IMPROVEMENTS IN THE MANU- FACTURE OF CERTAIN SALTS OF MAGNESIA AND A RED COLORING MATTER
Year: 1853

page_text: LETTERS PATENT to Thomas Richardson, of Newcastle-upon-Tyne,
Manufacturer, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF CERTAIN SALTS OF MAGNESIA AND A RED COLORING
MATTER."
Scaled the 19th August 1853, and dated the 14th June 1853.
PROVISIONAL SPECIFICATION left by the said Thomas Richardson
at the Office of the Commissioners of Patents, with his Petition,
on the 14th June 1853.
I, THOMAS RICHARDSON, of Newcastle-upon-Tyne, Manufacturer, do
hereby declare the nature of the Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF CERTAIN SALTS OF MAGNESIA AND A RED COLORING
MATTER," to be as follows:-
This Invention consists of manufacturing carbonate of magnesia and
sulphate of magnesia, and also a red coloring matter. To manufacture
carbonate of magnesia, impure carbonate or hydrate of magnesia is
diffused in water, into which carbonic acid obtained from coke or other

page_text: source is caused to pass. Sulphate of magnesia containing sulphate of
iron, or sulphate of iron itself, is heated with fluor spar to obtain sulphate
at mainasia and a red coloring matter.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Richardson in the Great Seal Patent
Office, on the 10th December 1853.
"
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS RICHARDSON, of Newcastle-upon-Tyne, Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, hearing date the Fourteenth day of June, in the year
of our Lord One thousand eight hundred and fifty-three, in the six-
teenth of Her reign, did, for Herself, Her heirs and successors,
year
give and grant unto me, the said Thomas Richardson, Her special
licence that I, the said Thomas Richardson, my executors, adininis-
trators, and assigns, or such others as I, the said Thomas Richardson,
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, 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 CERTAIN SALTS OF MAGNESIA
AND A RED COLORING MATTER," upon the condition (amongst others) that
1, the said Thomas Richardson, 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 per-
formed, 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 Thomas Richardson, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof (that is to say):

page_text: This Invention consists in diffusing impure carbonate or hydrate of
magnesia in water, and passing carbonic acid obtained from coke or
other sources through the same. After allowing the impurities to sub-
side, the clear supernatant liquid is drawn off and boiled, or otherwise
treated, to obtain the ordinary carbonate of magnesia.
And my Invention also consists in heating sulphate of iron, or impure
sulphate of magnesia containing sulphate of iron, with ground fluor
spar, and by such means to obtain coloring matter and sulphate of
magnesia.
The impure hydrate of magnesia, which is a waste product in what is
known as Ward's process of carbonating soda ash, is especially
adapted for the manufacture of carbonate of magnesia by my process;
but any other impure hydrate or carbonate of magnesia free from lime,
or nearly so, such as magnesite, may be employed.
I take any of these forms of magnesia, and diffuse them through water
so as to form a cream or milk-like liquid, which I run into a large soda
water machine, where I pump in carbonic acid, in the same manner as
when making soda water. Or I partially fill a wooden box, divided
into cells by partitions running from the top and bottom alternately
with this milk-like liquid, and by means of a steam jet or air pump
worked by suitable machinery I draw a stream of carbonic acid through
the whole series of compartiments from a furnace filled with coke or
charcoal. When the liquid becomes saturated with bicarbonate of
magnesia, or stands at 5° to 11° on Twaddell's hydrometer, it is drawn
off, and after standing about an hour a small quantity of a cream of
magnesite is gradually added, which I find carries down all oxide of
iron and other impurities, leaving a clear pure solution of bicarbonate
of magnesia.
This solution is heated to expel the excess of carbonic acid when the
carbonate precipitates, and is collected and treated in the usual way;
or a quantity of pure magnesia in suspension in water is added, until
the whole is precipitated as carbonate of magnesia.
The furnace which I employ for producing carbonic acid is filled
with coke or charcoal, and is supplied with air through an opening at
the bottom, and another higher up on a level with the top of the fuel.
The air may be drawn through by means of a jet of steam or otherwise,

page_text: or forced forwards by a blowing cylinder or fan blast so regulated by
valves or dampers that the supply of air entering at the upper opening
shall be a little more than sufficient to convert all the carbonic oxide
into carbonic acid so as to economise the fuel, and render the action of
the gas more energetic on the milk of magnesia. Carbonic acid
obtained from any other source equally answers my purpose.
The character of the furnace is shewn in elevation in Figure 1, in
section in Figure 2, and the plan in Figure 3. a, represents a fan
blast, which may be replaced by a blowing cylinder. b, and c, are the
two pipes which convey the air above and below the coke or charcoal d,
and the relative quantities are regulated by the valves e, and f. The
carbonic acid passes off at g. The ashes and scars are removed at h,
and the coke is thrown in at the door i. Grates may be employed, as
shown at h, when the ashes do not scar.
At present, in some manufactories, the impure sulphate of magnesia is
calcined at a high temperature in order to convert the iron and man-
ganese into insoluble oxides. This operation is attended with consider-
able loss of sulphate of magnesia, even with the addition of magnesia to
the impure Epsoms previous to calcination. To obviate this loss I
employ one part of fluor spar for every four parts of the sulphates of
iron or manganese present in the impure Epsomis, together with the
ordinary quantity of magnesia and calcine, this mixture at a very low
temperature. A double decomposition ensues between the metallic
sulphates and the fluor spar, while the metals are rapidly peroxidized
and rendered insoluble. The calcined materials are lixiviated and
treated in the usual way for obtaining pure Epsom salts, while the
metallic oxides may be employed as a coloring material. Fluor spar
may also be calcined with the sulphate of iron in the manufacture of
Venetian red. I employ the copperas and fluor spar in the same pro-
portions as already named, and so much less gypsum as corresponds
with that produced from the fluor spar during the operation, the other
materials of the batch remaining the same. The operation is conducted
in precisely the same manner as at present, but I find the oxidation is
so much more rapid and perfect that one furnace turns out as much
crude Venetian red as three without the use of the fluor spar.
Having thus described the nature of my said Invention, and the

page_text: manner of performing the same, I would have it understood in respect
to the first part of my Invention that I do not claim dissolving hydrate
or carbonate of magnesia in general by the employment of carbonic
acid and water, nor the precipitation of carbonate of magnesia from its
solution in the form of a bicarbonate, either by heat or magnesia, as
above described, as these have been long known to and practised by
chemists. But I claim the treating impure magnesia, such as results from
Ward's process, or magnesite, or such like mineral, with carbonic acid
and water, as described above, in the manufacture of pure carbonate
magnesia. I also claim the use of fluor spar and sulphate of iron for
making a red coloring matter, either alone, or in connection with the
preparation of pure sulphate of magnesia.
In witness whereof, I, the said Thomas Richardson, have here-
unto set my hand and seal, this Second day of December, in
the year of our Lord One thousand eight hundred and fifty-
three.
Witness,
M. STENHOUSE,
THOMAS RICHARDSON. (L.S.)
20, Sandhill,
Newcastle-on-Tyne.