US2142031A - Process of aluminothermic smelting - Google Patents

Description

Patented Dec. 27, 1938 UNITED STATES PATENT OFFICE.

rnocnss or ALUmNo'rnEaMio SMELTING Otto H. Lorange, Columbiana, Ohio, assignor to United States Vanadium Corporation, a corporation oi! Delaware No Drawing. Application October 22, 1937,

Serial No. 170,345

3 Claims.

charge consisting of oxides of the metals and alloys to be produced, aluminum, and a flux, is ignited in a refractory-lined pot. A vigorous exothermic reaction takes place between aluminum and the oxydic compounds, reducing the latter, and the molten reduced metals sink to the bottom of the pot beneath a slag layer.

It is an object of this invention to improve and cheapen the aluminothermic smelting process, and another object is to increase the percentage recovery of metal. These and other objects which will be apparent irom the following disclosure are accomplished by my invention which comprises the replacement of a part of the aluminum in an aluminothermic mixture with carbon or carbonaceous material.

While the invention is applicable to aluminothermic smelting processes generally, it is particularly useful in'the manufacture of ferrovanadium.

In the production of ferrovanadium as previously carried out in aluminothermic smelting processes, a charge comprising an oxydicjpmpound of vanadium, such as vanadic'acid, an

oxydic compound of iron, such as roll scale or' mill scale, together with steel scrap, aluminum,

and a fluxing agent, usually fluorspar, is fed into a heated pot and ignited by a priming mixture. The vanadium and iron oxides are reduced in the resulting reaction, and molten ferrovanadium is obtained in the bottom of the pot.

In accordance with the present invention, a minor but substantial proportion of the aluminum in the charge is replaced by carbon, thereby efiecting an improved recovery of vanadium and a saving in aluminum. The presence of carbon in the charge causes the liberation ofcarbon monoxide gas, resulting in a continuous, gentle boiling within the reacting mass. The boiling action speeds up the reaction and hence shortens the smelting period. A higher temperature is apparently attained-with the use of carbon in the mixture, and the boiling action seems to cause I metal particles, suspended in the slag as a metal mist, to coalesce and join with the metal regulus.

Suspended metal particles are recovered which otherwise would remain suspended in the slag.

A specific example of results obtained by the 'use of the method of the invention, compared with those secured by the conventional method of aluminothermic smelting, serves to illustrate the advantages of the invention. Two heats, A and B, were made. Heat A was made by the method of the invention, and heat 13 was made by the conventional method. Charges for each heat were made as follows:

Charge Heat A Heat B I Pounds Pounds Crude vanadic acid 600 600 Mill scale 293 293 Aluminum shot 377. 5 382. 5 Steel scrap. 220 203 Fluorspan. 30 '30 Powdered coke 8 Total charge l, 528. 5 l, 508. 5

The crude vanadic acid contained 86.5% V205. The charges were fed into priming batches in refractory-lined pots. In each heat the priming batch contained 40 pounds of crude vanadic acid, 40 pounds of mill scale and 33 pounds of aluminum. A small quantity of a mixture of aluminum with barium peroxide was used to ignite the priming batches, and the smelting mixtures were then fed at an even rate into the pots. In each heat the reaction was complete in about four minutes, heat A finishing slightly faster than heat B. The slag of heat A boiled continu- -ously throughout the aluminothermic reaction a nd-ior several minutes thereafter, whereas there was little or no boiling action in the slag of heat B; After cooling in the pots, the metal reguli were easily separated from the overlying slag layer. The metal produced in each heat was weighed and analyzed with the following results:

Beat A Heat B Pounds alloy obtained 766 758 Percent vanadium 36. 45 36. Percent carbon 0.25 0.06

In heat A, which was made according to the invention, the recovery of vanadium was 91.2% whereas .in heat B, made by the old method, vanadium recovery was 90.2%.

The invention may be applied to aluminothermic smelting processes generally, as pointed out above, the amount of carbon which may be used depending on smelting conditions and the amount of carbon desired or permissible in the alloy being manufactured. If too large an addition of carbon is made, it may cause wildness of the reaction and may lead to loss of metal due to excessive spattering or boiling of the charge. The most desirable quantity of carbon to be employed in any application of the invention is preferably determined empirically, and is that amount which will cause a steady but not violent boiling during the aluminothermic reaction and preferably for a short time after the reaction is complete. Preferably, carbon is used to replace aluminum in approximately stoichiometric proportion.

I claim:

1. Method of producing metals and alloys by 'aluminothermic reduction of metal oxides which comprises replacing a minor but substantial proportion of the aluminum in the smelting charge with carbonaceous material suflicient to produce a steady boiling eflect in the said smelting charge throughout the aluminothermic reduction.

2. Method of producing ferro-alloys by alumino-thermic reduction of metal oxides which comprises replacing a minor but substantial proportion of the aluminum in the smelting charge with carbonaceous material in approximately stoichiometric proportion, the amount of carbon being sufllcient to cause a steady boiling effect in said smelting charge throughout the alumincthermic reduction.

3. Method of producing ferrovanadium by alumino thermic reaction which comprises incorporating, in approximately stoichiometric proportions, aluminum and carbonaceous material with oxydic compounds of vanadium and iron, adding metallic iron and slag-forming material, to form a smelting charge, the amount of carbon being sufiicient to cause a steady boiling efiect throughout the reaction and being a minor but substantial portion of the total of the aluminum and the carbonaceous material.

O'I'IO H. LORANGE.

CERTIFICATE F CORRECTION.

Patent No. .2,-1i 2,0 1

December 27, 19581.

o'rro H. 'LORANGE.

It is hereby certified that errorv appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 5, strike out the article "a": and second column, line. [1,5, in the table, under the heading "Heat A", forthe nur'neral""766" read 776;and that the said Letters Patent should be read with this correction therein that the same may conform to the. record of the case in the Patent Office.

Signed and sealed thisTth day of February, A.D. 1-959;

(Seal) Henry Van Arsdaler Acting Commissioner of Patents.. @l,