US1299559A - Method of extracting and recovering molybdenum from its ores and concentrates. - Google Patents

Description

H. A. DOE-RNER.

METHOD 0F ExTRAcTlNG AND RECDVERING MDLYBDENUM FROM ITS DRES AND CDNCENTRATES.

APPLICATION FILED JAN. i8, 19H.

. l norman, or DENVER, comme.

Maraton or. nx'rnectrme AND nncovnnme MOLYBDENUM rnoiu Irs onus lArm concrmnarns.

exact description of the invention, such asv will enable others skilledV in the art to which it appertains to make and use the same.

rIhe present invention relates to a method' for the extraction and recovery of molybdenum from its ores and concentrates; and moreparticularly to the recoveryo molybdenumoxid of commercial purity from .ores or concentrates; and especially from those ores and concentrates which contain copper or other deleterious elements which are not .separated by the usual methods of treatment'.

I have found that when molybdenum ores or concentrates or other appropriate molyb- 'denum-containin materials are heated with va suitable chlori to a sucient temperature to fuse the same and under proper conditions the molybdenum will distil ed in the form of volatile chlorids or oxychlorid's; and thatrom the distilled product molybdenum oxid can be readily .obtained by the action of water 4or steam, hydrochloric acid being atv the same time set free.

4In the practice of the invention, -the molybdenum-containin material, such as the molybdenumxsul ore, molybdenite, mixed with a suitable chlorid such as ordinary salt (sodium chlorid.),-is heated vto a suicient .temperature to form a fused bath and under appropriate conditions for com-v the chlorin bining the molybdenum with o' the of the ychlorid 'and for' distilling lresulting chlorids or oxychlorids thus formed. 'The action is promoted' by carryp ing out the operation in an oxidizing at-4 mosphere.

In the preferred practice of the invention, I use .a fusible chlorid, such as sodium `chlorid, and electrolyze a fused bath ,conA- taining the chlorid and the molybdenum Specification of Letters Patent.

Patented Apr. 8, I9I9.

v Application led January 18, 1917. Serial No. 148,081.

ore; and I will describe my invention more particularly in connection with such preferred embodiment.y

. In the accompanying drawings I have illustrated a suitable type of apparatus/for e'ecting the extraction and recovery of the molybdenuml by the use of a fused bath contalning the molybdenum ore and a chlorid suchas sodium chlorid.

cast iron or steel box 1 divided into three compartments. lThe hearth 12, vWhere vthe,- fused salt is decomposed by the electric current, has itsoorcovered with' a layer of a Huid metal such as molten lead which is adapted to combine with an alkali metal such as sodium to form an amalgam. The molten lead Hows continuously to the lWell 3 from whichv it is ejected by means of steam introduced through the pipe 9through the ipe 10 and into the chamber 11, from where 1t Hows 'back through the channel 12 to the hearth 2. v

v 'Ihe hearth is linedv with magnesite bricks i and is held 'in the fire-clay setting 5. @ver the hearth are thecarbon or graphite anodes a suspended by the terminal rods 7, which pass through the lire-clay cover 6. 'Ihe molten lead forms the cathode and is connected with the terminal 8.l

The gaseous products are drawn 0E from the-furnace through the flue 13 to suitablecondensing chambers (not shown). The furnace is provided with covers 14 to close the openings through which the material is introduced into the furnace; and with a taphole 1 5 to enable the moltencontents of the furnace to be drawn-od as desired,

In the preferred-practice of the invention, a `mixture of salt-and molybdenum ore is ted to the furnace .and a directcurrent of suitable voltage and amperage is passed decomposed therein into molybdenumV oxidand hydrochloric acid by the action of steam -or Water. This decomposition of the molybdenum chlorids and the formation of the oxids and hydrochloric acid may with advantage 'be' carried on in the condensing chamber itself. The hydrochloric acid canbe separated by evaporation or distillation and recovered, leaving behind the molybdenum oxid.

inasmuch as molybdenum also forms a number of oxids, as Well as a number of chlorids, the final product Will vary according to the variations in the chlorid distillate.

With o res containing sulids, such as molybdenite, air may be admitted to oxidize the sulfur and thereby assist the action of the chlorin with resulting economy in the use of the chlorid. Thus, Where, under nonoxidizing conditions the sulfur ,l of the molybdenum suld may combine with the chlorin to form sulfur chlorid, under oXidizing conditions it may be oxidized to sulfur dioxid so that less chlorin is required for the reaction. The oxidization of the molybdenum sulid, and the action of the sulfur dioxid in setting free chlorin, which may supplement or replace the electrolytically formed chlorin, Vmay be illustrated by the following equations: v

The chlorin is moreover set free Within the reacting mass Where itcan combine with the molybdenuml to form volatile compounds. Molybdenum can thus be removed which, if no such chlorin were set free, would tend to remain in the slag in soluble form.

The setting free of the chlorin at the anode is accompanied by liberation of sodium at the cathode, and this sodium amalgamates with the molten lead to form an amalgam which flows to the Well 3 from which it is ejected by the jet 'of steam into the chamber l1, being decomposed by the steam into molten lead and into sodium hydroxid,V

which, at the high temperaturesused, is obtained in a fused and anhydrous state. The

Lacasse decomposition vof the steam by the metallic sodium to form the sodium hydroxid is accompanied by the formation of' hydrogen which may be drawn off and allowed to es. cape or utilized in an auxiliary heater or for other purposes.

The fused caustic soda accumulates in the chamber 11 above themolten lead and overflows the lip 17 into a suitable receiver (not shown). The impoverished amalgam con- 'sisting mainly of molten lead which has been further heated by the reaction of the steam and sodium, flows ,back to the hearth 2 through the channel 12. The molten lead cathode is thus circulated from the hearth to the Well 3.and `back to the health, combining with the sodum set free from thebath and giving up the sodiuml on treatment with the steam.

The heating of the fused bath'canbe effected by the resistance of the current passed through it, and the bath can thus be kept at the proper temperature by proper regulation of the current; but the heating action of the current may' be supplemented by an auxiliary heater, and particularly by the use of such an auxiliary heater to preheat the salt and ore mixture which is fed to the furnace.

Fusion of the salt and ore takes place at a temperature slightly above 800 C., and I have found a temperature of about 000.o C. a satisfactory operating temperature for the molten bath.

While l have described ajtype of furnace particularly adapted to the' practice of the invention. l do not desire to limit myself to the use of any particular type of furnace oreven to the electrolytic decomposition of the chlorid in a fused bath; although such an clectrolytic procedure, using a molten or liquid metal cathode, l consider to be a particularly valuable embodiment of my invention and one having many advantages.

When the invention ispractised Without -the electrolysis of a fused bath, a mixture of molybdenite andl salt, for example, can be heated to the proper temperature in any suitable manner and subjected to an oxidizing atmosphere so that the chlorids 'or oXy# chlorids of molybdenum will distil 0H in a manner similar to that which T have already described. Thus, for example, Where the mosphere by injecting air into the fused bath, the sulfur dioxid formed by the oxidizing atmosphere and the sulfur of the suld (molybdenite) reacts with more oxygen and with the salt to form chlorin, which combines with the molybdenum to lform volatile compounds that distil off in 'a manner similar to that already described. Tn this 'case the reaction of the sulfur, oxygen (from the oxidizing atmosphere) and salt, furnishes ico `mixture of molybdenite and salt is heated to fusion, and'subjected to the oxidizing ator sets -free chlorin which reacts in 'much the same manner as the chlorin set free by electrolysis.

When the electric current islused, its action, aside from its other advantages and functions, assists the distillation and is a convenient metliodof maintaining the desired ,temperatllre` It. has thev further important function, when used with a fused bath, of decomposing the chlorid and supplying active chlorin to the molybdenum of the'ore, as well as of furnishing metallic sodium and caustic soda.

' l While I have described my invention more particularly with the use of sodium chlorid, it will be understood that other suitable chlorids, fusible. or. unusible, are adapted for use in the process.

I claim:

1. The method of recoverin molybdenum from its ores, concentrates an other molybdenum-containing materials, which comprises heating the material to a sufficient temperature to form a fused bath and subjecting the fusedl bath to the action of'free chlorin under proper conditions to combine with and .to volatilize the molybdenum as chlorid or oxychlorid; substantially as de-l scribed.

2. The method of recovering molybdenum from its sulfid ores, concentrates and other molybdenum sulid containing materials, which comprises heating such materials in the presence of a chlorid to a sufficient tem- A MS the presence of a source of chlorin to a sufficient temperature to fuse the same, and to set free chlorin and under proper conditions to volatilize the molybdenum in the form of chlorids or oxychlorids and recovering molybdenum oxid therefrom by the action of steam or Water; substantially as described.

d. The method of recovering molybdenum from its sullid ores, concentrates and other molybdenum sulfid containing materials,

which comprises heating the material with a chlorid to a suflicient temperature to fuse the same and under proper oxidizing oonditions to set free chlorin and to volatilize the molybdenum as chloridl or oXychlorid and recovering molybdenumoxid therefrom by the action of steam or Water; substantially as described.

5. 'lfhe method of recoverin molybdenum from its ores, concentrates an other molybv denum-containing materials, which comprises heating the material with a chlorid by means of an electric current to a suflicient temperature to form a fused bath, and under proper conditions to set free chlorin from said chlorid Within said bath to combine -with and to volatilize the molybdenum as chlorid or oxychlorid; substantially as described.

.6'. The method of recovering molybdenum from its ores, concentrates and other molybdenn-in containing materials, which comprises electrolyzing the fused bath containing such material and a chlorid to volatili'ze the molybdenum as chlorid or oxychlorid; substantially as described.

7. rlhe method of recovering molybdenum from. its ores, concentrates and other molybdenum-containing materials which comprises electrolyzing a fused bath containing such material and a chlorid to volatilize the molybdenum as chlorid or oxychlorid and recovering molybdenum oxid from the volatilized product b y the action .of steam or Water; substantially as described.

8. The method of, recovering molybdenum from its ores, concentrates and other molybdvenum-v containing materials, which comprises electrolyzing a fused alkali chlorid bath containing such material, using a fluid metal cathode adapted to form an amalgam with the alkali metal, and thereby combining the molybdenum with chlorin and volatilizing the molybdenum chlorid or oxyc-hlorid thus formed, and at the same time forming an amalgam with the cathode, decomposing the amalgam to form caustic alkali, and returning the impoverished cathode metal for the formation of further amounts of a'malgam;,substantially as described.

9. 'The method of recovering molybdenum from its ores, concentrates and other molybdenumcontaining materials, Which com prises electrolyzing a fused alkali chlorid bath containing-'such material and thereby volatilizing the molybdenum as'chlorid or oxychlorid, combining the alkali metal set free with a fluid metal cathode in the form of an amalgam, and recovering molybdenum oXid from the volatilized chlorids by the action of steam or Water; substantially as described. I

i0. The method of recovering molybdenum from its ores, concentrates and other molybdenum-containing materials, which comybirises electrolyzing a fused sodium chlorid ath .containing such material, under oxidizing conditions, and thereby decomposing the sodium chlorid and combining the chlorin with the molybdenum in the form of volatile chlorids, separating such volatilized chlorids and recovering molybdenum oxid therefrom by the action of steam or Water,

combining the sodium set free With a molten lead cathode'in the form of an amalgam, de-

composin the amalgam with steam to form caustic al ali and to recover the molten lead in an impoverished condition, and returning the impoverished metal for combination with 5 further amounts of metallic sodium; substantially as described.

11. The method of recovering molybdenum from its ores, concentrates and other molybdenum containing materials, Which commeuue y bine with a'ndxto volatilize the molybdenum.

as chlorid or oxychlorid; substantially as described. Y .15

In testimony whereof I affix my signature.

HENRY ALFREDDOERNER. i

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