Production of Titanium Powder Directly from Titanium Ore by Preform Reduction Process (PRP)

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1 Production of Titanium Powder Directly from Titanium Ore by Preform Reduction Process (PRP) Haiyan Zheng 1 & Toru H. Okabe 2 1: Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan 2: International Research Center for Sustainable Materials, Institute of Industrial Science, The University of Tokyo, Tokyo, Japan The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 1

2 Production of Titanium Powder Directly from Titanium Ore by Preform Reduction Process (PRP) 1. Introduction Background Previous research works Purpose of this study 2. Experimental 3. Experimental results 4. Summary and future works The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 2

3 Titanium? Aerospace industry Features of Titanium 1. Light and high-strength 2. Corrosion resistance 3. Biocompatibility 4. 9th most abundant element in the earth s crust Ocean industry Implant Japan Aerospace Exploration Agency Buildings The JAPAN TITANIUM SOCIETY TMinato-Machi River Place (Osaka Japan) The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 3

4 Current status of titanium production (a) Production of titanium sponge in the world (2003) (b) Transition of production volume of titanium mill products in Japan USA 8 kt Kazakhstan 9 kt China 4 kt Total 65.5 kt Japan 18.5 kt (28% share) Russia 26 kt Amount of titanium mill products [kt] kt (2003) 1980 Year Japan has about 30% world market share, and its titanium industry is growing steadily The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 4

5 Comparison with common metals Metal Iron Aluminum Titanium Symbol Fe Al Ti Melting point (K) Density (g/cm K) Specific strength ((kgf/mm 2 )/(g/cm 3 )) 4~7 3~6 8~10 Clarke No Price ( /kg) ~ ~3000 Production volume (t/world@2003) 9.6 x x x /300 1/15000 Production volume of metallic Ti is substantially small compared to common metals. The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 5

6 Kroll process Chlorination: Ti ore (s) + C (s) + 2 Cl 2 (g) TiCl 4 (l) + MCl x (s, g) + CO 2 (g) M: Impurity element in the ore Reduction: TiCl 4 (l) + 2 Mg (s) Ti (s) + 2 MgCl 2 (l) Electrolysis: MgCl 2 (l) Mg (s) + Cl 2 (g) Reduction reactor for the Kroll process Mg & TiCl 4 feed port Mg & MgCl 2 recovery port Metallic reaction vessel Titanium sponge Ti / Mg / MgCl 2 mixture Furnace The essential advantage: High-purity Ti obtainable The critical disadvantage: Batch type process Labor and energy consuming Slow production speed Low productivity The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 6

7 Various reduction processes for titanium oxides (a) FFC process (Fray et al.) (b) OS process (Ono & Suzuki) e - TiO 2 powder e - (c) EMR / MSE process (Okabe et al.) Current monitor / controller e - e - Carbon anode TiO 2 preform CaCl 2 molten salt Carbon anode CaCl 2 -CaO molten salt TiO 2 Ca-X alloy Carbon anode Ca CaCl 2 molten salt (d) Preform reduction process (PRP) Feed preform (TiO 2 feed + flux) Reductant vapor Reductant (R = Ca, or Ca-X alloy) The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 7

8 The purpose of this study Development of a new smelting process for producing high purity titanium. High productivity, low cost process has to be developed for replacing the Kroll process Preform reduction process (PRP) Feed preform (TiO 2 feed + flux) Reductant vapor Reductant (R = Ca, or Ca-X alloy) TiO 2 (s, feed preform) + Ca (g) Ti (s, powder) + CaO (s, flux) The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 8

9 Production of Titanium Powder Directly from Titanium Ore by Preform Reduction Process (PRP) 1. Introduction 2. Experimental Concept of PRP Flowchart of this study PRP experiment with no carbon powder PRP experiment with carbon powder 3. Experimental results 4. Summary and future works The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 9

10 Preform Reduction Process (PRP)? Feed preform (TiO 2 feed + flux) Reductant vapor Reductant (R = Ca, or Ca-X alloy) TiO 2 ore or UGI TiO 2 preform Ti powder Starting material Preform Powder TiO 2 (s, feed preform) + Ca (g) Ti (s, powder) + CaO (s, flux) Advantages of Preform Reduction Process: simple and low-cost process Suitable for uniform reduction Flexible scalability Possible to control the morphology of powder by varying the flux content in the preform Possible to prevent the contamination from reaction container Amount of waste solution is minimized Molten salt as a flux can be reduced compared to other direct reduction process Disadvantages of Preform Reduction Process: Leaching process is required Calcium production and control of calcium vapor is difficult The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 10

11 Ellingham diagram of some selected oxides Standard Gibbs energy of formation, ΔG f / kj mol /2 Fe + O 2 =1/2 Fe 3 O 4 1/2 Fe + O 2 = 1/2 FeO 4 Na + O 2 = 2 Na 2 O Si + O 2 = SiO 2 Ti + O 2 = TiO 2 4/3 Al + O 2 = 2/3 Al 2 O 3 2 Mg + O 2 = 2 MgO 2 Ca + O 2 = 2 CaO Temperature, T / K Fig. Ellingham diagram of some selected oxides. Only Ca can be utilized as reductant for the production of metallic Ti with low oxygen content directly from Ti ore. TiO 2 (s) + Ca (g) Ti-1000ppmO Ti-100ppmO Ti-10ppmO Ti (s) + CaO (s) ~500ppmO The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 11

12 Vapor pressure of some selected metals and chlorides 1273 K (Reaction temperature) 0-2 K Na Range of vapor pressure feasible for supplying reductants in vapor form The vapor pressure of Ca: K Vapor pressure, log p i (atm) TiCl 3 Ca MgCl 2 KCl Mg Ca reductant can be supplied as vapor form for reducing Ti ore or TiO 2 in the PRP. -10 NaCl CaCl 2 TiCl 2 Ti Temperature, T / K Fig. Vapor pressure of selected metals and chlorides. The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 12

13 Starting materials Previous study: Artificial feed materials TiO 2 powder Upgraded ilmenite (India) Titanium Powder Or De-ionized ilmenite ore 99 % up matellic titanium powder was obtained by using titanium oxide (TiO 2 ) or upgraded ilmenite (UGI) as the staring materials. This study: Natural titanium ore (Rutile, South Africa) used as feed material Rutile ore (South Africa) XRF analysis (mass %) Ti Fe Al Ca Cl (0.00) So far, it was difficult to produce high-purity Ti directly from natural Ti ore! The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 13

14 Experimental procedure Ti ore Flux Binder Mixing Slurry Ti ore: Rutile Flux: CaCl 2 Binder: Collodion Rutile+CaCl 2 +Binder T: Room temp.; t : 6 hr e.g. 40mm 20mm 8mm Preform fabrication Feed preform Ti ore + flux T: 1273 K; t : 1 hr~ 2hr T: 1273 K, t : 6 hr~9 hr Calcium vapor T: RT 50% CH 3 COOH aq., t : 6 hr 20% HCl aq., t : 1 hr Calcination/iron removal Sintered feed preform Reduction Reduced preform Leaching Vacuum drying FeCl x TiO 2 feed in flux Ti + CaO + Ca Waste solution Ti powder Powder The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 14

15 Experimental apparatus for the reduction process in PRP TIG welding Stainless steel reaction vessel Stainless steel cover Feed preform after Fe removal Stainless steel net Stainless steel holder Reductant (Ca granules) Ti sponge getter 1 cm Fig. Schematic illustration of the experimental apparatus for the reduction experiment. Fig. Arrangement of stainless steel net and holder tentatively installed in transparent container. The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 15

16 Experimental conditions Table Experimental conditions in this study. Exp. A(C-2) B(C-7) C(PCD-2) D(PCD-4) a b Feed Ti ore a Mass of sample, w i / g Flux CaCl Binder Collodion Additive Carbon powder Cationic Molar ratio., R Cat. / Ti b Natural rutile ore produced in South Africa after pulverization. Cationic molar ratio, R Cat. / Ti = N Cat. / N Ti, where N Cat. and N Ti are mole amount of cation in flux and that of titanium, respectively Calcination Temp., Time, T cal. / K t' cal. / hr Fe removal Reduction Temp., Time, T red. / K t' red. / hr Ti powder production The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 16

17 Production of Titanium Powder Directly from Titanium Ore by Preform Reduction Process (PRP) 1. Introduction 2. Experimental 3. Experimental results Analytical data by XRD, XRF, and SEM 4. Summary and future works The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 17

18 (a) Fabricated feed preform Experimental results: Images and XRD Exp. A, Cationic molar ratio, R = 0.2 XRD patterns : TiO 2 : CaCl 2 : CaCl 2 (H 2 O) 4 JCPDS # JCPDS # JCPDS # Ti ore + flux TiO 2 + CaCl 2 + CaCl 2 (H 2 O) 4 (b) After calcination TiO 2 feed in flux (c) After reduction Ti + CaO + Ca Intensity, I (a.u.) : TiO 2 : CaCl 2 : CaCl 2 (H 2 O) 4 JCPDS # JCPDS # JCPDS # : Ti JCPDS # : Ca JCPDS # : CaO JCPDS # TiO 2 + CaCl 2 + CaCl 2 (H 2 O) 4 Ti + CaO + Ca (d) After leaching : Ti JCPDS # Ti powder Ti Angle, 2θ (deg.) 100 A(C-2) The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 18

19 Experimental results: SEM images and XRF SEM images (a) Fabricated feed preform Step Exp. B, Cationic molar ratio, R = 0.3 XRF analysis (mass %) Ti Fe Al Ca Cl 5μm (b) After calcination (a) Iron removal ratio is 56 % 5μm (c) After reduction (b) μm (d) After leaching (c) (0.00) μm (d) (0.00) Iron removal ratio: (C Fe, Bef. /C Ti, Bef. C Fe, Aft. /C Ti, Aft. ) / (C Fe, Bef. /C Ti,Bef. ) B(C-7) The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 19

20 After leaching XRD pattern Experimental results: XRD, SEM images, and XRF Exp. C, Cationic molar ratio, R = 0.2, Carbon powder: 0.2 g Step XRF analysis (mass %) Ti Fe Al Ca Cl : Ti JCPDS # SEM images (a) After fabrication (b) After calcination Iron removal ratio is 90 %. (c) After reduction (0.00) μm (d) After leaching (0.00) Iron removal ratio: (C Fe, Bef. /C Ti, Bef. C Fe, Aft. /C Ti, Aft. ) / (C Fe, Bef. /C Ti,Bef. ) C(PCD-2) The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 20

21 After leaching XRD pattern Experimental results: XRD, SEM images, and XRF Exp. D, Cationic molar ratio, R = 0.3, Carbon powder: 0.2 g Step XRF analysis (mass %) Ti Fe Al Ca Cl : Ti JCPDS # SEM images (a) After fabrication (b) After calcination Iron removal ratio is 65 %. (c) After reduction (0.00) μm (d) After leaching (0.00) Iron removal ratio: (C Fe, Bef. /C Ti, Bef. C Fe, Aft. /C Ti, Aft. ) / (C Fe, Bef. /C Ti,Bef. ) D(PCD-4) The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 21

22 Composition and yields of the obtained Ti product Exp. Cationic molar ratio, R Cat./Ti Ti Fe Exp. C and D Table Analytical results of the titanium samples obtained after leaching. Concentration of element i in obtained Ti powder, C i (mass %) Al Ca Cl Yield (%) C (0.00) D (0.00) a b Natural rutile ore produced in South Africa after pulverization. Cationic molar ratio, R Cat. / Ti = N Cat. / N Ti, where N Cat. and N Ti are mole amount of cation in flux and that of titanium, respectively. Still high for practical application, but will be improved. Loss occurred mainly at leaching process. The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 22

23 Production of Titanium Powder Directly from Titanium Ore by Preform Reduction Process (PRP) 1. Introduction 2. Experimental 3. Experimental results 4. Summary and future works The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 23

24 Summary 1. Iron was successfully removed by selective chlorination in the calcination step, and 90 % of iron was removed. 2. When carbon powder is added to the preform, the effect of iron removal became more efficient. Titanium powder with 98 mass % purity was obtained with the yield of 88 %. 3. High-purity metallic titanium powder (99 mass % up) was obtained directly from natural titanium ore (rutile ore) by Preform Reduction Process (PRP). The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 24

25 Future Works 1. Development of more effective method for removing iron directly from titanium ore. 2. Development of efficient recycling system of CaCl 2 flux, and residual Ca reductant. The ultimate object: establishing an innovative process for producing high-purity titanium powder with low-cost. Natural Ti Ore or UGI Low iron, low oxygen Ti powder The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 25

26 Production of Titanium Powder Directly from Titanium Ore by Preform Reduction Process (PRP) Ti ore Flux Binder Mixing Slurry Ti ore: Rutile Flux: CaCl 2 Binder: Collodion Rutile+CaCl 2 +Binder T: Room temp.; t : 6 hr e.g. 40mm 20mm 8mm Preform fabrication Feed preform Ti ore + flux 0.8~1.4 mass % Fe T: 1273 K; t : 1 hr~ 2hr T: 1273 K, t : 6 hr~9 hr Calcium vapor T: RT 50% CH3COOH aq., t : 6 hr 20% HCl aq., t : 1 hr Calcination/iron removal Sintered feed preform Reduction Reduced preform Leaching Vacuum drying Powder FeCl x Waste solution TiO 2 feed in flux Ti + CaO + flux Ti powder 90 % Fe removal ~0.13 mass % Fe 98 mass % up purity 0.14 mass % Fe 88 % yield The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 26

27 Acknowledgments The University of Tokyo Professor Masafumi Maeda Professor Yoshitaka Mitsuda Kyoto University Dr. Tetsuya Uda Toho Titanium Co. Ltd Mr. Susumu Kosemura, Mr. Masanori Yamaguchi, and Mr. Yuichi Ono Okabe Lab at the University of Tokyo Mr. Itaru Maebashi, Mr. Osamu Takeda and Mr. Ryosuke Matsuoka (Currently at Cabot Co. Ltd.) Special thanks to Mr. Yuichi Mashimo and Mr. Hiromasa Ito A part of this research was financially supported by Grant-in-Aid for Young Scientists from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) and also by Central Research Institute of Electric Power Industry (CRIEPI). The 21 st Rare Metal Meeting; March 10, 2006 Institute of Industrial Science, the University of Tokyo 27