RU2230778C1 - Method of preparing granulated synthetic zeolite-containing synthetic detergent component - Google Patents

Abstract

FIELD: synthetic detergents.

SUBSTANCE: superfine X-type zeolite is mixed with carboxymethylcellulose in the form of dry powder with particle size <1.5 mm or aqueous solution in amounts of 5-10%. Mixture is extruded to form granules 4 mm in diameter and 5-8 mm long, which are dried on tape drier, crushed, and sorted. Fines of granulated synthetic zeolite-containing synthetic detergent component below 0.2 mm in size are returned for mixing with binder.

EFFECT: enabled production of detergents by dry mixing of starting components.

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Description

The invention relates to a technology for producing granular zeolite components of synthetic detergents (CMC) and may find application in the production of CMC in the chemical industry.

Synthetic zeolites, which are used as ion exchangers that replace partially or fully phosphates in synthetic detergents, are widely used in the production of CMC.

However, the introduction of zeolites in the composition of CMC is associated with certain difficulties, since zeolites are a highly dusting powder with a particle size of 2-8 μm, which complicates the technology, worsens working conditions and reduces the quality of the final product. According to GOST 25644-83, granules with a size in the range of 0.2-2.5 mm are standard in the production of synthetic detergents.

The use of powdered zeolite, thus, completely eliminates the possibility of preparing CMC by the dry displacement method of the raw materials included in the detergent receptor.

A known method of producing granular free-flowing components of CMC with a high bulk density containing 15-20% ethoxylated with ethylene oxide alcohols C ₁₂ -C ₂₄ or other nonionic hydroxyalkylated surfactants, 5% anionic surfactants, 40-80% inorganic fillers (sodium tripolyphosphate, type A zeolite , sodium metasilicate, soda, sodium sulfate), 0.5-10% polyphosphonic acids, polycarboxylic acids, sodium toluenesulfonate, CMC, optical brightener and 10-20% adsorption or crystallization water (application Germany No. 3434864, M. class. C 01 D 11/02, 1986).

The disadvantages of this method are:

1. The content of environmentally harmful phosphorus compounds, which, falling into natural bodies of water, cause their poisoning (eutrophication).

2. The use in the composition of the composition of many types of raw materials, which significantly complicates the process of production of granular product.

A known method of producing granular zeolite - component CMC containing carbonates and zeolites, which provides:

- preparation of zeolites of types A or X in the form of powders by hydrothermal crystallization of mixtures of sodium silicate and aluminate, separation of the mother liquor, washing and drying of the zeolite (average particle size of the zeolite is less than 15 μm);

- the preparation of a suspension consisting of 20-60% zeolite, 5-30% soda (sodium carbonate), 5-15% sodium silicate and 25-60% water and lowering the viscosity of this mixture;

- spray drying the resulting mixture with the formation of spherical granules with a moisture content of 2-16 wt.% and cation exchange capacity (CBS) for CaO 170-190 mg / g of product;

- mixing the obtained granules with a nonionic surfactant (US Patent No. 4,406,808, CL 252-91, 1983).

This method has the following disadvantages.

1. The ability to obtain granular zeolite for CMC by spray drying an aqueous suspension of raw materials only in the form of microspherical granules 60-200 microns in size, which makes it impossible to use such a product in the preparation of CMC by dry mixing.

2. The use of type X coarse neolith as a raw material for the preparation of granules, which obviously has a 20–30% lower KOS in CaO than type A zeolite, and because of the presence of zeolite particles up to 15 μm in size, lower KOS in MgO.

3. The use of zeolites (raw materials) with a particle size of up to 15 microns, because the smaller this size, the higher the zeolite KOS for both CaO and MgO is higher and, preferably, the use of powdered zeolite with a crystal size of not more than 4 microns.

A known method of producing granular zeolite filler for synthetic detergents (RF patent No. 2016846, C 01 B 33/34, 1994), which involves mixing solutions of silicate and sodium aluminate at a molar ratio of SiO ₂ / A ₂ O ₃ equal to 2.0- 2.5; crystallization of the resulting silica-aluminum hydrogel into type A zeolite at a temperature of 60-100 ° C for 0.4-6.0 h and spray drying of a suspension of zeolite in the mother liquor with a concentration of: 100-250 g / l zeolite, 55-110 g / l NaOH , 5-30 g / l SiO ₂ in the flue gas stream containing CO ₂ . In this case, complete or partial neutralization of sodium hydroxide occurs, leading to the formation of a granular zeolite filler for CMC, containing: 50-60% type A zeolite, 25-30% soda, 2-8% sodium silicate, 2-5% sodium hydroxide and 2 -15% water. The product has a CBS of CaO of 190-200 mg / g and a fractional composition of 80-200 microns.

One of the disadvantages of this method is the ability to obtain a zeolite-containing component of CMC only in the form of microspherical granules (60-200 μm), which makes it impossible to use them in the production of CMC by dry mixing. Another is low CBS for MgO, as zeolite type A (NaA) has high ion-exchange properties in the exchange of Na ⁺ cations for Ca ²⁺ and low in the exchange of Na ⁺ for Mg ²⁺ .

A known method for producing granular synthetic zeolite used in CMC formulations (AS USSR No. 1159885, C 01 B 33/28, 1985). The method involves spraying a liquid zeolite with a pneumatic nozzle onto a powdery zeolite while stirring it in a device with a vibro-boiling layer An aqueous suspension of zeolite with a binder is used as a liquid medium with a ratio of solid and liquid phases equal to (0.2-1.0): 1. As a binder, aqueous solutions of surfactants are used. A granular zeolite with a bond is obtained. conductive with a particle size of 0.2-2.5 mm.

The known method has the following disadvantages.

1. The complexity and multi-stage technology for producing granules associated with the need to prepare and use only aqueous suspensions of zeolite and surfactants as a binder.

2. High energy consumption, because spraying occurs at a ratio of (0.2-1.0): 1 between the solid and liquid phases.

3. The inability to obtain granules containing less than 15% water (humidity), because the method does not provide for the drying of granules at a temperature above 100 ° C. As a result, the finished product crumbles and loses flowability during storage and transportation, which makes it impossible to use it in CMC production by dry mixing and significantly complicates its use in the production of CMC by the “tower” method (through repulpation and subsequent spray drying).

The closest in technical essence and the achieved result to the proposed invention is the “Method for producing granulated synthetic zeolite” (A. S. USSR No. 1156726, 01 J 2/20, 2/28; C 01 B 33/28, 1985) , which is chosen for the prototype.

According to this method, a zeolite with a moisture content of 20-40% is mixed with a binder - powdered carboxymethyl cellulose (CMC), taken in an amount of 0.5-5.0 wt.% Calculated on dry zeolite and having a particle size of not more than 1.5 mm The mixture is extruded through a screw granulator grate, and the obtained granules with a diameter of 4.5 mm and a length of 6-9 mm are dried in a fluidized bed apparatus at 80 ° C and a fluidization number of 0.8-1.2. Get granular zeolite with a binder with a residual moisture content of 5% and a mechanical strength of 7-10 kgf / cm ² (0,07-0,1 kgf / mm ² ).

This method has the following disadvantages.

1. The use of a binder in an amount of 0.5-5.0 wt.% Based on dry zeolite does not provide zeolite granules with a binder of the necessary mechanical strength. Granules are destroyed to a fraction of less than 0.2 mm during storage and transportation.

2. The use of a binder in an amount of 0.5-5 wt.% Based on dry zeolite does not allow us to talk about a granular product as a complex compound including zeolite and CMC (surfactant) in the ratio required for the production of CMC. In the CMC formulations, the zeolite is 10-15 wt.%, And the desired CMC content is about 1 wt.%. When the granulated zeolite obtained by the known method is introduced, if the CMC contains 10-15 wt.% Zeolite, the CMC content is only 0.05 -0.5 - 0.075-0.75. Thus, CMC must be introduced as a separate type of raw material directly into the CMC.

3. Zeolite granules with a binder diameter of 4.5 mm and a length of 6–9 mm cannot be used to obtain CMC by dry mixing, as well as dust (fraction <0.2 mm) formed during storage and transportation. As already noted, a particle size of granular zeolite of 0.2-2.5 mm is required.

4. The use of only powdered CMC is provided as a binder, which complicates the process of mixing with zeolite and leads to inhomogeneity of the granules and, as a result, can lead to their mechanical destruction with such a small amount of binder.

5. Drying in the apparatus of a fluidized bed of extruded granules leads to the formation of microcracks on the granules and a decrease in their mechanical strength.

6. The use of zeolite type A, as well as the use of coarse zeolite type X, leads to the production of a granular component CMC having a low KOS in MgO.

The aim of the invention is to develop a method for producing granular synthetic zeolite-containing component CMC with improved quality indicators in terms of particle size distribution (0.2-2.5 mm), mechanical strength of granules 0.6-0.8 kg / mm ² (60-80 kg / cm ² ), high CBS for MgO, which has a balanced complex composition (zeolite + surfactant), i.e. such a component of CMC, which can be used in the production of detergents by dry mixing of raw materials.

This goal is achieved in that highly dispersed zeolite type X (preferred crystal size is 1-3 μm) is mixed with carboxymethyl cellulose, taken in the form of a dry powder with a particle size <1.5 mm, or an aqueous solution in an amount of 5-10 wt.%, In in terms of dry zeolite. The mixture is extruded, granules with a diameter of 4 mm and a length of 5-8 mm are dried in a belt dryer, crushed to obtain a fraction of 0.2-2.5 mm and classified. After classification, the crumb fraction less than 0.2 mm in size is again sent for mixing with a binder.

Comparative analysis of the proposed method with the prototype allows us to conclude that the claimed method differs from the known mixture of finely dispersed (predominantly crystal size 1-3 microns) zeolite, namely type X, with carboxymethyl cellulose taken in an amount of 5-10 wt.%, Counting on dry zeolite. Moreover, CMC is used in the form of a dry powder (as in the prototype) or in the form of an aqueous solution. The difference also lies in the drying of extruded granules, which is carried out in a belt dryer at a temperature of 130-180 ° C. And finally, the dried granules are crushed and classified to obtain a fraction of 0.2-2.5 mm, and the smaller fraction formed during crushing is again sent to mixing with a binder.

An analysis of known methods for producing synthetic zeolites of granular and zeolite-containing fillers CMC showed that the preparation of highly dispersed zeolite type X, mixing zeolite with CMC, extruding the mixture to obtain cuttings and then drying them is known. However, only the fact of mixing highly dispersed (predominant crystal size of 1-3 μm) zeolite, namely type X with CMC, taken in an amount of 5-10 wt.%, Counting on dry zeolite, allows drying after drying in a belt dryer at a temperature of 130-180 ° С to obtain mechanically strong granules of the synthetic component CMC. Moreover, such a component of CMC, which has a balanced (optimal) chemical (zeolite / surfactant ratio) composition for use in detergent formulations and high CBS for MgO.

The use of a binder in the form of an aqueous solution of CMC allows us to provide a high degree of homogeneity of the extrudable mixture and, as a result, high strength of the granules. Only new operations of crushing and the subsequent classification of granules lead to the particle size (0.2-2.5 mm) required to ensure the possibility of using the CMC component in the production of detergents by dry mixing of raw materials. The use of a fraction of less than 0.2 mm formed during crushing, again upon receipt of the CMC component, allowed us to create a closed, waste-free, environmentally friendly production scheme.

The essence of the invention is as follows.

A highly dispersed (mainly crystal size of 1-3 μm) type X zeolite (humidity 20-40%) is mixed with CMC taken in the form of a dry powder (particles ≤1.5 mm in size) or an aqueous solution, in an amount of 5-10% of the total mass of dry zeolite with CMC. Mixing is carried out until a homogeneous paste is formed. The paste is extruded through a screw granulator die. The obtained extrudates-cuttings with a diameter of 4 mm and a length of 5-8 mm are dried in a belt dryer at a temperature of 130-180 ° C in a steam-air medium. Get mechanically strong 0.6-0.8 kg / mm ² (60-80 kg / cm ² ) granules containing 90-95 / 10-5 wt.% Type X zeolite and CMC, in terms of dry matter, respectively. Granules are crushed to obtain a fraction of 0.2-2.5 mm and classified by screening. A fraction of less than 0.2 mm is again sent to mixing with a binder. Commodity granular synthetic zeolite-containing component CMC has a high MOC for MgO, high flowability, does not dust, does not break down during transportation and storage and is used in the production of CMC by dry mixing.

Example. 100 g of fine zeolite X with a moisture content of 20% are mixed with 8.9 g of CMC (added as a solution). Mixing is carried out until a homogeneous paste. The paste is extruded through a screw granulator die. The resulting cuttings are dried at 130 ° C in a vapor-air environment. Get mechanically strong 0.6 kg / mm ² (60 kg / cm ² ) granules containing 90 wt.% Type X zeolite and 10 wt.% CMC, calculated on the dry matter. Granules are crushed to obtain a fraction of 0.2-2.5 mm and classified by screening. A fraction of less than 0.2 mm is sent for mixing with a binder.

The data of the remaining examples are presented in the table.

A decrease in the input of a binder of less than 5 wt.% Causes a deterioration in the strength of the granules, an increase in the number of fractions of less than 0.2 mm after crushing and a deterioration in the conditions of storage, transportation and commissioning of CMC.

An increase in binder input in excess of 10 wt.% Reduces CBS no MgO and gives the granules a non-optimal composition (zeolite / surfactant).

The use of any other type of zeolite instead of type X zeolite, even having a high dispersion (the predominant crystal size is 1-3 microns), reduces the minimum of 15–20% CBS by MgO of the finished product.

The temperature regime of 130-180 ° С drying in a steam-air mixture in a tape dryer is due to the operating conditions of real dryers, the need to give granules moisture 5-10% and to prevent combustion of CMC during drying.

Claims (1)

A method of producing a granular synthetic zeolite-containing component SMS, comprising mixing zeolite with a binder - carboxymethyl cellulose (CMC), extruding the mixture and drying the granules, characterized in that fine X-type zeolite with a crystal size of 1-3 μm is fed into the mixture, and carboxymethyl cellulose is used as dry powder or aqueous solution in an amount of 5-10 wt.% in terms of dry zeolite, the granules are dried on a belt dryer at a temperature of 130-180 ° C, crushed to obtain a fractional composition of crumbs of 0.2-2.5 mm , classified, after which the crumb of the granular zeolite-containing component SMS with a size of less than 0.2 mm is again served for mixing with a binder.