IMPROVEMENTS IN THE TREATMENT OF PHOSPHATES OF ALUMINA TO OBTAIN A GUM HAVING DRYING PROPERTIES AND GREAT ADHESIVENESS
Year: 1879

page_text: LETTERS PATENT to George William Bremner, of No. 5, The Crescent, Clapham
Common, in the County of Surrey, for the Invention of "IMPROVEMENTS
IN THE TREATMENT OF PHOSPHATES OF ALUMINA TO OBTAIN A GUM HAVING
DRYING PROPERTIES AND GREAT ADHESIVENESS."
Sealed the 12th March 1880, in pursuance of an Order of the Lord Chancellor, and
dated the 6th September 1879.
PROVISIONAL SPECIFICATION left by the said George William Bremner
at the Office of the Commissioners of Patents on the 6th September 1879.
GEORGE WILLIAM BREMNER, of No. 5, The Crescent, Clapham Common, in the
County of Surrey. " IMPROVEMENTS IN THE TREATMENT OF PHOSPHATES OF
ALUMINA TO OBTAIN A GUM HAVING DRYING PROPERTIES AND GREAT
ADHESIVENESS.”
The object of this Invention is the treatment of natural phosphates of alumina in
a special manner, and the admixture of silicate of soda to the resulting liquid to
obtain a strong adhesive and drying substance suitable for purposes to which glue,
paste, and gum arabic (dissolved), and the like are now used.
For the purposes of my Invention I grind any natural phosphate of alumina,
preferring those known as alta-vela and redonda phosphates to a fine powder, with
which I mix twenty per cent., more or less, of plaster of Paris or gypsum. This
mixture I place in an oven or reverberatory furnace and "furnace" the mass at a
red heat for several hours, from time to time turning it over to ensure a thorough
amalgamation previous to its being withdrawn and allowed to cool. I place a
quantity of this "furnaced" product in a leaden lined vat, and add to it a solution
of sulphuric acid and water, say from five to seven parts of water to one of sulphuric
acid of the ordinary commercial strength, the solution being in a sufficient quantity
to allow the whole to be readily stirred and agitated. I add fresh diluted acid so
long as effervescence continues, and also from time to time as absorption takes place
to keep the mass from caking.
I then allow the mixture to " work itself" for a considerable time, or until it has
become thick and very glutinous. I then boil the mass with an open steam worm,
with which the vat is furnished, until it has arrived at a density of about 70° twaddle,
the boiling being then continued by a close steam worm, also in the vat, to retain

page_text: the strength or density of the material. The heat boiling is then discontinued, and
the solid particles allowed to settle that the liquid may be drawn off into another
vat, within which is also a close steam piping.
To the draw off liquid I mix (during agitation) from fifteen to twenty per cent.
of plain or furnaced gypsum or plaster of Paris, and bring this mass to boiling point
by the close steam worm, constantly stirring and agitating the mass that a thorough
combination takes place. The liquid mixture thus treated is allowed to settle, and
is readily filtered through a "Johnson or other filtering press, and run into a
Jeaden lined vessel heated either by fire or steam. To this filtered liquid I add a
solution of silicate of soda or liquid glass as a drying medium, the quantity being
in proportion and according to the purpose for which the gum is intended.
"
The employment of silicate of soda or water glass as a drying vehicle is an
essential feature in the manufacture of gum made from phosphates of alumina.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent and of
an Order of the Lord Chancellor, filed by the said George William Bremner in
the Great Seal Patent Office on the 12th March 1880.
"
GEORGE WILLIAM BREMNER, of No. 5, The Crescent, Clapham Common, in the
County of Surrey. 'IMPROVEMENTS IN THE TREATMENT OF PHOSPHATES OF
ALUMINA TO OBTAIN A GUM HAVING DRYING PROPERTIES AND GREAT
ADHESIVENESS."
This Invention has for its object improvements in the treatment of phosphates of
alumina, and its admixtures with gypsum or plaster of Paris to obtain a gum having
great drying properties, great adhesiveness, and great tenacity.
I have discovered that the gummy solution arising from the phosphates of
alumina when dissolved by the action of sulphuric or phosphoric acid are much
improved in their tenacity, adhesiveness, and drying properties when the raw
phosphates and also the resulting liquor are admixed with plaster of Paris and a
solution of silicate of soda added thereto.
For the purposes of my Invention I grind any natural phosphate of alumina,
preferring those known as "alta vela" and "redonda" phosphates to a fine powder,
with which I mix twenty per cent., more or less, of plaster of Paris or gypsum.
This mixture I place in an oven or reverberatory furnace and "furnace" the mass
to a red heat for several hours, from time to time turning it over to ensure a
thorough amalgamation previous to its being withdrawn and allowed to cool..
I place a quantity of this furnaced product in a leaden lined vat, and add to it a
solution of sulphuric acid and water, say from five to seven parts of water to one
of sulphuric acid of the ordinary commercial strength, the solution being in a
sufficient quantity to allow the whole to be readily stirred and agitated.
I add fresh diluted acid so long as effervescence continues, and also from time to
time as absorption takes place to keep the mass from caking.
I then allow the mixture to "work itself" for a considerable time, or until it has
become thick and very glutinous.
I then boil the mass with an open steam worm with which the vat is furnished
until it has arrived at a density of about 70° twaddle, the boiling being then
continued by a close steam worm, also in the vat to retain the strength or density
of the material. The heat boiling is then discontinued, and the solid particles
allowed to settle that the liquid may be drawn off into another vat within which
is also steam piping.
To the drawn off liquid I mix (during agitation) from fifteen to twenty per cent.
of plain or furnaced gypsum or plaster of Paris, and bring this mass to boiling
point by the steam worm, constantly stirring and agitating the mass that a thorough
combination takes place.
I then concentrate, if by evaporation, at a regular heat of about 160 to 190
degrees Fah., keeping it constantly and regularly stirred during concentration to
avoid it getting cloudy, adding a solution of silicate of soda or liquid glass as a
means of neutralizing the excess of acid and improving the drying properties of the
gum; and in order to increase the strength of the product I bring it up to a greater
heat, say 280 degrees Fah.; I then add such quantities of pure phosphate of alumina
as it will absorb, or until it has obtained the density required. When an increased
enamelled kind of surface is required to this gum treat it with a small quantity
of sulphate of magnesia, and when the gum has to be hardened I treat it with
sulphur.
Having now described the nature of my said Invention and in what manner the
same is to be performed, I declare that I claim,-
The preparation or treatment of phosphates of alumina as described for the pro-
duction of a gum, especially the admixture of gypsum or plaster of Paris and silicate

page_text: of soda or liquid glass as drying mediums and conducive to the tenacity, strength,
and adhesiveness of the gum.
In witness whereof, I, the said George William Bremner, have hereunto, set
my: hand and seal this Twelfth day of March, in the year of our Lord
One thousand eight hundred and eighty:
Witness,
H. GARDNER,
W
Patent Agent,
40, Fleet Street,
London.
GEORGE WILLIAM BREMNER. (L.S.),
: I