RU2386605C1 - Method of making ceramic filter element from composite material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to ceramic materials science, specifically to a method of making ceramic filter elements. A charge mixture containing the following in wt % is prepared: ceramic filler 70-80, wollastonite 3-8, serpentinite 5-7, copper oxide 1-4, dextrin 3-4, aluminoboronphosphate binder 5-10, water (over 100%) 5-10. The charge mixture is dehydrated to moisture content of 1-1.5% and granulated. Optapix PAF 35 binder and bentonite are added and a moulding composition containing the following in wt % is obtained: charge mixture 95-97, bentonite 3-5, Optapix PAF 35 (over 100%) 8-12. The moulding composition is seasoned at room temperature and granulated. Workpieces are moulded at pressure below deformation pressure of the granules. The workpieces are kept under natural conditions and thermally treated at temperature 1200±50°C. The ceramic filler used is selected from electrocorundum, disthene sillimanite thermally pretreated at 1600±50°C, silicon carbide or mixture thereof.

EFFECT: increased gas permeability, which provides high efficiency of filter elements.

3 cl, 3 tbl, 1 ex

Description

The invention relates to ceramic materials science, in particular to the production of porous ceramic materials used in the manufacturing processes of filter elements for cleaning liquid and gaseous media.

Increased performance requirements for filter systems, especially when filtering hot industrial exhaust gases, determine the need to create filter elements from mixtures, which, as a result of technological processes, allow to construct the structure of materials of finished products with normalized physical, mechanical, chemical properties and heat resistance.

In world practice, the solution of a set of operational characteristics, in some cases conflicting in one product, is implemented by creating composite materials. (RU 2204542, 05.20.2003, US 7244685, 07/17/2007, US 7250126 B2, 07/31/2007, WO 2007021705 A2, 02.22.2007, WO 2007028743 A1, 03.15.2007)

A common method for producing porous, permeable ceramics is the molding of a mixture consisting of a fractionated filler of a ceramic binder, or its predecessor, a technological binder followed by heat treatment at temperatures determined by the chemical composition of the mixture components (K. Smirnov, Porous ceramic for filtration and aeration. M. : Stroyizdat, 1968-196 p .; Mogilievsky EI Burtsev VI Technology of manufacturing and testing ceramic filters for refining alloys. Refractories and technical ceramics and №1 M., 2000, pp 43-45, SU 1654290 A1, 07.06.1991;.. RU 2182568, 20.05.2002; RU 2231504 C1, 27.06.2004).

The technological parameters of the manufacture of filter elements are mainly determined by the dispersion and form of the filler, the type of ceramic binder or its precursor, the structural form of the components of the molding mixture, possible volumetric changes in the material during its structural reorganization or chemical interaction of the components of the composite material to obtain a porous, permeable ceramic material for the intended purpose.

A search in patent and informational periodical publications made it possible to identify an analogue closest to the claimed object for the technical task being solved - a prototype, including obtaining a molding mixture containing components, wt.%:

Electrocorundum 80 Kaolin eleven Alumina 2 Gypsum 7 70% H ₃ PO ₄ (over 100%) 10,

molding and heat-treated at temperatures of 1200 ^° C (TP Salihov, V.V.Kan et al., "Alumina ceramics filter for phosphate binders." Glass and Ceramics, №8, 2008 s.28-31)

A disadvantage of the known technical solution is that, with the satisfactory strength of the resulting porous systems provided with a phase composition, the technological parameters of the formation of the microstructure do not allow the production of large-sized filter elements with high gas permeability, which determines the filtration processes in materials with achieved porosity.

The aim of the proposed technical solution is to develop a method of manufacturing a ceramic filter element from a composite material with a high coefficient of gas permeability at a selected fractional composition of the filler.

To this end, in a method of manufacturing a ceramic filter element from a composite material, including preparing a molding material containing a fractionated ceramic filler, a structure-forming powder and fiber component, a phosphate binder, a high molecular weight organic binder, drying, molding of products, heat treatment at a temperature of 1200 ± 50 ° C, previously charge mixture is made from powder structure-forming components containing serpentinite and copper oxide, the mixture is moistened with aluminum with an orphosphate binder, a fractionated ceramic filler is introduced, a binder in the form of dextrin powder is added, the mixture is homogenized, a fiber-forming component in the form of wollastonite is introduced, moistened in the following ratio of ingredients to dry weight, wt.%:

Ceramic filler 70-80 Wollastonite 3-8 Serpentinite 5-7 Copper oxide 1-4 Dextrin 3-4 ABFS 5-10 Water, in excess of 100% 5-10,

the resulting mixture mixture is dehydrated to a moisture content of 1-1.5% and granulation is carried out, OptapixPAF35 binder and bentonite are introduced into the granulated mixture, the molding material is obtained in the following ratio, wt.%:

Granular mixture 95-97 Bentonite 3-5 Optapix PAF 35, in excess of 100% 8-12,

curing is carried out at room temperature, the molding material is granulated, the workpieces are molded at pressures below the granule deformation, the workpieces are kept under natural conditions and heat treated.

The essence of the claimed technical solution consists in an experimentally verified sequence of operations that do not change the functional purpose of the components of the composite material, the established concentration limits for chemical composition when organizing the complex process of obtaining large-sized, ceramic filter elements of a given geometry and mass-dimensional characteristics with a uniform distribution of structure-forming elements of a porous permeable material, allowing d Stich goal.

Based on experimental studies in the implementation of the technical process can be used to obtain identical characteristics:

- ceramic fractional filler is used from a number of electrocorundum, distensillimanite, previously heat-treated at a temperature of 1600 ± 50 ° C, silicon carbide or a mixture thereof;

- dextrin in the form of potato starch cold swelling brand Solvitose PLV.

An example implementation of the method.

The process was used for the manufacture of tubular filter elements of a test tube type with dimensions h = 1050, D _nar = 55, d _ext = 51.5 (mm).

In the manufacturing process used source materials:

Electrocorundum fractions 125-250 microns

Wollastonite

Serpentinite

Copper oxide

Dextrin brand Solvitos PLV

Alumoborophosphate binder (ABFS)

Bentonite

Optapix PAF 35, film type binder

Water is tap.

The sequence of operations for the manufacture of filter elements was maintained regardless of the percentage of ingredients.

The calculated amount of serpentinite and copper oxide was loaded into a high-energy mixer of the “Airich” type and mixed for 2-3 minutes. An aluminoborophosphate binder of 70% concentration was introduced into the resulting mixture and homogenization was performed within 3-4 minutes, followed by the introduction of fractionated electrocorundum and mixing was carried out for 5-10 minutes.

After adding a binder in the form of dextrin powder and subsequent homogenization for 3-4 minutes, the resulting powder mixture was transferred to a Z-shaped mixer, wollastonite was added and mixing was carried out while moistening with water for 30-40 minutes. The resulting mixture mixture was dehydrated to a moisture content of 1-1.5% by calcination at 120 ± 20 ° C. With a mass of the charge mixture equal to 10 kg, the dehydration time was 60 min.

The dehydrated charge mixture was granulated by sieving through a sieve with a mesh size of 1 mm.

To obtain a molding mass, the operation of mixing in a Z-shaped mixer a granular charge mixture with bentonite and a Optapix PAF 35 film-type binder was carried out. The time for obtaining a homogeneous mass was 25-30 minutes.

Before molding the molding material, it was aged at room temperature for 20-24 hours and granulated through a 1 mm sieve.

The blanks were formed by hydrostatic pressing using flexible polyurethane shells with a total pressing pressure of 15–20 MPa. The resulting blanks were kept in natural conditions for 20-24 hours and subjected to calcination in air at a rate of temperature rise of 50-100 ° s / h to a temperature of 1200-50 ° C with isothermal exposure at a maximum temperature of 2-3 hours.

The compositions of the charge mixtures, the molding material and the characteristics of the materials of the filter elements are presented in tables 1, 2, 3.

These tables show that the proposed method allows to obtain the structure of a porous material with high permeable porosity. The high coefficient of gas permeability ensures high performance of the elements with a small hydraulic resistance, which increases the reliability of the operational characteristics of the filtering systems as a whole.

The inventive method is carried out on standard technological equipment with the possibility of obtaining a structure with a given permeable porosity, is easily controlled, and technological parameters guarantee the stability of the quality of the products obtained.

Table 1 Components of a granular charge mixture The content of components, wt.% Mix 1 Mix 2 Mix 3 Electrocorundum (fraction 125-250 microns) 70 75 80 Wollastonite 8 5.5 3 Serpentinite 5 6 7 Copper oxide four 2.5 one Dextrin 3 3,5 four ABFS 10 7.5 5

Table 3 Characteristic Proposed Technical Solutions Prototype one 2 3 Shrink% 0 0 0 0 Porosity,% 47 43 39 37.21 The coefficient of gas permeability, microns ² 60.1 57.5 55,2 8.81 The maximum pore size, microns ² 64 60 57 69.1

Claims (3)

1. A method of manufacturing a ceramic filter element from a composite material, comprising preparing a molding material containing a fractionated ceramic filler, a structure-forming powder and fiber component, a phosphate binder, a high molecular weight organic binder, drying, molding the product, heat treatment at a temperature of 1200 ± 50 ° C, characterized in that a charge mixture is preliminarily made from powder structure-forming components containing serpentinite and copper oxide, the mixture is moistened yayut alyumoborfosfatnoy ligament administered graded ceramic filler, a binder is added in the form of dextrin powder mixture is homogenized, injected structurally forming fibrous component in the form of wollastonite, moistened with the following ratio of ingredients on a dry weight, wt.%:
Ceramic Filler 70-80
Wollastonite 3-8
Serpentinite 5-7
Copper oxide 1-4
Dextrin 3-4
ABFS 5-10
Water over 100% 5-10
the resulting mixture mixture is dehydrated to a moisture content of 1-1.5% and granulation is carried out, Optapix PAF 35 binder and bentonite are introduced into the granulated mixture, the molding material is obtained in the following ratio, wt.%:
Blend mixture 95-97
Bentonite 3-5
Binder
Optapix PAF 35 over 100% 8-12
curing is carried out at room temperature, the molding material is granulated, the workpieces are molded at a pressure below the granule deformation, the workpieces are kept under natural conditions and heat treated. 2. The method according to claim 1, characterized in that the ceramic fractional filler is used from a number of electrocorundum, distensillimanite, previously heat-treated at 1600 ± 50 ° C, silicon carbide or a mixture thereof. 3. The method according to claim 1, characterized in that they use dextrin in the form of potato starch cold swelling brand Solvitose PLV.