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
  • C22B34/1218—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 dry processes
  • C22B34/1222—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 dry processes using a halogen containing agent
• • 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
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
  • C22B1/16—Sintering; Agglomerating
• • 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
  • C22B1/00—Preliminary treatment of ores or scrap
  • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
  • C22B1/24—Binding; Briquetting ; Granulating
  • C22B1/242—Binding; Briquetting ; Granulating with binders
• • 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
• • 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

Definitions

• the present invention relates to agglomerates of titanium-bearing material suitable for producing TiCl 4 .
• materials of high titanium dioxide content are the preferred raw materials for TiCl. manufacture, subject to specifications on the particle size of the materials and on the content of some impurity elements.
• TiCl- is a low boiling liquid which may be purified by distillation and chemical methods, following which it may be burned in oxygen to generate Ti0 2 pigment and chlorine gas, or reacted with magnesium or electrolysed to produce titanium metal.
• the raw material a titanium-bearing mineral sized within the range 100 - 300 microns (um) is fed to a fluidised bed reactor where it undergoes reductive chlorination at temperatures in the range 900° - 1000°C. Petroleum coke or a similar high fixed carbon material is added to the bed as both fuel and reducing agent. Oxygen may be added to the inlet stream to maintain reaction temperatures.
• the product TiCl is a low boiling liquid which may be purified by distillation and chemical methods, following which it may be burned in oxygen to generate Ti0 2 pigment and chlorine gas, or reacted with magnesium or electrolysed to produce titanium metal.
• the raw material a titanium-bearing mineral sized within the range 100 - 300 microns (um) is fed to a fluidised bed reactor where
• the reactor passes from the reactor in a gaseous form together with the gaseous chlorides of impurity elements and entrained fine solid particles from the fluid bed.
• the gases are cleaned of solids and condensed.
• the product TiCl. is purified by distillation and chemical methods.
• Impurities such as iron represent an economic penalty to the process in that they consume coke for their reduction and, more importantly, expensive reagent chlorine which is lost in waste iron chlorides. Silicon and aluminium are also partly chlorinated in the process, causing excess chlorine consumption. Aluminium chlorides are also the source of corrosion problems in process equipment.
• fine-grained TiO_-bearing material for fluidised bed chlorination is prepared by coking into composite agglomerated particles a mixture of TiO ⁇ -bearing material, bituminous coking coal and a water soluble binder.
• This prior-art process has not been accepted by the industry.
• the chlorination process is reductive chlorination and so the carbon in the feed material must be present in a specific proportion to the Ti0 2 ⁇ bearing material which may not be suited to composite strength development.
• the agglomerate because the carbon is attacked, breaks down before complete chlorination occurs and so fine particle size material is lost to the process through entrainment in the gas stream.
• a water emulsion of asphalt is used as a binder in the formation by extrusion of pellets of fine-grained titanium-bearing material.
• water is removed from the pellets and the organic material converted to carbon.
• the curing results in the caking of the binder in the pores and around the grains, forming a good bond.
• the extruded material must be broken before curing into a size range close to the required product size. This removes the need for the circulation of cured fines which would otherwise reduce the strength of the product pellets.
• the carbon takes part in the reductive chlorination process. This product therefore suffers from the same disadvantages as those described in the previous example of the prior art.
• the present invention provides a process for increasing the particle size of fines of a titaniferous mineral containing more than 45% by weight titanium which process comprises: mixing the fines with a binding agent and water to produce an agglomerate, drying the agglomerate and sintering it.
• the agglomerated particles so formed are resistant to degradation forces associated with transport and handling.
• the agglomerated particles are also resistant to the physical and chemical degradation forces and temperatures associated with chlorination processing including fluidised bed reductive chlorination processing.
• the agglomerated particles may be manufactured to fall within a preferred size range to suit the dynamic requirements of fluidised bed reductive chlorination processing for example between 100 - 500 um, more preferably from approximately 150 - 250 pti. If particles fall below this range they may be entrained in the gas stream and therefore lost to the reaction. If particles fall above this range they may cease to be buoyant within the fluidised bed and form an inactive layer at the bottom of the reactor.
• the titanium-containing particles may be of any suitable titanium-containing mineral or minerals.
• the titanium-containing minerals may be natural or synthetic in origin.
• the titanium-containing mineral may be a detrital mineral.
• the titanium may be present in the titanium-containing minerals in the form of titanium dioxide.
• the titanium dioxide content of the titanium-containing minerals may be approximately 85% by weight or greater.
• a preferred titanium dioxide containing source is a deposit which includes any of the minerals rutile, anatase and leucoxene.
• the titanium-containing minerals may be subjected to initial concentration processing after extraction. Initial concentration processing may increase the average titanium dioxide content for example to approximately 90% by weight or above.
• One titanium-containing mineral deposit at Horsham, Victoria, Australia of this type is further characterized by usually fine sizing.
• the unusually fine sizing suggests that major entrainment losses may ensue from later treatment by reductive chlorination in a fluid bed.
• the titanium-containing mineral may be present in any suitable amount in the agglomerated particles.
• the titanium-containing minerals may be present in amounts of approximately 95 - 99.5% by weight based on the total weight of the sintered agglomerate.
• the amount of water added may vary depending upon the size distribution of the original titanium-containing particles and the required size of the agglomerates.
• the amount of water may vary from approximately 5 to 15% by weight, preferably approximately 8% by weight, based on the total weight of titanium-containing particles, binder and water.
• the binder or binders for the titanium-containing particles may be of any suitable type.
• the binder for the titanium-containing particles should be such as to form agglomerates capable of withstanding the physical, chemical and thermal degradation forces in the drying and firing stages of the process.
• the binder may be an organic or inorganic binder.
• the binder may be a ceramic or glass-forming binder.
• the binder may be a carbon-free binder.
• a single binder may be used.
• a combination of two or more binders may be used to provide strength under the different operating environments of the drying and firing stages.
• Binders may contain calcium or sodium but should not result in the addition of these elements to cause problems in chlorination.
• the binder for the titanium-containing minerals may be such that it does not seriously contaminate the bound titanium-bearing particles for subsequent processing, for example in reductive chlorination * - processing.
• the binder for the titanium-containing particles may include: 1) Colloidal silica
• the amount of binder for titanium-containing particles should be sufficient to produce a competent agglomerate.
• the amount of binder should preferably not be sufficient to encapsulate the titanium-containing particles.
• a relatively low percentage of binder is preferred.
• the mixing step in the process according to the present invention may be conducted in any suitable manner. Agglomeration may be conducted in devices incorporating a rolling/tumbling action such as rotating disk or drum pelletisers or V-blenders, or in devices incorporating an impacting/shearing action such as high intensity micro-agglomerators or mixers, or in devices incorporating both actions. Agglomeration may be conducted in stages or in closed circuit with product sizing screens.
• the drying step may be conducted at elevated temperatures e.g. 75 to 150 C. The drying step is preferably carried out in such a manner as to limit the residence time o the agglomerates in this part of the process to less than 30 minutes.
• the drying step may be conducted in any suitable drying apparatus. A fluidised bed dryer or rotary dryer may be used.
• the temperature and residence time should be sufficient to produce homogeneous or heterogenous phase bonding between the particles within the agglomerates.
• the agglomerates may be heated to a temperatur of approximately 1000°C to 1500°C preferably 1200°C to 1400°C.
• the residence time of the agglomerates within the above temperature range may be for a period of approximately 5 minutes to approximately 6 hours.
• the firing step may be carried out in any of a number of suitable means, including fluidised bed, oven or kiln firing.
• the process may include the preliminary step of grinding at least a portion of the titanium-containing particle source.
• the preliminary grinding step may be utilised to improve the size control in the preparation of the agglomerates and thus provide a greater strength and density to the fired product.
• the titanium particles may be introduced into any suitable grinder. A ball mill or rod or intensive milling device may be used.
• the amount of titanium-containing feed to be ground may vary from 0. to approximately 100% by weight depending on the source and type of titanium-containing material.
• the grinding step may provide particles having an average size from approximately lum to approximately 50um.
• the sintered agglomerate may include a plurality of sintered agglomerated particles.
• the bond formed between the titanium-containing particles may include particle boundary recrystallisation, that is the boundaries of the titanium-containing particles may be physically merged.
• the bond formed between the titanium-containing particles may in addition include a bridging with a secondary phase formed by the binder.
• the sintering step may tend to reduce or eliminate the binder from the agglomerated particles.
• the initial binder may be burned off in whole or in part.
• the initial binder may be present and/or may be incorporated in whole or in part in the crystal lattice of the particles.
• the V-blender rotated at a speed of 40 rpm. Water was then introduced into the mixture through an intensifier bar rotating within the blender shell at a speed of 1500 - 3000 rpm. The intensifier bar served both to shear the solids and to spray the water into the charge in a finely divided form. The amount of water added was about 8% of the solids weight and the time required for its addition was about 4 minutes. A further 1 to 2 minutes mixing time was allowed fo the microagglomerates to achieve final size and compaction. The product was then discharged onto a large tray, spread out and oven dried at 80°C for 48 hours to ensure that drying was complete.
• the dried product was then sieved to a size range o 125-500pm.
• a 100 g sample of the micro agglomerates was placed on a ceramic dish and heated for 25 minutes at 1260°C.
• the sintered product was then subjected to several physical and chemical tests considered appropriate for determining its suitability as a feed material for reductive chlorination processing.
• a "strength test” was performed on the microagglomerates as follows; a microagglomerate was placed between two glass slides and weights were added until the microagglomerate first failed. Failure first occurred at greater than 1 kg (i.e., approximately 10 N) for 300 ⁇ m agglomerates. Fracture fragments were of similar size, i.e., there was little or no tendency to dusting. Calculations indicate that for the recorded strength it would be possible to store agglomerates without failure due to compressive forces in piles or storage bins of approximately 50 m in height.
• a more quantitative and reproducible test for resistance to abrasion was determined by violently shaking one gram of a closely sized fraction of microagglomerates (-335 +250pm for 5 minutes in a cylindrical tube 18mm i.d. and 50mm long with 3 ceramic balls 8mm in diameter. During this test, the material was subjected to both impact and attrition. The average particle diameter after this test had reduced from 303pm to 170pm. This compares with the performance of a similar sample of the original leucoxene material which reduced to 220pm.
• microagglomerates represent an industrially useful material from the points of view of storage and transport.
• Small samples (lOg) of microagglomerates were subjected to fluidised bed chlorination tests in a laboratory scale reactor at temperatures, between 950 and 1100°C. The results showed that at greater than 50% completion of chlorination:
• the fluidisation performance of the microagglomerates was measured as a function of size and compared with the behaviour of theoretical spheres, petroleum coke and beach sand leucoxene.
• the results, plotted as practical minimum fluidisation velocity in room temperature air against average particle diameter, are presented in Fig. 1. These results suggest higher than expected minimum fluidisation velocities at smaller particle diameters and lower than expected minimum fluidisation velocities at larger particle diameters. This behaviour may be explained partly by size distribution effects and partly by density and surface shape and roughness effects. It suggests that the chlorination process may be able to accept significantly larger agglomerate particles than is the case with conventional feeds, so affording the possibility of improved process recoveries.
• EXAMPLE 2 Approximately 10 kg of ground leucoxene were agglomerated and dried in the manner described in Example 1. The microagglomerates were fed to a small pilot scale fluidised bed furnace in which the bed temperature was maintained at a temperature of 1260°C. The operating parameters of the f rnace were: bed diameter 30 cm windbox temperature 1000°C windbox fuel LPG bed fuel coconut husk char superficial gas velocity 71 cm sec " in fluidised bed agglomerate feed rate 22 kg hr ⁇ In order to control both temperature and superficial gas velocity within the bed at the desired range it was found necessary on this small equipment to enrich the inlet air with oxygen.
• the average residence time of the material within the bed was approximately 20 minutes.
• the amount of bed material lost by entrainment in the off-gas was estimated at 4.5%.
• the size distributions of feed, product and carryover material were as shown in Figure 2.
• the product was subjected to the abrasion-attrition test described in Example 1. The result showed a reduction in average particle size from 303pm to 190pm.
• “Flexomix” agglomerator manufactured by Schugi Process Engineers of Lelystad, Netherlands at a solids feed rate of 840 kg per hour. Bentonite was premixed with the feed at 1% addition and lignosulphonate was added as a 33% solution at 2.8 kg solids per hour. Moisture input in addition to lignosulphonate addition was 1 L min After continuous passage through the agglomerator and a fluid bed drying unit 67.5% of the product was in the size range +125 -500pm. Product coarser than 125pm diameter was collected for subsequent kiln based firing. Firing of the agglomerates was conducted in a 3.6m long 0.23m internal diameter counter current oil fired rotary kiln.
• the agglomerate residence time in the 1260°C high temperature zone was approximately 20 minutes.
• a total of 60 kg of agglomerates was fired in the kiln at a feed rate of 16.2 kg per hour.
• Fine material in the feed and degraded material formed in firing were swept from the kiln by combustion gases, providing 69% recovery of feed in kiln products. Feed and product particle size distributions are recorded below:
• the blender was fed with ground leucoxene at 0.6 tonnes per hour with addition of bentonite at 6 kg per hour and organic binder (PVA) at 1.5 kg per hour.
• Moisture was added as 10% of feed weight via sprays mounted on the shaft of a set of high speed rotating blades within the agglomeration chamber.
• Mineral residence time in the agglomerator was approximately 20 minutes.
• the agglomerated product was dried in a tubular dryer to a maximum temperature of 80 C.
• the particle size distribution of the dried product is indicated below:
• the dried agglomerated product was fed at 73 kg per hour to a 1250 C fluidised bed firing unit.
• the fluidised bed firing unit had a diameter of.0.46m and a height (above the distributor plate) of 0.56m.
• the fluidising gas was the air rich combustion product of propane. Distillate was atomised into the base of the fluidised bed to provide additional heat by combustion with the oxygen remaining in the fluidising gases. Average residence time of the agglomerates in the fluidised bed was approximately 60 minutes. Fine material present in the feed and generated in fluidised bed firing was entrained in exiting combustion gases and removed via a hot cyclone. Only 17% of the feed reported in this "blowover" stream.

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• 1989
  • 1989-07-25 AU AU39897/89A patent/AU626155B2/en not_active Expired
  • 1989-07-25 DE DE68915446T patent/DE68915446T2/de not_active Expired - Fee Related
  • 1989-07-25 WO PCT/AU1989/000314 patent/WO1990001072A1/en unknown
  • 1989-07-25 KR KR1019900700646A patent/KR900702059A/ko not_active Application Discontinuation
  • 1989-07-25 WO PCT/AU1989/000315 patent/WO1990001073A1/en active IP Right Grant
  • 1989-07-25 EP EP89908683A patent/EP0426731B1/en not_active Expired - Lifetime
  • 1989-07-25 AT AT89908683T patent/ATE105873T1/de not_active IP Right Cessation
  • 1989-07-25 KR KR1019900700645A patent/KR0148343B1/ko not_active IP Right Cessation
  • 1989-07-25 AU AU39898/89A patent/AU626191B2/en not_active Ceased
  • 1989-07-25 RU SU894894816A patent/RU2080396C1/ru active
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• 1991
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