WO1991009978A1 - Procede de conversion des dechets en produits utiles - Google Patents
Procede de conversion des dechets en produits utiles Download PDFInfo
- Publication number
- WO1991009978A1 WO1991009978A1 PCT/CA1990/000454 CA9000454W WO9109978A1 WO 1991009978 A1 WO1991009978 A1 WO 1991009978A1 CA 9000454 W CA9000454 W CA 9000454W WO 9109978 A1 WO9109978 A1 WO 9109978A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- dross
- residue
- solution
- product
- process according
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 49
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 44
- 239000003518 caustics Substances 0.000 claims abstract description 23
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 22
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 20
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims abstract description 18
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 claims abstract description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims abstract description 4
- RREGISFBPQOLTM-UHFFFAOYSA-N alumane;trihydrate Chemical compound O.O.O.[AlH3] RREGISFBPQOLTM-UHFFFAOYSA-N 0.000 claims abstract description 4
- 150000003863 ammonium salts Chemical class 0.000 claims abstract description 3
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract 2
- -1 alkali metal aluminate Chemical class 0.000 claims abstract 2
- 239000000047 product Substances 0.000 claims description 37
- 230000029087 digestion Effects 0.000 claims description 31
- 239000007787 solid Substances 0.000 claims description 27
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 21
- 150000004645 aluminates Chemical class 0.000 claims description 19
- 229910052596 spinel Inorganic materials 0.000 claims description 11
- 239000011029 spinel Substances 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 7
- 239000007795 chemical reaction product Substances 0.000 claims description 7
- 239000011777 magnesium Substances 0.000 claims description 7
- 238000011282 treatment Methods 0.000 claims description 7
- 239000010457 zeolite Substances 0.000 claims description 7
- 229910021536 Zeolite Inorganic materials 0.000 claims description 6
- 239000003513 alkali Substances 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 6
- 229910052749 magnesium Inorganic materials 0.000 claims description 6
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 239000002253 acid Substances 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 238000000227 grinding Methods 0.000 claims description 2
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims 1
- 150000003868 ammonium compounds Chemical class 0.000 claims 1
- 239000003153 chemical reaction reagent Substances 0.000 claims 1
- 238000000926 separation method Methods 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 abstract description 15
- 229910021502 aluminium hydroxide Inorganic materials 0.000 abstract description 5
- 229910001679 gibbsite Inorganic materials 0.000 abstract description 5
- 238000004131 Bayer process Methods 0.000 abstract description 2
- 150000004767 nitrides Chemical class 0.000 abstract description 2
- 239000002243 precursor Substances 0.000 abstract description 2
- 229910018626 Al(OH) Inorganic materials 0.000 abstract 1
- 238000011221 initial treatment Methods 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 33
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 9
- 239000007788 liquid Substances 0.000 description 9
- 150000003839 salts Chemical class 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 239000000395 magnesium oxide Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 229910052593 corundum Inorganic materials 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 150000004684 trihydrates Chemical class 0.000 description 3
- 229910001845 yogo sapphire Inorganic materials 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000012263 liquid product Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000012265 solid product Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 229920000084 Gum arabic Polymers 0.000 description 1
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- MXRIRQGCELJRSN-UHFFFAOYSA-N O.O.O.[Al] Chemical compound O.O.O.[Al] MXRIRQGCELJRSN-UHFFFAOYSA-N 0.000 description 1
- 241000978776 Senegalia senegal Species 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical group [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 description 1
- 235000010489 acacia gum Nutrition 0.000 description 1
- 239000000205 acacia gum Substances 0.000 description 1
- CAVCGVPGBKGDTG-UHFFFAOYSA-N alumanylidynemethyl(alumanylidynemethylalumanylidenemethylidene)alumane Chemical compound [Al]#C[Al]=C=[Al]C#[Al] CAVCGVPGBKGDTG-UHFFFAOYSA-N 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000004581 coalescence Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- UOCIZHQMWNPGEN-UHFFFAOYSA-N dialuminum;oxygen(2-);trihydrate Chemical compound O.O.O.[O-2].[O-2].[O-2].[Al+3].[Al+3] UOCIZHQMWNPGEN-UHFFFAOYSA-N 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 229910052622 kaolinite Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011490 mineral wool Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 230000007928 solubilization Effects 0.000 description 1
- 238000005063 solubilization Methods 0.000 description 1
- 235000000346 sugar Nutrition 0.000 description 1
- 150000008163 sugars Chemical class 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
- 239000002699 waste material Substances 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
- C22B21/00—Obtaining aluminium
- C22B21/0015—Obtaining aluminium by wet processes
- C22B21/0023—Obtaining aluminium by wet processes from waste materials
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/04—Preparation of ammonia by synthesis in the gas phase
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
- C01F7/06—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process
- C01F7/0693—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process from waste-like raw materials, e.g. fly ash or Bayer calcination dust
-
- 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
- C22B21/00—Obtaining aluminium
- C22B21/0007—Preliminary treatment of ores or scrap or any other metal source
-
- 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
- C22B21/00—Obtaining aluminium
- C22B21/0038—Obtaining aluminium by other processes
- C22B21/0069—Obtaining aluminium by other processes from scrap, skimmings or any secondary source aluminium, e.g. recovery of alloy constituents
-
- 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
- This invention relates to a process for converting dross residues to useful products.
- Dross is a material which forms on the surface of molten aluminum or aluminum alloys during remelting and metal holding and handling operations when the molten metal is in contact with a reactive atmosphere.
- Dross normally consists of metal oxides and nitrides and a considerable quantity of molten free (unreacted) metal.
- dross residue dross residue
- the dumping of dross in this manner has recently come to be regarded as environmentally unacceptable because harmful chemicals may leach out of the dross into ground and surface water and thus cause widespread pollution.
- the reaction is performed in the liquid phase and under sufficient agitation to ensure particle-to-particle attrition to break the protective aluminum hydroxide film which forms about the aluminum metal contaminant particles, thereby achieving substantially complete oxidation of the aluminum metal contaminant to aluminum oxide trihydrate.
- the reaction is aimed at dross residues which still contain a relatively large amount of metallic aluminum and the reaction is concerned primarily with the reaction of this metallic component.
- An object of the present invention is thus to provide a process for treating aluminum nitride-containing dross which contains only a small or no metallic component in order to convert the dross into commercially desirable products and/or to avoid environmental pollution.
- a process for converting aluminum nitride-containing dross residue into ammonia-containing and alumina-containing products which comprises partially digesting said aluminum nitride-containing dross residue having a content of AIN of at least 5 wt % and no more than about 10 wt % of metallic aluminum with a solution having a pH of 7 or more to solubilize about 10-50 wt % of said residue and to produce an ammonia-containing reaction product, a residual solution and a solid residue; and separating said ammonia-containing reaction product from said solid residue and residual solution.
- ammonia-containing reaction product and the solid residue can be collected and optionally further treated or reacted to produce commercially valuable end products.
- the invention thus provides a way of converting aluminum nitride-containing dross residues, and especially plasma dross residues, into useful products, thus avoiding the need for disposal and producing an economic return.
- the accompanying drawing is a block diagram showing the steps of a basic form of one aspect of the process of the invention and also two optional additional treatment processes.
- the basis of the present invention is the partial digestion of the aluminum nitride-containing dross residue with a solution having a pH of 7 or more to produce at least an ammonia-containing product and a solid residue.
- the dross residue must contain at least 5 wt % of aluminum nitride and no more than 10 wt % of metallic aluminum. Drosses with larger amounts of metallic aluminum generate large quantities of unwanted hydrogen in violent reactions when digested and drosses with smaller amounts of aluminum nitride generate insufficient quantities of the desired ammonia.
- the dross residue should contain at least about 10 wt % AIN and most preferably at least about 25 wt % AIN and preferably only 2 wt% of Al or less.
- Dross treated by the plasma process indicated above has suitable contents of aluminum nitride and metallic aluminum and is the preferred type of dross residue and has the advantage (in terms of cost, convenience and wear and tear on machinery) that it can usually be used in the process of the invention without intermediate treatment steps, such as grinding to reduce the particle size; however, dross residues from other sources having the required composition may be employed, if desired.
- Dross which has been cooled rapidly to give particles having a size of 100% -20 Tyler mesh is particularly preferred. Dross which has been cooled slowly may produce sintered lumps which are not very suitable.
- the digestion should be carried out in such conditions that about 10 to 50 wt % of the residue is solubilized.
- the aluminum nitride in the dross is converted to ammonia (or an ammonium- containing product) and either a soluble product (if the pH is greater than 7) or an aluminum hydroxide precipitate (if a neutral solution is used) .
- ammonia or an ammonium- containing product
- a soluble product if the pH is greater than 7
- an aluminum hydroxide precipitate if a neutral solution is used
- This digestion step accomplishes two things; firstly
- SUBSTITUTE SHEET ammonia is produced and may be collected and liquefied or reacted with an acid to produce a soluble or insoluble salt.
- Ammonia and ammonium salts are valuable products and can be used as fertilizers and in industry.
- a useful aluminum trihydrate precipitate is formed (digestion in neutral solutions) or an aluminate solution is obtained (digestion in alkaline solutions) which can be used for the purposes outlined below.
- dross residues i.e. oxides of aluminum and other metals (e.g. Mg present in drosses from Al/Mg alloys) are generally not digested in mild conditions and remain as a solid residue. However, this solid residue can be used for commercial purposes as will be indicated later.
- a preferred additional aspect of the invention is based on the surprising discovery that digestion of dross residue in caustic alkali under harsh conditions results in the dissolution of a large component of the dross previously thought to be insoluble. In such conditions, it appears that a proportion of the aluminum and other metal oxides in the dross dissolve to form soluble aluminates.
- the digestion under caustic conditions can be carried out separately from the AIN hydrolysis step mentioned above but the two steps are usually carried out simultaneously since the AIN hydrolysis takes place under the harsh and caustic conditions as well as under the mild conditions.
- the conditions required for the digestion of otherwise insoluble fractions of the dross residue are usually as follows.
- the dross residue is normally heated in an autoclave or similar pressure reactor to a temperature up to about 325'C, preferably 50 - 300°C and usually 100 - 225°C, in the presence of a solution containing a caustic alkali (preferable NaOH for economy, although KOH or LiOH could also be used) .
- a particularly preferred solution is one containing 50 - 200 g/1 of NaOH (expressed as Na 2 C0 3 ) .
- the solutions are normally aqueous but could conceivably be organic (e.g. in alcohol or acetone) .
- Autogenous pressure is preferably generated since the reactor is closed and this pressure varies according to the reaction temperature employed.
- the autoclave is provided with a safety valve set at a pressure slightly higher than the vapour pressure of water at the intended digestion temperature.
- the vapour pressure of water is 114 psi and the safety valve is set at about 150 psi.
- the vapour pressure is 225 psi and the valve is set at 275 psi.
- Other suitable pressures are apparent from vapour pressure tables.
- the reaction mixture may be subjected to agitation to accelerate the solubilization.
- the time required for the digestion step varies according to the size of the charge of the dross residue and its composition, but the digestion is normally complete within a few hours.
- the optimum ratio of caustic solution to dross residue charge also varies, but in general it can be said that the greater the amount of the
- the aluminate solution is normally separated from the insoluble fraction e.g. by filtration with a filter press or the like or by means of any other solid/liquid separator.
- the aluminate solution and the insoluble fraction (together with any ammonia or ammonium reaction product that may have been collected) are then used, sold, converted to other products or (in the case of the insoluble fraction) even disposed of by dumping since the product is non-polluting.
- the caustic aluminate solution several treatments are possible. Firstly, the aluminate solution may be used in the conventional Bayer process as "Bayer liquor" for the production of alumina.
- so-called aluminum trihydrate (aluminum trihydroxide) can be precipitated either by cooling the caustic solution, by diluting the caustic solution with water or by a combination of the two. Seed crystals of Al(OH) 3 are generally added to the liquid to promote the precipitation of the solid.
- the trihydrate produced in this way is very white and is thus a valuable product. It appears that traces of iron and organics responsible for red and yellow hydrate products are either not present in the original dross residue (although this depends on its origin) or, if present, are not solubilized in the caustic digestion process.
- the aluminate solutions produced by the invention generally do not contain ions, such as ions of Ca, Fe, P and Mg, that slow down the precipitation of the hydrate, nor "poisons” such as sugars, gum arabic and other organics that often contaminate other hydrate products.
- the solution containing the aluminate should contain less than about 0.1 wt % of dissolved organic carbon and substantially no suspended colloidal iron in order to produce a very white trihydrate product. The solution remaining after the precipitation of the trihydrate can be recycled to the caustic digestion step, if desired.
- the aluminate in the solution resulting from the caustic digestion step can be converted to other useful chemicals, such as aluminum silicate by the addition of sodium silicate or to zeolites by the addition of Si0 2 , etc.
- the aluminate can be obtained as a solid product simply by evaporating the water from the solution.
- Other possible uses of the aluminate solution no doubt exist.
- the insoluble fraction remaining after the digestion is usually washed to remove traces of alkali and other soluble compounds and is then dried. If the solid contains hydroxide, it may be desirable to calcine the product to produce the corresponding oxide.
- the product can then be used as such as a refractory precursor or can be treated (e.g. by melting) to form a refractory product such as a rock wool.
- compositions of dross residues vary widely even when the residues come from the same type of dross treatment process, and so it is difficult to give indications of the proportions of the solid that can be solubilized. However, it is not unusual to be able to dissolve about 27% by weight of plasma dross residue by the mild hydrolysis and about 48% by weight in total following the caustic digestion step.
- the process of the invention can be operated continuously or batchwise. If preliminary hydrolysation is employed, this step is quite easily made continuous.
- the caustic digestion step can be made continuous by the use of continuous autoclaves.
- Plasma dross residue 10 and caustic sodium hydroxide solution 11 are introduced into a digester 12 to bring about partial digestion of the residue 10.
- ammonia 13 is evolved and removed from the digester 10 12 along with traces of hydrogen and methane generally formed as by-products.
- the contents of the digester 12, i.e. and aluminate solution and a solid residue, are passed to a solid/liquid separator 14 where the solid 15 is separated from the liquid 16.
- the resulting solid 15 product 15 generally contains alumina, magnesium oxide and magnesium spinel.
- the liquid product 16 contains sodium hydroxide and aluminate.
- the aluminate solution can be converted to solid A1(0H) 3 or to a zeolite.
- solid Al(OH) 3 the liquid is transferred to a digester 17 where seed crystals 18 of Al(OH) 3 are added and the liquid is cooled.
- the resulting suspension is then transferred to a solid/liquid separator 19 for removal of the A1(0H) 3 solid 20.
- the remaining solution 21 of sodium hydroxide and 5 unprecipitated aluminate is then recycled to the feed to digester 12.
- the liquid product 16 is transferred to a digester 22 to which solid Si0 2 23 is also added, preferably a source of soluble silica such as 0 silica fumes or kaolinite.
- a solid zeolite precipitate is formed and the resulting suspension is transferred to a solid/liquid separator 24.
- a solid zeolite product 25 is obtained and the remaining liquid 26 can be recirculated to the digester 12 for use in the initial digestion. 5
- the invention is described in more detail with reference to the Examples given below.
- Plasma dross residues were submitted to tests for the determination of available and extractable alumina (available alumina means the portion of dross which can be solubilized under mild alkaline conditions and extractable. alumina means the total amount of dross that can be solubilized under both mild conditions and caustic digestion at high temperature and pressure) .
- available alumina means the portion of dross which can be solubilized under mild alkaline conditions and extractable. alumina means the total amount of dross that can be solubilized under both mild conditions and caustic digestion at high temperature and pressure
- the tests involved placing the dross in a 70 ml closed bomb with a concentrated caustic alkali solution and heating the contents under pressure. The results are shown in Table 1 below.
- the invention can be applied to the utilization of dross residues which are currently discarded as waste in order to avoid environmental pollution and to create an economic return and valuable products.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
Procédé de conversion des déchets résiduels ayant une teneur en nitrure d'aliminium d'au moins 5 % en poids et une teneur en aluminium métallique ne dépassant pas 10 % en poids (en particulier les déchets résiduels de plasma) en produits utiles. Ledit précédé consiste à traiter les déchets résiduels avec une solution ayant un pH égal ou supérieur à 7, la réaction à des valeurs de pH alcalines étant: AlN + 4H2O ← + Al(OH)3 + NH4+ + OH- suivi par : Al(OH)¿3 + OH?- ← Al¿2?O?- + 2H¿2O et NH4+ + OH- ← NH¿3? $(1, 3)$ + H2. Le traitement initial des déchets résiduels peut avoir lieu dans des conditions douces afin de produire de l'ammoniaque à partir du nitrure. L'ammoniaque peut ensuite être recueilli comme produit utile ou converti en d'autres produits utiles tels que les sels d'ammonium. Dans des conditions plus sévères, par ex. une température et une pression élevées avec des alcalis caustiques, une part considérable des déchets résiduels se dissout pour former une solution d'aluminate de métal alcalin qui est elle-même un produit utile (elle peut, par ex. être utilisée dans le procédé Bayer) ou peut être convertie en d'autres produits utiles tel que le trihydrate d'aluminium. Une partie des déchets résiduels reste normalement non dissoute et peut également constituer un produit utile, par ex. un précurseur réfractaire, ou peut jetée dans un lieu de décharge puisqu'elle est non polluante.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US45796689A | 1989-12-27 | 1989-12-27 | |
US457,966 | 1989-12-27 | ||
US52939090A | 1990-05-29 | 1990-05-29 | |
US529,390 | 1990-05-29 |
Publications (1)
Publication Number | Publication Date |
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WO1991009978A1 true WO1991009978A1 (fr) | 1991-07-11 |
Family
ID=27038795
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CA1990/000454 WO1991009978A1 (fr) | 1989-12-27 | 1990-12-24 | Procede de conversion des dechets en produits utiles |
Country Status (2)
Country | Link |
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AU (1) | AU6970391A (fr) |
WO (1) | WO1991009978A1 (fr) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0576254A2 (fr) * | 1992-06-22 | 1993-12-29 | Plasma Processing Corporation | Produit réactif non-métallique récupéré de crasses |
EP0576416A1 (fr) * | 1992-06-17 | 1993-12-29 | Waagner-Biro Aktiengesellschaft | Procédé de production de l'aluminium |
WO1994012434A1 (fr) * | 1992-12-01 | 1994-06-09 | Alcan International Limited | Procede de transformation de residus de crasse d'aluminium en produits utiles |
EP1167556A2 (fr) * | 2000-06-28 | 2002-01-02 | Michael Dipl.-Ing. Dr. Techn. Kostjak | Procédé de récuparation de l'aluminium par lixiviation à partir de déchets alumineux solides |
WO2002090255A1 (fr) * | 2001-05-03 | 2002-11-14 | Wacker-Chemie Gmbh | Procede pour produire de l'energie par production et par mise en reaction de nitrure d'aluminium |
WO2011092632A3 (fr) * | 2010-01-27 | 2012-02-23 | Bumatech (Pty) Limited | Produit aggloméré contenant de l'alumine |
US20170009311A1 (en) * | 2014-02-06 | 2017-01-12 | Kabushiki Kaisha Kobe Seiko Sho ( Kobe Steel, Ltd. ) | Secondary material for steel refining |
CN109365473A (zh) * | 2018-10-17 | 2019-02-22 | 郑州中科新兴产业技术研究院 | 一种混联法实现二次铝灰脱氟及资源化的方法 |
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FR427110A (fr) * | 1910-05-19 | 1911-07-27 | Ottokar Serpek | Procédé de fabrication d'alumine pure à l'aide de nitrure d'aluminium |
GB552583A (en) * | 1941-09-19 | 1943-04-15 | Felix Singer | Extraction of aluminium oxide |
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JPS63170215A (ja) * | 1987-01-06 | 1988-07-14 | Nichijiyuu Res Center:Kk | アルミニウムドロスの造粒方法 |
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- 1990-12-24 AU AU69703/91A patent/AU6970391A/en not_active Abandoned
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FR427110A (fr) * | 1910-05-19 | 1911-07-27 | Ottokar Serpek | Procédé de fabrication d'alumine pure à l'aide de nitrure d'aluminium |
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JPS62278120A (ja) * | 1986-05-27 | 1987-12-03 | Hiroshi Matsuno | アルミニウム滓の処理方法 |
JPS63170215A (ja) * | 1987-01-06 | 1988-07-14 | Nichijiyuu Res Center:Kk | アルミニウムドロスの造粒方法 |
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Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0576416A1 (fr) * | 1992-06-17 | 1993-12-29 | Waagner-Biro Aktiengesellschaft | Procédé de production de l'aluminium |
EP0576254A2 (fr) * | 1992-06-22 | 1993-12-29 | Plasma Processing Corporation | Produit réactif non-métallique récupéré de crasses |
EP0576254A3 (fr) * | 1992-06-22 | 1994-04-06 | Plasma Processing Corp | |
AU671121B2 (en) * | 1992-06-22 | 1996-08-15 | Plasma Processing Corporation | Reactive non-metallic product recovered from dross |
WO1994012434A1 (fr) * | 1992-12-01 | 1994-06-09 | Alcan International Limited | Procede de transformation de residus de crasse d'aluminium en produits utiles |
EP1167556A3 (fr) * | 2000-06-28 | 2002-09-25 | Michael Dipl.-Ing. Dr. Techn. Kostjak | Procédé de récuparation de l'aluminium par lixiviation à partir de déchets alumineux solides |
EP1167556A2 (fr) * | 2000-06-28 | 2002-01-02 | Michael Dipl.-Ing. Dr. Techn. Kostjak | Procédé de récuparation de l'aluminium par lixiviation à partir de déchets alumineux solides |
WO2002090255A1 (fr) * | 2001-05-03 | 2002-11-14 | Wacker-Chemie Gmbh | Procede pour produire de l'energie par production et par mise en reaction de nitrure d'aluminium |
WO2011092632A3 (fr) * | 2010-01-27 | 2012-02-23 | Bumatech (Pty) Limited | Produit aggloméré contenant de l'alumine |
US9051187B2 (en) | 2010-01-27 | 2015-06-09 | Bumatech (Pty) Limited | Agglomerated alumina containing product |
US20170009311A1 (en) * | 2014-02-06 | 2017-01-12 | Kabushiki Kaisha Kobe Seiko Sho ( Kobe Steel, Ltd. ) | Secondary material for steel refining |
CN109365473A (zh) * | 2018-10-17 | 2019-02-22 | 郑州中科新兴产业技术研究院 | 一种混联法实现二次铝灰脱氟及资源化的方法 |
CN109365473B (zh) * | 2018-10-17 | 2020-03-17 | 郑州中科新兴产业技术研究院 | 一种混联法实现二次铝灰脱氟及资源化的方法 |
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