CN1159101C - Process for preparing super-stable Y zeolite containing rare-earth elements - Google Patents

Abstract

The present invention relates to a preparation method of overstable Y zeolite containing rare earth, which comprises: overstable Y zeolite having a sodium oxide content of 3 to 5 wt% is mixed with a solution of a rare earth compound to obtain slurry; the obtained slurry is ground for at least one minute under the condition that the shearing stress is at least 10 kg/cm<2>; in the slurry, the weight ratio of the overstable Y zeolite to the rare earth compound to water is 1: (0.001 to 0.5): (1 to 10). The method has the advantages of quickness, simplicity and directness. Furthermore, the zeolite prepared with the method has the advantages of high water thermal stability, high activity stability, high sodium resisting capability and high heavy metal pollution resisting capability.

Description

A kind of preparation method of super-stable Y zeolite containing rare-earth elements

Technical field

The invention relates to the preparation method of y-type zeolite, more particularly, is the preparation method about a kind of super-stable Y zeolite containing rare-earth elements.

Background technology

For activity and the structural stability that improves overstable gamma zeolite, usually in overstable gamma zeolite, introduce the rare earth component, one of common method of introducing the rare earth component is the rare earth ion in the solution to be deposited on the catalyst of y-type zeolite with alkaline solution, and two of common method is methods of ion-exchange.

CN1034680A discloses a kind of rich silicon molecular sieve by crystal Cracking catalyst that contains rare earth, and this catalyst is an active component with the Silicon-rich HY zeolite that contains rare earth of the heavy % of 5-40, is aided with the Al that comprises of the heavy % of 95-60 ₂O ₃, SiO ₂, SiO ₂-Al ₂O ₃At interior full synthesis carrier, or contain the semi-synthetic carrier of the silica gel of the heavy % of 15-30 or aluminium glue stick and constitute, contain in the Silicon-rich HY zeolite of rare earth, rare earth is all with RE ₂O ₃State exist, the exchangeable cations position is by H ⁺Or Na ⁺Occupy, the similar conventional ultrastable of the X light powder diffraction spectrogram of this zeolite, but be the RE that a disperse is arranged on the 27-29 ° of position at 2 θ angles ₂O ₃Characteristic peak.This rich silicon molecular sieve by crystal that contains rare earth can be by two kinds of method preparations, and first method comprises with NaOH or NH ₄OH precipitates RECl ₃Mixed solution obtains gluey rare-earth hydroxide, and what obtain during with hydrochloric acid or sulfuric acid precipitation waterglass or Ludox or synthetic A, X, Y molecular sieve contains SiO ₂Mother liquor obtains amorphous gluey SiO ₂, then, with gluey rare-earth hydroxide, amorphous gluey SiO ₂Press RE with the NaY molecular sieve ₂O ₃: SiO ₂: the NaY weight ratio is 0.05-0.5: 0.02-0.3: 1 ratio mixes, and the pH to 10-13 with NaOH solution adjusting slurries filters, and is (the NH of the heavy % of 1-30 again with concentration ₄) ₂SO ₄Solution is by (NH ₄) ₂SO ₄: NaY is the weight ratio of 0.5-2.0, carries out ion-exchange 1-3 time 35 to the temperature of boiling, each 5-60 minute, and filtration, at 450-650 ℃, in the 20-100% water vapour atmosphere roasting 0.5-4 hour.Second method comprises RECl ₃Solution and 20-80 ℃ the NaY zeolite slurry that contains mother liquor is by RE ₂O ₃: SiO ₂: NaY is 0.05-0.5: 0.02-0.3: 1 weight ratio mixes, with NaOH solution the pH value of mixed serum is transferred to 10-13, filter, with concentration is that the ammonium sulfate of the heavy % of 1-30 is that the weight ratio of 0.5-2.0 is 35 ℃ of exchanges 1-3 time to the boiling temperature by ammonium sulfate: NaY, each 5-60 minute, filter cake after the ammonium exchange is at 450-650 ℃, and 20-100% steam burnt 0.5-4 hour down.

CN1127161A discloses a kind of preparation method of rare earth-containing rich silicon ultra stabilization Y molecular sieve, this method comprise (1) with silica alumina ratio greater than 3.5 the NaY molecular sieve and the solid RECl of porphyrize ₃Make its water content be lower than 10 heavy %, NaY molecular sieve and RECl after (2) will handle through hydrothermal treatment consists respectively ₃Press RECl ₃: NaY=0.02-0.60: 1 weight ratio mixes while hot or mixes under dry atmosphere, and (3) feed the SiCl that dry atmosphere is carried in said mixture ₄Gas, in 150-550 ℃ of reaction 10 minutes to 5 hours, wherein, the water content of dry air was lower than 900ppm, SiCl in reactor ₄Consumption press SiCl ₄: NaY=0.10-0.80: 1 weight ratio is calculated, and the reaction back purged in reactor 10 minutes to 2 hours with this dry air, and the Na in the molecular sieve is removed in (4) washing ⁺, Cl ^-, Al ³⁺Etc. the solubility accessory substance.

In general, ion-exchange comprises mixes y-type zeolite with a kind of solution that contains rare earth ion, at liquid-solid ratio 5-20, carry out ion-exchange at least 30 minutes under temperature 60-100 ℃ the condition.

As everyone knows, some overstable gamma zeolite contains the sodium oxide molybdena about 4 heavy %, and the sodium ion in the contained sodium oxide molybdena occupies the exchangeable cations position in the overstable gamma zeolite, and, basically in the supercage of zeolite.If replace these sodium ions with rare earth ion, undoubtedly, can improve the acidity of overstable gamma zeolite, can play again and stablize zeolite structured effect.Yet, adopt with rare-earth precipitation on zeolite method and with the RECl of drying ₃Mix with overstable gamma zeolite and to use SiCl again ₄The method of handling all can not reach the purpose of replacing these sodium ions with rare earth ion.And the method for employing ion-exchange, though but generating unit is divided displacement,, the time of first ion-exchange is longer, and temperature is also higher, and second, even under higher temperature and longer swap time such condition, the content of sodium oxide molybdena also is difficult to be reduced to the satisfied degree of other people.Just because of this, adopted prior art, when preparing the hyperastable Y-type RE zeolite with the overstable gamma zeolite that contains 4 heavy % left and right sides sodium oxide molybdenas, the sodium content of the hyperastable Y-type RE zeolite that obtains is higher, and the ability of hydrothermal stability, activity stability, anti-sodium and preventing from heavy metal pollution is also relatively poor.

Summary of the invention

The purpose of this invention is to provide a kind of new preparing and have higher hydrothermal stability, activity stability, the preparation method of the super-stable Y zeolite containing rare-earth elements of better anti-sodium and heavy metal pollution ability.

The preparation method of super-stable Y zeolite containing rare-earth elements provided by the invention utilizes the principle of friction chemistry, and the slurries that will contain overstable gamma zeolite and rare earth ion grind, to reach the purpose of ion-exchange.In process of lapping, bring in constant renewal in owing to participate in the friction surface of reaction, again because friction can produce local upper state, thereby, little more a lot of than the required activation energy of heat chemistry, in heat chemistry, be difficult in friction, also being activated by the sodium ion under the rare earth ion exchanged, replaced by rare earth ion.

It is that the overstable gamma zeolite of the heavy % of 3-5 mixes with a kind of rare earth compound solution that the preparation method of super-stable Y zeolite containing rare-earth elements provided by the invention comprises sodium oxide content, make a kind of slurries, the slurries that obtain are ground, wherein, in the described slurries, the weight ratio of overstable gamma zeolite, rare earth compound and water is 1: 0.001-0.5: 1-10, the shear stress of grinding is at least 10 kilograms per centimeter ², milling time is no less than 1 minute.

The super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention has following advantage:

1. the speed of method ion-exchange provided by the invention is faster, for example, adopts method provided by the invention, with overstable gamma zeolite and the RECl of sodium oxide content 4.3 heavy % ₃Solution mixes, slurries mesolite: RECl ₃: H ₂The weight ratio of O is 1: 0.135: 1.5, grinds after 5 minutes, and sodium oxide content is reduced to 0.8 heavy %, and adopt existing ion-exchange, be to carry out ion-exchange after 1 hour under 10,90 ℃ the high temperature in liquid-solid ratio, sodium oxide content is also up to 1.4 heavy % in the zeolite.

2. adopt the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention to have higher hydrothermal stability.For example, as Figure 1-3, compare with the overstable gamma zeolite that contains rare earth for preparing with ion-exchange, handle through 800%100 steam agings, the crystallization reservation degree of the super-stable Y zeolite containing rare-earth elements for preparing with method provided by the invention, specific surface reservation degree, pore volume reservation degree with the decrease speed of ageing time will be slowly many.

3. adopt the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention to have higher activity stability.As shown in Figure 4, the super-stable Y zeolite containing rare-earth elements of method provided by the invention preparation combine with matrix such as boehmite, kaolin make the catalytic cracking catalyst that contains zeolite 25 weight %, and catalyst is carried out burin-in process down with 100% water vapour at 800 ℃.Compare with the reference catalyst of the super-stable Y zeolite containing rare-earth elements of ion-exchange preparation with containing same amount, the light oil microactivity of catalyst that contains the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention is considerably slower than reference catalyst with underspeeding of ageing time.

4. adopt the super-stable Y zeolite containing rare-earth elements of method provided by the invention preparation to have excellent catalytic performance more, show that this zeolite has higher cracking activity, lower coke selectivity and the gasoline selective of Geng Gao, as shown in table 5.

5. adopt the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention to have than live with the stronger anti-sodium of the zeolite process of art methods preparation pollution capacity and preventing from heavy metal pollution ability.

For example, identical at other constituent content, difference only is that the super-stable Y zeolite containing rare-earth elements that is contained is different, contain with the catalyst of the super-stable Y zeolite containing rare-earth elements of method provided by the invention preparation and contain with in the reference catalyst of the super-stable Y zeolite containing rare-earth elements of ion-exchange preparation respectively dipping last 0.5 weigh %, 1.0 the sodium of heavy % and 1.5 heavy %, and 800 ℃ with 100% steam treatment 4 hours the catalyst of sodium after polluting, content with dirty sodium in the catalyst increases, the speed that contains the catalyst light oil microactivity reservation degree decline of the super-stable Y zeolite containing rare-earth elements for preparing with method provided by the invention is much more slowly than reference catalyst, as shown in Figure 5.

Again for example, identical at other constituent content, difference only is that the super-stable Y zeolite containing rare-earth elements that is contained is different, contains with the catalyst of the super-stable Y zeolite containing rare-earth elements of method provided by the invention preparation and contain to sneak into 5000 and 10000ppmV in the reference catalyst of the super-stable Y zeolite containing rare-earth elements for preparing with ion-exchange respectively ₂O ₅, and 800 ℃ with 100% steam treatment 4 hours, after pollution of vanadium, contain light oil microactivity reservation degree with the super-stable Y zeolite containing rare-earth elements catalyst of method preparation provided by the invention, catalyst mesolite crystallization reservation degree all is much higher than reference catalyst.

Description of drawings

Fig. 1 is when carrying out hydrothermal treatment consists for 800 ℃, and the crystallization reservation degree of different super-stable Y zeolite containing rare-earth elements is with the variation diagram of the time of processing;

Fig. 2 is when carrying out hydrothermal treatment consists for 800 ℃, and the specific surface reservation degree of different super-stable Y zeolite containing rare-earth elements is with the variation diagram of the time of processing;

Fig. 3 is when carrying out hydrothermal treatment consists for 800 ℃, and the pore volume reservation degree of different super-stable Y zeolite containing rare-earth elements is with the variation diagram of the time of processing;

Fig. 4 is when carrying out hydrothermal aging for 800 ℃, and the light oil microactivity of catalyst that contains different super-stable Y zeolite containing rare-earth elements is with the variation diagram of ageing time;

Fig. 5 is the variation diagram of different catalysts light oil microactivity reservation degree with the sodium content on polluting;

The specific embodiment

According to method provided by the invention, the overstable gamma zeolite that described sodium oxide content 3-5 is heavy can be purchased and get, and also can prepare with the following method: sodium oxide content 13-14 is weighed the NaY zeolite of % and contains NH ₄ ⁺Aqueous solution, under 60-100 ℃ temperature, carry out ion-exchange at least 30 minutes, NH ₄ ⁺The aqueous solution in NH ₄ ⁺Concentration be the 0.1-2 mol, when carrying out ion-exchange, liquid-solid ratio is 5-20.Zeolite after the ion-exchange is spent deionised water to there not being acid ion, under 650 ℃ of 100% water vapour atmosphere, carried out hydrothermal treatment consists 1-3 hour, get the overstable gamma zeolite of the heavy % of sodium oxide content 3-5.Wherein, the described NH that contains ₄ ⁺The aqueous solution in, NH ₄ ⁺By water soluble salt of ammonia, provide as ammonium chloride, ammonium sulfate, ammonium nitrate etc.

Described rare earth compound is selected from one or more in the water-soluble rare earth compound of energy, is preferably the chloride and/or the nitrate of rare earth, the chloride of preferred especially rare earth.Described rare earth is selected from one or more in lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, the lutetium, be preferably in lanthanum, cerium, lanthanum rich mischmetal and the cerium-rich mischmetal one or more, because lanthanum rich mischmetal and cerium-rich mischmetal are easy to obtain more, therefore more preferably lanthanum rich mischmetal or cerium-rich mischmetal.

According to method provided by the invention, described grinding can be adopted various abrasive method, as the method for underhand polish, mechanical lapping.The preferred method that adopts mechanical lapping is as carrying out abrasive method in colloid mill.During grinding, shear stress is at least 10 kilograms per centimeter ², be preferably the 10-100 kilograms per centimeter ², 10-50 kilograms per centimeter more preferably ²

The longer ion-exchange effect of milling time can be better, and still, in general milling time just can reach purpose of the present invention at 15 minutes with interior, so the preferred 1-15 of milling time minute, more preferably 2-10 minute.

According to method provided by the invention, the raising of grinding temperature helps the carrying out of ion-exchange, but difference and not obvious, and grinding temperature can be 5-100 ℃, for reducing energy consumption, carries out under 10-50 ℃ usually, more preferably carries out under 10-40 ℃ temperature.

The weight ratio of overstable gamma zeolite, rare earth compound and water is very important in the slurries in method provided by the invention, the too rare grinding effect of slurries is bad, too dense being difficult to again operates, and do not reach the purpose of fully carrying out ion-exchange, in general, the weight ratio of overstable gamma zeolite, rare earth compound and water is 1 in the slurries: 0.001-0.5: 1-10 is preferably 1: 0.05-0.3: 1-4.5.

According to method provided by the invention, if wish in zeolite, to introduce more rare earth component, perhaps wish in zeolite, to introduce the rare earth component of deposition form, can after grinding, add a kind of alkaline solution, make the pH value of slurries rise to 5-10, be preferably 6-8, rare earth ion in the solution is deposited on the zeolite with the form of rare-earth hydroxide, and continue to grind at least 1 minute, preferred 1-15 minute, more preferably 2-10 minute.Wherein said aqueous slkali can be selected from one or more in the various inorganic and organic base solution, and as in alkali-metal hydroxide solution, ammonia spirit, the organic amine solution one or more, more excellent is ammonia spirit.

According to Preparation of catalysts method provided by the invention, the slurries that obtain after the grinding spend deionised water after filtration to there not being acid ion, and drying obtains super-stable Y zeolite containing rare-earth elements.The slurries that obtain can directly use grinding when the preparation catalyst after also can use the super-stable Y zeolite containing rare-earth elements that obtains after filtration, washing, the drying.For example, when preparation catalytic cracking Cracking catalyst, the super-stable Y zeolite containing rare-earth elements that the slurries that obtain after grinding or filtration, washing, drying can be obtained is with material or their precursor of forming the catalytic cracking catalyst carrier and water is pulled an oar, dry, washing and obtain catalytic cracking catalyst after the drying once more.

The super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention can be used as various catalyst, as the active component of catalytic cracking catalyst, hydrocracking catalyst, hydrotreating catalyst, is especially suitable for use as the active component of catalytic cracking catalyst.

Super-stable Y zeolite containing rare-earth elements provided by the invention is combined with catalytic cracking catalyst carrier or matrix, can obtain a kind of catalytic cracking catalyst.

In general, in described catalytic cracking catalyst, be benchmark with the catalyst total amount, the content of described super-stable Y zeolite containing rare-earth elements is the heavy % of 5-60, is preferably the heavy % of 5-35, the content of catalyst carrier is the heavy % of 40-95, is preferably the heavy % of 65-95.

The preparation method of described catalytic cracking catalyst comprises and will form the material of catalyst carrier or their precursor, the super-stable Y zeolite containing rare-earth elements of method provided by the invention preparation or the slurries and the water that contain this overstable gamma zeolite are pulled an oar together, drying, washing, dry once more.

According to catalyst provided by the invention, described catalyst carrier or matrix are carrier or the matrix that is commonly used for catalytic cracking catalyst.As being amorphous aluminum silicate, also can be the mixture of al binder and clay.

When described catalyst carrier is amorphous aluminum silicate, be benchmark with the total catalyst weight, the content of super-stable Y zeolite containing rare-earth elements is the heavy % of 5-60, be preferably the heavy % of 5-35, the heavy % of silica content 30-70 is preferably the heavy % of 40-60, alumina content is the heavy % of 10-50, is preferably the heavy % of 20-40.

When described catalyst carrier is the mixture of al binder and clay, be benchmark with the total catalyst weight, the content of super-stable Y zeolite containing rare-earth elements is the heavy % of 5-60, the heavy % of preferred 5-35, al binder is (with Al ₂O ₃Meter) content is the heavy % of 10-45, is preferably the heavy % of 20-40, and the content of clay is the heavy % of 30-60, is preferably the heavy % of 40-60.

Silicon in the described amorphous aluminum silicate is provided by Ludox and/or waterglass, and the aluminium in the described amorphous aluminum silicate is provided by aluminium colloidal sol and/or boehmite.

Described al binder is selected from aluminium colloidal sol and/or boehmite.Described clay is selected from one or more in the various clays that are commonly used for the catalytic cracking catalyst component.As in kaolin, halloysite, imvite, the diatomite etc. one or more, be preferably kaolin.

In order to improve catalyst strength and improve quality of gasoline in the catalytic cracking reaction product, contain in the catalytic cracking catalyst of super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention and can also contain phosphorus, with P ₂O ₅Meter, phosphorus content are the heavy % of 0.4-8, are preferably the heavy % of 0.5-5.

In described catalytic cracking catalyst, can partly replace the overstable gamma zeolite that contains rare earth of method provided by the invention preparation with other zeolite, described other zeolite is selected from one or more in the hydrogen Y zeolite (HY) that is commonly used for the catalytic cracking catalyst active component, rare earth exchanged Y zeolite (REY), rare earth hydrogen Y zeolite (REHY), overstable gamma zeolite (USY), phosphorous y-type zeolite, ZSM-5 zeolite, Beta zeolite, the modenite.If contain other zeolite, the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention and the weight ratio of other zeolite are 1: 0.1-10 is preferably 1: 0.2-5.

The preferred a kind of aging boehmite slurries of described boehmite, the preparation method of these slurries comprises boehmite and deionized water by 1: 1-10, be preferably 1: the weight ratio of 1-5 is mixed making beating, adding HCl and boehmite weight ratio is 1: 0.01-0.4, be preferably 1: the hydrochloric acid of 0.1-0.3, be warming up to 40-80 ℃, preferred 50-60 ℃ aging 10-60 minute, preferred 20-30 minute, promptly get described aging boehmite slurries.

In the preparation method of described catalytic cracking catalyst, in pulping process, conventional amount used when the consumption of each material is the preparation catalytic cracking catalyst, as when adopting amorphous aluminum silicate as catalyst carrier or matrix, the consumption of super-stable Y zeolite containing rare-earth elements should make and contain the heavy % of 5-60 in the final catalyst, be preferably the super-stable Y zeolite containing rare-earth elements of the heavy % of 5-35, the consumption of Ludox or waterglass should make and contain the heavy % of 30-70 in the final catalyst, be preferably the silica of the heavy % of 40-60, the consumption of aluminium colloidal sol or boehmite should make and contain the heavy % of 10-50 in the final catalyst, is preferably the aluminium oxide of the heavy % of 20-40.As to adopt al binder and clay be catalyst carrier or matrix, and the consumption of aluminium colloidal sol and/or boehmite should make and contain the heavy % of 10-45 in the final catalyst; Be preferably the aluminium oxide of 20-40, the consumption of clay should make and contain the heavy % of 30-60 in the final catalyst, is preferably the clay of the heavy % of 40-60.It is the heavy % of 20-40 that the consumption of deionized water should make the solid content of the slurries that obtain, and is preferably the heavy % of 25-35.

If partly replace the overstable gamma zeolite that contains rare earth of method provided by the invention preparation with aforesaid other zeolite, can described other zeolite and the super-stable Y zeolite containing rare-earth elements for preparing of method provided by the invention mix making beating with catalyst carrier or matrix or its precursor and deionization together.

When containing phosphorus in the described catalytic cracking catalyst, can in slurries, add a kind of phosphorus-containing compound at pulping process, described phosphorus-containing compound can be selected from one or more in phosphoric acid, phosphorous acid, ammonium phosphate, ammonium dihydrogen phosphate (ADP), the diammonium hydrogen phosphate.The consumption of described phosphorus-containing compound should make and contain the heavy % of 0.4-8 in the final catalyst, the P of the heavy % of preferred 0.5-5 ₂O ₅Also can in washing process as described below, introduce phosphorus.

Described dry drying means when using conventional preparation catalytic cracking catalyst, as can using airing, oven dry or spray-dired method, dry temperature can be preferably 120-650 ℃ from room temperature to 700 ℃.

The purpose of described washing is to remove the wherein Na of solubility ⁺, materials such as acid ion, the method for washing can adopt conventional washing methods, as with deionized water and the making beating of dried catalyst, filters then, or directly uses the deionized water rinsing catalyst.

By washing, can also in catalyst, introduce phosphorus, method is with containing P ₂O ₅0.1-10 heavy % is preferably the heavy % of 0.1-5, pH value be 2.5-10, be preferably 3.5-5.5 phosphorus-containing compound the solution washing catalyst at least once, in catalyst, introduce 0.4-8 and weigh %, be preferably 0.5-5 and weigh the phosphorus of % (with P ₂O ₅Meter), the 5-20 that described phosphorus-containing compound solution is catalyst weight when washing at every turn doubly is preferably 10-15 doubly.Described phosphorus-containing compound can be any one water-soluble phosphorus-containing compound, is preferably the ammonium salt of phosphoric acid.

The following examples will the present invention will be further described.

Example 1

Prepare super-stable Y zeolite containing rare-earth elements by method provided by the invention.

Take by weighing overstable gamma zeolite (lattice constant is 2.468 nanometers, and Qilu Petrochemical company Zhou village catalyst plant is produced) and the RECl of 500 gram sodium oxide contents, 4.3 heavy % ₃(produce in the chemical plant, packet header, wherein, in oxide, La ₂O ₃, CeO ₂With the weight ratio of other rare-earth oxides be 1: 2: 0.2.) the solution mixing, zeolite, RECl ₃With the weight ratio of water be 1: 0.135: 1.5.The slurries that obtain are placed JTM-50 vertical colloid mill (Xinguang Motive Power Machine Corp., Shenyang of Ministry of Astronautics Industry product), ground 5 minutes under 20 ℃ temperature, the shear stress of grinding is 20 kilograms per centimeter ²Filter, spend the deionised water solid product to there not being chlorion, 120 ℃ of oven dry obtain the super-stable Y zeolite containing rare-earth elements B that adopts method provided by the invention to prepare.Its chemical composition and physico-chemical property are listed in the table 1.

Wherein, Na ₂O content adopts aas determination, the content of rare earth oxide, silica, aluminium oxide adopts the x-ray fluorescence spectrometry method to measure, the avalanche temperature adopts Differential scanning calorimetry to measure on Du Pont's 2100 type differential thermal analyzers, crystallization reservation degree and lattice constant adopt X-ray diffraction method to measure, and pore volume, specific surface adopt nitrogen adsorption capacity method to measure.

Example 2

Prepare super-stable Y zeolite containing rare-earth elements by method provided by the invention.

Taking by weighing sodium oxide content is overstable gamma zeolite (with example 1) 500 gram and the RECl of 4.3 heavy % ₃(with example 1) solution mixes zeolite, RECl ₃With the weight ratio of water be 1: 0.2: 2.0.The slurries that obtain are placed JTM-50 vertical colloid mill (with example 1), ground 5 minutes under 12 ℃ of temperature, grinding shear stress is 40 kilograms.Add 1: 1 ammoniacal liquor, regulate the pH value to 6.0 of slurries, continue to grind 5 minutes, filter, spend the deionised water solid product to there not being chlorion, 120 ℃ of oven dry obtain the super-stable Y zeolite containing rare-earth elements C that adopts method provided by the invention to prepare.Its chemical composition and physico-chemical property are listed in the table 1.

Comparative Examples 1

Prepare super-stable Y zeolite containing rare-earth elements with ion-exchange.

Take by weighing described overstable gamma zeolite 500 grams that contain sodium oxide molybdena 4.3 heavy % of example 1, with 5000 ml concns be the RECl of 5 heavy % ₃(with example 1) solution mixes, and is warming up to 90 ℃, under agitation carries out ion-exchange 60 minutes, filters, and spends the deionised water solid product to there not being chlorion, and 120 ℃ of oven dry obtain reference super-stable Y zeolite containing rare-earth elements D.Its chemical composition and physico-chemical property are listed in the table 1.

Comparative Examples 2

Adopt the ion-exchange and the precipitation method to prepare the reference super-stable Y zeolite containing rare-earth elements.

Take by weighing described overstable gamma zeolite 500 grams that contain sodium oxide molybdena 4.3 heavy % of example 1, with 5000 ml concns be the RECl of 5 heavy % ₃(with example 1) solution mixes, be warming up to 90 ℃, under agitation carry out ion-exchange 60 minutes, be cooled to room temperature, add 1: 1 ammoniacal liquor, regulate the pH value to 6.0 of slurries, stirred 15 minutes, and filtered, spend the deionised water solid product to there not being chlorion, 120 ℃ of oven dry obtain reference super-stable Y zeolite containing rare-earth elements E.It is formed and physico-chemical property is listed in the table 1.

Table 1

The example deviation	The zeolite numbering	The chemical composition of zeolite, heavy %				The avalanche temperature, ℃	Crystallization reservation degree, %	Lattice constant, nanometer
									Na 2O	RE 2O 3	SiO 2	Al 2O 3
		1	B	0.8	5.8								74.5	18.9	1020	75	2.449
2	C					0.9	9.0	73.7	16.4	1015	76	2.449
		Comparative Examples 1	D	1.4	5.2								74.6	18.8	1009	75	2.450
Comparative Examples 2	E					1.3	8.5	73.5	16.7	1019	77	2.451

The result of table 1 shows, compare the method provided by the invention that adopts with Comparative Examples, though the reaction time is short, temperature is also low, but the sodium oxide content of the super-stable Y zeolite containing rare-earth elements that obtains but obviously reduces, and method provided by the invention is adopted in this explanation, have more rare earth ion to substitute the sodium ion on the cation position, ion-exchange effect is better.

Example 3-4

The hydrothermal stability of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention is adopted in following example explanation.

The super-stable Y zeolite containing rare-earth elements B and the C of example 1 and 2 preparations are handled with 100% water vapour at 800 ℃, crystallization reservation degree is over time successively shown among Fig. 11 and 2, successively shown among Fig. 25 and 6, pore volume reservation degree is successively shown among Fig. 39 and 10 over time for specific surface reservation degree.

Wherein, degree of crystallinity * 100% of the preceding zeolite of the degree of crystallinity/hydrothermal aging of zeolite behind crystallization reservation degree=hydrothermal aging; Specific surface * 100% of zeolite before the specific surface/hydrothermal aging of zeolite behind specific surface reservation degree=hydrothermal aging; Pore volume * 100% of zeolite before the pore volume/hydrothermal aging of zeolite behind pore volume reservation degree=hydrothermal aging.

Comparative Examples 3-4

The hydrothermal stability of following Comparative Examples explanation reference super-stable Y zeolite containing rare-earth elements.

Method by example 3 is carried out hydrothermal treatment consists to zeolite, different is with Comparative Examples 1 and the 2 reference zeolite D that prepare and E replacement B and C, crystallization reservation degree is over time successively shown among Fig. 13 and 4, successively shown among Fig. 27 and 8, pore volume reservation degree is successively shown among Fig. 3 11 and 12 over time for specific surface reservation degree.

The result of Fig. 1-3 shows that (1) and reference contain rare earth zeolite facies ratio, after hydrothermal treatment consists, adopt crystallization reservation degree, specific surface reservation degree and the pore volume reservation degree of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention all to be higher than the reference zeolite, (2) contain rare earth zeolite facies ratio with reference, with the prolongation of hydrothermal treatment consists time, adopt the decrease speed of crystallization reservation degree, specific surface reservation degree and pore volume reservation degree of super-stable Y zeolite containing rare-earth elements of method provided by the invention preparation slower.This explanation adopts the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention to have the hydrothermal stability higher than prior art.

Example 5-6

Following example goes on to say the hydrothermal stability with the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention.

(1) (solid content is 34.8 heavy % to take by weighing 24.4 gram (dry basis) boehmites, Shandong Aluminum Plant produces) and 70 gram deionized waters mixing making beating, adding 20 gram concentration again is the hydrochloric acid of 37 heavy %, stirs, be warming up to 70 ℃ and wore out the boehmite slurries that obtain wearing out 1.5 hours.

(2) super-stable Y zeolite containing rare-earth elements 32 with example 1 and 2 preparations restrains (dry basis), 50 gram (dry basis) kaolin (solid content 85 heavy %, Suzhou kaolin company produces) respectively the aging boehmite with the preparation of (1) method of employing mix, obtain a kind of slurries, the solid content of these slurries is 30 heavy %, with these slurries 110 ℃ of oven dry, with solid product of 10 times of deionized water washings, 110 ℃ of oven dry, the solid product that obtains is ground into 20-40 purpose particle, obtains containing the Cracking catalyst C of the super-stable Y zeolite containing rare-earth elements of useful method preparation provided by the invention ₁And C ₂Catalyst is formed and physico-chemical property is listed in the table 2.The catalyst composition is got by calculating.

(3) 800 ℃ with 100% water vapour to catalyst C ₁And C ₂Carrying out hydrothermal aging, is the catalyst C that raw material is estimated the processing of different hydrothermal aging time with straight distillation light diesel oil shown in the table 3 ₁And C ₂Light oil microactivity, be reflected in the small stationary bed bioreactor and carry out, reaction temperature is 460 ℃, weight (hourly) space velocity (WHSV) is 16 hours ^-1, agent weight of oil ratio is 3.2.Under the different ageing times, catalyst C ₁And C ₂Micro-activity shown among Fig. 4 13 and 14.Product adopts gas chromatographic analysis.

Wherein, light oil microactivity (MA) is calculated by following formula:

$\mathrm{MA}=100-\frac{W_1(100-\frac{A_1}{A_1+A_2}\&times;100)}{W}$

In the formula: W ₁It is heavy that-liquid is received oil, gram

The W-feed oil is heavy, gram

A ₁-gasoline fraction spectrogram area

A ₂-fraction of diesel oil spectrogram area

Comparative Examples 5-6

Following Comparative Examples goes on to say the hydrothermal stability that reference contains the rare earth zeolite.

(1) presses the boehmite that (1) preparation among the example 5-6 is worn out.

(2) (2) of pressing among the example 5-6 prepare catalyst, and different reference zeolite D that just use Comparative Examples 1 and 2 preparations respectively and E replacement obtain reference catalyst CB with super-stable Y zeolite containing rare-earth elements B and C that method provided by the invention prepares ₁And CB ₂, CB ₁And CB ₂Composition and physico-chemical property tabulation 2 in.

(3) press (3) hydrothermal aging catalyst CB among the example 5-6 ₁And CB ₂, and estimating its light oil microactivity in the same way, the result is successively shown among Fig. 4 15 and 16.

Table 2

Example number	The catalyst numbering	Contain the rare earth zeolite type	Catalyst is formed, heavy %			Specific surface, rice 2/ gram	Pore volume, milliliter/gram
								Zeolite	Al binder (in aluminium oxide)	Kaolin
			5	C 1	B						30.5	22.4	47.1	250	0.29
6	C 2	C				29.6	23.2	47.2	233	0.26
			Comparative Examples 5	CB 1	D						30.4	22.6	47.0	240	0.25
Comparative Examples 6	CB 2	E				30.1	22.4	47.5	222	0.23

The result of table 2 and Fig. 4 shows, catalyst C ₁And C ₂With reference catalyst CB ₁And CB ₂Unique difference be catalyst C ₁And C ₂Used zeolite is the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention, and reference catalyst CB ₁And CB ₂Used zeolite is not the super-stable Y zeolite containing rare-earth elements that adopts method preparation provided by the invention, under 800 ℃ of situations with 100% water vapour hydrothermal aging different time, contains the catalyst C of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention ₁And C ₂Micro-activity all be higher than the reference catalyst CB that contains the reference zeolite ₁And CB ₂, and, with the prolongation of hydrothermal treatment consists time, reference catalyst CB ₁And CB ₂Active decrease speed is very fast, and contains the catalyst C of the zeolite of method preparation provided by the invention ₁And C ₂Activity descend slower.This further illustrates and adopts the rare earth overstable gamma zeolite that contains of method preparation provided by the invention to have the hydrothermal stability higher than prior art.

Table 3

The feedstock oil title	Straight distillation light diesel oil
		Proportion (d 4 20), gram per centimeter 3	0.8620
Condensation point, ℃	-10
		Carbon residue, heavy %	0.128
S, heavy %	0.855
		Boiling range, the heavy %5 10 30 50 80 90 95 of ℃ initial boiling point does	235 259 266 280 290 308 318 326 337

Example 7-10

Following example illustrates the catalytic performance with the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention.

With catalyst C ₁And C ₂Wore out 4 hours and 17 hours at 800 ℃ respectively.With vacuum gas oil (VGO) shown in the table 4 is the aging rear catalyst C of raw material evaluation ₁And C ₂Catalytic performance.Be reflected on the small stationary bed bioreactor and carry out, reaction temperature is 482 ℃, and weight (hourly) space velocity (WHSV) is 16 hours ^-1, agent weight of oil ratio is 4.The result is as shown in table 5.

Table 4

The feedstock oil title	Vacuum gas oil (VGO)
		Density (20 ℃), gram per centimeter 3	0.8652
Viscosity (50 ℃), millimeter 2/ second	14.58
		Viscosity (100 ℃), millimeter 2/ second	4.37
C 5Insoluble matter, heavy %	0.60
		C 7Insoluble matter, heavy %	0.026
Carbon residue, heavy %	0.04
		Sulfur content, heavy %	0.42
Boiling range, the heavy %5 10 20 30 40 60 80 95 of ℃ initial boiling point does	227 274 289 322 347 373 401 431 458 475

Comparative Examples 7-10

The catalytic performance of following Comparative Examples explanation reference catalyst.

Press the method aging catalyst of example 7-10 and the performance of evaluate catalysts, different is to use catalyst CB ₁And CB ₂Replace catalyst C ₁And C ₂, the result is as shown in table 5.

Table 5

Example number	7	8	9	10	Comparative Examples 7	Comparative Examples 8	Comparative Examples 9	Comparative Examples 10
									Catalyst	C 1Aging 4 hours	C 1Aging 17 hours	C 2Aging 4 hours	C 2Aging 17 hours	CB 1Aging 4 hours	CB 1Aging 17 hours	CB 2Aging 4 hours	CB 2Aging 17 hours
Conversion ratio, heavy %	84.8	72.2	85.5	72.1	83.2	61.8	82.6	62.0
									Yield of light oil, heavy %	81.4	73.0	79.8	71.7	78.6	62.2	77.9	62.0
Product distributes, heavy %
									Gas	14.5	13.8	16.0	14.3	15.8	12.6	16.2	13.0
Gasoline	68.2	56.6	67.5	55.8	65.1	47.3	64.0	47.0
									Diesel oil	13.2	16.4	12.3	15.9	13.5	14.9	13.9	15.5
Heavy oil	2.0	11.4	2.2	12.0	3.3	23.3	3.5	22.5
									Coke	2.1	1.8	2.0	2.0	2.3	1.9	2.4	2.0

Wherein, conversion ratio=gas recovery ratio+yield of gasoline+coking yield; Yield of light oil=yield of gasoline+diesel yield, yield of gasoline=gasoline fraction weight/feedstock oil weight * 100%, the rest may be inferred by analogy, and the boiling range of gasoline is C here ₅-204 ℃, the diesel oil boiling range is 204-330 ℃, and heavy oil refers to boiling point greater than 330 ℃ cut, and gas is C ₅Following cut.

Example 11-12

This example illustrates the catalytic performance of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention.

Press the method for example 1, condition and each material proportioning will contain overstable gamma zeolite, RECl ₃Ground 5 minutes with the slurries of water, obtain containing the slurries of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention, 5.8 kilograms of (dry basis) slurries obtaining and 5.4 kilograms (dry basises) are mixed by the aging boehmite of the described method preparation of example 5-6 and 8.2 kilograms of described kaolin of (dry basis) example 5-6 and deionized water, obtaining a kind of solid content is the slurries of 32 heavy %, with these slurries at 650 ℃ of following spray drying formings, obtain the catalyst microballoon, with the P that contains of pH=3.4 ₂O ₅0.4 80 liters of the ammonium phosphate solutions of heavy % washing 2 times, 120 ℃ of oven dry obtain containing the catalyst C of the super-stable Y zeolite containing rare-earth elements that adopts method preparation provided by the invention ₃, its composition and physico-chemical property are shown in Table 6.

Press the method aging catalyst C of example 7-10 ₃, and evaluate catalysts C ₃The catalytic performance result as shown in table 7.

Example 13-14

This example illustrates the catalytic performance of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention.

Press the method for example 2, condition and each material proportioning will contain overstable gamma zeolite, RECl ₃Ground 5 minutes with the slurries of water, ground again 5 minutes after adding ammoniacal liquor, obtain containing the slurries of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention, the slurries that 5.8 kilograms (dry basises) are obtained and 5.4 kilograms (dry basises) mix by the aging boehmite of the described method preparation of example 5-6 and 8.2 kilograms of described kaolin of (dry basis) example 5-6 and deionized water, obtaining a kind of solid content is the slurries of 28 heavy %, with these slurries at 650 ℃ of following spray drying formings, obtain the catalyst microballoon, use the method washing identical with example 11, drying obtains containing the catalyst C of the super-stable Y zeolite containing rare-earth elements of useful method preparation provided by the invention ₄Catalyst C ₄Composition and physico-chemical property list in the table 6.

Press the method aging catalyst C of example 7-10 ₄, and evaluate catalysts C ₄Catalytic performance, the result is as shown in table 7.

Comparative Examples 11-12

The catalytic performance of this Comparative Examples explanation reference super-stable Y zeolite containing rare-earth elements.

Method by example 11 prepares catalyst, and different just replaces the example 11 described slurries that contain the super-stable Y zeolite containing rare-earth elements of useful method preparation provided by the invention with the slurries before the filtration of Comparative Examples 1 preparation, obtains reference catalyst CB ₃Catalyst CB ₃Composition and physico-chemical property list in the table 6.

Press the method aging catalyst CB of example 7-10 ₃, and evaluate catalysts CB ₃Catalytic performance, evaluation result is listed in the table 7.

Comparative Examples 13-14

The catalytic performance of this Comparative Examples explanation reference super-stable Y zeolite containing rare-earth elements.

Method by example 12 prepares catalyst, and different just replaces the example 12 described slurries that contain the super-stable Y zeolite containing rare-earth elements of useful method preparation provided by the invention with the slurries before the filtration of Comparative Examples 2 preparations, obtains reference catalyst CB ₄Catalyst CB ₄Composition and physico-chemical property list in the table 6.

Press the method aging catalyst CB of example 7-10 ₄And evaluate catalysts CB ₄Catalytic performance, evaluation result is listed in the table 7.

Table 6

Example number	The catalyst numbering	Contain the rare earth zeolite type	Catalyst is formed, heavy %				Specific surface, rice 2/ gram	Pore volume, milliliter/gram
									Zeolite	Binding agent	Kaolin	P 2O 5
			11	C 3	B	29.7							26.5	40.7	3.1	260	0.28
12	C 4	C					29.9	26.8	40.4	2.9	255	0.25
			Comparative Examples 11	CB 3	D	29.8							27.3	40.2	2.7	235	0.27
Comparative Examples 12	CB 4	E					29.7	26.9	40.6	2.8	240	0.28

Table 7

Example number	11	12	13	14	Comparative Examples 11	Comparative Examples 12	Comparative Examples 13	Comparative Examples 14
									Catalyst	C 3Aging 4 hours	C 3Aging 17 hours	C 4Aging 4 hours	C 4Aging 17 hours	CB 3Aging 4 hours	CB 3Aging 17 hours	CB 4Aging 4 hours	CB 4Aging 17 hours
Conversion ratio, heavy %	85.6	74.0	86.5	73.1	83.3	63.3	84.9	63.1
									Yield of light oil, heavy %	80.3	74.9	79.6	73.8	78.4	63.5	78.1	64.9
Product is formed, heavy % casing head gasoling diesel oil heavy oil coke	? ? 15.7 67.9 12.4 2.0 2.0	? ? 13.7 58.4 16.5 9.5 1.9	? ? 16.3 68.1 11.5 2.0 2.1	? ? 13.5 57.8 15.2 11.7 1.8	? ? 16.7 64.3 14.1 2.6 2.3	? ? 13.2 48.0 15.5 21.2 2.1	? ? 17.0 65.7 12.4 2.7 2.2	? ? 12.7 48.4 16.5 20.4 2.0

Example 15

Following example illustrates the anti-sodium pollutant performance of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention.

Take by weighing the catalyst C of 50 gram examples, 13 preparations respectively ₄Be 6 heavy % with concentration respectively, 4 heavy %, this catalyst of NaCl solution impregnation of 2 heavy %, 120 ℃ of oven dry obtain containing sodium oxide molybdena 0.5 heavy %, and 1.0 heavy % and 1.5 weigh the catalyst after the polluting with sodium of %, with the catalyst before and after polluting respectively at 800 ℃ with 100% steam treatment 4 hours, with straight distillation light diesel oil shown in the table 3 is raw material, estimates the light oil microactivity of the catalyst of hydrothermal treatment consists after stain front and back, and reaction unit and condition are with (3) among the example 5-6.Active reservation degree with the variation of sodium content shown among Fig. 5 17.

Comparative Examples 15

The anti-sodium pollutant performance of following Comparative Examples explanation reference zeolite.

Press the method NaCl solution impregnation catalyst of example 15, the light oil microactivity of the catalyst before and after sodium polluted after catalyst was carried out hydrothermal treatment consists and estimates hydrothermal treatment consists, different is that catalyst system therefor is reference catalyst CB ₄, active reservation degree with the variation of sodium content shown among Fig. 5 18.

From the result of Fig. 5 as can be seen, improve reference catalyst CB with the sodium content that pollutes in the catalyst ₄Activity reservation degree descend fast, and contain the catalyst C of the super-stable Y zeolite containing rare-earth elements of method provided by the invention preparation ₄Active reservation degree descends slower, CB ₄And C ₄Difference only be used zeolite and preparation method thereof difference, this has illustrated that the super-stable Y zeolite containing rare-earth elements with method provided by the invention preparation has higher anti-sodium pollutant performance.

Example 16-17

With anti-vanadium performance is example, and the preventing from heavy metal pollution ability of the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention is described.

Take by weighing 2 parts of catalyst C ₃Each 100 gram, mix with 0.9 milligram and 1.8 milligrams of vanadic anhydrides respectively, grind into powder, is smashed to pieces, is sieved and get 20-40 purpose particle compression molding, the particle that obtains was handled 4 hours under 800 ℃ of 100% water vapour atmosphere respectively, obtained catalyst with pollution of vanadium.With straight distillation light diesel oil shown in the table 3 is the micro-activity of raw material evaluation with the catalyst of pollution of vanadium, and compares with the untainted light oil microactivity of handling 4 hours catalyst under 800 ℃ of 100% water vapour atmosphere, obtains light oil microactivity reservation degree.Measure the degree of crystallinity of catalyst mesolite with X-ray diffraction method, and compare, obtain the crystallization reservation degree of zeolite with the degree of crystallinity of untainted catalyst mesolite through department's batten spare hydrothermal treatment consists.The crystallization reservation degree of the content of vanadium in the catalyst, light oil microactivity reservation degree and zeolite is listed in the table 8.

Wherein, light oil microactivity evaluating apparatus and reaction condition are with (3) among the example 5-6.The light oil microactivity of the catalyst of light oil microactivity reservation degree=usefulness pollution of vanadium/through light oil microactivity * 100% of the pollution of vanadium procatalyst of similarity condition hydrothermal treatment consists.The degree of crystallinity of the catalyst mesolite of crystallization of zeolites reservation degree=usefulness pollution of vanadium/through degree of crystallinity * 100% of the pollution of vanadium procatalyst mesolite of similarity condition hydrothermal treatment consists.

Comparative Examples 16-17

With anti-vanadium performance is example, and the preventing from heavy metal pollution ability of reference super-stable Y zeolite containing rare-earth elements is described.

By the method for example 16-17 catalyst is carried out pollution of vanadium, measures the crystallization reservation degree of its light oil microactivity reservation degree and catalyst mesolite, that different is reference catalyst CB ₃Replaced C ₃, the results are shown in Table 8.

Table 8

Example number	Catalyst	Content of vanadium in the catalyst, ppm	Light oil microactivity reservation degree, %	The crystallization reservation degree of zeolite, %
					16	C 3	5000	95	95
17	C 3	10000	90	90
					Comparative Examples 16	CB 3	5000	85	85
Comparative Examples 17	CB 3	10000	76	58

From the result of table 8 as can be seen, after polluting 5000ppm and 10000ppm vanadium, the activity of such catalysts reservation degree of zeolite that contains method provided by the invention preparation is respectively up to 95% and 90%, the crystallization reservation degree of zeolite is also respectively up to 95% and 90%, and after polluting 5000ppm and 10000ppm, the activity of such catalysts reservation degree branch that contains the reference zeolite drops to 85% and 76%, and crystallization reservation degree drops to 85% and 58%.In two kinds of catalyst except that zeolite other component all identical, thereby this difference obviously is because the difference of zeolite causes.This result shows, compared with prior art, adopts the super-stable Y zeolite containing rare-earth elements of method preparation provided by the invention to have stronger preventing from heavy metal pollution ability.

Claims (15)

1. the preparation method of a super-stable Y zeolite containing rare-earth elements, it is characterized in that, this method comprises that the overstable gamma zeolite with the heavy % of sodium oxide content 3-5 mixes with a kind of rare earth compound solution, make a kind of slurries, the slurries that obtain are ground, in described slurries, the weight ratio of overstable gamma zeolite, rare earth compound and water is 1: 0.001-0.5: 1-10, the shear stress of grinding is at least 10 kilograms per centimeter ², milling time is no less than 1 minute.

2. method according to claim 1 is characterized in that, the shear stress of described grinding is the 10-100 kilograms per centimeter ²

3. method according to claim 2 is characterized in that, the shear stress of described grinding is the 10-50 kilograms per centimeter ²

4. method according to claim 1 is characterized in that, described milling time is 1-15 minute.

5. method according to claim 1 is characterized in that, described milling time is 2-10 minute.

6. method according to claim 1 is characterized in that, the weight ratio of described overstable gamma zeolite, rare earth compound and water is 1: 0.05-0.3: 1-4.5.

7. according to claim 1 or 6 described methods, it is characterized in that described rare earth compound is selected from the chloride and/or the nitrate of rare earth.

8. method according to claim 7 is characterized in that described rare earth compound is selected from the chloride of rare earth.

9. method according to claim 1 is characterized in that described rare earth is selected from one or more in lanthanum, cerium, lanthanum rich mischmetal and the cerium-rich mischmetal.

10. method according to claim 9, tool are characterised in that described rare earth is selected from lanthanum rich mischmetal or cerium-rich mischmetal.

11. method according to claim 1 is characterized in that this method also further is included in a kind of alkaline solution of adding in the grinding slurries afterwards, makes the pH value of slurries rise to 5-10, and continues to grind at least one minute.

12. method according to claim 11 is characterized in that, behind the adding alkaline solution, the pH value of described slurries is 6-8.

13. method according to claim 11 is characterized in that, described alkaline solution refers to ammonia spirit.

14. method according to claim 11 is characterized in that, behind the adding alkaline solution, the time of continuing to grind is 1-15 minute.

15. method according to claim 14 is characterized in that, behind the adding alkaline solution, the time of continuing to grind is 2-10 minute.

Images