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"A Textbook of Assaying: For the Use of Those Connected with Mines."


~Ammonic Bicarbonate~ (HAmCO_{3}) is prepared by saturating a solution
of the sesquicarbonate of ammonia with carbon dioxide.
~Ammonic Chloride~, AmCl.--Use the commercial salt in a 20 per cent.
solution in water. The salt should leave no residue on ignition.
~Ammonic Molybdate.~--The solution is prepared as follows:--Dissolve 100
grams of the powdered commercial salt in 200 c.c. of dilute ammonia, and
pour the solution in a slow stream into 750 c.c. of dilute nitric acid;
make up to 1 litre, and allow the mixture to settle before using. It is
used for the purpose of separating phosphoric oxide from bases and from
other acids, and also as a test for phosphates and arsenates. In using
this solution the substance must be dissolved in nitric acid, and a
considerable excess of the reagent added (50 c.c. is sufficient to
precipitate 0.1 gram P_{2}O_{5}); when the phosphate is in excess no
precipitate will be got. The precipitate is phospho-molybdate of
ammonia.
~Ammonic Nitrate~ (AmNO_{3}) is used in the separation of phosphoric
oxide by the molybdate method, and occasionally for destroying organic
matter. It is soluble in less than its own weight of water. The solution
is made when wanted.
~Ammonic Oxalate~ (Am_{2}C_{2}O_{4}.2H_{2}O) is used chiefly for the
separation of lime. The solution is made by dissolving 15 grams of the
salt in 100 c.


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