IMPROVEMENTS IN THE MANUFACTURE OF ALKALI AND CHLORINE
Year: 1847

page_text: TO AL
LONGMAID, of London, Gentleman, send greeting.
DILAMM
YILLIADI
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, the Second day of
November, One thousand eight hundred and forty-seven, in the eleventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said William Longmaid, my exors, admors, and assigns,
Her especial licence, full power, sole privilege and authority, that I, the
said William Longmaid, my exors, adññors, and assigns, or such others as
I, the said William Longmaid, my exors, admors, or assigns, should at
any time agree with, and no others, from time to time and at all times
during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, my Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF ALKALI AND CHLORINE;" in which said Letters Patent is contained a
proviso that I, the said William Longmaid, shall cause a particular description
of the nature of my said Invention, and in what manner the same is to be
performed, by an instrument in writing under my hand and seal, to be
inrolled in Her said Majesty's High Court of Chancery within six calendar

page_text: months next and immediately after the date of the said in part recited Letters
Patent, as in and by the same, reference being thereunto had, will more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Longmaid, do hereby declare that the nature of the said Invention,
and the manner in which the same is to be performed, are fully described
and ascertained in and by the following statement thereof, that is to say:-
My Invention relates to the manufacture of alkali and chlorine,-
First, in heating sulphate of oxide of iron, or other metallic sulphates
deprived of moisture as nearly as may be, mixed with chloride of sodium in a
close furnace, with access of atmospheric air deprived of moisture, or nearly
so, heat being applied to the furnace, decomposition is effected, a product is
obtained containing sulphate of soda and oxide of iron, with evolution of
chlorine.
Secondly, in treating metallic sulphates or iron pyrites or other sulphurous
ores, mixed with chloride of potassium in a reverberatory furnace, and in
obtaining sulphate of potash, oxide of iron, or other metallic oxides.
Thirdly, in treating sulphate ash being the product of the first process above
described, or sulphate ash being the product of the decomposition of iron
pyrites or other sulphurous ores, and chloride of sodium, as described in Letters
Patent granted to me, bearing date respectively the Twentieth of October, One
thousand eight hundred and forty-two, and Fourth of August One thousand
eight hundred and forty-five, by mixing sulphate ash with small coal or other
carbonaceous matter, and heating the same in a suitable furnace.
In my first process I obtain dry sulphate of the oxide of iron by evaporating
the mother liquor of the copperas manufacture, or the crystals of green copperas,
in a reverberatory furnace at a low temperature, taking care not to expel the
sulphuric acid; the resulting product is sulphate of oxide of iron nearly free
from moisture. I then mix about seventy-eight parts by weight of such pre-
pared sulphate of oxide of iron with about sixty-parts of chloride of sodium,
which mixture I prefer to use in a finely pulverized condition. I then proceed
in the same manner I have described for producing chlorine in Letters
Patent granted to me the Fourth day of August, One thousand eight hundred
and forty-five, by which means I obtain sulphate ash containing sulphate of soda
and oxide of iron, and chlorine is evolved, which I use in the manufacture of
chloride of lime and other compounds of chlorine; or I proceed by adding
to a hot saturated solution of chloride of sodium an equivalent of sulphate of
oxide of iron or other metallic sulphate, and evaporate the mixture to dryness
in a reverberatory furnace. I then remove the partially calcined mass to a

page_text: close furnace, and proceed as before, and obtain sulphate ash containing
sulphate of soda, oxide of iron, or other metallic oxides and chlorine.
Secondly, I treat sulphate of oxide of iron or other sulphates or iron
pyrites or other sulphurous ores mixed with chloride of potassium in a rever-
beratory furnace in the same manner as is described in the said Letters
Patent granted to me, and bearing date the Twentieth day of October, One
thousand eight hundred and forty-two, when treating iron pyrites or other
sulphurous ores by chloride of sodium. The product so obtained containing
sulphate of potash and oxide of iron is then lixiviated, and the liquor so
obtained is evaporated to dryness or otherwise, and as may be found most
useful or convenient.
Thirdly, to two hundred parts by weight of sulphate ash, being the product
of either of my various processes, containing about one hundred and thirty
parts sulphate of soda, I add about seventy parts of small coal; and having
well mixed the mass I place it on the back bed of an ordinary black ash
furnace, or I prefer such furnace to have a cast-iron bed nearest the fire, and
when it is sufficiently heated I move it on to the bed nearest the fire, placing
another charge on the back bed, as is well known in the usual mode of
manufacturing black ash. In the manufacture of alkali I allow it to remain
until the charge is well fluxed, which usually happens in about fifty to sixty
minutes, I then draw it, and proceed as before. When the ball or ash so pro-
duced has remained sufficiently long to become cool, it is to be removed to the
vats, and the alkaline matter dissolved out. The liquor so obtained I pass
in intimate contact with carbonic acid by any of the ordinary means in use for
the purpose of carbonating alkaline liquors; the alkaline liquor is then
evaporated to dryness, and crude carbonate of soda or alkali of commerce is
produced.
I would here remark that in preparing the sulphate ash for the manu-
facture of alkali without the use of lime, and with one lixiviation, I select
pyrites as free from silica as possible, or I select the sulphate ash the produce
of the first process herein described. I would also remark that I am aware
that various attempts have been made to decompose chloride of sodium by
heating it with sulphate of oxide of iron in various ways; but, so far as I
am informed, such processes are of no practical value.
What I claim is,―
First, to decompose common salt with sulphate of iron, and to obtain
ulphate of soda, oxide of iron, and chlorine.
Secondly, I claim to decompose chlorine of potassium with metallic sulphates
r iron pyrites or other suluhur oro

page_text: Thirdly, I claim to work the sulphate ash into alkali at one operation,
without first lixiviating it to separate the sulphate of soda from oxide of iron
and other matters.
In witness whereof, I, the said William Longmaid, have hereunto set
my hand and seal, this Second day of May, in the year of our Lord
One thousand eight hundred and forty-eight.
Enrolled the Second day of May, in the year of our Lord One thousand
eight hundred and forty-eight.