Improvements in the Manufacture of Alkali and Apparatus therefor.
Year: 1891

page_text: Date of Application, 16th Mar., 1891
Complete Specification Left, 13th Jan., 1892-Accepted, 13th Feb.. 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Alkali and Apparatus
therefor.
I WALTER MILLS of 20 Anstey Road Peckham London S.E. Analyst do
hereby declare the nature of this invention to be as follows :—
My invention has for its object the decomposition of common salt, whereby that
substance is converted into alkali and by product.
In order to do this I construct a crucible, retort, or furnace in a special manner;
the salt is placed in one of these and heated to the proper temperature. Or the
salt, having been heated to the proper temperature, is emptied into a vessel of
special construction which I call a
converter."
I then by suitable means cause a mixture of hydrogen and carbonic oxide gases
to pass through the heated salt. Carbonic acid gas, atmospheric air, or both
these, may also be caused to pass through the resultant mass of substance in like
manner.
Suitable means are employed for collecting any volatile product or products and
condensing the same. When the operation is complete the alkali which has been
produced is removed from the crucible or other receptacle, lixiviated if necessary
with water, filtered, and evaporated.
Dated this 16th dor of March 1901
WALTER MILLS.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Alkali and Apparatus
therefor.
I WALTER MILLS of 20 Anstey Road, Peckham, London S.E. Analyst 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: —
My invention relates to the manufacture of soda, and is based upon a discovery
which I have made, namely that if about equal volumes of hydrogen and carbonic
oxide gases are brought into contact with common salt at a proper temperature the
salt is decomposed, hydrochloric acid is given off and a mixture of sodic oxide and
carbon remains behind, in accordance with the following equation
2 NaCl + H, + CO = Na,O + C + 2 HCI.
In order to apply this discovery to the manufacture of soda I construct either
a reverberatory furnace or pan of iron in such a way that the salt may be con-
veniently fused. On the hearth of the furnace or near to the bottom of the pan
I insert tubes of iron or other suitable material perforated with holes, so as to
enable the mixed gases to be readily brought into contact with the fused salt. The
action of the mixed gases in passing through the salt is so energetic that it is
desirable to make the receptacle, in which the salt is fused, as shallow as is
conveniently practicable.
66
"
Instead of a furnace or pan I may use an apparatus identical in shape and general
arrangement with the converter employed in manufacturing steel by what is known
as the
Bessemer process."
In this case fused salt is poured into this converter,
and when it has been placed in the proper position a blast of the mixed gases is
blown through the salt. Whether a furnace, pan, or converter is employed the
result is the same.

page_text: As soon as the mixture of gases has decomposed the salt, a fluid mass of sodic
oxide and carbon remains behind. This substance may be utilised for a variety of
purposes; thus it may be introduced into a retort and distilled, so as to produce
metallic sodium. Or it may be allowed to cool, dissolved in water, and filtered so
as to remove the carbon which it contains. The aqueous sodic hydrate may then
be treated with carbonic acid gas, in which case carbonate of soda is formed, or it
may be evaporated to a solid condition and cast into drums in the manner at present
employed. Or, while the mixture of sodic oxide and carbon is still in a fluid con-
dition, atmospheric air may be blown through it, so as to oxidise the carbon and
allow the sodic oxide to remain behind in a
pure state.
In conducting the foregoing operations I need not prepare the hydrogen and
carbonic oxide gases and then mix them, as I advantageously use the ordinary and
well-known water gas, which, when free from carbonic dioxide, is a mixture of
hydrogen and carbonic oxide gases in almost equal volumes. prepare this water
gas by any of the methods at present employed but it is an advantage to use a
water gas in which the hydrogen is in excess. I therefore prefer to employ an
apparatus for manufacturing water gas which will give a product containing excess
of hydrogen. If the water gas is used in a heated state its action upon the salt is
accelerated.
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. The method of decomposing common salt by a mixture of hydrogen and
carbonic oxide gases substantially as hereinbefore described.
2. The method of decomposing common salt by water gas substantially as
hereinbefore described.
3. In the decomposition of common salt as aforesaid the use of furnaces and
pans containing perforated pipes.
4. In the decomposition of common salt as aforesaid the use of a converter
substantially as hereinbefore described.
5. The method of decarbonising a mixture of sodic oxide and carbon by
atmospheric air substantially as hereinbefore described.
Dated this 13th day of January 1892.
WALTER MILLS.