IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF ALUMINA
Year: 1876

page_text: LETTERS PATENT to James Duncan, of Mincing Lane, in the City of London,
John Alexander Reina Newlands, also of Mincing Lane aforesaid, and Benjamin
Edward Reina Newlands, of Clyde Wharf, Victoria Docks, in the County of
Essex, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE
OF ALUMINA."
Sealed the 1st September 1876, and dated the 1st July 1876.
PROVISIONAL SPECIFICATION left by the said James Duncan, John Alexander
Reina Newlands, and Benjamin Edward Reina Newlands at the Office of the
Commissioners of Patents on the 1st July 1876.
JAMES DUNCAN, of Miucing Lane, in the City of London, JOHN ALEXANDER
REINA NEWLANDS, also of Mincing Lane aforesaid, and BENJAMIN EDWARD REINA
IMPROVE-
NEWLANDS, of Clyde Wharf, Victoria Docks, in- the County of Essex.
MENTS IN THE MANUFACTURE OF SULPHATE OF ALUMINA."
Our Invention consists in producing sulphate of alumina containing a very small
percentage of iron from bauxite or similar minerals which contain a considerable
quantity of hydrate of alumina in association with peroxide of iron, silica, and
other substances, preferring to employ such kinds of bauxite or similar minerals as
contain the least iron.
In carrying out this Invention we reduce the mineral to a fine powder, and then
submit it to our process, which may be divided into two parts, viz. :—
1. The production of what is hereafter called "purified bauxite," that is, bauxite
from which a large part of the oxides of iron (which would under ordinary circum-
stances be dissolved by sulphuric acid) is removed; and
2. The treatment of this "purified bauxite" with sulphuric acid so as to form
sulphate of alumina.
(1.) We treat bauxite or similar minerals with hydrochloric acid, either strong
or dilute, for several hours, preferably at a temperature approaching the boiling
point, when a large proportion of the oxides of iron is dissolved along with a
certain amount of alumina. The solution thus obtained is run off, and the residual
mass is washed with water and then remains as "purified bauxite."
In another mode of preparing "purified bauxite" we sometimes prefer to mix the
bauxite or similar minerals with a quantity of finely ground coal, coke, charcoal, or
[Price 4d.]

page_text: other carbonaceous matters, and then to heat such mixture to a bright redness,
allowing as little access of air as possible, when the oxides of iron are reduced to a
lower state of oxidation, or even to the metallic state. We also sometimes reduce
the oxides of iron by heating the bauxite or similar minerals to bright redness, and
then passing through the mass a current of hydrogen, carbonic oxide, coal gas, or
other reducing gases.
After the oxides of iron in the bauxite or similar minerals are reduced in any of
the above-mentioned ways to a lower stage of oxidation, or to the metallic state, we
allow the mass to become cold or nearly so, and then treat it with hydrochloric acid,
either, strong or dilute, preferably at a temperature approaching the boiling point,
for several hours, when a large proportion of the iron is dissolved along with a
certain amount of alumina. The solution thus obtained is run off, and the residual
mass is washed with water and then remains as "purified bauxite."
In the preparation of "purified bauxite in any of the ways above described, in
place of using hydrochloric acid other acids may be employed, such as nitric acid,
either strong or dilute, and dilute sulphuric acid, or any mixtures of these acids
with each other, and with or without hydrochloric acid. The acid solution of iron
and alumina obtained in this part of our process may be employed for any purpose
for which a mixed salt of iron and alumina will suffice.
.
(2.) To the "purified bauxite" we now add sulphuric acid and well mix, when
in a few minutes the mixture sets into a solid mass, which yields on solution in
water a sulphate of alumina fit for all ordinary uses.
We prefer to use sulphuric acid containing about 70 per cent. of oil of vitriol,
technically known as chamber acid. Should it, however, be more convenient to
employ a stronger acid a certain amount of water should be added during the
mixing process so as to reduce the strength of the sulphuric acid to about that of
chamber acid.
The sulphate of alumina produced in the above-described way may either be used
in the state of solution or evaporated down until it forms a solid mass on cooling.
This sulphate of alumina is sufficiently free from iron for all ordinary purposes.
Should it be desired, however, to render it absolutely free from iron it is only neces-
sary to add to its cold solution ferrocyanide of potassium or sodium in quantity
sufficient to precipitate any trace of iron present.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Duncan, John Alexander Reina Newlands, and Benjamin
Edward Reina Newlands in the Great Seal Patent Office on the 29th Decem-
ber 1876.
JAMES DUNCAN, of Mincing Lane, in the City of London, JOHN ALEXANDER
REINA NEWLANDS, also of Mincing Lane aforesaid, and BENJAMIN EDWARD REINA
NEWLANDS, of Clyde Wharf, Victoria Docks, in the County of Essex. IMPROVE-
MENTS IN THE MANUFACTURE OF SULPHATE OF ALUMINA."
"
Our Invention consists in producing sulphate of alumina containing a very small
percentage of iron from bauxite or similar minerals which contain a considerable
quantity of hydrate of alumina in association with peroxide of iron, silica, and
other substances, preferring to employ such kinds of bauxite or similar minerals as
contain the least iron.
In carrying out this Invention we reduce the mineral to a fine powder, and then
submit it to our process, which may be divided into two parts, vizt.
1. The production of what is hereafter called "purified bauxite," that is, bauxite
from which a large part of the oxides of iron (which would under ordinary circum-
stances be dissolved by sulphuric acid) is removed; and

page_text: 2. The treatment of this "purified bauxite" with sulphuric acid so as to form
sulphate of alumina.
1. We treat bauxite or similar minerals with hydrochloric acid, either strong or
dilute, for several hours, preferably at a temperature approaching the boiling point,
when a large proportion of the oxides of iron is dissolved along with a certain
amount of alumina. The solution thus obtained is run off, and the residual mass is
washed with water and then remains as "purified bauxite."
In another mode of preparing "purified bauxite" we sometimes prefer to mix
the bauxite or similar minerals with a quantity of finely ground coal; coke, char-
coal, or other carbonaceous matters, and then to heat such inixture to bright red-
ness, allowing as little access of air as possible, when the oxides of iron are reduced
to a lower state of oxidation, or even to the metallic state. We also sometimes
reduce the oxides of iron by heating the bauxite or similar minerals to bright red-
ness; and then passing through the mass a current of hydrogen, carbonic oxide,
coal gas, or other reducing gases.
After the oxides of iron in the bauxite or similar minerals are reduced in any
of the above-mentioned ways to a lower stage of oxidation, or to the metallic
state, we allow the mass to become cold or nearly so, and then treat it with
hydrochloric acid, either strong or dilute, preferably at a temperature approaching
the boiling point for several hours, when a large proportion of the iron is dissolved
along with a certain amount of alumina. The solution thus obtained is run off, and
the residual mass is washed with water and then remains as purified bauxite."
"
In the preparation of "purified bauxite" in any of the ways above described, in
place of using hydrochloric acid other acids may be employed, such as nitric
acid, either strong or dilute, and dilute sulphuric acid, or any mixtures of these
acids with each other, and with or without hydrochloric acid.
The acid solution of iron and alumina obtained in this part of our process may
be employed for any purpose for which a mixed salt of iron and alumina will
suffice.
2. To the "purified bauxite" we now add sulphuric acid in quantity sufficient to
convert the whole of the alumina into sulphate of alumina and well mix, when in a
few minutes the mixture sets into a solid mass, which yields on solution in water a
sulphate of alumina fit for all ordinary uses.
We prefer to use sulphuric acid containing about 70 per cent. of oil of vitriol,
technically known as chamber acid. Should it, however, be more convenient to
employ a stronger acid a certain amount of water should be added during the
mixing process so as to reduce the strength of the sulphuric acid to about that of
chamber acid. The sulphate of alumina produced in the above-described way may
either be used in the state of solution or evaporated down until it forms a solid
mass on cooling. The sulphate of alumina is sufficiently free from iron for all
ordinary purposes. Should it be desired, however, to render it absolutely free from
iron it is only necessary to add to its cold solution ferrocyanide of potassium or
sodium in quantity sufficient to precipitate any trace of iron present.
Having now described and particularly ascertained the nature of our said Inven-
tion, and the manner in which the same is or may be used or carried into effect,
we would observe in conclusion that what we consider to be novel and original, and
therefore claim as the Invention secured to us by the herein-before in part recited
Letters Patent is―.
First. Subjecting bauxite or similar aluminous minerals to a preliminary treat-
ment with hydrochloric acid or other acids in order to eliminate the soluble oxides
of iron contained therein.
Second. In submitting bauxite or similar aluminous minerals containing oxides of
iron to the action of heat in conjunction with a reducing agent, such, for example,
as hydrogen gas, or of any carbonaceous or deoxidising agent, so as to reduce the
oxides of iron and render the iron more easily soluble in dilute acids.

page_text: Third. The employment of the bauxite or similar aluminous minerals thus
purified for the production of sulphate of alumina by acting upon the same by
means of sulphuric acid in the manner herein-before described.
In witness whereof, I, the said John Alexander Reina Newlands, on behalf of
myself and the said James Duncan and Benjamin Edward Reina Newlands,
have to this our Specification set my hand and seal, the Twenty-ninth day
of December, One thousand eight hundred and seventy-six.
JOHN ALEXANDER REINA NEWLANDS. (LS.)