Improvements in the Production of Metals of the Earths and Alkaline Earths.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Production of Metals of the Earths and
Alkaline Earths.
1. ALEXANDER FELDMANN, of 17 Falkenstrasse at Linden near Hanover, kingdom
of Prussia, do hereby declare the nature of this invention to be as follows:-
My invention consists in the electrolytic production of metals of the earths (alumi-
nium, silicon, and beryllium, as also the rare metals cerium, lanthanum, didymium,
zirkonium, yttrium, erbium and thorium) and of the alkaline earths (barium,
strontium, calcium, magnesium) from haloid compounds thereof through the medium
of certain oxides, and from the oxides of the said metals through the medium of
certain haloïd salts, the radicals of the substances used as media being in a higher
degree electropositive than the metals to be obtained.
If the metal of the earth or alkaline earth is to be separated out from a haloïd
compound, which may be a simple salt of the said metal or a double salt thereof and
of an alkali-metal, an oxide is added being an earth, an alkaline earth, or an alkali
whose metallic base has the aforesaid property, the mixture is melted and exposed to
the electric current.
If on the other hand the metal is to be produced from its oxide, the latter is mixed
with a haloid-salt or salts of one or more earth,-alkaline earth, or alkali-metals
which is, or are all, more highly electro-positive than the metal of the oxide, and the
mixture is treated as in the first case.

page_text: COMPLETE SPECIFICATION.
Improvements in the Production of Metals of the Earths and
Alkaline Earths.
I, ALEXANDER FELDMANN, of 7 Falkenstrasse at Linden near Hanover, kingdom of
Prussia, Chemist, 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 :-
My invention consists in the electrolytic production of metals of the earths (alumi-
nium, silicon and beryllium), and of the alkaline earths (barium, strontium, calcium,
magnesium) from haloïd compounds thereof through the medium of certain oxides,
and from the oxides of the said metals through the medium of certain haloid salts, the
oxides and haloid salts used as media being such as have metals that are in a higher
degree electropositive than the metals to be obtained.
If the metal of the earth or alkaline earth is to be separated out from a haloid
compound, which may be a simple salt of the said metal or a double salt thereof and
of an alkali-metal, an oxide is added being an earth, an alkaline earth, or an alkali-
whose metallic base has the aforesaid property, the mixture is melted and exposed
to the electric current. In this manner, for instance, magnesium may be obtained
from the double chloride of magnesium and potassium by the employment of the
oxide of calcium or of sodium, while aluminium may be extracted from the double
chloride of aluminium and sodium by means of oxide of calcium.
If, on the other hand, the metal is to be produced from its oxide, the latter is mixed
with a haloid salt or salts of one or more earth,-alkaline earth, or alkali-metals
which is, or are all, more highly electro-positive than the metal of the oxide, and the
mixture is treated as in the first case. This process leads, for instance, to the pro-
duction of magnesium if magnesium-oxide is introduced into a bath of fluoride of
calcium and chloride of sodium, and to that of aluminium if aluminium-oxide is
added to a bath of fluoride and chloride of calcium.
In carrying out the process in practice I employ vessels or pots composed of
non-metallic materials being preferably composed of a basic substance free from
silicon and during the process I heat these vessels or pots externally to a suitable
temperature for maintaining the fluidity of the mass.
The liquefaction of the latter may be facilitated by the introduction of a suitable
flux. Each pot may be heated by a separate fire or one furnace may be arranged
to heat a series of pots. Both electrodes may be composed of carbon being mado
in the form of plates bars or other suitable shapes. When it is desired to obtain
pure metal the negative electrode is preferably composed of pure carbon or of a
metal on which the metal to be separated can be deposited without forming an alloy
with the metal of the electrode but when an alloy is to be produced the negative
electrode is made of the metal (such as copper for example) with which the metal
is to be separated is to be alloyed.

page_text: The positive electrode is preferably made of carbon but it may consist of a meta
(such as platinum for example) which is not liable to be affected by contact with the
contents of the vessel or when alloys are being made it may be composed of the
same metal (copper for example) as the negative electrode." The employment of
carbon electrodes is not essential this substance having no influence on the electro-
lytic action and being mentioned hero merely because carbon electrodes are the
most economical.
The strength of the current employed varies according to the nature of the
metal to be separated and the temperature of the materials or melt. Good results
are obtained with a current of from 4 to 8 volts and a suitable number of
Amperes.
The proportions of the ingredients composing the melt may vary considerably as
indicated by the following examples.
Chloride of Calcium 400; Fluor spar 100 and clay or-Alumina 100 or Chloride of
Calcium 300. Fluor spar 75 and Clay or Alumina 100 or-Chloride of Calcium 200,
Fluor spar 100 and Magnesia 50, or Chloride of Calcium 100, Cryolite 100 and
lime 40. I do not limit myself to these proportions which are merely given as
examples of combinations which have been found to yield satisfactory results in
practice.
There are no bye products produced in the melt.
Having now particularly described and ascertained the nature of this Invention
and in what manner the same is to be performed I declare that what I
claim is.
The process of producing the metals of the earths (aluminium, silicon and
beryllium) and alkaline earths (barium, strontium, calcium, magnesium) which
consists in adding to a haloid salt of the said metals or to a compound thereof with
a haloid alkali-salt an oxide of an earth,-earth-alkali,-or alkali-metal which is
more highly electropositive than the metal to be separated out, or in adding to an
oxide of the earth,-
,- or earth-alkali-metal a haloid compound of one or more earth-
alkaline earth,- -or alkali-metals which is, or are, all, more highly electropositive
than the metal to be obtained, in melting the mass and decomposing the same by
the electric current.
Dated the Ninth day of February 1889.
CARL PIEPER,
Agent for Applicant.