IMPROVE- MENTS IN THE MANUFACTURE OF CARBONATES OF SODA AND POTASH, AND IN APPARATUS EMPLOYED THEREIN
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by Alfred Evans Fletcher at the
Office of the Commissioners of Patents, with his Petition, on the
16th May 1873.
I, ALFRED EVANS FLETCHER, of Liverpool, in the County of Lancaster,
Chemist, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF CARBONATES OF SODA AND POTASH, AND IN APPARATUS
EMPLOYED THEREIN," to be as follows:-
My Invention relates to a new and economical method or process of
producing carbonates of soda and potash, and to apparatus employed in
the said production.
Sulphurous acid, steam, and atmospheric air or oxygen are passed at
an elevated temperature through common salt contained in a converting
chamber, or a series of connected converting chambers until the salt is
converted into sulphate of soda. Through the sulphate of soda produced
as above, while hot, and preferably, in the same converting chamber or
chambers, gas or vapour containing carbonic oxide, hydrogen, and
carbon or hydrogen only, or gas, vapour, or finely pulverized matter
capable of combining with the oxygen of the sulphate of soda is forced

page_text: or drawn. If there is no hydrogen in combination or otherwise present,
the sulphate of soda is reduced to sulphide of sodium and carbonic acid
evolved. The said carbonic acid with water is then forced or drawn
through a chamber or series of chambers containing the sulphide of
sodium until this latter is converted into carbonate of soda, hydrogen 5
sulphide being driven off.
The above reactions whereby sulphate of soda is first converted into
sulphide of sodium, and then formed from the latter into carbonate of
soda need not be separated, but may be performed in one operation by
passing through the sulphate of soda at an elevated temperaturo such 1
gases as arise from the partial combustion of coal or a mixture containing
carbonaceous matter with hydrogen or hydrocarbons; by so operating
hydrogen sulphide is given off.
The hydrogen sulphide described as passing from the converting
chamber or vessel in which carbonate of soda is formed is led into a 1
sulphur, pyrites, or like burner, and there with admission of air or
oxygen burnt, thus forming sulphurous acid and water. Those with the
excess of oxygen just mentioned are led into a chamber or chambers
containing common salt to form sodium sulphate, as already described.
The manufacture is as will be seen continuous, though it may be
considered as consisting of three operations.
The same sulphur is used continuously, the small sulphur burner
described being used only to start the process, and afterwards supply
any waste that may occur through leakage or deficient absorption.
It will be evident that salts of potash may be used instead of soda
salts, and the process described followed for the production of carbonate
of potash.
The apparatus employed under my Invention consists of a series of
two or more converting chambers or vessels connected by passages, in
such manner that any one can be worked as the first, intermediate, or a
last of the series. Flues or spaces are formed around the said converting
chambers for the purpose of heating them.