[ iCHl The resent invention is in the technical field of pyaametaliuray and relates te method of producing refined ar nitrated feiromangaoese alloye or metal so o DC are free ace.

[000 | nlaaganese is usee , principally, in steel and staiatess steel production .

[0003] Tradltlonaliy high grade o yaanese products na if a Idle content in excess of Seed and less Pea a 07 5% carbon) were predoced la an alammoabearse process in reaction eesseis, I ^:; ar7 ant manganese allay grades (with Ma caateot between 76 ^■■■■ 95% ; such as low (less than 0.6% carbon content) and medium carbon beam meases so from 1 -2% carbon content), hereinafter rofeaad la as 1 F em%" and ^:: tyiCbObtrv' respectively, and war© produced via a s!iicontheee!c process In n atal ladles. Th:s process has ragh cost Implications,

[ 004] The bulk of manganese product produced today consists of low or lewc:" grade high carbon feuaseaaganese tbiC mkTv}.: of feraesCeoewaioeimse ( eJVlnSi ^ss } _; with b n content of between 60 - ^■ 80%, which principally a produced ^' employing carbathernric reduction in an AC moeneetgeo ^" arc furnace. ί00δδ| To improve upon the HCFea n or FelVlnS; grades various additional steps are required, repairing further eapltal ex enditure Iran additional processing capacity to aeeemmodate these steps. [0006] For example, T the reduction of the carbon content or HCFeFin. the crop, tapped irem the AC arc furnace reports to a converter tor oxygen mrleing m vouch carbon is burnt off, Tree disadvantage e that the process step resets w c high (1 5- 20%) loss of manganese through its vaporlxed oxides.

[00071 Another example of a multiple production step process en ployec m the state of the art. necessary to achieve a high grade product from metallurgical grace nvsnyarwse ores, is an are-llrne melting step In ar- arc furnace followed by svlcothsrrnlc reduction dicing a molten evixlnp step, employing the Renin process.

[OOOiJ The invention asms l:e at ieast partially address the sforerneeheeeci problems.

[ 009] Herecvefter, "a high grade manganese product: ^' means r alloy or metal product. In which manganese Is present In a concentration of at leas! 76% (m/mV arc;; car-ben ;s present In a concentration less than 2% mpop.

C0010] The Invention provides for a pyrouwtallurglcal method tor producing a first high grape a oca msec product by reducing a manganese oxcie reacts ni . Irs a test, reaction zone within a c. ;o rem vessel DC! arc furn ce, with a reducing agent w an inert or nitrogen rich atrnespnere.

[001 i j The manganese oxide or acta of may be Input io the furnace as pa t of a ί 0 D 121 ] ^" he reduction may be alumirmthermm wherein the reducing agen s elemloaoe added to t ie furnace as part of the charge in a arse granulated form te ^¬ as chips,

[0013] The tee υ mi on may be slllcotherrosc, wherein the reducing aga f is slllcao or ferroessocn. Preferably tr e ferroslNeon Is of a grade FeSi 75.

[0014J The first reaction acne may be a sollu/tlqald phase comprising cf e slag layer and an underlying eietsl/alioy layer, Odl SI The temperature of the erst reaction soee may be In a range l o00 ^';': C lo IPeiPC fb ^' eferabha the tem e atu e range o? the reacbon aone is 1 700 ^'::' C to leOCeTT

|0ϋ1β] Trey first high grade .. manganese product may be manganese or a bete or ferroseoo alloy of manganese.

[0017] The Inert or estrogen rich atmosphere ^■ may bo achieved- e imtodmrng. ia ao Interior of t e closed vessel DC arc fumaca _; an men. gas or ni ogen respectively. The Introduction of the men gas or nitrogen may purge the vessel of prior gas content. Preferably, nitrogen Is introduced to mak u : at mash 95% of the atmosphere.

[00181 A second mgh grade niaeganese product may be produced by oxidaean cf a. vapour of the first loon grade manganese product, for usancee -meoriaee mamgaoese, a second reaction zone, veth irogeo,

[00101 The second high grace rnancanese product may ae a manganese ohrlda. 1002.0] The manganese nitooe may be one or more of the following . nN, Mn$ ;- _s dryhT rOr; _¾ N; _; and naa. Preferably _: the arytjanese nonde so olcoN.

[0021] The second reaoaoo zone may occur ithin a gee hase The second, raaouoo zona may be located above the nqeid/soHa phaaa within the furnace and may extend to an off-gas ioaated within an off-gas conduit which removes an off- gas from the furnace.

[0022] The temperature of the second reaction ser e may be be w l oiTC. preferably ct a range uOCoC to 1 19CTC. 0023] The maogunese nitride epay co extracted from the second reaction cone and separated irorn other off-gas content by mf ration. 0§24] The tirterea manganese nitbde may be reanad or recycled to tine furnace os part of the charge, ddlSj The first high grade manganese product and niangaaese nitride, may be refined by passing a refining can through a aessei (ladley containing rrioifeo product ar ooodo _; and allowing the refining gas to percolate it ^; rough the product or i ,0":U;, ^" > .C)026j The refinrng gas may be oxygen or ao. 00271 ^"r de ncaagaoese oxide reacts nt may be an one preferably a oa cinod ore. The ore may be one or more of the following: pyroiuaihe brairnTo haasnweoite, rhodonite _* psilonvelane, rnaoganite rtmdooraosi o ana aracanoeakTo [002S] Atferaatrveiy, the manganese o ide rescfant may be or manganese nerewa waste stream, for sxacyple a dust or sludge asLo stream or a high grade slag.

[00281 A fluxing agent may be hit reduced, web the charge, to the brraaee ia control one or mere of the following pararaeiers: the viscosity of the slag layer; are melting point of the st g l er, the capacity of the siag layer to absorb phosphorous and the capacity of the slag layer or absorb solphcm 00301 The dax g agent may da CaO. gO or SdA based.

[00311 The in ention is aether acscneeo by way of example with refe ence ta Ida accompanying drawings w erehr

Figure ^' i is a process diagram., which Includes the nielloed of the leverblom Illustrating major egyspraent ana process flows; ace

Figure 2 is a process flow diagram focussing or; the process steps of the method a? the nvention.

[0032] Figt.ce 1 of the accompanying drawings illustrates a process a), wlern Includes a method of the invention ltd illustrated in greater ^' de il -n figure 2. in which a high grade manganese product 14 Is produced from a nmaganeoe exam |0033] Hie manganese oxide input I S can be an ore _; such as. tor example pyrotuslte, braunite, hausraanrria, rhooonPe. gsHomefaae. rnanyar e, rhodoehioshe and mangsnoeakdte. The manganese oxide Inpol can also be manganese bearing waste stream m:cn as oust sludge or a high grade slag. Preferably, an ore such as pyroluslte (h1rr0;d ;s used in the process 10.

[C 0341 Ore mafebal Is temporarily stored In stockpiles 6 before reporting to a separator 18 widen separates an oversize fraction from a sized fraction 20 of the ore rnateriah This si ed fraction Is wran to a calciaer 22, with or wrihonr the addihou of limestone menemtlng upon the ore typed and me::.; oc:! ?o thermally decom ose the oxides, each as pyroieslte _: or carbonates, snob as rhodorxte, of the ore., removing volatile Tactions and producing a manganese ore. of a o e stadia osldatlomsfate; In ac doing, the possibility of eruptions when the ore Is smelted (a step which whl be described below) Is substantially reduced . f003S] Also,, this s an important step ;n the firming process which a/iil be described below in greater defaT

[00361 he calcined ore 24 reports to a batching system 20.. which intdaaes plurality of Iropgers, respectively designated 2BA. 2SB, 28C , . , 2820 each of reach a dedicated to rear. I so a furnace feed mgmde t one of which Is the calosreo ore 2-0 The other furnace feed ingredients include a fluxing agent 3D ami a reducing agora. 32, in the form of granules or sized scrap, which ;n das particular embodiment is aluminium , in other enrnw earns of the invention, employing sTe teuTale reduction, the redticing agent 32 can be silicon., metal or. preferably a feaoar!oon known as FeSI 75. |003?1 The Im ortance of fluxing, how -fluxing afters important process pa ameters and thp types of fluxing agents 30 us ecu will be more fully expiarnec below

[0038] Recycled product froni the smelting process, such as manganese ni rides, can be input to the furnace feed at this stage This will be explained below In more

[0039J in He batching system 20. each hopper releases Its respective content, of ore 24, fluxing agent 30 or alumlreum 32 at a predefined power to feed rate rape. Into a mixer 34. which mixes tie:: feed ingredients sen a feed me: 33 before release to a DC mat; or: a or tilt g DC arc ! urease 36.

100 1 The cuxx.es of the invention 12 employs stationary orbiting DC arc Ouosce 36 which l as a dosed vessel body 33. The roof of tret dosed vessel body a pierced by a plurality of toed chutes 40\ through which he teed ram 35 Is introduced to an Interior of the furnace 3n and an off-gas duet 42, through, which gas and dust partsoies leave the furnace. h.v electrode 44 (see Figure .2). carryiryg a DC current, penetrates the vessel 38 to termi a e, at an Interior end 43 ₁ lust above ar ^; even bath 48 of furnace s: net content. The vassal body is further penetrated, at respective sides, by a metal and slag tapboie _; respectively designa ed 50A and 50B _; (or In the ease of a tlrbng t)Ct furnace, a single pouring spent 301, througb which a metal or elioy product 51 and elan 62A is released from the furnace.

[0041] The cues bath 43 comprises an upper ^' queH d slag layer 62, of flux and elomlnium oxides, at a temperature typically In the range 1700 · 1800 ^::' C aun ¾ lower metal layer or alloy layer 54, at a vwwomturc typically In the r nge 1600 · ^■ 17QCFC. [0042] In use of the furnace 56 nitrogen 3? is passed sofa the vessel through one of the faeo chutes 405 alternahvem through a channei in the electrode 44 _: to purge the infe io or the vessel 38 of any pre-existing gaseous content and replacing t inferior of the vessel volt; an Inert atmosphere a ade up ol at least. 85% nitrogen. With lithe or no -oxygen, the ροχχ ^χχ ον of manganese ox d sing to undesirable manganese execs is significantly redueeo.

100431 in the smelting process in the vessel 35. temperatures exceed 20G0 ^':' C m the are between electrode 44 and open nap; 48; the fed ^' mi iegjefies. reacts and separates between the slag lager 52 and the n etai/ahoy iayer 54. f§044] The reactions which are teklng place in an interface between these layers are: rpOy X Ai -> IVtn r W¾ -r Mrpg) (equation 1 ) if the reducing reaction is seem reman, the reaction equation is: nafy w geSI % ^■ bin SICo ÷ Ivtraig; {equation 2} rOCMSj The moifea manganese rneiaL or ferro-miloy of this neetaf settles from the interface into the metal layer from ceo: re it can be rapped off or taphele 50Λ from where the metal or alloy product enters ^' a refining stage ana a final product shwig process 55 before dispaiah as a final product 14.

[0846] With the open hath 48 of the h)C furnace 36 _f manganese will ume off the Path, represented in the above equations as the manganese gas product _; and pass directly into the mlTogen nob gas phase above the bath. Here, tea temperature above the bath is too high for toe manganese to react with Pat nitrogen. [0Q47J eaction n ^:; the gaseous manganese occurs where the tecum rate m is in a range BOO T) to 1 l OCrCP A prop in temperature ie it in ties range occurs ie off -pes toned in †r:e off-pas duct 42 _: between a ^" furnace ctf-pias outlet 57 end a dry pas cleaning facili y 58 t hereinafter referred to as a ^" gas reaction cone" ;. To ensues a drop in temperature from ao-out i 70fwC, above the bath 48 of t ie fu rnace 36. to s iernperarure wrihln the abosrocensoeec ranee, the eft-gas stream within the gas reset ion zone o temperature gnenoheo with a nitrogen stream 58 produced in the gas cleaning oeoilty as wiii be more fuiiy described belo

|004S1 Within the gas reaction zone , the manganese wiii react wPn nitrogen as represented in equation 3 below.

|yfn(g i f 1% 4 hwop (eqoatlori 3} n -s r¾ · > ^■■ iyioT e ation 4 )

|0o4§] Tfre nitride synthesis process, represented ^; n equations 8 and 4. can produce one or more of -many possible manganese nitride orooeofs, such as; iVin id . ni;N>- _. ; _; ssnsNc _: fTire and Pli¼ . The eventual ^" product, or cccktaij w o;P loe roducts, whioh results from this part of the process wiii depend upon the variables of tpmperafi;re and the nitrogen to m nga e e concentration ratio Therefore varying these parameters will vary the composition of d e nit ide produol . Those parameters can be controlled by controlling the rate and the temperature of the nitrogen so ores 59 recycled from the facility 58. The preferable product ^; s fw r N . f OiOl These manganese nitrides are solids., which in the form ot iisf. particles , report to the tome abatement and dry gas cleaning facility 58 as part of the off-gas stream , in the facility, the manganese nitrides are separated from the gaseous (00471 Reaction of the gaseous nzwar om: occam w ere the tem rature e> m a range 800 ^* 0 to 1 1 OCT;, A crop in temperaiore to wit in this range occurs in off gas found sn the eft-gas mar ·<ΡΡ between a furnace ofagas .out et 0? and a dry pas cleaning facility 58 (hereinafter referred to as a "gas reaction zone ^"' }. To ensure a drop in temperature tram about TrOOTT above the bath 40 of Pre fameoe 3o _; to a temperature within foe abovemenilooed ranee, the ofbgas stream whiza the pas react on zone is temperature quenched with nitrogen stream 59 produced in the gas cleaning facility as wiii be more fuiiy described below. f004i] Within the pas reaction zone, the mang ese n react with nitrogen as representee m e u tion 3 below, fdnCg) a N _¾ m iwdhb (equation 3) bin ·τ Ms - ruddy {equation P f f¾04Sl The minus synthesis process, represented in equations 3 and P . can produoe one or more of many possible manganese nitride products, .such as: nfT ru _& nuzPn. iv¾N and n.o . The e entu l product., or cocktail of nitride prodacis, hich results Item if us part of the process will cioponci upon the vaaardes of temperature and the nitrogen to manganese concentration ratio. Therefore varying these parameters will vary the composition of the nitride ^. product, These parameters can be controlled by controlling the rate and fire temperature of the nitrogen stream 59 recycled from the facility pp. The preferable product ;s efrpTd fOOSO These manganese nitrides ru e sol ds _: which in the fo rn of dust particles, report to the harm abatement and dry gas cleaning facility 58 as pari of the off -pas stream, in the facility, lire manganese nithces are separated fro -he gaseous components of the off-gas stream, on a series of High temperature ars {not shown) housed within the facility 58. T ^' he nitrogen stream 59 is inns produced by the separatism with this stream channelled back to the gas reaction zone in the of 6 gas duct me some of this streams being released to the atmosphere, dye mount depending upon m ps m a This ;s illustrated in Figaro 1 . O Si ^' l The filtered, separated manganese nltnde pardcies 60 tod into collection funnels 82, beneath toe facliity S8. to be channelled aiong ana of two optional processing streams: a recycle stream 64, or a redoing stream 66. These wry streams are Illustrated in F gure 6

[66S2J The recycle stream 64. comprising the manganese nltnde product 66. reports to the batching system 26 to ro i part at the fed mix 35 as reqused hire product 66 of the refining stream 66 reports to e ladle pas refining system 66.

|66i3j The manganese .nitride product 58 can be an important component of toe fed mix 3d to monism the mesons parameters of the smelting process with n the furnace 36. As examples of this regulation: should higher concentrations yd manganese be required in: d fed mix 36. and ultimately In the end product 64; and should em temperature need to be mo unco within the furnace: manganese nitride can be recycled into the feed mix. T ^' he manganese nitride has a temperature quenching effect, an Important function when the temperature within the furnace 36 needs to be optimally regulated. 054| The manganese nitride pmdaet 66 is e high grade manganese product m Itself. T ^' he product 66 can he mechanically agglomerated, aided by the use of hinders, and sold as briquettes or pellets. [DOSS] The gas rePrang eastern 68 is interposed between tea furnace 36 ana Pa; enai sizian pracess 55. in the process of gas refining, the moiten raetai aiiay a- tea oca; taphoie 50A into a iaoie ?D (or a series of iaeies) which has a paraas ceramic aiaa at as ease. it is through this porous l g that a refining gas, Poai a gas streaia 72 _; permeates the inane to pewsiale through the sawon rneiai alien content 74 of

i OP 5 at he refining gas, principally, comprises oxygen . This gas sen aiaa be an. Percoiafing exygee through the isdie content 74 has the effect at oxidising P impacties or contaminants tyeieaPe ^' anna in a manganese rnetei / aiiay semi ^; , product, Eaarnaies of Phase aaataaiioants include Ca . hasp ha Ai . Til Si aaa VP Oxegea wiii oxidise these eantaraiaares to their respective oxides which wiii combine to farm a discrete stag layer 76 atop the ecaa / aiiay layer ha that can Pa a ed eft as a slaa stream SO aaa hiaca Pac Ilia now purified mean / aiiay aaa Pa tapped aft as a high grade raaaganese product 14. which apneas fa the sieina pracess aa before dispatch and saio.

[0067] Sulphur and phosphorous are camaaon nereraelaPc aantaeiinaias ai a ioetai/aiiay araaaat- The reduction of these cantaraiaaats in the matai/aiioy predeel. is achieved ay desaiphsrisalieo ana aephasahensafien respectively whereby haxare (described below) is used ta increase the capacity of toe siag iayar ap e> absorb these eoneaaiaaals resulting in the neaew a uww raa heave available ta contaraieaie the product. 14,

ΙδοΡΡΪ] The refirsaa aaa caa include inert gasses in a aaa oas ta reduce the paces ureas w e of CP aaa CO arid aid in aPrriaa the ceaienis 74 of tea iodic 70. f0666J The com osition of the flexing agent 30 Infroclueed to the freaane 36 as part of one ocs mix Id; ;s an m ortan variable n> the smeihag p oc ss eras consequently., to the efficiency of this process and ultimately the rvmnooshlen of tire product 14 hoed

[0060] Raxing of a slag is done to reduce the melting point and viscosity of the Day layer 52. This has the enact of improving manganese metal or alley recovery- by rodncing the aianganese oxide content of trie slog layer 62 and, h r r duced viscosity of this layer, allowing toe. metal/alloy product 14 p.: separata from tire clap I n nance and settle, by grawly ami the additional forces c e ted by the 130 coupling or current flow ( ^' from catnode/eleatrade to anode). Into 6a, metahalloy layer ^' 54 tin recovery.

[0661] line type of fluxing agent need Is dependent open tire original ore mineralogy o the ore and elemental analysis hTrvawlegy ami ele ental composition vanes considerably between roe bodies,

[00621 Lime (calcined limestone (CaO)} or dollrne (oelcrneb dolomite ^' dogCry are used as fluxing agents 30 of choice to flex g-eduee melting paint of) a SlCg rich ere (acid ore) or when the slag layer 62 has a hlgn alumina (ArgO h contend

[0063] Silicon -oxide (SiOD; Is used io flux a basic CaO or gO nob ere.

[0064] Donee the alumlnothnmrce reaction explained above, alumina Is produced. This component of the slag layer- 52 has an extremely high melting point (hgeefies at sCDO t.h. Therefore to operate at 1750 C In the slap layer 5th which is a preferable teniparafure, an appropriate mix of CaO/MgO e SICD, as a fluxing agenu needs to ae added. C!SSS] The value of the sulphur partition coefficient usua ly usee ;rh an Incre e in CaO content m slag. time additions will therefore increase the sulphur capacity of the eae . known as desidphabsatlorr and as the- slag Is discerdoch this prevents or mlnirnlses sulphur adsorption by the meiaballoy product yCaO S ·· ^■ Chad -· ^; - Or

[0066; Depbospbi:uisatien Is the capacity of the slag to absorb phosphorous Tier distribution ratio of phosphorous between the CaO-Caf 2-Si02 bearing slag and metal increases with increasing CaO content. Therefore both CaO and GaF2 wiil reduce phosphorous- contamination or Oe niefafOlloy product 14.