US1451333A - Art of making electrolytic iron - Google Patents

Description

f F. A. EUST|S`ET AL ART 'OF MKING ELECTROLYTIC IRON Orlgnal Filed Dec. l7

l /mes fone status entre Parser estres,

FREDERIC A. EUSTIS, OF MILTON, CABLE R. HAYWAED, QF QUINCY, AND HENRY M. SCHLEICHER AND DONALD BELCHER, OF BOSTGN,I*IASSVACHUSETTS, ASSIGNORS, BY DIRECT AND MESNE ASSIGNMENTS, OF ONE-HALF TO SAID EUSTS AND ONE-HALF T0 CHARLES PAGE PERIN, OF NEW YORK, N. Y.

ART 0F MAKING ELECTROJYTIC IRON.

Original application filed December 1, 1920, Serial No. 427,541. Divided and this'application ed July Serial No. 482,928.

lpreparation of the ferrous solutions suitable for the electrolytic deposit of' iron.

The present application is a division o'f an application ,filed by us December 1, 1920,

Serial No. 427,541, now Letters Patent of the United States No. 1,412,174, dated April 1 1-, 1922, ,and is addressed particularly to that modification of the invention .described in our ,said former application employing' an electric current for reducing the ferrie solution in the liquor discharged from the anode compartment of the electrolytic cell in which the i'ron is deposited. .i

The ferrous solution from'which iron is deposited by electrolysis may be a solution of ferrous chloride in Water, a ferrous sulphate solution, or indeed a solutionvcontain-v ing any` salts of iron that` will in solution dissociate to deposit iron under the action ,of electrolysis, that will form the two series of salts, ferrie and ferrous, and that will attack the ore or other raw material constitilting the source of iron. By way of illustration therefore, and not of limitation, we will describe the processes usingr 'a ferrous chloride solution.

The ferrous 'solution when made by the method hereinafter described will contain at least some acid or ferricsalts, sueltas ferrie chloride, although it may be only traces, and must be thoroughly neutralizedy before it is suitable for the production of electrolyt'ic iron, because the presence of acid or ferrie salts causes'a 'poor iron deposit and results in low current eiiiciency. To this end the solution is mixed with pulverized limestone in 'a suitable tank. Limestone furnishes calcium carbonate (CaCO3) which is the most suitable agent for neutralization, as 1t has the capacity of readily precipitating Iirst ferrie salts before precipitating the ferrous salts. iVehave found that for the best results it is advisable to use'l enough neutralizing agent to precipitate a small amount offerrous iron. lThis insures complete neutralization of the liquor, the` neutrality ,of the solution in the cathode compartment of the electrolytic cell beingJ an indispensable con# dition for the most efficient electrolysis of iron..

The solution is then filtered if necessary heated nearly to the boiling point, and passed hot into the cathode compartment of a diaphragm electrolytic celi. Under proper conditions vmetallic iron is deposited on the cathode. The liquor passes through the dia.-

ph'ragm into the anode compartment and is thence returned to the process to be used in making more ferroussolution as hereinafter l described.

The accompanying drawing illustrates dia-Y grammatically apparatus for performing the y process.

A special electrolysis celi is used for depositing the iron, ofthe kind fully described in our said former patent to which reference is made for a more detailed description of its constructicnand mode of operation.

The` hot anode liquor containing ferrie chloride and ferrous chloride {or ferrie andA ferrous sulphates. if the loriginal solution was a sulphate instead of a chloride) is discharged from the vmain electrolysis cell A in which the iron is deposited, into a second electrolytic cell `Gr i'vhich may be termed an electrolytic reducing tank. The application of electric energy to the ferrie solution in the electrolytic reducing tank G, Wiil reduce the solution from the ferrie to ferrous state. This 'reduction of the ferrie salts formed in electrolysis ceil A furnishes acid needed for dissolving the ore. The ferrous soiution resulting from this electrolytic reducing step constitutes a leach liquor by which the iron 'may be dissolved from the cre. The reduced leach` liquor is then. put on the ore in a s0111- tion tank B where it dissolves iron from the ore and is` then filtered at C. Thence the major part of the solution is pumped back to thereducing tank, G, While the smaller part of the solution which vmay still be` slightly acid will be ladvanced tofthe limel stone tank D in which it Will vbe neutralized. The solution from the limestone tank Dis then delivered hot, Vpreferably at a tempera-` ture in the `region of the boiling point, tothe electrolysis cell A for. the deposit of iron, andthe cycle repeated.

The part of the solution sentv to the limestone tank D may optionally be passed through a tank F containing scrap iron for the'purpose of further enriching the solution in iron and at the same time using up `part of the acid coming from the solution tank B before it, enters the limestone neutralizing 4tank' D. i y l It is desirable to' rovide agitation of some sort in thefsolution tank B. v l Thelreason for returning the greater part of the liquor from the ore solution tank to the reducing cell is that the electofthe action .of the leach liquor' on'most oxidized ores is to take iron into solution in ferrie state; therefore, the solution coming from the ore solution tank will contain ferric salts and mu'st.again be reduced.V

If alltleliquor were sentdirect tothe limestone neutralizing tank it would be necessary to use large amounts of limestone for neutralization because.. ofv the large amount of ferrie chloride present in ythe solution dissolved from the ore. This isnot.

only costl in limestone but may use` up too much aci in the neutralization step. There- .ore', a part of the solution issent from the ore solution tank back to the reducing cell Where the ferrie chloride dissolved from the l ore is reduced, and the solution so reduced upon again passing over the'cre picks up more ferrie iron but only one third as much as was present immediately before .it was reduced. Thus by repeatedly cycling part ofthe solution through. the reducino' tower andover the ore the ferrie iron in Athat part of the vsolution advanced to the limestone tank4 may be diminished toany point desired.

Since no acid is added for reductiongby the present method, but only electricalwenergy,"

there is no source of nevvl acid in the cyclic process itself and the acid must therefore be carefully conserved. This can be done by turning a large portion of the'solution from the ore solution tank back to the reducing cell and advancing only a small portion to the limestone tank for I ieutralizngf.l Even with this mode vthere is some .ofl acid which can economically be restor by blow- SO2 gas into the liquor in the reducing or at some other convenient point. When the' reduction of the anode liquor is performed by an electrolytic reducing cell,

vtank B. y v l s For a further division of the aforesaid ap? solvent. Many oxide ores occur in nature in fine condition and such will require only a final pulverizing treatments The mixture in the solution tank should be maintained at a high temperature, vas the hotter the mixture the more effective is the action. Good results maybe obtained at a. temperature of C. and above. It is also desirable to'stir or agitate the mixture in order'to insure constant contact of active solvent 'with thtJ ore; or percolation may be used. A counter-currentmethod of leaching is advised, f

.by which fresh ore is treated yvithlthe Weakest solution and the residue of the ore is `treated with fresh solution.

The process above described is particu-v larly adapted to thetreatment Iof oxidized ores of iron, such as limonite, liematite or magnetite, as the source'of iron, since the anode liquor resulting from the use 'of oxidized ores contains bothl ferrie and ferrous vchloride or sulphate and should be reduced to a ferrous state in order to make an effective solvent for the ore. It might also be used `for the treatment of' sulphide ore if the sulphideore isv of-suchcliaracter that the reduction of the solution Will not readily take place in the solution'tank along with the solution of theliron, t can better be performed 'asa separate s ep after the liquor is vdischarged from the electrolysis cell- A and beforeit is put into the soli'ition plication Serial No. 427,541, reference is made to an application Serial No. filed by us July 7, 1921.

We clairnz-Y l. The art of -making electrolytic'iron which comprises reducing a ferrie solution by means of an electric current to a ferrousieaeee,

state, and then transferring the ferrous lution to a separate electrolytic cell lto which the ferric. solution has no access and de positing iron from the ferrous solution by electrolysis in said separate cell.

2. The artA of making electrolytic iron which comprises reducing a ferric solution by means of an electric current,v leaching au iron ore with the reduced solution, and de0 y positing iron from" the leach liquor by.elcctrolysis.

3.. The artl of making electrolytic iron which @reprises reducing a ferricnsolutionmisf by means ofen electric current, leaching an oxidized iron ore with the reduced solution and depositing iron from the leach liquor by electrolysis.`

' A. The art of making electrolytic iron which comprises reducing u ferrie solution by means of an electric current, leaching un iron ore with the reduced solution, neutralizing the solution und depositing iron therefrom by electrolysis.

5. The art;- of. markingA electrolytic iron which comprisesv reducing ferrie solution by means of an'electro current, leaching an iron ore with the reduced solution, maintaining the solution at :1 temperature in the region of the boiling point und depositing iron from the solution While hot hy electrolysis.

l. ign/eu by us this 5th duyoi" July, 1921. v

FREDERIC A. EUSTIS. CABLE R. HAYWARD. HENRY M. S-(IIILEICHER. DONALD BELUHER.

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