US2217665A - Process and means for recovering vanadium and uranium from ores - Google Patents

Description

Oct. l5, 1940. H. D. BROWN y 2,217,665

PRCESS AND MEANS FOR RECOVERING VANADIUY AND URANIUM FROM @RES I Filed Aug. 22, 193s van, m

. l* ATTORNEY.

`Patented Oct. 15, 1940 UN'ITTF-DEY STATES' -Pmjclrss AND MEANS Fon. `lalicovuiuncr VANADIUM ANDURANIUM FROM onus.V

Harry D. Brown, Palisade, 001g. v Application August 22, 1938, Serial No. 226,086r 1 claim; f (c1. as is) AThis invention relates to a process and tothe means for carrying out the process for k.treating carnotite and othervanadium-uranium lores for therecovery of .thefvanadium and/or uranium i values therefrom.- I .f i

The principal objectof `the inventionis to provide a continuous process by means of which the values maybe extracted ata minimum of cost. Another object of the inventionis to provide a highlyl ecient treating mechanism which `will continuously and successivelyreduce or roast the ore, then immediately oxidize the hot roast in the presence of heat and moisture; thence collect the oxidized oreand `deliver it to a continuous cooling ll apparatus. l y

Other advantages result from the improved process and the apparatus employed in carrying out the process. These will become more appar.; ent from the following description. In the following detailed description of the invention reference is had to the accompanying drawing which formsa part-hereof. Like numerals refer to like parts in all views of the drawing and throughout the description. Inthe drawing: Y

Fig. 1 is a longitudinal section through the improved treatment apparatus which is employed in carrying out the improved process.

`vFig. 2 `is` a vertical cross section-therethrough taken on the line 2-2, Fig. 1. f 1 l Fig. -3 is a detail section taken on the line 3'-3, Fig.1. 'f

The apparatus consists-of'a masonry furnace structure I2 lined with fire brick or` other -re resisting material. Are box or oxidizing cham#-v ber I3, a precipitating chamber I`4,' and a con# vection chamber I5 are containedwithin the furnace structure.V The oxidizing chamber is sepav rated from the --precipitating chamber `I4kby im meansof ahollow back wall 311 inwhich there is a. relatively lo'w iire arch IIS. 'A-stack I'I con- Veys the combustion gases from the far end ofy thecnvection chamber I5.

A rotating ore drum I0 extends completely throughout the length of the convection chamber I5 and is supported on the exterior of the furnace upon suitable bearing rollers II. The drum I0 is provided at one extremity with a feed hopper I8, through a hollow trunnion I9, and at its other extremity carries an enclosed discharge chute 20. The drum is rotated from any desired source of power through the medium of a suitable drive sprocket 2| and is provided throughout its interior with a conveyor screw 22 and on its exterior communicating with the drum with inclined conveyor paddles l23, which extendY in a close .proximity tothe Walls ofthe chamber A settlings passage-24 opensfrom the bottom of the convection chamber I5 adjacent the pre- 5- cipitating chamber I4.- This .passage extends downwardly in the back wall 3l and separates to each side of the arch Ivinto the side walls of the` furnace openingfto the latter Abeneath the arch and `above a pair Vof screw-conveyors 25 10 which extend-throughout the length ofthe bottom of the furnace structure,-

The conveyors-25 are of the usual'h'ollow shaft type and arev water-cooledby passing' water-from aL water supply 26`through the hollow conveyor 16 shaft 28. I rThe Iconveyors aredriven'from any suitable source ofl powerthrough drive sprockets 29 and rotate in a direction to convey material toaninclined ore passage 30 leadingto a revolving cooling drum 3|. f I 20 A gas or oil burner 32 is positioned at one extremity of the oxidizing chamber? I Beso as to blow a' iiame therein. This lburner lmay be lof any' suitable type to which fuelis furnished through a fuel pipe 33 and air is furnished through -an 25 airpipe34. 'Y v,

Steam jets 35 are also' directed into the oxidizing chamber immediately below the chute 2U.r A steam plate 36 is'positioned below the chute 20, and directly under the steam jets'35, toreceive 30 thel roasted material from the roaster |015 f- Operation v 5.

Before being fed to the roastenthe ore is in# termixed with a suitable reagent' in predetermined 35 proportions. The particular` reagent employed depends upon whethervthe'recovery-isto be'vanadium alone or both vanadiumvand uranium. vThe choice, of course, depends upon the particular ore being worked, as towhether there is sufficient ura. nium therein to warrant extraction. If both vainadium and uranium are tofbe extracted, sodium chlorideI and/or: vsodium carbonate are-used. Should vanadium be the only product to be extracted, the sodium chloride alone. is preferred 45 as the reagent. y

The ore containing the proper percentage of the chosen reagent is fed into the hopper I8 from whence it flows into the decrepitating drum or chloridizing roaster I0 through which it is slowly 50 conveyed by means of the screw 22. 'Ihe heat in the convection chamber I5 and the speedof travel of the ore are regulated to elect a substantially complete decrepitation or pulverization of the ore before it is delivered to the dischargev chute '55 20. The drum is sealed to provide a non-oxidizing atmosphere.

During its travel through the roaster, the ore is decrepitated by the dehydrating action of the heat and the impacts imparted by the cascading rotating action so that preliminary grinding costs are greatly reduced. The ore discharges into the receiving chute 20 at a temperature of approximately rl50"`IE. From the chute, it falls upon the steam table 36 into the steam blasts from the jets 35, which instantly blow the hot ore into the oxidizing flame in highly dispersed condition intermixed with the water particles in the steam. The name within theoxidizing chamber produces a temperature of approximately 2000*" F. which completelyoxdizes and calcines the ore and decomposes the steam to furnish' additional oxidizing oxygen.

The combustion gases, with the suspended ore particles are deflected downward by the back 'wall 3,1 through the restricted opening below the arch I6. l,This throws a portion of the suspended oxidized ore or dust downwardly onto the conveyors 25. The gases then enter the precipitatingchamber I4 where they expand and lose velocity so as to, release the remaining suspended dust to the conveyors 25. The gases then rise to and flow through the convection chamber l5 to the stack l1. Any remaining ore dustrin the gases will be droppedin the convection chamber and will be conveyed back by means of Scrapers 23 to the settlings passage 24 from whence it will fall downwardly around the arch I6 to the conveyors 25.

The, ore dust is collected and carried by the conveyors to the ore pass 30 from whence it is de,- livered to the cooler 3l. The temperature of the calcined product flowing through, the ore pass 3l) is approximately 1520 F.

,-After being cooled, the vanadium and uranium is dissolved from the calcined ore in the basic leach. Y,

The reaction in the chamber Il is essentially a chloridizing roast. The ore decrepitates under this condition of heat in the non-oxidizing atmosphere of the drum thereby assisting reagent contact with the mineral or minerals contained in the minute interstices of the sand grains. Themineral or mineralsv having the power of combination are chloridized, intimately lmixed with the chloridizing reagent and `are rendered nascent for immediate oxidation. rI he speed of the chemical reaction is greatly inuenced by temperature, by concentration of the reacting substances and by the intimacy and amount oi contact surface provided in the chloridizing roast, by the cascading action and, in the oxidizing chamber, by the dispersion of the ore. The steam used to blow the ore into the oxidizing chamber becomes dissociated and forms an eilicient oxidizing agent. 'I'he reaction in the oxidizing chamber is that chlorine is liberated and passes off with the gases of combustion, while the sodium combines with the vanadium to form a water soluble sodium vanadate.

In the event of using sodium carbonate with the i sodium chloride as reagents, a certain amount of carbonates are formed in the reducing chamber which persist throughout the roast. The CO2 combines with the uranium.

By decrepitating the ore during chloridization, the time required for vcalcining is greatly reduced, the reagent contact with the vanadium and uranium is more efficient, and the mechanical features of the roaster areA greatlysimplied, therefore both the initial cost and theoperatin'g costs are low.

' The ore of the sodium chloride reagent roast is leaclled with water; The calcined ore renders the leaching solution basic. The soluble sodium vanadate passes into solution and is then ready for precipitation. The combined reagents, sodium chloride and sodium carbonate, when used to Arecover both uranium and vanadium from the ore vmust be treated differently in the leaching ,of same.` As above stated, a certainvamount of fthe CO2 combines with the uranium rbut insufficient to prevent precipitation that must be controlled. Therefore, just sufficient sodium carbonate is added to the leaching solution to keep the sodium uranyl carbonate in solution, the same being soluble in anexcess of `sodium carbonate. The vanadium is also soluble in this solution and the two products may be selectively precipitated. By expelling the CO2 ofthe solution, uranium will precipitate as sodium uranate. Theprecipitation of the vanadium follows.

'Ihe machine is particularly valuable in providing an e'icient treating mechanismof low initial cost and low operating cost. l

While this invention has been described as particularly applicable to carnotite and other vanadium-uranium bearing ores for `the recovery of vanadium and/or uranium values therefrom, it is not to be construed as limited to these particular ores. Y,

While a specic-form of the improvement has been described and illustrated herein,it is desired to be understoodthat the same may be varied, within the scope of the appended claim, Without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured byLetters Patent is:

A process for treating vanadium ores to-form soluble vanadates comprising: the steps of forming a mixture ofthe ore and a salt from theclass consisting of sodium chloride and sodium carbonate, subjecting the mixture inaclosed drum to a heating and agitation in a non-oxidizingatmosphere, discharging the mixture `from the c' drum into an oxidation chamber, dispersing the mixture therein by a steam `jet subjecting the mixture while in a dispersed vcondition to -an ,oxidizing roast to convert the vanadium values 7thereingto vanadates, collecting v the Yroasted product and leachingit to recover the vanadium values.

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