IMPROVEMENTS IN THE TREATMENT OF SUBSTANCES CON- TAINING ALUMINA AND IRON FOR THE PURPOSE OF OBTAINING CERTAIN USEFUL SUBSTANCES THEREFROM
Year: 1875

page_text: LETTERS PATENT to Peter Spence, of Newton Heath, Manchester,
in the County of Lancaster, Manufacturing Chemist, and Francis
Mudie Spence, of the same Place, Manufacturing Chemist, for the
Invention of "IMPROVEMENTS IN THE TREATMENT OF SUBSTANCES CON-
TAINING ALUMINA AND IRON FOR THE PURPOSE OF OBTAINING CERTAIN USEFUL
SUBSTANCES THEREFROM."-
Sealed the 30th July 1875, and dated the 7th May 1875.
PROVISIONAL SPECIFICATION left by the said Peter Spence and
Francis Mudie Spence at the Office of the Commissioners of
Patents, with their Petition, on the 7th May 1875.
We, PETER SPENCE, of Newton Heath, Manchester, in the County of
Lancaster, Manufacturing Chemist, and FRANCIS MUDIE SPENCE, of the
same Place, Manufacturing Chemist, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE TREATMENT OF SUBSTANCES
CONTAINING ALUMINA AND IRON FOR THE PURPOSE OF OBTAINING CERTAIN USEFUL
SUBSTANCES THEREFROM," to be as follows:-
Our Invention consists in producing a cake or compound of sulphate

page_text: of alumina and iron from minerals of that class known under the name
of bauxite, and which is a variable compound of alumina and iron.
In carrying out our Invention we propose to select, by preference,
such description of the mineral as contains the largest proportion of
alumina, and we digest the same in masses with dilute sulphuric acid
in a heated state until the solution is about neutral, after which the said
solution is run off and evaporated until by trial or experience it is known
to be of that specific gravity which will cause it to assume the condition
of a cake when cooled. Or we grind the mineral to a powder and add
an ascertained quantity thereof to a measured quantity of sulphuric
acid, the powder added having sufficient alumina and iron to combine
with all the acid.
.
According to another method we take the said mineral and digest it
with the acid mother liquors of the alum manufacture, boiling the
whole together and then running it off to cool, as above described; or
the said mother liquors with sulphuric acid added thereto may be
employed. The cake of sulphate of alumina thus produced will contain
iron, but may be employed in the manufacture of: brown and other
papers; for the precipitation and purification of sewage, and for other
purposes in which sulphate of alumina is required, and in which the
presence of iron is not injurious.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Peter Spence and Francis Mudie Spence in the
Great Seal Patent Office on the 6th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, PETER
SPENCE, of Newton Heath, Manchester, in the County of Lancaster,
Manufacturing Chemist, and FRANCIS MUDIE SPENCE, of the same
Place, Manufacturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of November, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
ninth year of Her reign, did for Herself, Her heirs and successors,
give and grant unto us, the said Peter Spence and Francis Mudie
Spence, Her special license that we, the said Peter Spence and Francis

page_text: Mudie Spence, our executors, administrators, and assigns, or such
others as we, the said Peter Spence and Francis Mudie Spence, our
executors, administrators, 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 Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
<< IM-
PROVEMENTS IN THE TREATMENT OF SUBSTANCES CONTAINING ALUMINA AND IRON
FOR THE PURPOSE OF OBTAINING CERTAIN USEFUL SUBSTANCES THEREFROM,"
upon the condition, amongst others, that we, Peter Spence and
Francis Mudie Spence, by an instrument in writing under our hands
and seals, or under the hand and seal of one of us, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, 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 I, the said Francis Mudie Spence, do hereby
declare the nature of our said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, that is to say :-
Our Invention consists in producing a cake or compound of sulphate
of alumina and iron from minerals of that class known as bauxite, and
which are substantially variable compounds of alumina and iron.
The compound we have in view may be produced for use either in a
solid or liquid form, but we will in the first place refer to the plan we
adopt for the manufacture of the solid condition.
In carrying out our Invention we select, by preference, such
descriptions of the mineral as contain the largest proportion of alumina
as compared with the oxide of iron present, and place the said mineral
in masses in leaden pans, where it is digested with dilute sulphuric
acid. We usually boil the said acid on the mineral by coils of pipe
heated with steam, or by blowing the steam into the liquid, or both
methods may be adopted, and the boiling is then continued until the
acid is neutralized, that is, until the sulphate of alumina or sulphate of
alumina and sulphate of iron are free from uncombined acid, and this
condition may easily be ascertained by trial. If the liquid is now of
the specific gravity of 15 or about 100° Twaddle it is fit for the next

page_text: operation, but if not the boiling is continued until the desired strength
has been attained, and when that is the case the liquor is run into
shallow lead coolers so divided by partitions that we can turn out the
cooled material (which will then be solid) in the form of blocks, and we
find a convenient size for such blocks to be from 18 to 20 inches square,
and weighing about 1 cwt. each. The acid used in the digesting pans
we are now assuming to be diluted with water, and we run it on at a
strength of about 80° Twaddle and nearly boiling hot, but instead of
such dilution being effected by water only we sometimes use the mother
liquors of the alum manufacture in combination with sulphuric acid; or
the said mother liquors may be used alone if they contain sufficient frec
acid.
Instead of proceeding, as above described, the mineral may be ground
and added to the boiling acid until the whole of the acid has combined
with the alumina and iron.
In using the mother liquors of the alum manufacture, as above
mentioned, an additional quantity of iron would be added to the com-
pound, and when therefore a cake is desired with the smallest quantity
of contained iron we carry on the process with sulphuric acid only, but
for some purposes, as in the precipitation of sewage where the presence
of a material quantity of iron is not of much consequence, then the said
mother liquors may be employed; or such a compound may be made by
selecting the mineral with a considerable proportion of iron.
We have above alluded to our Invention as applied to the production of
a solid cake, but the compound may also be prepared so as to remain in a
fluid state, for which purpose it will simply be necessary to stop the
evaporation or otherwise to prevent the dissolved mineral from attaining
a strength which will cause it to solidify on cooling. This liquid form
may conveniently be adopted by producing it at the place where it is to
be used, as in the case of sewage works.
The cake or compound formed as above described, and which we desig-
nate alumino-ferric, although chiefly sulphate of alumina, will in all cases
contain more or less sulphate of iron, but can be employed beneficially
in the manufacture of brown, grey, and other papers, for the precipitation
and purification of sewage, and for other purposes in which sulphate of
alumina is required, and in which the presence of sulphate of iron is not
injurious.