IMPROVEMENTS IN THE MANUFACTURE OF SODA
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by William Edward Newton at the
Office of the Commissioners of Patents, with his Petition, on the
16th November 1864.-A communication from abroad by Anel Bang, of
Paris, in the Empire of France,
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SODA," to be as
follows:-
This Invention of "Improvements in the Manufacture of Soda," has for its
object to produce soda in a more economical manner than heretofore, by the
double decomposition of oxalate of ammonia and hydrochlorate of soda or
common salt. To this end the Inventor takes a hot concentrated solution of
oxalate of ammonia (the preparation of which is given below), and to about
600 lbs. of oxalate of ammonia is added about 5 cwt. of hydrochlorate of soda
or common salt. Steam is then admitted thereto, and the mixture is con-
verted into oxalate of soda and hydrochlorate of ammonia. When the mass
has cooled (it being kept stirred) nearly all of the oxalate of soda (which is
not easily soluble) will be precipitated as a fine powder. The liquor remain-
ing consists of a tolerably concentrated solution of sal ammoniac and a small
portion of dissolved oxalate of soda. This liquor must be poured off, and
strained from the oxalate of soda, after which this latter must be thoroughly
washed with a cold concentrated solution of oxalate of soda. in order to

page_text: remove every trace of sal ammoniac. This nearly pure oxalate of soda is
next to be well mixed with 280 lbs. unslaked lime in the form of thin milk of
lime, steam being admitted thereto, whereby it will be converted into caustic
soda and oxalate of lime. The liquid caustic soda is then to be poured off
and converted into dry caustic soda or carbonate, the latter by the introduc-
tion of the gases of combustion until neutralized. By washing out the oxalate
of lime, less concentrated lye is obtained, and this last washing can be used
to slake the lime at the next operation (that is, at the next treatment of
oxalate of soda with unslaked lime). The already obtained solution of bydro-
chlorate of ammonia is to be decomposed with a portion of liquid chloride of
lime, which will be obtained presently, in order to convert the small portion
of oxalate of soda into insoluble oxalate of lime, which after settlement will
also be obtained.
This oxalate of lime must be well stirred with cold water and ammonia
and carbonic acid simultaneously introduced, keeping the mixture well
stirred, whereby in the hot solution it will be completely changed into
oxalate of ammonia and carbonate of lime. The ammonia will be obtained
from the liquid hydrochlorate of ammonia through heating with milk of limė
and the carbonic acid from the gases of combustion by the burning of coke.
The solution of oxalate of ammonia requires; therefore, little evaporation in
order to be used again. Most of the vessels in which the decomposition of
the several chemical agents is carried on should be close vessels. or provided
with suitable covers for the purpose of preventing the gases resulting from
the decomposition of the several salts from becoming lost, and these gases.
are to be collected and carried off by suitable pipes to other vessels where.
they may be used over again for like purposes or for a continuation of the
manufacture.