US917176A

US917176A - Method of recovering metals.

Info

Publication number: US917176A
Application number: US45360708A
Authority: US
Inventors: Walter O Snelling
Original assignee: Individual
Current assignee: Individual
Priority date: 1908-09-18
Filing date: 1908-09-18
Publication date: 1909-04-06
Anticipated expiration: 1926-04-06

Description

W. 0. SNBLLING.

METHOD 0F RBGOVBRING METALS.

APPLICATION FILED SEPT.1B, 1908.

Patented Apr. 6, 1909,

l iN

trimaran srnrns riarnivr onmon WALTER O. SNELLING, OF PITTSBURG, PENNSYLVANIA.

METHOD 0F RECOVERIIING- METALS.

Application led September 18, 1908.

T 0 all 'whom 'Lt may concern:

Be it known that I, WALTER O. SNELLING, a citizen of the United States, residing at Pittsbur in the county of Allegheny and State of enns lvania, have invented certain new and usefullmprovements in Methods of Recovering Metals, of Which the following is a specification.

The object of this invention is the provision of a method of recovering metals, in elemental form or as solutions, from their ores, and more particularly from electricallycollductive ores. The method is especially adapted for the production of metallic tin from cassiterite and will be described by reference to this particular a plication. The method is however genera ly applicable to such ores as are reducible at the cathode in an electrolyte capable of liberating hydrogen.

-According to my method the ore, as cassiterite, in suitably subdivided form or in its naturally occurring forms as stream tin, Wood' tin, etc., is disposed in contact with an electrode in an electrolyte capable of liberating hydro en. Upon passage of a suitable current re uction of the ore occurs and a part or all of the metal is set free: thereafter the reduced metal is constituted the anode in the same electrolyte, and the metal is dissolved therein and is either deposited upon a suitable cathode, or under suitable conditions is retained in solution.

It will be understood that While in operations of this class the reduction proceeds at first with a high degree of efficiency, this efficiency tends to fall as the operation proceeds, the fall of efficiency being proportionate to the amount of current passing directly to the reduced metal instead of to the unreduced ore. This tendency to reduction of eiiciency after the first moments of the operation exists in all cases, but is more pronouncedinthe treatment of such compounds as are relatively difficult of reduction, easily reducible compounds being more efficient as depolarizers. If the current were melf y reversed in the solution after a certain quantity of metal had been reduced at ythe cathode, and a ain reversed when this reduced metal had gbeen dissolved and redeposited, no useful purpose Would be served, for the metal deposited u on the initial anode Ywould be again dissolved? Therefore in proceeding according to this plan it becomes necessary to remove the deposited metal at the close of each cycle of operations, and such pro- Specication of Letters Patent.

Patented April 6, 1909.

Serial No. 453,607.

cedure is costly and troublesome when the reversals are made at short intervals as is'reuired for high efficiency. I prefer thereore to provide in the bath a third vor intermediate electrode and to so shift the current connections that one of the three electrodes is at all times cut out of circuit. As hereinafter described, this arrangement permits the cycles to be of very short durationif desired, Without hovfever rendering it necessary to remove the deposited metal at correspondingly brief intervals.

Apreferred form of apparatus for carrying out my invention is shown in the accompanying drawing wherein the figure is a vertical section of an electrolytic vat, the circuit connection being diagrammatically illustrated.

ln said drawing l represents a tank or vat consisting of or lined With insulating material adapted for use with the electrolyte selected, and 2, 3, 4, the electrodes therein, the electrode 3 being intermediate lthe eX- terior electrodes 2, 4.

5 is a circuit-changing switch which may be of any usual type.

l6, 7 re resent respectively the positive and negatlve leads from a vdirect current circuit of loW potential.

Assumin the electrolyte to consist of hydrochloric acid, the several electrodes may consist of raphite: in case sulfuric acid is employed, lead may be used: or a suitable alkaline electrolyte, as caustic soda or sodium stannate, may be employed, in Which case the electrodes may be of iron. The plate 2 serves as the anode during the reducing stage, and the perforated plate or screen 3, or the charge thereon in case the ore is conductive, as the initial cathode. When the switch is in the position shown in full lines the current will traverse the bath in such direction as to effect the reduction of the ore, as will be readily understood. WV hen the eiciency of this reduction shows a material decrease as Will be the case after the exposed surfaces-have been reduced to metal, the switch is moved to the position indicated in dotted lines, whereupon the current Will pass from the reduced metal in electrical connection With the late 8 to the plate or pan 4 as cathode, issolving the metal and redepositing it. Inasmuch as the reduced metal, as tin, is soluble When connected as anode in the electrolyte chosen, While the material of the plate or screen 3 is insoluble therein, under proper current conl 'E l 10 electrode 4, functioning as cathode during the precipitation, may convenientlyT be constructed 1n the form of a shallow removable an as shown to retain metal deposited in oose or non-adherent form.

It will be observed that in the particular arrangement of apparatus described the electrode 2 serves intermittently as anode, and the electrode 4 serves intermittently as cathode, lwhile the intermediate electrode functions alternately as cathode and as anode, the ore undergoing reduction during the irst eriod and the reduced metal being dissolve and redcposited during the second eriod. Automatic means may be employed 5 or shiftin the current connections at inter vals suite to the nature of the ore and the character of the current ern loyed, and the process may readily be rencred essentially continuous in character. It will be4 obvious 80 that the disposition and arrangement of the apparatus may be widely varied without.

departure from the spirit of my invention. 1n case 1t is desired to produce a solution of a metallic salt, for example stannous chlorid, instead of the metal, this may be accomplished by providing an acid electroe lyte, e. e. hydrochloric acid, of such concentration as to prevent substantial deposition of the metal during the period that the reduced ore functions as anode.

I claim:

1. The method of recovering metals from their compounds which consists in disposing such compounds in connection with an electrode in a suitable electrolytic bath and reducing portions of the compound to metal, and thereafter connecting said metal as an-v ode in said bath to dissolve the reduced metal.

2. The method of recovering metals from their compounds which consists in disposing such compounds in connection with an elec- 'trode in a suitable electrolytic bath and reducing portions of the compound to metal,

and thereafter connecting said metal as anode in said bath 'to dissolve the reduced metal and re-deposit the same.

3. The method of recovering metals from electrically conductive compounds which 6 0 consists in connecting such compound as cathode in a suitable electrolytic bath, reduclng portions of the compound to metal, and

thereafter connecting said metal as anode in said bath to dissolve the reduced metal and re-deposit the same.

4. .'l'hc method of recovering tin from its oxid orcs which consists in disposing such ore in connection with an electrode in a suitable electrolytic bath, reducing portions of said oxid to metal and thereafter connecting` said metal as anode in said bath to dissolve the tin.

5. The method of-recovering tin from its loxid ores which consists in disposing such orc in connection with an electrode in a suitable electrolytic bath, reducing portions of said oxid to metal and thereafter connecting said metal as anode in said bath to dissolve the tin and re-deposit the same.

6. The method of recovering tin from its conductive oxid whichconsists in connecting the oxid as cathode in a suitable aqueous electrolyte, and electrolytically reducing said oxid.

'7. The method of recovering metals from their compounds which consists in providing in contact with a suitable electrolyte an electrically intermediate and two electrically exterior' electrodes, arranging the compound of the metal in contact with the intermediate electrode, reducing the same by passing an electric current from one of the exterior electrodes as anode, and then shifting the point of supply of current to redissolve said metal and deposit the same on the other of said cxterior electrodes.

8. The method of recovering tin from its conductive oxid which consists in providing in contact with a suitable electrolyte an electrically intermediate and two electrically exterior electrodes, disposing the oxid in contact with the intermediate electrode, reducing the same by passage of an electric current from one of the exterior' electrodes as anode, and then shifting the point of supply of current to redissolve the tin.

9. The method of recovering tin from its conductive oxid which consists in providing in contact with a suitable electrolyte an electrically intermediate and two electrically ex-. terior electrodes,A disposing the oxid in contact with the intermediate electrode, reducing the same by passage of an electric current from one of the exterior electrodes as anode, and then shifting the point of supply of cnrrent to redissolve the tin and deposit the same on the other of said exterior electrodes.

In testimony whereof, l afi-ix my signature in presence of two witnesses.

VVA'LTER O. SNELLING.

`W'tnesses:

A. L. HYDE, -HUeo ScnLATTnn.