IMPROVEMENTS IN THE MANUFACTURE OF ALUM AND ALUMINOUS SALTS
Year: 1868

page_text: LETTERS PATENT to Peter Spence, of Newton Heath, near Manchester,
in the County of Lancaster, Manufacturing Chemist, for the Inven-
tion of "IMPROVEMENTS IN THE MANUFACTURE OF ALUM AND ALUMINOUS
SALTS."
Sealed the 11th June 1869, and dated the 19th December 1868.
PROVISIONAL SPECIFICATION left by the said Peter Spence at the
Office of the Commissioners of Patents, with his Petition, on the
19th December 1868.
I, PETER SPENCE, of Newton Heath, near Manchester, in the County
of Lancaster, Manufacturing Chemist, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ALUM AND
ALUMINOUS SALTS," to be as follows:-
My Invention relates, firstly, to the manufacture of alum from shale
of the coal measures when calcined, the object being to obtain with
comparative speed a clear solution of sulphate of alumina, which is
converted into alum in the usual manner by adding sulphate of potash
or sulphate of ammonia. For this purpose I avoid grinding the shale

page_text: into powder and use it in a granulated form by passing it through a
sieve of say from 8 to 20 meshes to the lineal inch. This granulated
shale I then digest in the necessary quantity of sulphuric acid required
to extract the alumina, and the result in a few hours is a comparatively
clear solution, which is ready for conversion into alum.
My Invention in the manufacture of aluminous salts consists in
operating upon raw or uncalcined shale in a granulated or other form
for the extraction of iron, and obtaining therefrom sulphate and other
compounds of alumina.
In carrying out this part of my Invention I take shale from the coal
measures or other source containing by preference the smallest quantity
of iron. These shales I granulate through a sieve of 8 or 20 meshes;
I then place it in wooden vessels and add muriatic acid of commerce
and let it stand 48 hours, and a small degree of heat may be applied.
I find that the acid dissolves out a considerable portion of the iron, and
I now wash out the solution, then drain the material and calcine it in
any ordinary furnace at a low red heat from 3 to 4 hours. I now digest
it with the required quantity of sulphuric acid for dissolving out the
alumina, if for the production of sulphate of alumina, and I obtain a
clear solution of the sulphate nearly free from iron and suitable for the
manufacture of "cake alum" of commerce.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Peter Spence in the Great Seal Patent Office on
the 18th June 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, Í, PETER
SPENCE, of Newton Heath, near Manchester, in the County of Lancaster,
Manufacturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of December, One
thousand eight hundred and sixty-eight, and in the thirty-second year a
of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Peter Spence, Her special licensc that I, the
said Peter Spence, my executors, administrators, and assigns, or such
others as I, the said Peter Spence, my exccutors, administrators, and

page_text: 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 "IMPROVEMENTS IN THE MANUFACTURE OF ALUM AND
ALUMINOUS SALTS," upon the condition, amongst others, that I, the said
Peter Spence, by an instrument in writing under my hand and seal.
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 Scal Patent Office within six
calendar months next and immediately after the date of the said Letters.
Patent..
NOW KNOW YE, that I, the said Peter Spence, do hereby declare
the nature of my 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):
My Invention relates, firstly, to the manufacture of alum from shule,.
the object being to obtain with comparative speed a clear solution of
sulphate of alumina, which is converted into alum in the usual manner.
Secondly. In operating upon raw or uncalcined shale or indurated
clays in a granulated form for the extraction of iron and obtaining
therefrom sulphate and other compounds of alumina..
In carrying out the first part of my Invention I take the calcined
shale now used in the manufacture of alum according to the mode
specified under a Patent granted to me, bearing date Twenty-seventh
November One thousand eight hundred and forty-five, Number 10,970,
but before digesting the said shale in sulphuric acid I grind or otherwise.
bring it into a divided state, so that it will pass through a sieve of eight
to twelve meshes per lineal inch, taking care as far as possible to avoid
the production of dust. I now place this granulated shale in a lead.
lined vessel heated by coils of pipe containing steam of from twenty-five
to forty pounds pressure, and add sulphuric acid diluted to about 1.375.
specific gravity, and maintain the heat at from 225° to 235° F. And
I will now describe a form of digesting vessel and method of using it
which I prefer :-I take a lead lined vessel, say twenty feet long, six
feet broad, and two feet deep, divided into three compartments length-
ways by partitions of lead of sufficient strength, pierced with numerous
small holes to allow the liquor to pass through, but sufficiently small'

page_text: to arrest the passage of the granulated shale. In the central partition
I place the shale, so that it nearly fills it. I then fill up the entire vessel
with sulphuric acid diluted as before mentioned, and by means of a
pump or similar apparatus pass the liquor continuously from one side
division of the vessel to the other, so that it is constantly passing
through the central compartment which contains the granulated shale,
which granulations are prevented from accompanying the liquor by
means of the leaden partition, but the said liquor can pass through the
perforations thereof. A temperature from 225° to 235° F. is kept up
by a coil of closed steam pipe, and I find that in four or five hours the
solution has become a nearly saturated solution of alumina in sulphuric
acid, and I run it off for the manufacture of alum by the addition of
ammonia or potash, as is well known.
In carrying out my improvement in the manufacture of aluminous
salts I take the shales or indurated clays from the coal measures or from
other sources, and in selecting these I prefer to obtain those which
contain a large proportion of alumina, say from 25 to 35 per cent. of
alumina, and which at the same time contain only a small proportion
of iron. These shales or indurated clays I take in their dry and hard
condition, not allowing them to be weathered by the atmosphere, and I
bring them into granulations that will pass through a sieve of eight to
twelve meshes to the lineal inch; and if much fine dust is produced
during the grinding I pass the granulated material over a fine sieve to
remove the said dust. I now take the granulated substance and place it
in a wooden tank containing say from ten to twenty tons, and cover
it with water containing seven and a half per cent. of the weight of
the granulated material of hydrochloric acid of commerce. After the
whole has stood for two days I run the solution off and wash the
material with water until it is cleansed from the solution, and after
draining I calcinc it for two or three hours at a low heat of barely
visible redness in the dark, and I now find this substance ready for the
extraction of alumina. For this purpose I place it in vessels as before
described for the manufacture of alum, and having calculated the
amount of sulphuric acid required I add it diluted to 1.40 specific
gravity, and the steam being applied and the temperature kept up as
before I continue to transfer the liquor from side to side as described in
reference to the manufacture of alum, and in a few hours (say from
three to five) I find that I have a solution of sulphate of alumina ready

page_text: for running off to form into cakes or plates of sulphate of alumina, as is
well known, and I find that the hydrochloric acid having removed all
the iron which was in a soluble condition the sulphate of alumina so
produced is as practically free from iron as that which is made from
china clay. Of other aluminous salts, aluminates of soda and potash
may be produced from the granulated substance by using solutions of
cautic soda or caustic potash instead of sulphuric acid, and proceeding
as above described.
Having thus described and ascertained the nature of my said Inven-
tion, and the manner in which the same is to be performed, I desire it
to be understood that I claim as secured to me under the above in part
recited Letters Patent, the manufacture of alum and also aluminous salts
by treating shales or indurated clays substantially as above described.
In witness whereof, I, the said Peter Spence, have hereunto set
my hand and seal, this Seventeenth day of June, in the year
of our Lord One thousand eight hundred and sixty-nine.