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Ammonia-Soda Wastes and
Their Disposal
U. T. GREENE
Diamond Alkali Company
Painesville, Ohio
This paper is based on a report by the Chemical Salts Industry
Committee, organized to cooperate with the Ohio River Valley Water
Sanitation Commission. That report was submitted to the Commission
last fall. Although not directly indicated by its title, this paper has
to do principally with the disposal of chlorides, a problem which in
itself could be very simple. Indeed, any disposal problem would be
a simple one if the amounts of undesired material to be handled were
small enough.
A chlorine plant could be cited as an example of a type with
relatively small amounts of chlorides to be disposed of. The products
shipped from such plants may contain 90 per cent or more of the
chloride content of the salt which they use as a feed. At the other
extreme of what might be termed "chloride efficiency," one might cite
the performance of an operation producing magnesium from sea water.
Here no attempt is made to remove chlorine from the sea water itself,
the aim being to separate the magnesium only. One might say that
here the chloride efficiency, as far as the raw material is concerned,
is zero.
Expressed differently, for each ton of magnesium in sea water, there
are about 15 tons of chloride ion (1), so that the ratio of chlorides
discarded to magnesium recovered is at least fifteen to one and in actual
practice is probably somewhat greater. Obviously, the disposal of sea
water which has simply been denuded of its magnesium content would
not be a major problem, pollutionwise, for a plant located at tidewater.
Another type of plant in which this matter of chloride efficiency is
important is exemplified by the ammonia-soda process. Since this paper
deals primarily with the by-product aspects of soda plants, perhaps a
brief consideration of the major chemical reactions involved in the
ammonia-soda process would be in order.
The following series of reactions presents in a simplified manner
what takes place in a plant of the type in question.
H20 + NH3 + C02 = NH4HCOs (1)
NH4HC03 + NaCUNaHC03 + NH4Cl (2)
2NaHC03 + HEAT = Na2C03 +H20 + C02      (3)
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