IMPROVE- MENTS IN THE MANUFACTURE AND PREPARATION OF MAGNESIA AND, SOME OF ITS SALTS
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
RICHARDSON, of Newcastle-upon-Tyne, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-third day of
January (One thousand eight hundred and fifty-two), in the fifteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Thomas Richardson, my exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said Thomas Richardson, my
exors, adñors, and assigns, and such others as I, the said Thomas Richardson,
my exors, admors, or assigns, should at any time agree with, and no others,
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,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "IMPROVE-
MENTS IN THE MANUFACTURE AND PREPARATION OF MAGNESIA AND, SOME OF ITS
SALTS;" in which said Letters. Patent is contained a proviso that I, the said
Thomas Richardson, shall cause a particular description of the nature of my
said Invention, and in what manner the same is to be. performed, by an.
instrument in writing under my hand and seal, to be inrolled in Her said
Majesty's High Court of Chancery within six calendar months next and

page_text: 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 large
appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Richardson, do hereby declare that the nature of my said Invention, 5
and the manner in which the same is to be performed, are fully described
and ascertained in and by the following statement thereof, that is to say :-
My Invention consists,―
First, of a mode of treating magnesian limestone with muriatic acid.
Secondly, my Invention consists partly of employing magnesia which has 1
been obtained by treating magnesian limestone with muriatic acid, when
operating on rough epsoms.
Another
part of
my Invention consists of employing magnesia obtained by
treating magnesian limestone with muriatic acid to produce a quantity of sul-
phate of magnesia, and at the same time improve the manufacture of artificial 1
alum.
Another part of my Invention consists of employing magnesia obtained by
treating magnesian limestone with muriatic acid as a means of purifying
rough epsoms or liquors containing impure sulphate of magnesia.
Another part of my Invention consists of employing magnesia obtained by 2
treating magnesian limestone with muriatic acid in purifying rough epsoms by
calcination.
Another part of my Invention consists of employing magnesia obtained by
treating magnesian limestone with muriatic acid, in order to produce sulphate
of magnesia from sulphate of iron or copperas liquors.
Another part of my Invention consists of making sulphate of magnesia
when manufacturing carbonate of soda.
Another part of my Invention consists of employing magnesia obtained by
treating magnesian limestone with muriatic acid in manufacturing carbonate
of magnesia of commerce and chloride of magnesia.
2
3
And in order that my Invention may be most fully understood and readily
carried into effect, I will proceed to describe the means pursued by me. It has
heretofore been proposed to employ muriatic acid to act on magnesian lime-
stone so as to dissolve the greater part of the lime, and it has also been
proposed to employ muriatic acid to dissolve the whole mass, and then to pre- 3
cipitate the magnesia. And I mention these matters in order that the nature
of the first part of my Invention may be more clearly defined and understood,
which consists of so employing muriatic acid to act on magnesian limestone
as to ensure the dissolving out of the lime, and yet to avoid as much as may be

page_text: dissolving the magnesia. In the present plan of conducting manufactories for
making alkali, large quantities of weak muriatic acid are allowed to run to
waste; and I prefer to use this acid for separating lime from maguesia; and it
is new, and constitutes part of my Invention, thus to employ such weak
muriatic acid, whether it be employed according to the first part of my
Invention or only for the most part to dissolve out the lime. I take
magnesian limestone, preferring such as I find by analysis to contain the
largest proportion of magnesia, and this I proceed to purify as follows: I
either commence the operation by causing the limestone to be burnt in the
usual way, and then I slake the calcined stone in pits, such as are at present
employed for washing out the lime with water by manufacturers of epsom
salts, or in any other convenient and suitable place. A quantity of muriatic
acid proportioned to the quantity of lime in the limestone, as herein after
described, is then run into the pits, and thoroughly agitated with the slaked
magnesian lime. After the acid is saturated by the lime, the insoluble portion
is allowed to subside, the supernatent liquor is run off, and the residual impure
magnesia repeatedly washed with water to remove all chloride of calcium and
other soluble matters. The proper proportion of acid to be employed in
dissolving the lime from calcined magnesian limestone is to be determined on
an analysis of the limestone. To every twenty-eight parts of lime as much
of muriatic acid is required as will contain thirty-seven parts of real muriatic
acid, preferring the weak muriatic acid, such as is now permitted to run waste;
but I use a slight excess of acid to ensure the removal of all the lime, the
pressure of which would be attended with loss in the subsequent operations;
or, secondly, I take the raw magnesian linestone (preferably grinding it to an
impalpable powder), either dry or with water, and I use the same acid and in
the same manner, but for every fifty parts of carbonate of lime present in such
mineral, only as much acid is required as will contain thirty-seven parts of real
muriatic acid. In this case, and for similar reasons, I propose to use a slight
excess of acid. The residual impure carbonate of maguesia may either be
used in that state, or may be calcined sufficiently to drive off the carbonic acid..
When I employ magnesia freed from lime as above explained by muriatic
acid, I can make pure sulphate of magnesia directly by using rather less
sulphuric acid than is necessary to completely neutralize the magnesia, and in
such case I employ a small quantity of charcoal, as hereafter mentioned..
I will now describe the second part of my Invention, which consists of
employing magnesia which has been separated from magnesia limestone by
dissolving out the lime more or less perfectly by means of muriatic acid.
It is well known that in the manufacture of alum in Yorkshire a product is

page_text: obtained called "rough epsoms," accompanied with which there is a quantity
of free sulphuric acid, which has heretofore been partially neutralized by
employing magnesian lime washed with water, which increases the quantity
of rough epsoms, but by reason of the quantity of lime present so large an
increase is not produced as is obtained by me when employing magnesia, and
which has been treated with muriatic acid, and which is freed or for the most
part freed from lime. And I would state that I prefer for this process the
use of magnesia produced according to the first part of my Invention, as it is
desirable to avoid as much as possible the presence of lime. I take the
magnesia or its carbonates, prepared as above, either free from lime or nearly
so, and mixed with water, and rendered into the form of a cream, and I run a
quantity of the same into the alum "mothers," such as are obtained in the
Yorkshire alum works. I thus partially neutralize the excess of sulphuric
acid, still, however, leaving a slight excess of acid which these "mothers"
contain, and I thus obtain a much larger production of "rough epsoms."
I will now describe the means resorted to by me in manufacturing sulphate
of magnesia when making artificial alum, by employing magnesia obtained
by treating magnesian limestone with muriatic acid. It is well known, in
manufacturing alum artificially, that there is a considerable excess of acid in
the liquors; and this part of my Invention consists of nearly neutralizing such
excess of acid by the employment of magnesia obtained by treating magnesian
limestone with muriatic acid, so as to obtain the magnesia free or nearly
free from lime. For this purpose I apply the magnesia previous to employing
the alkali in the manufacture of alum, using so much magnesia as is necessary
nearly to neutralize the excess of acid. The sulphate of magnesia, either
liquid or crystallized, is then obtained from the alum liquors (after crystallizing
out the alum) in the mode well known and practised in tho Yorkshire alum
works.
In a former Patent, granted to me on the Twenty-sixth day of January, One
thousand eight hundred and fifty, I described a process for purifying rough
epsoms, or liquors containing impure sulphate of magnesia, by employing an
excess of magnesia obtained by washing calcined magnesian linestone in
water. I have since discovered that that process may be greatly improved by
substituting or employing magnesia obtained by treating magnesian lime-
stone with muriatic acid, so that the magnesia may be free or nearly free
from lime. In carrying on this process I have found it desirable to employ
a very small quantity of animal or vegetable charcoal mixed with the cream
of magnesia, in order to prevent the formation of ferric or manganic
acid.

page_text: Now my
I will now describe my Invention, so far as it relates to purifying rough
epsoms by calcination. Heretofore it has been usual when purifying rough
epsoms by calcination to employ magnesian lime washed in water.
improvement of this process consists of employing magnesia obtained free or
nearly free from lime by treating magnesian limestone with muriatic acid.
In other respects the process of calcination is conducted as heretofore, using
so much of such magnesia as will fully neutralize the excess of acid, and also
the sulphuric acid combined with the substances present other than magnesia,
the quantity of acid being previously ascertained by analysis, as is well
understood.
I will now describe that part of my Invention which consists of producing
sulphate of magnesia from sulphate of iron or copperas liquors. In the
preparation of sulphate of iron by the slow oxidation of iron pyrites, an acid
sulphate of iron is obtained, from which I precipitate the oxide of iron by
magnesia prepared by employing muriatic acid as above, in slight excess.
The liquid which is separated after the precipitated oxide has subsided will
yield on evaporation in the usual way pure sulphate of magnesia. I also
employ a little charcoal in this case, for the same purpose as in the case of alum
mothers or liquor.
I will now describe that part of my Invention which relates to the making
of sulphate of magnesia when manufacturing carbonate of soda, which im-
provement consists of employing carbonate of magnesia obtained by treating
raw magnesian limestone by muriatic acid. In a Patent granted to
Mr. Peter Ward on the Sixth of July One thousand eight hundred and forty-
six, a process is described of manufacturing certain salts of soda and magnesia,
by the employment of native carbonates of magnesia. Now this part of my
Invention consists of employing carbonate of magnesia obtained by treating
magnesian limestone with muriatic acid in place of native carbonates of
magnesia. In other respects the process is conducted as in the Specification
enrolled to the said Patent.
I will now describe that part of my Invention which relates to manufac-
turing carbonite of magnesia of commerce and chloride of magnesia. I take
the magnesia prepared by employing muriatic acid, and having mixed it
largely with water so as to bring it to the consistence of milk, I run the same
into a series of Woulfe's bottles, or into a cistern made of wood or any other
suitable material, divided into compartments, closed alternately at the top and
bottom, until the whole are about two thirds full. I then cause a stream of
carbonic acid to pass through this milk of impure magnesia, until the greater
portion of the maguesia, being converted into bicarbonite of magnesia, enters

page_text: into solution. The whole contents are then run off into settlers, and the clear
supernatant liquid being gently heated to drive off the excess of carbonic acid,
a pure carbonate of magnesia precipitates, which may be collected and dried
in the manner now commonly practised by manufacturers of carbonate of
magnesia.
In manufacturing chloride of magnesia I take magnesia prepared by
the acid of muriatic acid from magnesian limestone, selected in this instance
as free from clay and insoluble matters as may be, which I dry at a tempe-
rature of about 100° Fahrenheit; it is then reduced to powder, which I employ
in place of the hydrate of lime in the present manufacture of bleaching
powder.
Having thus described the nature of my said Invention, I would have it
understood that I do not confine myself to the details herein given, so long as
the peculiar character of either part of my Invention be retained. And I
would have it understood that what I claim is,-
First, the mode herein described of manufacturing magnesia; and,
Secondly, I claim the means herein described of manufacturing salts of
magnesia.
In witness whereof, I, the said Thomas Richardson, have hereunto
set my hand and seal, this Tenth day of July, in the year of our Lord
One thousand eight hundred and fifty-two.