CERTAIN IMPROVEMENTS IN THE MODE OF PREPARING AND PURIFYING ALUM, ALUMINA, ALUMINOUS MORDANTS, AND OTHER ALUMINOUS COMBINATIONS AND SOLUTIONS, AND THE APPLICATION OF SUCH IMPROVEMENTS TO THE PURPOSES OF MANUFACTURE
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
HERVEY, of Manchester, in the County of Lancaster, Drysalter, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Thirteenth day of December, in the third year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Robert Hervey, Her especial licence, full power, sole privilege, and authority,
that I, the said Robert Hervey, my executors, administrators, and assigns,
and such others as I, the said Robert Hervey, my executors, administra-
tors, and assigns, should agree with, and no other, from time to time
and at all times during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, within England and Wales, and
the Town of Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS
IN THE MODE OF PREPARING AND PURIFYING ALUM, ALUMINA, ALUMINOUS MORDANTS,
AND OTHER ALUMINOUS COMBINATIONS AND SOLUTIONS, AND THE APPLICATION OF SUCH
IMPROVEMENTS TO THE PURPOSES OF MANUFACTURE;" in which said Letters
Patent is contained a proviso that I, the said Robert Hervey, shall cause
a particular description of the nature of my said Invention, and in what
manner the same is to be performed, to be enrolled in Her Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at farge, appear..

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Robert Hervey, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described and
ascertained in and by the following explanation thereof (that is to say):-
My improvements in the mode of preparing and purifying alum, alumina,
aluminous mordants, and other aluminous combinations and solutions, and the
application of such improvements to the purposes of manufacture, consist in
the following processes:-In the first place, I take clay, selecting such as
contains the smallest quantity of iron, and which will yield the largest quantity
of alumina. This clay is then dried, and afterwards ground and passed
through a fine sieve. In this state it is put into a reverberatory furnace, and
then calcined to a moderate red heat; it is then drawn out of the furnace
and allowed to cool; after this it is put into leaden cisterns, and oil of vitriol
(sulphuric acid), diluted to the strength of from 70° to 80° of Twaddle's
hydrometer, is added to the extent of from one-half of the entire weight of
the clay used, according to the quality of the clay employed. The oil of
vitriol and clay are then to be well stirred and mixed together, when a great
ebulition or boiling ensues; after this has subsided, the mixture is again to
be well stirred, and water, cold or hot, is then gradually added to extract or
separate the sulphate of alumina thus formed. The mixture is then allowed
to settle for about forty-eight hours, when the undissolved portion of the clay
falls to the bottom, leaving sulphate of allumina above. The sulphate of
allumina is then drawn off into another leaden cistern, and the clay again
lixiviated with water to extract any remaining sulphate of alumina, which,
after settling about twenty-four hours is drawn off into another cistern, and
employed instead of water only in lixiviating a fresh quantity of clay and oil
of vitriol. The sulphate of alumina thus formed as described (according to
a process long known and practised in this country) is always impregnated
with a considerable portion of iron, to get rid of which I employ two methods:
In the first place, I add to the sulphate of alumina a quantity of prussiate of
soda or prussiate of lime, or any other combination of the prussic or ferro-
prussic acid sufficient to precipitate all the iron held in solution in the sulphate of
alumina. The supernatant sulphate of alumina thus purified is then drawn off,
and in this state is fit for the purposes of the arts. If, however, I wish to
convert the sulphate of alumina into alum (so commonly called or known),
I add thereto potash, or sulphate of potash, or other of its combinations, the
potash in which shall be equal or nearly so to the quantity of alumina con-
tained in the sulphate of alumina to be so converted into alum, or I add an
equivalent quantity of ammonia, or sulphate of ammonia, or other of its

page_text: combinations. Soda may also be used, but alum is diflicult of formation
therewith. The liquor thus containing the constituents of alumina is then
evaporated by boiling, till it attains the strength of about 70° of Twaddle's
bydrometer. It is then run off into leaden or other cisterns to chrystalize.
After cooling, the mother liquor is drawn off, and the alum salt formed is
removed from the sides and bottoms of the cisterns, and dissolved in as small
a portion of boiling water as possible. The solution is then run into large
casks called "rocking" casks, which, after the lapse of ten to fourteen days;
are taken to pieces, and the alum thus formed is broken up and is ready for the
market. For the purposes of the arts, however, the presence of an alkali is
generally injurious, and is only employed because without it the alum of com
merce cannot be formed; but for the purposes of the printer, dyer, or mordant
maker, the sulphate of alumina alone, when freed from iron, is very prefer-
able to alum. To convert the sulphate of alumina into the aluminous
mordant known in commerce by the name of red liquor, which is an acetate
of alumina, I add either a quantity of acetate of lime or lead, in sufficient
quantity for the lime or lead to unite with and carry down the sulphuric
acid of the sulphate of alumina, thus leaving a supernatant acetate of
alumina; or I take the sulphate of alumina, and by the addition of an alkali
or its combinations, such as potash, soda, or ammonia, or an alkaline earth or
its combinations, such as line or magnesia, saturate or take up all the
sulphuric acid, when the alumina no longer held in solution parcipitates.
This alumina I then re-dissolve in acetic or pyroligneous acid, which converts
it into the acetate of alumina or "red liquor" of commerce, or it can be sold
in the state of pure alumina and be dissolved by the printers or dyers, or
others, in acetic or sulphuric acid, according to the purpose for which they
wish to employ it, or I take the sulphate of alumina formed as before described
from clay and sulphuric acid, but not freed from iron, and add thereto a
suflicient quantity of acetate of lead or lime to unite with the sulphuric acid
in the sulphate of alumina, leaving a supernatant acetate of alumina to which
I add a sufficient quantity of the prussiate of potash, soda, or lime, or other com-
bination of the prussic or ferro-prussic acid, to unite with and carry down all
the iron in the acetate of alumina. After allowing it to settle, the clear liquor
must be drawn off, care being taken not to disturb the bottoms or sediment, or
I precipitate the alumina from the impure sulphate of alumina, and re-dissolve
it in acetic or pyroligeous acid, and afterwards precipitate the iron in the
manner before described.
Another method by which I free the sulphate of alumina, prepared as
before described, from iron, is as follows:-To the sulphate of alumina so

page_text: formed I add, as before described, an alkali or alkaline earth combined or
otherwise for the purpose of precipitating the alumina. As, however, in this
way the iron also precipitates along with the alumina, I re-dissolve the alumina
in caustic alkali, such as potash or soda, which will dissolve the alumina and
only a very small portion, if any, of the iron. I then draw off the clear liquor,
taking care not to disturb the bottoms or sediment, and to this liquor add
sulphuric acid, or acetic or pyroligneous or some other acid to neutralize the
alkali which holds the alumina in solution, when the alumina precipitates, and
may be sold either in that state or converted into sulphate of alumina for sale
or otherwise, or into acetate of alumina, or into the alum of commerce, by
the addition of sulphuric acid and potash or ammonia.
Having now described the particulars of my improvements, and the method
of carrying the same into practical effect, I desire it to be particularly under-
stood, that I claim as my Invention the method I have described for pre-
paring and purifying alum, alumina, and other aluminous solutions and
combinations, and also for manufacturing aluminous mordants from sulphate
of alumina and alumina instead of from the alum of commerce, in the manner
and for the purposes herein set forth.
In witness whereof, I, the said Robert Hervey, have hereunto set my
hand and scal, this Twenty-sixth day of May, in the year of our
Lord One thousand eight hundred and forty.
ROBERT (L.S.) HERVEY.
AND BE IT REMEMBERED, that on the Twenty-sixth day of May,
in the third year of the reign of Her Majesty Queen Victoria, the said
Robert Hervey came before our said Lady the Queen in Her Chancery, and
acknowledged the instrument aforesaid, and all and every thing therein
contained and specified, in form above written. And also the instrument
aforesaid was stamped according to the tenor of the Statute made in the fifty-
fifth year of the reign of Ilis late Majesty King George the Third.
Inrolled the Tenth day of June, One thousand eight hundred and
forty.