Improvements in the Manufacture of Cupels and Crucibles to be employed in the Refining of Metals.
Year: 1897

page_text: Improvements in the Manufacture of Cupels and Crucibles to be
employed in the Refining of Metals.
I, JOHN LASKEY DOBELL, of No. 46, Connaught Road, Harlesden, in the County
of Middlesex, Electrician, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in the manufacture of cupels and
crucibles to be employed in the refining of metals.
Cupels, according to the method of manufacture usually adopted, are formed of
bone ash which is a somewhat expensive material for the purpose, whilst crucibles
have generally been formed of plumbago and clays of various kinds, and the object
of the present invention is to produce a more durable article at a cheaper rate than
heretofore.
In carrying the invention into effect, a quantity of magnesite, which has be
previously calcined and ground to a finely divided state, is moistened with a
saturated solution of boracic acid in water or in spirit and water or with a quantity
of horacic acid dissolved in spirit, and the mass is then kneaded or mixed into a
stiff paste or dough after which it is shaped to the form desired to be given to the
cupel or crucible, the article is then dried by any suitable means, and, in some
cases, is fired or baked in a muffle or furnace and caused or allowed gradually to
cool, after which it is ready for use.
By the means hereinbefore described, and at a reduced cost a cupel or crucible is
obtained which will effectually resist the action of heat and answer all the purposes
of the more expensive articles herein before referred to.
Dated this 30th day of April 1807
VAUGHAN & SON,
Agents for the Applicant.
Improvements in the Manufacture of Cupels and Crucibles to be
employed in the Refining of Metals.
I, JOHN LASKEY DOBELL, of No. 46, Connaught Road, Harlesden, in the County
of Middlesex, Electrician, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
-
My said invention relates to improvements in the manufacture of cupels and
crucibles to be employed in the refining of metals.

page_text: Cupels, according to the method of manufacture usually adopted, are formed of
bone ash, which is a somewhat expensive material for the purpose, whilst crucibles
have generally been formed of plumbago and clays of various kinds and the object
of the present invention is to produce a more durable article at a cheaper rate than
heretofore.
In carrying the invention into effect, a quantity of magnesite, which has been
previously calcined and ground to a finely divided state, is moistened with a
saturated solution of boracic acid in water or in spirit and water, or with a quantity
of boracic acid dissolved in spirit, and the mass is then kneaded or mixed into a
stiff paste or dough, after which it is shaped to the form desired to be given to the
cupel or crucible, the article is then dried by any suitable means, and, in some
cases, is fired or baked in a muffle or furnace and caused or allowed gradually to
cool, after which it is ready for use.
The baking should be effected in an atmosphere free from silica and other
metallic impurities, or, the article to be baked may be embedded in powdered
magnesia, dolomite or lime, or, the desired object may be attained by conducting
the baking within a furnace constructed of magnesia bricks.
The calcined magnesite may be slaked and dried after having been ground.
In cases where it is desired to increase the porosity of the magnesite pot, a
quantity of sawdust, bran, flour or other similar material is mixed with the
magnesite, and, in this case, the article must be fired or baked to carbonise or destroy
the sawdust, bran or other material.
By the means herein before described and at a reduced cost, a cupel or crucible is
obtained which will effectually resist the action of heat and answer all the purposes
of the more expensive articles hereinbefore referred to.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
A cupel or crucible to be employed in the refining of metals formed of calcined
magnesite reduced to a fine state of division, moistened with a solution of boracic
acid and water or spirit and water or with a quantity of boracic acid dissolved in
spirit, then made into a stiff paste or dough and shaped to the required form of the
article to be produced, and afterwards dried, and, if desired, baked or fired, in
manner substantially as herein described and for the purpose stated.
Dated this 27th day of Januar 1898
VAUGHAN & SON,
Agents for the Applicant.