Year: 1888

page_text: Lamp-black, 8 parts.
First. The invention consists first of a process in which I take cryolite, corundum,
beauxite, common clay or other aluminous earth, ore or compound, and mixing the
same with proper parts of alum and common salt, place the same in a reverberatory
furnace or other suitably beated receptacle, and do thero thoroughly calcine or
roast the said ingredients and agents, and bring the product to the condition
suitable for the action of the fluxes or reducing agents employed in the second part
of my process.
This condition is reached when the iron contained within the mixture is oxidized
and eliminated along with the chlorine generated, and the silica and other impurities
disintegrated and separated from the oxide of aluminium, thereby leaving the latter
in a free state to be properly treated by the fluxes or reducing agents. The elimination
of the iron is effected as follows:-
By the calcination of the aluminous ores in presence of Alum and salt-Free Chlorine
is liberated and partly eliminates the iron by direct combination, probably being
volatilized as double chloride. But the larger proportion of iron present forms double
or compound salts with the silica combining with the Na-Ca &c. present at bases
and is eliminated in the form of a basic silicious slag.
Second. The roasting or calcining having been carried out as above indicated,
I take such quantity as I may need from the furnace and having allowed it to
cool, 1 mix it with certain parts of whiting, lamp-black and asbestos, and charge
the same into a suitable retort, which is then heated sufficiently and allowed to
remain so until all the gases have passed away, after which the retort is completely
closed and then allowed to remain at the same beat for two hours or thereabouts
when the charge is withdrawn and allowed to cool, when pure aluminium will be
found to have been cast down in buttons and globules.
After sifting the entire charge so as to separato the metallic portions, I place the
same in a crucible and melt them down and cast the metal into an ingot or other
desired form or forms.

page_text: By this method I can make aluminium of a high grade of purity at a very low cost
of production.
By the use of pulverized asbestos in this process, I prevent all slag from forming
and produce an ash whose porous character permits of the filtration and percolation of
the globules of aluminium as they are formed.
I reserve the right to use for the above described purposes, any equivalent sub-
stance or substances, for example, in the first process of calcining and roasting, I
may, instead of alum and common salt, use such equivalent mixtures or compounds
as manganese and muriatic acid or chloride of sodium and sulphuric acid, and in
my second process any suitable indestructible and porous materials, such as powdered
Mica, may be substituted for, or employed in conjunction with, asbestos.
I would have it understood that I do not confine myself to the precise ingredients
or agents and the proportions of the sume herein before designated so long as the
essential characteristics of my invention are retained.
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 :-
1. The process of obtaining aluminium from cryolite, corundum, beauxite or any
suitable aluminous earth or ore, by roasting or calcining the aluminium compound
from which the metal is to be obtained, mixed with alum and common salt thereby
oxidizing the iron and eliminating it along with the chlorine gas and disintegrating
and separating the silica or other impurities from the oxide.
2. The process of obtaining aluminium from any aluminous ore or earth by
roasting or calcining such ore or earth in the presence of alum and common salt or
their equivalent substantially as set forth.
3. The process of obtaining aluminium from aluminous ores and earths which
consists in mixing the same with suitable proportions of alum and common salt,
roasting the mixture until the iron in the ore or earth is oxidised, then removing the
mass or a portion thereof from the furnace and allowing it to cool, then mixing it
with a reducing agent or flux consisting of whiting, lamp-black, and powdered
asbestos or their equivalents, then charging the mixture into a suitable retort, then
beating said retort, drawing the charge and cooling it and finally sifting it and
separating out the metal, substantially as set forth.
Dated IIS ZIEM day of August 1888
Dated ™IS ZIEN day of Anonst. 1888
B. J. B. MILLS.
By Harris & Mills,
23, Southampton Buildings, Agents.
B. J. B. MILLS.
By Harris & Mills,
23, Southampton Buildings, Agents.