Obtaining Useful Products from Refuse or Residues of Gas Purifying and Apparatus therefor.
Year: 1889

page_text: Date of Application, 7th May, 1889
Specification Accepted, 8th June, 1889
Obtaining Useful Products from Refuse or Residues of Gas Purifying
and Apparatus therefor.
I, CHARLES DUBOIS of No. 9 rue de la Republique, Marseilles in the Republic of
France, 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 following statement
--
The cyanides contained in the old or refuse materials which have been employed
in the purification of lighting gas have been utilised in the manufacture of prussian
blue and in the preparation of prussiates of potash but the relatively small demand
for these products has until now prevented the complete utilisation of these
cyanides
The process which I, have invented and which forms the object of the present
invention enables the whole to be utilised and is based on a conversion of the
cyanides into ammonia the flow of which is easy and almost unlimited.
This conversion is based upon the decomposition of cyanides at a high temperature.
It is consequently sufficient in order to obtain this decomposition to heat in suitable
apparatus the old or refuse materials which have been employed in the purification
of lighting gas. The animonia and ammoniacal compounds produced are afterwards
collected either on sulphuric acid to form sulphate of ammonia or in condensing
chambers in order to extract ammoniacal liquids for further treatment.
Nevertheless it may sometimes occur that the whole of the hydrocyanic acid in the
cyanides is not decomposed into ammonia and that a portion thereof escapes, in
order to collect the whole of this product it is necessary to cause the vapours and
gases escaping from the sulphuric acid to pass into a bath of milk of lime or into a
solution of potassa or soda. cyanides are thereby reformed which may be subjected to
further treatment
To facilitate the decomposition of the cyandes and accelerate the operation a
current of steam super-heated or otherwise is introduced into the apparatus or
chamber in which the old or refuse purifying materials are heated this steam being
condensed on leaving the apparatus retains the ammonia and the ammoniacal salts
produced.
The process is preferably conducted in an apparatus such as that illustrated in the
This apparatus
accompanying drawing which represents the apparatus in section.
consists mainly of a rotary retort A mounted on hollow trunnions B B₁ supported by
suitable bearings P P arranged outside a brickwork chamber M enclosing the
retort and provided at its lower part with grates or fireplaces F F for heating the
annaratus.

page_text: The retort A is constructed with suitable manholes or openings provided with
covers for introducing and discharging the materials under treatment and superheated
or other steam can be injected into the interior by means of a steam pipe T provided
with nozzles t
The driving gear and steam pipe are attached to one of the trunnions (B) and
the gaseous products generated escape through the other trunnion (B¹). In practice
the distribution pipe extending into the interior of the retort may be dispensed with
the steam being simply caused to enter the retort through the hollow trannion
This steam, superheated or otherwise, carries over with the greatest rapidity the
gaseous products and the sulphur which is vaporised without prejudice to the
chemical or mechanical action that it may produce in the presence of such complex
products as those contained in the used up or refuse materials which have been
employed in the purification of gas.
The process performed according to my invention with the aid of apparatus such as
that illustrated in the accompanying drawing and which does not require further
description as to its details which will be readily understood by referring to the
illustration presents the important advantage of extracting in one operation from the
refuse purifying materials employed in the manufacture of gas 1st the sulphur which
may be estimated at 40 per cent. and 2ndly the ammonia contained in the ammoniacal
salts of these products. Moreover this process has the advantage not only of
extracting in the form of ammoniacal salts, the ammonia contained in the old
purifying materials but also of decomposing the hydrocyanic and ferro hydrocyanıc
acids and converting them into ammonia or ammoniacal salts which thus further
increase the output.
When the old purifying materials are introduced into the retort and the apparatus
is started the vapours generated are conducted to a condensing chamber where the
sulphur is deposited. This chamber being sufficiently heated retains the sulphur
only whilst the vapours being invariably charged with ammonia and ammoniacal salts
are conducted to refrigerators wherein they are condensed and yield ammoniacal
liquids or they are conducted over sulphuric acid in order to form sulphate of
ammonia. The heat generated by the reaction is sufficient to evaporate the water.
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
1. For treating old or refuse materials (which have been employed in the purifi-
cation of lighting gas) for the purpose of utilising the cyanides therein contained the
process consisting in heating the said materials in order to convert them into
ammonia substantially as herein before described.
2. Heating old or refuse materials (which have been used in the purification of
lighting gas) in combination with the injection of superheated or other steam for
the purpose of extracting from the said materials and converting into ammonia, the
cyanides which they contain substantially as hereinbefore described.
3. For treating old or refuse materials (which have been employed in the purifica-
tion of lighting gas) by heating and injecting superheated or other steam for the
purpose of extracting therefrom and converting into ammonia the cyanides which
they contain the arrangement and construction of apparatus provided with a rotary
retort A mounted on hollow trunnions B B with or without a steam pipe T and
arranged over a fire place or fire places substantially as hereinbefore described and
illustrated in the accompanying drawings.
Dated this 7th day of May 1880