IMPROVEMENTS IN THE MANUFACTURE OF OXALATES OF SODA AND POTASH
Year: 1872

page_text: LETTERS PATENT to John Dale, of the City of Manchester, in the
County of Lancaster, Chemist, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF OXALATES OF SODA AND POTASH."
Sealed the 14th January 1873, and dated the 17th July 1872.
PROVISIONAL SPECIFICATION left by the said John Dale at the
Office of the Commissioners of Patents, with his Petition, on the
17th July 1872.
I, JOHN DALE, of the City of Manchester, in the County of Lancaster,
5 Chemist, do hereby declare the nature of the said Invention for "IM-:
PROVEMENTS IN THE MANUFACTURE OF OXALATES OF SODA AND POTASH," to be as
follows:-
In the manufacture of oxylates of soda and potash I use only woody: '
fibre (principally sawdust) from which all or nearly all the impure:
matters have been removed leaving only the pure cellulose, instead of.
employing the uncleaned fibre as at present, by which means I obtain
some very great advantages.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Dale in the Great Seal Patent Office on the
17th January 1873..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
DALE, of the City of Manchester, in the County of Lancaster, Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of July, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Dale, Her special license that I, the
said John Dale, my executors, administrators, and assigns, or such others
as I, the said John Dale, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVEMENTS. IN THE MANUFACTURE OF OXALATES OF
SODA AND POTASH," upon the condition (amongst others) that I, the said
John Dale, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and. ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Dale, do hereby declare the
nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, that is to say:
In the manufacture of oxalates of soda and potash I use only the
woody fibre (principally sawdust) from which all or nearly all the
impure matters have been removed leaving only the pure cellulose,
instead of employing the uncleaned fibre 'as at present, by which means
I obtain some very great advantages.
The method for obtaining pure woody fibre or cellulose with a view to
their subsequent use for manufacturing oxalates of soda and potash
which I have found to answer best is to submit the sawdust to the
action of the caustic alkalies in their aqueous solution at a high
temperature either open or under pressure. By this means I remove

page_text: the impurities from the sawdust and obtain a product from which, on
subsequent treatment with a solution of mixed caustic soda and caustic
potash in about the proportions of two parts of soda to one part of
potash I obtain crude oxalate of soda containing a much larger amount
of oxalic acid than that prepared by the methods hitherto used.
When I desire to obtain oxalate of potash I use only caustic potash
in place of a mixture of caustic soda and 'caustic potash.
As is well known in the manufacture of oxalic acid by the action.of
caustic soda and potash or potash alone on woody fibre the recovered
alkalies require to be submitted to a high temperature in a furnace in
order to render them fit, for use a second or third time. I find that
these recovered alkalies before they are burnt are eminently suited for
treating the sawdust as described above, and thus I obtain a special
advantage from the use of these recovered alkalies before they are
calcined.
Having now described the nature and particulars of my said Invention,
and the manner in which the same is to be performed, I desire it to be
understood that I claim,-
First. The use of pure or nearly pure cellulose (obtained from sawdust
or other material by the action of caustic alkalies) in the manufacture of
oxalates of soda or potash.
Secondly. The use of the recovered alkalies in the manufacture of
oxalic acid for the purification of the sawdust or other material.
Thirdly. The use of oxalates of soda or potash so made for the manu-
facture of oxalic acid.
In witness whereof, I, the said John Dale, have hereunto set
my hand and seal, this Fifteenth day of January, in the year of
Lord One thousand eight hundred and seventy-three.
our
Signed, sealed, and delivered by the
within-named John Dale, in the
presence of
: G..SEPTIMUS HUGHES,
Patent Agent,
Manchester.
JOHN DALE. (L.S.)