This paper is a part
summary of the results. First, I will detail my process of estimation,
then on the separation.
From all compounds of manganese, excepting those containing cobalt and
nickel, the manganese is precipitated as binoxide; those containing
these two elements are treated with phosphoric acid, or as noted under
Separation.
A.--The Estimation. The binoxide of commerce, as taken from the mine, is
well sampled, powdered, and dried at 100 deg.C. 0.5 gramme of this is taken
and placed in a 250 c.c. flask; in analysis the binoxide on the filter,
from the treatments noted under separation is thoroughly washed with
warm water; it is then washed down in a flask, as above, after breaking
the filter paper; sufficient water is added to one-third fill the flask,
and about twice the approximate weight of the binoxide in the flask of
oxalate of potassa; these are agitated together. A twice perforated
stopper is fitted to this flask, carrying through one opening a 25 c c.
pipette nearly filled with sulphuric acid, sp. gr. 1.4, the lower point
of which just dips below the mixture in the flask, and the upper end,
carrying a rubber tube and pinch cock to control the flow of acid.
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