CA1074284A - Chemical process - Google Patents
Chemical processInfo
- Publication number
- CA1074284A CA1074284A CA277,129A CA277129A CA1074284A CA 1074284 A CA1074284 A CA 1074284A CA 277129 A CA277129 A CA 277129A CA 1074284 A CA1074284 A CA 1074284A
- Authority
- CA
- Canada
- Prior art keywords
- zeolite
- product
- metakaolin
- temperature
- hours
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/20—Silicates
- C01B33/26—Aluminium-containing silicates, i.e. silico-aluminates
- C01B33/28—Base exchange silicates, e.g. zeolites
- C01B33/2807—Zeolitic silicoaluminates with a tridimensional crystalline structure possessing molecular sieve properties; Isomorphous compounds wherein a part of the aluminium ore of the silicon present may be replaced by other elements such as gallium, germanium, phosphorus; Preparation of zeolitic molecular sieves from molecular sieves of another type or from preformed reacting mixtures
- C01B33/2815—Zeolitic silicoaluminates with a tridimensional crystalline structure possessing molecular sieve properties; Isomorphous compounds wherein a part of the aluminium ore of the silicon present may be replaced by other elements such as gallium, germanium, phosphorus; Preparation of zeolitic molecular sieves from molecular sieves of another type or from preformed reacting mixtures of type A (UNION CARBIDE trade name; corresponds to GRACE's types Z-12 or Z-12L)
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
Abstract
PROCESS FOR ZEOLITE A
Abstract An improved process is described for the production of zeolite by reacting metakaolin with sodium hydroxide solution at conditions which permit a single stage operation with a reduced processing time as contrasted with prior methods.
Abstract An improved process is described for the production of zeolite by reacting metakaolin with sodium hydroxide solution at conditions which permit a single stage operation with a reduced processing time as contrasted with prior methods.
Description
~0~284 This invention relates to the preparation of zeolite A
which is a synthetic three-dimensional crystalline zeolite of the molecular sieve type. More particularly, an improved and more efficient process is provided.
Description of the Prior Art :, The properties, formula and preparation of zeolite A
are well known being described for example in U. S. Patent 3,114,603, and in U. S. Patent 3,119,659. The references cited in both patents are also of interest.
According to the process of U. S. Patent 3,114,603, synthetic zeolite A is prepared in a two-step process wherein the reactants are combined and digested at a temperature of 20-55C for a period of at least 2 hours in a first step which is followed by a second step of heating at at least 75C for a prolonged period. In general, the preferred total time required for the two steps in the examples of U. S. Patent 3,114,603 ranges from 7.5 to 48 hours.
Summary of the Invention The process of the present invention comprises producing sodium zeolite A by reacting metakaolin and NaOH in an aqueous solution at a temperature of from about 70 to about 100 Cfor from about 1 hour to about 15 hours although reaction periods considerably shorter are preferred. Preferably the temperature is from about 80 to about 85C, especially about 85C. Preferably the metakaolin, water and NaOH are used in lO'f'4Z~4 ratios of zeolite A product, the mol ratio of H2O/Na2O in the system being from about 15 to about 200, preferably f.rom about 25 to about 50, and typically 40.
Description of the Preferred Embodiments Zeolite A is represented by the formula:
1.0 + 0.2 Na20:A1203:2.0 + 0.5 SiO2:YH2O
wherein Y may have any value up to about 5.1.
A preferred zeolite is represented in Belgian Patent 814,874 by the formula:
Nal2(Alo2-sio2)l2 xH2o wherein x is a number in the region of 20 to 30, preferably about 27. Such are the compositions desired to be produced by the process of the present invention.
From prior art such as U. S. Patent 3,114,603, it is known that one way the foregoing zeolites can be prepared is by reacting metakaolin and NaOH in aqueous solution;
however, such prior art processing utilizes a two-step process for high purity product (above about 80 percent zeolite A purity) wherein the reactants are combined and digested at room temperature (20-25C) for several hours and then the temperature is raised to a temperature in the region of 75 to 110C for a prolonged crystallization operation. Apparently the prior art teaches - ' ' ~ : - . : -~.
~.~
," 107~2~ .
that the two step operation is required to avoid or minimize the presence in ~e product ~f by-products or contaminants such as other zeolites, hydroxy sodalite or amorphous substances.
In contrast to the foregoing, it has been found that a single step process is possible using a reaction time of the order of two to four hours and that with such shortened time one step processing, zeolite A product purity of 90 percent or better are readily obtained. It will be appreciated that the present discovery makes it possible to simplify the design of plants used to produce zeolite A, such simplification being reflected in lower cost product. The present inventors have found, for example, that a reaction time of 2 hours at 85C is adequate to achieve substantially complete reactions to a final product purity of 9S percent or higher.
Product thus obtained is readily recovered by filtering or centrifuging following which the recovered product is washed to remove residual mother liquor and impurities. Washed product is then subjected to drying to remove residual water.
Although mother liquor removed from the product as well as the washwater may be recycled wholly or in part to the reaction step for combination with fresh fed reactants, such generally is less preferred than performing one or more additional crystallizations to recover the product value contained therein.
With such preferred processing, the present process forms a water solution of NaOH and reacts that with metakaolin rather than forming an aqueous NaOH solution containing recycle mother liquor for the reaction with metakaolin.
Of course, it is evident that the present process does not require the exclusion of recycle mother liquor and washings from the reaction system and that under appropriate cm/
- 1074~
conditions such recycle may be advantageous. It is also evident that total recycle of the mother liquor is not usually desired in such systems since the purge of a portion of the recycle stream is usually desirable to avoid the build-up of impurities.
The present process utilizes the meta form of amorphous kaolin, called metakaolin, or the equivalent, prefer-ably produced by the calcination of kaolin at a temperature of from about 550 to about 900C. Such calcination is well known in the art and need not be discussed in greater detail here since it appears in U.S. Patent 3,114,603. As explained in U.S. Patent 3,114,603, it is usually desired to avoid prolonged time delay between the calcination of the feed kaolin and its use in the present process.
The following examples indicate preferred embodi-ments and aspects of the present invention.
250 grams H20 was added to a l-liter round bottom flask equipped with a heating mantla and an agitator at room temperature. 34.5 grams of NaOH beads was then added and the mixture was stirred until the NaOH was dissolved. 40 grams of metakaolin was added and the mixture was heated to 85C. The flask and contents was held at 85C for 2 hours while stirring.
The heating mantle was removed and the contents of the flask filtered with a Buchner funnel to recover the solid product. The product was washed with 500 grams of water and oven dried at 100C for 5 hours or more.
~ sample of the product was analyzed by X-ray diffraction and found to be 95 percent or higher zeolite A
(ASTM X-ray powder diffraction pattern File Card No. 11-590).
The mol ratios of the foregolng example are:
cm~ ' ' 10'74~
Na20/A1203 -= 2 .
SiO2/A1203 = 2 H20/A1203 = 78 H20/Na20 = 39 EXAMPLE I I :
Example I was repeated using 125 grams of water instead of 250 grams and a temperature of 80C instead of 85C.
Similar results were obtained. The H20/Na20 ratio was 20.
EXAMPLE I I I
153 gallons of deionized water was added to a steam jacketed, stirred, 250 gallon reactor. 184 pounds of sodium hydroxide beads was then added to the reactor. The mixture was heated to 179C and agitated until the beads dissolved.
Then 20~ pounds of metakaolin was added to the reactor and the temperature was increased to 185F (85C). This temperature was held 2-1/2 hours while the mixture was agitated. The reaction mass was cooled to approximately room temperature and discharged in four batches into a centrifuge for removal of the supernatant liquor. The centrifuge cake was washed with 262 gallons of deionized water. 286 lbs of zeolite A was recovered. The product was essentially 100 percent zeolite A as determined by X-ray diffraction.
Example I was repeated in a series of runs under various conditions. Results are tabulated with the results of Examples I and II included as Runs I and II, respectively.
cm/
1074~4 Q~ I
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N
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_ ~15 h ~ ~t ~ ~ ~t -0~ O O O O O O O
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H H H
I ~ ~ X X X X X
which is a synthetic three-dimensional crystalline zeolite of the molecular sieve type. More particularly, an improved and more efficient process is provided.
Description of the Prior Art :, The properties, formula and preparation of zeolite A
are well known being described for example in U. S. Patent 3,114,603, and in U. S. Patent 3,119,659. The references cited in both patents are also of interest.
According to the process of U. S. Patent 3,114,603, synthetic zeolite A is prepared in a two-step process wherein the reactants are combined and digested at a temperature of 20-55C for a period of at least 2 hours in a first step which is followed by a second step of heating at at least 75C for a prolonged period. In general, the preferred total time required for the two steps in the examples of U. S. Patent 3,114,603 ranges from 7.5 to 48 hours.
Summary of the Invention The process of the present invention comprises producing sodium zeolite A by reacting metakaolin and NaOH in an aqueous solution at a temperature of from about 70 to about 100 Cfor from about 1 hour to about 15 hours although reaction periods considerably shorter are preferred. Preferably the temperature is from about 80 to about 85C, especially about 85C. Preferably the metakaolin, water and NaOH are used in lO'f'4Z~4 ratios of zeolite A product, the mol ratio of H2O/Na2O in the system being from about 15 to about 200, preferably f.rom about 25 to about 50, and typically 40.
Description of the Preferred Embodiments Zeolite A is represented by the formula:
1.0 + 0.2 Na20:A1203:2.0 + 0.5 SiO2:YH2O
wherein Y may have any value up to about 5.1.
A preferred zeolite is represented in Belgian Patent 814,874 by the formula:
Nal2(Alo2-sio2)l2 xH2o wherein x is a number in the region of 20 to 30, preferably about 27. Such are the compositions desired to be produced by the process of the present invention.
From prior art such as U. S. Patent 3,114,603, it is known that one way the foregoing zeolites can be prepared is by reacting metakaolin and NaOH in aqueous solution;
however, such prior art processing utilizes a two-step process for high purity product (above about 80 percent zeolite A purity) wherein the reactants are combined and digested at room temperature (20-25C) for several hours and then the temperature is raised to a temperature in the region of 75 to 110C for a prolonged crystallization operation. Apparently the prior art teaches - ' ' ~ : - . : -~.
~.~
," 107~2~ .
that the two step operation is required to avoid or minimize the presence in ~e product ~f by-products or contaminants such as other zeolites, hydroxy sodalite or amorphous substances.
In contrast to the foregoing, it has been found that a single step process is possible using a reaction time of the order of two to four hours and that with such shortened time one step processing, zeolite A product purity of 90 percent or better are readily obtained. It will be appreciated that the present discovery makes it possible to simplify the design of plants used to produce zeolite A, such simplification being reflected in lower cost product. The present inventors have found, for example, that a reaction time of 2 hours at 85C is adequate to achieve substantially complete reactions to a final product purity of 9S percent or higher.
Product thus obtained is readily recovered by filtering or centrifuging following which the recovered product is washed to remove residual mother liquor and impurities. Washed product is then subjected to drying to remove residual water.
Although mother liquor removed from the product as well as the washwater may be recycled wholly or in part to the reaction step for combination with fresh fed reactants, such generally is less preferred than performing one or more additional crystallizations to recover the product value contained therein.
With such preferred processing, the present process forms a water solution of NaOH and reacts that with metakaolin rather than forming an aqueous NaOH solution containing recycle mother liquor for the reaction with metakaolin.
Of course, it is evident that the present process does not require the exclusion of recycle mother liquor and washings from the reaction system and that under appropriate cm/
- 1074~
conditions such recycle may be advantageous. It is also evident that total recycle of the mother liquor is not usually desired in such systems since the purge of a portion of the recycle stream is usually desirable to avoid the build-up of impurities.
The present process utilizes the meta form of amorphous kaolin, called metakaolin, or the equivalent, prefer-ably produced by the calcination of kaolin at a temperature of from about 550 to about 900C. Such calcination is well known in the art and need not be discussed in greater detail here since it appears in U.S. Patent 3,114,603. As explained in U.S. Patent 3,114,603, it is usually desired to avoid prolonged time delay between the calcination of the feed kaolin and its use in the present process.
The following examples indicate preferred embodi-ments and aspects of the present invention.
250 grams H20 was added to a l-liter round bottom flask equipped with a heating mantla and an agitator at room temperature. 34.5 grams of NaOH beads was then added and the mixture was stirred until the NaOH was dissolved. 40 grams of metakaolin was added and the mixture was heated to 85C. The flask and contents was held at 85C for 2 hours while stirring.
The heating mantle was removed and the contents of the flask filtered with a Buchner funnel to recover the solid product. The product was washed with 500 grams of water and oven dried at 100C for 5 hours or more.
~ sample of the product was analyzed by X-ray diffraction and found to be 95 percent or higher zeolite A
(ASTM X-ray powder diffraction pattern File Card No. 11-590).
The mol ratios of the foregolng example are:
cm~ ' ' 10'74~
Na20/A1203 -= 2 .
SiO2/A1203 = 2 H20/A1203 = 78 H20/Na20 = 39 EXAMPLE I I :
Example I was repeated using 125 grams of water instead of 250 grams and a temperature of 80C instead of 85C.
Similar results were obtained. The H20/Na20 ratio was 20.
EXAMPLE I I I
153 gallons of deionized water was added to a steam jacketed, stirred, 250 gallon reactor. 184 pounds of sodium hydroxide beads was then added to the reactor. The mixture was heated to 179C and agitated until the beads dissolved.
Then 20~ pounds of metakaolin was added to the reactor and the temperature was increased to 185F (85C). This temperature was held 2-1/2 hours while the mixture was agitated. The reaction mass was cooled to approximately room temperature and discharged in four batches into a centrifuge for removal of the supernatant liquor. The centrifuge cake was washed with 262 gallons of deionized water. 286 lbs of zeolite A was recovered. The product was essentially 100 percent zeolite A as determined by X-ray diffraction.
Example I was repeated in a series of runs under various conditions. Results are tabulated with the results of Examples I and II included as Runs I and II, respectively.
cm/
1074~4 Q~ I
~ fi~ ~ I I I, ~
_ V . , , . ~
~ . ~ 0fi '. ~ o IIIooooo~oooo,~
tl~ N . h ~¢ fi ;~ U~ ~ ~ ~O ~ ~ ~ ~1 ~D' ~ ~ ~ ~
o ~ cr~ o ~ ~ t~ . "
. .
0 0 0 ~ ~ 0 0 0 . 0 0 0 ~1 .CU C~ NC'J 1~ N ~ ~t ~I C~ ~ N ~C) Ir~ O O U~ O O O ~ O
0 ~ CX~ ~
~0 ~0cd OOOOOOOOOOOOOO
~I h ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ .~
0~ o Lr~ o o o o o o o o o o o o N N N N 'CJ N N N N N N H
H H i~i P E;! p pH H X xH ~ X H ~
107~4 ~1~
_ V
~ o ~ o o h N
.
¢
rl C~l O O N O ~ J-. O If~ ,~
N
~ ~ fi ~J N ~ ~1 ~I C~l ~1 ~C~ O O U~ O O
~o O~ ~ CO ) ~ ct) c~, 0~1~
~0~ O O O O O O Oh ~ ~t ~ .
_ ~15 h ~ ~t ~ ~ ~t -0~ O O O O O O O
21 h ~ ~ O ~
H H H
I ~ ~ X X X X X
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing sodium zeolite A, which process comprises reacting metakaolin and sodium hydroxide in an aqueous system at a temperature of from about 80°C to about 85°C for from two to four hours, the metakaolin, water and sodium hydroxide being used in ratios that provide the desired Na, Al, Si and oxygen ratios of zeolite A product, the mol ratio of H2O/Na2O in the system being from about 15 to about 200.
2. The process of claim 1, wherein the sodium zeolite formed thereby has a purity of 90 percent or better.
3. The process of claim 1 wherein the temperature is about 85°C.
4. The process of claim 1 wherein the mol ratio of H2O/Na2O in the system is from about 25 to about 50.
5. The process of claim 1 wherein the mol ratio of H2O/Na2O in the system is about 40.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US69341276A | 1976-06-07 | 1976-06-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1074284A true CA1074284A (en) | 1980-03-25 |
Family
ID=24784538
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA277,129A Expired CA1074284A (en) | 1976-06-07 | 1977-04-27 | Chemical process |
Country Status (6)
Country | Link |
---|---|
JP (1) | JPS5316398A (en) |
BE (1) | BE855280A (en) |
CA (1) | CA1074284A (en) |
DE (1) | DE2725496B2 (en) |
FR (1) | FR2354287A1 (en) |
GB (1) | GB1551503A (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2418771A1 (en) * | 1978-03-02 | 1979-09-28 | Rhone Poulenc Ind | PROCESS FOR MANUFACTURING A SYNTHETIC SILICOALUMINATE AND PRODUCTS OBTAINED |
GB8517997D0 (en) * | 1985-07-17 | 1985-08-21 | English Clays Lovering Pochin | Synthesing faujasites |
DE3835760A1 (en) * | 1988-10-20 | 1990-04-26 | Bocklenberg & Motte Bomoro | MOTOR VEHICLE LOCK |
JP5594710B2 (en) * | 2008-03-19 | 2014-09-24 | 公益財団法人鉄道総合技術研究所 | Method for producing lithium-type zeolite |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1264441A (en) * | 1960-08-05 | 1961-06-19 | Grace W R & Co | Process for the preparation of synthetic crystalline zeolites |
FR1343946A (en) * | 1962-12-12 | 1963-11-22 | Grace W R & Co | Process for manufacturing microselective adsorbents and in particular sodium zeolites |
FR83942E (en) * | 1963-06-10 | 1964-11-06 | Grace W R & Co | Process for manufacturing micro-selective adsorbents and in particular sodium zeolites |
FR1387304A (en) * | 1963-12-20 | 1965-01-29 | Ministerul Ind Petrolului | Process for obtaining granules having different geometric shapes for molecular sieves with pores of 4 or 5 alpha, for the separation by fixed bed persorption of gas and liquid phases |
US3852105A (en) * | 1972-04-07 | 1974-12-03 | Rca Corp | Fabrication of dark heaters |
-
1977
- 1977-04-27 CA CA277,129A patent/CA1074284A/en not_active Expired
- 1977-06-01 FR FR7716708A patent/FR2354287A1/en not_active Withdrawn
- 1977-06-01 BE BE178099A patent/BE855280A/en unknown
- 1977-06-03 GB GB2376177A patent/GB1551503A/en not_active Expired
- 1977-06-06 DE DE19772725496 patent/DE2725496B2/en not_active Ceased
- 1977-06-06 JP JP6659777A patent/JPS5316398A/en active Pending
Also Published As
Publication number | Publication date |
---|---|
DE2725496B2 (en) | 1978-10-26 |
DE2725496A1 (en) | 1977-12-08 |
GB1551503A (en) | 1979-08-30 |
FR2354287A1 (en) | 1978-01-06 |
JPS5316398A (en) | 1978-02-15 |
BE855280A (en) | 1977-12-01 |
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Legal Events
Date | Code | Title | Description |
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MKEX | Expiry |