Improvements in the Treatment of the Waste from Gas Liquor to Obtain Useful Products therefrom.
Year: 1893

page_text: Date of Application, 17th June, 1893
Complete Specification Left, 16th Mar., 1894-Accepted, 21st Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of the Waste from Gas Liquor to
Obtain Useful Products therefrom.
I, HORACE WOODWARD CROWTHER, of The Beeches, West Bromwich, in the
County of Stafford, Analytical Chemist, do hereby declare the nature of this
invention to be as follows:-
After the distillation of gas liquor to obtain ammonia there remains a waste
liquor and the object of my invention is the treatment of this waste in such manner
as to render useful the sulphocyanides which it holds in solution.
I proceed as follows:-I neutralise the liquor by passing into it carbonic acid
gas, thereby causing a precipitate of carbonate of lime which I allow to settle.
To the clear neutral or slightly acid liquor I add precipitated cuprous oxide
mixed with water to a creamy consistence. This I add in quantity not quite
sufficient to decompose all the sulphocyanide present, and I then add an acid, in
this case preferably muriatic acid, in such quantity that the liquor shall at the end
of the operation have a slightly acid reaction. The mixture is agitated, and after
a few minutes it will be found that the cuprous oxide has decomposed the soluble
sulphocyanide with formation of insoluble cuprous sulphocyanide, while the base of
the soluble sulphocyanide contained in the liquor operated upon has combined with
the muriatic acid to form chloride of calcium.
When the reaction is finished the precipitate of cuprous sulphocyanide is allowed
to subside and the bulk of the liquor is run off; the cuprous sulphocyanide is then
brought on to a filter and washed to remove any soluble impurity. The insoluble
sulphocyanide of copper thus obtained is used for the production of the sulpho-
cyanide of the alkali or alkaline earth it is desired to produce by adding such
alkali or alkaline earth and water and boiling. As the result of this operation the
required sulphocyanide is obtained in solution, while hydrated cuprous oxide is
precipitated, and is separated by settling or filtration. The cuprous oxide is used
for another precipitation of sulphocyanide from other waste liquor.
I would remark that it has before been proposed in the purification of soap leys
and amongst other operations, to add to the leys a solution of a copper salt and
thereby to precipitate impurities amongst which are sulphocyanides. I, on the
contrary, in the treatment of the waste from gas liquor add to this liquor precipi-
tated cuprous oxide in a moist or creamy condition which for my purpose is much
more suitable and which in the working of the process is being constantly reproduced
and reused.
The preliminary neutralisation of the liquor with carbonic acid gas thereby
producing a precipitate of carbonate of lime is also a novel feature of my
invention.
,
There are also other differences in the processes arising out of the essentially
different natures of the liquors which are submitted to treatment.
Dated this 16th day of June 1893.

page_text: UOMI LEIE
Improvements in the Treatment of the Waste from Gas Liquor to
Obtain Useful Products therefrom.
(
1 HORACE WOODWARD CROWTHER, of The Beeches West Bromwich in the
County of Stafford, Analytical Chemist, 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 following statement :-
After the distillation of gas liquor to obtain ammonia there remains a waste
liquor and the object of my invention is the treatment of this waste liquor in such
manner as to render useful the sulphocyanides which it holds in solution.
I proceed as follows:-After the liquor is run from the still, I allow the lime to
settle, which takes place rapidly, and whilst the liquor is still hot I neutralize the
lime in solution, by passing through it gases containing carbonic acid, preferably
lime-kiln gases, I thereby obtain a precipitate of carbonate of lime which I allow
to settle. Having separated the clear liquor 1 add precipitated cuprous oxide
mixed with water to a creamy consistence. This add in quantity not quite
sufficient to decompose all the sulphocyanide present, and I then add an acid, in
this case preferably muriatic acid, in such quantity that the liquor shall at the end
of the operation have a slightly acid re-action. The mixture is agitated, and
after a few minutes it will be found that the cuprous oxide has decomposed the
soluble sulphocyanide with formation of insoluble cuprous sulpho-cyanide, while
the base of the soluble sulpho-cyanide contained in the liquor operated upon has
combined with the muriatic acid to form chloride of calcium.
When the re-action is finished the precipitate of cuprous sulphocyanide is
allowed to subside, and the bulk of the liquor is run off; the cuprous sulpho-
cyanide is then brought on to a filter and washed to remove any soluble impurity.
The insoluble sulphocyanide of copper thus obtained is used for the production
of the sulpho-cyanide of the alkali or alkaline earth it is desired to produce by
adding such alkali as hydrate or carbonate-preferably hydrate, or alkaline earth
as oxide or hydrate and water and boiling. As the result of this operation the
required sulphocyanide is obtained in solution, while hydrated cuprous oxide is
precipitated, and is separated preferably by settling. The cuprous oxide is used
for another precipitation of sulphocyanide from other waste liquor.
I would remark that it has before been proposed in the purification of
soap leys
and amongst other operations, to add to the leys a solution of a copper salt and
thereby to precipitate impurities amongst which are sulphocyanides. 1, on the
contrary, in the treatment of the waste from gas liquor, add to this liquor precipi-
tated cuprous oxide in a moist or creamy condition which for my purpose is much
more suitable and which in the working of the process is being constantly reproduced
and re-used.
The preliminary neutralisation of the liquor with carbonic acid gas thereby
producing a precipitate of carbonate of lime is also a novel feature of my
invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
] claim is
1. The treatment of the waste liquor left after the distillation of ammonia from
gas liquor, to obtain therefrom a sulphocyanide of an alkali or of an alkaline earth,
by adding precipitated cuprous oxide to the said waste liquor thereby forming
cuprous sulphocyanide, and then further treating the cuprous sulphocyanide with
an alkali or alkaline earth substantially as described.

page_text: 2. The preparation of the said waste liquor for treatment in accordance with
Claim 1 by the precipitation and separation therefrom, of carbonate of lime, by
means of carbonic acid gas substantially as described.
3. The treatment of the said waste liquor substantially as herein described.
Dated this Eighth day of March 1894.
HORACE WOODWARD CROWTHER.