IMPROVEMENTS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said William Gentles at the Office
of the Commissioners of Patents on the 15 February 1882.
WILLIAM GENTLES of Widnes in the County of Lancaster
THE MANUFACTURE OF SULPHATE OF ALUMINA."
"IMPROVEMENTS IN
The said invention refers to the separation of iron and free acid from Sulphate
of Alumina and at same time affecting a bleaching action on the solution.
In carrying out the process a solution of Chlorate of Lime is added in equivalent
quantity sufficient to effect by double decomposition the precipitation of the acid
of the iron salt and at same time forming a very soluble chloride of iron: a slight
excess of chlorate of lime is desirable so as to effect a bleaching action on the
solution and at same time the major portion of the free Sulphuric Acid may be
thus precipitated. The solution is now allowed to rest for sometime so as to
deposit the Lime Sulphate, or it may be brought to boiling before settling, so as to
facilitate deposition of the lime sulphate. The said well settled solution may now
be concentrated to a temperature sufficient on cooling to produce a gelatinous mass
from which the very soluble chloride of iron may be along with any traces of free
acid expelled, or expressed by an Hydro extractor or submitted to pressure by any
of the already long known methods of expression or expulsion or I may use a
solution of bleaching powder to effect the decomposition herein before described.

page_text: SPECIFICATION in pursuance of the Conditions of the Letters Patent and of
an Order of the Lord Chancellor filed by the said William Gentles in the
Great Seal Patent Office on the 19 August 1882.
WILLIAM GENTLES, of Widnes in the County of Lancaster
THE MANUFACTURE OF SULPHATE OF ALUMINA."
"IMPROVEMENTS IN
The said invention refers to the separation of iron and free acid from sulphate
of Alumina and at same time effecting a bleaching action on the solution.
In carrying out the process, a well mixed, and turbid solution of chlorate of lime
such as that formed by chlorinating milk of lime in the manufacture of Chlorate of
Potash and containing Chloride of Calcium is added to a crude solution of sulphate
of alumina to form a chloride of iron by double decomposition with the existing
sulphate of iron. The free lime contained in the turbid solution of lime chlorate
combines with the free sulphuric acid and is precipitated as sulphate of lime. The
solution is now allowed to rest for some time so as to deposit the line sulphate or
it may be brought to boiling before settling so as to facilitate deposition of the
lime sulphate. The said well-settled solution may now be concentrated to a
temperature sufficient on cooling to produce a Semi-Crystalline mass from which
the very soluble chloride of iron may be, along with any traces of free acil,
expelled or expressed by a hydro-extractor or submitted to pressure by any of the
already long known methods of separating a fluid from a solid. The fluid portion
is now transferred to a lead or iron pan, or suitable furnace, and concentrated to a
density, so that on being put on a setting plate, a high strength, or rich-in-alumina
cake may be produced, or the operation may be carried out in a furnace till
nearly all the water of hydration and composition is expelled, or the cake from
the setting plate may be introduced into a suitable vessel of iron or fire clay
such as a gas retort, or a furnace and nearly all the water of hydration and
composition expelled by heat so as to produce an almost white anhydrous sulphate
of aluminu of very high strength well suited for transport.
While mentioning only crude chlorate of lime containing Chloride of Calcium
I am well aware that the chlorates of the other alkaline earths will to some extent
answer the same purpose but they are so much more expensive that their
application would only be a colourable and expensive imitation of my invention
for the purpose of effecting the same result.
Having now described my invention and the best mode known to me of carrying
it into effect I wish it to be understood that what I believe to be new and claim
protection for under the Letters Patent is:-
First In the manufacture of sulphate of alumina the purification of the same
from iron by converting the iron salt into chloride of iron, and extracting the same
by mechanical means substantially as described―
Second The purification of crude sulphate of alumina from salts of iron by
decomposition with chlorate of lime containing Chloride of Calcium.
In witness whereof I the said William Gentles have hereunto set my hand
and seal this Tenth day of August in the year of our Lord, one thousand
eight hundred and sighty two