IMPROVEMENTS IN THE MANUFACTURE OF ALUMINA AND SALTS OF ALUMINA FROM BLAST FURNACE SLAG OR FROM OTHER SILICATES OF ALUMINA CONTAINING AN EXCESS OF LINE OR MAGNESIA
Year: 1867

page_text: LETTERS PATENT to William Crossley and Thomas Charles Hutchinson,
both of Middlesborough-on-Tees, in the County of York, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF ALUMINA AND SALTS OF ALUMINA
FROM BLAST FURNACE SLAG OR FROM OTHER SILICATES OF ALUMINA CONTAINING
AN EXCESS OF LINE OR MAGNESIA."
Sealed the 15th April 1868, and dated the 21st October 1867.
PROVISIONAL SPECIFICATION left by the said William Crossley and
Thomas Charles Hutchinson at the Office of the Commissioners of
Patents, with their Petition, on the 21st October 1867.
We, WILLIAM CROSSLEY and THOMAS CHARLES HUTCHINSON, both of
Middlesborough-on-Tees, in the County of York, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF LUMINA
AND SALTS OF ALUMINA FROM BLAST FURNACE SLAG OR FROM OTHER SILICATES OF
ALUMINA CONTAINING AN EXCESS OF LIME OR MAGNESIA," to be as follows:-
This Invention consists in certain improved processes for the manufacture
of alumina and salts of alumina by means of the decomposition of blast
furnace slag or other silicates of alumina. The slag or other silicate is
subjected to the action of hydrochloric acid, the mixture being then evaporated
to dryness, and the soluble chlorides dissolved out from the dried mass.
The alumina is thus left mixed with the silica, and may be readily dissolved
by any soluble acid, and filtered from the silica. The salt of alumina pro- .

page_text: duced is then separated by evaporation and crystallization in the usual and
well-known manner.
As an example of the manner in which this Invention can be carried into
effect, the following mode of applying it to the manufacture of sulphate of
alumina from Cleveland blast furnace slag may be described:-The slag to be
operated upon is first reduced to the state of powder, and is then placed in a
suitable vessel; a proportion of hydrochloric acid (usually an equal weight)
is then added, and the mixture allowed to stand until the whole of the slag is
fully decomposed, the decomposition being facilitated if desired by the appli-
cation of heat; the mass resulting from this operation is then evaporated to
dryness, and the product lixiviated until all the soluble chlorides are dissolved
out; the insoluble portion, which consists principally of silica and alumina,
is then treated with sulphuric acid, and the sulphate of alumina thus produced
is separated from the silica by washing, and may be obtained by evaporation
and crystallized in the usual way, or as crude salt may be obtained by merely
adding the acid and crystallizing without removing the silica.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Crossley and Thomas Charles Hutchinson in the
Great Seal Patent Office on the 20th April 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
CROSSLEY and THOMAS CHARLES HUTCHINSON, both of Middlesborougb-on-Tees,
in the County of York, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of October, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her beirs and successors, give and grant unto us, the
said William Crossley and Thomas Charles Hutchinson, Her special licence
that we, the said William Crossley and Thomas Charles Hutchinson, our
executors, administrators, and assigns, or such others as we, the said
William Crossley and Thomas Charles Hutchinson, our executors, adminis-
trators, 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 King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of Man,
an Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ALUMINA AND SALTS
OF ALUMINA FROM BLAST FURNACE SLAG OR FROM OTHER SILICATES OF ALUMINA CON-

page_text: TAINING AN EXCESS OF LIME OR MAGNESIA," upon the condition (amongst others)
that we, the said William Crossley and Thomas Charles Hutchinson, our
executors or administrators, by an instrument in writing under our, 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 per-
formed, 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 we, the said William Crossley and Thomas Charles
Hutchinson, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, that is to say :-
Our said Invention consists in certain improved processes for the manufacture
of alumina and salts of alumina by means of the decomposition of blast
furnace slag or other silicates of alumina containing an excess of lime or
magnesia.
In the first place the slag or other silicate is subjected to the action of
hydrochloric acid, the mixture being then evaporated to dryness, and the
soluble chlorides afterwards dissolved out from the dried mass. The alumina
is thus left mixed with the silica, and may be readily dissolved by any
suitable acid, as will be well understood by persons conversant with chemical
operations, and filtered or washed from the silica; the salt of alumina pro-
duced by this process is then separated by evaporation and crystallization in
the usual and well-known manner.
As an example of the manner in which our said Invention can be carried
into effect, the following mode of applying it to the manufacture of sulphate
of alumina from Cleveland blast furnace slag may be described :-The slag
to be operated upon is first reduced to a state of fine powder, and is then
placed in a suitable vessel; a proportion of hydrochloric acid (usually an
equal weight) is then added, and the residue allowed to stand until the whole
of the slag is fully decomposed, the decomposition being facilitated if desired
by the application of heat; the mass resulting from this operation is then
evaporated to dryness, and the product lixiviated until all the soluble chlorides
are dissolved out; the insoluble portion, which consists principally of silica and
alumina, is then treated with sulphuric acid, and the sulphate of alumina thus
produced is separated from the silica by washing, and may be obtained by
evaporation and crystallization in the usual way, or may be obtained in the
form of crude salt by merely adding the acid, and proceeding to crystallization
without removing the silica.

page_text: Having thus declared the nature of our said Invention, and the manner in
which it is to be performed, we would observe in conclusion that what we
consider novel and original and therefore claim as constituting the Invention
secured to us by the said herein-before in part recited Letters Patent are, the
processes for and methods of manufacturing alumina and salts of alumina
herein-before described and set forth, or any mere modifications thereof.
In witness whereof, we, the said William Crossley and Thomas Charles
Hutchinson, have hereunto set our hands and seals, this Seventeenth
day of April, in the year of our Lord One thousand eight hundred
and sixty-eight.
WILLIAM CROSSLEY.
(L.S.)
THO. C. HUTCHINSON. (L.B.)