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
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
• • 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
  • C22B5/00—General methods of reducing to metals
• • 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
• • 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
  • C22B34/1263—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 metallic titanium from titanium compounds, e.g. by reduction
  • C22B34/1281—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 metallic titanium from titanium compounds, e.g. by reduction using carbon containing agents, e.g. C, CO, carbides
• • 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
  • C22B34/129—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 metallic titanium from titanium compounds by dissociation, e.g. thermic dissociation of titanium tetraiodide, or by electrolysis or with the use of an electric arc
• • 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
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/18—Reducing step-by-step
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
  • C25C3/26—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium
  • C25C3/28—Electrolytic production, recovery or refining of metals by electrolysis of melts of titanium, zirconium, hafnium, tantalum or vanadium of titanium
• • 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
  • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
  • C22B7/04—Working-up 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

Definitions

• the present invention relates to the production of metals.
• the invention has particular utility in connection with the production of titanium and will be described in connection with such utility, although other utilities are contemplated, e.g., production of other high value multi- valence and high (2 or more) valance metals, in particular refractory metals such as chromium, hafnium, molybdenum, niobium, tantalum, tungsten, vanadium and zirconium which are given as exemplary.
• refractory metals such as chromium, hafnium, molybdenum, niobium, tantalum, tungsten, vanadium and zirconium which are given as exemplary.
• the properties of titanium have long been recognized as a light, strong, and corrosion resistant metal, which has lead to many different approaches over the past few decades to extract titanium from its ore.
• TiCl 4 titanium tetrachloride
• TiCU is reduced with molten magnesium at ⁇ 800 0 C in an atmosphere of argon.
• titanium Since titanium's discovery, investigations have been conducted to produce titanium by more economical processing other than the metalothermic reduction such as magnesium or sodium reduction of TiCl 4 , but without sufficient success to replace the high cost Kroll process.
• the intensive interest to develop low cost processing to produce titanium has recently spun several published processes. Since titanium primarily appears as the oxide (TiO 2 ), it can be conceived that an oxide feed to produce titanium could be more economical than making the chloride (TiCl 4 ) by carbo-chlorination of the oxide as the feed (TiCl 4 ) which is used in the Kroll process.
• the US Bureau of Mines performed extensive additional investigations [1,5-8] to improve the Kroll and Hunter processes.
• TiO 2 cathode is not fully reduced which leaves contamination of TiO 2 or reduced oxides such as TiO, mixed oxides such as calcium titanante as well as titanium carbide being formed on the surface of the cathode thus also contaminating the titanium.
• titanium dioxide TiO 2
• SiCl 2 molten calcium chloride
• WO 02/066711 Al The first aspect of the teachings of WO 02/066711 Al is that the electrical contact to the TiO 2 cathode influences the reduction process and that a high resistive electrical conductor to the cathode is made part of the cathode. It is further reported the oxygen removed from the TiO 2 cathode in a pellet form passes onto solution and/or chemically reacts with the electrolyte cation.
• the teaching is that deposition of the cation at the cathode is prevented through controlled potential at under 3.0V in the CaCl 2 electrolyte. It is stated Al 2 O 3 in the cathode with TiO 2 can also be reduced but non-uniformly with the only reduction taking place where the Al 2 O 3 touches the cathode conductor.
• the publication WO 02/066711 Al teaches the TiO 2 must be made into a pellet and presintered before use as a cathode and states the Fray et al. application mechanism is incorrect, produces 18 wt% carbon in the final titanium pellet as well as calcium titanites and silicates if silica is in the titania (TiO 2 ) pellets.
• titania (TiO 2 ) cathode is in the form of a solid such as a plate.
• the potential of the cell must vary with the concentration of oxygen in the titanium requiring higher potentials at lower concentrations of oxygen to remove the lower concentrations of oxygen. It is unlikely to remove the oxygen from TiO 2 to low concentrations (i.e., 500ppm) in a single stage operation. It is again taught that cations must be produced to chemically reduce the cathodic TiO 2 requiring refreshing the electrolyte and/or changing/increasing the cell potential. The method teaches carrying out the reduction of TiO 2 in a series of electrolytic cells of successively transferring the partially reduced titanium oxide to each of the cells in the series.
• the cell potential is above the potential at which Ca metal can be deposited via the decomposition of CaO wherein the Ca metal is dissolved in the electrolyte which migrates to the vicinity of the cathode TiO 2 .
• U.S. Patent 6,663,763 B2 which is substantially the same as international publication WO 02/06671 1 Al, it is taught that CaO must be electrolyzed to produce calcium metal and Ca ++ ions which reduce the titania (TiO 2 ) in the cathode with oxygen (O ⁇ ) migrating to the anode. This is very unlikely the mechanism.
• the produced calcium from electrolysis must diffuse into the titania (TiO 2 ) pellet to achieve chemical reduction as claimed and the formed CaO will then have to diffuse out of the Ti/TiO 2 which has been preformed and sintered into a pellet. If calcium metal (Ca 0 ) or ions (Ca ++ ) are produced by electrolysis, the oxygen ions (O ⁇ ) produced from that electrolysis can diffuse to the anode.
• US Patent 6,540,902 Bl to Redey teaches that a dissolved oxide in the electrolyte is required to cathodically reduce a metal oxide such as UO 2 .
• the example is Li 2 O in LiCl and the oxygen-ion species is dissolved in the electrolyte for transport to the anode which is shrouded with a MgO tube to prevent back diffusion of oxygen. It is reported the cathodic reduction of the oxide (examples UO 2 and Nb 2 O 3 ) may not take place if the cathode is maintained at a less negative potential than that which lithium deposition will occur.
• the electrolyte (LiCl) should contain mobile oxide ions which may compress titanium oxide whose concentration of the dissolved oxide species are controlled during the process by controlled additions of soluble oxides. Which titanium oxide is not defined, however, as there are a plethora of different titanium oxides. It is generally known titanium oxides are not soluble in molten salts which accounts for the fact titanium is not electrowon from an oxide feed analogous to aluminum being electrowon from the solubility OfAl 2 O 3 in cryolite/sodium fluoride.
• a liquid slag containing titantia is used as a cathode on a cell bottom with an electrolyte such as CaF 2 floating on top and in contact with anodes such as graphite.
• an electrolyte such as CaF 2 floating on top and in contact with anodes such as graphite.
• the impure metals such as iron are deposited at the molten electrolyte titania slag interface and sink to the bottom of the slag since the iron is heavier.
• titanium is reportedly deposited at the molten slag electrolyte interface and also sinks through the slag settling to the bottom of the cell for subsequent tapping. Oxygen ions diffuse through the electrolyte to an upper anode of graphite.
• oxides such as alumina have not produced pure aluminum by carbothermic reduction.
• TiO 2 heretofore has not been carbothermically reduced to produce pure titanium.
• U.S. Serial No. 10/828,641 filed April 21 , 2004, we describe how TiO 2 could be carbothermically reduced to TiO.
• Further investigations have shown it is possible to carbothermically remove more oxygen from the TiO to produce a suboxide of titanium, i.e., having a ratio of oxygen to titanium less than one. The more oxygen removed by the highly efficient and low cost carbothermic reduction, the less required to be removed by electrons in electrolytic reduction which frequently is quite inefficient.
• Titanium is the fourth most abundant metal in the Earths' crust in several mineral forms.
• the most common utilized minerals are rutile (TiO 2 ) and ilmenite (FeTiO 3 ).
• Calcium titanates are also an abundant source which contains the element titanium.
• TiO 2 Utilized as mined or purified through various leaching and/or thermal processing's TiO 2 is the most utilized compound which has applications as pigment and for carbo chlorination to produce TiCl 4 which is reduced with metals such as magnesium (Kroll Process) or sodium (Hunter Process) that produces titanium metal or the chloride is oxidized to produce a highly purified pigment.
• Titanium exists in multivalent species of Ti +4 , Ti + , and Ti + in various anionic compositions such as the oxide or chloride. Except for the oxide those compounds are typically unstable in the ambient atmosphere. In general there has been limited application of these subvalent compounds which has not generated processing to produce the subvalent oxides or others compounds.
• the high cost of titanium metal has limited its usage to critical aerospace where weight reduction over rides cost sensitivity. Because of the high cost of producing titanium by the Kroll or Hunter processes the cost volume ratio of titanium has tended to be inelastic. The holy grail of titanium is to reduce the cost of the primary metal as well as down stream processing cost. Initiatives are known to be underway to improve efficiency and reduce cost of the basic Kroll and Hunter processes as well as alternative processing involving electrolytic processing.
• the latter process consist of alumina (Al 2 O 3 ) exhibiting solubility in fused cryolite (Na 3 AlF 6 ) which is electrolyzed with a carbon anode that produces CO 2 with some CO and the metal aluminum.
• alumina Al 2 O 3
• fused cryolite Na 3 AlF 6
• CO 2 carbon anode
• the suboxides of titanium can exhibit solubility in some fused salts that may include the alkali, alkaline earth and rare earth halides.
• no reliable low cost process has been available to produce the titanium suboxides that could be used as a feed to electrolytically produce titanium.
• the titanium suboxide could be utilized cathodically and electrolytically reduced to titanium metal without the calcium titanate problem when using TiO 2 , and the titanium suboxide could be dissolved in fused salts with electrolysis with a carbon or inert anode to produce titanium. Either processing extreme can produce titanium more economically then the Kroll or Hunter processes.
• the SiO 2 can be reduced with other reductants but the product is contaminated with the reductant as well as unwanted other compounds can be produced.
• SiO 2 + C + heat SiO and SiC + CO.
• Producing a titanium suboxide by reducing TiO 2 with titanium metal is uneconomical since titanium metal must first be produced.
• carbon is utilized as the reducing agent, titanium carbide is typically a contaminate. Titanium carbide has a very high free energy of formation which is exceeded only by zirconium and hafnium carbide. The free energy of formation of TiC is approximately 183 KJ/mole which makes it formation prominent in any carbon reduction process.
• carbon is meant to include carbon in any of its several crystalline forms including, for example, graphite.
• Figs. 1-3 show the XRD patterns of stoichiometric TiO 2 -C heat treated in argon at 130O 0 C, 1400 0 C and 175O 0 C for one hour, respectively;
• Fig. 4 shows thermodynamic equilibrium patterns thereof;
• FIG. 5 shows the XRD patterns of stoichiometric TiO 2 -C heat treated to 145O 0 C in one step followed by heat treatment at 2100 0 C in vacuum
• Fig. 6 shows the XRD patterns of 1 : 1 :TiO 2 -Ti heat treated to 176O 0 C in vacuum
• Fig. 7 shows the XRD patterns of stoichiometric TiO 2 -C heat treated to 145O 0 C with a second heat treatment to 1800 0 C in high vacuum
• Fig. 8 shows the XRD patterns of stoichiometric TiO 2 -C from phenolic in a pre- mix heat to 145O 0 C at one atmosphere pressure in argon
• FIG. 9 shows the XRD patterns of stoichiometric TiO 2 -C from a 110 0 C softening point coal tar pitch mixed at 19O 0 C and heat treated at 165O 0 C at atmospheric pressure in argon;
• Fig. 10 shows the XRD patterns of slag-C from a HO 0 C softening point coal tar pitch mixed at 19O 0 C and heat treated at 165O 0 C at atmospheric pressure in argon;
• Fig. 11 shows the XRD patterns for Ilmenite ore treated with an intimate carbon coating on ore particles with heat treatment to 1650 0 C in argon;
• Fig. 10 shows the XRD patterns of stoichiometric TiO 2 -C from a 110 0 C softening point coal tar pitch mixed at 19O 0 C and heat treated at 165O 0 C at atmospheric pressure in argon;
• Fig. 11 shows the XRD patterns for Ilmenite ore treated with an intimate carbon coating
• Fig. 12 shows the XRD patterns for Ilmenite ore treated with an intimate carbon coating on ore particles with heat treatment to 165O 0 C in argon plus 1800 0 C in a vacuum lower than lO "3 Torr;
• Fig. 13 shows the XRD patterns of TiO 2 treated with an intimate mixture of carbon with heat treatment to 2100 0 C at atmospheric pressure in argon;
• Fig. 14 shows the XRD patterns for Anatase TiO 2 with an intimate mixture of carbon with heat treatment to 2100 0 C under argon at atmospheric pressure.
• the small variation in compositions suggests the graphite crucible is not the major contribution to the formation of TiC.
• Duplicate experiments were run but instead of atmospheric argon, a vacuum was generated with a fore pump to about 0.1 atmosphere.
• the TiC concentration was reduced to approximately 20%, with 30% TiO and 50% Ti 2 O 3 .
• the TiC composition was reduced with an increase in Ti 2 O 3 .
• the TiC is in a +4 valence state and unacceptable as a reduced valence state feed for electrolytic producing titanium.
• a thermodynamic equilibrium calculation was performed as shown in Fig. 4 which indicates that TiC is a major product component above about 1100°C.
• a two step heat treatment was performed which consisted of first heating to 145O 0 C and then in a second step heating to 2100 0 C in vacuum of approximately 0.1 atmosphere.
• TiO was formed as shown in Fig. 5.
• heating to 2100 0 C in vacuum is an expensive batch operation not conducive to commercial production of titanium at low cost, consequently less severe heat treatments were investigated to produce TiO.
• Example liquid precursors that have a high yield of carbon when pyrolized are furfural alcohol, resins such as phenyol formalide (phenolics) and pitches (coal and petroleum tars). Sugars and other materials can be used but their carbon char yield is low. Pitches have melting points from under 100 0 C up to nearly 400 0 C.
• TiO 2 was mixed with phenolic resin such as Borden B1008 and heated to form a solid at approximately 11O 0 C.
• TiO 2 was mixed with a 11O 0 C softening point coal tar pitch at a mixing temperature of 19O 0 C.
• the char yield on the phenolic or coal tar pitch is approximately 50%.
• a stoichiometric mixture of each type of precursor was heated to temperatures of 1300 0 C to 165O 0 C with the results subjected to XRD analysis. The lower temperature, the 145O 0 C example is shown in Fig. 8.
• the major portion is TiO but some higher oxide OfTi 2 O 3 remains; however, the amount of TiO produced is greater than when only particles of carbon and TiO 2 were heated together, and importantly no TiC was formed.
• the XRD of the sample heated to 165O 0 C is shown in Fig. 9. At this temperature of 165O 0 C heating at atmospheric pressure pure TiO is produced.
• the atmospheric pressure treatment is quite economical and the pure TiO produced can be used to electrolytically produce low cost titanium, e.g., by the electrochemical reduction method described in our aforementioned parent application.
• the intimate mixing of the carbon precursor with the metal oxide can also be used to purify titania type ores.
• Titania slag which is a by product of pig iron production from ilmenite ore, obtained through QIT in Canada which has the composition shown in Table 1 was mixed with a 110 0 C softening point coal tar pitch at 19O 0 C to obtain an intimate mixture of the carbon precursor and the slag particulate.
• Table 1- Composition of TiO 2 slag, a byproduct of pig iron production from Ilmenite.
• the mixture was heated to 165O 0 C in an argon inert atmosphere wherein the coal tar pitch was pyrolized with the heat treatment producing carbon in intimate contact with the titania slag particulate.
• the intimate carbon contact with the slag particulate produced TiO with the composition shown in Table 2.
• Ilmenite which is iron titanite FeTiO 3 with a variety of impurities consists typically of the composition shown in Table 3. Table 3-Composition of Ilmenite ore.
• the ilmenite ore was mixed with 110 0 C softening point coal tar pitch heated to 19O 0 C to provide intimate mixture of stoichiometric carbon and the ilmenite ore particles.
• the mixture was heated to 165O 0 C heat treatment in an inert atmosphere which pyrolized the pitch providing intimate contact of the carbon on metal oxide particles.
• the chemical composition after the 165O 0 C in an inert atmosphere which pyrolized the pitch providing intimate contact of the carbon on the metal oxide particles is shown in Table 4 and the XRD in Fig. 11.
• Fig. 11 shows iron metal is present.
• the iron metal can be removed by leaching and/or complexing in an aqueous solution at ambient temperature.
• the iron and other impurities can be removed by heating in a vacuum less than 10 "3 Torr to 1800 0 C after or instead of the 165O 0 C heat treatment.
• the purity of the high vacuum 1800 0 C treated material is shown in Table 5 and the XRD in Fig. 12.
• Example 1 - Preparation 1.
• a TiO 2 pigment type feed obtained from the DuPont Company was mixed with powdered coal tar pitch (CTP) and a solvent of normal methyl pyrrolidone (NMP). The ratio was 80 parts TiO 2 and 30 parts of a 1 10 0 C CTP and 80 parts of NMP.
• the NMP provides good fluidity of the mix and dissolves a portion of the CTP. After mixing by stirring, signal blade mixing, ball milling, attrition milling, etc. the mix is heated to evaporate the NMP for collection and reuse.
• the TiO 2 particulate is fully coated and intimately mixed with the pitch which chars or cokes to about 50% carbon with continued heating.
• the mixture was heated to 1700 0 C under atmosphere pressure in a non-oxidizing atmosphere which is typically argon, CO 2 , CO, etc. Nitrogen atmosphere is avoided to prevent the formation of titanium nitride.
• a non-oxidizing atmosphere typically argon, CO 2 , CO, etc. Nitrogen atmosphere is avoided to prevent the formation of titanium nitride.
• the product was pure TiO with an XRD pattern analogous to that shown in Fig. 9.
• the produced TiO was utilized in four different trials to electrolytically produce titanium particulate. The trials were as follows:
• Trial 1- The TiO was mixed with a 110 0 C coal tar pitch which served as a binder and carbon black particulate to provide a stoichiometric mixture of TiO and carbon based on an off gas of 1 : 1 CO 2 /CO. The mixture was pressed in a steel die at 19O 0 C to provide a solid on cooling. The composite anode was heated in an inert atmosphere to 1200 0 C which pyrolized/carbonized the pitch binder. Resin or other precursors which yield carbon on heating in an inert atmosphere are satisfactory binders for producing a solid anode. The composite anode was utilized in a fused salt electrolyte consisting of the tri-eutectic of Li-K-Na chlorides.
• any fused salt mixture of the alkali and/or alkali halides are satisfactory as an electrolyte.
• a stainless cathode was used in a cell maintained in an inert atmosphere with electrolysis at 1 amp/cm 2 which produced titanium metal particulate in the size range of 10-500 microns.
• TiO was used as a cathode in a salt composition of 80% CaCl 2 -20% LiCl operated at 85O 0 C.
• the TiO was ground to minus 100 mesh (147 microns).
• the TiO particles were placed in a stainless steel mesh and placed in the salt electrolyte as a cathode with a graphite anode.
• a potential of 3.0V was applied between the graphite anode and TiO particles contained in the stainless mesh cathode.
• the cathodic particles were analyzed as titanium metal with a residual oxygen content of 2500 parts per million.
• the anode gas was analyzed with a mass spectrometer to be primarily CO 2 with traces of CO.
• Trial 3- The same electrolyte as in Trial 2 was utilized at the same temperature of 85O 0 C.
• the TiO was ground to a minus 325 mesh (less than 44microns).
• Two weight percent TiO was added to the electrolyte with stirring. After one hour stirring a stainless tube cathode was used with a 600 mesh stainless screen covering the bottom of the tube. A graphite rod was placed in the center of the stainless tube. Electrolysis was performed with the stainless tube as the cathode and the graphite rod as the anode. A cathode current density of 1 amp/cm 2 was utilized. After two hours electrolysis of the cathode anode assembly was removed from the salt electrolyte and water washed. Titanium metal particulate was produced in the size range of approximately 1 to 200 microns which demonstrates the TiO had solubility in the electrolyte in order to yield titanium metal on electrolysis.
• Trials 4A and 4B-A closed cell inert atmosphere system was utilized that had tungsten coil resistors between two electrodes in the bottom of the reactor.
• Calcium fluoride (CAF 2 ) was used as the electrolyte and power applied to the tungsten resistors that brought the CaF 2 to a molten state and 1700 0 C.
• CAF 2 Calcium fluoride
• a TiO particle as given in Trial 2 was placed in a molybdenum screen and electrolyzed at 3.0V as a cathode with a graphite anode. Titanium was produced as a molten glob in the molybdenum screen.
• TiO-325 mesh was added to the CaF 2 electrolyte and electrolysis performed between a molybdenum cathode and a graphite anode. Molten droplets of titanium metal were produced at the molybdenum cathode which shows the TiO had solubility in the CaF 2 electrolyte at 1700 0 C producing titanium metal in the molten state due to the electrolysis.
• Example 2 Preparation Ilmenite ore obtained from QIT - Fer et Titane, Inc., of Quebec, Canada, which had the composition shown in Table 3 was mixed at room temperature with 11O 0 C softening point powdered coal tar pitch (CTP) in a ratio of 100 grams of ilmenite ore to 40 grams of CTP and 100 grams of toluene.
• CTP coal tar pitch
• the mixture was ball milled for four hours at room temperature to achieve good mixing and then heated to evaporate the toluene which was collected for reuse.
• the mixture was further heated to 1700 0 C under an inert atmosphere at atmospheric pressure followed by reducing the pressure to 10 " Torr or less and the temperature raised to 1800 0 C and held for one hour.
• TiO is an electronic conductor with a conductivity superior to graphite, electrical contact is easily made which eliminates the necessity to form a partially sintered porous body to serve as a cathode for the electrolytic reduction to Ti metal particles.
• cathodic reduction Of TiO 2 to the metal it is necessary to produce a porous perform in order that current can flow to the TiO 2 body whereas with the high electrolytic conduction of TiO particles are easily contacted to achieve cathodic reduction and making it possible for the continuous cathodic reduction as compared to batch processing of porous TiO 2 preforms.
• the concentrations of titanium and oxygen in TiO are 74.96% titanium and 25.04% oxygen. This composition of TiO is typical of the material such as shown in Fig. 9.
• titanium is desirably obtained carbothermically which results in less electronic reduction in a second electrolysis step to obtain pure metallic titanium with very low oxygen contents of less than 500ppm. Greater carbothermic reduction can be achieved by heating to higher temperatures than the 1650- 1700 0 C as above described. Samples of TiO 2 (the ores of ilmenite, rutile, slag, etc can also be used), and carbon when intimately mixed and heated to higher temperatures, produces a higher titanium content in the remaining product.
• TiO 2 the ores of ilmenite, rutile, slag, etc can also be used
• TiO 2 was intimately mixed at 19O 0 C with coal tar pitch in stoichiometric ratio to produce low oxygen content titanium and was heated to 2100 0 C in a non-oxidizing atmosphere.
• the XRD of the product is shown in Fig. 13.
• a sample was heated to 2800 0 C in a non-oxidizing atmosphere in a graphite container.
• the XRD of that product showed primarily TiC which is believed the graphite crucible contributed to the TiC formation.
• a TiC crucible was fabricated and a TiO 2 -C sample was heat treated to 2800 0 C which resulted in little TiC and a reduced oxygen content of less than TiO in the residual titanium. It is known that when TiO 2 and carbon are heated above about 1200 0 C the product is a mixture of TiO and TiC. It is noted here that TiO 2 when heated at atmospheric pressure and/or at reduced pressure only TiO is produced as exemplified in the XRD patterns shown in Figs. 10, 12 and 13 and verified from carbon and oxygen analysis which showed less than 1% carbon thus ruling out any appreciable amount of TiC formation with a remaining oxygen content depending on the heat treatment temperature of down to about 5% oxygen at 2100 0 C.

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