WO2015176166A1 - Procédés de décomposition de chlorure d'aluminium en alumine - Google Patents

Procédés de décomposition de chlorure d'aluminium en alumine Download PDF

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Publication number
WO2015176166A1
WO2015176166A1 PCT/CA2015/000334 CA2015000334W WO2015176166A1 WO 2015176166 A1 WO2015176166 A1 WO 2015176166A1 CA 2015000334 W CA2015000334 W CA 2015000334W WO 2015176166 A1 WO2015176166 A1 WO 2015176166A1
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Prior art keywords
steam
aici
alumina
temperature
amount
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PCT/CA2015/000334
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English (en)
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Ebrahim ALIZADEH
Jonathan BOUFFARD
Hubert Dumont
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Orbite Technologies Inc.
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Publication of WO2015176166A1 publication Critical patent/WO2015176166A1/fr

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    • 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
    • C01F7/48—Halides, with or without other cations besides aluminium
    • C01F7/56—Chlorides
    • 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
    • C01F7/30—Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
    • C01F7/306—Thermal decomposition of hydrated chlorides, e.g. of aluminium trichloride hexahydrate
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
    • C01P2002/88—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by thermal analysis data, e.g. TGA, DTA, DSC
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity

Definitions

  • the present disclosure relates to improvements in the field of chemistry applied to the production of alumina. For example, it relates to processes for the production of alumina via the decomposition of aluminum chloride.
  • Alumina is the raw material used for the production of aluminum metal usually by the Hall-Heroult process.
  • Most commercial alumina is produced through a Bayer type process. That approach mixes the bauxite with a hot concentrated NaOH solution, which dissolves alumina, silica and other impurities.
  • the Bayer process produces gibbsite (AI(OH) 3 ) that can be thermally converted into alumina. Due to the presence of NaOH in the process, the alumina end product contains a significant amount of Na 2 0 (0.3-0.4%wt). Other oxides are also present but in smaller quantities. This level of impurities is not useful for the modern applications of alumina, for example in making synthetic sapphire for use in LED lighting, Li-ion battery separators and display panels for example, for home, electronics and automotive markets.
  • a process intermediate product in the form of a concentrated aluminum chloride solution, is crystallized to produce aluminum chloride hexahydrate (ACH) crystals.
  • the ACH can be thermally decomposed to produce ⁇ -alumina that once calcined is converted into corundum ( ⁇ -alumina) at a higher temperature (about 1200°C).
  • ⁇ -alumina corundum
  • the transformation stages into ⁇ -alumina and a-alumina are respectively called decomposition and calcination.
  • the decomposition reaction produces a gaseous mixture of HCI and water.
  • Materials that can resist the high temperature and highly corrosive nature of the generated gas may be used for equipment construction. Such choice of material can, for example, cause a direct increase of the equipment capital cost.
  • the type of gas that occupies the reaction chamber may have an influence on the reaction kinetics.
  • the environment is occupied with a nitrogen-rich combustion flue gas and minor contents of HCI as well as water that are derived from fuel combustion and the decomposition reaction.
  • inert gases such as nitrogen are used to sweep the decomposition gases
  • the chlorine content left in the decomposed material is as high as about 1 .4 to about 3.8 wt% at a temperature of about 600 °C to about 900 °C for a relatively long residence time of two hours.
  • the hydrogen chloride concentration in the gas phase may be lowered by the addition of the combustion product.
  • a process for decomposing AICl3*6H 2 0 into ⁇ - ⁇ 2 03 comprising heating the AICI 3 *6H 2 0 at a temperature of about 600°C to about 900°C in the presence of steam and optionally at least one gas, under conditions suitable to obtain the ⁇ - ⁇ 2 03.
  • a process for decomposing AICl3*6H 2 0 into ⁇ - ⁇ 2 03 comprising heating the AICI 3 *6H 2 0 at a temperature of about 600°C to about 850°C in the presence of steam and optionally at least one gas, under conditions suitable to obtain the ⁇ - ⁇ 2 0 3 .
  • a process for decomposing AICl3'6H 2 0 into ⁇ - ⁇ 2 0 3 comprising heating the AICI 3 *6H 2 0 at a temperature of about 600°C to about 800°C in the presence of steam and optionally at least one gas, under conditions suitable to obtain the ⁇ - ⁇ 2 0 3 .
  • a process for decomposing AiC *6H 2 0 into ⁇ - ⁇ 2 0 3 comprising heating the AICI 3 « 6H 2 0 at a temperature of about 600°C to about 800°C in the presence of steam and optionally at least one gas chosen from air, argon, nitrogen, carbon dioxide, hydrogen and hydrochloric acid, under conditions suitable to obtain the ⁇ - ⁇ 2 0 3 .
  • the processes of the present disclosure may improve the process of alumina production from thermal decomposition of ACH crystals in comparison to known processes for preparing alumina, for example in that: ⁇ -alumina is obtained at a lower temperature (about 600°C to about 800°C) with steam instead of about 900°C as for conventional alumina processes with an air medium. Having the reactor at a lower temperature may lead to less energy consumption.
  • the content of residual chlorine drops to less than few hundred ppm. Therefore, subsequent equipment may not, for example require a special design regarding construction material when corrosion is taken into account.
  • complete decomposition in a single reactor rather than two consectuvie ones may, for example, eliminate the necessity of a second decomposer and therefore decrease the capital cost to design, manufacture and operate the equipment.
  • the processes can be carried out in a single step or in more than one step.
  • the decomposition can be carried out in two different recators or decomposers or in a plurality thereof.
  • the off gas mainly contains hydrogen chloride and steam that may, for example be treated easily in the scrubbing plant since both gases are easily condensed/absorbed by water.
  • the presence of inert gases or exhaust gas reduces the concentration of hydrogen chloride and steam in the off gas and the efficiency of the absorption process may, for example be decreased due to mass transfer limitations.
  • the presence of a large quantity of exhaust gas may also, for example use more cooling agent in the scrubbing system.
  • off gases containing chlorine for example in the form of HCI
  • HCI hydrogen chloride
  • off gases containing chlorine can be condensed/absorbed and reused in the alumina preparation plant either at the leaching/digestion or at ACH precipitation, crystallization, or preparation thereof.
  • Figure 1 is a plot showing the results of differential scanning calorimetry as a function of temperature for ACH crystals heated under an argon atmosphere at a heating rate of 10°C/min according to another comparative example for the processes of the present disclosure in comparison to ACH crystals heated under a steam atmosphere at a heating rate of 10°C/min according to an example of the processes of the present disclosure;
  • Figure 2 is a plot showing the results of thermogravimetric analysis as a function of temperature for ACH crystals heated under an argon atmosphere at a heating rate of 10°C/min according to another comparative example for the processes of the present disclosure in comparison to ACH crystals heated under a steam atmosphere at a heating rate of 10°C/min according to an example of the processes of the present disclosure;
  • Figure 3 is a plot showing an enlarged verion of the area indicated with a circle in the results of thermogravimetric analysis shown in Figure 2;
  • Figure 4 is a plot showing the chlorine content (wt%) as a function of temperature (°C) for samples of amorphous alumina heated at various temperatures while sweeping with air or nitrogen gas according to another comparative example for the processes of the present disclosure compared to samples of amorphous alumina heated at various temperatures while sweeping with steam or a mixture of steam and air according to another example of the processes of the present disclosure;
  • Figure 5 is a plot showing the chlorine content (wt%) and morphology as a function of temperature (°C) for samples of amorphous alumina heated at various temperatures while sweeping with air or nitrogen gas according to another comparative example for the processes of the present disclosure compared to samples of amorphous alumina heated at various temperatures while sweeping with steam according to another example of the processes of the present disclosure; and
  • Figure 6 is a plot showing the results of differential scanning calorimetry as a function of temperature for ACH crystals heated under an argon atmosphere at a heating rate of 10°C/min according to another comparative example for the processes of the present disclosure in comparison to ACH crystals heated under an environment comprising 6 % of steam in argon at a heating rate of 10°C/min according to an example of the processes of the present disclosure.
  • suitable means that the selection of the particular conditions would depend on the specific manipulation or operation to be performed, but the selection would be well within the skill of a person trained in the art. All processes described herein are to be conducted under conditions sufficient to provide the desired product quality. A person skilled in the art would understand that all reaction conditions, including, when applicable, for example, reaction time, reaction temperature, reaction pressure, reactant ratio, flow rate, reactant purity, and the type of reactor used can be varied to optimize the yield of the desired product and it is within their skill to do so.
  • Smelter grade alumina refers to a grade of alumina that may be useful for processes for preparing aluminum metal.
  • Smelter grade alumina typically comprises, for example, ⁇ - ⁇ 2 0 3 in an amount of less than about 5 wt%, based on the total weight of the smelter grade alumina.
  • high purity alumina or “HPA” as used herein refer to a grade of alumina that comprises alumina in an amount of 99 wt% or greater, based on the total weight of the high purity alumina.
  • transition alumina refers to a polymorphic form of alumina other than a-alumina.
  • the transition alumina can be ⁇ - ⁇ 2 0 3 , ⁇ - ⁇ 2 0 3 , ⁇ - ⁇ 2 0 3 , ⁇ - ⁇ 2 0 3 , ⁇ - ⁇ 2 0 3 , ⁇ - ⁇ 2 0 3 or combinations thereof.
  • amorphous alumina refers to a non-crystalline alumina that lacks the long-range order characteristic of a crystal.
  • the AICI 3 *6H 2 0 may be heated optionally in the presence of air.
  • the air may be delivered to a reaction chamber in which the AICI 3 « 6H 2 0 is heated via an air stream.
  • AICI 3 » 6H 2 0 crystals may contain organics, for example, organics derived from an ore used to prepare the AICI 3 '6H 2 0 crystals.
  • the optional air may be useful to oxidize such organic molecules.
  • the optional air may also be used to dilute the steam concentration and thereby may inhibit or prevent the condensation of steam at an inlet and/or an outlet of the reactor.
  • the relative concentration of air and steam may, for example, alter other conditions useful for the decomposition reaction. For example, a process wherein higher amounts of air are used to dilute the steam will typically use higher temperatures and/or longer residence times.
  • the at least one gas can be chosen from air, argon, nitrogen, carbon dioxide, hydrogen and hydrochloric acid.
  • the steam can be present in an amount that is at least a catalytic amount.
  • the steam can be present in an amount of at least about 5 wt%.
  • the steam can be present in an amount of at least about 6 wt%.
  • the steam can be present in an amount of at least about 10 wt%.
  • the steam can be present in an amount of at least about 15 wt%.
  • the steam can be present in an amount of at least about 25 wt%.
  • the steam can be present in an amount of at least about 35 wt%.
  • the steam can be present in an amount of at least about 45 wt%.
  • the steam can be present in an amount of at least about 55 wt%.
  • the steam can be present in an amount of at least about 65 wt%.
  • the steam can be present in an amount of at least about 70 wt%.
  • the steam can be present in an amount of at least about 75 wt%.
  • the steam can be present in an amount of at least about 80 wt%.
  • the steam can be present in an amount of at least about 85 wt%.
  • the steam can be present in an amount of at least about 90 wt%.
  • the steam can be present in an amount of at least about 95 wt%.
  • the steam can be present in an amount of about 5 wt% to about 95 %.
  • the AICI 3 » 6H 2 0 can be heated in the presence of steam and the at least one gas.
  • the steam can be present in an amount of about 80 wt% to about 90 wt% and the at least one gas can be present in an amount of about 10 wt% to about 20 wt%, based on the total weight of the steam and the at the least one gas .
  • the steam can be present in an amount of about 82 wt% to about 88 wt% and the at least one gas can be present in an amount of about 12 wt% to about 18 wt%, based on the total weight of the steam and the at least one gas .
  • the steam can be present in an amount of about 85 wt% and the at least one gas can be present in an amount of about 15 wt%, based on the total weight of the at least one gas .
  • the AICI 3 » 6H 2 0 can be heated at a temperature of about 650°C to about 800°C.
  • the AICI 3 « 6H 2 0 can be heated at a temperature of about 700°C to about 800°C.
  • the AICI 3 « 6H 2 0 can be heated at a temperature of about 700°C to about 750°C.
  • the AICI 3 '6H 2 0 can be heated at a temperature of about 700°C.
  • the AICI 3 « 6H 2 0 can be heated at the temperature for a time of less than about 5 hours.
  • the ⁇ 3 ⁇ 6 ⁇ 2 0 can be heated at the temperature for a time of less than about 4 hours.
  • the AICI 3 '6H 2 0 can be heated at the temperature for a time of less than about 3 hours.
  • the AICI 3 *6H 2 0 can be heated at the temperature for a time of less than about 2 hours.
  • the AICI 3 « 6H 2 0 can be heated at the temperature for a time of less than about 1 hour.
  • the AICI 3 « 6H 2 0 can be heated at the temperature for a time of less than about 45 minutes.
  • the AICI 3 « 6H 2 0 can be heated at the temperature for a time of less than about 40 minutes.
  • the AICI 3 « 6H 2 0 can be heated at the temperature for a time of less than about 30 minutes.
  • the steam can be provided at a rate of from about
  • the steam can be provided at a rate of from about 0.001 grams to about 2 grams of steam per gram of AICI 3 '6H 2 0, per minute.
  • the steam can be provided at a rate of from about 0.01 grams to about 2 grams of steam per gram of AICI 3 *6H 2 0, per minute.
  • the steam can be provided at a rate of from about 0.05 grams to about 1 gram of steam per gram of AICI 3 *6H 2 0, per minute.
  • the steam can be provided at a rate of from about 0.05 grams to about 0.5 grams of steam per gram of AICI 3 *6H 2 0, per minute.
  • the steam can be introduced at a ratio of mass of steam introduced to mass of ⁇ - ⁇ 2 0 3 obtained of about 0.001 :1 to about 100:1.
  • the steam can be introduced at a ratio of mass of steam introduced to mass of ⁇ - ⁇ 2 0 3 obtained of about 0.01 :1 to about 100:1.
  • the steam can be introduced at a ratio of mass of steam introduced to mass of ⁇ - ⁇ 2 0 3 obtained of about 0.1 :1 to about 100:1.
  • the steam can be introduced at a ratio of mass of steam introduced to mass of ⁇ - ⁇ 2 0 3 obtained of about 1 :1 to about 50:1.
  • the steam can be introduced at a ratio of mass of steam introduced to mass of ⁇ - ⁇ 2 0 3 obtained of about 10:1 to about 50:1.
  • the steam can be introduced at a ratio of mass of steam introduced to mass of ⁇ - Al 2 0 3 obtained of about 10:1 to about 30:1 .
  • the heating of the AICI 3 « 6H 2 0 at the temperature can be carried out in a chamber in the presence of the steam and optionally the at least one gas, and the steam and optionally the at least one gascan be released from the chamber after the ⁇ - ⁇ 2 0 3 is obtained.
  • the heating of the AICI 3 « 6H 2 0 at the temperature can be carried out in a chamber, the steam and optionally the at least one gas can be introduced into the chamber prior to the heating at the temperature, and the steam and optionally the at least one gas can be released from the chamber after the ⁇ - ⁇ 2 0 3 is obtained.
  • the decomposition of the AICI 3 « 6H 2 0 into the ⁇ - ⁇ 2 0 3 can be carried out in the presence of superheated steam.
  • the steam can be introduced into the process as saturated steam, water or a mixture thereof.
  • heating the reactor indirectly will typically lead to higher concentrations of HCI in the off gas and may therefore reduce contamination of the product ⁇ - ⁇ 2 03.
  • it is also useful to heat the reactor directly for example, where it is not as important that the product ⁇ - ⁇ 2 0 3 has low amounts of contamination.
  • the AICI 3 *6H 2 0 can be heated indirectly.
  • the AICI 3 *6H 2 0 can be heated directly.
  • the decomposition of AICI 3 '6H 2 0 into ⁇ - ⁇ 2 0 3 can be carried out in a single heating step in a single reactor. This may, for example, decrease capital cost for design and manufacture.
  • the decomposition of the AICI 3 « 6H 2 0 to the ⁇ - ⁇ 2 0 3 can be carried out in a single step.
  • the thermal decomposition of AICI 3 « 6H 2 0 to obtain ⁇ - ⁇ 2 0 3 can be carried out in any type of reactor that can provide suitable conditions for heating the AICI 3 « 6H 2 0 at a desired temperature, for example a temperature of about 600°C to about 800°C, in the presence of steam and optionally the at least one gas to obtain the ⁇ - Al 2 0 3 .
  • a desired temperature for example a temperature of about 600°C to about 800°C
  • steam and optionally the at least one gas to obtain the ⁇ - Al 2 0 3 can be carried out in any type of reactor that can provide suitable conditions for heating the AICI 3 « 6H 2 0 at a desired temperature, for example a temperature of about 600°C to about 800°C, in the presence of steam and optionally the at least one gas to obtain the ⁇ - Al 2 0 3 .
  • a variety of known reactors can provide suitable conditions, the selection of which for a particular process can be made by a person skilled in the art.
  • the process can be carried out in a fluidized bed reactor.
  • the process can be carried out in a rotary kiln reactor.
  • the process can be carried out in a pendulum kiln reactor.
  • the process can be carried out in a tubular oven.
  • the AICI 3 '6H 2 0 can be derived from an aluminum- containing-material.
  • the aluminum-containing-material can be SGA, ACH, aluminum, red mud, fly ashes etc.
  • the AICI 3 « 6H 2 0 can be derived from an aluminum- containing ore.
  • the aluminum-containing ore can be a silica-rich, aluminum-containing ore.
  • the aluminum-containing ore can be an aluminosilicate ore.
  • the AICI 3 '6H 2 0 can be derived from the aluminum-containing ore by an acid-based process.
  • the AICI 3 « 6H 2 0 can be obtained by dissolving of aluminum, alumina or aluminum hydoxide in HCI.
  • the AICl3*6H 2 0 can have a particle size distribution D50 of about 100 ⁇ to about 1000 pm or of about 100 pm to about 5000 ⁇ .
  • the AICl3'6H 2 0 can have a particle size distribution D50 of about 200 ⁇ to about 800 pm.
  • the AICI 3 » 6H 2 0 can have a particle size distribution D50 of about 300 pm to about 700 pm.ln the studies of the present disclosure, heating AICI 3 *6H 2 0 at temperatures of about 600°C to about 800°C in the presence of steam and optionally the at least one gas was found to result in the production of ⁇ - ⁇ 2 0 3 having a significantly lower residual chlorine content than the ⁇ - ⁇ 2 0 3 obtained by heating AICI 3 *6H 2 0 at this temperature range in the presence of the at least one gas (without addition of steam) or nitrogen.
  • the ⁇ - ⁇ 2 0 3 having a lower level of impurities may be useful in processes for producing smelter grade alumina and processes for producing high purity alumina, as well as fused aluminas and specialty aluminas.
  • the ⁇ - ⁇ 2 0 3 can contain less than about 1500 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 can contain less than about 1000 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 can contain less than about 750 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 can contain less than about 500 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 can contain less than about 400 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 can contain less than about 200 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 can contain less than about 100 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 can contain less than 50 ppm by weight chlorine.
  • the ⁇ - ⁇ 2 0 3 obtained from the processes of the present disclosure may be suitable for various uses, for example, uses wherein a low residual chlorine content is useful.
  • the ⁇ - ⁇ 2 03 can be suitable for use in a process for preparing smelter grade alumina (SGA).
  • the ⁇ - ⁇ 2 0 3 can be smelter grade alumina (SGA).
  • the ⁇ - ⁇ 2 0 3 can be suitable for use in a process for calcining the ⁇ - ⁇ 2 0 3 to obtain high purity alumina (HPA).
  • HPA high purity alumina
  • the ⁇ - ⁇ 2 0 3 can also be suitable for use in a process for converting the ⁇ - ⁇ 2 0 3 to obtain speciality aluminas or fused aluminas.
  • the off gases released by the processes of the present disclosure mainly comprise hydrogen chloride and steam.
  • the off gases can be recycled and reused in the aluminum chlorides extraction process and/or the AICI 3 .6H 2 0 crystals extraction and purification process.
  • off gases containing chlorine for example in the form of HCI
  • the process can release an off gas comprising hydrogen chloride and steam.
  • the composition of the off gas can be substantially hydrogen chloride and steam.
  • hydrogen chloride gas and steam are easily condensed and/or absorbed by water.
  • the process can further comprise treating the off gas in a scrubbing unit, wherein in the scrubbing unit, the hydrogen chloride and steam are condensed and/or absorbed by water and/or recycling and reusing the off gas in the aluminum chloride extraction process and/or the AICI3.6H2O crystals extraction and purification process.
  • off gases containing chlorine for example in the form of HCI
  • the processes of the present disclosure can be useful for preparing SGA.
  • the processes of the present disclosure can further comprise treating the ⁇ - ⁇ 2 0 3 in order to obtain HPA, fused alumina, transition alumina, tabular alumina, calcined alumina, ultra-pure alumina or specialty alumina.
  • treatments can comprise, for example, heating (such as calcination, plasma torch treatment), forming (such as pressure, compacting, rolling, grinding, compressing, spheronization, peptization, densification).
  • fused alumina and and specialty alumina can be used for various applications.
  • ICP-MS inductively coupled plasma mass spectrometry
  • the residence time at the above temperatures depended on the temperature.
  • the samples were heated at a rate of 240°C/hour until the desired temperature was reached, the temperature was substantially maintained at this temperature for the relevant time then cooled at a rate of 180°C/hour until room temperature was reached.
  • residence time at 500°C was about 6 hours
  • residence time at 600°C was about 5.5 hours
  • residence time at 700°C was about 5 hours
  • residence time at 800°C was about 4 hours.
  • the reaction temperature can be decreased as low as 600°C.
  • the reaction at 600°C takes a long time and, therefore, it is useful to carry out the process at >700°C.
  • the content of residual chlorine in the alumina produced in the process with a steam environment is significantly smaller than the residual chlorine content of the alumina produced in the processes with an air or nitrogen environment.
  • the off gas contains a negligible amount of inert gas which may simplify the design of a scrubbing section associated to the decomposer or allow for the off gas to be recycled and reused in the aluminum chloride extraction process and/or the AICI 3 .6H 2 0 crystals extraction and purification process.
  • off gases containing chlorine for example in the form of HCI
  • the complete decomposition occurs at reduced temperatures (as low as 600°C compared to 900°C typically) and unreacted ACH content decreases to less than a few hundred ppm. As the chlorine content drops to a very small level, it may, for example, reduce the potential corrosion which may occur in subsequent equipment.
  • known processes for the preparation of alumina may comprise the decomposition of ACH crystals carried out in the presence of other gases such as air, hydrogen or nitrogen.
  • gases such as air, hydrogen or nitrogen.
  • the use of hydrogen may, for example increase the operational cost due to consumption of hydrogen as well as treatment of the off gas. Its usage is also, for example associated with stricter codes and standards for the process and equipment design which may, for example increase the capital cost and/or the potential safety issues.
  • the decomposition reaction in an environment of air or nitrogen occurs at higher temperatures (at least about 800°C) and the content of residual chlorine in the product may, for example be relatively higher than the chlorine content in alumina which is produced in the presence of steam.
  • alumina which contains a low content of residual chlorine
  • the reaction uses very high temperatures (about 900-1000°C).
  • a high level of residual chlorine content may, for example result in corrosion inside the subsequent equipment over a long time period if the process is operated at high temperatures (for example inside a calciner to obtain corundum).
  • Residual chlorine is also problematic, for example when the alumina is used in the Hall process for aluminum metal production.
  • a low chlorine content may, for example be desired for high quality alumina refractories, fused alumina or other such uses of alumina.
  • ACH crystals were analyzed by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC) under an argon atmosphere, heated at a rate of 10.0°C per minute as compared to a steam environment under the same conditions.
  • TGA thermogravimetric analysis
  • DSC differential scanning calorimetry
  • ACH crystals were also analyzed by TGA under a steam atmosphere, heating at a rate of 10°C/minute.
  • Figure 2 shows a comparison between the TGA curves for ACH crystals heated under the steam atmosphere to ACH crystals heated under an argon atmosphere under similar conditions.
  • Figure 35 shows an enlarged version of the area indicated with a circle in Figure 2.
  • the ACH crystals heated under an argon atmosphere show additional weight loss (about 3-4 wt%) in a temperature region wherein the ACH crystals heated under a steam atmosphere do not show weight loss.
  • the weight loss in this region of the ACH crystals heated under an argon atmosphere is chlorine which was present before loss from the sample in the form of polyaluminum chlorides.
  • the end of the decomposition for the ACH crystals heated under a steam atmosphere was at about 750°C whereas the end of the decomposition for the ACH crystals heated under an argon atmosphere was at about 1200°C.
  • the experiments also showed that under a steam atmosphere the "drastic loss of mass" during the transition from the ⁇ - ⁇ 2 0 3 phase is not observed (see the loss of residual chlorine when decomposition is carried out under an argon atmosphere).
  • FIG. 4 shows various results obatined while sweeping with nitrogen gas, air, steam or a combination of steam and air. Steam has been introduced at a rate of 3.62 ⁇ 0.45 grams/minute.
  • FIG 4 shows the results for the experiments with nitrogen gas.
  • the amorphous alumina used had a chlorine content of about 3.8 wt%. After the amorphous alumina was heated for the high residence time used for the temperature of 500°C there was still between 3-4 wt% chlorine present in the sample. As the temperature increased, the chlorine content after heating decreased but was still significant for the temperature of 900°C. Proper granular flow may help to increase the capacity but not the chlorine content.
  • Figure 4 also shows the results for the experiments with air compared to the results of the experiments with nitrogen gas.
  • the amorphous alumina for the experiments with air had a chlorine content of about 3.5 wt%.
  • the samples heated with air had a lower chlorine content.
  • the chlorine content was 2000 ppm by weight (0.2 wt%).
  • the chlorine content was less than 150 ppm by weight.
  • Figure 4 also shows the results for the experiments with steam compared to the results of the experiments with air and nitrogen gas.
  • the amorphous alumina for the experiments with air had a chlorine content of about 3.2 wt%.
  • the samples heated with steam had a lower chlorine content.
  • the presence of steam decreases the chlorine content to 500 ppm by weight (0.05 wt%) after heating at a temperature of 600°C.
  • Figure 4 shows the results for the experiments with steam and air (air: 15 ⁇ 1 wt%) compared to the results of the experiments with air, nitrogen gas and steam (without air).
  • the samples heated with steam and air had a lower chlorine content.
  • the presence of steam and air decreases the chlorine content to 300 ppm by weight (0.03 wt%) after heating at a temperature of 600°C.
  • Figure 5 shows the results for the above-described experiments with steam compared to the results for the above-described experiments with air and nitrogen, labeled to indicate the results of crystalline structure analysis (XRD).
  • XRD crystalline structure analysis
  • ACH crystals were analyzed by differential scanning calorimetry (DSC) as described in Example 2, with the exception that the comparison was made between conditions under an argon atmosphere and conditions under an environement comprising argon and 6 % of steam.
  • DSC differential scanning calorimetry
  • the temperature for the transition to both ⁇ - ⁇ 2 0 3 and ⁇ - ⁇ 0 3 occurs at a lower temperature for the ACH crystals heated under an environment comprising 6 % os team and argon ( ⁇ - ⁇ 2 0 3 : peak at 776.5°C; ⁇ - ⁇ 2 0 3 : peak at 1169.5°C) in comparison to the ACH crystals heated under an argon atmosphere ( ⁇ - ⁇ 2 0 3 : peak at 862.3°C; ⁇ - ⁇ 2 0 3 : peak at 1243°C) at the same heating rate.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

L'invention concerne des procédés permettant de décomposer l'AlCl3•6H2O en γ-Al2O3 et consistant à chauffer l'AlCl3•6H2O à une température d'environ 600 °C à environ 800 °C en présence de vapeur et éventuellement d'au moins un gaz (par exemple choisi parmi l'air, l'argon, l'azote, le dioxyde de carbone, l'hydrogène et l'acide chlorhydrique), dans des conditions appropriées pour obtenir le γ-Al2O3. Par exemple, le γ-Al2O3 obtenu peuvent être approprié pour être utilisé dans un procédé de fusion d'aluminium ou éventuellement dans des procédés de traitement de γ-Al2O3 pour obtenir une alumine de haute pureté, une alumine fondue, une alumine de transition, une alumine tabulaire, une alumine calcinée, une alumine ultra-pure ou une alumine spéciale.
PCT/CA2015/000334 2014-05-21 2015-05-21 Procédés de décomposition de chlorure d'aluminium en alumine WO2015176166A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107265488A (zh) * 2017-07-20 2017-10-20 辽宁东大粉体工程技术有限公司 一种二步法生产γ型氧化铝的工艺装置与方法
CN113233877A (zh) * 2021-05-12 2021-08-10 中铝山东有限公司 一种煅烧α氧化铝的脱钠方法
US20220194790A1 (en) * 2019-03-29 2022-06-23 Sgl Carbon Se Hcl recovery unit

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2277037A1 (fr) * 1974-07-01 1976-01-30 Ruthner Industrieanlagen Ag Procede de fabrication d'alumine pure
US4465566A (en) * 1982-07-20 1984-08-14 Atlantic Richfield Company Method of producing anhydrous aluminum chloride from acid leach-derived ACH and the production of aluminum therefrom
US4486402A (en) * 1981-12-30 1984-12-04 Produits Chimiques Ugine Kuhlmann Process for the preparation of high purity aluminas starting from impure aluminum chloride solutions
US4560541A (en) * 1984-03-15 1985-12-24 Atlantic Richfield Company Production of low silica content, high purity alumina
GB8531481D0 (en) * 1985-12-20 1986-02-05 Laporte Industries Ltd Alumina
WO2013037054A1 (fr) * 2011-09-16 2013-03-21 Orbite Aluminae Inc. Procédés de préparation d'alumine et de divers autres produits
CA2877854A1 (fr) * 2012-08-01 2014-02-06 Aleksandr Sergeevich SENYUTA Procede de production d'alumine

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2277037A1 (fr) * 1974-07-01 1976-01-30 Ruthner Industrieanlagen Ag Procede de fabrication d'alumine pure
US4486402A (en) * 1981-12-30 1984-12-04 Produits Chimiques Ugine Kuhlmann Process for the preparation of high purity aluminas starting from impure aluminum chloride solutions
US4465566A (en) * 1982-07-20 1984-08-14 Atlantic Richfield Company Method of producing anhydrous aluminum chloride from acid leach-derived ACH and the production of aluminum therefrom
US4560541A (en) * 1984-03-15 1985-12-24 Atlantic Richfield Company Production of low silica content, high purity alumina
GB8531481D0 (en) * 1985-12-20 1986-02-05 Laporte Industries Ltd Alumina
WO2013037054A1 (fr) * 2011-09-16 2013-03-21 Orbite Aluminae Inc. Procédés de préparation d'alumine et de divers autres produits
CA2877854A1 (fr) * 2012-08-01 2014-02-06 Aleksandr Sergeevich SENYUTA Procede de production d'alumine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107265488A (zh) * 2017-07-20 2017-10-20 辽宁东大粉体工程技术有限公司 一种二步法生产γ型氧化铝的工艺装置与方法
US20220194790A1 (en) * 2019-03-29 2022-06-23 Sgl Carbon Se Hcl recovery unit
US11802046B2 (en) * 2019-03-29 2023-10-31 Sgl Carbon Se HCL recovery unit
CN113233877A (zh) * 2021-05-12 2021-08-10 中铝山东有限公司 一种煅烧α氧化铝的脱钠方法

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