Improvements in the Treatment of Soda Waste.
Year: 1890

page_text: Date of Application, 8th Dec., 1890
Complete Specification Left, 17th Sept., 1891-Accepted, 5th Dec., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Soda Waste.
I, FRANCIS ELLERSHAUSEN, of Hebburn-on-Tyne, in the County of Durham,
Alkali Manufacturer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the treatment of the waste obtained in treating sulphide
of sodium solution for the manufacture of caustic soda, either directly with hydroxide
of iron, or indirectly with ferrate of soda.
According to my present invention this waste, which is a double sulphuret of
iron and sodium is converted directly into ferrate of soda by treating it with
carbonic acid so that the sulphur contained in the same is driven off as sulphuretted
hydrogen and the soda converted into carbonate of soda, which, together with the
iron, on being re-heated are converted again into ferrate of soda.
In carrying out my invention I advantageously wash the waste whilst in a moist
condition with carbonic acid whereby the sulphuretted hydrogen is eliminated and
I then heat the remainder until the ferrate is formed.
After the treatment with carbonic acid I sometimes mix with the resulting mass
bi-carbonate of soda and I heat the mixture.
Dated the 8th day of December 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Treatment of Soda Waste.
I, FRANCIS ELLERSHAUSEN, of Hebburn-on-Tyne, in the County of Durham,
Alkali Manufacturer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the f. llowing statement :-
My invention relates to the treatment of the waste obtained in treating sulphide
of sodium solution either with hydroxide of iron or with ferrate of soda, for the
manufacture of caustic soda.
This waste is a double sulphuret of iron and sodium and in order to eliminate the
sulphur and convert the remaining mass into ferrate of soda I advantageously wash
the waste whilst in a moist condition with carbonic acid, whereby sulphuretted
hydrogen is given off and I then heat the remainder until the ferrate is formed.
For this purpose the waste is placed in a closed vessel and carbonic acid gas is
forced therethrough until the sulphur is driven off. The remaining mass which
consists of carbonate of soda and oxide of iron is then removed and placed
in a reverberatory furnace where it is heated to convert it into ferrate of soda.
I sometimes combine the two operations of treating with carbonic acid and
heating, that is to say, I treat the mass with carbonic acid whilst the said mass
is in a heated condition. In this case the waste is placed preferably in a dry
condition into a muffle furnace and carbonic acid gas is passed therethrough.
After the sulphur is driven off the supply of carbonic acid is shut off and the
heat is continued to convert the mass remaining in the muffle into ferrate
of soda.
With this treatment under the action of heat sulphur fumes instead of sulphuretted
hydrogen are given off, which sulphur fumes may be condensed by any suitable
means

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
Treating soda waste of the kind hereinbefore referred to with carbonic acid,
substantially as, and for the purpose, set forth.
Dated the 16th day of September 1891.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.