A kind of preparation method of high pure rare earth metals and device thereof
Technical field
The present invention relates to method and device thereof that a kind of metallothermy-vacuum distilling integrated process prepares high pure rare earth metals, belong to rare earth pyrometallurgical smelting field.
Background technology
Rare earth can't substituted excellent magnetic because of having, light, electrical property make it become the requisite basic materials of new and high technology functional materials such as magnetic, luminous and laser, storage hydrogen, superconduction; Be widely used in computingmachine, high density information storage, communication, conversion, high precision guiding, ray particle detection and high-tech areas such as record, information highway and national security strick precaution; Be widely used in VCM, motor, MRI and sound equipment etc. like magnetic king NdFeB permanent magnet; High specific energy Ni-MH battery material is widely used in communication and electromobile; The TbDyFe giant magnetostrictive material is widely used in zero-miss guidance and satnav, underwater communication, robot; Accurately control etc. of valve, K2LaI5 scintillation crystal can be applicable to nuclear medicine facility such as γ camera, positron emission tomography (PET) scanner.
Extensive development along with modern forward position art and fundamental research; To rare earth metal purity require increasingly high; Rare earth metal purity has played crucial effects in the new and high technology developing material, become one of key factor of influence and restriction material property.As adding the photoconductive fiber that high-purity rare-earth prepares, transfer rate is than the fast hundreds of times of silica fibre in the past; Oxygen level surpasses 1000 μ g/g in the TbDyFe giant magnetostrictive material, and its MS performance almost completely disappears, and therefore, requires O in feed metal terbium, the dysprosium<600 μ g/g, N<50 μ g/g, and C<70 μ g/g, non-rare earth metal is less than 100 μ g/g; When metal gadolinium absolute purity reached 4N, Gd5 (Si0.5Ge0.5) 4 magnetic cooling materials had huge magnetothermal effect, and when being lower than 3N, the huge magnetic entropy of its one-level becomes then completely dissolve; In field of light emitting materials; The used high pure metal terbium of high-power high light efficiency metal halid lamp, dysprosium, holmium, erbium, thulium, gadolinium, scandium etc., for obtaining high luminous efficiency, harsh unusually to the requirement of many transition metals; Because these impurity can form quenching centre; The quenching centre of trace just can make luminous efficiency sharply descend, and also can cause photochromicly departing from, light decay is unusual, the life-span reduces etc., requires non-rare earth metal impurity such as Fe, Si, Al, Ti, Cu, Mo equal size will be lower than 5ppm usually.
Chinese patent 91100877.2 has been reported a kind of working method of high-purity neodymium metal; This technology is done the de-carbon raw material with Neodymium trioxide, neodymium fluoride, quicklime; Neodymium metal to be clean is carried out the vacuum fusion de-carbon therewith under high temperature, vacuum condition, thereby obtain the neodymium metal of carbon content below 0.05%.The weak point of this technology is: 1) very little for the Impurity removal effect beyond the carbon, and also the removal effect of carbon impurity itself is also undesirable, and the purity of metal is not high; 2) owing in the vacuum fusion process, used Neodymium trioxide, neodymium fluoride, quicklime, therefore, unavoidably can introduce a large amount of oxygen, and, can cause to have being mingled with in a large number of Neodymium trioxide and quicklime in the neodymium metal because Neodymium trioxide and quicklime fusing point are higher.
Chinese patent CN87102206A has reported that a kind of metallothermy method of rare earth chloride prepares the method for rare earth metal, and its raw material is rare earth chloride or rare earth oxychloride, and reductive agent is basic metal or earth alkali metal, is mainly sodium, potassium.The technology that adopts is reduced to rare earth metal or rare earth alloy with reductive agent with rare earth chloride or oxychloride for being not less than in 70% the calcium chloride salt bath containing.The weak point of this technology is: 1) can not obtain very highly purified rare earth metal, especially gaseous impurities content is higher; 2) this process using calcium chloride as auxiliary salt bath, can cause to have a large amount of muriates in the metal.
Document (Lin Weiqing, Xiao Zugao. fused salt electrolysis process is produced the research [J] of high pure metal lanthanum. Jiangxi non-ferrous metal, 2003,17 (1): 32-34.) reported that a kind of fused salt electrolysis process produces the method for high pure metal lanthanum.It is raw materials used to be fluorescent lanthanum oxide, and ionogen is made up of same high-purity fluorescence level lanthanum fluoride and lithium fluoride, and graphite material is treated high purity graphite material.With the lanthanoid metal that this technology electrolysis obtains, its total amount of rare earth purity can reach 99.89%.The weak point of this technology is: 1) the metal gas impurity that obtains of this technology and non-rare earth metal foreign matter content are high; 2) this technology is high for the purity requirement of raw material and relevant auxiliary material, even has reached the fluorescence level.
Document (Yang Qingshan, Liu Shuping, Ou Yangyuping, Liu Shizhong, Su Zhengfu. high pure metal terbium Study on Preparation [J]. Jiangxi non-ferrous metal, 2005,19 (1): 31-32.) reported a kind of preparation method of high pure metal terbium.It adopts the method for high-temperature vacuum distillation that metal is distilled purification, become the high pure metal terbium to the distillation of crude metal terbium, and low-vapor pressure, insoluble metal impurity and most of gaseous impurities remains in the crucible.The weak point of this technology is: 1) the metal gas impurity that obtains of this technology and non-rare earth metal foreign matter content are high, and bad to vapour pressures such as Fe, Ni, the Cu impurity element removal effect close with the terbium metal vapour pressure; 2) to obtain the terbium metal absolute purity not high for this technology, mainly is the crude metal terbium preparation technology long flow path because of being used to purify, cause the crude metal terbium seriously polluted due to.
Document ([1] Zhang Changxin; Open newly organized. rare earth metallurgy principle and technology [M]. Beijing: metallurgical industry press; 1997:230-231. [2] Xu Guangxian chief editor. rare earth (middle volume). Beijing: metallurgical industry press, 1995:38-39.) introduced the method that a kind of lithium thermal reduction rare earth chloride prepares the high pure metal yttrium.The characteristics of this method are at first under low vacuum state; At 800~1100 ℃; The lithium and the rare earth chloride that are positioned over different positions be with the concurrent former reaction of surviving of gaseous form evaporation, adopts residual lithium chloride and metallic lithium removal in the metal that vacuum distillation method obtains reduction afterwards again.The weak point of this technology is that reduction process is vapour phase reduction reaction, unavoidably have some muriate on the one hand and taken out to run with lithium and take away, or volatilization cools off and can not react to each other at cold zone, causes significant loss; Its two under this temperature the rare earth chloride vaporator rate lower, can't muriate be flashed to gaseous state fully in the short period of time, and the vapour phase reduction long reaction time, make that this kind method consumed time is long, energy consumption is high, production efficiency is very low.
Summary of the invention
The invention provides a kind of method and device of producing high pure rare earth metals, this method is simple to operate, and energy consumption is low, and equipment requirements is low, and technical process is brief, and production process is polluted little, and product purity is high, is a kind of practicable high pure rare earth metals working method.
Adopt following technical scheme for reaching the present invention of foregoing invention purpose:
The present invention adopts lithium thermal reduction-vacuum distilling process integration to prepare high pure rare earth metals, that is:
(1) be raw material with the rare earth chloride, metallic lithium is a reductive agent, is placed in the reaction vessel;
(2) in reactive system, at first in protection of inert gas, be under 0.1~0.5Mpa and 850~1100 ℃ of temperature at pressure, metallic lithium and rare earth chloride generation liquid-liquid replacement(metathesis)reaction;
(3) then reactive system is evacuated to 10
-1~10
-3Pa (absolute pressure?), controlled temperature is at 900~1200 ℃, and metallic lithium and lithium chloride evaporation realize separating between slag and the metal, obtain high pure rare earth metals.
Be applicable to the device of above-mentioned preparation high pure rare earth metals method; See accompanying drawing 1; This device is made up of bell (1), pipe (2), scoop (3), body of heater (4), thermal baffle (5), reactor drum (6), heating unit (7), inflation system (8) and evacuation system (9); Reactor drum (6) top is placed thermal baffle (5) and scoop (3) successively and is placed in the body of heater (4); Bell (1) places on the body of heater (4) and closely and connects, and body of heater (4) is through pipe (2) and inflation system (8) and evacuation system (9), and heating unit (7) is positioned at body of heater (4) periphery.
In use, at first, place thermal baffle (5) and scoop (3) successively on reactor drum (6) top then with pack into reactor drum (6) and placing in the body of heater (4) of reactant; Again bell (1) is connected closely with body of heater (4), opens then after evacuation system (9) is evacuated to predetermined pressure to whole system, close evacuation system (9); Open inflation system (8), through pipe (2) filling with inert gas in body of heater (4) to predetermined pressure, close inflation system (8); Open heating unit (7) again, be heated to the preset temperature insulation, after insulation finishes; Opening vacuum system (9) found time to body of heater (4) through pipe (2); After distillation finishes, close evacuation system (9), open inflation system (8) through pipe (2) in body of heater (4) filling with inert gas to predetermined pressure; Treat that the entire reaction device is cooled to room temperature and comes out of the stove, promptly obtain high pure rare earth metals.
Rare earth in the rare earth chloride is meant a kind of in lanthanum, cerium, praseodymium, neodymium, gadolinium, terbium, dysprosium, holmium, erbium, lutetium, scandium, the yttrium, and its absolute purity is greater than 99.9wt.%;
Metallic lithium purity is greater than 99.9wt.%, its proportioning amount ratio theoretical amount excessive 0~15%;
Reaction vessel is metal titanium or tantalum system crucible, and the purity of crucible material is greater than 99wt.%;
Rare gas element is meant argon gas, and purity is greater than 99.999%
The prepared high pure rare earth metals that obtains is meant a kind of in lanthanum, cerium, praseodymium, neodymium, gadolinium, terbium, dysprosium, holmium, erbium, lutetium, scandium, the yttrium, and its absolute purity is greater than 99.9wt.%, and surplus is the impurity that total amount is no more than 0.1wt.%; Wherein rare earth metal impurity is less than 0.02wt.%; Non-rare earth metal impurity is less than 0.035wt.%, and C is less than 0.01wt.%, and O is less than 0.02wt.%; N is less than 0.01wt.%, and S is less than 0.005wt.%.
High pure rare earth metals preparation technology who adopts of the present invention and device have following several respects advantage:
1, reduction and distillation temperature that the present invention adopted are lower; Because titanium or the solubleness of tantalum in rare earth metal are very low at low temperatures, and as far as refractory metals such as heavy rare earth metal such as terbium, dysprosium, holmium, yttriums, reduction and distillation temperature are lower than its fusing point; Metal exists with solid phase form; Therefore, can greatly avoid other contaminating impurities of existence in crucible impurity or the crucible material, improve the purity of rare earth metal greatly.
2, reduction process reacting system pressure of the present invention is different from document ([1] Zhang Changxin; Open newly organized. rare earth metallurgy principle and technology [M]. Beijing: metallurgical industry press; 1997:230-231. [2] Xu Guangxian chief editor. rare earth (middle volume). Beijing: metallurgical industry press, 1995:38-39.) report.Its reactive system of the method for bibliographical information is to be in negative pressure state, and its reaction system of reduction process of the present invention is to be in barotropic state, on the one hand; As everyone knows, rare earth metal is active unusually, very easily with C, S, O, the effect of H gas; Reduction process of the present invention is carried out under the positive-pressure closing argon shield; Therefore, can effectively avoid the outer air admission reactive system of reactive system, thereby greatly reduce the content of gaseous impurities in the metal; On the other hand; Because reaction system is under the barotropic state, when liquid metal lithium or calcium reached equilibrium state with rare earth chloride and gas phase, metallic lithium or calcium and rare earth chloride just no longer volatilized; Therefore; Help improving utilization ratio of raw materials, improve the rare earth metal yield, middle-weight rare earths metal yield of the present invention can reach more than 92%.
3, reduction process of the present invention is a liquid phase reaction, and promptly liquid metal lithium or calcium and liquid rare earth chloride react, and reaction efficiency just is greatly enhanced like this, and the reduction reaction process just can be accomplished within 1~2 hour usually; And document ([1] Zhang Changxin; Open newly organized. rare earth metallurgy principle and technology [M]. Beijing: metallurgical industry press, 1997:230-231. [2] Xu Guangxian chief editor. rare earth (middle volume). Beijing: metallurgical industry press, 1995:38-39.) middle its reduction reaction of reported method is the vapour phase reduction process; Lithium and the rare earth chloride that promptly is positioned over different positions at first is evaporated near the reactor drum with gaseous form; Gaseous state lithium and gaseous state rare earth chloride generation reduction reaction because the space of reactive system is certain, need control liquid metal lithium and rare earth chloride slowly to evaporate; Therefore its reduction process is longer, generally needs 10 hours.Therefore, preparation efficiency of the present invention is higher, and energy consumption is low, and the processing and manufacturing cost is low.
4, device construction that the present invention adopts is simple, is easy to enlarge, and is applicable to production in enormous quantities.
In sum, technical process of the present invention is brief, and the rare earth metal yield is high, and production cost is low, and the prepared rare earth metal purity that obtains is high; The equipment that is adopted is simple, is easy to enlarge, and is applicable to industrial production in enormous quantities.
Description of drawings
Fig. 1: the synoptic diagram of apparatus of the present invention
Among Fig. 1, (1) bell, (2) pipe, (3) scoop, (4) body of heater, (5) thermal baffle, (6) reactor drum, (7) heating unit, (8) inflation system, (9) evacuation system.
Embodiment
Embodiment one
Adopt equipment and the device shown in the accompanying drawing one; In the titanium crucible that 99.5wt.% purity titanium material is processed, adding purity is the anhydrous lanthanum chloride 500g of 99.9wt.%, 99.9wt.% metallic lithium 45g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 950 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1100 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains lanthanoid metal 263.4g, yield 93%, and the lanthanum absolute purity is 99.957%, analytical results is following:
Table 1 lanthanoid metal composition analysis unit: ppm (wt.)
Embodiment two
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous lanthanum chloride 500g of 99.9wt.%, 99.9wt.% metallic lithium 48g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 950 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1100 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains lanthanoid metal 265.1g, yield 93.6%, and the lanthanum absolute purity is 99.964%, analytical results is following:
Table 2 lanthanoid metal composition analysis unit: ppm (wt.)
Embodiment three
Adopt equipment and the device shown in the accompanying drawing one; In the titanium crucible that 99.5wt.% purity titanium material is processed, adding purity is the anhydrous chlorides of rase neodymium 500g of 99.9wt.%, 99.9wt.% metallic lithium 45g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 1050 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1100 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains neodymium metal 264.4g, yield 92%, and the neodymium absolute purity is 99.952%, analytical results is following:
Table 3 neodymium metal composition analysis unit: ppm (wt.)
Embodiment four
Adopt equipment and the device shown in the accompanying drawing one; In the titanium crucible that 99.5wt.% purity titanium material is processed, adding purity is the anhydrous chlorides of rase praseodymium 500g of 99.9wt.%, 99.9wt.% metallic lithium 46g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 950 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1100 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metal praseodymium 271.2g, yield 95.2%, and the praseodymium absolute purity is 99.958%, analytical results is following:
Table 4 metal praseodymium composition analysis unit: ppm (wt.)
Embodiment five
Adopt equipment and the device shown in the accompanying drawing one; In the titanium crucible that 99.5wt.% purity titanium material is processed, adding purity is the anhydrous cerium chloride 500g of 99.9wt.%, 99.9wt.% metallic lithium 48g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 850 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 950 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metallic cerium 268.0g, yield 95%, and the cerium absolute purity is 99.954%, analytical results is following:
Table 5 metallic cerium composition analysis unit: ppm (wt.)
Embodiment six
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous chlorides of rase terbium 500g of 99.9wt.%, 99.9wt.% metallic lithium 44g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 980 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1200 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains terbium metal 277g, yield 92.5%, and the terbium absolute purity is 99.947%, analytical results is following:
Table 6 terbium metal composition analysis unit: ppm (wt.)
Embodiment seven
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous chlorides of rase dysprosium 500g of 99.9wt.%, 99.9wt.% metallic lithium 44g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 980 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1200 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metal dysprosium 279.8g, yield 92.6%, and the dysprosium absolute purity is 99.947%, analytical results is following:
Table 7 metal dysprosium composition analysis unit: ppm (wt.)
Embodiment eight
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous chlorides of rase yttrium 500g of 99.9wt.%, 99.9wt.% metallic lithium 60g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 1000 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1200 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metallic yttrium 211.5g, yield 93%, and the yttrium absolute purity is 99.969%, analytical results is following:
Table 8 metallic yttrium composition analysis unit: ppm (wt.)
Embodiment nine
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous chlorides of rase gadolinium 500g of 99.9wt.%, 99.9wt.% metallic lithium 45g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 980 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1200 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metal gadolinium 277g, yield 93%, and the gadolinium absolute purity is 99.952%, analytical results is following:
Table 9 metal gadolinium composition analysis unit: ppm (wt.)
Embodiment ten
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous chlorides of rase lutetium 500g of 99.9wt.%, 99.9wt.% metallic lithium 45g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 980 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1200 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metal lutetium 277g, yield 93%, and the gadolinium absolute purity is 99.948%, analytical results is following:
Table 10 metal lutetium composition analysis unit: ppm (wt.)
Embodiment 11
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous chlorides of rase holmium 500g of 99.9wt.%, 99.9wt.% metallic lithium 44g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 980 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1200 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metal holmium 283g, yield 93.2%, and the holmium absolute purity is 99.950%, analytical results is following:
Table 11 metal holmium composition analysis unit: ppm (wt.)
Embodiment 12
Adopt equipment and the device shown in the accompanying drawing one; In the tantalum crucible that 99.9wt.% purity tantalum material is processed, adding purity is the anhydrous chlorides of rase scandium 500g of 99.9wt.%, 99.9wt.% metallic lithium 43g, under 99.999% argon gas atmosphere (>0.1MPa); Be warming up to 980 ℃ (reacting system pressure remains on below the 0.5MPa in the temperature-rise period); And be incubated 1 hour, system is evacuated to distills removal of impurities below the 0.1Pa then, at 1200 ℃; Be incubated after 3 hours and finish distillation, re-fill argon gas and be cooled to room temperature and come out of the stove.Reduction obtains metal scandium 305.6g, yield 92.6%, and the scandium absolute purity is 99.952%, analytical results is following:
Table 12 metal scandium composition analysis unit: ppm (wt.)