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
  • C22B1/00—Preliminary treatment of ores or scrap
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
  • C22B3/12—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic alkaline solutions
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
  • C22B3/12—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic alkaline solutions
  • C22B3/14—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic alkaline solutions containing ammonia or ammonium salts
• • 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

• MINERAL PROCESSING The present invention relates to a process for producing a metal oxide product from metal-containing mineral ores.
• Metal oxides including those of the transition metals are widely used in industrial applications. These include use as alone or as components in catalysts, corrosion resistant coatings, glazes, electrically conducting coatings, pigments, cosmetics, fillers, pharmaceuticals, plastics additives, alloy precursors and phosphors.
• Such metals include Titanium (Ti), Zirconium (Zr), Hafnium (Hf), Vanadium (V), Niobium (Nb) , Tantalum (Ta) , Chromium (Cr), Molybdenum (Mo), Tungsten ( ) , Manganese (Mn), Cobalt (Co), Nickel (Ni), Copper (Cu) , Zinc (Zn), Cadmium (Cd) , Magnesium (Mg), the Rare Earths (Sc, Y and La to Yb), Thorium (Th), Uranium (U) and Lead (Pb) .
• Tungsten for example, principally occurs in nature as the minerals Scheelite and Wolframite.
• Industrial processes known in the prior art for the extraction of tungsten oxide from its ores include: (a) roasting the concentrate and digesting it in sodium carbonate under high pressures and temperatures
• Na-WO. (Na-WO.). Addition of Al and Mg sulphates removes impurities, then the Na-WO. is converted into the ammonium form by ion-exchange.
• ammonium tungstate can be calcined to produce pure WO_.
• Niobium and Tangalum usually occur together in the minerals pyrochlore, columbite, tantalite and in tin refinery slags. Processing of the Nb/Ta concentrates to the oxide forms include:
• Nb concentrates are usually converted directly to the metallic form or to a carbide by a variety of reduction methods (e.g. aluminothermic, carbo- thermic) . The products may then be burnt to the oxide form.
• reduction methods e.g. aluminothermic, carbo- thermic
• a process for producing a metal oxide product which process includes providing a metal-containing material; and a leaching composition including a source of ammonium ions; a source of carbonate ions; and water; contacting the metal-containing material with the leaching composition to form an aqueous slurry for a time sufficient such that a metal complex is produced; subjecting the metal-containing material to a size reduction step prior to, or simultaneously with, the leaching step such that the average diameter of the particles is below approximately 100 micron; and isolating a leaching solution containing the metal complex so formed.
• The. present invention may provide a general method for the extraction of various metal oxides from their ores whilst reducing or eliminating the complexities attendant to prior art processes.
• the metal oxides within the metal-containing material react with aqueous solutions of a leaching agent derived from ammonium carbonate, bicarbonate, carbamate or related compounds.
• the metal-containing material may be a mineral or mineral ore, concentrate or a processing waste or by-product, such as a slag or spent shale.
• the metal- containing material may be a metal compound, complex or other chemical combination, and be present in the material in a chemical combination such as an oxide, a silicate, sulphide, other chalcogenide, phosphate, carbonate, sulphate, borate, a mixed metal oxide or combinations of these.
• the metal-containing material may include one or more of metals selected from Groups 4, 5 and 6 of the Periodic Table, as well as other electropositive and oxophilic metals.
• the metal-containing material may include one or more of the following metals: Vanadium (V), Niobium (nb) , Tantalum (Ta) , Chromium (Cr) , Molybdenum (Mo), Tungsten (W), and the Rare Earths (Sc, Y and La to Yb) .
• the metal-containing material may additionally include metals selected from Titanium (Ti), Zirconium (Zr), Hafnium (Hf) , Manganese (Mn) , Cobalt (Co), Nickel (Ni), Copper (Cu) , Zinc (Zn), Cadmium (Cd) , Magnesium (Mg), Thorium (Th) , Uranium (U) and Lead (Pb) .
• the metal-containing material may contain varying amounts of impurities, either in solid solution or as a discrete amorphous or crystalline phase.
• the material may be converted into another phase, more reactive than the original phase, before leaching.
• the process may include a preliminary step of providing a metal-containing material, and an alkaline earth metal salt, contacting the metal-containing material with the metal salt at elevated temperatures to form an alkaline earth metallate.
• the preliminary reaction is conducted at a temperature of approximately 500°C to 1600°C, preferably approximately 750 ⁇ C to 1200°C.
• the preliminary reaction may continue for from approximately 1 to 24 hours.
• the heating step may be performed in air, in an inert gas or under a reducing atmosphere.
• the alkaline earth metal salt may be a carbonate, hydroxycarbonate, oxide or hydroxide.
• the alkaline earth metal salt may be a salt of barium or calcium, barium is preferred.
• reaction sequence may be idealised by the following chemical equation 2FeCr 2 0 4 + 4Ba(OH) 2 + 3.50 2 - 4BaCr0 4 + Fe 2 Og + 4H 2 0
• impure v " 2 ° 5 may be converted into a reactive form by reaction with barium carbonate in a reaction typified by the following idealised equation: ⁇ 2 0 5 + BaCC - BaV 2 O g + C0 2
• the particle size of the metal-containing material is selected to improve the efficiency of the process according to the present invention. Relatively small particles, generally below approximately 100 microns in average diameter and preferably below approximately 50 microns have been found to be suitable.
• the process includes the step of subjecting the metal-containing material to a size reduction step.
• the size reduction step may include a crushing and/or grinding step.
• the size reduction step may include a milling process.
• the milling process may continue over an extended period.
• the milling process may continue for from approximately 4 to 48 hours, preferably approximately 5 to 36 hours, more preferably from approximately 12 to 24 hours. Attrition milling is preferred.
• the size reduction step may be conducted prior to, or simultaneously with, the leaching step.
• the size reduction may be preferably achieved in situ by performing attrition milling and leaching simultaneously.
• the source of ammonium ions may be selected from ammonium compounds such as ammonium carbonate, ammonium bicarbonate, ammonium carbamate, or free ammonia or mixtures thereof.
• the source of carbonate ions may similarly be ammonium compounds such as ammonium carbonate, ammonium bicarbonate, ammonium carbamate, or free carbon dioxide or mixtures thereof.
• the source of ammonium ions and/or the source of carbonate ions may be provided as pure solids or as mixtures, or may be generated in situ. For example, reactions may be generated with appropriate proportions of ammonia and carbon dioxide with water.
• the source of ammonium ions and the source of carbonate ions may be present in any suitable relative amounts.
• the ratio of contained NH 3 to C0 2 may be in the range of approximately 100:1 to 1:100 by weight.
• the source of ammonium ions and the source of carbonate ions may be present in the aqueous slurry in any suitable amounts.
• the components of the leaching composition may be present in the aqueous slurry such that the concentration thereof is sufficiently high to insure rapid reaction with the metal-containing material and/or to provide at least sufficient stability of the dissolved metal complex.
• the ratio of the leaching solution to the metal-containing compound may be such that the atomic ratio of C0 2 to metal is at least approximately 1.
• the process according to the present invention may be conducted at any suitable temperatures. Temperatures in the range of 0°C to approximately 200°C, preferably 30°C to 60°C, may be used. The temperature should be preferably high enough to ensure rapid reaction with the metal-containing material, but low enough to ensure that decomposition of the dissolved metal complex is minimised.
• the process may be conducted in any suitable conventional manner, including utilising batch processing in opened or closed vessels including autoclaves or continuous processing.
• the process according to the present invention may be conducted under pressures ranging from approximately atmospheric to approximately 100 MPa above atmospheric.
• the process according to the present invention may continue for a time sufficient for a metal-containing complex to be formed.
• the leaching composition utilised in the process according to the present invention may optionally include secondary components. Secondary components which alter the thermal stability or solubility of the metal-containing complex in the aqueous solution and/or preferentially separate any metal phase formed from impurity phase or phases, may be used.
• Secondary components which may be included in the leaching solution may be selected from the free acids, salts or esters or phosphoric, phosphorous, sulphuric, sulphurous, citric, oxalic, benzoic acetic or higher carboxylic, alkyl- or arylphosphonic or -sulphonic acids or the halides (F ⁇ , Cl “ , Br “ , I ⁇ ) , pseudohalides (CN ⁇ , OCN ⁇ , SCN “ ) or combinations thereof.
• the secondary components may be added as pure solids or liquids, as diluted solutions or generated in situ, such as by reaction of free acids with NH_ or the major leachant components.
• the secondary components may be present in the leaching composition in amounts of 0 to approximately 95% by weight.
• the leaching solution containing the metal-complex may be separated from the aqueous slurry in any suitable manner.
• the metal-complex may be separated from any unreacted material or from insoluble reaction products, by filtration, flotation, centrifugation or by sedimentation.
• the residue may be recycled and reacted further with fresh leaching composition with the same or a different composition under the same or different reaction conditions as used in the original leaching reaction.
• the process may further include separating the metal leach product from the leaching solution and recycling the residue of the separation step to the leaching step.
• the process may further include contacting the residue with an alkaline earth metal salt at elevated temperatures to form an alkaline earth metal product; and recycling the alkaline earth metal product to the leaching step.
• the residue may be contacted with barium carbonate at a temperature in the range of approximately 500°C to 1600°C.
• the process of producing a metal product may further include subjecting the metal complex to a decomposition step.
• a metal-containing product may be isolated from the leaching solution by any suitable means, such as by thermal decomposition in solution or of a metal species isolated from the solution, or by removal of the unreacted leachant components. Decomposition of the metal-containing species may result in formation of free gaseous H 3 , C0 2 or other components of the original leaching solution; these may be returned to the reaction process. After removal of some or all of the soluble metal-containing species, the leaching solution may be recycled for use with a fresh charge of metal-containing material.
• BaNb 2 0 fi (10g) was attrition milled in an aqueous solution of commercial "ammonium carbonate" (80g in 200 ml water) at 18°C for 24 hours in a reaction system open to the air with partially stabilized zirconia (PSZ) balls (1 mm dia., 900g) . A light pink suspension was formed. This suspension was subsequently centrifuged and the supernatant filtered to remove any remaining solids.
• PSZ partially stabilized zirconia
• BaCroO. (20g) was attrition milled in an aqueous solution of commercial "ammonium carbonate" (80 g in 200 ml water) at 18°C for 24 hours in a reaction system open to the air with PSZ balls (1 mm dia., 900 g) .
• the resulting yellow suspension was centrifuged and the yellow supernatant liquid filtered.
• the solution was slowly allowed to evaporate to dryness at room temperature to afford a black solid, which was subsequently heated to 600°C for 1 hour giving Cr 2 0 3 as a dark green solid (characterised by powder XRD) .
• the overall yield or Cr extracted was 3%.
• BaMoC (10g) was attrition milled in an aqueous solution of commercial "ammonium carbonate" (80g in 200 ml water) at 18°C for 24 hours in a reaction system open to the air with PSZ balls (1 mm dia., 900g) .
• the resulting suspension was centrifuged and the pale green supernatant liquid filtered. This supernatant was slowly evaporated to dryness yielding (NH 4 ) g Mo_0 24 (4.4g) as a very pale green solid, characterised by powder XRD.
• NH 4 ) g Mo_0 24 4.4g
• EXAMPLE 7 Extraction of CeQ 2 from Ce Q 4 Synthetic monazite CeP0 4 .H 2 0 (10g) was attrition milled in an aqueous solution of commercial "ammonium carbonate" (60g in 150 ml water) with partially-stabilised zirconia (PSZ) balls (1 mm diam., lOOOg) at 25°C for 24 hours in a closed reaction system, the resulting suspension was centrifuged, and the supernatant filtered and evaporated to dryness. The extraction was repeated twice, and the resulting cream-colored solid was calcined in air (800°C, 4 hours) to give an off-white solid identified by XRD as CeO- (3.39g, 46% Ce extraction).
• PSZ partially-stabilised zirconia
• Example 1 The procedure of Example 1 was repeated, except that 10 g of a lateritic iron chromite concentrate from New Caledonia was used instead of Very little reaction occurred, with less 0.1 g of solid residue obtained from the extraction process.
• Example 8 The general procedure of Example 8 was repeated, except that before reaction the iron chromite (5g) was intimately mixed with Ba(OH) 2 (15g) and fired to 850°C in air for 16 h. A portion (4.2g) of the resultant material was attrition milled in an aqueous solution of commercial "ammonium carbonate" (80g in 200 ml water) with partially-stabilised zirconia (PSZ) balls (1 mm diam. , 900g) at 23 ⁇ C for 16 h in a reaction system open to the air. The brown suspension was centrifuged, and the supernatant filtered to remove any remaining solids. This filtrate was evaporated to dryness and the yellow brown solid, identified as ( H 4 2 Cr 2 0 ? by X-ray powder diffraction. Calcination of this product in air (500°C, lh) have Cr 2 0 3 (0.82g). A total proportion of 63% of the chromium in the starting concentrate was extracted in this manner.

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• 1993
  • 1993-03-31 WO PCT/AU1993/000134 patent/WO1993020249A1/en active Application Filing
  • 1993-04-01 IN IN235MA1993 patent/IN181961B/en unknown
  • 1993-04-02 ZA ZA932402A patent/ZA932402B/xx unknown

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