US1493126A - Process of making elemental sodium from borax - Google Patents

Description

Patented May 6, 1924.

UNITED STA'TESPATENTOFFICE. 3

SAMUEL PEACOCK, OF WHEELING, WEST VIRGINIA, ASSIGNOR TO WILLIS G. WALZDO OF WASHINGTON, DISTRICT OF COLUMBIA. a

. PROCESS OF MAKING ELEMENTAL SODIUM FROM BORAX.

No Drawing.

T all whom it my concern Be it known that I, SAMUEL PEACOCK, a citizen of the United States, residin .at Wheeling, in the county of Ohio and tate of West Virginia, have invented certain new ,and useful Improvements in Processes of Making Elemental Sodium from Borax; and I do hereby declare the following to be a full, clear, and exact description of the in- 10 vention, such as will enable others skilled-in the art to which it appertains to make and use the same.

This invention relates to a process of making elemental sodium from borax, and

15. has for its object to provide a procedure which will be more eflicient in practice and less costly to carry out than those heretofore proposed.

With these and other objects in view, the

invention consists in the novel steps and combinations of steps constituting the process, all as will be more fully hereinafter disclosed and particularly pointed out in the claims.

In carrying out this invention I take sodium tetra-borate Na B.,O,.1OH commonly known as borax, finely divide the same and intimately niix it with finely divided coke, or charcoal, or other suitable carbonaceous material in proportions preferably in excess of thoserequired by theory.

The charge thus produced is placed in a retort furnace or other suitable furnacing apparatus wherein the heat treatment will take place in an atmosphere which can be positively controlled and from which the air may be excluded. The charge is now raised to a preliminary temperature of about 600 C. in order to drive off the water of crystallization, and to expel substantially all the occluded gases present, and for this purpose any suitable source of heat may be employed. The temperature of the heated charge under an exclusion of air, is next raised to about 1000 (3., when the breaking up of the anhydrous borax and the distillation of the elemental sodium will begin in accordance with the following equation:

It "is preferred to maintain the partial pressure of the evolved gases somewhat in excess of one atmosphere in the furnace chamber in order to facilitate the vaporization and separation of the metallic sodium Application filed December 8, 1921. Serial No 529,993.

from other charge constituents'as well as its escape to suitable condensers as rapidly as it is evolved.

Of course, the higher the temperature maintained in the furnace, the more rapidfio will be the evolution of the elementalsodium, but if the temperature is raised much above 1200 C..or 1300 C. it is found that an appreciable quantity of unconverted boron oxide, B 0 distills over, unless an excessive pressure is maintained in the furnace. That is to say, as no large scale furnace operation is confined to a single reaction, a considerable proportion of boron oxide is liable to be formed in some parts of the furnace in accordance with the following equation:

and this said boron oxide not only contaminates the sodium, but it tends to clog the passages of the apparatus. Therefore, it is preferred for economic reasonsnot to em-' ploy a furnace temperature higher than, say 1150 C. or 1200 C. when evolving the sodium content, of the borax, under normal conditions.

If only enough carbon has been employed to satisfy the last mentioned equation, after the evolution of the sodium has ceased, the

urnace residue consisting of boron, boron oxide, and various impurities may be cooled, and said boron recovered in an suitable manner, or said residue may be raised to say 1300 C. or 1400? (3. and said oxide recovered by sublimation.

This latter method'is to be. referred if the recovered boron oxide is to e employed as a raw material in the production of boron nitride, in accordance with the disclosure of my Patent No. 1,464,292, dated Aug. 7, 1923, and entitled Process of producing boron nitride, for it is found that such a distillation of the oxide from its associated impurities produces said oxide in a high state of purit It will be observed, however, that the sodium acts cyclically in reducing all the boron oxide with whlch it comes into intimate contact. That is, sodium and boron oxides are probably formed as intermediate products, the sodium oxide being reduced by the carbon, and the resulting sodium reacting on the boron oxide to reform sodium oxide. The process thus continues until all fairly uniform temperature throughout the charge, very little boron oxide will be left in the furnace. On the other hand, ;-by omitting these precautions boron oxide" can be readily produced in accordance with the second equation above mentioned. As soon as all the available combined oxygen has been thus used up by the sodium and converted into carbon monoxide, the elemental sodium Wlli sublime and be rapidly recovered in the condensers.-

As elemental boron does not readily alloy with sodium, and only sublimes at about 1600 C. its recpvery is easily effected, and it constitutes a valuable by-product, which lessens the cost of the sodium. That is, after separating out'the sodium and any boron oxidethat may have been produced, the temperature of the residue is again raised to 1600 C. or higher, whereupon the elemental boron is driven off, and recovered in condensers.

It is obvious that those skilled in the'art may vary the details of the process without departing from the spirit of the invention, and therefore I do not wish to be limited to the foregoing disclosure except as may be required by the claims.

lVhat is claimed is:

1. The process of producing elemental sodium which consists in reacting on anhymemes drous sodium tetraborate with carbon in an atmosphere substantially devoid of free oxyto a temperature sufficient to render the said borate anhydrous; raising the temperature to a point. at which elemental sodium is produced; and recovering said sodium, substantially as described.

3. The process. of producing elemental sodium from an anhydrous sodium borate which consists in mixing said borate with carbon in excess: heating the mixture in an atmosphere devoid of free oxygen to a reacting temperature to drive off the sodium in its elemental form; and recovering said sodium, substantially as described.

4. The process of producing elemental sodium and elemental boron from anhydrous sodium tetraborate which consists in adding sufficient carbon to said borate to produce said sodium and boron; raising the temperature in an atmosphere devoid of free oxygen to a reacting point; separating out the free sodium thus produced; and recovering the elemental boron left in the reacting chamber, substantially as described.

In testimony whereof-I aflix mysignature.

SAMUEL PEACOCK.