Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention re~ e-J t0 a crys-~llirle ty~ eolite
powder having the composition 1.0 -~ 0.2 M2/nO : ~12O3 : 1.~5
0.5 SiO2 y ~12O, wherein M represents a metal cation, n its
valency and y a value of up to 6, and containing 50~ by weight
of particles of a size below a maximum of g.8llm. l~e present invention
also relates to the process for produciny the crystalline zeolite
powder by means of hydrothermal crystallization of an alkali-
aluminate-silicate mixture and to the use of this zeolite powder
in wasking, rinsing and cleaning agents.
Zeolitic molecular sieves with their specific properties
for ion exchange and adsorption have been known for a long time.
Their synthesis is based on heating an aqueous synthesis mixture
having the components a Na2O x b A12O3 x c SiO2 to temperatures
between 50 and 300C. Depending on the composition of the starting
mixture, reaction temperature and reactlon time differently
structured compounds having the general formula Nax Alx Siy 2
(x+y) n H2O are obtained. These compounds can be distinguished
by their X-ray spectra. Sodium can be replaced by other mono-
valent or divalent metal cations.
- ~or use as adsorbents, catalyst supports or ion
exchangers the molecular sieves are converted into molded
articles by means of a suitable binder. The production of the
molded articles means a great technical expenditure while
simultaneously reducing the effect as a result of the proportion of
binder. The rate of reaction also is substantially slowed down
due to the long diffusion paths, whereby, for example, the drying
of organic liquids is rendered cumbersome. Therefore, for
many uses it makes sense to apply the molecular sieve in the
~d form of a powder. The fact that in the molecuLar-sieve synthesis
crystals having an average diameter above approximately 2 ~m are
obtained while a substantial proportion, usually from 3 to 12%
by weight, have a maximum particle .size above ~5 ~m is common
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to the known methods ofproduction (~or example, Ger~an Patent
- l 038 017). This proportion is known as grit, which, according
to DIN 53580, is determined by wet screeniny accordiny to Mocker.
In a product typical of this process it is found that approximately
25% by weight of particles have diameters below lO ~m and 50%
by weight have particle diameters of 13 Ilm (D. W. sreck~ Zeolite
Molecular Sieves, paye 388, John Wiley -~ Sons, New York, London,
Sidney, Toronto, 1974).
The present invention provides a p~ocess by means of
whlch powdered, zeolitic type-A molecular sieves intended for use
as lon exchanyers, for example, as water softeners, can be
synthesized without a proportion of yrit (particles~ 45 ~m) and
with smaller particle sizes. The absence of yrit as well as
a smaller particle size is indispensable for the use of these
molecular sieves within the scope of the invention, for example,
as a phosphate substitute in washing, rinsing and cleansing
agents. Washing and cleansing procedures, particularly in
. machines, require that the molecu].ar sieve remains in suspension
in the wash liqucr (due to low tendency for sedimenta-tion) in
order to attain rinsing without residues on completion of the
procedure.
Accordiny to the present invention there is provided a
; crystalline type-A zeolite powder having, the composition 1.0 +
` 0.2 M2/n-: ~12O3 : 1.85 + 0.5 SiO2 y H2O, wherein M represents ~-
a metal cation, n its valency and y a value of up to 6, and
containing 50~ by weight of particles below a maximum of 4.8 ~m
as well as having-the following particle spectrum
fraction proportion
(~m) (~ by weiyht) ~ :
< 3 lO to 18
< 5 55 to 70
~lO 93 to 99
<15 96 to lO0
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The present invent:ion ~lso provides a pr~cess ~or
producing the crystalline zeolite powder ~ccor~ing to the
invention by hydrothen~al crystallization of an alkali alurninate/
water/silicate synthesis mixkure containing SiO2, Al2O3 and Na2O
and water, if required with a subsequent tempering stage. ~D~ring
the crystallization or in the tempering stage stirring may be
replaced by the action of shearing forces. This process is
characterized in that an aqueous caustic soda solution is heated
to a temperature between 30 and 80C, that, while stirring, a
sodium-aluminate liquor which contains 0.1 to 500 g of NaOH per
litre is heated to a temperature from 30 to 100C and is mixed
with an alkali metal silicate solution having a temperature of 30
to 80C within a period of 10 to 200 minutes while stirring, where-
upon a sodium-aluminate liquor containing 10 to 200 g of A12O3
per litre and 10 to 250 g of Na2O per litre and having a tempera-
ture between 30 and 100C is added within 10 to 200 minutes while
- stirring and that the synthesis mixture thus obtained is allowed-
to crystallize at a temperature between 20 and 175C within at
:~:
least 15 minutes.
In a-preferred manner of carrying out the process
sodium tetrasilicate can be used as alkali metal silicate solution.
In the process according to the invention stirring may
be replaced by the action of shearing forces. Conventional devices -~
`` can be used for this purpose. This conventional measure increases
the particle fineness but is not required for carrying out the
process according to the invention.
In the process according to the invention shearing
forces may be allowed to act on the synthesis mixture, which can
contain the individual components in molar ratios a.s they are
used in known processes (Eor example, German Patent 1 038 017 and
laid-open German Specification 1 095 795), during the crystallixa-
tion and possibly during the subsequent tempering stage.
~y "shearing" is meant any comminut:ing mechanical stress
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oE discrete particles in suspensioll, l.e., a stress which is due
primarily to real shearing action. The shearing can be carrie(l
out continuously or discon-tinuousl~. A turbine irnpeller, for
example, the EKAI'O (a trade mark) turbine impeller, is preferred
as the shear device. Ilowever, shearing can also be performed with
a toothed-disc dissolver, dispensing pump, rotary pump, etc.
While in the present case, the crystallization can be
carried out, for example, at 93C, it has been found to be
advantageous to carry out the tempering at a temperature between
85and 105C in the crystallization mother liquor. Tempering
times between 0.2 and 6, preferably between 0.8 and 4.0, particu-
larly 3 hours are favourable. The tempering time commences at
the point at which t-he crystallizationis completed. This point
is evident from the development of maximum ion exchange capacity,
on attaining maximum X-ray line intensity and an adsorption of
water vapour of approximately 22.5%. In practice the tempering
time is based on an empirical value determined by means of optimum
formulation.
- Shearing forces acting to the end of the crystallization
phase can be so intensified that the average particle diameter
can be reduced to very small values. The values for the maximum
particle size and its percentage in the product can also be
reduced. However, shearing carried out during the tempering phase
exclusively influences the maximum particle size and its
proportion in the.product.
The invention also provides for the use of the
~ crystalline type-A zeolite powder according to the invention
- - as an ion exchanger, for example, for the softening of water,
. particularly as a phospha-te substitute in washing, rinsing
and cleansing agents.~
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These deteryents are combina-tions of surfac~ active
crude washing substances. However, in most cases they also
contain other substan-tially inorganic additives, which con~ribute
-to a successful washing procedure and are necessary for the
production process and for the external quality of the production.
Depending on the use concerned the cornposition of the detergents
varies and depends particularly on the fiber type, coloration and
washing temperature. It also depends on whether -the washing
operation is carried out by hand, for example, in a tub, in a
household washing machine or in a laundry. Most detergents
are pourable powders. However, liquid and pasty products are
also avallable (see Ullmann's Enzyklopadie der technischen Chemie,
Third Edition, Vol. 18 Urban ~ Schwarzenberg, Munich 1967).
The crystalline type-A zeolite powder according to
the invention has the advantage that it is free from grit and
contains smaller particles even during its production. Therefore,
when using it as a phosphate substitute in washing and cleansing
agents it can be easily kept in suspension in the liquors
concerned and can be rinsed out with particular ease from washing
and cleaning machines and their charge without leavinq residues.
The present invention will be further described by
way of the following Examples.
Example 1
560 litres of a solution of caustic soda (Na2O = 63 g
per litre) having a temperature of 70C are put into a tub of
2-cu m capacity.
While stirring with a three-stage Mig impeller 300 litres
of sodium tetrasilicate (~ = 1.35 kg per l;tre) containing 8.0%
of NaO per litre and 26.7% of A12O3 per litre are added within
40 minutes to the solution of caustic soda. The solution remains
clear.
100 litres of an aqueous sodium-aluminate liquor
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having a temperature of 70C and containing 147 g o~ Na2O per
litre and 103 g of A12O3 per lltre are added first to the
solution in 15 minutes, whereupon 900 litres of the same liquor
are added in 98 minutes. The reaction mixture is heated to 85C
andis crystallized for 3 hours. An X-ray-photographically pure
type-A zeolite having the following particle spectrum is
obtained:
fraction proportion
(~m) (~ by weight)
lO < 3 ~m 15
< 5 um 62
<lO ~m 98
<15 ~m 99
The proportion of 50% by weight is below 4.3 ~m. The
particle size is de-termined by measuring with the Coulter coun-ter.
Example 2
Perborate-Containing Detergent
, 45.0~ by weight of sodium aluminium silicate obtained
according to example l (dried for 6 hours at 90C,
water content 16.8% by weight),
20.0~ by weight of sodium perborate,
35.0% by a detergent powder, produced, for example,
by hot-air drying and having the following
composition:
21.0~ by weight of ABS (dodecyl benzene sulphonate),
7.5% by weight of ethoxylated tallow alcohol
(l mole of tallow alcohol + 14 moles of
ethylene oxide),
7.2~ by weight of SO.lp (sodium salt of saturated
substantiallY C18 ~ C22 fatty acids)~
-- 9% by weight of sodiurn tetrasilicate
(Na2O 3.3 sio2?,
4.5~ by weight of magnesium sulphate,
.
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2.0~ by wei~ht of carboxy-methyl cellulose,
0.6% by weight of optical brlc3htener,
9.0% by weight of soluble complexing-agent
salt (for example, sodium citra-te, NTA,
EDTA , sodium triphosphate, POC etc.),
; 35.0% by weight of sodium sulphate
the rest = water.
The detergent was produced by mixing the three
powdered components.
Example 3
Detergent Free from Perborate
2.0% by weight of ethoxylated Cll/C15 oxo alochol
- (1 mole of oxo alcohol ~ 3 moles of ethylene oxicle), )
5.0% by weight of ethoxylated Cll/C15 oxo alochol (1 mole
of oxo alcohol ~ 3 moles of ethylene oxide),+ )
40.0~ by weight of sodium aluminium silicate obtained
according to example 1 (dried for 6 hours at
- - 90C, water content 16.8~ by weiyht),
,
15.0% by weight of soda,
5.0% by weight of sodium citrate,
4.0~ by weight of sodium tetrasilicate (Na2O 3.3 SiO2),
1.5% by weight of carboxy-methyl cellulose,
0.2% by weight of optical brightener,
23.0% by weight of sodium sulphate,
rest = water
) replaceable by tallow alcohol + 5 moles of ethylene oxide,
) replaceable by tallow alcohol ~ 14 moles of ethylene oxide.
The detergent is produced by spraying ethoxylation
products (non-ionicsurfactants) on thepowder particles consis~lng
of the other components.
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