US1197137A - Method of reducing metals. - Google Patents

Description

R. J. McNITT.

METHOD OF REDUCING METALS.

APPLICATION FILED JAN. 2. 1913.

Patented Sept. 5, 1916.

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WITNESSES W Lr I? 017W t1 ti ROBERT J. MGNITT, OF PERTH AIVIBOY, NEW JERSEY, ASSIGNOR TO THE ROESSLER, & HASSLACHER CHEMICAL (30., OF NEW YORK, Y., A CORPORATION OF NEW YORK.

Mn'rnon or REDUCING METALS.

mower.

Application filed January 2, 1913.

To all whom it may concern Be it known that 1, ROBERT J. MoNrr'r, a citizen of the United States of America, residing at Perth Amboy, Middlese-x county, New Jersey, have invented a certain new and useful Method of Reducing Metals, of which the following is aspecification.

My invention relates to a new and useful method of reducing metals from compounds containing the same and it refers particularly to the reduction of metals from their compounds by electrolyzing the same under pressure.

The reduction of metals by electrolysis has been long practised by many processes, but in all cases the electrolysis has been carried on under pressures substantially equal to the atmospheric pressure. Now I have found that by carrying on the electrolysis under greater pressures than atmospheric pressure, the reduction is more complete and results in more economical separation.

Furthermore, whereas it has been found impossible to continuously and. economically reduce many metals by electrolysis by the processes and apparatus heretofore proposed. l have found that by the practice of my invention this may be most satisfactorily accomplished.

I By way of illustrating my invention, I may cite as an example, the reduction of metallic sodium from molten sodium chlorid by electrolysis under pressure. Among those familiar with this art it is considered to be impossible to separate metallic sodium from molten sodium chlorid at temperatures in the neighborhood of the melting point of this compound which is in the vicinity of the boiling point of sodium, so that the high volatility of the sodium metal at the former temperature gives ,rise to various difiicillties. I find however that by carrying on electrolysis under a pressure of 900 mm. mercury, while maintaining the temperature of the electrolyte below its boiling point at atmospheric pressure, the boiling point of the liberated metal is raised approximately 100 C. and thelatter may be easily collected. i

I shall-explain my invention in connection with the accompanying drawing, which is a vertical longitudinal section showing in rather a diagrammatic way one form of elec trical apparatus suitable for the purpose.

A indicates an anode of graphite or other Specification of Letters Patent.

I Patented Sept. 5, 1916..

Serial No. 739,710.

suitable material which is electrically connected with conductors B extending through the external walls of the furnace. A cathode C, of any suitable material, is shown as connected on its lower side with a conductor D extending through the bottom of the furnace. The walls of the furnace are shown as formed of steel-plates E lined on the inside with a thin layer of asbestos F and the remaining spacebetween said walls and the rear sides of the electrodes and above the anodes is filled with a suitable material such as brickworlLG preferably fire clay brick. The working chamber of the furnace extends from the bottom X up to cover H.

Z indicates a bell of any suitable material, shown as somewhat larger in its lateral extension than cathode C.

K represents a diaphragm of perforated metal, extending downward from the lower rim of the bell Z and hanging between the anode and cathode surfaces.

The lower rim of bell Z is shown as terminating a short distance from the upper edge of the cathode C.

Z indicates a tube connected to the upper part of bell Z and passing through a cover H. Tube Z is connected by pipe L with pipe M, provided with a valve M. A pipe N is shown as branching off from tube Z and connecting to a vessel 0, provided with a Valve 0'. vessel 0 serving as a receiver.

A pipe P, provided with a valve P, conducts away the gases generated in the process and another pipe Q, of suitable diameter and provided with a suitable cover, serves for charging the metallic compound, as for instance sodium chlorid, into the furnace. A pressure gage R, carried by the cover H, serves for indicating the pressure exerted on the contents of the furnace.

lln carrying out my method of reducing metals from their compounds by electrolyzing the same under pressure I prefer to charge the apparatus, described above, with molten sodium chlorid until it approximately reaches somewhat below branchpipe N so that the lower .ends of both pipes M and Q are submerged somewhat in the liquid electrolyte. Immediately after charging in the molten sodium-chlorid I open valve M and admit some inert gas, such as producer gas, through pipes M and L in such quantities as to exert pressure on the electrolyte within the working chamber and I then pass the electric current through the furnace to start the electrolysis for the reduction of the sodium metal at the cathode C, Valve P is then opened just enough to throttle the escaping chlorin gas thus maintaining the pressure exerted on the electrolyte. It is obvious that the chlorin will pass freely through the electrolyte and out through pipe P and valve P, whereas the path of the sodium, after being separated at the cathode, is so directed that the sodium rises and is collected within bell Z. As the continuous electrolysis constantly increases the volume of the metallic sodium within the bell, owing to the difi'erence in the specific gravity of the respective liquids, the sodium rises in the bell and finally overflows through pipe N into receiver 0.

It is obvious many changes may be made in the process described above without departing from the spirit of my invention; one such change, for instance, consists in carrying on the electrolysis under the hydrostatic pressure due to a high column of fluid which may consist in part or whole of the molten electrolytic compounds, instead of creating the pressure by means of gases. Such change constitutes only one illustrative modification of the method described and comes within the scope of my invention, inasmuch as it does not bring about a change of material conditions in regard to the chemical or physical sides of the invention. It is further obvious that many other changes may be made, as for instance charging the metallic compound in a solid instead of in a molten state; modifying the form and construction of the bell Z as to allow the introduction of cathode C and its conductor D from the top instead of through the bottom or making other changes in the relative position of the electrodes without in the least interfering with the working of the process as described.

The application of gas for exerting pressure on the electrolyte makes it essential that the gas fulfil certain conditions; first of all any gas used as an auxiliary should be reasonably dry; it is desirable furthermore that it be inert as well to the chlorin gas as to the metal separated at the cathode.

I Wish also to state that the electric furnace may be built in either square or round shape and that the various material parts as for instance the electrodes, may most readily be adapted to fit eithershape. The apparatus described is one of the forms which is well suited for the reduction of metallic sodium from its compounds, preferably sodium chlorid, said reduction of metallic sodium being heredescribed simply as an example of my method of reducing metals.

The apparatus is'not claimed in connection with this application, as I reserve the same as the subject-matter of another application for patent to be hereafter filed.

What I claim and desire to secure by Letters Patent is: l. A method of reducing metallic compounds to their metals by electrolysis consisting in raising the boiling point of said metals by pressure on the molten electrolyte while maintaining the temperature of the electrolyte below its boiling point at atmospheric pressure.

2. A method of reducing metallic compounds to their metals by electrolysis consisting in raising the boiling point of said metals by pressure of a compressed gas on the molten electrolyte while maintaining the temperature of the electrolyte below its boil ing point at atmospheric pressure.

3. A method of reducing metallic compounds to their metals by electrolysis consisting in applying pressure to the metallic compounds forming the electrolyte, by means of compressed inert gas and then electrolyzing the metallic compounds while under pressure.

i. A method of reducing metallic compounds to their metals by electrolysis consisting in raising the boiling point of said metals by pressure of a gas generated by and compressed during the reduction process, on the molten electrolyte while maintaining the temperature of the electrolyte below its boiling point at atmospheric pressure.

5. A method of reducing metallic compounds to their metals by electrolysis con sisting in exerting pressure on the metallic compounds forming the electrolyte, by means of both a compressed inert gas admitted to the furnace and a gas generated by and compressed duringthe reduction process and then electrolyzing the metallic compounds while under pressure.

6. A method of reducing metallic compounds to their metals by electrolysis consisting in providing in an electrolytic chamber said metallic compounds in a fluid state, applying pressure to the metallic compounds by means of compressed gas, passing the electric current through the bath of metallic compounds, separating the products generated at the electrodes as desired and controlling the applied pressure by means of gases liberated by the process and gases admitted from without.

7. A method of reducing metallic sodium from its compounds by electrolysis consisting in raising the boiling point of the sodium by pressure on the molten electrolyte while maintaining the ten'iperature of the electrolyte below its boiling point at atmospheric pressure.

8. A method of reducing metallic sodium from its compounds by electrolysis consisting in raising the boiling point of the someme? dium by pressure of a compressed gas on the molten electrolyte while maintaining the temperature of the electrolyte below its boiling point at atmospheric pressure.

9. A method of reducing metallic sodium from its compounds by electrolysis consist ing in applying pressure to the sodium compound forming the electrolyte, by means of a compressed inert gas and electrolyzing the sodium compound While under pressure.

10. A method of reducing metallic sodium from its compounds by electrolysis consisting in raising the boiling point of the sodium by pressure of a gas generated by and compressed during the reduction process, on the molten electrolyte while maintaining the temperature of the electrolyte below its boiling point at atmospheric pressure.

11. A method of reducing metallic sodium from its compounds by electrolysis consisting in exerting pressure on the sodium compound forming the electrolyte, by means of both a compressed, inert gas and a gas generated by and compressed during the reduction, and electrolyzing the sodium compound while under pressure.

12. A method of reducing metallic so dium from its compounds by electrolysis consisting in providing in an electrolytic chamber said sodium compounds in a fluid state, applying pressure to the sodium compounds by means of compressed gas, passing the electric current through the bath of the sodium compounds, separating the products generated at the electrodes as desired and controlling the applied pressure by means of gases liberated by the process and gases admitted from without.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

v v ROBERT J. MGNITT. Witnesses: I

HERBERT PHILIPP, OTTO K. ZWIN-GENBERGER.

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