IMPROVEMENTS IN THE MEANS AND APPARATUS FOR MANUFACTURING ALKALI, WHICH IMPROVEMENTS ARE PARTLY APPLICABLE TO OTHER PURPOSES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by William Alexander Lyttle at
the Office of the Commissioners of Patents, with his Petition, on
the 6th February 1875.
I, WILLIAM ALEXANDER LYTTLE, of the Grove, Hammersmith, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR
MANUFACTURING ALKALI, WHICH IMPROVEMENTS ARE PARTLY APPLICABLE TO OTHER
PURPOSES," to be as follows:-
F
I prepare sulphate of sodium in the ordinary way, and then convert it
directly into solution of caustic soda by precipitating the whole of the
sulphuric acid of the sulphate by means of hydrate of baryta obtained
in the following cheap and peculiar manner devised by me:- -Sulphate
of baryta is finely ground up or otherwise incorporated in a powdered
state with coal dust, coke dust, wood charcoal dust, or the dust of peat
charcoal, and then agglomerated into lumps without the use of lime, in
any of the various methods, by clay or raw wet peat, together or
separately, described in the Specification of my Letters Patent dated the
First day of September in last year, entitled "Improvements in the
Manufacture of Iron and Steel." These lumps with or without being

page_text: dried, are then charged into a reducing furnace and exposed to the
action of an ascending blast of carbonic oxide flame, in precisely the
same way as the iron ore is directed to be reduced in the Specification of
my aforesaid Patent, with this exception, that the temperature of the
carbonic oxide should be as high as possible: By this means a con-
tinuous process of deoxidating the sulphate of baryta and reducing it to
sulphide of barium will be attained, each lump exposed to the action of
the flame being precisely in the same chemical conditon as a covered
crucible filled with the same incorporated materials, and reduced by the
heat of a furnace applied externally to the crucible. The carbonic
oxide in this case is not only the most direct and economical vehicle of
required heat, but a powerful reducing agent. This sulphide of barium
is next reduced to protoxide of barium or hydrate of baryta, for use in
precipitating the sulphuric acid of sulphate of sodium in the manner
heroin-after mentioned.
.
If ferric oxide or powdered hæmatite ore is mixed with the sulphate
of barium and carbonaceous matter in preparing the said lumps of
compound for reduction by carbonic oxide as described, the play of
reactions which follow under the influence of the high temperature will
result in the partial or complete conversion of the sulphate of barium
into protoxide of barium and the conversion of the ferric oxide into ferric
sulphide. This baric oxide can be removed by water as hydrate for
further use in making caustic soda as described, whilst the greater part
of the sulphur can be recovered from the ferric sulphide in the usual
way by making sulphuric acid therefrom. This acid will be again.
available for the preparation of sulphate of sodium, and the ferric oxide
remaining after the removal of the sulphur in making the sulphuric
acid will be specially well suited for further use in the desulphurization
of sulphate of barium, as already described.
Instead of reducing the sulphate of barium by intermixed car-
bonaceous matter and ferric oxide as described above, the ferric oxide or
other material rich in iron is first reduced to the unfused metallic state
in accordance with the process in my aforesaid iron and steel Patent,
and this metallic iron powder, without separating from it the mineral
and charcoal or coke powders which it may contain, may be thoroughly
incorporated with the sulphate of barium and carbonaceous matter, in
such proportion that there shall be enough iron to form sulphide with
all the sulphur present. This mixture may be made into lumps of

page_text: compound by means of plastic clay or wet peat as already described, and
subjected to the action of the carbonic oxide flame in the reducing
furnace as herein-before described.
When sulphide of barium is formed from sulphate of baryta as
aforesaid, it may be decomposed and converted into protoxide of barium
by igniting or calcining it at a high temperature in an intimately
incorporated state with the oxide of iron or copper, or of any other metal
having a stronger affinity than barium for sulphur, or it may be
converted into protoxide of barium or carbonate of baryta by boiling it
in water with an admixture of at least one equivalent proportion of
oxide of zinc or carbonate of zinc, or of the oxide of any other metal
which is now known, like that of zinc, to possess the property of taking
the sulphur from the sulphide of barium when boiled in a powdered
state therewith in water.
If the protoxide or hydrate of baryta is allowed to absorb carbonic
anhydride from the atmosphere or from an oxidizing flame of a
reverberatory furnace, the result of its use in precipitating the sulphuric
acid of sulphate of sodium will be that the released alkali will be in the
form of carbonate of sodium. The same process applies in all respects
to the manufacture of hydrate or carbonate of potassium from sulphate
of potassium, and the protoxide or hydrate or carbonate of baryta
produced from the sulphate of baryta as herein-before described, the
preparation of which is the special feature of this my process, is also
applicable with great economy in all those operations of chemical
technology in which it is necessary to separate sulphuric acid by
precipitation from combination with any basic substance.