Improvements in the Treatment of Alkali Waste to Obtain Sulphuretted Hydrogen and other Products and in Apparatus Employed to Obtain these Substances.
Year: 1888

page_text: Date of Application. 30th Jan., 1888
Complete Specification Left, 30th Oct., 1888
Complete Specification Accepted, 14th Dec., 1888
Improvements in the Treatment of Alkali Waste to
Obtain
Sulphuretted Hydrogen and other Products and in Apparatus
Employed to Obtain these Substances.
We JAMES HARGREAVES Chemist THOMAS ROBINSON Ironfounder and JOHN
HARGREAVES Chemist all of Widnes in the county of Lancaster, do hereby declare
the nature of this invention to be as follows:-
Our process relates to various improvements in the treatment of alkali waste to
obtain sulphurettel hydrogen, sulphur, cement, and carbonic acid gas and in apparatus
employed for obtaining these substances.
In carrying our invention into effect we mix sufficient clay with alkali waste to
combine and form cement with the lime contained in the waste. By preference we
form the mixture into bricks or pieces, place it in a series of chambers and pass
through or amongst the packed mass, steam sufficiently superheated to decompose the
alkali waste and drive off the sulphur therein contained, as sulphuretted hydrogen,
the sulphuretted hydrogen may be used to give sulphur or sulphuric acid. The
heating of the packed mass is further continued to form cement, by means of super-
heated steam or other suitable heating gases.
When it is desired to treat as above described, oxidised alkali waste, we previous to
heating the mass, mix suitable carbonaceous inaterial (such as coal) with the mixture
of alkali waste and clay, or we deoxidise the alkali waste whilst it is maintained at a
high temperature, by means of suitable deoxidising gases.
In treating recently produced alkali waste by means of carbonic acid gas to evolve
sulphuretted hydrogen we employ a chamber or series of chambers having a number
of shelves placed one above another upon which shelves, by mechanical means, the
waste is constantly moved and fresh surfaces exposed to the carbonic acid gas and the
waste allowed to fall from one shelf to another.

page_text: To make cement and obtain strong carbonic acid gas from carbonated alkali waste,
we remove sulphur and excess of alkali if present, by washing, mix clay with the
carbonated waste, heat the mixture with highly superheated steam and condense the
steam evolved along with the carbonic acid gas, which latter may be employed as
desired.
Improvements in the Treatment of Alkali
Waste to Obtain
Sulphuretted Hydrogen and other Products and in Apparatus
Employed to Obtain these Substances.
We JAMES HARGREAVES Chemist, THOMAS ROBINSON Ironfounder, and JOHN
HARGREAVES Chemist all of Widnes in the County of Lancaster 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 :-
:-
Our process relates to various improvements in the treatment of alkali waste to
obtain sulphuretted hydrogen, sulphur, cement, and carbonic acid gas, and in apparatus
employed for obtaining these substances, an important object being to so eliminate
sulphur and alkali from the alkali waste as to leave the lime therein contained
sufficiently pure for the manufacture of high class cement. To more clearly explain
the improvements and the method of putting the same into practice we will now
describe the improvements under separate heads.
1. Under the first part we mix sufficient clay with alkali waste to combine with the
lime and form cement.
The proportion of clay we employ for this purpose is about one part of clay to three
parts of lime calculated as carbonate.
Alkali waste usually contains more soda than is desired in the manufacture of.
cement. A considerable proportion of such soda is in a condition not readily soluble
in water, being aluminates silicates or double sulphides of sodium and iron. To
render such insoluble soda capable of -elimination we add to the alkali waste previous
to mixing it with clay sufficient chloride of calcium to react upon and render soluble
the insoluble soda salts above mentioned which latter we climinate by washing with
water. The reaction would be hastened by heating the mass.

page_text: The mixture of alkali waste and clay is under this part of our invention formed into
bricks or pieces and packed in a series of chambers. Through or amongst the packed
mass we pass steam sufficiently superheated to decompose the alkali waste and
eliminate the sulphur as sulphuretted bydrogen. The alkali waste and clay are after
the heating by superheated steam heated to a high temperature by any suitable means
to form cement.
When superheated steam is used and the alkali waste is in a powdery condition the
apparatus described under the following third head may be used.
The sulphuretted hydrogen may be used to give sulphur or sulphuric acid as may
be desired.
When the apparatus described under the third head is employed it is better to
transfer the treated mixture to and complete the heating in a separate roasting
chamber, such as the revolver furnace mentioned under the fourth head hereafter.
II. When it is desired to treat as hereinbefore described oxidized alkali waste, by
which we refer more particularly to waste heaps which have been deposited for a
considerable period, and sulphides of calcium have become converted into hyposulphite,
sulphite, sulphates or other compounds of sulphur and lime we wash the oxidized
alkali waste with water preferably hot to remove soda, and mix the waste with clay as
described under the first head and also with suitable carbonaceous material (such as
coal) in quantity sufficient to deoxidize the sulphur compounds, or we deoxidize the
alkali waste whilst it is maintained at a high temperature by means of suitable
deoxidizing gases passed previous to or mixed with the superheated steam, through or
amongst the mixture of alkali waste and clay.
11
III. In treating recently produced alkali waste by means of carbonic acid gas to
evolve sulphuretted hydrogen, we employ a chamber or series of chambers having
number of shelves placed one above another, upon which shelves by mechanical
means the waste is constantly moved, fresh surfaces being exposed to the ascending
carbonic acid gas and allowed to fall from one shelf to another. The carbonic acid gas
entering the lower part of the chamber is first brought into contact with the most
nearly carbonated waste and ascends the interior of the chamber in reverse direction
to the descending waste. The chamber or chainbers are preferably constructed of iron
and arranged in the manner described in the Hargreaves & Robinsons apparatus for
absorption of gases by solids. We provide arrangements for injecting a spray of
water upon the lower shelves and arrange suitable circulating pipes or other media
through which is or are conveyed steam or cold water to heat or cool the gases or
alkali waste undergoing treatment in the chamber.
When carbonating the alkali waste it is necessary that such waste be maintained in
a moist but friable condition and not in such a pasty condition as to close the
interstices and prevent diffusion of the reacting gases through the mass.
After carbonation the waste is exposed to the air in heaps, or otherwise brought in
contact with air, kept warm and moist or wet by which any undecomposed sulphides
are oxidized. Sulphur in combination as sulphate of lime is rendered soluble by
means of the carbonate of soda invariably contained in alkali waste, and is more
rapidly rendered soluble when in a wet condition and heated. Alkali and sulphur are
finally removed by washing with water as herein described preferably whilst hot and
by means of a centrifugal machine or other suitable hydro extractor.
IV. To make cement and obtain strong carbonic acid gas from carbonated alkali
waste we remove sulphur and alkali by washing as described under the foregoing first
and third heads.
We then thoroughly and intimately mix preferably in a wet or moist condition
about three parts of the said carbonated and washed alkali waste with about one part
of clay and heat the mixture in suitable series of vessels or chambers with highly
superheated steam at a temperature preferably above 1500 deg. Fah. For super-
heating the steam we prefer to employ the ordinary packed brick reheater or
regenerator.
We condense the steam evolved along with the carbonic acid gas in suitable
condensing or collecting pipes or chambers. The carbonic acid may be employed as

page_text: may be desired. By its use as described under the third head a continuous stream of
sulphuretted hydrogen only slightly diluted may be obtained from alkali waste.
To remove free sulphur where such exists from carbonated and washed alkali waste
after being mixed with clay and whilst roasting to form cement we roast the mixture
in long revolving furnaces so that the mixture is gradually heated by the cooler
residual products of combustion coming from the hotter portion of the revolving
furnace to distil the free sulphur at low temperature and avoid oxidation of the same
whilst in actual contact with the lime.
Having now particularly described and ascertained. the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
First. Mixing alkali waste with clay and treating the mixture with superheated
steam to evolve sulphuretted hydrogen substantially as set forth.
Second. Forming mixed alkali waste and clay into bricks or pieces, placing the
same in a chamber or series of chambers and subjecting them to the action of super-
heated steam to eliminate sulphuretted hydrogen and leaving the residue in a suitable
condition for use in the manufacture of cement substantially as set forth.
Third. After admixture and treatment under the above first and second claims
further heating of the mass to form cement substantially as set forth.
Fourth. Treating oxidized alkali waste by washing with water to remove soda,
subsequently mixing with clay and carbonaceous matter, or reducing by reducing gas
and subjecting the mass to the action of superheated steam to remove sulphur, and
finally raising the temperature to produce cement substantially as set forth.
Fifth. Subjecting moist alkali waste whilst it is being passed over shelves in a
tower or close chamber to the action of a current of carbonic acid gas the said gas
being caused to pass in the opposite direction to that of the waste so as to eliminate
the sulphur as sulphuretted hydrogen sufficiently strong for use in the manufacture of
sulphur or its acids substantially as set forth.
Sixth. Purifying the waste obtained under the fifth claim by washing so as to
remove sulphur and alkali substantially as set forth.
Seventh. Adding to the purified waste obtained under the above sixth claim, clay,
treating the same and forming cement substantially as set forth.
Eighth. Mixing carbonated alkali waste with clay subjecting the mixed mass to the
action of highly superheated steam thereby evolving strong carbonic acid gas and
leaving the mass in a fit state for use in the manufacture of cement substantially as
set forth.
Ninth. Subjecting carbonated alkali waste to washing substantially as set forth,
subsequently adding clay, treating the mass and making cement.
Tenth. The several apparatus herein described for the purposes set forth.
Dadad this 90th awe of Onta 1000