Improvements in the Manufacture of Aluminium and Alloys of Aluminium.
Year: 1888

page_text: Date of Application, 10th Apr., 1888
Complete Specification Left, 7th Feb., 1889
Complete Specification Accepted, 9th Mar., 1889
Improvements in the Manufacture of Aluminium and Alloys of
Aluminium.
-
We SAMUEL PEARSON of No. 196 Pitsford Street Birmingham in the County of
Warwick Engineer and Chemist and JAMES LIDDON of No. 13 Corporation Street
Birmingham aforesaid Stock Broker and JAMES HENRY PRATT of No. 13 Corporation
Street Birmingham aforesaid Stock Broker do hereby declare the nature of this
Invention to be as follows:-
In the manufacture of aluminium according to the said invention we take cryolite
in powder and to one hundred parts by weight of the said powdered cryolite we add
from seventy to one hundred parts by weight of powdered carbonate of lime and from
one to ten parts by weight of powdered carbon. We mix these ingredients intimately
and heat them to bright redness but below the fusing point in a furnace or in a
melting pot. By the reaction which takes place fluoride of calcium and metallic
aluminium are produced the aluminium being diffused through the fluoride of
calcium.
IJ
Where the mixture is heated in a crucible or melting pot a melting pot of carbon
or a melting pot lined with carbon may be employed in which case the powdered
carbon hereinbefore referred to may be omitted.
In order to separate the free aluminium from the fluoride of calcium the mass
obtained in the manner described is heated in a distillatory apparatus and the
aluminium distilled over. Or the mass may be heated with an easily fused flux and
the particles of aluminium thereby allowed to collect and cohere.
In order to make the alloy of aluminium and copper called aluminium bronze we
take the mass of fluoride of calcium and aluminium produced as bereinbefore
described and powder it and wash it with water and dry it. This powder is added to
copper melted either in an open furnace or in a melting pot the mixture being stirred
a few minutes. Or the powdered mass may be mixed with granulated copper and
the mixture gradually heated to fusion. In each case an alloy of aluminium and
copper is produced the fluoride of calcium constituting a liquid flux on the surface of
the melted alloy.

page_text: Or any other metal or mixture of metals may be substituted for metallic copper in
either of the two last described processes when an alloy of aluminium with the metal
or mixture of metals employed will be produced.
In place of the carbonate of lime herein before referred to an equivalent proportion of
quick lime or chloride of calcium may be employed. In either of these cases we
employ from forty to sixty parts by weight of carbon to one hundred parts by weight
of cryolite...
Dated this 10th day of Anvil 1000
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Aluminium and Alloys of
Aluminium.
We SAMUEL PEARSON of No. 196 Pitsford Street Birmingham in the County of
Warwick Engineer and Chemist and JAMES LIDDON of No. 13 Corporation Street
Birmingham aforesaid Stock Broker and JAMES HENRY PRATT of No. 13 Corporation
Street Birmingham aforesaid Stock Broker do hereby declare the nature of the
said Invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The said invention consists of the improvements hereinafter described in the manu-
facture of aluminium and alloys of aluminium the said invention being especially
applicable to the manufacture of alloys of aluminium.
In manufacturing aluminium according to the said invention we take cryolite in
fine powder and to one hundred parts by weight of the said powdered cryolite we
add fifty parts by weight of bauxite or artificially prepared hydrate of alumina or
kaolin fifty parts by weight of chloride of calcium or carbonate of lime fifty parts by
weight of carbon preferably ground coke or anthracite coal. All the ingredients
added to the finely powdered cryolite may be either in a coarse or fine powder.
The above named materials in the proportions specified are intimately mixed and
heated to low redness or to such a temperature as will effect the incipient fusion
but not the complete fusion of the mixture. The heating of the mixture is effected
in an open furnace or in a crucible or melting pot made of or containing carbon or
lined with carbon. When a carbon crucible or a crucible lined with carbon is
employed the carbon which we have described as one of the ingredients to be mixed
with the cryolite may be in part omitted. The heating of the mixture to the
temperature above referred to is continued for about two hours.

page_text: By the treatment described the cryolite and the other aluminium compound mixed
with it are decomposed the metallic aluminium being diffused through the incipiently
fused mixture in the form of minute globules.
In order to separate the metallic aluminium from the fluoride of calcium and saline
matter with which it is mixed we add after the described heating of the mixture
chloride of potassium and chloride of sodium or common salt twenty five parts of
each being added to the semi-fused mixture obtained in the way described. After the
addition of the chloride of potassium and chloride of sodium the temperature of the
melting pot and its contents is raised to bright redness. The added chlorides of
potassium and sodium produce with the saline matter in which the particles of
aluminium are suspended a liquid flux from which the said particles can separate and
collect in a mass. Owing however to the low specific gravity of aluminium it is
difficult to separate it by subsidence and we prefer to separate it by a distillatory
process. That is we prefer to make with the aluminium obtained as described an
alloy with zinc as hereinafter described and by subjecting the said alloy of aluminium
and zinc to distillation thereby drive off the zinc and leave the aluminium behind.
In order to make the alloy of aluminium and copper called aluminium bronze we
take the mass of fluoride of calcium and aluminium produced as hereinbefore described
and powder it and wash it with water and dry it. This powder is added to copper
melted either in an open furnace or in a melting pot the mixture being stirred a few
minutes. Or the powdered mass may be mixed with granulated copper and the
mixture gradually heated to fusion. In each case an alloy of aluminium and copper
is produced the fluoride of calcium constituting a liquid flux on the surface of the
melted alloy.
Or the metal or metals to be alloyed may be added to the mixture before heating
and when melted stirred as described chloride of sodium or common salt being added
as a flux in cases where the metal is readily fusible.
Or any other metal or mixture of metals may be substituted for metallic copper in
either of the two last described processes when an alloy of aluminium with the
metal or mixture of metals employed will be produced.
In order to obtain unalloyed aluminium we form an alloy of aluminium with zinc
in the way described of forming an alloy of aluminium and copper the metal zine
being substituted for copper and from the said alloy we obtain unalloyed aluminium
either by the use of a distillatory apparatus or by simply heating the alloy till the
zinc has been volatilized.
Although we prefer to effect the decomposition of the cryolite or compound of
aluminium on which we operate by the use of chloride of calcium yet other calcareous
compounds such for example as carbonate of lime or unslaked quick lime may be
employed in place of chloride of calcium. In place of chloride of calcium chloride of
barium or chloride of strontium may be employed. We prefer however chloride of
calcium or the other calcium compounds indicated to the compounds of barium or
strontium.
Having described the best methods with which we are acquainted of carrying the
said invention into effect we wish it to be understood that we do not limit ourselves
to the proportions herein before given of the different ingredients we employ as the
proportions may be varied within considerable limits without affecting the results
obtained.
Having now particularly described and ascertained the nature of the said inven-
tion and the manner in which the same is to be performed we declare that we claim
as the said invention of "Improvements in the manufacture of aluminium and alloys
of aluminium" :-
First The manufacture of aluminium by treating cryolite either alone or mixed
with natural or artificial hydrate of alumina by mixing cryolite or a mixture of
cryolite and hydrate of alumina with chloride of calcium or carbonate of lime or
unslaked quicklime or with chloride of barium or chloride of strontium and carbon
and first heating the mixture to incipient fusion thereby effecting the decomposition

page_text: of the aluminium compound or compounds and the production of metallic aluminium
substantially as hereinbefore described.
Secondly Treating the partially fused mass referred to in the last claim with
chloride of potassium and chloride of sodium and heating it to fusion so as to permit
of the particles of metallic aluminium to collect together substantially as hereinbefore
described.
Thirdly Making alloys of aluminium by treating the mass referred to in the first
claim in the manner described and adding it to copper or the other metal or metals
which it is desired to alloy with aluminium melted in an open furnace or in a crucible
or melting-pot or adding such metals to the mixture of aluminium compounds before
heating substantially as herein before described.
Lastly Manufacturing aluminium by first making in the manner described an
alloy of zinc and aluminium and distilling or driving off the zinc by heat so as to leave
free metallic aluminium substantially as hereinbefore described.
Dated the Seventh day of February 1889.
W. T. WHITEMAN,
Agent for the Applicants: