CA2187892A1 - Leaching of a titaniferous material - Google Patents
Leaching of a titaniferous materialInfo
- Publication number
- CA2187892A1 CA2187892A1 CA002187892A CA2187892A CA2187892A1 CA 2187892 A1 CA2187892 A1 CA 2187892A1 CA 002187892 A CA002187892 A CA 002187892A CA 2187892 A CA2187892 A CA 2187892A CA 2187892 A1 CA2187892 A1 CA 2187892A1
- Authority
- CA
- Canada
- Prior art keywords
- leach
- silica
- acid
- titaniferous
- process defined
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/1236—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching
- C22B34/124—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching using acidic solutions or liquors
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/1204—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 preliminary treatment of ores or scrap to eliminate non- titanium constituents, e.g. iron, without attacking the titanium constituent
- C22B34/1209—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 preliminary treatment of ores or scrap to eliminate non- titanium constituents, e.g. iron, without attacking the titanium constituent by dry processes, e.g. with selective chlorination of iron or with formation of a titanium bearing slag
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B34/00—Obtaining refractory metals
- C22B34/10—Obtaining titanium, zirconium or hafnium
- C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
- C22B34/1204—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 preliminary treatment of ores or scrap to eliminate non- titanium constituents, e.g. iron, without attacking the titanium constituent
- C22B34/1213—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 preliminary treatment of ores or scrap to eliminate non- titanium constituents, e.g. iron, without attacking the titanium constituent by wet processes, e.g. using leaching methods or flotation techniques
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Silicon Compounds (AREA)
Abstract
An industrially realistic process for upgrading of titaniferous materials is disclosed. The process comprises the following steps: (i) a pretreatment which has the effect of rendering silica amenable to leaching under the particular conditions of a subsequent leach, and (ii) an aqueous leach in the presence of an acid, the conditions of which are chosen such that silica which enters solution is not hydrolysed or precipitated as a silicate. The pretreatment step (i) may comprise alkaline leaching, roasting or smelting. The leaching step (ii) may be conducted at low solids densities.
Description
~WO 951Z8502 2 1 8 7 8 9 2 PCT/A
T - n~ of a ~I~;tnn; ' ~ ~r;nl The ~resent invention relates to the removal of impurities from a t;e-n;forous materi-1.
.
The term "titaniferoua Aterial" is ~1~ ~Lood herein to mean a material whiah c~-~ntA; nq at leaat 2 wt%
titAni In a l?articular ~ ; the preaent invention yrovides a proaesa whereby silica and alumina are re~oved 10 from a t;t~n;foroua material using an aqueoua leach in the ~,L.se~ce of acid, with the effectivene3a of the leach in removin~- these impuritiea ~ A by the - n_t;r~n of ~Le~ e q and the c~nA; eion~ of the leach.
In induatrial chlorination processea titanium 15 dioxide bearin,-" fe4A~to-l~q are fed with coke to chlorinators of varioua designQ (fl--;A;- ~ bed, shaft, molte~ salt), opor-tecl to a maximum t~ __r ~ in the ran,,e 700-1200C. The at common type of induatrial chlorinator ia of the fl~ ~A;- ~ bed deaign. Gaseous 20 chlorine is ~assed through the titania and aarbon bearin~
char~e, convertin~ t;t-n;~m dioxide to titanium tetr~-hloride ~,aa, which is then removed in the exit ~aa gtream and ~ ~ ~l_ Q~A to liquid tit_n; eotrAAhl~lride for further pur;f;-At;~n and 3?rocoaE~;nsr-The chlorination proceas as ~ nA~-to~ in industrial chlorinatora i8 well suited to the converaion of pure titanium dioxide feedstocks to ~;tAn;~m eetr~-hloride.
~}owever, moat other inputa (i.e. impurities in feedatocka) CaU8e fl;ff;---lt;oq which greatly _ _1;-At~o either the chlorination process itself or the 8~hao~ ont stagea of C A_~At;~n and purification. The AetA-hod table provides an ;nfl; -Ati~ln of the typeQ of proble~q ~n~o -n~orea In 21 87~q~
WO 95/2~502 PC r -- 2 ^
~aaitiOn, each unit oSi inputs which does not enter proaucts contribute~ ~ubE,tantially to the sr~n~ ~t;on o~ waEteE. for tre~tment and A;'31;~ SO_ e inputs (e.g. he~vy_et~lE"
r~l;o~-tives) result in waste c~r;~;cAt;nn~ which _ay 5 require Epe~ t A; ~ 1 in nitored repoEitories.
Pre~erred input~ to chlorination are there~ e hi~h srrade _aterial~, with the mineral rutile (at 95-96%
Tlo2) the Et ~uitable of pre~ent feeds. Shortage~ o~
rutile have led to the devel ~_ o~ other feedstockE.
formed by ~p5~ A~ng n~t~ lly occurrin~ ~1 ;te (at 40-60 Tio2), E,uch aa titaniferou~ slag (apprnY;~-~t~ly 86% TiO2) and ~ynthetic rutile (varlouEly 92-95% Tio2). These ~g ~A;n5J pr~ceEE^~ have had iron re_oval as a prim ry :EOCUE., but have ~Yt~n~d to re_oval of _ ~e and alkali 15 earth i_puritieg, as well aE. Eo_e ~-1 'n;~-m -
T - n~ of a ~I~;tnn; ' ~ ~r;nl The ~resent invention relates to the removal of impurities from a t;e-n;forous materi-1.
.
The term "titaniferoua Aterial" is ~1~ ~Lood herein to mean a material whiah c~-~ntA; nq at leaat 2 wt%
titAni In a l?articular ~ ; the preaent invention yrovides a proaesa whereby silica and alumina are re~oved 10 from a t;t~n;foroua material using an aqueoua leach in the ~,L.se~ce of acid, with the effectivene3a of the leach in removin~- these impuritiea ~ A by the - n_t;r~n of ~Le~ e q and the c~nA; eion~ of the leach.
In induatrial chlorination processea titanium 15 dioxide bearin,-" fe4A~to-l~q are fed with coke to chlorinators of varioua designQ (fl--;A;- ~ bed, shaft, molte~ salt), opor-tecl to a maximum t~ __r ~ in the ran,,e 700-1200C. The at common type of induatrial chlorinator ia of the fl~ ~A;- ~ bed deaign. Gaseous 20 chlorine is ~assed through the titania and aarbon bearin~
char~e, convertin~ t;t-n;~m dioxide to titanium tetr~-hloride ~,aa, which is then removed in the exit ~aa gtream and ~ ~ ~l_ Q~A to liquid tit_n; eotrAAhl~lride for further pur;f;-At;~n and 3?rocoaE~;nsr-The chlorination proceas as ~ nA~-to~ in industrial chlorinatora i8 well suited to the converaion of pure titanium dioxide feedstocks to ~;tAn;~m eetr~-hloride.
~}owever, moat other inputa (i.e. impurities in feedatocka) CaU8e fl;ff;---lt;oq which greatly _ _1;-At~o either the chlorination process itself or the 8~hao~ ont stagea of C A_~At;~n and purification. The AetA-hod table provides an ;nfl; -Ati~ln of the typeQ of proble~q ~n~o -n~orea In 21 87~q~
WO 95/2~502 PC r -- 2 ^
~aaitiOn, each unit oSi inputs which does not enter proaucts contribute~ ~ubE,tantially to the sr~n~ ~t;on o~ waEteE. for tre~tment and A;'31;~ SO_ e inputs (e.g. he~vy_et~lE"
r~l;o~-tives) result in waste c~r;~;cAt;nn~ which _ay 5 require Epe~ t A; ~ 1 in nitored repoEitories.
Pre~erred input~ to chlorination are there~ e hi~h srrade _aterial~, with the mineral rutile (at 95-96%
Tlo2) the Et ~uitable of pre~ent feeds. Shortage~ o~
rutile have led to the devel ~_ o~ other feedstockE.
formed by ~p5~ A~ng n~t~ lly occurrin~ ~1 ;te (at 40-60 Tio2), E,uch aa titaniferou~ slag (apprnY;~-~t~ly 86% TiO2) and ~ynthetic rutile (varlouEly 92-95% Tio2). These ~g ~A;n5J pr~ceEE^~ have had iron re_oval as a prim ry :EOCUE., but have ~Yt~n~d to re_oval of _ ~e and alkali 15 earth i_puritieg, as well aE. Eo_e ~-1 'n;~-m -
2 1 8789~
o 95128502 ~ 3 ~ PCT/~Ug5/00222 t~l Chlnrin~tinn cnn(1~nc~tion Purification Input Fe, Mn Consumes Solid/liquid nhl nri ne, chlorides coke, f oul increases ~ h, gas volumes make sludges Alkal i Def luidis e &alkali earth f luid beds du~
metals to liquid chlorides, consu,m. e chlorine, coke Al Consumes Causes Causes chlorine, corrosion corrosion, coke makes sludges Si A~ t~c Can encourage May require in duct dist; l l At; nr~
chlorinator, blockage. from product reducing Condenses in campaign part with life. titanium Consumes tetrachloride coke, chlorine V ~ust be removed by .-h ~m; CA 1 treatment and distillation Th, Ra A~ st~C
in chlorinator brichwork, radioactive;
- causes Ai cp-~c;ll di~ficulties W0 9S/28S02 2 1 8 7 8 9 ~ pcrlAu9sloo222 In the l?rior ~Art 3ynthetic rutile ha3 been formed from l ~tAn;fe~ro~n m;n_rAlA, e.g. ;l ;te, via v~riou..
techni~ue3. ~A~Anr~l;ng to the moat commAonly a~lied techni"ue, a3 variou31y or-Arnt~d in We3tern ~u3tralia, the 5 titani~erou3 mineral i3 reauced wlth coal or char in a rotary kiln, at t~ _ R in exces3 of 1100C. In thi3 ?roce33 the iron content of the mineral i.. Aubatnn~;Ally Al l; -- J . Sul~>hur addition3 are al30 made to convert r n ~ impurit ie3 pAArt ially to ~ 1 rh; r . Fo 1 lowing 10 re~ At;nn the ~ roduct i3 cooled, 3~rA AAt~d from A _ Q~; A t ~d ch~r, and then . ub j ected to a~ueou3 ; _ or removal of virtually nll ~AnntA;n~d All;~A iron a3 ~a rAhle fine iron oxide. ~rhe titaniAferou,, ~roduct of t;nn ia treated with 2-5% a~ueou,, 3ul~huric acid for 15 "~; _pA~ f; nn oAf _ -8 and 30me reeidual iron. There i3 no sub3tantial 1 removal of A lkal i or A 1 1rA l; n ~
earth3, Al n; ailicon, vanadium or rAA;nn-lAl;ArA, in this ~roce. a na A;-A-lceed or or-ArAted. Further, iron ~nd ne~e removal ia ;- _ lete.
~ecent A;AA,1. .. E~ have ~rovided a ~roce3a which A~re~A~t~ reA--A~;nn at lower t _ ~ .a and ~rovide3 for hydrochloric Acid l~Ah~n~ ~fter the a~ueous AorAt;nn 2md iron oxide 83~-- t;nn ste~a. ~-~AA,rA;nU to A;~103~rea the rroce33 i3 ef ~ective in removing iron, _ - - e, alkali 25 and All~Al;n~ earth i_;purities, a ,A.~hAtAnt;Al ~ro~ortion of Alllm;n; inrut3 ~nd 80A vanadiumA A3 well a3 thorium. The proce33 may be o~AAAAAt~d as a retrofit on ~ ;ng kiln ba3ed ;nRtAll~t;nn~. However, the ~rocess i3 ineffective in full vanadium removal and has little A1- '~AA1 i_pAct on 30 3ilicon.
In another ~rior art invention relatively hi,,h de~,ree3 of removal of ~,~n~Aillm _ --B, iron and ;n;llm have been achieved. In one such ~rocA3s ;1- ;te i3 AfirAt t-h~rr-lly reduced to suhstAnt;Ally ~ _lete 35 reA~At;nn of it3 ferric oxide content (i.e. without -~w09s~l8so2 ~ 1 ~3 78 92 PCr~Aug5~00222 s-lhat~nt;Al -~ll;Pat;nn), normally in a rotary lciln. The cooled, reduced product is then leached under 35 p~ai yreaaure at 140-150C with excess ?o% hydrochloric acid for removal of iron, ~ m~ m;n;~m and r~ e. The 5 leach liquor~ are apray roagted for ,. ~ t;nn of Lyd~ ~ chloride, which i~ recirculated to the lPArh;ng step .
In other l?Loc~nc~ the ilmenite u~Se~,es grain r~f;- by thermal nY;~t;nn followed hy thermal 10 reA--. t;nn (either in a f7.-;A;AeA bed or a rotary kiln) . The cooled, reduced product is then subjected to r _~ ic l~A~h;ng with exces~ 20% hydrochloric acid, for removal of the deleteriou~ impurities . Acid ~ t; nn i~3 also p~-f~ 7 by ~pray roa~ting in thi~ proce~s.
In all of the above ;nnod hydrochloric acid h;ng baAed ~ ~cea~A impurity removal is similar.
Vanadium, Al~m;n;~m and silicon removal is not fully e_fective .
In yet another procesg ilmenite i~ th~^l ly ao reduced (without Al1;Pot;nn) with carbon in a rotary kiln, ~ollowed by cooling in a nnnnY;A; s~inq ~.h~r6:. The cooled, reduced ~roduct iB leached under 20-30 p8i ~auge pres~ure at 130C with 10-60% (typically 18-25%) ~3ul~huric acid, in the 3?` ~ Q of a #eed material which assists 25 hydrolysi~ of di~solved titania, and cnn~ n~ly as~i~ts l~A~h~ng Of impuritie~. ~ydrochloric acid u~age in pl~ce o~
aUlphuriC acid has been claimed for this z~rocess. Under such circum~tance8 5imilar impurity removal to that ~chieved with other hydrochloric acid based systema is to 30 be ~ect-~A. Where sulphuric acid is uaed rAtl;oA~t;vity removal will not be - _ lete.
A commonly adopted method for upgrading of ilmenite to higher grade products is to smelt ilmenite with Wo 95128502 PCrlAUgS100222 coke ~ddition in ~n electric furnace, ~roducing a molten titan$ferous sla~ (for c~sting and crushin5~) and a ~i~J iron ~roduct. Of the ~roblem im~uritie_ only iron iQ removed in this manner, and then only incomrletely as a reQult of 5 compositional limitation8 of the ~rocess.
A wide rans~e of ~ot~Ant~Al feed_tocks i8 available for -rgrA~;n~ to high titania content materials suited to rhlar;n~ti~n . ~ _ lr~ of ~rim~ry titania sources which cannot be E~t~QfArt^rily ~rgrnded by ~rior art l?`C-~88~-10 for the u~ ~^~ of pro~ rt ion of a material suited to rhl^r;nl~ti^n include hard rock ~non detrital) ;l- ;taQ, R;l~reo~R ~ - rR, m ny ~rimary ( - -~hared) ;1- ;tAR
and large anatase resource_ . ~any such R e ~ ry gources (e.g. titania bearinsr slags) also exist.
Clearly there is a r~nR~ rAh~e incentive to discover methods for ll~srrA~inlJ of tit_niferous ~^-tar;AlQ
which can e: cAlly ~roduce high grade ~roduct3 alst irres~ectively of the nature of the im~urities in the feea.
At ~resent ~rc,ll~ce ~ of titania ~igment by the 20 choride ~roce3s require feed_tocks to havs silica levels as low as ~ossible. In general st fes~qQtocL-Q are less than 2% sio~. Where, for various reasons, feedstocks with high levele. of _ilica may be taken in, they are blended against other low _ilioa feedstoclcs, often with significant c08t 25 md ~roductivity prn~lt;~R. Therefore sll~l?l;ara of titaniferous feoARtocl~a for rhlor;n~t;^n traditionally ~elect ores and c, ~ ~ ~.trR which will re~ult in bonaf;riAtr~l ~roduct~ with low levels of silica. This is gQnr~rAlly achieved by mineral d~ ;n~J tachn;~ ~e baaed on 30 phyaical e _~rAt;~n~'. In these ~L-~28~oF it i8 only r~e~-ihl~ to reject ae~ao~nt;J~lly the majority of free quartz I~Articleg without gacrificinl7 L~ y of the valuable titania minerals. ~ level of rn;narAlo~ir~ ly antrp~na~
~ilica will normally remain in titaniferoua c^nrantrAt~R.
~wo 95l28502 2 1 8 7 8 9 2 pC'r/Ai In the ~ g ~A;n9 pL~ " for ilmenite to _Ynthotic rutile - which ~re presently operrte~l, the removal of iron and other major im~?urities result in a cnn~-~nt At;nn effect for the silic~ which ~TAn~rh~t~R the requirement_ for ;l te cnn- --ntr~t~R a_ feed_tock_ to ~rg ~A;n~ ~lant_. Silica i8 not removed by ny commerci~ rgrAAIng proce__.
rh~.m;cnl remov~l of _ilica from t;tnn;ferouR
cnn~ ~ntr~t~R and ~ d ~~t~r~l s can be achieved theoretically by aqueoug ~n~h;ng under J~ l ;no ~nnA;tinna. However, when 8uch len~h;ng i3 attempted under rr~ ticn~ conditions it has been found that the effectivenes_ of the le~ch is reduced by form3 of _ilica in the material which are not ~ hl~ to Alt~rnt;nn, i.e. are inert to leachin~, or by ren-tinnn between _ilica which ha3 entered ~cl~;nn and other ~ _ R of the titaniferou-m terial which result in the l?r~c;rit~t;nn of Rolid _;1 C~o-R material. Thi8 pr~;rit~t;on thuR limita the effectiveneRs of the leach in removing silica.
~hu8, in the l?rior art, _ilica and other impuritie_ have been removed from tit~niferouR material3 by aqueou_ le~h~nsr with very high e,.-~3n~ of _imple cau_tic _~lvtil~ns, An eXCegg i3 n~c~8~ry to ~revent impurities pre8ent within the t;tnn;ferous materiala (e.g. alumina) from interferin51 with the effectiveness of the leach. In some cases, the spent l~A~hJ~ntR, cnn~A;n;ng ---~-~n8~n of unused reagent ~re directly AiR~rA~d~ Recycle of learh~nt ~imply has the effect of c~ t~ng <leleterious impurities in the l~nr-h~nt and reducing the effectiveness of the leach. The cost of the caustic l e^~hAnl in such cases is l?rohibitive, ~ ;nlly when n~ rAl;~ stinn cost3 incurred for the purpose of liquor discard into the environment are cnnRi~ red.
There is no prior art in eYistence or cnnt~ t~A in which removal of 8ilica in a leach WO 95/28502 21 8 7 ~ 9 2 PCT/AU95/00222 c~n~ f~l in the ~ ~- - of ~cid il3 ;n~;~Af~cl to be ~ffective for the t . of titaniferous materials.
In sum~ry there i8 ~L~'F ' ly no industrially realistic ~rocess for the effective removal of silica from 5 titan~ ferous materials .
~ -cor~l~n~ly, the ~resent invention ~rovides an indu~trially realistic proce~ for llr~JrJ~;n~ of titaniferous materials, which ~rocess comprise~: the following ste~
(i) a l?retreatment which haa the effect of ron~Ar~n~ silica hl~ to le~rh;n~ under the ~articular conditions of a ~ubsequent leach, and ~ ii) an aqueous leach in the pL~ of an acid, the conditions of which are chosen such that silica whic~ enters so1~t; nn is t hydrolysed or preci~itated ~8 a ~; 1 ; c~te .
It is ~LeLeLl_~ that ~>retreatment ste~ (i) 20 ;nrl~ an aqueous c~ustic f~~
It has been surprisingly discovered that the ~rocess of the invention can remove ~ilica, alumina and other im~urities.
The tL~ ~ in ster (i) may include any 25 treatment which has the effect of ensurin~ th t the form of the silica in the f;t-n; r~ous ---t~ l enterinS~ ste~? (ii) is I hle to altAr~ti~n under the c~nA;fi~n~ of step (ii). For example, the treatment may include ~f;n~ of the tit~miferou~ m~terial to make a titaniferous slag. It 30 may lnclude roasting of ~he f I fnn~f~rous ---t~r;Al with additives which h ve the effect in roasting of converting ~Wo 9SI28502 P~T/AU95100222 c~nnt~;n~A silica to ~ At--~ or transferring ailica into a glaasy ~hase . The treatment may also be an ~ 1 kA 1 i n~ leach ~_ ~ , with or without other additive_, which has the effect of converting silica to ~ J~h~ or crystalline 5 ~;l;c-At~a. The LL~ may be a ~ 'nAt;r~n of these L,. s or of these tr~t ~ and other tr~A a which in r ' n~t;on have the de_ired effect.
Step ( i ) may be conducted in any suitable eq~ , which equipment will de~end in part on the 10 method chosen to ~erform thi8 8tep-8te~ ( ii ) i_ a leach conducted in the ~resence of~cid. Any ~uitable acid may be used, ;n~lvA;nSr hydrochloric and _ul~huric acids, but also ;n~ A;ng weak acid~ such as organic acid_ and sul~hurou_ acid. However, the leach _te~>
15 must be c~nA~ teA in such a manner that ~r~ itat; o~ of silica to a solid ~reci~itate or gel is avoided. The _t effective means of ensuring that hydroly_is is avoided is by cr~nf~ t;na the leach at low solids densities, thereby limiting the level of silica in the 8~ t;~n The leach may be ~nA~ t~d in any suitable A---- n~ ' . Tylpically it will be r ~nA~ teA in stirred t~mk reactors. T,~Arhing may be cnnf1~t~i in lt;rl-~ gtage8 or in a single stage, c~nt;n~usly or in batches. Solids and liquids flows through l~A-h;nSI may be cocurrent or 25 counte .i~-_L. ~Aa~nta may be added atAg~wi~e to r^-;ntA;n reagent strength throu5~h the leach or may be added in a _ingle stage .
Solid/liquid E _ rAt;~'n may be C~nA~ t~d after l~Ach;na in any suitable manner, ;nt~l~A;n5~ cycloning,
o 95128502 ~ 3 ~ PCT/~Ug5/00222 t~l Chlnrin~tinn cnn(1~nc~tion Purification Input Fe, Mn Consumes Solid/liquid nhl nri ne, chlorides coke, f oul increases ~ h, gas volumes make sludges Alkal i Def luidis e &alkali earth f luid beds du~
metals to liquid chlorides, consu,m. e chlorine, coke Al Consumes Causes Causes chlorine, corrosion corrosion, coke makes sludges Si A~ t~c Can encourage May require in duct dist; l l At; nr~
chlorinator, blockage. from product reducing Condenses in campaign part with life. titanium Consumes tetrachloride coke, chlorine V ~ust be removed by .-h ~m; CA 1 treatment and distillation Th, Ra A~ st~C
in chlorinator brichwork, radioactive;
- causes Ai cp-~c;ll di~ficulties W0 9S/28S02 2 1 8 7 8 9 ~ pcrlAu9sloo222 In the l?rior ~Art 3ynthetic rutile ha3 been formed from l ~tAn;fe~ro~n m;n_rAlA, e.g. ;l ;te, via v~riou..
techni~ue3. ~A~Anr~l;ng to the moat commAonly a~lied techni"ue, a3 variou31y or-Arnt~d in We3tern ~u3tralia, the 5 titani~erou3 mineral i3 reauced wlth coal or char in a rotary kiln, at t~ _ R in exces3 of 1100C. In thi3 ?roce33 the iron content of the mineral i.. Aubatnn~;Ally Al l; -- J . Sul~>hur addition3 are al30 made to convert r n ~ impurit ie3 pAArt ially to ~ 1 rh; r . Fo 1 lowing 10 re~ At;nn the ~ roduct i3 cooled, 3~rA AAt~d from A _ Q~; A t ~d ch~r, and then . ub j ected to a~ueou3 ; _ or removal of virtually nll ~AnntA;n~d All;~A iron a3 ~a rAhle fine iron oxide. ~rhe titaniAferou,, ~roduct of t;nn ia treated with 2-5% a~ueou,, 3ul~huric acid for 15 "~; _pA~ f; nn oAf _ -8 and 30me reeidual iron. There i3 no sub3tantial 1 removal of A lkal i or A 1 1rA l; n ~
earth3, Al n; ailicon, vanadium or rAA;nn-lAl;ArA, in this ~roce. a na A;-A-lceed or or-ArAted. Further, iron ~nd ne~e removal ia ;- _ lete.
~ecent A;AA,1. .. E~ have ~rovided a ~roce3a which A~re~A~t~ reA--A~;nn at lower t _ ~ .a and ~rovide3 for hydrochloric Acid l~Ah~n~ ~fter the a~ueous AorAt;nn 2md iron oxide 83~-- t;nn ste~a. ~-~AA,rA;nU to A;~103~rea the rroce33 i3 ef ~ective in removing iron, _ - - e, alkali 25 and All~Al;n~ earth i_;purities, a ,A.~hAtAnt;Al ~ro~ortion of Alllm;n; inrut3 ~nd 80A vanadiumA A3 well a3 thorium. The proce33 may be o~AAAAAt~d as a retrofit on ~ ;ng kiln ba3ed ;nRtAll~t;nn~. However, the ~rocess i3 ineffective in full vanadium removal and has little A1- '~AA1 i_pAct on 30 3ilicon.
In another ~rior art invention relatively hi,,h de~,ree3 of removal of ~,~n~Aillm _ --B, iron and ;n;llm have been achieved. In one such ~rocA3s ;1- ;te i3 AfirAt t-h~rr-lly reduced to suhstAnt;Ally ~ _lete 35 reA~At;nn of it3 ferric oxide content (i.e. without -~w09s~l8so2 ~ 1 ~3 78 92 PCr~Aug5~00222 s-lhat~nt;Al -~ll;Pat;nn), normally in a rotary lciln. The cooled, reduced product is then leached under 35 p~ai yreaaure at 140-150C with excess ?o% hydrochloric acid for removal of iron, ~ m~ m;n;~m and r~ e. The 5 leach liquor~ are apray roagted for ,. ~ t;nn of Lyd~ ~ chloride, which i~ recirculated to the lPArh;ng step .
In other l?Loc~nc~ the ilmenite u~Se~,es grain r~f;- by thermal nY;~t;nn followed hy thermal 10 reA--. t;nn (either in a f7.-;A;AeA bed or a rotary kiln) . The cooled, reduced product is then subjected to r _~ ic l~A~h;ng with exces~ 20% hydrochloric acid, for removal of the deleteriou~ impurities . Acid ~ t; nn i~3 also p~-f~ 7 by ~pray roa~ting in thi~ proce~s.
In all of the above ;nnod hydrochloric acid h;ng baAed ~ ~cea~A impurity removal is similar.
Vanadium, Al~m;n;~m and silicon removal is not fully e_fective .
In yet another procesg ilmenite i~ th~^l ly ao reduced (without Al1;Pot;nn) with carbon in a rotary kiln, ~ollowed by cooling in a nnnnY;A; s~inq ~.h~r6:. The cooled, reduced ~roduct iB leached under 20-30 p8i ~auge pres~ure at 130C with 10-60% (typically 18-25%) ~3ul~huric acid, in the 3?` ~ Q of a #eed material which assists 25 hydrolysi~ of di~solved titania, and cnn~ n~ly as~i~ts l~A~h~ng Of impuritie~. ~ydrochloric acid u~age in pl~ce o~
aUlphuriC acid has been claimed for this z~rocess. Under such circum~tance8 5imilar impurity removal to that ~chieved with other hydrochloric acid based systema is to 30 be ~ect-~A. Where sulphuric acid is uaed rAtl;oA~t;vity removal will not be - _ lete.
A commonly adopted method for upgrading of ilmenite to higher grade products is to smelt ilmenite with Wo 95128502 PCrlAUgS100222 coke ~ddition in ~n electric furnace, ~roducing a molten titan$ferous sla~ (for c~sting and crushin5~) and a ~i~J iron ~roduct. Of the ~roblem im~uritie_ only iron iQ removed in this manner, and then only incomrletely as a reQult of 5 compositional limitation8 of the ~rocess.
A wide rans~e of ~ot~Ant~Al feed_tocks i8 available for -rgrA~;n~ to high titania content materials suited to rhlar;n~ti~n . ~ _ lr~ of ~rim~ry titania sources which cannot be E~t~QfArt^rily ~rgrnded by ~rior art l?`C-~88~-10 for the u~ ~^~ of pro~ rt ion of a material suited to rhl^r;nl~ti^n include hard rock ~non detrital) ;l- ;taQ, R;l~reo~R ~ - rR, m ny ~rimary ( - -~hared) ;1- ;tAR
and large anatase resource_ . ~any such R e ~ ry gources (e.g. titania bearinsr slags) also exist.
Clearly there is a r~nR~ rAh~e incentive to discover methods for ll~srrA~inlJ of tit_niferous ~^-tar;AlQ
which can e: cAlly ~roduce high grade ~roduct3 alst irres~ectively of the nature of the im~urities in the feea.
At ~resent ~rc,ll~ce ~ of titania ~igment by the 20 choride ~roce3s require feed_tocks to havs silica levels as low as ~ossible. In general st fes~qQtocL-Q are less than 2% sio~. Where, for various reasons, feedstocks with high levele. of _ilica may be taken in, they are blended against other low _ilioa feedstoclcs, often with significant c08t 25 md ~roductivity prn~lt;~R. Therefore sll~l?l;ara of titaniferous feoARtocl~a for rhlor;n~t;^n traditionally ~elect ores and c, ~ ~ ~.trR which will re~ult in bonaf;riAtr~l ~roduct~ with low levels of silica. This is gQnr~rAlly achieved by mineral d~ ;n~J tachn;~ ~e baaed on 30 phyaical e _~rAt;~n~'. In these ~L-~28~oF it i8 only r~e~-ihl~ to reject ae~ao~nt;J~lly the majority of free quartz I~Articleg without gacrificinl7 L~ y of the valuable titania minerals. ~ level of rn;narAlo~ir~ ly antrp~na~
~ilica will normally remain in titaniferoua c^nrantrAt~R.
~wo 95l28502 2 1 8 7 8 9 2 pC'r/Ai In the ~ g ~A;n9 pL~ " for ilmenite to _Ynthotic rutile - which ~re presently operrte~l, the removal of iron and other major im~?urities result in a cnn~-~nt At;nn effect for the silic~ which ~TAn~rh~t~R the requirement_ for ;l te cnn- --ntr~t~R a_ feed_tock_ to ~rg ~A;n~ ~lant_. Silica i8 not removed by ny commerci~ rgrAAIng proce__.
rh~.m;cnl remov~l of _ilica from t;tnn;ferouR
cnn~ ~ntr~t~R and ~ d ~~t~r~l s can be achieved theoretically by aqueoug ~n~h;ng under J~ l ;no ~nnA;tinna. However, when 8uch len~h;ng i3 attempted under rr~ ticn~ conditions it has been found that the effectivenes_ of the le~ch is reduced by form3 of _ilica in the material which are not ~ hl~ to Alt~rnt;nn, i.e. are inert to leachin~, or by ren-tinnn between _ilica which ha3 entered ~cl~;nn and other ~ _ R of the titaniferou-m terial which result in the l?r~c;rit~t;nn of Rolid _;1 C~o-R material. Thi8 pr~;rit~t;on thuR limita the effectiveneRs of the leach in removing silica.
~hu8, in the l?rior art, _ilica and other impuritie_ have been removed from tit~niferouR material3 by aqueou_ le~h~nsr with very high e,.-~3n~ of _imple cau_tic _~lvtil~ns, An eXCegg i3 n~c~8~ry to ~revent impurities pre8ent within the t;tnn;ferous materiala (e.g. alumina) from interferin51 with the effectiveness of the leach. In some cases, the spent l~A~hJ~ntR, cnn~A;n;ng ---~-~n8~n of unused reagent ~re directly AiR~rA~d~ Recycle of learh~nt ~imply has the effect of c~ t~ng <leleterious impurities in the l~nr-h~nt and reducing the effectiveness of the leach. The cost of the caustic l e^~hAnl in such cases is l?rohibitive, ~ ;nlly when n~ rAl;~ stinn cost3 incurred for the purpose of liquor discard into the environment are cnnRi~ red.
There is no prior art in eYistence or cnnt~ t~A in which removal of 8ilica in a leach WO 95/28502 21 8 7 ~ 9 2 PCT/AU95/00222 c~n~ f~l in the ~ ~- - of ~cid il3 ;n~;~Af~cl to be ~ffective for the t . of titaniferous materials.
In sum~ry there i8 ~L~'F ' ly no industrially realistic ~rocess for the effective removal of silica from 5 titan~ ferous materials .
~ -cor~l~n~ly, the ~resent invention ~rovides an indu~trially realistic proce~ for llr~JrJ~;n~ of titaniferous materials, which ~rocess comprise~: the following ste~
(i) a l?retreatment which haa the effect of ron~Ar~n~ silica hl~ to le~rh;n~ under the ~articular conditions of a ~ubsequent leach, and ~ ii) an aqueous leach in the pL~ of an acid, the conditions of which are chosen such that silica whic~ enters so1~t; nn is t hydrolysed or preci~itated ~8 a ~; 1 ; c~te .
It is ~LeLeLl_~ that ~>retreatment ste~ (i) 20 ;nrl~ an aqueous c~ustic f~~
It has been surprisingly discovered that the ~rocess of the invention can remove ~ilica, alumina and other im~urities.
The tL~ ~ in ster (i) may include any 25 treatment which has the effect of ensurin~ th t the form of the silica in the f;t-n; r~ous ---t~ l enterinS~ ste~? (ii) is I hle to altAr~ti~n under the c~nA;fi~n~ of step (ii). For example, the treatment may include ~f;n~ of the tit~miferou~ m~terial to make a titaniferous slag. It 30 may lnclude roasting of ~he f I fnn~f~rous ---t~r;Al with additives which h ve the effect in roasting of converting ~Wo 9SI28502 P~T/AU95100222 c~nnt~;n~A silica to ~ At--~ or transferring ailica into a glaasy ~hase . The treatment may also be an ~ 1 kA 1 i n~ leach ~_ ~ , with or without other additive_, which has the effect of converting silica to ~ J~h~ or crystalline 5 ~;l;c-At~a. The LL~ may be a ~ 'nAt;r~n of these L,. s or of these tr~t ~ and other tr~A a which in r ' n~t;on have the de_ired effect.
Step ( i ) may be conducted in any suitable eq~ , which equipment will de~end in part on the 10 method chosen to ~erform thi8 8tep-8te~ ( ii ) i_ a leach conducted in the ~resence of~cid. Any ~uitable acid may be used, ;n~lvA;nSr hydrochloric and _ul~huric acids, but also ;n~ A;ng weak acid~ such as organic acid_ and sul~hurou_ acid. However, the leach _te~>
15 must be c~nA~ teA in such a manner that ~r~ itat; o~ of silica to a solid ~reci~itate or gel is avoided. The _t effective means of ensuring that hydroly_is is avoided is by cr~nf~ t;na the leach at low solids densities, thereby limiting the level of silica in the 8~ t;~n The leach may be ~nA~ t~d in any suitable A---- n~ ' . Tylpically it will be r ~nA~ teA in stirred t~mk reactors. T,~Arhing may be cnnf1~t~i in lt;rl-~ gtage8 or in a single stage, c~nt;n~usly or in batches. Solids and liquids flows through l~A-h;nSI may be cocurrent or 25 counte .i~-_L. ~Aa~nta may be added atAg~wi~e to r^-;ntA;n reagent strength throu5~h the leach or may be added in a _ingle stage .
Solid/liquid E _ rAt;~'n may be C~nA~ t~d after l~Ach;na in any suitable manner, ;nt~l~A;n5~ cycloning,
3 0 th; ~ n; nS;r~ f; l trat; ~n pressure f; l tr~t; ~n and o~ntr;f~ At;r~n The s~ent leachant may be cycled through leA~`hAnt treatment for the removal of iml?urities and back into the leach. Alternatively, s~ent 1~A~ hAnt may be WO 95/28502 ~ 1 ~ 7 8 9 2 pCT/A J9!
A;~ l or ~?roceed to be used in other proceas stages.
J~lA;t;r~nl1 steps may be inco-~o-~Led into the ~rocess as desired. For example:
(i) The leach residue may ~Agg to further ~rocessing, e.g. hot acid leArh;ng for the re~oval of impurities such as iron, magnes ium and ~ e .
(ii) The leach residue may be wa~hed.
(iii) The leach residue may be driea and/or cAl~-in~d and/or aggl~ t c'l.
(iv) Where 1~A-hnn1- is recycled a bleed stream may be removed in order to limit the c -~ n of ~articular lmpuritie~ .
(v) A ~rol?ortion o~ the wash liquors may be recycled as water make up.
(vi) The process may be p~-Jeded by "rS~r~1;nST
of the titaniferous material for the removal of i~puritie~ such as iron, ~ ai and _ a~, and ~?artial removal of Bilica ~nd alumin~.
(vii) S~ent ~A~ n~ and wash streams, whether or not treated for silica removal, may report to leach/ acid rQ~_norA~ n circuit3 wherein any r-l;o~ctive el ~ ~ removed in l~ h; nSr are de~orted to a suitable l~olid residue.
Clearly there is great f 1~ ; h; 1; ty within the - 21 ~7892 o95l28502 - 11 - pcrlAussloo222 proce3~- a~ A;~clo~d to a~~ ' te a wide range o~ _eed materials, aff well as pretreatment, leach and eoll~t;~n treatment c~n~;~;nna and ~ he process ~tel?s herein may be inco "~ ted in any ~--;tnhle =er into any other proce~s operated for the purpose of the ~-A;ng of titaniferous materi~
l~n ~le 1:
This example illustrate~ a multi stage I?retl~ - fgl 1 l ~ by a leach in the ~ .,_ ce of acid which has the effect of silica remoYal.
A titaniferou~ c~n~on~ ~te was ground, mixed and ~ggl ted with the AAA;~;on of 0.65% anydrou~ borax and 0.65% soda, ~dded a~ sodium cn~h~n~to, nd roasted with char at 1000C. The - _-eit;on of the roasted product ~fter char ~nrn~ n i~ giYen in Table 1. The roasting wa~
cnn~ rteA to enhance the -h;l;ty of silica in the feed to sub~equent lon~-h;n5r by fo~~t;r-n of a glassy pha~e.
The roa~ted material was subjected to le~-h;ng with boiling 45 g~?I. NaOH in the ~ _CC of 45 ~L Na2B407, 1.8 gpI, sio~ and 0.66 gpL Al20, under re~lux at 5% solid~
~lensity ~or 4 hours. The le~ch re~idue (after solid/liquid ~ern~At;nn and washing) c~nfn;nod 2.53% sio2 nd 1.04%
Al20~. That is, silica and alumina removal was ineffective.
However, with the ~Y~-ort; ~m of inert ~ilica and alumina the ~orm of alumina and silica in the residue had been converted to ~ m;n~ t~ of the fol~ thnid type.
The leach re~idue was then ~uhjected to room t~ (25C) le~ch;ng with 100 slpl. ~lrh~o~ acid at 10% solids density for 30 minutes. After solid/liquid ~ern~ n and washin5r the residue of thi8 leach l nn~:~;n~A
~ 87892 WO 95128502 Pcr/AUs5/00222 1.2% SiO~ and 0.3% Al~03. The preci~>itated Al~m;n~silicate was . _ 1 et~l y removed .
~le 2:
A sam~ple of a ~luart~ bearinl7 titania c~ t~
5 wa3 fully nY;~ with air at 900C and then reduced in a fl~l;A;--~, bed uging a hy~ /CO2 mixture such that the l~inal state of virtually all c~ntn;n~d iron was the 2l ; intir~n state. A 700g sample of this c~ n-e (who~e lit;On i8 recorded in Table 2) was then le~ched at 40wt% solids density for 4 hour~ at 175C in a ~ cl~;nn made u~ by adding 242 g/L of 40% sodium s;l;cnte 8c~ n (3.2:1 SiO2:Na20 weight basi~) and 15051/L of NaO!~.
A washed and dried aam~le of the leach residue had the co~osition which i~ also recorded in Table 2. The5 _ajority of the residual silica in this _aterial wa~ ~ a ium nl~m;nns;l;~te which has formea during the leach.
A 300g sample of the leach re~idue was leached llt 10% ~olids density for 1 hour at 25C in a Elol~ n of 5%
}~CL. After this cold acid le~ch a wa~hed and dried sam~le 20 of residue had the c- _-1it;~ln which i~ also recorded in Table 2.
Clearly the ~cid leach had been ef f ective f or the removal o~ silica de~o3ited as nl~ nte in the initial leach.
21 8789~
WO 951Z850Z PCTI~
-- 13 ~
3~sa~ple 3:
Pellets of a ground titania slag ~a product of ilmenite ~~t;nSr) having a co_position recorded in Table 3 were made u~ with addition of 1% Na2 B407 and ronsted at 1000C for two hours in a flow of 1:19 H2O/CO2 gas mixture, to oxidise trivalent titania.
~ ~am~le of the ~ellet3 was then subjected to l~ch;ng at 25wt% solids density with 20% H2~04 at 135C
for 6 hours. The analysis of the leach residue ~ .,L~ed in Table 3 shows that there was neS~ ible removal of silica in the acid leach.
A further sam~le of the ~ellets were ~ubjected to ~ rh nçr with boilin~ 100 snL NaOH for 6 hours at 10wt%
Elolid~ density at 165C. The ~ it;~n of the caustic lQach residue is ~ aco~ 1 in Table 4. Bven at low slurry ;~ silica is retained as Al~m;n~ il;eAte due to ~t~a~ n of the ~e~ hJ~nt with alumina.
The caustic leached re3idue was subjected to an acid leach with 20% HCL at 30% solids density for 6 hours at reflux. The --~ n of the residue of acid leachin~J
i~ L~col-led in Table 4. The - ' n~tion of the caustic leach treatment with the acid leach t~ ' had been highly effective in the removal of silica in the Acid leach .
WO 95/28502 Pcrl~U9S/00222 Table 1: C ~ ;nn of~ qlh~-~-lly p., ~F1-J Feed in Ex~le 1.
wt .%
Tio2 63 . 4 FeO 2 5 . 7 ~io2 3 . 81 Al2O3 o . 83 Na2O 0 . 88 ~gO 0.88 MnO 1. 10 other 2 . 0 Table 2: Con~ositions of Feed and Leach ~ in }Zxample 2.
Feed ~ n~ A~id LeAch Leal:h Re3idue Res idue Tio2 65.7 66.4 67.7 FeO26.5 26.9 26.4 15sio2 3 . 1 0 . 94 0 . 37 Al2O3 o . 8 0 . 67 0 . 49 Na2O n.d. 0.2 n.d.
~o 1.1 0.88 0.88 MnO1.1 1.2 1.2 20 CaO n.d. 0.03 0.01 othert 1. 4 2 . 8 2 . 9 ~N.B. ;n~lllA-~ water o~ hydra- ion.
~WO95/28S02 21 8 7 ~ 9 2 PCrlAU95100222 ~
Table 3: Compositions of Slag Feed and Acid Leach Re~idue in Rxa~4ple 3.
Feed Slag Acid Leached Slag Tio2 77 . 9 88 FeO 9.1 4.0 5sio2 2.8 3.1 Al2O3 3 .1 0 . 95 Na2O 0.08 0.05 ~gO 4.8 2.15 MnO 0.24 0.11 10CaO 0.47 0.17 Other 0 . 5 1. 5 Table 4: Com~ositionR of Cau~atic Leach and S~ t Acid Leach 17~3i~"913 in 13xam~le 3.
Caustic Leach Acid Leach Re~idue Residue Tio2 78.4 82.7 15FeO 9.1 7.7 SiO2 3.1 0.96 Al2O3 3.1 2.7 Na2O n.d. n.d.
MgO 4.8 4.8 20NnO 0.25 0.23 CaO 0.38 0.13 Other 0 . 9 0 . 8
A;~ l or ~?roceed to be used in other proceas stages.
J~lA;t;r~nl1 steps may be inco-~o-~Led into the ~rocess as desired. For example:
(i) The leach residue may ~Agg to further ~rocessing, e.g. hot acid leArh;ng for the re~oval of impurities such as iron, magnes ium and ~ e .
(ii) The leach residue may be wa~hed.
(iii) The leach residue may be driea and/or cAl~-in~d and/or aggl~ t c'l.
(iv) Where 1~A-hnn1- is recycled a bleed stream may be removed in order to limit the c -~ n of ~articular lmpuritie~ .
(v) A ~rol?ortion o~ the wash liquors may be recycled as water make up.
(vi) The process may be p~-Jeded by "rS~r~1;nST
of the titaniferous material for the removal of i~puritie~ such as iron, ~ ai and _ a~, and ~?artial removal of Bilica ~nd alumin~.
(vii) S~ent ~A~ n~ and wash streams, whether or not treated for silica removal, may report to leach/ acid rQ~_norA~ n circuit3 wherein any r-l;o~ctive el ~ ~ removed in l~ h; nSr are de~orted to a suitable l~olid residue.
Clearly there is great f 1~ ; h; 1; ty within the - 21 ~7892 o95l28502 - 11 - pcrlAussloo222 proce3~- a~ A;~clo~d to a~~ ' te a wide range o~ _eed materials, aff well as pretreatment, leach and eoll~t;~n treatment c~n~;~;nna and ~ he process ~tel?s herein may be inco "~ ted in any ~--;tnhle =er into any other proce~s operated for the purpose of the ~-A;ng of titaniferous materi~
l~n ~le 1:
This example illustrate~ a multi stage I?retl~ - fgl 1 l ~ by a leach in the ~ .,_ ce of acid which has the effect of silica remoYal.
A titaniferou~ c~n~on~ ~te was ground, mixed and ~ggl ted with the AAA;~;on of 0.65% anydrou~ borax and 0.65% soda, ~dded a~ sodium cn~h~n~to, nd roasted with char at 1000C. The - _-eit;on of the roasted product ~fter char ~nrn~ n i~ giYen in Table 1. The roasting wa~
cnn~ rteA to enhance the -h;l;ty of silica in the feed to sub~equent lon~-h;n5r by fo~~t;r-n of a glassy pha~e.
The roa~ted material was subjected to le~-h;ng with boiling 45 g~?I. NaOH in the ~ _CC of 45 ~L Na2B407, 1.8 gpI, sio~ and 0.66 gpL Al20, under re~lux at 5% solid~
~lensity ~or 4 hours. The le~ch re~idue (after solid/liquid ~ern~At;nn and washing) c~nfn;nod 2.53% sio2 nd 1.04%
Al20~. That is, silica and alumina removal was ineffective.
However, with the ~Y~-ort; ~m of inert ~ilica and alumina the ~orm of alumina and silica in the residue had been converted to ~ m;n~ t~ of the fol~ thnid type.
The leach re~idue was then ~uhjected to room t~ (25C) le~ch;ng with 100 slpl. ~lrh~o~ acid at 10% solids density for 30 minutes. After solid/liquid ~ern~ n and washin5r the residue of thi8 leach l nn~:~;n~A
~ 87892 WO 95128502 Pcr/AUs5/00222 1.2% SiO~ and 0.3% Al~03. The preci~>itated Al~m;n~silicate was . _ 1 et~l y removed .
~le 2:
A sam~ple of a ~luart~ bearinl7 titania c~ t~
5 wa3 fully nY;~ with air at 900C and then reduced in a fl~l;A;--~, bed uging a hy~ /CO2 mixture such that the l~inal state of virtually all c~ntn;n~d iron was the 2l ; intir~n state. A 700g sample of this c~ n-e (who~e lit;On i8 recorded in Table 2) was then le~ched at 40wt% solids density for 4 hour~ at 175C in a ~ cl~;nn made u~ by adding 242 g/L of 40% sodium s;l;cnte 8c~ n (3.2:1 SiO2:Na20 weight basi~) and 15051/L of NaO!~.
A washed and dried aam~le of the leach residue had the co~osition which i~ also recorded in Table 2. The5 _ajority of the residual silica in this _aterial wa~ ~ a ium nl~m;nns;l;~te which has formea during the leach.
A 300g sample of the leach re~idue was leached llt 10% ~olids density for 1 hour at 25C in a Elol~ n of 5%
}~CL. After this cold acid le~ch a wa~hed and dried sam~le 20 of residue had the c- _-1it;~ln which i~ also recorded in Table 2.
Clearly the ~cid leach had been ef f ective f or the removal o~ silica de~o3ited as nl~ nte in the initial leach.
21 8789~
WO 951Z850Z PCTI~
-- 13 ~
3~sa~ple 3:
Pellets of a ground titania slag ~a product of ilmenite ~~t;nSr) having a co_position recorded in Table 3 were made u~ with addition of 1% Na2 B407 and ronsted at 1000C for two hours in a flow of 1:19 H2O/CO2 gas mixture, to oxidise trivalent titania.
~ ~am~le of the ~ellet3 was then subjected to l~ch;ng at 25wt% solids density with 20% H2~04 at 135C
for 6 hours. The analysis of the leach residue ~ .,L~ed in Table 3 shows that there was neS~ ible removal of silica in the acid leach.
A further sam~le of the ~ellets were ~ubjected to ~ rh nçr with boilin~ 100 snL NaOH for 6 hours at 10wt%
Elolid~ density at 165C. The ~ it;~n of the caustic lQach residue is ~ aco~ 1 in Table 4. Bven at low slurry ;~ silica is retained as Al~m;n~ il;eAte due to ~t~a~ n of the ~e~ hJ~nt with alumina.
The caustic leached re3idue was subjected to an acid leach with 20% HCL at 30% solids density for 6 hours at reflux. The --~ n of the residue of acid leachin~J
i~ L~col-led in Table 4. The - ' n~tion of the caustic leach treatment with the acid leach t~ ' had been highly effective in the removal of silica in the Acid leach .
WO 95/28502 Pcrl~U9S/00222 Table 1: C ~ ;nn of~ qlh~-~-lly p., ~F1-J Feed in Ex~le 1.
wt .%
Tio2 63 . 4 FeO 2 5 . 7 ~io2 3 . 81 Al2O3 o . 83 Na2O 0 . 88 ~gO 0.88 MnO 1. 10 other 2 . 0 Table 2: Con~ositions of Feed and Leach ~ in }Zxample 2.
Feed ~ n~ A~id LeAch Leal:h Re3idue Res idue Tio2 65.7 66.4 67.7 FeO26.5 26.9 26.4 15sio2 3 . 1 0 . 94 0 . 37 Al2O3 o . 8 0 . 67 0 . 49 Na2O n.d. 0.2 n.d.
~o 1.1 0.88 0.88 MnO1.1 1.2 1.2 20 CaO n.d. 0.03 0.01 othert 1. 4 2 . 8 2 . 9 ~N.B. ;n~lllA-~ water o~ hydra- ion.
~WO95/28S02 21 8 7 ~ 9 2 PCrlAU95100222 ~
Table 3: Compositions of Slag Feed and Acid Leach Re~idue in Rxa~4ple 3.
Feed Slag Acid Leached Slag Tio2 77 . 9 88 FeO 9.1 4.0 5sio2 2.8 3.1 Al2O3 3 .1 0 . 95 Na2O 0.08 0.05 ~gO 4.8 2.15 MnO 0.24 0.11 10CaO 0.47 0.17 Other 0 . 5 1. 5 Table 4: Com~ositionR of Cau~atic Leach and S~ t Acid Leach 17~3i~"913 in 13xam~le 3.
Caustic Leach Acid Leach Re~idue Residue Tio2 78.4 82.7 15FeO 9.1 7.7 SiO2 3.1 0.96 Al2O3 3.1 2.7 Na2O n.d. n.d.
MgO 4.8 4.8 20NnO 0.25 0.23 CaO 0.38 0.13 Other 0 . 9 0 . 8
Claims (6)
1. An industrially realistic process for upgrading of titaniferous materials, which process comprises the following steps:
(i) a pretreatment which has the effect of rendering silica amenable to leaching under the particular conditions of a subsequent leach, and (ii) an aqueous leach in the presence of an acid, the conditions of which are chosen such that silica which enters solution is not hydrolysed or precipitated as a silicate.
(i) a pretreatment which has the effect of rendering silica amenable to leaching under the particular conditions of a subsequent leach, and (ii) an aqueous leach in the presence of an acid, the conditions of which are chosen such that silica which enters solution is not hydrolysed or precipitated as a silicate.
2. The process defined in claim 1 wherein the pretreatment step (i) comprises alkaline leaching the titaniferous material which has the effect of converting silica to amorphous or crystalline silicates.
3. The process defined in claim 1 or claim 2 wherein the pretreatment step (i) comprises roasting the titaniferous material, with or without an additive, which has the effect in roasting of converting contained silica to silicates or transferring silica into a glassy phase.
4. The process defined in claim 2 or claim 3 wherein the pretreatment step (i) comprises smelting the titaniferous material to make a titaniferous slag.
5. The process defined in any one of the preceding claims wherein the acid of the leach step (ii) comprises any one of hydrochloric acid, sulphuric acid, an organic acid, and sulphurous acid.
6. The process defined in any one of the preceding claims which comprises conducting the leached step (ii) at low solids densities.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPM5119A AUPM511994A0 (en) | 1994-04-15 | 1994-04-15 | Leaching of a titaniferous material |
| AUPM5119 | 1994-04-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2187892A1 true CA2187892A1 (en) | 1995-10-26 |
Family
ID=3779699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002187892A Abandoned CA2187892A1 (en) | 1994-04-15 | 1995-04-18 | Leaching of a titaniferous material |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0755459A1 (en) |
| JP (1) | JPH09512057A (en) |
| CN (1) | CN1148412A (en) |
| AU (1) | AUPM511994A0 (en) |
| BR (1) | BR9507395A (en) |
| CA (1) | CA2187892A1 (en) |
| IN (1) | IN182628B (en) |
| NO (1) | NO964351L (en) |
| WO (1) | WO1995028502A1 (en) |
| ZA (1) | ZA953046B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5997606A (en) * | 1997-08-11 | 1999-12-07 | Billiton Sa Limited | Production of titanium slag |
| US6713038B2 (en) | 2000-04-18 | 2004-03-30 | Millenium Inorganic Chemicals, Inc. | TiO2 compounds obtained from a high silica content ore |
| US7625536B2 (en) * | 2005-10-18 | 2009-12-01 | Millennium Inorganic Chemicals, Inc. | Titaniferous ore beneficiation |
| CN105543474B (en) * | 2015-12-21 | 2018-02-02 | 中南大学 | A kind of method of ilmenite transition refining and edulcoration |
| CN105967231A (en) * | 2016-06-22 | 2016-09-28 | 中国神华能源股份有限公司 | Method for extracting TiO2 from white clay |
| CA3054603A1 (en) * | 2017-03-02 | 2018-09-07 | Outotec (Finland) Oy | Method of treating titanium-containing slag |
| CN111646502B (en) * | 2020-06-10 | 2022-08-02 | 攀钢集团研究院有限公司 | Slag ore mixing continuous acidolysis leaching method and equipment |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2815272A (en) * | 1955-03-10 | 1957-12-03 | Nat Lead Co | Method of producing titanium concentrates |
| BR8701481A (en) * | 1986-04-03 | 1988-01-19 | Du Pont | PROCESS FOR PURIFICATION OF TIO2 ORE AND TIO2 PIGMENT OBTAINED BY THE PROCESS |
| US5011666A (en) * | 1988-07-28 | 1991-04-30 | E. I. Du Pont De Nemours And Company | Method for purifying TiO2 ore |
| AU4458993A (en) * | 1990-03-02 | 1993-11-11 | Wimmera Industrial Minerals Pty Ltd | Production of synthetic rutile |
| AU639178B2 (en) * | 1991-04-19 | 1993-07-15 | Rgc Mineral Sands Limited | Conversion of ilmenite to synthetic rutile e.g. by the becher process |
| AU639390B2 (en) * | 1991-04-19 | 1993-07-22 | Rgc Mineral Sands Limited | Removal of radionuclides from titaniferous material |
| RU2121009C1 (en) * | 1992-07-31 | 1998-10-27 | Ар-Джи-Си Минерал Сэндз Лимитед | Method of simplifying removal of radioisotopes and method of treating iron- and titanium-containing material |
| WO1994004709A1 (en) * | 1992-08-14 | 1994-03-03 | Technological Resources Pty. Limited | Upgrading titaniferous materials |
| US5730774A (en) * | 1993-05-07 | 1998-03-24 | Technological Resources Pty Ltd. | Process for upgrading titaniferous materials |
| CA2171185A1 (en) * | 1993-09-07 | 1995-03-16 | Ross Alexander Mcclelland | Upgrading titaniferous materials |
-
1994
- 1994-04-15 AU AUPM5119A patent/AUPM511994A0/en not_active Abandoned
-
1995
- 1995-04-13 ZA ZA953046A patent/ZA953046B/en unknown
- 1995-04-17 IN IN406CA1995 patent/IN182628B/en unknown
- 1995-04-18 CN CN95193046A patent/CN1148412A/en active Pending
- 1995-04-18 JP JP7526577A patent/JPH09512057A/en active Pending
- 1995-04-18 CA CA002187892A patent/CA2187892A1/en not_active Abandoned
- 1995-04-18 WO PCT/AU1995/000222 patent/WO1995028502A1/en not_active Application Discontinuation
- 1995-04-18 BR BR9507395-7A patent/BR9507395A/en not_active Application Discontinuation
- 1995-04-18 EP EP95915693A patent/EP0755459A1/en not_active Withdrawn
-
1996
- 1996-10-11 NO NO964351A patent/NO964351L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09512057A (en) | 1997-12-02 |
| NO964351D0 (en) | 1996-10-11 |
| EP0755459A1 (en) | 1997-01-29 |
| BR9507395A (en) | 1999-08-31 |
| IN182628B (en) | 1999-05-22 |
| EP0755459A4 (en) | 1997-02-26 |
| CN1148412A (en) | 1997-04-23 |
| NO964351L (en) | 1996-12-10 |
| ZA953046B (en) | 1996-01-15 |
| WO1995028502A1 (en) | 1995-10-26 |
| AUPM511994A0 (en) | 1994-05-12 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |