IMPROVEMENTS IN THE MANUFACTURE OF COMPOUNDS OF ALUMINA AND OF MAGNESIA
Year: 1857

page_text: LETTERS PATENT to David Baker, of the Gisbro Alum Works, Yorkshire,.
for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF COMPOUNDS
OF ALUMINA AND OF MAGNESIA."
Sealed the 1st May 1857, and dated the 12th February 1857.
PROVISIONAL SPECIFICATION left by the said David Baker at the
Office of the Commissioners of Patents, with his Petition, on tho
12th February 1857.
I, DAVID BAKER, of Gisbro Alum Works, Yorkshire, do hereby declare
the nature of the Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
COMPOUNDS OF ALUMINA AND OF MAGNESIA," to be as follows:-
This Invention has for its object improvements in the manufacture of
compounds of alumina and of magnesia. For these purposes, in making a
compound of sulphate of alumina and clay, the liquors obtained from alum
rock or other aluminous shales, by the application of sulphuric acid to the
burnt shales, or by adding water in the usual way, are used; such liquors
obtained by either process are evaporated to a certain gravity, when clay is
added, by preference China or Dorset clay, and the mass is allowed to solidify.
When using shales containing alumina and magnesia, as in the case of
the Yorkshire alum shales, the compound produced, as above explained, will.
consist of sulphate of alumina, sulphate of magnesia, and clay. In some cases,

page_text: sulphate of magnesia obtained as at the Yorkshire alum works, or manu-
factured from magnesian limestone and sulphuric acid, is used, and having
brought a solution to the desired gravity by evaporation the clay is added, as
before explained, and the compound is allowed to solidify. In some cases a
compound is prepared to be used as well as the preceding in place of alum,
although applicable for purposes where greater purity is requisite; the
sulphate of ammonia, sulphate of potash, muriate of ammonia, muriate of
potash or soda, one of which salts is necessary for the manufacture of. alum,
being in this preparation dispensed with. For this purpose are used liquors
obtained either by the application of sulphuric acid to the calcined aluminous
shales or rock or by adding water in the usual way, such liquors containing
sulphates of alumina, or if from shales or rock of the nature of the Yorkshire
alum rock, then containing sulphate of alumina and sulphate of magnesia.
In this manufacture the clarified liquors obtained by either of the processes
before stated, when containing sulphate of alumina only, are evaporated to the
proper gravity and then drawn off to solidify, or when the liquors contain
both sulphate of alumina and sulphate of magnesia they are evaporated in the
manner before described, and when a known gravity is attained the sulphate
of alumina is separated from the sulphate of magnesia, and in cooling solidifies,
the former being the product desired. There is a resideum precipitated in
clarifying aluminous liquors which has hitherto been run to waste. It con-
tains in the Yorkshire, and such like shales, portions of sulphates of alumina
and magnesia, which being evaporated is used by me in making a preparation
or compound for paper stainers, and for making common papers.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed 2
by the said David Baker in the Great Seal Patcut Office on the 12th
August 1857.
1.
.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID.
BAKER, of the Gisbro Alum Works, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Hér Letters:
Patent, bearing date the Twelfth day of February, in the year of cour. Lord
One thousand eight hundred and fifty-seven in the twentieth year of Her
reign, did for Herself, Her, heirs and successors, give and grant unto me, the
said David Baker, Her special licénce that I; the said David Baker, my
executors, administrators, and assigns, or, such others as I; thelisaid David)

page_text: Baker, my 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, excrcise,
,and: vend; within the United Kingdom of Great Britain and Ireland; the
5. Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF COMPOUNDS OP ALUMINA AND OF MAGNESIA," upon the condition
(amongst others) that I,.the.said David Baker, my executors or adminis-
(trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of
-the. said; Invention,.tand 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
*Patént.
1.
NOW KNOW YE, that I, the said David Baker, do hereby declare the
5.nature of the said Invention, and in what, manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say.
196
This Invention has for its object improvements in the manufacture of
compounds of alumina, and of magnesia. For these purposes, in making a
compound of sulphate of alumina and clay, the liquors. obtained from alum
rock or other aluminous shales, by the application of sulphuric acid to the
burnt shales, or by adding water in the usual way, are used. Such liquors
obtained by either process are evaporated to a certain gravity, when clay is
added, by preference China or Dorset clay, and the mass is allowed to
solidify.
...
In carrying out this part of my Invention I prefer to employ large lead
'pans heated by under flues. The liquor is heatedeso: as quickly to evaporate
the excess of liquor and bring the same to about 95° of Twaddel; when a
quantity of clay in a state of powderris, stirred in, so as intimately to; mix the
compound; the quantity of clay used may be varied, but it is. preferred to
employ at the rate of about one of the clay (to nineteen of the liquor when
brought to the specific gravity above mentioned: When the clay has been
well stirred in, which will take from, about 10 to 15 minutes, the whole is run
off to solidify,. the stirring being continued sof long as it can be conveniently
done. The compound thus produced is suitable for paper makers and others
in substitution of alum, and other aluminous compounds, where great purity is
not required. When using.shales containing alumina and magnesia, as in the
case of the Yorkshire alum shales, the compound produced as above explained

page_text: will consist of sulphate of alumina, sulphate of magnesia, and clay. In some
cases sulphate of magnesia obtained as at the Yorkshire alum works, or
manufactured from magnesian limestone and sulphuric acid, is used, and
having brought a solution to the desired gravity above described by evaporation,
the clay is added, as before explained, and the compound is allowed to solidify.
These compounds, like the first described, are applicable in the manufacture of
paper, and otherwise where great purity is not desired. In some cases a
compound is prepared to be used as well as the preceding (in place. of alum)
although applicable for purposes where greater purity is requisite; the sulphate
of ammonia, sulphate of potash, muriate of ammonia, muriate of potash or
soda, one of which salts is necessary for the manufacture of alum, being in
this preparation dispensed with. For this purpose are used liquors obtained
either by the application of sulphuric acid to the calcined aluminous shales or
rock or by adding water in the ordinary way, such liquors containing sulphate
of alumina; or if from shales or rock of the nature of the Yorkshire alum rock
then containing sulphate. of alumina and sulphate of magnesia. In this
manufacture the clarified liquors obtained by either of the processes before
stated, when containing sulphate of alumina only, are evaporated to the
proper gravity (about 96° of Twaddel) and then drawn off to solidify; and
this preparation is suitable for the paper maker for the finer classes of paper,
as well as for other uses; or, when the liquors contain both sulphate of
alumina and sulphate of magnesia, they are evaporated in the manner before
described and allowed to solidify, when, as in the previous case, the product
will be suitable for the paper maker and others. The quantity of sulphate of
alumina or of sulphate of magnesia may be varied from those naturally
contained in the liquors by adding the one or other when evaporating the
liquor. I find it advantageous when great purity is desired to continue the
application of heat some hours after the liquors have been run off, which
allows time for the settling of impurities; or when a known gravity is
attained (from 96° to 106° of Twaddel) the sulphate of alumina is separated
from the sulphate of magnesia, by the sulphate of magnesia being driven off
by heat; I then introduce sufficient of the soda of commerce or other alkali
to neutralize any free acid consequent on driving off the magnesia. In cooling.
the product solidifies, and is the product desired, and is suitable in the
manufacture of finer classes of paper and other uses. There is a residuum
precipitated in clarifying aluminous liquors which has
to waste.
hitherto been run
In the Yorkshire shales and those of like nature it contains portions of

page_text: sulphates of alumina and magnesia, the moisture of which being evaporated
is used by me in making a preparation or compound for paper stainers, and
for making common papers.
In witness whereof, I, the said David Baker, have hereunto set my
hand and seal, this Twelfth day of August, in the year of our Lord
One thousand eight hundred and fifty-seven.
Witness,
Jxo. ALCOCK.
DAVID BAKER. (L.S.)