SEPARATION. OF IRON- FROM’NICKEL. AND COBALT. 161 
with ammonium hydrate (the sulphuric acid present in the 
case of some ores etc. interferes with the ether extraction) 
before applying the separation of the chlorides. Acetone’ 
may be added to the ether. The separation has been 
elucidated by Speller.”. A minimum of hydrochloric acid 
of strictly 1°1—1°11 S.G. should be used to dissolve the 
chlorides, 5 cc. of ether being added per “1 grm. of Fe. Two 
separations are made. The ether extraction process has 
yet to be tested as thoroughly as Kern tested it for iron 
from uranium. A slight alteration of the concentration of 
the reagents afiects considerably the behaviour of the cobalt. 
7. Field’s Process. 
Field* proposed the method examined in the following 
experiments. It is based on the precipitation by litharge 
of iron as ferric hydrate from a neutral solution of the 
nitrates of iron, nickel and cobalt. He gave two results 
of test analyses in support for nickel, but none for cobalt. 
Cheney and Richards’ found ‘‘ by far the best success was 
obtained in the use of the method given by Field,’’ but 
Moore’ says “ Field’s process . . cannot be recommended.”’ 
Experimental—Advantages of Field’s Method. 
An enquiry into the accuracy of Field’s method was 
made, as it had distinct advantages over methods commonly 
in use, viz., a single precipitation of the iron, and the 
absence, after the removal of the added lead, of all reagents 
such as ammonium or sodium salts. When combined with 
the electrolytic determination of nickel and cobalt the 
method becomes more rapid than say a double precipitation 
of the iron by the basic acetate process and the precipita- 
1 Norris—Journ. Soc. Chem. Ind., xx., 6, 1901. 
? Speller—C.N. 1901, Lxxxu1., 124; Sargent—Journ. Am. Chem. Soc., 
Oct. 1899, 854. 
* Journ. Am. Chem. Soc., xx111., 10, 1902. 
ete. 1859, &., 5. 
72 N 9877, xxxvi., 161. 4 C.N., 1886, Liv., 306. 
