GB2051024A - Process for preparing crystalline sodium silico-aluminate of zeolite A type - Google Patents
Process for preparing crystalline sodium silico-aluminate of zeolite A type Download PDFInfo
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- GB2051024A GB2051024A GB8012730A GB8012730A GB2051024A GB 2051024 A GB2051024 A GB 2051024A GB 8012730 A GB8012730 A GB 8012730A GB 8012730 A GB8012730 A GB 8012730A GB 2051024 A GB2051024 A GB 2051024A
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- Prior art keywords
- zeolite
- suspension
- process according
- solution
- particles
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- 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)
- C01B33/2823—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) from aqueous solutions of an alkali metal aluminate and an alkali metal silicate excluding any other source of alumina or silica
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/33—Wastewater or sewage treatment systems using renewable energies using wind energy
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- 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)
- Detergent Compositions (AREA)
Abstract
Process for the semi-continuous preparation of a zeolite A type silicoaluminate of constant and homogeneous quality, which process comprises continuously mixing, with vigorous agitation, a solution of sodium aluminate and a solution of sodium silicate in a container in which the average retention time is from 30 seconds to 20 minutes and the temperature is from 70 to 105 DEG C to form a gel which is subsequently matured over a period of 4 to 7 hours at a temperature of from 80 to 95 DEG C, and wherein during maturing precipitated particles of zeolite are kept in suspension without any shearing force being exerted thereon, or with just enough shearing force to ensure that the particles are kept in suspension. Zeolite A having 95% of crystals with diameter 1-8 pi average diameter 2-4 pi and sequestering power of 120 mgCa/g is claimed.
Description
SPECIFICATION
Process for preparing crystalline sodium silicoaluminate of zeolite A type
The present invention relates to the industrial preparation of crystallised sodium silicoaluminate of the zeolite A type, having a high ion-exchange capacity in relation to calcium ions and consisting of particles having an average diameter of from 2 to 4Ci, 95% of the particles having a diameter within a range from 1 to 8 .
The main applications of zeolites are based on their well known cation-exchanging properties, which are described for example in the "Comprehensive Treatise on Inorganic and Theoretical
Chemistry" by J. W. MELLOR, vol. VI, part 2, Longman Editors 1925, pp. 575-579. Zeolites are particularly useful for the sequestration of calcium ions.
To enables zeolites to be used as a substitute for phosphates in washing and rinsing agents, they must have the highest possible ion-exchange capacity, whilst remaining in suspension in the aqueous solutions so as to prevent undesirable deposits on laundry after washing and rinsing. This is why it is essential that the particle size be as small as possible, preferably around an average diameter of 2 to 3 .
The conditions of synthesis of zeolite A (of general formula Na2O. Al203.2SiO2. xH2O, wherein x varies from 1 to 8 but is generally equal to 4 or 5) have been known for a number of years, particularly from "lon-Exchange" by Friedrich HELFFERICH, 1962, McGraw-Hill Book Company, chap. 2, pp. 10-16. The conditions influencing the particle size distribution of the zeolite formed have also been studied, for example, in "Kinetic studies on the formation of zeolite A" by W. MEISE and F. E. SCHWOCHOW in "Molecular Sieves" 121 (1973) pp. 169-178.
Numerous patents describe the conditions of preparation which cause variations in the quality of the raw materials, the reaction temperature, the method of addition of the reagents, etc.
German Patent Application No.25 17218 describes, in particular, the use of shearing forces in the course of the crystallisation stage, and the optional maturing stage which follows, in order to obtain zeolite A having an average particle size of up to 6.5,a, but with an unspecified sequestering power.
In our French Patent Application 78/35344, we have described a process for the semi-continuous preparation of zeolite A, which comprises carrying out instantaneous and continuous mixing of solutions of sodium aluminate and sodium silicate in a container in which the average retention time is from 30 seconds to 20 minutes, to form a gel which is subsequently crystallised discontinuously. This process yields a zeolite A the sequestering power of which is from 110 to 120 mg Ca++/g of anhydrous product, and which has particles of sizes from 2.9 to 6Su, the particle size distribution curve indicating that 90% of the particles have a diameter of less than 11,u.
We have now perfected a process for obtaining a zeolite A which has a sequestering power of more than 120 mg Ca++/g of anhydrous product, and which has a particularly fine and restricted particle size, the average diameter of the particles being from 2 to 4,a. This product therefore proves particularly valuable as a sequestering agent for Ca++ ions for use in washing powders.
According to the present invention there is provided a process for the semi-continuous preparation of a zeolite Atype silicoaluminate of constant and homogeneous quality, which process comprises continuously mixing, with vigorous agitation, a solution of sodium aluminate and a solution of sodium silicate in a container in which the average retention time is from 30 seconds to 20 minutes and the temperature is from 70 to 105"C, to form a gel which is subsequently matured over a period of 4 to 7 hours at a temperature of from 80 to 95"C, and wherein during maturing precipitated particles of zeolite are kept in suspension without any shearing force being exerted thereon, or with just enough shearing force to ensure that the particles are kept in suspension.
Mixing of the solutions of sodium aluminate and sodium silicate is carried out at a temperature of from 70 to 105"C with the maximum possible stirring, in order to obtain a perfectly homogeneous gel.
This gel stays in the reactor for an average period of time sufficient to ensure complete formation of the gel, i.e. from 30 seconds to 20 minutes.
The addition of the two reaction solutions, the flow rates of which are regulated, preferably takes place in the high suction zone created by a turbine the rotation speed of which must be greater than 2,500 r.p.m. The mixing and sheering action of this turbine is further increased if it is placed in a fixed saucer which rotates at the same time as the turbine.
The sodium silicoaluminate gel thus continuously prepared is transferred, by overflowing, into a second reactor comprising a system which enables the product obtained to be kept in suspension and maintained art a constant temperature of from 80 to 95"C to permit crystallisation of the zeolite A. This crystallisation thus occurs discontinuously, the retention time in the crystallisation tank being from 1 to 15 hours, preferably from 4to 7 hours.
When the zeolite is put into and kept in suspension by means of a stirrer, this stirrer rotates at a speed such that the tangential speeds are from 0.2 to 5 m/s.
The process can also be effected by the use of ultrasonic waves, convection currents caused by local heating, or by the use of a jig, which is a mechanical concentrator which effects separation of heavy grains from light grains by relying on the different abilities of the different grains to penetrate a semistationary bed. Such jigs are described, for example, in Handbook of Mineral Dressing, by
Arthur F. Taggart, J. Wiley & Sons Inc, Section 11,
Page 4.
The discontinuous crystallisation carried out under these conditions means that the particle size of the end product can be controlled at will, and at the same time particularly high sequestering powers are obtained. This result is obtained by adjustment, in coordinated manner, of the following parameters: temperature, retention time, speed of agitation and concentration of the reagents.
The continuous preparation of the gel gives the desired properties when the sodium aluminate solutions are characterised by a weight ratio of Awl203
Na2O of from 0.5 to 1.5, with an aqueous concentration of
Na2O of from 30 to 200 g/l, and when the sodium silicate solutions are characterised by a weight ratio of
SiO2 Na2O of from 1.5 to 3.5, with an aqueous concentration of
Na2O of from 20 to 120 g/l.
The sodium aluminate solutions are preferably obtained either by reacting hydrated alumina with a sodium hydroxide solution, or by taking them from a
Bayer cycle forthe production of alumina. The sodium silicate solutions are preferably prepared from raw silica and soda materials which can vary according to the economic criteria involved, e.g.
powdered industrial sodium silicate, industrial sodium silicate solutions, silica contained in sand and soda, soda and silica gel recovered from the fluorosilicicacid residue from a plant for the production of aluminium fluoride or hydrofluoric acid, or from the treatment of the gases released in the processing of natural phosphates, or sodium silicate obtained from a plant for the desilication of bauxites before processing in alumina-producing factories, or residual silica obtained in the production of aluminium salts by wet reaction of natural silicoaluminates such as kaolin or clays, or silica obtained thermally, e.g. in the production of magnesium, silicon metal or silicon alloys.
The mixture obtained by adding these solutions of
Na aluminate and silicate together should have a weight ratio of Awl203 SiO2 of from 0.5 to 1.2 and the Na2O content should be adjusted so that the soda concentration of the liquor in which this crystallisation is carried out after precipitation is not more than 135 g/l of NaOH, to prevent crystallisation of the inactive silicoaluminates ofthe feldspar type, but is not less than 26 g/l of NaOH, to ensure that the rate of crystallisation of the zeolite A is compatible with industrial production.
After a maturing period for the crystals of from 1 to
15 hours, preferably 4to 7 hours, a suspension of zeolite A in the liquor as described above is obtained. This suspension is then subjected to suitable solid/liquid separation (for example, filtering, decanting or centrifuging).
The solid thus separated is washed with water and then dried. The washing water is recovered and
mixed with the liquor separated from the solid. All this residual water is recycled in order to prepare the sodium atuminate solutions required for the production process.
Drying may cause agglomeration of the crystals.
Since this is prejudicial to satisfactorily keeping the
zeolite A in suspension in the detergent solution, it is then necessary to carry out selection or separation of the particles or both operations combined, by any suitable method.
The zeolite A produced by the process described above has the following characteristics:
- narrow particle size distribution, 95% of the particles having a diameter within the range from 1 to 8E.L.
- a very fine and very restricted average particle size of from 2 to 4,a which can be adjusted depending on the intended use.
- a calcium ion-exchanging capacity of more than 120 mg Ca++ per gram ofanhydrous product.
-a pH offrom 10to 11 forthezeoliteAin a 1% aqueous suspension.
This zeolite A is particularly suitable for use in washing powders for softening hard water.
The following Examples illustrate the invention.
EXAMPLE 1
A sodium silicoaluminate of the zeolite A type is prepared by continuously mixing a sodium silicate solution A with a sodium aluminate solution B in a reactor which permits instantaneous mixing of the two solutions. The gel obtained is subjected to discontinuous maturing in a maturing vessel.
The sodium silicate solution A is obtained by dissolving crystalline commercial grade sodium silicate in demineralised water at 50"C. It has the following characteristics:
SiO2concentration 138 g/l Na2O concentration 41 gIl temperature = 50"C at the moment of use
The sodium aluminate solution B is obtained by dissolving hydrated alumina in concentrated soda at 104"C so as to obtain: AI2O3 concentration 56 g/l Na2O concentration 80 gll temperature = 92"C at the moment of use
The solutions A and B are simultaneously passed into a reactor fitted with a turbine rotating at 8000 rpm.The solutions A and B have flow rates such that the retention time in the reactor is 2 minutes, whilst the weight ratio of Al2OSiO2 is 1.4.
The gel thus obtained is transferred, by decanting, into the maturing vessel. The sodium silicoaluminate is kept in suspension at 80 C by using a bladetype agitator rotating at 20 rpm.
After 15 hours maturing, the zeolite is separated off by filtration and then washed and dried until a
product containing 20 to 22% of hydration water is obtained.
The zeolite thus obtained has the following properties:
(a) An X-ray diffraction diagram indicating that
more than 87% of the product is crystallised zeolite
A.
(b) A particle size characterised by:
an average diameter of the particles of 3.9,u 97% of the particles having a diameter less than 8,a 1% of the particles having a diameter less than 1 CL (The particle size is measured by means of an
X-ray sedimentometer).
(c) A sequestering power of 121 mg of Ca per
gram of anhydrous product. This property is meas
ured by reacting a known quantity of zeolite with an aqueous solution containing 200 mg of calcium per litre (50" of hardness and a pH of 10), with vigorous stirring for 15 minutes at 22"C. Some of the calcium ions are fixed by the zeolite. After filtration and rinsing of the latter, the calcium remaining in solution is measured in this filtrate by potentiometric titration using a calibrated solution of ethylene diamine tetra-acetic acid.
EXAMPLE2
The following solutions are prepared by the method given in Example 1:
Solution A:
SiO2 concentration 119 g/l Na2O concentration 36 gll temperature = 90" at the moment of use
Solution B:
Al203 concentration 97 gll Na2O concentration 99 g/l temperature = 90" at the moment of use.
Solutions A and B are simultaneously passed into the high suction zone of a turbine placed in a reactor.
This turbine rotating at 300 r.p.m. is placed in a saucer rotating on itself. This saucer consists of two plates the concave portion of which is directed towards the turbine. These two plates define a space into which the two reaction solutions are injected.
Solutions A and B have flow rates such that the retention time in the reactor is 12 mins, whilst the ratio of Al203 to SiO2 is 1.35.
The gel thus obtained is transferred by overflow into a maturing tank. The sodium silicoaluminate is kept in suspension at900C by using a blade-type agitator rotating at 20 r.p.m.
After 5 hours maturing, the zeolite is separated by the same methods as in example 1.
The zeolite thus obtained has the following properties :
(a) more than 93% of the product is crystalline zeolite A.
(b) particle size characterised by:
average particle diameter 3.0y 99% of the particles have a
diameter less than
all the particles have diameter
largerthan
(c) sequestering power (determined as in Example 1) = 129 mg of Ca per g of anhydrous product.
EXAMPLE 3
Sodium silicoaluminate is prepared from the solutions and according to the method described in
Example 2, the only difference being the speed of agitation in the maturing tank, which is maintained at 140 r.p.m. for 5 hours.
At the end of this period, the zeolite is separated by the same methods as in Example 1.
The zeolite thus obtained has the following properties:
(a) more than 91% of the product is crystalline zeolite A
(b) particle size characterised by:
average particle diameter 5.2,u 93% of the particles have a diameter
less than
no particle with a diameter
less than
(c) sequestering power (determined by the method of Example 1)
= 106 mg Ca/g of anhydrous product.
This example shows that too much agitation yields poor results.
EXAMPLE 4
A zeolite is prepared with the solutions and using the method described in Example 2, the only difference being the method of agitation in the maturing tank. Agitation is effected by subjecting the liquid to ultrasonic waves.
After 5 hours, the zeolite is separated by the same methods as in Example 1.
The zeolite thus obtained has the following properties:
(a) more than 92% of the product is crystalline zeolite A
(b) particle size characterised by:
average particle diameter 2.4y all the particles have a
diameter less than
4% of particles have a
diameter less than
(c) sequestering power (determined by the method described in Example 1) = 130 mg Ca/g of anhydrous product.
EXAMPLE 5
A zeolite is prepared using the solutions and method described in Example 2, the only difference being the method of agitation in the maturing tank.
This is effected by convection, by subjecting the liquid to very localised heating atthe bottom of the tank, the excess calories supplied being evacuated by a cold water coil located at the top of the tank.
The average temperature in the suspension is maintained at 90"C by regulating the cooling water.
After 5 hours maturing, the zeolite is separated by the same method as in Example 1.
The zeolite thus obtained has the following properties:
(a) more than 94% of the product is crystalline zeolite A
(b) particle size characterised by average
particle diameter 3.2cm 98% of particles have a diametersmallerthan 8,a all the particles have
a diameter largerthan (c) sequestering power (determined by the method in Example 1) = 125 mg Ca/g of anhydrous product.
Claims (12)
1. Process for the semi-continuous preparation of a zeolite A-type silicoaluminate of constant and homogeneous quality, which process comprises continuously mixing, with vigorous agitation, a solution of sodium aluminate and a solution of sodium silicate in a container in which the average retention time is from 30 seconds to 20 minutes and the temperature is from 70 to 105"C, to form a gel which is subsequently matured over a period of 4to 7 hours at a temperature of from 80 to 95"C, and wherein during maturing precipitated particles of zeolite are kept in suspension without any shearing force being exerted thereon, or with just enough shearing force to ensure the particles are kept in suspension.
2. Process according to Claim 1, wherein the suspension of precipitated particles is maintained by the use of ultrasonic waves.
3. Process according to Claim 1, wherein the suspension of precipitated particles is maintained by the use of impellers of the marine screw type or helical impellers with a low shearing level.
4. Process according to Claim 1, wherein the suspension of precipitated particles is maintained by the use of a jig (as hereinbefore defined).
5. Process according to Claim 1, wherein the suspension of precipitated particles is maintained by the use of rollers of the concrete-mixing type.
6. Process according to Claim 1, wherein the suspension is maintained by using localised heating to create convection currents in the solution.
7. A process according to any one of the preceding claims, wherein the solution of sodium aluminate has a weight ratio of Al2ONa2O of from 0.5 to 1.5 with an aqueous concentration of Na2O of from 30 to 200 g/l.
8. A process according to any one of the preceding claims, wherein the solution of sodium silicate has a weight ratio of SiO2/Na2O of from 1.5 to 3.5, with an aqueous concentration of Na2O of from 20 to 120 gull.
9. A process according to Claim 1 substantially as hereinbefore described in the Examples.
10. AzeoliteAtype silicoaluminatewhen pre
pared by a process as claimed in any one of the
preceding claims.
11. Silicoaluminate of the zeolite Atype wherein
95% of the crystals have a diameter within a range
from 1 to 8,zz, the average diameter being from 2 to 4jL, and having a sequestering power of more than
120 mg of calcium per gram of anhydrous product.
12. A washing powder incorporating a zeolite A
type silicoaluminate as claimed in Claim 10 or 11.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7910323A FR2454997A1 (en) | 1979-04-24 | 1979-04-24 | ZEOLITE CRYSTALLIZATION DURING INDUSTRIAL MANUFACTURING PROCESSES |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2051024A true GB2051024A (en) | 1981-01-14 |
| GB2051024B GB2051024B (en) | 1983-01-12 |
Family
ID=9224653
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8012730A Expired GB2051024B (en) | 1979-04-24 | 1980-04-17 | Process for preparing crystalline sodium silicoaluminate of zeolite a type |
Country Status (31)
| Country | Link |
|---|---|
| JP (1) | JPS569213A (en) |
| AR (1) | AR223215A1 (en) |
| AU (1) | AU532923B2 (en) |
| BE (1) | BE882821A (en) |
| BR (1) | BR8002468A (en) |
| CA (1) | CA1150711A (en) |
| CH (1) | CH646400A5 (en) |
| DD (1) | DD150738A5 (en) |
| DE (1) | DE3015415C2 (en) |
| DK (1) | DK173180A (en) |
| EG (1) | EG14269A (en) |
| ES (1) | ES8200627A1 (en) |
| FI (1) | FI67792C (en) |
| FR (1) | FR2454997A1 (en) |
| GB (1) | GB2051024B (en) |
| GR (1) | GR67291B (en) |
| HU (1) | HU183168B (en) |
| IN (1) | IN154062B (en) |
| IT (1) | IT1129078B (en) |
| LU (1) | LU82383A1 (en) |
| MA (1) | MA18823A1 (en) |
| NO (1) | NO801181L (en) |
| OA (1) | OA06574A (en) |
| PH (1) | PH16460A (en) |
| PL (1) | PL223685A1 (en) |
| PT (1) | PT71133A (en) |
| RO (1) | RO79835B (en) |
| SE (1) | SE8003020L (en) |
| TR (1) | TR21137A (en) |
| YU (1) | YU112680A (en) |
| ZA (1) | ZA802441B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4661333A (en) * | 1982-06-21 | 1987-04-28 | Internationale Octrooi Maatschappij "Octropa" Bv | Aluminosilicates |
| US5474753A (en) * | 1990-11-09 | 1995-12-12 | Laviosa Rhone-Poulenc | Preparation of crystalline 4A zeolites |
| WO2010128342A1 (en) | 2009-05-06 | 2010-11-11 | Barchem Llc | Zeolite 4a with new morphological properties, its synthesis and use |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DD292432A5 (en) * | 1989-04-10 | 1991-08-01 | ������@������������k�� | METHOD FOR PRODUCING A FINE-PARTICULAR TYPE 4A CRYSTALLINE ZEOLITE POWDER WITH PREDETERMINABLE GRAIN SIZE DISTRIBUTION |
| FR3076828A1 (en) * | 2018-01-15 | 2019-07-19 | Arkema France | PROCESS FOR THE PREPARATION OF CONTINUOUS ZEOLITES BY MEANS OF ULTRASOUND |
| DE102018107430A1 (en) * | 2018-03-28 | 2019-10-02 | Dimos Maschinenbau Gmbh | transport vehicle |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1280877A (en) * | 1961-01-14 | 1962-01-08 | Socony Mobil Oil Co | Process for preparing crystalline zeolites |
| GB1115489A (en) * | 1964-07-31 | 1968-05-29 | Deputy Minister | A process to manufacture crystalline synthetic zeolites for use as molecular sieves |
| US3425800A (en) * | 1967-10-05 | 1969-02-04 | Aluminum Co Of America | Production of crystalline zeolites |
| AT322511B (en) * | 1970-06-15 | 1975-05-26 | Martinswerk G M B H Fuer Chem | PROCESS FOR THE DIRECT MANUFACTURING OF A PURE CRYSTALLINE ZEOLITHIC MOLECULAR SCREEN WITH A PORE WIDTH OF 4Å. |
| DE2651485A1 (en) * | 1976-11-11 | 1978-05-24 | Degussa | TYPE A I CRYSTALLINE ZEOLITE POWDER |
| FR2398698A1 (en) * | 1977-07-29 | 1979-02-23 | Ugine Kuhlmann | ZEOLITHE A CONTINUOUS INDUSTRIAL MANUFACTURING PROCESS |
| US4150100A (en) * | 1978-06-13 | 1979-04-17 | Pq Corporation | Preparing zeolite NaA |
-
1979
- 1979-04-24 FR FR7910323A patent/FR2454997A1/en active Granted
-
1980
- 1980-04-02 IN IN237/DEL/80A patent/IN154062B/en unknown
- 1980-04-08 AR AR28058880A patent/AR223215A1/en active
- 1980-04-13 EG EG22580A patent/EG14269A/en active
- 1980-04-15 GR GR61695A patent/GR67291B/el unknown
- 1980-04-17 GB GB8012730A patent/GB2051024B/en not_active Expired
- 1980-04-17 PH PH25915A patent/PH16460A/en unknown
- 1980-04-17 BE BE0/200254A patent/BE882821A/en not_active IP Right Cessation
- 1980-04-18 TR TR2113780A patent/TR21137A/en unknown
- 1980-04-21 MA MA19018A patent/MA18823A1/en unknown
- 1980-04-22 DE DE3015415A patent/DE3015415C2/en not_active Expired
- 1980-04-22 LU LU82383A patent/LU82383A1/en unknown
- 1980-04-22 DD DD80220621A patent/DD150738A5/en unknown
- 1980-04-22 CH CH310480A patent/CH646400A5/en not_active IP Right Cessation
- 1980-04-22 SE SE8003020A patent/SE8003020L/en not_active Application Discontinuation
- 1980-04-23 BR BR8002468A patent/BR8002468A/en unknown
- 1980-04-23 ZA ZA00802441A patent/ZA802441B/en unknown
- 1980-04-23 AU AU57723/80A patent/AU532923B2/en not_active Ceased
- 1980-04-23 PT PT7113380A patent/PT71133A/en unknown
- 1980-04-23 NO NO801181A patent/NO801181L/en unknown
- 1980-04-23 HU HU801002A patent/HU183168B/en unknown
- 1980-04-23 ES ES490827A patent/ES8200627A1/en not_active Expired
- 1980-04-23 DK DK173180A patent/DK173180A/en active IP Right Grant
- 1980-04-23 PL PL22368580A patent/PL223685A1/xx unknown
- 1980-04-23 CA CA000350514A patent/CA1150711A/en not_active Expired
- 1980-04-23 IT IT6764680A patent/IT1129078B/en active
- 1980-04-24 JP JP5367480A patent/JPS569213A/en active Pending
- 1980-04-24 FI FI801322A patent/FI67792C/en not_active IP Right Cessation
- 1980-04-24 YU YU112680A patent/YU112680A/en unknown
- 1980-04-24 RO RO100943A patent/RO79835B/en unknown
- 1980-04-24 OA OA57093A patent/OA06574A/en unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4661333A (en) * | 1982-06-21 | 1987-04-28 | Internationale Octrooi Maatschappij "Octropa" Bv | Aluminosilicates |
| US5474753A (en) * | 1990-11-09 | 1995-12-12 | Laviosa Rhone-Poulenc | Preparation of crystalline 4A zeolites |
| WO2010128342A1 (en) | 2009-05-06 | 2010-11-11 | Barchem Llc | Zeolite 4a with new morphological properties, its synthesis and use |
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