A purple coloured cobalt pyrophosphate (Co_{2}P_{2}O_{7}) is thus
formed, and is weighed. It contains 40.3 per cent. of cobalt.
The mixed filtrates containing the nickel are placed in a tall beaker,
and dilated if necessary to about 200 c.c. Ten c.c. of strong ammonia
are added, and the solution, heated to 70° C., is ready for
electrolysis. A battery of two 1-1/2 pint Bunsen cells is used. This is
found capable of depositing from .15 to .20 gram of nickel per hour, and
from two to three hours is generally sufficient for the electrolysis.
The electrode with the deposited nickel is washed with distilled water,
afterwards with alcohol as described under copper, and is then dried and
weighed.
The following results obtained with this method by Mr. Hope illustrate
the accuracy of the method. They were obtained by working on solutions
containing known weights of the two metals:
-------------------------+-------------------------
Taken. | Found.
------------+------------+------------+------------
Cobalt. | Nickel. | Cobalt. | Nickel.
------------+------------+------------+------------
.1236 gram | .1155 gram | .1242 gram | .1155 gram
.1236 " | .0577 " | .1232 " | .0575 "
.2472 " | .0577 " | .2449 " | .0585 "
.3708 " | .
Pages:
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808