THE MANUFACTURE OF REFRACTORY MATERIAL BY IMPROVED PROCESSES OR METHODS OF TREATING DOLOMITE
Year: 1880

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
"THE MANUFACTURE OF REFRACTORY MATERIAL BY IMPROVED PROCESSES
OR METHODS OF TREATING DOLOMITE." A communication from abroad by
Alfred Braconnier, of Paris, France.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 22nd November 1880.
WILLIAM ROBERT LAKE,. of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. THE MANUFACTURE OF REFRACTORY MATERIAL
BY IMPROVED PROCESSES OR METHODS OF TREATING DOLOMITE." [A communi-
cation from abroad by Alfred Braconnier, of Paris, France.]
This Invention relates to the manufacture of refractory material by improved
processes or methods of treating natural calcined dolomite rich in magnesia.
It is well known that such materials or products are durable in proportion to
the quantity of magnesia they contain.
My Invention consist chiefly in extracting from calcined dolomite any desirable
portion of the lime contained therein by means of a solution of hydro-chlorate of
ammonia, which contains a suitable proportion of this salt. The lime only is
dissolved, and the magnesia with the foreign matters contained in the dolomite
remains insoluble. The great advantages offered by my Invention are, first, that I
carry the enrichment in magnesia of the calcined dolomite to any limit that may
be desirable, and that the precipitate of magnesia which I obtain is not viscous
like the hydrate of magnesia extracted by precipitating chloride of magnesium, but
is pulverulent, and very easily washed and filtered.
According to my Invention, when using hydrochlorate of ammonia liquor which
has been employed in the manufacture of soda, I proceed as follows, that is to
sayTo this solution or liquor, which contains bicarbonate of soda and carbonic
acid, I first add slaked lime in a proportion exactly sufficient to saturate the free
carbonic acid and to reduce the bicarbonate of soda to a simple carbonate; then,

page_text: without decanting or filtering, I add to the same liquor a certain quantity of a
solution of chloride of calcium produced in previous operations in such quantity as
will be exactly sufficient completely to transform the carbonate of soda into
chloride of sodium. The liquor is then allowed to settle, and will be ready for use
after decantation and filtration. The liquor so purified is then treated with a
suitable proportion of calcined dolomite; in this operation the ammonia becomes
liberated, and is separately collected. The enriched dolomite remains insoluble,
and the liquid which remains after decantation, washing, and filtration, contains
the dissolved lime in the form of chloride of calcium.
But for the application of my process it is not necessary to use hydrochlorate of
ammonia liquor which has been produced in the manufacture of soda, and from
which the bicarbonate of soda has been eliminated; in other words, my process is
not necessarily connected with the manufacture of soda.
The residuum of the operation performed in practising this Invention is a
solution of chloride of calcium. Instead of throwing this chloride away I introduce
carbonic acid with the ammonia which is liberated during the above described
process; thus hydrochlorate of ammonia is again formed, whilst at the same time
carbonate of lime, which is easily washed and separated, is precipitated.
This method of incessantly regenerating the hydrochlorate of ammonia is of
great importance, as in many cases soda-manufacturers might refuse either to enrich
natural calcined dolomite themselves, or to part with their hydro-chlorate, whilst
they would not refuse to get rid of a portion of their chloride of calcium,
In all cases it will be easy to obtain the small quantity of ammonia and of
hydro-chloric acid required to replace the loss produced by the aforesaid process, as
by all other continuous processes.
By practising this Invention there will be no difficulty in preparing pure
magnesia, if only the dolomite itself be pure, and it will be readily seen that this
process, even as regards the preparation of magnesia, is entirely novel.
The fundamental idea applied in the processes hitherto in use for the above
named purpose is, first, to obtain a solution of chloride of magnesium, then to
precipitate the dissolved magnesia by calcined dolomite. In this manner a preci-
pitate is obtained which is viscous, difficult to wash, decant, and filter, and the
manipulation of which entails very considerable expense, whilst that obtained by
my said process is pulverulent and capable of being treated with facility.
Furthermore, the processes which have been hitherto used will not produce pure
magnesia, as the treatment of residues from soda-manufacture by calcined dolomite
as ordinarily practised must necessarily give a solid precipitate of carbonate of
lime. It is also known to those acquainted with the manufacture of soda that the
utilization of the residues from this manufacture by the ordinary processes above
referred to will always give magnesia containing 15% of caustic lime.
о

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the
21st May 1881.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "THE MANUFACTURE OF REFRACTORY MATERIAL
BY IMPROVED PROCESSES OR METHODS OF TREATING DOLOMITE." A communi-
cation from abroad by Alfred Braconnier, of Paris, France.
This Invention relates to the manufacture by improved processes or methods of
treating natural calcined dolomite of refractory materials rich in magnesia..
It is well known that such materials or products are durable in proportion to
the quantity of magnesia they contain.
My Invention consists chiefly in extracting from calcined dolomite any desirable
portion of the lime contained therein by treating such dolomite with a solution of
hydrochlorate of ammonia, which contains a suitable proportion of this salt, and
may either be pure or produced in some manufacturing process. The lime only is
dissolved, and the magnesia, with the foreign matters contained in the dolomite,
remains insoluble. The great advantages offered by my Invention are, first, that I
carry the enrichment in magnesia of the calcined dolomite to any extent that may
be desirable, and that the precipitate of magnesia which I obtain is not viscous like
the hydrate of magnesia extracted by precipitating chloride of magnesia, but is
pulverulent and very easily washed and filtered.
According to my Invention, when using hydrochlorate of ammonia liquor which
has been employed in the manufacture of soda, I proceed as follows, that is to
say To this solution or liquor, which contains bicarbonate of soda and carbonic
acid, I first add slaked lime in a proportion exactly sufficient to saturate the free
carbonic acid and to reduce the bicarbonate of soda to a simple carbonate; then,
without decanting or filtering, I add to the same liquor a certain quantity of a
solution of chloride of calcium produced in previous operations in such quantity
as will be exactly sufficient to completely transform the carbonate of soda into
chloride of sodium. The liquor is then allowed to settle, and will be ready for use
after decantation and filtration. The liquor so purified is then treated with a suitable
proportion of calcined dolomite. In this operation the ammonia becomes liberated,
and is separately collected. The enriched dolomite remains insoluble, and.the.
liquid which remains after decantation, washing, and filtration contains the dissolved
lime in the form of chloride of calcium.
But for the application of my process it is not necessary to use hydrochlorate of
ammonia liquor which has been produced in the manufacture of soda, and from
which the bicarbonate of soda has been eliminated; in other words, my process is
not necessarily connected with the manufacture of soda.
The residuum of the operation performed in practising this Invention is a
solution of chloride of calcium. Instead of throwing this chloride away I introduce
carbonic acid with the ammonia which is liberated during the above described
process; thus hydrochlorate of ammonia is again formed, whilst at the same time
carbonate of lime, which is easily washed and separated, is precipitated.
This method of continually regenerating the hydrochlorate of ammonia is of
great importance, as in many cases soda manufacturers might refuse either to enrich
natural calcined dolomite themselves, or to part with their hydrochlorate, whilst
they would not refuse to get rid of a portion of their chloride or calcium.
In all cases it will be easy to obtain the small quantity of ammonia and of
hydrochloric acid required to replace the loss produced by the aforesaid process, as
by all other continuous processes.

page_text: By practising this Invention there will be no difficulty in preparing pure magnesia
if only the dolomite itself be pure, and it will be readily seen that this process, even
as regards the preparation of magnesia, is entirely novel.
The fundamental idea applied in the processes hitherto in use for the above
named purpose is, first, to obtain a solution of chloride of magnesium, then to
precipitate the dissolved magnesia by calcined dolomite. In this manner a preci-
pitate is obtained which is viscous, difficult to wash, decant, and filter, and the
manipulation of which entails very considerable expense, whilst that obtained by
my said process is pulverulent and capable of being treated with facility.
Furthermore, the processes which have been hitherto used will not produce pure
magnesia, as the treatment of residues from soda-manufacture by calcined dolomite
as ordinarily practised, must necessarily give a solid precipitate of carbonate of
lime. It is also known to those familiar with the manufacture of soda that the
utilization of the residues from this manufacture by the ordinary processes above
referred to will always give magnesia containing 15% of caustic lime.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
First. The above described process for treating natural calcined dolomites for the
production of refractory materials rich in magnesia, which process consists essen-
tially in extracting (without dissolving any of the magnesia) by means of hydro-
chlorate of ammonia and in the form of a soluble salt, the lime contained in the
dolomite, the hydrochlorate of ammonia being either specially made in a pure
condition, or the product of any manufacturing process purified before being used
for the purpose of my Invention.
Second. The special method above described of treating dolomite with hydro-
chlorate of ammonia liquor produced in the manufacture of soda.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twenty first day of May, in the year of our Lord One
thousand eight hundred and eighty-one.
DANT