DE2617571A1 - PROCESS FOR MANUFACTURING ZEOLITHES WITH HIGH SILICON OXIDE-ALUMINUM OXIDE RATIO - Google Patents

Description

UEXKÜLL & STOLBERG PATENTANWÄLTE

2 HAMBURG 52

BESELERSTRASSE 4

DR. J.-D. FRHR. by UEXKÜLL

DR. ULRICH GRAF STOLBERG DIPL-ING. JÜRGEN SUCHANTKE

W.R. Grace & Co. (priority: April 24, 1975,

Gr ^ ce Plaza ¹⁶ ' ^{May 1975}

1114 Avenue of the Americas US 571 177, US 578

New York, NY 10036 / V.St.A. _ _13O65)

Hamburg, April 21, 1976

Process for making high silica: alumina ratio zeolites

The invention relates to a method for treating faujasite zeolites to obtain a zeolite with a high silica to alumina molar ratio.

For some time now, zeolitic aluminosilicates have been used in the catalytic cracking of hydrocarbons known. Faujasite, which are crystalline aluminosilicates with an alkali metal, which form the structure of the mineral Faujasite and having a molar ratio of silica to alumina of about 3: 1 to 6: 1 are particularly popular used as cracking catalysts. These zeolites are usually mixed with a matrix material, which is for example silica-alumina, clay (both

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acid bleached as well as calcined), bauxite or silicon oxide-magnesium oxide compositions can act. Usually the catalyst contains about 5 to 50% of the faujasite Aluminosilicate, the rest consists of matrix material.

The introduction of these zeolite-reinforced catalysts meant a great improvement in the art of catalytic Cracking. The presence of as little as 5% of the zeolite in a matrix material resulted both a very marked improvement in conversion and a considerable decrease in the percentage Proportion of such hydrocarbons which in the cracking reaction to undesired products, such as Carbon.

The crystalline aluminosilicates are remarkable substances in that they are physically and chemically Means can be modified considerably without their basic crystalline character being destroyed. One of these Modifications is the increase in the silica to alumina ratio by removing aluminum from the crystal structure. In US-PS 3,640,681 to Pickert a process of this type is described in which the Aluminum framework made from the crystalline zeolite molecular sieves is extracted using acetylacetone as the extractant. In U.S. Patent 3,442,795 to Kerr there is a Process for increasing the silicon oxide

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Ratio of these zeolites by treating the aluminosilicates explained with a complexing agent in which the aluminum is complex-bound in such a form which facilitates the separation of the aluminum from the aluminosilicates.

The applicant has now found that a zeolite with a ratio of silicon oxide to aluminum oxide of more than 7: 1 and up to about 20: 1, which has a high degree of stability and a relatively low ion exchange capacity has, by treating a faujasite zeolite with a silica to alumina ratio of about 3.5 to 6 with a dilute mineral acid. In the process according to the invention, the faujasite zeolite is subjected to an ion exchange treatment before this acid treatment subject, and thereby the Na_O content is reduced, and it is carried out in at least one stage at at least one high temperature, advantageously at one temperature calcined at more than 535 ° C for a period of about 0.1 to 10 hours.

In the first process stage of the process according to the invention the ion-exchange-treated zeolite is produced in the second stage of the process according to the invention is acid treated. The faujasite aluminosilicates described in U.S. Patents 3,293,192, 3,402,996, 3,449,070 and 3,595,611 are products that are in at least one

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Stabilization stage have been heat set at at least one high temperature. It is important that as zeolite material, which is acid-treated according to the invention, a stabilized faujasite, for example one of these in the mentioned US-PS described materials can be used. The stabilization of the zeolite is seen in itself a processing stage known to the person skilled in the art, and the products obtained in such a stage must be used as starting material are used for the production of high silicon oxide zeolites according to the invention.

The faujasite described in U.S. Patent 3,293,192 is designated Z 14 US. One puts this product through successively Ion exchange treatment of a silica to alumina ratio of from about 3.5 to 6 Faujasite with an ammonium salt (or a complex amine salt, from which, after calcination, an ammonium ion is converted into the zeolite remains) until the alkali content is reduced to 5%. After that, the product is at a temperature calcined from about 535 to 820 ° C for a period of about 0.1 to 10 hours. Then the Cooled mass and successively ion exchange treatment with an ammonium (or complex amine) salt solution until the alkali content is reduced to less than 1% by weight. Thereafter, the zeolite is at 535 to 820 ° C calcined for a period of 0.1 to 10 hours.

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The zeolite material described in U.S. Patent 3,402,996 is referred to as CREY. This zeolite is put through Exchange treatment of a faujasite having a silica to alumina ratio of about 3.5 to 6 with a salt solution of the particular cation that one wishes to exchange, such as salts of rarer Earth, here. In this exchange treatment, the Na ^ O content of the zeolite reduced to less than 4%. After that, the zeolite is used to remove excess salts washed, then dried and at a temperature of about 315 to 650 ° C for a period of about 0.1 calcined for up to 3 hours. The zeolite is then cooled and treated with a suitable salt solution, for example exchanged from ammonium salts, rare earth salts, alkaline earth salts and the like. To the Finally, the zeolite is washed out well.

The zeolite material described in U.S. Patent 3,449,070 is designated Z 14 U.S. Type II. This zeolite wins by exchange treatment of the silica to alumina ratio of about 3.5 to 7 faujasitic aluminosilicate with an ammonium salt, Amine salt or the like to reduce the alkali content to about 2.5 to 4%. Then will the product is filtered, dried and calcined at a temperature of at least 650.degree. After that the product cooled and exchanged with a salt solution

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clelt. This exchange treatment can reduce the content of the product to less than 1 % .

The zeolite described in US Pat. No. 3,595,611 is referred to as PCY. This zeolite is produced by a combined ammonium ion exchange treatment and metal ion exchange treatment of a faujasite with a silicon oxide: aluminum oxide ratio of about 3.5 to 5. First, the zeolite is exchanged with an ammonium salt solution; the Na ₂ O content is reduced to about 2.5 to 3.5%. The zeolite is then filtered and the cake returned to a brine solution containing a rare earth metal or other cation in sufficient quantity to provide 0.5 to 15% rare earth oxide or the equivalent thereof other cations can be released to the zeolite. The product is then filtered, washed free of excess salt and heated to a temperature of about 370 to 870.degree. Finally, the product is cooled and exchanged with an ammonium salt solution or some other metal cation solution, _{reducing the Na 2} O content to less than 1%.

The operation of any of the patents cited above is useful as a first step in the process of the present invention Procedure. The zeolites produced by this procedure are characterized by the fact that they are stable to

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thermal treatment up to 900 ° C. A significant amount of surface area remains after such treatment.

The following process step in the process according to the invention is the removal of the aluminum ions from the stabilized zeolite. This removal is achieved by bringing the stabilized zeolite into contact with an acidic solution having a pH of less than 4. Usually at least 0.5 gram equivalents of acid are used for every gram atom of aluminum in the stabilized zeolite. Any of the strong mineral acids such as hydrochloric acid, nitric acid, sulfuric acid and the like can be used for this treatment. The treatment is carried out until at least 15% of the aluminum ions are removed from the zeolite structure. This removal allows the molar ratio of silicon oxide to aluminum oxide to be increased from a value in the range from 3.5: 1 to 5: 1 to a value in the range from 7: 1 to about 20: 1, depending on the duration of the treatment and the amount of acid used. After this treatment, the zeolite is washed and dried, and then the product is recovered. This product is characterized by a Na ₂ O content of less than 0.3%. The basic cell of the zeolite has a size of about 24.20 A * to about 24.60 A. After the aluminum has been removed, the surface area of the product is about 500 to 10000 m ² / g.

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Preferably that made according to the present invention is high Siliciumoxidhaltxge zeolite built into a composite catalyst through coordination with a matrix material.

Before installation in the composite catalyst, rare earth metal cations can be removed by ion exchange treatment or other cations are introduced into the zeolite which has been partially freed from aluminum. As a result of the low Ion exchange capacity is the amount of rare earth or other ions in the zeolite relative low. It is generally in the order of 1 to 10%, based on the dry weight.

In this process stage, other cations, e.g. magnesium, can be used instead of the rare earth metal cations will.

In a preferred embodiment of the invention The zeolite, in the cation form with rare earths or other cations, is used in the subsequent process Process stage distributed in an inorganic oxide matrix, so that the zeolite crystals within suspended throughout the matrix and completely distributed therein. The usual matrix material is Silicon oxide, particularly advantageously used in combination with another oxide. The crystal-matrix suspension can be easily achieved by dispersing

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Yeasting of the zeolite in a suitable sol of silicon material and gelation of the sol can be prepared in numerous ways. The zeolite can also be dispersed in a cogel composed of silicon oxide and an oxide of a metal. Examples of suitable cogels are silica-alumina, silica-magnesia, silica-zirconia, Silica-titania and also triple combinations, such as silica-alumina-zirconia, Silica-alumina-magnesia and silica-magnesia-zirconia. The preferred cogels used include silica-alumina and silica-magnesia, and of these, silica-alumina is particularly advantageous. In addition, the matrix material a considerable amount of clay added to the sodium silicate solution before the formation of the cogel with the aluminum oxide, Magnesium oxide, etc. added.

These gels and cogels generally constitute the major constituent of the silica and a minor proportion of the or the other oxides. The silicon oxide content in the silicon-containing gel or cogel matrix is generally more than 55% by weight, preferably 60 to 90% by weight, and the proportion of the other oxide is in the range of 5 to 45% by weight, preferably 10 to 40% by weight.

If clay is present as a component of the matrix material, this substance is only present in an amount of 10 to 70%.

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The silica-alumina hydrogels can be used after each the methods known for this. For example, a water-containing precipitate of silicon oxide can be used by mixing a solution of sodium silicate with an acid such as sulfuric acid, or with Carbon dioxide and preparing a slurry with a pH below 9, usually below 7. It Then, to the liquid containing the hydrous precipitate, a solution of an aluminum salt such as Aluminum sulfate, added, and the pH of the mixture is adjusted by adding an alkali, for example ammonia, set to about 4 so that the alumina will precipitate. A further component can be included in the matrix natural or synthetic clay, such as kaolin clays, montmorillonite, bentonite, halloysite and the like to be available.

The zeolite matrix composition is prepared by intimately mixing the zeolite described above with the silicon oxide-containing one Hydrogel, clay or mixture of these substances and then receives a composite product, the zeolite component uniformly distributed in the inorganic oxide matrix and suspended therein.

The zeolite component is usually in the catalyst in an amount of 5 to 50%, preferably about 10 to 30%.

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example 1

A 100 g sample of a zeolite called PCY was prepared according to the method described in US Pat. No. 3,595,611. The product had an Na ₂ O content of less than 1%. It was produced by thermal stabilization at a temperature of 76O ° C. The thermally stabilized zeolite was treated with a dilute (0.1) normal solution of nitric acid at a temperature of 30 ° C. for a period of 4 hours. The zeolite was filtered and treated again with nitric acid. A total of 0.75 moles of nitric acid was used in this experiment. The zeolite was then collected, washed free of dissolved salts and dried.

The properties of the zeolite before and after the treatment are given in Table I below.

Surface area of basic cell aluminum oxide silicon oxide SiO ₂ / Al ₂ O ₃ ratio

Re ₂ O ₃

Na ₂ O

Percent of aluminum removed

Table I. /G of aluminum
exempted PCY PCY 8th 940 m ² / g 800 m ² 24.39 8 24.65 12.6% 21% 83.2% 66% 11.2 5.3 1.5 0.0 less than 0.2% 13%

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From the above data it is evident that there is no loss of surface area even though the ratio of Increased silica to alumina in the zeolite from 5.3 to 11.2 and removed 52% of the aluminum atoms.

Example 2

This example illustrates the manufacture of the zeolite using a Z 14 US as the starting material.

Based on a faujasite in the sodium form having a silica to alumina ratio of about 5 was prepared according to that described in U.S. Patent 3,293,192 Method of working a sample of Z 14 US produced. The Z 14 US product had the following characteristics:

Table II

Na ₂ O 0.2%

Al ₂ O ₃ 25.4%

SiO ₂ 74.4% SiO ₂ / Al ₂ O ₃ ratio 5.0

Basic cell 24.34 S.

Surface area 780 m / g

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An amount of the equivalent to 50 g dry basis was used

Z 14 US zeolite, which had a surface area of 780 m / g and a silica to alumina ratio of 5, was slurried with 500 g of water at room temperature, and 15 g of concentrated nitric acid (70.3% HNO ₃ ) were diluted with water to 500 ml diluted. The acid solution was slowly added dropwise to the slurried zeolite with vigorous stirring over a period of 16 hours. A total of 0.166 moles of nitric acid was used in this treatment. The zeolite was then collected, washed free of dissolved salts and dried. The properties of the zeolite are summarized in the table below.

Table III

Na ₂ O 0.12%

Al ₃ O ₃ 18.7%

SiO ₂ 81.2%

Crystallinity good

2 surface area 790 m / g

SiO ₂ / Al ₂ O ₃ ratio 7.4

Percent Al Removed 25% of the total Al.

From this data it can be seen that by increasing the silica / alumina ratio from 5 to 7.4 and removal of 25% of the aluminum atoms resulted in no loss of surface area or crystallinity.

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Example 3

In this example, a more concentrated nitric acid was used for the aluminum removal reaction used.

There was a 50 g amount of a Z 14 US product corresponding to that used in Example 2, a

2
Surface area of 780 m / g and a silica / alumina ratio of about 5 was used as the starting material. The zeolite was slurried in 500 ml of water and 30 g of concentrated nitric acid (70.3% nitric acid) diluted to 500 ml was slowly added over a 16 hour period. After this period of time, the zeolite was filtered off and washed free of dissolved salts. The characteristics of this product are given in Table IV below.

Table IV

Na ₂ O 0.15%

Al ₂ O ₃ 13.2%

SiO ₂ 86.6%

Crystallinity good

Surface area 750 m / g

SiO ₂ / Al ₂ O ₃ ratio 7.4

Percent Al 50 Removed

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From the data presented it can be seen that the ratio of silica to alumina went from 5.0 to 7.4 increased and approximately 50% of the aluminum atoms could be removed without a significant loss of crystallinity or surface occurred.

Example 4

In this example, a Z 14 US zeolite was used as the starting material used, which had been prepared by the process described in US Pat. No. 3,449,070.

The alkali-free zeolite was prepared by exchanging a quantity of 500 g of a faujasite having a silica: alumina ratio of about 5 by means of three separate exchanging treatments with ammonium sulphate at proportions of zeolite to sulphate to water such as 1: 1:10. The recovered product was washed and calcined at 788 ° C. for 3 hours. The calcined product contained about 3% Na ₃ O. It was found to be

2 has a surface area of 775 m / g after calcination would have.

A 100 g quantity of the alkali-depleted zeolite was slurried with 500 ml of water. It became focused Nitric acid (50 g) diluted to 500 ml, and this solution became the zeolite

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slurry added. The zeolite was then filtered off and washed until it was free of dissolved salt. The characteristics of the product are shown below Table compiled:

Table V

Na ₂ O 0.73%

Al ₃ O ₃ 12.5%

SiO ₂ 86.8%

Crystallinity good

Surface area 715 m / g

From this data it can be seen that the surface area of the product does not decrease significantly even if a more concentrated nitric acid solution is used in the removal of the aluminum from the Z 14 US material. During this treatment, the Na ₃ O concentration was reduced from about 3 to about 0.73%.

Example 5

In this example, the Z 14 US- manufactured according to the method described in Example 4 was used as the starting material.

2 zeolite with a surface area of 775 m / g is used. 100 g of the zeolite was slurried in 500 ml of water.

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Concentrated nitric acid (25 g) were made up with water 500 ml and the resulting diluted solution slowly added to it over a 16 hour period Slurry of the zeolite added. The zeolite was then filtered off and washed until it dissolved Salt was free. The characteristics of this product are summarized in the following table VI:

Table VI

O 0.94%

₂ O ₃ 17.8%

SiO ₂ 81.3%

Crystallinity good

Surface area 730 m / g

It can be seen from these data that when a less concentrated nitric acid is used to remove the aluminum, the Na ₂ O concentration is reduced to about 1/3 and the product has a larger surface area than when a more concentrated nitric acid was used.

Example 6

Through a combined ammonium exchange and metal ion exchange treatment a faujasite having a silica / alumina ratio of about 3.5 to 5

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a zeolite designated PCY as described in U.S. Patent 3,595,611. The zeolite was first exchanged with an ammonium salt solution, during which the Na — O content was reduced to about 2.5 to 3.5%. The zeolite was then filtered and the filter cake returned to a salt solution containing rare earths or other cations in an amount sufficient to provide 0.5 to 15% rare earth oxides or the equivalent amount of the other cations for the zeolite. The product was then filtered, washed free of excess salt and heated at a temperature of about 370 to 870 ° C. The product was then cooled and _{exchanged with an ammonium salt solution in order to reduce the Na 2} O content to less than 1%.

100 g of this zeolite was treated with a dilute (0.1) normal solution of nitric acid for 4 hours at a temperature of 30 ° C. The zeolite was filtered and treated again with nitric acid. A total of 0.75 moles of nitric acid was used in this treatment. The zeolite obtained afterwards was washed free of dissolved salts and dried. The analysis of the zeolite gave the following values in% by weight: Na ₃ O less than 0.2; SiO ₃ 83.2; Al ₃ O ₃ 12.6; Rare earth oxides 1.5.

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By dry mixing the zeolite with a semi-synthetic one commercially available cracking catalyst, which had a low activity, the zeolite was known as Processed catalyst component. The semi-synthetic catalyst contained 60% silica / alumina and 40% clay. The physical mixture of these two components was formed into tablets, and the catalytic one Activity was determined by means of a microactivity test. In this experiment the to be examined Samples are placed in a reaction vessel and in the presence of a West Texas gas oil feed heated to a temperature of 482 ° C. The catalyst: oil ratio was 5.88 and it was run at an hourly rate Weight throughput of 16 driven. In this attempt the one produced with 10% of the zeolite produced according to the invention (0.1% oxides of rare earths) Catalyst, referred to as Catalyst C, with a semi-synthetic catalyst that did not contain zeolite and which is designated with catalyst A, and with a catalyst that contains 10% particularly stable faujasite (PCY) and designated as Catalyst B is compared. Those determined in the test series Data are summarized in Table VII below.

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Tabel VII C. catalyst A. B. 61.54 Sales in% by volume 29.08 46.82 0.059 H ₂ wt.% 0.054 0.045 0.146 C ₁ % by weight 0.099 0.092 0.211 C ₂ % by weight 0.104 0.060 0.88 C ₃ vol.% 0.36 0.44 11.7 C ₄ vol.% 7, 70 9.34 52.16 C ₅ + (gasoline) vol.% 21.90 38.64 1.42 Coke weight% 1.36 1.14

Example 7

An experiment was carried out in which the amount of rare earth metal oxide in the zeolite by additional Exchange with rare earths was increased.

25 g of the acid-treated zeolite described in Example 1 were mixed with an aqueous solution of a rare earth metal chloride containing 10 g of rare earth metal chloride (as RE ₃ O ₃ ) per 100 ml, with a zeolite: rare earths: water ratio of 1 : 1:10 exchanged. The exchange treatment was carried out at a temperature of about 90 ° C. for 30 minutes. The zeolite was washed until free of dissolved salt and dried. The analysis of the zeolite gave the following values, in% by weight: Na ₃ O - 0.1; Rare earth oxide - 7.1;

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Alumina - 10.2; Silica - 82.6. It was made from 10% of the zeolite and 90% of the commercially available semi-synthetic Cracking catalyst of low activity prepared a physical mixture and added this mixture Molded tablets. The microactivity of this catalyst (designated as Catalyst D) was compared to the im Example 6 compared catalyst B described. The results of this comparative study are shown below Table VIII compiled:

Table VIII D. catalyst B. 71.93 Sales in% by volume 46.82 0.052 H ₂ wt.% 0.045 0.243 C ₁ % by weight 0.092 0.260 C ₂ % by weight 0.060 1.22 C ₃ vol.% 0.44 12.72 C ₄ vol.% 9.34 60.56 C ₅ + gasoline% by volume 38.64 1.89 Coke weight% 1.14

It can be seen from this data that the conversion results are greatly improved and remarkable Increases in gasoline yield can be obtained when the amount of rare earths in the zeolite is increased is.

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Example 8

In this example, the product of Example 6 underwent an additional exchange treatment with a magnesium chloride solution subjected.

25 g of the zeolite were exchanged with a magnesium chloride solution containing 10 g of magnesium chloride per 100 ml. The zeolite: magnesium chloride: water ratio was 1: 1:10. The zeolite was washed free of excess salt and dried. The analysis of the zeolite gave the following values, in% by weight: Na ₃ O -1, O; RE ₃ O ₃ - 1.5; Al ₂ O ₃ - 10.4; SiO ₃ - 87; MgO - 1.0. A catalyst was made by physically blending 10% of the zeolite and 90% of the commercially available low activity semi-synthetic cracking catalyst. The mixture was molded into tablets, and the microactivity test was carried out under the same conditions as in Example 6. The product of this run was named Catalyst E and compared to Catalyst B of Example 6. The values obtained during this investigation are compiled in the following table:

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Table IX B. E. catalyst 46.82 71.68 Sales in% by volume 0.045 0.062 H ₂ wt.% 0.092 0.195 C ₁ % by weight 0.060 0.253 C ₂ % by weight 0.44 1.27 C ₃ vol.% 9.34 12.76 C ₄ vol.% 38.64 60.43 C ₅ + gasoline% by volume 1.14 1.39 Coke weight%

It can be seen from these values that a catalyst containing as little as 0.1% of magnesium is excellent Brings conversion results. ...-- '

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Claims (11)

2 61 7 S 7 Claims i) Method of treating a faujasite zeolite with a molar ratio of silica-alumina in the range of 3.5: 1 to 6: 1 to increase this silica: alumina ratio to a value in the range from 7: 1 to 20: 1, characterized in that (a) Subjecting the faujasitic zeolite to an ion exchange treatment and thereby alkali cations removed, then calcined in at least one stage at at least one high temperature, and then (b) Treating the ion-exchanged and calcined faujasite with a dilute mineral acid and thereby removing at least 15% of the aluminum atoms from the structure. 2. The method according to claim 1, characterized in that in process step (a) the faujasite is stabilized by exchange treatment with ammonium ions and the Na ₂ O content is reduced to 3 to 4%, for about 0.1 to 3 hours at about 535 C, exchanged with ammonium ions and the Na ₃ O content reduced to less than 1% and calcined at a temperature of about 820 ° C. 609846/0997 3. The method according to claim 1, characterized in that in process step (a) the faujasite is stabilized by exchange treatment with a solution containing rare earth metal ions and the Na ₂ O content is reduced to about 3%, at about 315 to 650 ° C calcined, exchanged with ammonium ions and thereby _{reduced the Na 2} O content to less than 1% and calcined at 370 to 820 ° C. 4. The method according to claim 1, characterized in that in process step (a) the faujasite is stabilized by exchange _{treatment with ammonium ions and the Na 2} O content is reduced to about 2.5 to 4.0% and then at 76O ° C calcined. 5. The method according to claim 1 to 4, characterized in that in process step (b) as the mineral acid Nitric acid, sulfuric acid or hydrochloric acid with a concentration of about 0.1 η to 1 η is used. 6. The method according to any one of the preceding claims, characterized in that the acid treatment during for about 0.25 to 24 hours at a temperature of about 20 to 50 ° C. 7. The method according to any one of the preceding claims, characterized in that the acid-treated 609846/0997 Zeolite together with a matrix material containing an inorganic oxide to form a composite cracking catalyst processed. 8. The method according to claim 7, characterized in that the acid-treated zeolite is subjected to a rare earth ion exchange treatment before combined it with the matrix material. 9. The method according to claim 7 or 8, characterized in that the matrix material is silicon oxide, aluminum oxide, Silica-alumina, silica-magnesia or clay-containing silica-alumina is used. 10. composite catalyst for cracking hydrocarbons, characterized in that it consists of an inorganic one Oxide-containing matrix material consists in which a zeolite with an alkali oxide content of less than 1% and a silica: alumina molar ratio ranging from 7: 1 to 20: 1. 11. Use of a catalyst according to claim 10 or of a catalyst prepared according to one of claims 7 to 9 for cracking high-boiling hydrocarbons into lower-boiling hydrocarbons. 609846/0997