AU768253B2 - Process for preparing artificial zeolite by a slurry reaction method - Google Patents
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- AU768253B2 AU768253B2 AU44700/99A AU4470099A AU768253B2 AU 768253 B2 AU768253 B2 AU 768253B2 AU 44700/99 A AU44700/99 A AU 44700/99A AU 4470099 A AU4470099 A AU 4470099A AU 768253 B2 AU768253 B2 AU 768253B2
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- Prior art keywords
- reaction
- zeolite
- slurry
- concentration
- alkali
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- 238000006243 chemical reaction Methods 0.000 title claims description 55
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 title claims description 33
- 239000010457 zeolite Substances 0.000 title claims description 29
- 229910021536 Zeolite Inorganic materials 0.000 title claims description 28
- 239000002002 slurry Substances 0.000 title claims description 18
- 238000000034 method Methods 0.000 title claims description 14
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000007864 aqueous solution Substances 0.000 claims description 18
- 239000010881 fly ash Substances 0.000 claims description 15
- 239000003513 alkali Substances 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 9
- 239000011541 reaction mixture Substances 0.000 claims description 9
- 239000002956 ash Substances 0.000 claims description 8
- 238000000926 separation method Methods 0.000 claims description 7
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims description 6
- 230000007423 decrease Effects 0.000 claims description 6
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- 238000001704 evaporation Methods 0.000 claims description 5
- 235000019353 potassium silicate Nutrition 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 5
- 230000008020 evaporation Effects 0.000 claims description 4
- 239000010802 sludge Substances 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 239000003245 coal Substances 0.000 claims description 2
- 238000002485 combustion reaction Methods 0.000 claims 1
- 238000007086 side reaction Methods 0.000 claims 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 63
- 239000000243 solution Substances 0.000 description 10
- 238000007796 conventional method Methods 0.000 description 8
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 230000035484 reaction time Effects 0.000 description 5
- 238000013019 agitation Methods 0.000 description 4
- 229910000323 aluminium silicate Inorganic materials 0.000 description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 239000001110 calcium chloride Substances 0.000 description 2
- 229910001628 calcium chloride Inorganic materials 0.000 description 2
- 238000010924 continuous production Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical group [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- JYIBXUUINYLWLR-UHFFFAOYSA-N aluminum;calcium;potassium;silicon;sodium;trihydrate Chemical compound O.O.O.[Na].[Al].[Si].[K].[Ca] JYIBXUUINYLWLR-UHFFFAOYSA-N 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 229910001603 clinoptilolite Inorganic materials 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000002781 deodorant agent Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- YGANSGVIUGARFR-UHFFFAOYSA-N dipotassium dioxosilane oxo(oxoalumanyloxy)alumane oxygen(2-) Chemical compound [O--].[K+].[K+].O=[Si]=O.O=[Al]O[Al]=O YGANSGVIUGARFR-UHFFFAOYSA-N 0.000 description 1
- 239000010433 feldspar Substances 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 229910052680 mordenite Inorganic materials 0.000 description 1
- 229910052627 muscovite Inorganic materials 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000004846 x-ray emission Methods 0.000 description 1
Landscapes
- Silicates, Zeolites, And Molecular Sieves (AREA)
- Processing Of Solid Wastes (AREA)
Description
P/00/0011 Regulation 3.2
AUSTRALIA
Patents Act 1990 COMPLETE
SPECIFICATION
FOR A STANDARD
PATENT
ORIGINAL r Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: K.E.M. CORPORATION Yukuo KATAYAMA CARTER SMITH BEADLE 2 Railway Parade Camberwell Victoria 3124 Australia PROCESS FOR PREPARING ARTIFICIAL
ZEOLITE
BY A SLURRY REACTION
METHOD
The following statement is a full description of this invention, including the best method of performing it known to us PROCESS FOR PREPARING ARTIFICIAL ZEOLITE BY A SLURRY REACTION
METHOD
FEILD OF THE INVENTION The invention relates to a process for the preparation of zeolite from incineration ash such as flyash and other aluminosilicate-containing substances.
DESCRIPTION OF THE PRIOR ART As zeolite, which is crystalline aluminosilicate, naturally occurring zeolites are known, such as mordenite and clinoptilolite. Synthetic zeolites such as A zeolite and Y zeolite prepared from sodium silicate and sodium aluminate are used as a catalyst, molecular sieve and the like.
Meanwhile, it is also known to prepare zeolite by heating a slurry of flyash and an aqueous solution of alkali at a several tens to 1000 for several hours. This zeolite is generally 00* called artificial zeolite. The artificial zeolite has similar S 20 ion exchange ability and adsorption ability as natural zeolite and synthetic zeolite do. However, its composition, crystalline structure, and purity are not precisely controlled, compared to those of synthetic zeolite. Meanwhile, the artificial zeolite is cheaper and suitable to mass consumption applications, for example, a soil improvement material and a deodorant. However, it should be much cheaper for broader applications and thus an improvement on the process for its preparation is required.
In a conventional method where a mixture of 2.2 liters of an aqueous solution of alkali per kg of flyash is heated to 100C, it takes 5 hours (Japanese Patent Application Laid-Open 6-321525). The present inventor found that it takes 20 hours to achieve a conversion of Moreover, the reaction mixture obtained after the reaction contains a lot of by-produced water glass besides zeolite, and, consequently, the reaction mixture is sticky, which requires a high cost for solid (zeolite)-liquid separation. Further, the separated zeolite is still sticky and requires a lot of water and time to wash with water.
PURPOSE OF THE INVENTION The present invention provides a process for preparing high quality artificial zeolite, preferably, at a conversion to zeolite above 50% in a short reaction time, where solid-liquid separation is made easier or unnecessary by reducing the amount of by-produced water glass (soluble silicate), and wasteful consumption of sodium hydroxide, potassium hydroxide and the S 20 like is decreased.
SUMMARY OF THE INVENTION Conventionally, a concentration of alkali in an aqueous phase of a reaction system decreases with the progress of the reaction. The present inventor has now found that when the decrease in the concentration of alkali is at least suppressed or, preferably, avoided by evaporating water to remove from the reaction system during the reaction, the by-production of water glass is suppressed to make the reaction mixture non-sticky and, therefore, solid-liquid separation is easier or most of the water in the reaction system can be evaporated by the end of the reaction. In any case, there is no difficulty inherent to the conventional method in removing liquid from the reaction mixture. Further, the supplied alkali is used more effectively for the reaction.
Further, although it has been considered that even if the reaction temperature is raised above 1001C, there are not attained sufficient advantages, an increase in crystallinity to counterbalance the cost(Japanese Patent Application Laid-Open 6-321525, paragraph 0041), the present inventor has now found that in the process according to the present invention, a higher conversion can be achieved in a shorter time by applying a reaction temperature above 100°C and the amount of alkali metal hydroxide such as sodium hydroxide is smaller, and therefore the amount of water to be used is smaller, which is advantageous in heat efficiency.
The present invention is a process for preparing artificial zeolite comprising the steps of mixing x kilograms of incineration ash or any other aluminosilicate-containing substance with y liters of an aqueous solution of alkali metal hydroxide having a concentration of 1 N or higher in a proportion, y/x, of 0.1 to 1.5 (liter/kg) to prepare a slurry; and heating the slurry to cause a zeolite-forming reaction wherein water is continuously or intermittently removed by evaporation so that a. decrease in a concentration of alkali.
which would otherwise naturally occur with a progress of the reaction is at least suppressed to thereby facilitate the reaction.
Also the present invention includes the process, wherein the heating takes place at a temperature of higher than 100C and at most 350°C.
BRIEF DESCRIPTION OF THE DRAWINGS Fig.l is a graph a relation between a reaction time and a conversion.
Fig.2 is a graph showing a relation between a concentration of alkali and a conversion.
Fig.3 is a graph showing a relation between a reaction temperature and a reaction time.
Fig.4 is a flow diagram of a continuous production system according to the present invention.
DESCRIPTION OF THE PREFERRED
EMCODIMENTS
The present invention will be explained by reference to Fig.l, but not is restricted by it.
Fig.l shows the results of experiments made by using a pressurized agitation autoclave. Flyash and an aqueous Normal(N) sodium hydroxide solution were fed in a proportion of 2kg/l liter and heated to 150°C. The abscissa indicates a reaction time and the ordinate indicates a conversion to zeolite.
The conversion was measured by X-ray fluorescence spectroscopy.
According to the present invention, at a time of 45 minutes after start of the heating, an aliquot of water corresponding to 10 wt.% of the fed flyash was removed by evaporation from a valve at an upper part of the autoclave (curve A) The conversion before the water removal was around 15% and its increase was extremely small. However, the conversion increased suddenly after the water removal. The conversion exceeded at a time of 1.5 hours, but its increase tended to become small.
Water was continuously removed from that time to a time of 2 hours. Then, the conversion increased suddenly again to reaclh 57%.
If the water removal according to the present invention is not carried out, the conversion stays at about 20% even at a time of 2 hours. To attain a higher conversion by a conventional method, an amount of sodium hydroxide to be fed may be made larger o°•e oo to reduce a decrease in a concentration of sodium hydroxide.
Generally, use of an aqueous solution of sodium hydroxide having a concentration of 4N or larger is avoided in fear of corrosion of apparatus, and consequently the feed amount of the aqueous solution of sodium hydroxide is inevitably increased. Curve ~B in Fig. 1 shows an extreme example of that case. That is, when as large as 10 liters of an aqueous 3.5N sodium hydroxide solution per kg of flyash is used, which amount is 20 times the amount used in Curve A, a conversion as high as more than can be attained in 1.5 hours. However, this results not onl., in a low production amount per volume of a reactor, but also in high costs for heating and after-treatment of the large amount of the aqueous solution, which is not practical. In Japanese Patent Application Laid-Open 6-321525, 2.2 liters of an aqueous 2N sodium hydroxide solution is used per kg of flyash, while in the present invention, the amount of an aqueous sodium hydroxide solution is so small as 1.5 liters or less, and still 6 an extremely high conversion is achieved which can not be attained by the conventional method.
A reaction mixture produced in the method of the present invention is preferably not in a slurry state but in a solid.
state. The reaction mixture obtained in the conventional method is sticky due to a by-produced water glass (soluble silicate) and contains a lot of water. Accordingly, it is difficult to separate the liquid. The invention described in Japanese Patent Application Laid-Open 6-321525 is to solve this problem by separating and purifying an excess amount of an oooo aqueous solution of alkali and a product crystals with a liquid o0.. separation apparatus after lowering the temperature of the slurry to 700C or lower. In the present invention, a liquid separation process is preferably no longer used.
The obtained reaction mixture is preferably subjected to a washing process to remove the residual alkali metal hydroxide.
There are no difficulties in washing and liquid separation unlike in the conventional methods. For washing, an aqueous solution of calcium chloride or a diluted hydrochloric acid solution is preferred.
The incineration ash as a raw material includes residues after incinerating coal, active sludge, paper sludge, garbage and the like, among which flyash is preferred. The aluminosilicate-containing substances other than the incineration ash include naturally occurring minerals such as analcite, muscovite, feldspar, and volcanic ash.
The concentration of the aqueous solution of alkali hydroxide is 1N or higher, preferably 2 to 4N. If the concentration is lower than the lower limit, a reaction rate is too small to achieve a high conversion in a short time. Data supporting this are shown in Fig.2. A so large amount as liters of an aqueous solution of sodium hydroxide with a predetermined concentration per kg of flyash was fed to a pressurized agitation autoclave. Then, a decrease in the concentration of the sodium hydroxide with the progress of the reaction was small, and relation between the concentration and the conversion could be seen. The reaction was carried out at 150C for 2 hours. The ordinate indicates the predetermined concentration, and the abscissa indicates the attained conversion. For a conversion of 30%, a concentration of 2N is required; and for a conversion of 50%, a concentration of 3N is required. Therefore, it can be seen that, when a smaller amount of an aqueous solution of sodium hydroxide is used according to the present invention, ahigh conversion to zeolite can be attained by maintaining the concentration of sodium 20 hydroxide at this level by removing water according to the present invention after the sodium hydroxide is consumed with the progress of the reaction.
As to alkali metal hydroxide, sodium hydroxide or potassium hydroxide is preferably used.
Zero point one to one point five liters, preferably 0.2 to 0.7 liters of the aqueous solution of sodium hydroxide is mixed with each 1 kg of incineration ash or aluminosilicatecontaining substance (hereinafter represented by flyash as a 8 typical example). Usually, the amount of an aqueous sodium hydroxide solution is smaller when a concentration of the solution is higher; and it is larger when the concentration is lower.
Conventionally, the reaction took place at 100C or lower.
However, a time needed to achieve a predetermined conversion.
becomes significantly shorter by setting the reaction temperature above 100°C. Fig. 3 shows data from experiments where 10 liters of an aqueous 3.5N sodium hydroxide solution per kg of flyash was fed in a pressurized agitation autoclave, and heated at a predetermined temperature to determine a reaction time necessary to obtain a predetermined conversion Although the large amount of an aqueous solution of sodium hydroxide was used, it took 20 hours to achieve a so high conversion as 50%at 100°C according to the conventional method. However, 6 hours and 1.7 hours are enough at 125°C and 150°C, respectively. In these experiments, to make data easier to be understood, a large amount of an aqueous solution of sodium 20 hydroxide is used and no water was removed. The same tendency is observed when the amount of the aqueous solution of sodium hydroxide is decreased and water removal is carried out. In the conventional method where a large amount of aqueous solution is used, if the reaction is carried out at a high temperature, a large amount of heat is needed, which is uneconomical. This is avoided in the present method. However, disadvantages become conspicuous in terms of required quality of materials for apparatus and heat efficiency at a temperature above 350°C.
In the above, an embodiment of a batch process for the present invention is described. In the following, an example of a continuous process will be described.
In Fig. 4, flyash is fed to a rotary-screw mixing extruder at a rate of 100kg(about 0.1m 3 At the same time, an aqueous 3.5N sodium hydroxide solution is fed to the mixer at a rate of 50 liters/hr. A resulting slurry is fed to a pressure type screw-agitation mixing reactor (3) with a screw pump The reactor is provided with a jacket of a heating medium and heated to 1500C. The inner pressure of the reactor is kept at 5 atm (gauge) mainly by heating.
The slurry is discharged after 40-minute residence in the S* reactor and delivered to a flash evaporator where a i" certain amount of water is removed by evaporation, which amount corresponds to about 10 wt.% of the flyash fed at 100kg/hr. The remaining slurry is fed to a similar type of a pressure type screw agitation-mixing reactor with a screw pump and treated at 150°C, 5 atm(gauge) for 40 minutes, and then about kg/hr of water is evaporated in a flash evaporator Then, 20 the remaining slurry is fed to an agitation-mixing reactor (9) with a pump Although the reactor is heated also to 150C, it is not closed unlike the reactors( 3 and and water is withdrawn gradually from an exit and midway vents. The slurry fed with a pump loses most of the water during the residence of 40mins in the reactor At the exit of the reactor it is not in a slurry state, but is a product zeolite in a solid and discrete form. This is fed to awashing tower (10) andwashed with an aqueous solution of calcium chloride. By this washing, small amount of unreacted sodium ions remained in the product are washed away and, at the same time, part of the sodium in the zeolite is replaced with calcium. Alternatively, sodium ions can be removed by washing with an aqueous diluted hydrochloric acid solution. The resulting slurry is delivered to a belt-press dehydrator (12) with a screw pump (11) to be compressed and dehydrated and then transferred to a drier (14) via a belt conveyer (13) to be dried and to yield a final product Artificial zeolite with a conversion of 57% is obtained in the amount of 1.25 times the weight of the raw material flyash.
It should be noted that pressurization is not critical to the present invention, though the reactors were operated at a pressure of 5 atm as described above, which pressure was caused by setting the temperature to 150c in the presence of water. In fact, the intended reaction to form zeolite progresses by heating at 150°C under an atmosphere of steam without pressurization.
Claims (4)
1. A process for preparing artificial zeolite comprising the steps of mixing x kilograms of incineration ash or any other aluminosilicate- containing substance with y liters of an aqueous solution of alkali metal hydroxide having a concentration of 1 N or higher in a proportion, y/x, of 0.1 to 1.5 (liter/kg) to prepare a slurry; and heating the slurry to cause a zeolite-forming reaction wherein water is continuously or intermittently removed by evaporation so that a decrease in a concentration of alkali which would otherwise naturally occur with a progress of S 10 the reaction is at least suppressed to thereby facilitate the reaction. Ile
2. The process of claim 1, wherein the heating takes place at a temperature of higher than 1000C and at most 3500C.
3. The process of claim 1 or 2, wherein a reaction mixture obtained after the reaction is subjected to a washing process to remove alkali without being subjected to a liquid separation process.
4. The process of claim 1 or 2, wherein the reaction mixture obtained after the reaction is not a highly viscous slurry containing water glass produced by a side reaction, but is in a solid form which is easy to wash. 00•• -hi The process of claim 1 or 2, wherein the incineration ash is flyash produced by combustion of coal, active sludge, paper sludge, or garbage. K.E.M. CORPORATION By its Registered Patent Attorneys Freehills Carter Smith Beadle 18 December 2002
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU44700/99A AU768253B2 (en) | 1999-08-24 | 1999-08-24 | Process for preparing artificial zeolite by a slurry reaction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU44700/99A AU768253B2 (en) | 1999-08-24 | 1999-08-24 | Process for preparing artificial zeolite by a slurry reaction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU4470099A AU4470099A (en) | 2001-03-01 |
| AU768253B2 true AU768253B2 (en) | 2003-12-04 |
Family
ID=3731913
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU44700/99A Ceased AU768253B2 (en) | 1999-08-24 | 1999-08-24 | Process for preparing artificial zeolite by a slurry reaction method |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU768253B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5296208A (en) * | 1992-08-07 | 1994-03-22 | Uop | Molecular sieve synthesis |
-
1999
- 1999-08-24 AU AU44700/99A patent/AU768253B2/en not_active Ceased
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5296208A (en) * | 1992-08-07 | 1994-03-22 | Uop | Molecular sieve synthesis |
Also Published As
| Publication number | Publication date |
|---|---|
| AU4470099A (en) | 2001-03-01 |
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