IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF ALUMINA, AND IN APPARATUS EMPLOYED THEREIN
Year: 1877

page_text: LETTERS PATENT to Alexander Angus Croll, of Coleman Street, in the City
of London, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
SULPHATE OF ALUMINA, AND IN APPARATUS EMPLOYED THEREIN."
PROVISIONAL SPECIFICATION left by the said Alexander Angus Croll
at the Office of the Commissioners of Patents on the 28th July 1877.
ALEXANDER ANGUS CROLL, of Coleman Street, in the City of London. "IM-
PROVEMENTS IN THE MANUFACTURE OF SULPHATE OF ALUMINA, AND IN APPARATUS
EMPLOYED THEREIN.'
"
The object of one part of my present improvements in the manufacture of sulphate
of alumina is to arrange parts of the furnace in which the china or other aluminous
clay employed is burnt or roasted, that when the desired burning or roasting has
been effected the heat may to a large extent be retained in the product by the
accumulation of successive charges without unnecessary exposure. For this purpose
I form under or in as close communication as possible with the floor of the oven or
retort a chamber of capacity adapted to receive many successive charges of the
burnt or roasted clay from such floor. The communication to this chamber may be
direct, by an opening or openings in such floor, or it may be by a channel or
channels of communication, such opening being at all times closed except for the
discharge therethrough of the burnt or roasted clay.
By these means heat which would otherwise be lost is retained to facilitate the
subséquent action thereon of the acid employed.
Another portion of the Invention refers to the treatment of the matters during
the combination of the burnt or roasted clay with the acid. According to this part
of the Invention, when the matters in the saturating vessel have entered into com-
bination by being mixed with each other I run the contents of the saturating pan
into another vessel, adapted generally to receive a large quantity, as several
successive charges from the saturating pan, and in which such quantity is allowed to
D131

page_text: remain at rest except as to the chemical action of the particles thereof on each other
until the temperature thereof has become reduced to say, about 100° Fahrenheit,
when I separate the mass into fragments, and a convenient means to this end is by
a crowbar or otherwise to form a hole about the centre of the mass and in depth
sufficient for the purpose. Into this hole I introduce gunpowder or other explosive
compound, which when properly secured I cause to be exploded, thereby to separate
the mass into convenient sizes for commerce. I do not confine myself to this method
of effecting the desired separation.
By these means it will be found that a more intimate and complete action of the
acid with the clay is effected, and the sulphate of alumina obtained is of a superior
character for commercial purposes.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Angus Croll in the Great Seal Patent Office on the 26th
January 1878.
ALEXANDER ANGUS CROLL, of Coleman Street, in the City of London. "IM-
PROVEMENTS IN THE MANUFACTURE OF SULPHATE OF ALUMINA, AND IN APPARATUS
EMPLOYED THEREIN.
"
The object of one part of my present improvements in the manufacture of sulphate
of alumina is to arrange parts of the furnace in which the china or other aluminous
clay employed is burned or roasted, that when the desired burning or roasting has
been effected the heat may to a large extent be retained in the product by the
accumulation of successive charges without unnecessary exposure. For this purpose
I form under or in as close communication as possible with the floor of the oven or
retort a chamber of capacity adapted to receive many successive charges of the
burnt or roasted clay from such floor. The communication to this chamber may be
direct, by an opening or openings in such floor, or it may be by a channel or channels
of communication, such opening being at all times closed except for the discharge
therethrough of the burnt or roasted clay.
By these means heat which would otherwise be lost is retained to facilitate the
subsequent action thereon of the acid employed.
Another portion of the Invention refers to the treatment of the matters during
the combination of the burnt or roasted clay with the acid. According to this
part of the Invention, when the matters in the saturating vessel have entered into
combination by being mixed with each other, I run the contents of the saturating
pan into another vessel adapted generally to receive a large quantity, as several
successive charges from the saturating pan, and in which such quantity is allowed
to remain at rest except as to the chemical action of the particles thereof on each
other until the temperature thereof has become reduced to say, about 100° Fahrenheit,
when I separate the mass into fragments, and a convenient means to this end is by
a crowbar or otherwise to form a hole about the centre of the mass and in depth
sufficient for the purpose. Into this hole I introduce gunpowder or other explosive
compound, which when properly secured I cause to be exploded, thereby to separate
the mass into convenient sizes for commerce. I do not confine myself to this method
of effecting the desired separation.

page_text: By this means it will be found that a more intimate and complete action of the
acid with the clay is effected, and the sulphate of alumina obtained is of a superior
character for commercial purposes.
Having thus described iny Invention and means which I adopt in carrying the
same into effect, I would have it understood that what I do claim is,―
First. The arranging parts of furnaces employed in the manufacture of sulphate
of alumina, so that when the desired roasting or burning of the clay has been
effected the heat may to a large extent be retained in the product from such clay
by the accumulation of successive charges without unnecessary or injurious exposure
thereof, substantially as described.
Secondly. I claim the improvements in the manufacture of sulphate of alumina
by the treatment of the matters during the combination of the burnt or roasted clay
with the acid, substantially as described.
In witness whereof, I, the said Alexander Angus Croll, have hereunto set iny
hand and seal, this Eighteenth day of January, in the year of our Lord One
thousand eight hundred and seventy-eight.
A. ANGUS CROLL. (L.S.)