A New Method of Treating Borates of Lime and Boracite with a view to the Manufacture of Borax and of other Borates.
Year: 1890

page_text: D.te o Application (in United Kingdom), 17th Feb., 1890
Complete Specification Left, 17th Nov., 1890-4ccepted, 31st Jen.. 1361
PROVISIONAL SPECIFICATION.
A New Method of Treating Borates of Lime and Boracite with a view
to the Manufacture of Borax and of other Borates.
THE BORAX COMPANY LIMITED of No. 41 Eastcheap in the City of London,
and No. 66 Rue de la Chaussée d'Antin Paris in the Republic of France, Miners
and Refiners do hereby declare the nature of this invention to be as follows:-
Hitherto borax has been obtained either by treating carbonate of soda by boracic
acid, or by decomposing borate of lime by carbonate of soda and thus forming a
basic borate of soda, which was then converted into the biborate (borax) by means
of a current of carbonic acid (carbonic anhydride).
The latter process is more economical than the former but it presents two
objections.
In the first place, the sulphate of lime, which is always found mixed with the
borate of lime, is in the presence of the carbonate of soda, converted into sulphate
of soda, which accumulates rapidly in the mother liquors, and soon renders either
their purification or their evacuation necessary so that a loss of borax ensues.
In the second place to obtain a satisfactory decomposition of the borate of lime
it is essential that the density of the liquors should not be superior to 20° or 25°
Beaumé.
The object of our invention is to obviate the above mentioned disadvantages and
to render the manufacture of borax and of other borates more economical.
Our process consists in the first place of a preliminary purification of the borate
of lime obtained by one or more washings of the ore in a solution containing
carbonate of soda in quantity equivalent to the sulphate of line to be eliminated.
The liquor is then drawn off, and carries with it the sulphate of soda that has
been produced leaving a mixture of borate and of carbonate of lime.
To this purified mass there is then added the quantity of carbonate of soda
necessary to convert the borate of lime into a basic borate of soda, and the mass
diluted just sufficiently to enable it to be poured is introduced into an air tight
metallic recipient capable of supporting a pressure of several atmospheres which is
then connected with a boiler.
The steam on arriving in the mass throws it into violent agitation; the pressure
and in consequence the temperature rises rapidly and after a comparatively short
interval of time all the borate of lime is converted into a basic borate of soda and
into carbonate of lime which is insoluble.
It would be possible to obtain the same result without making use of a boiler, if
the recipient were placed directly on to a furnace but in this case it would be
necessary to furnish the recipient with an agitator by means of which the solid
matter could be maintained in suspension up to the moment of liquefaction.
Whichever method be adopted when once this treatment has been completed
the contents of the recipient whose density is about 60° Beaumé are forced by the
pressure into a vat where the amount of boracic acid necessary to convert the

page_text: basic borate of soda into borax is added and in which they are mixed with the
mother liquors of preceding crystallizations of borax.
The temperature of the liquors is then raised to the boiling point and a separa-
tion is then effected either by decantation or by filtration between the carbonate of
lime and the clear liquid which is then sent into the crystallizing vats.
Dated this 17th day of Wahmary 1900
AYRTON & THOMAS,
Agents for the Applicants.
COMPLETE SPECIFICATION.
A New Method of Treating Borates of Lime and Boracite with a view
to the Manufacture of Borax and of other Borates.
We THE BORAX COMPANY LIMITED of No. 41 Eastcheap in the City of London,
and No. 66 Rue de la Chaussée d'Antin Paris in the Republic of France Miners
and Refiners do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
Hitherto borax has been obtained either by treating carbonate of soda by boracic
acid, or by decomposing borate of lime by carbonate of soda, and thus forming a
basic borate of soda, which was then converted into the biborate (borax) by means
of a current of carbonic acid (carbonic anhydride).
The latter process is more economical than the former but it presents two
objections.
In the first place, the sulphate of lime which is always found mixed with the
borate of lime, is, in the presence of the carbonate of soda, converted into sulphate of
soda, which accumulates rapidly in the mother liquors, and soon renders either their
purification or their evacuation necessary so that a loss of borax ensues.
In the second place to obtain a satisfactory decomposition of the borate of lime
it is essential that the density of the liquors should not be superior to 20° or 25°
Beaumé.
The object of our invention is to obviate the above mentioned disadvantages and
to render the manufacture of borax and of other borates more economical.
Our process consists in the first place of a preliminary purification of the borate
of lime obtained by one or more washings of the ore in a solution containing
carbonate of soda, in quantity equivalent to the sulphate of lime to be eliminated.
The liquor is then drawn off, and carries with it the sulphate of soda that has
been produced, leaving a mixture of borate and of carbonate of lime. To this
purified mass there is then added the quantity of carbonate of soda necessary to
convert the borate of lime into a basic borate of soda, and the mass diluted just
sufficiently to enable it to be poured, is introduced into an air tight metallic,
recipient, capable of supporting a pressure of several atmospheres, which is then
connected with a boiler.
The steam on arriving in the mass throws it into violent agitation; the pressure
and in consequence the temperature rises rapidly and after a comparatively short
interval of time all the borate of lime is converted into a basic borate of soda and
into carbonate of lime which is insoluble.
It would be possible to obtain the same result without making use of a boiler, if
the recipient were placed directly on to a furnace but in this case it would be
necessary to furnish the recipient with an agitator by means of which the solid.
matter could be maintained in suspension up to the moment of liquefaction.
Whichever method be adopted, when once this treatment has been completed
the contents of the recipient, whose density is about 60° Beaumé are forced by
the pressure into a vat where the amount of boracic acid necessary to convert the
basic borate of soda into borax is added and in which they are mixed with the
mother liquors of preceding crystallizations of borax.

page_text: The temperature of the liquors is then raised to the boiling point and a separation
is then effected either by decantation or by filtration between the carbonate of lime
and the clear liquid which is then sent into the crystallizing vats.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is :-
1. In a process for manufacturing borax from borates of lime and boracite, the
preliminary purification of the borate and elimination of the foreign matters and
salts which accompany it and more particularly of the sulphate of lime substantially
as described.
2. The treatment of borate of lime substantially as described, at a high pressure
in view to its conversion into borax.
Dated this 17th day of November 1890
AYRTON & THOMAS,
Agents for the Applicants.