a volume of 400 cm3 containing 20 cm3 of sulphuric acid 

 (made by diluting acid of sp. g. = 1*84 with an equal volume 

 of water). The following results were obtained : 



Zirconium sulphate solution Zirconium oxide 



_A_- 



(a) 25 cra3 =0 25*9545 grm 0-1088 grm. 0-4157^ 



{b) 25 cm3 =0=25-9415 grm ...0-1089 grm. 0-4198$ 



(c) 25 cm3 =0=25-978 grm 0-1091 grm. 0-4200^ 



(d) 25 cm3 =0=25-975 grm 0-1089 grm. 0*4192^ 



Since the values obtained in (b) and (<?) by two different methods 

 agree so closely,' (c) was arbitrarily taken as correct. The second 

 solution was prepared by acting on twice crystallized potas- 

 sium fluozirconate with sulphuric acid (1 : 1), warming gently 

 until all hydrofluoric acid had been displaced, pouring into 

 cold water, and making up to definite volume. This solution 

 was standardized by precipitation with the "cupferron'' 

 reagent, which had already been shown to agree well with 

 results obtained by the reliable ammonium hydroxide precip- 

 itation. Duplicate determinations gave the following results : 



Zirconium sulphate solution Zirconium oxide 



(a) 25 cm 3 =0= 26-550 grm O'llOl grm. 0-4147 '•/ 



(b) 25 cni3 =0=26'559 grm 0*1099 grm. 0'4 138$ 



The mean of these two values was taken as correct. 



The first series of experiments was performed with the 

 object of ascertaining satisfactory conditions for the separation 

 of zirconium from aluminum. Known quantities of zirconium 

 *See Hillebrand, Bull. U. S. Geological Survey, No. 422. p. 139, 1910. 



