IMPROVEMENTS IN THE MANUFACTURE OP ALKALIES
Year: 1866

page_text: LETTERS PATENT to John Williamson, of South Shields, Alkali Manu-
facturer, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OP
ALKALIES."
Sealed the 5th April 1867, and dated the 6th December 1866.
PROVISIONAL SPECIFICATION left by the said John Williamson at
the Office of the Commissioners of Patents, with his Petition, on the
6th December 1866.
I, JOHN WILLIAMSON, of South Shields, Alkali Manufacturer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE MANU-.
FACTURE OF ALKALIES," to be as follows:-
It is well known to alkali makers that the vat liquors of black ash contain
iron in solution in the form of ferrocyanide of sodium, which contaminates and
discolours the products obtained therefrom. I destroy this compound by
heating the vat liquors under pressure in an iron boiler capable of standing a
bigh pressure until they attain a temperature of about three hundred and ten
degrees (310°) Fahrenheit, when the ferrocyanide is decomposed and the
iron it contains is rendered insoluble, and can be separated by settling or
filtration. The same process is applicable to the decomposition of ferrocyanide
of potassium when potash is the alkali under treatment.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Williamson in the Great Seal Patent Office on the
6th June 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME I, JOHN
WILLIAMSON, of South Shields, Alkali Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of December, in the year of our
Lord One thousand eight hundred and sixty-six, in the thirtieth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Williamson, Her special licence that I, the said John
Williamson, my executors, administrators, and assigns, or such others as
I, the said John Williamson, 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 Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF ALKALIES," upon the condition
(amongst others) that I, the said John Williamson, my executors or adminis-
trators, 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 Williamson, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
It is well known to alkali makers that the vat liquors of black ash contain
iron in solution in the form of ferrocyanide of sodium, which contaminates and
discolors the products obtained therefrom. I destroy this compound by
heating the vat liquors under pressure in an iron boiler capable of standing a
high pressure until they attain a temperature of about three hundred and ten
degrees (310°) Fahrenheit, when the ferrocyanide is decomposed, and the
iron it contains is rendered insoluble, and can be separated by settling or
filtration. The same process is applicable to the decomposition of ferrocyanide
of potassium when potash is the alkali under treatment.
And in order that my said Invention may be most fully understood and

page_text: readily carried into effect, I will proceed to describe the method in which I
prefer to conduct the manufacture.
In the manufacture of soda I take the liquor obtained by the lixiviation of
the black ash in the usual way; I prefer that this liquor should be of full
strength, or nearly so, and I run it into a steam boiler capable of sustaining
a heavy pressure; this boiler may be of any ordinary construction, but I find
that a cylindrical boiler with hemispherical ends and without internal flues is the
most convenient. In this boiler I heat the liquor, and as soon as the pressure
passes 80 lbs. on the square inch I draw samples from time to time and test
for ferrocyanide, and when this is no longer found the process is so far
complete. I prefer to weight the safety valve of the boiler to 120 lbs. on the
inch, so that whilst the valve allows of a sufficient temperature and pressure
being in all cases obtained it will still protect the boiler from undue strains;
the fire is then damped or withdrawn and the steam is blown off, and when
the furnace is sufficiently cool the contents of the boiler are drawn out and
the boiler is re-charged for another operation. The liquor drawn from the
boiler is allowed to settle, or is filtered, and is then treated in the way which
is usual with black ash liquor, it is either evaporated for soda ash, or it is set
to crystallize to obtain crystals of soda. The method of treating potash
liquors is in all respects similar.
In witness whereof, I, the said John Williamson, have hereunto set my
hand and seal, this Sixth day of June, in the year of our Lord One
thousand eight hundred and sixty-seven.
JOHN WILLIAMSON. (L.B.)