CA1103933A - Method of upgrading a titaniferous ore utilising reductive roasting - Google Patents
Method of upgrading a titaniferous ore utilising reductive roastingInfo
- Publication number
- CA1103933A CA1103933A CA287,207A CA287207A CA1103933A CA 1103933 A CA1103933 A CA 1103933A CA 287207 A CA287207 A CA 287207A CA 1103933 A CA1103933 A CA 1103933A
- Authority
- CA
- Canada
- Prior art keywords
- sulphur
- iron
- ore
- process according
- containing compound
- 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.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 27
- 230000002829 reductive effect Effects 0.000 title claims abstract description 21
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 65
- 229910052742 iron Inorganic materials 0.000 claims abstract description 31
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 claims abstract description 23
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000005864 Sulphur Substances 0.000 claims abstract description 21
- 150000001875 compounds Chemical class 0.000 claims abstract description 19
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 12
- 238000002386 leaching Methods 0.000 claims abstract description 8
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 24
- 239000011572 manganese Substances 0.000 claims description 20
- 229910052748 manganese Inorganic materials 0.000 claims description 16
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 15
- 230000009467 reduction Effects 0.000 claims description 14
- 239000011780 sodium chloride Substances 0.000 claims description 12
- 238000001465 metallisation Methods 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 8
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims description 6
- 239000003638 chemical reducing agent Substances 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 4
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 3
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 3
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 3
- 239000011707 mineral Substances 0.000 claims description 3
- 229910052938 sodium sulfate Inorganic materials 0.000 claims description 3
- 235000011152 sodium sulphate Nutrition 0.000 claims description 3
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 3
- 239000005569 Iron sulphate Substances 0.000 claims description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 2
- 239000001166 ammonium sulphate Substances 0.000 claims description 2
- 239000012736 aqueous medium Substances 0.000 claims description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- WBHQBSYUUJJSRZ-UHFFFAOYSA-M sodium bisulfate Chemical compound [Na+].OS([O-])(=O)=O WBHQBSYUUJJSRZ-UHFFFAOYSA-M 0.000 claims description 2
- 229910009815 Ti3O5 Inorganic materials 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 229910000342 sodium bisulfate Inorganic materials 0.000 claims 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 abstract description 4
- 239000000460 chlorine Substances 0.000 abstract description 4
- 229910052801 chlorine Inorganic materials 0.000 abstract description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 abstract description 3
- 235000013980 iron oxide Nutrition 0.000 abstract description 3
- 229960005191 ferric oxide Drugs 0.000 abstract 1
- 235000002908 manganese Nutrition 0.000 description 15
- 239000012071 phase Substances 0.000 description 10
- 239000000047 product Substances 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 239000007787 solid Substances 0.000 description 4
- 239000003245 coal Substances 0.000 description 3
- 238000010348 incorporation Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 229910005451 FeTiO3 Inorganic materials 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 150000003841 chloride salts Chemical class 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000010587 phase diagram Methods 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000008246 gaseous mixture Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000007885 magnetic separation Methods 0.000 description 1
- 150000002696 manganese Chemical class 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- -1 natural gas Chemical class 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 230000003019 stabilising effect Effects 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
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
- C22B34/1204—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
-
- 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
-
- 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
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
ABSTRACT
An improved method of upgrading titaniferous ores, especially ilmenite, utilising reductive roasting. The ore is reduced in the presence of a chlorine-containing compound and sulphur or a sulphur-containing compound to produce metallic iron and titanium dioxide and the iron is subsequently removed by leaching.
An improved method of upgrading titaniferous ores, especially ilmenite, utilising reductive roasting. The ore is reduced in the presence of a chlorine-containing compound and sulphur or a sulphur-containing compound to produce metallic iron and titanium dioxide and the iron is subsequently removed by leaching.
Description
~3~3 This invention rela-tes -to an improved method of upgrading titaniferous ores , especially ilmenite, utilising reductive roasting.
There are a number of methods well described in the literature for the upgrading of ilmenite by the removal of iron to produce a product containing in excess of 90%
TiO2. Ilmenite is a naturally occurring mineral of the hypothetical formula FeTiO3. Most ilmenit~s however contain a considerable amount of other elements and consequently the theoretical titanlum dioxide and iron contents are rarely present. Common impurities are manganese and magnesium, which elements form solid solution series with iron-rich ilmenite and may even form magnesium or manganese end members of this solid solution series~
1,5 One such method of upgrading ilmenite is that in which the iron oxides in the ilmenite are reduced either by carbon gaseous mixtures or solid reductants to the metalllc state, and the metallic iron so formed removed either physically or preferably by some leach process to leave a / 20 TlO2-enriched residual product. Such processes are well described in the literature.
It has been found in practice that the degree of ' metallisation,that can be achieved when reducing ilmenite .
is limited. The degree of metallisation is a measure of
There are a number of methods well described in the literature for the upgrading of ilmenite by the removal of iron to produce a product containing in excess of 90%
TiO2. Ilmenite is a naturally occurring mineral of the hypothetical formula FeTiO3. Most ilmenit~s however contain a considerable amount of other elements and consequently the theoretical titanlum dioxide and iron contents are rarely present. Common impurities are manganese and magnesium, which elements form solid solution series with iron-rich ilmenite and may even form magnesium or manganese end members of this solid solution series~
1,5 One such method of upgrading ilmenite is that in which the iron oxides in the ilmenite are reduced either by carbon gaseous mixtures or solid reductants to the metalllc state, and the metallic iron so formed removed either physically or preferably by some leach process to leave a / 20 TlO2-enriched residual product. Such processes are well described in the literature.
It has been found in practice that the degree of ' metallisation,that can be achieved when reducing ilmenite .
is limited. The degree of metallisation is a measure of
2'5 the amount of to*al iron originally present as iron oxides in the ilmenite that can be reduced to the metallic state.
The thermodynqmicsof the reduction of ilmenite have been - studied using mainly synthetic ilmenite. In general the .~ , .
thermodynamics a,re unfavourable compared with normal iron ores not containing titanium. While this fact can account " ~ ' ' '2 .
, .
g~3 in part for the limited degree of metallisation achieved, in practice it is not the entire reason for these limitations. ~~
In fluid bed or kiln reductions, oxygen partial pressures at a level of 10 16 or 10 l7mm. Hg can be obtained and it would normally be expected that at these levels a very high degree of metallisation would be achieved. However levels in excess of 95 or 96go are not normally obtained.
Due to the formation of Ti3~ during-~eduction it has been found that, when this Ti3+ is incorporated into - 10 the phases of the Fe-TixOy system, extended regions of stoichiometry result as observed in the phase diagram of McChesney and Muan. As a result of this, at low oxygen partial pressures of approximately 10 mm. Hg, alternate two and three solid phase reduced rutile plus iron assemblages are stable, thus reduction of pure ilmenite should result in a mixture of reduced rutiles and metallic iron only. The -degree of metallisation is then a function only of the incorporation of-Fe2+ into the reduced rutile phase, and very high degrees of metallisation would be expected.
However, these are not obtained in practice. Most natural ilmenites contain 0.5 to 1.5% by weight of manganese oxide, ~ ~ .
usually as a solid solution oE MnTiO3 in FeTiO3, and this manganese has a very adverse effect on the degree of iron metallisation that can be achieved. In reduction of natural Mn-containing ilmenites, the Mn and residual Fe will concentrate in a Ti305-rich anosovite phase. No practical gaseous reduction procedure will produce Mn metal. Due to the phase equilibria that then exist, and this formation of a M305 (solid solution) stable phase containing iron and stabilised by manganese, the amount of iron that can be _ 3 _ . . .
. ' .
' . .... . . - ' , .
: ., , ' . ., - ~
1 ~ 3~ 3 3 reduced is consequently limited.
The phases thus formed are extremely stable, and even leaching in strong acids will not remove the iron and manganese remaining after all metallic iron has been removed.
Thus the composition of the final upgraded product is limited by these impurities.
This invention has as its main object the provision of modifications in the above-described process which allow substantial proportions of this residual iron and manganese to be solubilised so that they can be removed either by wash-ing with dilute acid or even water.
We have found that by the incorporation of a small amount of chlorine-containing compound, together with sulphur or a sulphur-containing compound, at the reduction stage, most of the residual non-metallic iron can be solubilised as well as a proportion of the manganese.
According to the present invention, there is provided a process for the beneficiation of a titaniferous iron ore containlng manganese impurities which process com~rises forming a mixture consisting essentially of the ore and sodium chloride and sulphuror a sulphu~containing compound. The mixture is ~'~ heated at a temperature within the range o~ 1000C to 1250C
in the presence of a reducing agent to provide a reduced ore rich in titanium dioxide in which metallic iron has been solubilised.
The reduced ore is leached to extract the iron therefrom, the ,. ~
;~ ~ sodium chloride and the sul~hur or sulphur-containing compound being added in amounts effective to inhibit the production of , an unleachable Ti3Q5 anosovite phase during the reduction stage and thereby increase the degree of metallization, but in amounts such that the proportion of the sodium chloride together with the sulphur or sulphur-containing compound is in the range of from ~.1% to 10% by weight of the ore.
. . : , ~3g33 As indicated above, the process of the invention is especially concerned with the beneficiation of ilmenite.
The preferred chlorine-containing compounds are metallic chlorides, most preferably sodium chloride. The preferred quantities of sodium chloride added at the reduction stage generally range from 0.1~ to 10% by weight of the ore, but can be as high as 20%. Other chlorides may be used in equiva-lent quantities.
The sulphur-containing compound may be a solid or a gaseous compound. The latter may be SO2 while the preferred solid compounds are metallic or ammonium sulphates, such as sodium sulphate, sodium bisulphate, ammonium sulphate, most preferably iron sulphate. These may be added in quantities of 0.1% - 10~ by weight of the ore.
The weight ratio of the sulphur or sulphur-containing compound to the chlorine-containing compound can be widely varied but it is preferably in the range 1:20 to 20:1.
The preferred reduction temperature and time are in the ranges 1000C to 1250C, and 1/2 to 16 hours respectively.
Any suitable reductant known per se in the art may be used; for example, reducing gases such as hydrogen, carbon monoxide or hydrocarbons, including natural gas, producer or water gas and refor~ed naphtha; liquid hydrocarbons, such as , ~ , fuel oll; or solid reductants such as coke or coal; and mix-tures of any such reductants.
Leaching of the reduced product can also be carried out with any suitable leachant known per se in the art. The most preferred technique is to remove the metallic iron by accelerated rusting in an aqueous medium. Alternatively or ; 30 additionally acid leaching may be used, this being especially useful where significant amounts of manganese are to be removed.
The process of the invention can be applied to previously ^ '' ' .
upyraded ores, such as an upgraded ilmenite containing say in excess of 85% TiO2 to reduce the residual iron and manganese impurit,ies, or it can be applied to the as-mined or dressed ore. All such materials are to be considered as falling within the scope of the term "ore" as used herein. The invention is applicable to the treatment of such ores by either batch or continuous reductive roasting processes.
As thus applied, the process of the invention overcomes, at least in part, the adverse effects of the presence of small amounts of manganese and residual Fe2+ in stabilising the M305 solid solution phase by reducing the amount of manganese available for incorporation into the M305 phase. The amount of iron incorporated into the M305 phase is decreased and the amount of iron that can be reduced to the metallic state is consequently increased.
The invention will now be further descri~ed with refer-ence to the following non-limitative examples.
; EXAMPLE 1 :
A reduction kiln 2.4m in diameter by 30m in length was fed with hot pre-oxidised ilmenite and maintained at a temperature of 1150C to 1200C, by the use of coal. The !~ ` oxidised ilmenite was fed to this kiln at the rate of 2.2 - 2.6 tph and the sodium chloride and sulphur added at the rate of 1.65 -2.0% by weight of the ilmenite and 0.6% by weight of the ilmenite, respectively. The product from the reduction kiln ' ~ was cooled and the reduced ilmenite separated from the residual ,~ char by means of screening and magnetic separation. The reduced ilmenite was then treated by an accelerated rusting process to remove metallic iron and then finally leached with , ~ 4~% sulphuric acld. The final product resulting form this treat-ment contained between 92.0 - 93.3% Tio2, a total iron content ~ B - 6 -' ' ":
of 2.2% and a manganese content of 1.1% expressed as MnO. Without the addition of the additives the material would normally contain approximately 4-5% total iron and 1.7-1.8~ Mn expressed as MnO.
EXA~PLE 2 Samples of oxidised ilmenite were reduced at 1150C
with Collie Coal char, and with the addition of varying amounts of a mixture of sodium chloride and sodium sulphate. After reduction the reduced ilmenite was leached with HCl `~
, j~ :
I
:,: :
' :`
. ~ .
`::
~ , .
., to remove metallic iron and then with 4% sulphuric acid to remove any solubilised manganese. The results are plotted graphically in the accompanying drawing. It will be noted that very substantial removal of the manga-nese has been achieved in these tests and tha-t the addition of sodium chloride has allowed manganese removal to take place at lower concentrations of sulphate.
Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described.
It is to be understood that the invention includes all such variations and modifications which fall within its spirit an~ scope~
The phase diagram of McChesney and Muan referred to above appears in Amer. Mineral, 46, 1961, 572-82.
' ~ ~ 25 '~ ' - , : 30 ' ,
The thermodynqmicsof the reduction of ilmenite have been - studied using mainly synthetic ilmenite. In general the .~ , .
thermodynamics a,re unfavourable compared with normal iron ores not containing titanium. While this fact can account " ~ ' ' '2 .
, .
g~3 in part for the limited degree of metallisation achieved, in practice it is not the entire reason for these limitations. ~~
In fluid bed or kiln reductions, oxygen partial pressures at a level of 10 16 or 10 l7mm. Hg can be obtained and it would normally be expected that at these levels a very high degree of metallisation would be achieved. However levels in excess of 95 or 96go are not normally obtained.
Due to the formation of Ti3~ during-~eduction it has been found that, when this Ti3+ is incorporated into - 10 the phases of the Fe-TixOy system, extended regions of stoichiometry result as observed in the phase diagram of McChesney and Muan. As a result of this, at low oxygen partial pressures of approximately 10 mm. Hg, alternate two and three solid phase reduced rutile plus iron assemblages are stable, thus reduction of pure ilmenite should result in a mixture of reduced rutiles and metallic iron only. The -degree of metallisation is then a function only of the incorporation of-Fe2+ into the reduced rutile phase, and very high degrees of metallisation would be expected.
However, these are not obtained in practice. Most natural ilmenites contain 0.5 to 1.5% by weight of manganese oxide, ~ ~ .
usually as a solid solution oE MnTiO3 in FeTiO3, and this manganese has a very adverse effect on the degree of iron metallisation that can be achieved. In reduction of natural Mn-containing ilmenites, the Mn and residual Fe will concentrate in a Ti305-rich anosovite phase. No practical gaseous reduction procedure will produce Mn metal. Due to the phase equilibria that then exist, and this formation of a M305 (solid solution) stable phase containing iron and stabilised by manganese, the amount of iron that can be _ 3 _ . . .
. ' .
' . .... . . - ' , .
: ., , ' . ., - ~
1 ~ 3~ 3 3 reduced is consequently limited.
The phases thus formed are extremely stable, and even leaching in strong acids will not remove the iron and manganese remaining after all metallic iron has been removed.
Thus the composition of the final upgraded product is limited by these impurities.
This invention has as its main object the provision of modifications in the above-described process which allow substantial proportions of this residual iron and manganese to be solubilised so that they can be removed either by wash-ing with dilute acid or even water.
We have found that by the incorporation of a small amount of chlorine-containing compound, together with sulphur or a sulphur-containing compound, at the reduction stage, most of the residual non-metallic iron can be solubilised as well as a proportion of the manganese.
According to the present invention, there is provided a process for the beneficiation of a titaniferous iron ore containlng manganese impurities which process com~rises forming a mixture consisting essentially of the ore and sodium chloride and sulphuror a sulphu~containing compound. The mixture is ~'~ heated at a temperature within the range o~ 1000C to 1250C
in the presence of a reducing agent to provide a reduced ore rich in titanium dioxide in which metallic iron has been solubilised.
The reduced ore is leached to extract the iron therefrom, the ,. ~
;~ ~ sodium chloride and the sul~hur or sulphur-containing compound being added in amounts effective to inhibit the production of , an unleachable Ti3Q5 anosovite phase during the reduction stage and thereby increase the degree of metallization, but in amounts such that the proportion of the sodium chloride together with the sulphur or sulphur-containing compound is in the range of from ~.1% to 10% by weight of the ore.
. . : , ~3g33 As indicated above, the process of the invention is especially concerned with the beneficiation of ilmenite.
The preferred chlorine-containing compounds are metallic chlorides, most preferably sodium chloride. The preferred quantities of sodium chloride added at the reduction stage generally range from 0.1~ to 10% by weight of the ore, but can be as high as 20%. Other chlorides may be used in equiva-lent quantities.
The sulphur-containing compound may be a solid or a gaseous compound. The latter may be SO2 while the preferred solid compounds are metallic or ammonium sulphates, such as sodium sulphate, sodium bisulphate, ammonium sulphate, most preferably iron sulphate. These may be added in quantities of 0.1% - 10~ by weight of the ore.
The weight ratio of the sulphur or sulphur-containing compound to the chlorine-containing compound can be widely varied but it is preferably in the range 1:20 to 20:1.
The preferred reduction temperature and time are in the ranges 1000C to 1250C, and 1/2 to 16 hours respectively.
Any suitable reductant known per se in the art may be used; for example, reducing gases such as hydrogen, carbon monoxide or hydrocarbons, including natural gas, producer or water gas and refor~ed naphtha; liquid hydrocarbons, such as , ~ , fuel oll; or solid reductants such as coke or coal; and mix-tures of any such reductants.
Leaching of the reduced product can also be carried out with any suitable leachant known per se in the art. The most preferred technique is to remove the metallic iron by accelerated rusting in an aqueous medium. Alternatively or ; 30 additionally acid leaching may be used, this being especially useful where significant amounts of manganese are to be removed.
The process of the invention can be applied to previously ^ '' ' .
upyraded ores, such as an upgraded ilmenite containing say in excess of 85% TiO2 to reduce the residual iron and manganese impurit,ies, or it can be applied to the as-mined or dressed ore. All such materials are to be considered as falling within the scope of the term "ore" as used herein. The invention is applicable to the treatment of such ores by either batch or continuous reductive roasting processes.
As thus applied, the process of the invention overcomes, at least in part, the adverse effects of the presence of small amounts of manganese and residual Fe2+ in stabilising the M305 solid solution phase by reducing the amount of manganese available for incorporation into the M305 phase. The amount of iron incorporated into the M305 phase is decreased and the amount of iron that can be reduced to the metallic state is consequently increased.
The invention will now be further descri~ed with refer-ence to the following non-limitative examples.
; EXAMPLE 1 :
A reduction kiln 2.4m in diameter by 30m in length was fed with hot pre-oxidised ilmenite and maintained at a temperature of 1150C to 1200C, by the use of coal. The !~ ` oxidised ilmenite was fed to this kiln at the rate of 2.2 - 2.6 tph and the sodium chloride and sulphur added at the rate of 1.65 -2.0% by weight of the ilmenite and 0.6% by weight of the ilmenite, respectively. The product from the reduction kiln ' ~ was cooled and the reduced ilmenite separated from the residual ,~ char by means of screening and magnetic separation. The reduced ilmenite was then treated by an accelerated rusting process to remove metallic iron and then finally leached with , ~ 4~% sulphuric acld. The final product resulting form this treat-ment contained between 92.0 - 93.3% Tio2, a total iron content ~ B - 6 -' ' ":
of 2.2% and a manganese content of 1.1% expressed as MnO. Without the addition of the additives the material would normally contain approximately 4-5% total iron and 1.7-1.8~ Mn expressed as MnO.
EXA~PLE 2 Samples of oxidised ilmenite were reduced at 1150C
with Collie Coal char, and with the addition of varying amounts of a mixture of sodium chloride and sodium sulphate. After reduction the reduced ilmenite was leached with HCl `~
, j~ :
I
:,: :
' :`
. ~ .
`::
~ , .
., to remove metallic iron and then with 4% sulphuric acid to remove any solubilised manganese. The results are plotted graphically in the accompanying drawing. It will be noted that very substantial removal of the manga-nese has been achieved in these tests and tha-t the addition of sodium chloride has allowed manganese removal to take place at lower concentrations of sulphate.
Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described.
It is to be understood that the invention includes all such variations and modifications which fall within its spirit an~ scope~
The phase diagram of McChesney and Muan referred to above appears in Amer. Mineral, 46, 1961, 572-82.
' ~ ~ 25 '~ ' - , : 30 ' ,
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the beneficiation of a titaniferous iron ore containing manganese impurities which process comprises forming a mixture consisting essentially of said ore and sodium chloride and sulphur or a sulphur-containing compound, heating said mixture at a temperature within the range of 1000°C to 1250°C in the presence of a reducing agent to provide a reduced ore rich in titanium dioxide in which metallic iron has been solubilised, and leaching said reduced ore to extract the iron therefrom, the sodium chloride and the sulphur or the sulphur-containing compound being added in amounts effective to inhibit the production of an unleachable Ti3O5 anosovite phase during the reduction stage and thereby increase the degree of metallization, but in amounts such that the proportion of the sodium chloride together with the sulphur or sulphur-containing compound is in the range from 0.1% to 10%
by weight of the ore.
by weight of the ore.
2. A process according to Claim 1, in which the sulphur-containing compound is a metallic sulphate.
3. A process according to Claim 2, in which the metallic sulphate is selected from the group consisting of sodium sulphate, sodium bisulfate and iron sulphate.
4. A process according to Claim 1, in which the sulphur-containing compound is ammonium sulphate.
5. A process according to Claim 1, in which the weight ratio of the sulphur or sulphur-containing compound to the sodium chloride is in the range 1:20 to 20:1.
6. A process according to Claim 1, in which the ore is heated in the reduction stage for a period of between 1/2 and 16 hours.
7. A process according to Calim 1, in which the leaching step comprises accelerated rusting in an aqueous medium.
8. A process according to Calim 1, in which the leaching step comprises leaching with mineral acid.
9. A process according to Claim 1, in which the titani-ferous iron ore is ilmenite.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPC746676 | 1976-09-22 | ||
| AUPC7466/76 | 1976-09-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1103933A true CA1103933A (en) | 1981-06-30 |
Family
ID=3766774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA287,207A Expired CA1103933A (en) | 1976-09-22 | 1977-09-21 | Method of upgrading a titaniferous ore utilising reductive roasting |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1103933A (en) |
| GB (1) | GB1588440A (en) |
| MY (1) | MY8200161A (en) |
| NZ (1) | NZ185224A (en) |
| ZA (1) | ZA775662B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU639089B2 (en) * | 1990-03-02 | 1993-07-15 | Wimmera Industrial Minerals Pty. Ltd. | Production of synthetic rutile |
-
1977
- 1977-09-20 GB GB39190/77A patent/GB1588440A/en not_active Expired
- 1977-09-21 ZA ZA00775662A patent/ZA775662B/en unknown
- 1977-09-21 NZ NZ185224A patent/NZ185224A/en unknown
- 1977-09-21 CA CA287,207A patent/CA1103933A/en not_active Expired
-
1982
- 1982-12-31 MY MY1982161A patent/MY8200161A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| NZ185224A (en) | 1979-12-11 |
| MY8200161A (en) | 1982-12-31 |
| ZA775662B (en) | 1978-07-26 |
| GB1588440A (en) | 1981-04-23 |
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