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WO1997007057A1 - Procede de production de chlorures de terres rares anhydres - Google Patents

Procede de production de chlorures de terres rares anhydres Download PDF

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Publication number
WO1997007057A1
WO1997007057A1 PCT/SE1996/001024 SE9601024W WO9707057A1 WO 1997007057 A1 WO1997007057 A1 WO 1997007057A1 SE 9601024 W SE9601024 W SE 9601024W WO 9707057 A1 WO9707057 A1 WO 9707057A1
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WIPO (PCT)
Prior art keywords
die
rare earth
reaction vessel
bed
maintained
Prior art date
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Ceased
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PCT/SE1996/001024
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English (en)
Inventor
Johan SUNDSTRÖM
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Individual
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Priority to AU67606/96A priority Critical patent/AU6760696A/en
Publication of WO1997007057A1 publication Critical patent/WO1997007057A1/fr
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Ceased legal-status Critical Current

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Classifications

    • 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
    • C01F17/00—Compounds of rare earth metals
    • C01F17/20—Compounds containing only rare earth metals as the metal element
    • C01F17/253—Halides
    • C01F17/271—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
    • C01F17/00—Compounds of rare earth metals
    • C01F17/20—Compounds containing only rare earth metals as the metal element
    • C01F17/253—Halides

Definitions

  • the present invention relates to a method for producing anhydrous rare earth chlorides, and more particularly to a method for the dehydration of hydrated rare earth chlorides.
  • rare earth metals or rare earths are denoted the elements 57 to 71 in group lllb of the periodic system, and usually element No. 21, scandium, and No. 39, yttrium, are also included. These metals are expected to be of a strongly increasing importance in the future, especially as alloying elements in intermetallic compounds. Already at present, the sales of Nd-Fe-B magnets amount to 625 million US dollars, and this amount is increasing by about 12-15 % per year.
  • Other examples of uses for rare earth metals which are or are expected to become commercially important are La-Ni hydrides for i.a. electrical storage batteries and storage of hydrogen, and Tb-Dy-Fe magnetostrictive materials.
  • the rare earth metals are also expected to become increasingly important as alloying elements in special alloys, especially then of aluminum, magnesium, titanium and high-strength steel.
  • a further use for the rare earth elements is as a doping material for optical fibres.
  • the starting material is usually a rare earth metal compound of the fluoride, oxide or chloride type.
  • electrolysis of rare earth chlorides is probably the dominating memod at present.
  • the rare earth metal chlorides have many advantageous properties which make their use as a raw material for the preparation of the metals interesting.
  • the hygroscopic properties have been regarded as a difficult problem, as they require a pretreatment step for obtaining pure and anhydrous halides.
  • rare earth chlorides are attractive raw materials both for electrolytic and metallothermic processes. However, pure and anhydrous rare earth chlorides are not easily recovered. If a cheap and environ ⁇ mentally acceptable method for the production of rare earth chlorides is developed, extraction of rare earth metal by the chloride route will become very attractive.
  • a conventionally known method practiced industrially is the direct chlorination of oxides by reaction with carbon and chlorine.
  • this method is connected with the release of environmentally unacceptable chlorinated hydrocarbons.
  • Due to the high temperature used (1100-1200°C) reactor materials are severely corroded during operation. Corrosion of reactor materials together with contamination from reactant carbon result in a deterioration of the quality and purity of the rare earth chloride product.
  • the object of the present invention is to produce pure and anhydrous rare earth chlorides with a high productivity, while minimizing the use of chlorinating reactants; minimizing the temperamre (thus minimizing energy consumption); minimizing the environmental effect and using as simple a process as possible. Another important object is to achieve process control and taking advantage of new fundamental knowledge on the dehydration kinetics of rare earth chlorides.
  • a method for producing rare earth chlorides by dehydration of hydrated rare earth chlorides characterized by the continuous or batch-wise feeding of hydrated rare earth chlorides in a fluidised bed system comprising one reactor or several reactors coupled in series; introducing dry gas com ⁇ posed of air, air/hydrogen chloride, nitrogen/hydrogen chloride, another inert gas/hydro ⁇ gen chloride or pure hydrogen chloride; at an elevated temperamre causing dehydration of hydrated rare earth chlorides and obtaining rare earth chlorides of specified maximum water content free from oxide impurities.
  • the dehydration in the terminal step may be conducted in various ways. In a batch-wise performance, which for example is preferred in the small scale production or in the alternately production of different products, the terminal step is preferably characterized by a packed bed reactor of rare earth chlorides slowly purged with gas of previously described composition. In a continuous performance, usually preferred in large scale productions, the terminal step is for example characterized by a rotary drum dryer. DESCRIPTION OF THE DRAWINGS
  • Figure 1 shows the estimated equilibrium water partial pressures for the dehy ⁇ dration of DyCl 3 • 6H 2 O.
  • Figure 2. shows the batch- wise dehydration of DyCl 3 • H 2 O of 220°C using a fluidised bed.
  • Figure 3. is a block diagram showing an example of the fluidised bed system. DESCRIPTION OF THE CHEMICAL BACKGROUND TO THE CHOICE OF GAS COMPOSITION
  • thermodynamic equations describing this ratio as a function of the temperamre have only been established in some limited cases. Therefore, in most cases (PHc ⁇ / PH2 ⁇ )eq * ⁇ as t0 be determined empirically by pilot plant tests. At higher temperamres ( >200°C) oxygen in air becomes increasingly reactive according to d e following reaction:
  • d e total reaction rate (moles of H 2 O per mole rare earth and second) may be calculated by the following equation:
  • G represent the molar gas flow rate
  • p m represents the molar bed load
  • p ⁇ o represents a value close to the equilibrium water partial pressure of the specific reaction.
  • the fluidised bed has turned out to exhibit properties which are of great advanta ⁇ ge for die dehydration process.
  • a very high gas flow can be used in a fluidising bed, making it possible to speed up me reaction rate of dehydration to a great magnitude; me turbulent mixture of gas and particles in the bed has greatly improved the access of hydrogen chloride to d e reacting particle surfaces, thereby essentially improving me ability to avoid hydrolysis; and die isothermal state, which is closely attained in the fluidised bed, has made it possible to run the process in a controlled fashion. All told, dehydration in a fluidised bed offers ie possibility to combine high productivity with obtaining of high purity rare earth chlorides. DETAILED DESCRIPTION OF THE INVENTION
  • the dehydration may be performed in one or several stages of fluidised beds judged by d e dehydration scheme.
  • Step 1 DyCl 3 • 6H 2 O ⁇ DyCl 3 • 3H 2 O + 3H 2 O
  • Step 2 DyCl 3 • 2H 2 O ⁇ DyCl 3 • H 2 O + 2H 2 O
  • Step 3 DyCl 3 • H 2 O ⁇ DyCl 3 + 2H 2 O
  • the first step of reaction was proceeding at an appreciable rate between tempera ⁇ tures of 100 to 130°C, while during die second step diis temperamre interval was between 110 and 140°C, and for the third step between 220 and 250°C.
  • the gas flow may be composed of a mixmre of dry air and hydrogen chloride, or nitrogen and hydrogen chloride, or anodier inert gas and hydrogen chloride or pure hydrogen chloride. Hydrated rare earth chlorides may be injected as a solution or preferentially as a well-defined particle fraction contaimng a minimum amount of dust.
  • the invention may be carried into practice in various ways and some embodi ⁇ ments will now be described by way of example with reference to the accompanying drawings (performed as a block diagram in figure 3) showing a system for practising a me od according to die present invention.
  • the following embodiment comprises the dehydration of rare earth chlorides to pure and anhydrous chlorides.
  • hydrated rare earth chloride feedstock is supplied at a predetermined rate from a storage tank by means of a hopper 1 to a reactor 10.
  • Dry gas preferably air
  • a minor content of hydrogen chloride necessary to avoid hydrolysis is injected dirough a heater 5 to a temperamre necessary to keep a fluidised bed 13 at d e desired temperamre.
  • bed material is by a controlled rate transferred continuously into a reactor 11.
  • a dry mixmre of an inert gas (preferably nitrogen) and hydrogen chloride having a partial pressure necessary to avoid hydrolysis is injected dirough a heater 6 to a temperamre necessary to keep a fluidised bed 14 at die desired temperature for the reaction of the last step of dehydration.
  • the terminal step is preferably characterized by a rotary drum dryer.
  • a further example of die terminal step is characterized by a packed bed tower dirough which dry gas of preferably die same composition as injected dirough d e heater 6 is slowly conducted in counter-current flow to die packed bed, which is heated from me outside walls of d e reactor to preferably d e same temperature as in the reactor 11.
  • the final product is discharged by a controlled rate from a discharge pipe 4.
  • Elutriated dust may be re-circulated (for example by CFB technique) or captured by (some) filters and recycled at an earlier stage in the process.
  • Oudet gas from 7, 8 and 9 may be washed wid respect to hydrogen chloride to produce hydrochloric acid or alternatively, it may be dried (for example through some desiccator) and recirculated. The last alternative is preferred as hydrogen chloride is diereby not consumed in the system.
  • die average molar ratio between the water of hydration and die rare earth halide is maintained between 1 and 3, and in the second reaction vessel the average molar ratio is maintained not higher than 0.2.
  • the temperature in the first reaction vessel is maintained between 50 and 200°C, preferably between 80 and 160°C, and in die second reaction vessel between 150 and 400°C, prefer ⁇ ably between 150 and 300°C.
  • me average molar ratio between die water of hydration and d e rare earth metal halide is maintained no higher than 0.2 and the temperamre in me reaction vessel is maintained between 150 and 400°C, preferably between 150 and 300°C.
  • a iospheric pressure may be used in me reaction system, but die use of elevated or reduced pressure is widiin die scope of diis invention.
  • the total gas pressure is preferably maintained between 10 kPa and 1 MPa, more preferably between atmospheric pressure and 300 kPa.
  • the inside walls of reactors and gas conduits may be of stainless steel or some other resistant material.
  • the outside walls of die fluidised bed reactors should be heated or isolated in order to minimize heat losses and avoid condensation of water vapour on the inside walls.
  • hydrated rare earth metal chlorides are fed into fluidised bed reactors and made to fluidise by injected dry gas of a composition and a temperamre of pertinence to die reaction step of dehydration. Accordingly, dehydration occurs at a high rate and rare earth chlorides of specified maximum water content and free from oxide impurities are produced from die fluidised bed system. Also, in the present invention a last step may be implemented for desired water contents below 0.05 moles water per mole formula unit, for example in which a gas having about the same composition and temperamre as in ie preceding fluidised bed reactor, is by counter-current flow slowly passed dirough a reactor, for example a packed bed reactor.
  • the inlet gas composed of dry air and 0.3 % HCl, was flowing at 30 l/min and making the powder to fluidise.
  • die inlet gas was heated to 300°C, d e temperamre of the fluidised bed rose steadily up to about 100 * C, where it converged into temperamre plateaus at about 120°C and 130°C, which were reflecting the heat consumed by die two first reaction steps of dehydration. After about 80 minutes from the start, a new rise of temperature occurred, which indicated tiiat the monohydrate had been obtained.
  • the inlet gas was then heated to 350°C and its composition was changed to mtrogen, flowing at 25 l/min, and hydrogen chloride admitted to flow wid an increasing rate witii respect to bed temperamre.
  • temperamre plateau was reached at about 225°C.
  • hydrogen chloride was admitted to flow at 5.2 l/min, making up about 17 % of total inlet gas flowing at about 30 l/min.
  • the bed temperamre was held constant for about 45 minutes, when a new rise of temperamre indicated the end of die reaction.
  • the dysprosium chloride powder dius produced had a total weight of 331 g, a water content of 0.08 moles water per mole formula unit (0.5 w%) and was free from oxide impurities. The total time of the reaction was 2 hours and 20 minutes. 8 % of the charged amount was carried away over d e freeboard.
  • the monohydrate was obtained after about 50 minutes making up a total time of 1 hour and 50 minutes for d e whole reaction.
  • the dysprosium chloride tiius produced had a total weight of 352 g, a water content of 0.09 moles per mole formula unit (0.6 w%) and was free from oxide impurities. 2 % of die charged amount was carried away over die freeboard.
  • the total time of die reaction was about 1 hour and 45 minutes.
  • the terbium chloride thus produced had a total weight of 280 g, a water content of 0.08 moles per mole formula unit (0.5 w%) and was free from oxide impurities. 2 % of the charged amount was carried away over die freeboard.
  • Example 1 was repeated except tiiat 40 g of DyCl 3 - H 2 O of particle sizes between 150 and 250 ⁇ m was used.
  • the inside diameter of die fluidised bed reaction vessel was 6 cm.
  • the inlet gas was pure hydrogen chloride and was admitted to flow at 5.2 l/min.
  • the inlet gas was heated to obtain a temperamre plateau at about 240°C during about 10 minutes
  • the total time of the reaction was about 25 minutes.
  • the dysprosium chloride dius produced had a total weight of 37 g, a water content of 0.07 moles per mole formula unit (0.5 w%) and was free from oxide impurities. 1 % of the charged amount was carried away over die freeboard.
  • a fluidised bed system composed of two reaction vessels made of Pyrex glass of 6 cm inner diameter was continuously fed witii dysprosium chloride hexahydrate powder at a rate of 2 g/min.
  • the particle sizes were between 150 and 355 ⁇ m.
  • the outiets 2 and 3 in figure 3 were kept at levels so as to maintain bed loads of 53 g in the first reactor and 40 g in the second reactor at stationary conditions.
  • a gas mixture of 99.5 % dry air and 0.5 % HCl was injected at 6 l/min and heated to keep die bed in d e first reactor at 130°C; while in the second reactor pure hydrogen chloride gas was flowing at 4.5 l/min and heated to keep d e bed temperamre at 240°C.
  • the dysprosium chloride thus produced had a total weight of 1987 g, a water content of less tiian 0.01 moles per mole formula unit ( ⁇ 0.067 w%) and was free from oxide impurities.

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

Abstract

Procédé de production d'halogénures métalliques des terres rares pratiquement pures et anhydres par déshydratation de leurs sels hydratés, ce procédé se caractérisant par l'amenée continue ou par lots des halogénures des terres rares hydratés dans un système de lit fluidisé comprenant un réacteur ou plusieurs réacteurs couplés en série; par l'introduction d'un agent déshydratant gazeux à une température élevée provoquant la déshydratation des halogénures des terres rares hydratés et par l'obtention d'halogénures des terres rares dont la teneur en eau maximale déterminée est exempte d'impuretés oxydées. Ce procédé peut également consister en une phase terminale reliée au système de lit fluidisé pour des teneurs en eau désirées inférieures à 0,05 moles d'eau par mole d'unité de la formule.
PCT/SE1996/001024 1995-08-17 1996-08-19 Procede de production de chlorures de terres rares anhydres Ceased WO1997007057A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU67606/96A AU6760696A (en) 1995-08-17 1996-08-19 Method for producing anhydrous rare earth chlorides

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9502865-0 1995-08-17
SE9502865A SE9502865D0 (sv) 1995-08-17 1995-08-17 Framställning av halider av sällsynta jordarter

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Publication Number Publication Date
WO1997007057A1 true WO1997007057A1 (fr) 1997-02-27

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PCT/SE1996/001024 Ceased WO1997007057A1 (fr) 1995-08-17 1996-08-19 Procede de production de chlorures de terres rares anhydres

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AU (1) AU6760696A (fr)
SE (1) SE9502865D0 (fr)
WO (1) WO1997007057A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008070887A3 (fr) * 2006-12-13 2008-07-31 Treibacher Ind Ag Procédé et appareil de production d'halogénures de terre rare anhydres cristallins
CN108298573A (zh) * 2018-04-13 2018-07-20 上海泰坦科技股份有限公司 一种无水氯化钇的制备方法
CN112607761A (zh) * 2020-12-28 2021-04-06 包头市明芯科技有限公司 一种高纯度无水氯化稀土的制备方法
WO2022012896A1 (fr) 2020-07-14 2022-01-20 Taniobis Gmbh Poudres d'alliage alsc à faible teneur en oxygène et leur procédé de production

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110540227A (zh) * 2018-10-29 2019-12-06 天津包钢稀土研究院有限责任公司 一种高品质无水稀土氯化物、溴化物的制备方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0395472A1 (fr) * 1989-04-28 1990-10-31 Rhone-Poulenc Chimie Halogénures de terres rares déshydratés et procédé de production de ceux-ci

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0395472A1 (fr) * 1989-04-28 1990-10-31 Rhone-Poulenc Chimie Halogénures de terres rares déshydratés et procédé de production de ceux-ci

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, Volume 78, No. 9, 5 March 1973, (Columbus, Ohio, USA), KOMISSAROVA, L.N. et al., "Chlorination of Oxides and Dehydration of Chloride Hydrates in a Vibration Fludized Bed", page 128, Abstract No. 45763c; & ISSLED. PROTSESSOV OBRAZOV. DISPERSN., 1971, 3, 266-272. *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008070887A3 (fr) * 2006-12-13 2008-07-31 Treibacher Ind Ag Procédé et appareil de production d'halogénures de terre rare anhydres cristallins
CN108298573A (zh) * 2018-04-13 2018-07-20 上海泰坦科技股份有限公司 一种无水氯化钇的制备方法
CN108298573B (zh) * 2018-04-13 2020-11-24 上海泰坦科技股份有限公司 一种无水氯化钇的制备方法
WO2022012896A1 (fr) 2020-07-14 2022-01-20 Taniobis Gmbh Poudres d'alliage alsc à faible teneur en oxygène et leur procédé de production
DE102020208782A1 (de) 2020-07-14 2022-01-20 Taniobis Gmbh Sauerstoffarme AlSc-Legierungspulver und Verfahren zu deren Herstellung
CN112607761A (zh) * 2020-12-28 2021-04-06 包头市明芯科技有限公司 一种高纯度无水氯化稀土的制备方法
CN112607761B (zh) * 2020-12-28 2022-04-08 包头市明芯科技有限公司 一种高纯度无水氯化稀土的制备方法

Also Published As

Publication number Publication date
AU6760696A (en) 1997-03-12
SE9502865D0 (sv) 1995-08-17

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