Improvements in Electrical Smelting.
Year: 1890

page_text: Date of Application, 9th Aug., 1890
Complete Specification Left, 8th May, 1891-Accepted, 4th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in Electrical Smelting.
1. EDUARD TAUSSIG, of Bahrenfeld, near Hamburg, in the German Empire,
Factory Manager, do hereby declare the nature of my invention to be as follows:-
This invention consists in a certain improvement or improvements in the electrical
smelting of metals. The improved process differs from that heretofore known in
that the production of the necessary heat for smelting is not produced by the electric
arc, but by a continuous current passing by conduction through the materials to be
smelted (whether mixed with flux or not) whereby the transformation of the
electrical energy into heat and the concentration of the latter on or about the
materials to be smelted are brought about by the resistance of the said materials.
To this end the material to be smelted in a state of sufficient tenuity is included in
the circuit between electrodes of large surface, and of suitable material preferably
of the same metal as that which is to be smelted out. The heat necessary for
smelting is thus produced by the resistance at the numerous points of contact in the
material. The reduction in the production of heat due to the increase in the cross
section of contact in the material as the smelting progresses is equalized or
substantially equalized by the increased temperature of the smelting material so
that the temperature is maintained at the requisite height during the whole process
of smelting.
Dated this 9th day of August 1890.
HERBERT & CO.,
Agents to the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electrical Smelting.
I EDUARD TAUSSIG of Bahrenfeld in the Empire of Germany, Factory Manager,
do hereby declare the nature of this invention and in what manner the same is to
be perforined, to be particularly described and ascertained in and by the following
statement :-
This invention consists in a certain improvement or improvements in the electrical
smelting of metals. The improved process differs from that heretofore known in
that the production of the necessary heat for sinelting is not produced by the electric
arc, but by a continuous current passing by conduction through the metals (whether
mixed with flux or not) to be smelted whereby the transformation of the electric
energy into heat and the concentration of the latter on or about the metals to be
smelted are brought about by the resistance of the said metals. The advantage of
this is, that the molten metal is not rendered impure through the chemical change
of charcoal or other substances during the smelting. To this end the metal to be
smelted in a state of sufficient tenuity is included in the circuit between electrodes
of large surface and of suitable material, preferably of the same metal as that
which is to be smelted out. The heat necessary for smelting is thus produced by
the resistance at the numerous points of contact in the metal. The reduction in
the production of heat due to the increase in the cross section of contact in the
metal as the smelting progresses is equalized or substantially equalized by the
increased temperature of the smelting metal, so that the temperature is maintained
at the requisite height during the whole process of smelting.
The temperature of the molten metal is maintained because after melting, the
resistance to conductivity of the melted product still remains much greater than
D621

page_text: that of the conductors, for the resistance to conductivity of the metal increases
proportionately to the absolute temperature. For instance for steel having a melting
point of from 1800 degrees to 1900 degrees Centigrade, the resistance at the melting
temperature is from six to seven times as great as at the ordinary temperature and
even then it is six times that of copper. At, the melting temperature it is
consequently about forty times more than that of the copper. If the total cross
section of the copper conductors, which usually consists of a number of thick cables,
amounts to one square metre then the open cross section or cross section of the
furnace and hence of the molten metal inay also be one square metre. The
disengagement of heat in the furnace will then be forty times as great as in
the conductors per unit of length. Thus if the conductors have an aggregate length
of four metres and the furnace an inner length of four metres the total heating of
the conductors will only amount to one-fortieth of the heat of the steel.
It will be seen from the above that the contact resistance of the pulverized metal
is only necessary for the commencement and early period of the smelting but when
the temperature is raised to the melting point, the temperature will itself supply
the required resistance to melt the metal.
In carrying out the process a furnace is employed as represented in the annexed
drawing where Fig. 1 is a vertical section and Fig. 2 a plan of the same; A is the
furnace; m the granulated metal to be melted; D and D are plate shaped electrodes
placed on opposite sides of the furnace, which electrodes reach to the bottom and
are connected with the positive and negative terminals by means of metallic
conductors of very small resistance, such as copper. When, now, currents of
suflicient strength pass from the one plate to the other, the smelting takes place in
consequence of the heat produced by the resistance to the passage of the current.
When the bottom of the furnace is provided with an exhaust opening e, the smelting
process may be made continuous by occasionally drawing off and recharging with
new metal in the upper part.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The process of reducing previously granulated metals to the fluid condition
between electrodes of large surfaces in a smelting furnace by means of an electric
current, but without the employment of an electric arc and other substances than
the metal to be smelted in such a way that, by the passing of the electric current
from one electrode to the other, in consequence of numerous contact resistances a
concentrated high temperature is produced in the metal which is smelted in an
intermittent or continuous manner substantially as described.
Dated this 8th day of May 1891.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.