US1334179A - Albert w - Google Patents

Description

nnrrnn srx'rns PATENT onuion ALBERT W. SMITH AND winmem a. veneer, or CLEVELAND, OHIO, essionons To run DOW CHEMICAL COMPANS T, or- MIDLAND, MICHIGAN, A oonronn'rronr or MICHIGAN.

METHOD OF MAKING METALLIC SODIUM.

1,334,179. No Drawing.

To all whom it may concern:

Be it known that we, ALBERT d rlMrrr-r and WILLIAM R. Vnnznx, citizens of the United titates, and residents of Cleveland, county of Guyahoga, and State of Qhio, have jointly invented a new and useful 11nproveinent in Methods of Making Metallic Sodium, of which the following is a specification, the principle of the invention being herein. explained and the best mode in which we have contemplated applying that principle, so as to distinguish it from other in-' ventions.

The method principally used in the electrolytic manufacture of metallic sodium, 0., the sic-called Castner process, uses, as is well known, caustic soda (NaGH) as the material to be electrolyzed. A number of 0bjections, however, are involved in the electrolysis of such material, one being the fact that only one-half of the electric. current used is employed in producing sodium, the other half producing hydrogen by the electrolysis of the hydroxyl resulting from the first step. Furthermore, the hydrogen and oxygen that are produced form an explosive mixture, with the result that the cells, when in operation, are continually subject to more or less dangerous explosions, which at least serve to scatter fine particles of caustic in the atmosphere, if no more serious damage results; while the metallic sodium is soluble in fused sodium hydroxid, except for a relatively limited temperature range, so that it is necessary to confine the temperature within the cell to such prescribed limits. A

By reason of the aforementioned difliculties, and for the further reason that some cheaper material than caustic would of course be desirable,a number of other compounds of sodium have heretofore been tried, but none successfully, so far as we are advised. Common salt (NaCl), which would probably afford the cheapest source, unfortunately has so high a melting point thatthe sodium volatilizes and burns as it is formed, and the same is true of all the other available compounds or salts of sodium when used alone. It has also been attempted to work with mixtures of different salts. For example, caustic soda has been added to sodium carbonate (Na CO which latter alone fuses at too high a temperature, in an endeavor to obtain a lower fusing Specification of LettersiPatent. i Patented 313- 12 16, 15329,

Application filed October 12, 1918. Serial No. 257,835;

mixture; the result, however, is unsatisfactory because the caustic soda electrolyzes preferentially, and no advantageis accord ingly gained. v 1

Theobject of the present invention is to provide a suitable mixture of sodium compounds or salts for use in this electrolytic process, whereby metallic sodium may be produced at a much lower cost, not only by reason of the cheapening of the source-material, but also by requiring less current and otherwise simplifying and rendering less dangerous the operation itself. To the ac complishment of the foregoing and related ends, the invention, then, consists of the steps hereinafter fully described and particularly pointed out in the claims.

The following description sets forth in detail one approved mode of carrying out the invention, such disclosed mode, however, constituting but one of the various ways in which the principle of the invention may be used.

We have discovered that sodium compounds, and specifically sodium carbonate, uponbeing added to sodium salts other than caustic soda, in proper proportions, will give a mixture capable of fusion at a low enough temperature to avoid the vaporization and burning of the metallic sodium. At the same time, by a proper selection of these other sodium compounds, the carbonate or selected compound will electrolyze preferentially, which means that it isdissociated into its constituent elements at a lower voltage than the admixed compounds.

As an example of a mixture of the sort enerally referred to above, which has been ound entirely satisfactory in actual practice, we take a mixture of sodium chlorid with sodium carbonate, containing approximately two parts of the latter and one part of the former, for example, 35.6 parts of sodium chlorid and 64.4 parts of sodium carbonate by weigl'it. This mixture is found to have a melting point of approximately 600 0., and, upon being electrolyzed, produces metallic sodium of equal quality than that produced by the present commercial process. It will be obvious that by employing this mixture we obviate entirely the use of caustic soda even as a component of the mixture, and thus not only eliminate What is a difficult material to handle, but also utilize the full effect of the electric current in producing the desired product, 6., metallic sodium, instead of only fifty per cent. of such current.

Any suitable electrolytic cell may be employed in connection with the foregoing, a regular Castner caustic soda cell having been found entirely satisfactory in actual practice. With a mixture such as described above, it has been found possible. to work with a potential of six volts between the terminals of. the electric machine, indicating that. only a few volts are required to effect dissociation.

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the method herein disclosed, provided the step or steps stated by any of the fol lowing claims or the equivalent of such stated step or steps be employed 1 We therefore particularly point out and distinctly claim as our invention 1. The method of making metallic sodium, which consists in electrolyzing sodium carbonate in a fused mixture of such salt and sodium chlorid, the ingredients being learn /9 so proportioned that such mixture has a lower melting point than either of lts constituents.

2. The method of making metallic sodium, which consists in electrolyzing sodium carbonate in a fused mixture of such salt and sodium chlorid, the ingredients being so proportioned that such mixture has amelting point of approximately 6.00 G.

3. The method of making metallic sodium, which consists in electrolyzing. sodiumcarbonate in a fusedmi-xture of approximately two parts of such salt and one. part of sodium chlorid, such mixture having a lower melting point than either of its constituents.

4-. The method of making metallic sodium, which consists in electrolyzing sodiumcarbonate in a'fu-sed' mixture of 6%.4 parts of such salt and 35.6 parts of sodium chlorid, such mixture having a melting point of approximately 600 C.

Signed by us this 3rd day of October,

ALBERT W. SMITH. WILLIAM R. VEAZEY.