A NEW COMBINATION OF FURNACES FOR USE FOR THE MANUFACTURE OF SULPHIDE OF SODIUM AND SULPRIDE OF POTASSIUM, APPLICABLE ALSO TO THE MANUFACTURE OF 'BLACK ASH.
Year: 1876

page_text: LETTERS PATENT to Walter Weldon, of Abbey Lodge, Merton, in the County of
Surrey, for the Invention of "A NEW COMBINATION OF FURNACES FOR USE FOR
THE MANUFACTURE OF SULPHIDE OF SODIUM AND SULPRIDE OF POTASSIUM,
APPLICABLE ALSO TO THE MANUFACTURE OF 'BLACK ASH.'
"
OJOT
August
107 AU DARD DH
Sealed the 24th November 1870,
PROVISIONAL SPECIFICATION left by the said Walter Weldon at the Office
of the Commissioners of Patents on the 28th August 1876.
WALTER WELDON, of Abbey Lodge, Merton, in the County of Surrey. "A NEW
COMBINATION OF FURNACES FOR USE FOR THE MANUFACTURE OF SULPHIDE OF
SODIUM AND SULPHIDE OF POTASSIUM, APPLICABLE ALSO TO THE MANUFACTURE OF
'BLACK ASH."
"
This Invention has reference primarily to the manufacture of sulphide of sodium
and sulphide of potassium by the reaction of carbonaceous matter upon sulphate of
soda and sulphate of potash. It is also applicable to the manufacture of "black ash."
It will be convenient in what follows to speak only of sulphate of soda and
sulphide of sodium, but all that will be said of these compounds will be equally
applicable to sulphate of potash and sulphide of potassium
In another Specification which will be deposited at the Patent Office on the same
day as this, I have described a new method of obtaining sulphide of sodium by the
reaction upon sulphate of soda of powdered coke or charcoal, which method consists
in heating the two bodies separately in distinct furnaces, in which the sulphide of
sodium shall be heated at least to fusion and the powdered coke or charcoal
preferably at least to redness, and in then mixing together the sulphate of soda and
the coke or charcoal only after they shall have separately been raised to such a
temperature or such temperatures that on their being brought into mutual contact

page_text: reaction can take place between them without the application of more heat, or by
the application of much less heat than would require to be applied to the mixture if
its two constituents had not previously been heated separately.
My prosent Invention has reference to the combination of furnaces necessary for
carrying this method of obtaining sulphide of sodium into effect, and to the manner
of disposing, connecting, and combining such furnaces. The said combination must
include at least two furnaces, one for heating the powdered coke or charcoal, which
I will call furnace "A," and the other for heating the sulphate of soda, which I will
call furnace "B." The furnace which I have called "A" should preferably be of the
kind known to alkali manufacturers as the "revolving furnace," such furnace being
a long cylinder placed horizontally, arranged so as to be capable of revolving on its
longer axis, and having an opening at each end to permit of its contents being
heated by the passage into and through it of products of combustion. The
furnace "A," however, must differ from the revolving furnaces at present in use
among alkali makers in two particulars, it must be so lined and protected by
blocks of either agglomerated and hardly compacted carbon or agglomerated and
hardly compacted magnesia as to render it inattackable by sulphide of sodium,
which would completely destroy in a very short time any revolving furnace at
present in use; and it must be provided with appliances for cutting off at will the
entry into it of products of combustion, and of completely closing the opening at
one of its ends, so as to admit of its being converted at will into a vessel having
only one open aperture. The furnace "B" may be of any other of several kinds, but
I prefer that it should be what is known as a Siemens's regenerative furnace. The
hearth or bed of furnace "B" must be at such an elevation that when sulphate of soda
has been fused upon this hearth or bed, such fused sulphate of soda can run into
furnace "A," on the channel of communication between the two furnaces which must
be provided for that purpose being opened. Finally the dispositions should be such
that the flame or products of combustion produced in furnace B can be passed at
will through the furnace A; or a special furnace for providing such products of
combustion may be employed.
Instead of furnace "B" being a Siemens's furnace, it may be a cupola furnace or a
reverberatory furnace preferably heated by gas, in order to avoid contamination of
the sulphate of soda by dust or ashes; it may also be a revolving furnace placed
above the revolving furnace "A," in such wise that the fused sulphate of soda may
run from it into furnace A through the charging doors of the two furnaces
respectively; or, when the sulphate of soda is manufactured in the mechanical
furnace invented by Messieurs Jones and Walsh, that furnace may be so adapted to
and combined with furnace A, and may be so provided with appliances for further
heating the charge in it after such charge has been completely converted into
sulphate, that the sulphate of soda may be fused in the same furnace as that in
which it was manufactured, and may be thence run directly into the furnace in
which it is to be decomposed.
When the above described combination of furnaces is to be employed for the
manufacture of black ash, the revolving furnace need not necessarily be lined in the
new manner aforesaid, and it need not necessarily be provided with means of
converting it at will into a vessel closed at one end.
When the said combination of furnaces is employed for the manufacture of
sulphide of sodium or sulphide of potassium, the opening at that end of the revolving
furnace at which, when products of combustion are passed into and through such
furnace, the said products of combustion pass out of it, should be capable of being
connected at will with either of two conduits, one leading to a chimney through a
regenerator or otherwise to be used when products of combustion are being passed
into and through the furnace, and the other leading to either gasometers for storing
or to apparatus for utilizing carbonic acid, to be used when carbonic acid gas and
sulphide of sodium are being simultaneously produced therein. At the other end of
the revolving furnace the dispositions must be such that the annular disc suspended

page_text: between the revolving furnace and the furnace or combustion chamber which
supplies it with products of combustion, and through the aperture in the centre of
which the said products of combustion enter the revolving furnace, may be moved
away at will and a carbon disc without any aperture be readily attached to that
end of the furnace in such manner that when the furnace is in motion the carbon
disc shall move, and that, so long as it is so affixed to that end of the furnace it
shall keep that end of the furnace completely closed.