JPS6049124B2 - Method for drying aluminosilicate slurry - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for drying an aluminosilicate slurry used in a granular laundry detergent containing an aluminosilicate.
More specifically, the present invention relates to a method for drying an aluminosilicate suspension slurry containing fine aluminosilicate particles, which greatly reduces the formation of coarse particles due to secondary aggregation of the fine aluminosilicate particles during the drying process.

Traditionally, phosphates such as tripolyphosphate have been widely used as laundry detergent builders, but in recent years it has been pointed out that phosphorus is a contributing factor to environmental problems such as high nutrient content in lakes and red tide. As a result, the amount of phosphates contained in detergents has come to be regulated.

For this reason, alkali builders such as silicates, carbonates, and bicarbonates, and organic builders such as citrates have been proposed as builders to replace phosphates, but these builders have relatively low water hardness. Although it has some effect when the hardness is low, it is not necessarily sufficient when the hardness is high. The use of zeolite, which has the property of capturing Ca ions in hard water, has been proposed as a builder that is sufficiently effective even when water hardness is high (Japanese Patent Application Laid-open No. 50-12381, JP-A No. 50-100378, JP-A-50-100378, (1976-53404).

But a? Reminosilicates are water-insoluble and must be made into extremely fine particles for use as detergent builders. By using fine particles with a particle size of 10 μm or less, preferably several μm or less, the ability to capture Ca ions during washing can be increased, and it is possible to prevent them from adhering to the laundry. Even if it sticks, it can be made inconspicuous. Aluminosilicates are available as powders or slurries in water suspension.

However, in powdered aluminosilicate, primary particles with a particle size of about 0.1 μm to several μm aggregate, and most of them have a particle size of 50 to 400 μm.
Ca ions form secondary particles (coarse particles), and even if they are blended into detergents as they are, the effect of capturing Ca ions will not be sufficient and they will also adhere to the items being washed, which is not preferable. On the other hand, in an aqueous suspension slurry, aluminosilicate particles exist mostly as primary particles, and although they are fluid and easy to handle, the solid content is usually 30 to 40 wt%, which is If the solid content is increased above, the dilatant viscosity increases due to its inherent properties, making it impossible to handle it practically. By the way, most detergent slurries for spray drying have a solid content of about 60 wt% or more, but the solid content is 30 to 4 wt%.
When blending 0wt% aluminosilicate suspension slurry into a detergent slurry containing surfactants and other builders, even if the amount of aluminosilicate is small, if the amount is increased, the detergent slurry prepared The solid content of the slurry will be considerably reduced, and spray drying such a slurry will place a significant load on the drying tower, which will not only reduce drying efficiency but also affect the bulk density and powder properties of the dried detergent particles. Undesirable.

As a method of blending aluminosilicate without reducing the solid content of the detergent slurry, it is possible to spray dry only the aluminosilicate suspension slurry in advance to a semi-dry or dry state, but this method Since agglomeration occurs and secondary particles (coarse particles) are produced, it is not possible to obtain aluminosilicate suitable for detergent formulation. Furthermore, a method has been proposed in which an aluminosilicate slurry and a detergent slurry are spray-dried separately in the same drying space (Japanese Patent Application Laid-open Nos. 53-39307 and 53-51212).
The amount used is limited due to physical properties and dust. As a result of extensive research into the agglomeration mechanism of aluminosilicate particles during the drying process of aluminosilicate suspension slurry, the present inventors found that when aluminosilicate suspension droplets are heated externally, only their surface layer rapidly It was discovered that when the droplet dries, it forms a strong shell, and when it is surrounded by this shell, aggregates (coarse particles) are formed.In order to prevent such aggregation, the inside and outside of the droplet should be made more uniform. We have found that drying is effective, and based on this knowledge, we have completed the present invention.

3 That is, in the present invention, when drying an aluminosilicate slurry containing 10 to 50% by weight of aluminosilicate and 50 to 9% by weight of water, the aluminosilicate slurry is dried under pressure of 5k9/CTl or more.
A method for drying aluminosilicate slurry characterized by heating above 00°C and spray drying at a temperature below 50°C under atmospheric pressure, thereby producing aluminosilicate particles suitable for formulation in detergents. The aim is to obtain the following. Examples of the aluminosilicate that can be used in the present invention include natural and synthetic zeolites.Specifically, 41 natural zeolites include mordenite and clinobutyrolite, and synthetic zeolites include A-type, X-type, Y type etc. can be used, but
Among these, type A, which has a high ion exchange capacity per weight and has nearly cubic particles, is preferred. The aluminosilicate slurry of the present invention has aluminosilicate particles dispersed therein in a diameter of 0.1 to 10 μm, preferably 0.5 to 5 μm, contains 10 to 50% by weight of aluminosilicate, and has a water content of 5% by weight.
Contains 0-9% by weight. If the amount of aluminosilicate is less than 10%, efficient drying cannot be achieved. On the other hand, if it exceeds 50%, the dilatancy viscosity of the slurry is so high that it cannot be sprayed, and if it becomes even higher, there is no need for drying. The spraying conditions employed in the present invention are as follows.

Slurry pressure: 5k9/d or more, preferably 10k9/d
C! If it is lower than i~20k9/Dl5k9/d, particle aggregation cannot be sufficiently prevented.

20k9/C! If it exceeds i, special pressure-resistant equipment is required.

Slurry temperature: 100C or more, preferably 100~
200℃, lower than 100℃, particle aggregation
cannot be adequately prevented.

Spraying atmosphere temperature/pressure: 50°C or less, atmospheric pressure, temperature: 80%RH or less, preferably 60%RH or less,
Spray nozzle: The type of nozzle that can be used is either a swirl chamber type or a centrifugal spray type.

The use of two-fluid nozzles is also possible. As already mentioned,
The aluminosilicate suspension slurry was subjected to conventional spray drying (200
When the temperature rises to ~300°C (spraying into an air stream) and dries, significant agglomeration occurs.

This means that there are 200 to 200 droplets containing a large number of fine r-luminosilicate.
When the droplet comes into contact with high temperature air at 300°C, the surface layer of the droplet dries rapidly, but at that time, the aluminosilicate particles present on the surface agglomerate to form a strong shell, and the droplets are surrounded by this shell.
By drying the entire product in this state, agglomerated coarse particles are formed. On the other hand, in the method of the present invention, the droplets are sprayed from a high temperature state to a low temperature and low pressure state, so that when the droplets are dried from the surface layer, the moisture inside the droplets is transferred to the surface layer. It is thought that particle aggregation is suppressed due to the rapid movement and evaporation of Most of them are in the form of fine primary particles (particle size 0.1 to 10μ).This dry aluminosilicate can be blended into detergent slurry, or it can be mixed with separately prepared granular detergent and powder. They may be mixed.Example Sodium aluminosilicate (Shon Silton D) with an average particle size of 0.7μ
A water suspension containing 40 Wt of BK (manufactured by Mizusawa Chemical Industry Co., Ltd.) was spray-dried under the conditions shown in Table 1, and the proportion of coagulated particles (particle size of 50 μm or more) was measured.

Example 2 - 40W't% of sodium aluminosilicate (Silton DBK, manufactured by Mizusawa Chemical Industry Co., Ltd.) with an average particle size of 4.3μ,
Polyethylene glycol (PE manufactured by Lion Yushi Co., Ltd.)
An aqueous suspension containing 5% of G#400) was spray-dried under the conditions shown in Table 2, and the proportion of aggregated coarse particles (particle size of 50 μm or more) was measured.

Claims (1)

[Claims] 1 Aluminosilicate 10-50% by weight, moisture 50-90%
In drying the aluminosilicate slurry containing % by weight, the aluminosilicate slurry is heated to 100°C or more under pressure of 5 kg/cm^2 or more, and spray-dried at a temperature of 50°C or less at atmospheric pressure. A method for drying aluminosilicate slurry characterized by: