RU2698369C1 - Ceramic mixture for making construction articles - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to production of construction ceramics and can be used in making wall and facing articles: bricks, stones, tiles, slabs and blocks. Ceramic mixture contains low-plastic clay, unplasticized polyvinylchloride wastes (PVC-U wastes), sheet glass scrap and boric acid, with the following ratio of components (wt. %): low-clastic clay - 70–90.0; glass waste - 5.0–15.0; boric acid - 2.5–5.0; PVC-U wastes - 2.5–10.0. Products are produced using semi-dry pressing technology, which will allow to carry out the process cycle without charge and drying of raw material.

EFFECT: technical result of invention is increase of bending products strength at reduction of power consumption due to exclusion of charging material rest and raw material drying stages, as well as reduction of items burning time.

1 cl, 1 tbl, 5 ex

Description

Ceramic mixture refers to the production of building ceramics and can be used in the manufacture of wall and facing products: bricks, stones, tiles, plates and blocks.

Known ceramic mass [1], which includes loam, expanded clay, an iron-containing additive and a burnable additive. Ground iron waste of ammonia production — spent catalyst — was taken as an iron-containing additive, and liquid waste of expanded polystyrene production (mother liquor) was used as a burn-out additive, with the following ratio of components of the ceramic mass, wt. %: loam 69.35-70.5; expanded clay clay 23-23.5; iron-containing waste - a spent catalyst for the production of ammonia, ground to a specific surface of 200 m ² / kg 1.25-1.5; liquid waste from the production of expanded polystyrene with a density of 1.014 g / l 4.5-6.4. The advantages of this ceramic mass are the ability to form products at a pressure of 2.5 MPa and the possibility of firing at a temperature of 950 ° C. The disadvantages of this composition are the relatively low compressive strength of products (30.8 - 45.2 MPa), as well as the complexity and energy intensity of production associated with grinding iron-containing waste to a specific surface of 200 m ² / kg, as well as drying at a maximum temperature of 75 ± 5 ° C for 72 hours.

Known raw material mixture for the manufacture of bricks [2], including clay, quartz sand, particle size 2.0-2.2, a burnable additive, additionally containing silica-containing slurry waste from the processing of spent vanadium catalyst for sulfuric acid production, and as a burn-out additive containing a mixture of wood sawdust crumbs of rubber regenerate of the recycling process of disposable automobile spikes, hydroxypropyl cellulose with the ratio of the indicated components of the burnable additive: 1: 0.1-0.3: 0.01-0.02 the following component ratio, wt. %: clay 73.0-87.0, specified quartz sand 9.0-16.0, sludge from a spent vanadium catalyst processing process 2.0-5.0, said burn-out additive 2.0-6.0. This raw mix allows to obtain products with a thermal conductivity of 0.28-0.32 W / (m⋅ ° С), however, they have low compressive strength (17.4-18.1 MPa) and bending (3.3-3, 7 MPa). The production of products according to the composition of this raw mix is energy intensive (drying for 54-58 hours at a temperature of 154-161 ° C and firing 27.8-29.5 hours at a maximum temperature in the firing zone of 990-1000 ° C). The need for aging the mixture for 14 days increases the duration of the technological cycle.

Known ceramic bricks, stone [3], made of a mixture containing loam or clay, fading pore-forming components and cleaners. Coal fines and / or sawdust fractions from 0.2 to 3.5 mm and polystyrene foam granules from 1.0 to 4.5 mm were used as burnable pore-forming components, and sand with a fineness modulus from 0.3 to 2.2, while the ratio of components in the charge is by volume in%: coal fines and / or sawdust - 2-10, polystyrene granules - 10-35, sand - 3-20, loam and / or clay - the rest. The thermal conductivity of these products is 0.29 W / (m⋅ ° С) for ceramic brick and 0.34 W / (m⋅ ° С) for ceramic stone. The disadvantages of this composition are low compressive strength (100.6-107.8 kgf / cm2 or 9.9-10.6 MPa) and bending (16.0-18.0 kgf / cm2 or 1.7-1.8 MPa).

Closest to the proposed solution is a ceramic mixture for the manufacture of building bricks [4], including clay, quartz sand with a particle size of 2-2.5, a burnable additive, according to the invention, primary, secondary or recyclable polymer wastes of enterprises using the production and processing of polymers - polyvinyl chloride, polypropylene, polyethylene, polyethylene terephthalate, polyamide-6, polymer composite materials based on them in the form of particles with a dispersion of 0.1-2.0 mm at the following content of the components of the mixture, in wt. %: clay 75.0-85.0; silica sand 13.0-15.0; polymer waste 2.0-10.0. This raw mix allows to obtain products with a thermal conductivity of 0.34-0.39 W / (m⋅ ° С), however, they have low compressive strength (35.4-37 MPa) and bending (4.8-5.4 MPa ) The production of products according to the composition of this raw mix is energy intensive (drying for 54-58 hours at a temperature of 154-161 ° C and firing 27.8-29.5 hours at a maximum temperature in the firing zone of 990-1000 ° C). The need for aging the mixture for 14 days increases the duration of the technological cycle.

The technical problems to which the invention is directed are to increase the bending strength of products while reducing energy intensity by eliminating the stages of aging the mixture and drying the raw material, as well as reducing the firing time of the products.

To achieve the objectives, it is proposed to use waste from unplasticized polyvinyl chloride (non-PVC-W waste) as a burnable additive and use glass break and boric acid using additional semi-dry pressing technology as additional additives, which will allow to carry out the technological cycle without aging the mixture and drying the raw material. The most effectively posed tasks are solved using the following composition of the ceramic mass (in wt.%):

Low plastic clay - 70-90.0; Glass battle - 5.0-15.0; Boric acid - 2.5-5.0; NPVH waste - 2.5-10.0.

The present invention provides for the use of clay of the Suvorot deposit of the Vladimir region, containing in its composition the following compounds (in wt.%): SiO ₂ = 67.5; Al ₂ O ₃ = 10.75; Fe ₂ O ₃ = 5.85; CaO = 2.8; MgO = 1.7; K ₂ O = 2.4; Na ₂ O = 0.7. This clay has a plasticity number of 5.2 and is classified as low plastic (according to GOST 9169-75).

As a glass battle, it is supposed to use a battle of sheet window glass of the following composition (in wt.%): SiO ₂ = 73.5; CaO = 7.4; MgO = 1.9; Na ₂ O = 11.1; K ₂ O = 5.2; Al ₂ O ₃ = 0.9, This additive is the source of the vitreous phase, which is formed during firing, fills large pores and voids in the material, which reduces water absorption and increases frost resistance, and at the same time acts as a binder, increasing the strength characteristics of ceramics.

As an additive that increases the amount of the vitreous phase formed, boric acid of grade B grade 2 is used (GOST 18704-78). The introduction of this component can further increase the strength and frost resistance, as well as reduce water absorption, including due to the effect of self-glazing of ceramics arising from the joint introduction of glass breakage and boric acid.

Waste NPVH, in particular the waste of building profiles and finishing panels, are introduced into the mixture as a burnable additive to increase porosity and reduce the thermal conductivity of the resulting ceramics, which increases the energy efficiency of products. The self-glazing effect of the surface will make it possible to convert open pores formed during the burn-up of NPVH waste into closed ones to maintain relatively low water absorption and sufficient frost resistance of products.

The amount of added additives also affects the achievement of objectives. When introduced into the mixture of less than 5 wt. % glass battle and less than 2.5 wt. % boric acid there is a slight hardening of the material with almost constant water absorption, which implies an insufficient amount of the glassy phase formed. The introduction of more than 15 wt. % glass break leads to the filling of most of the pores in the material with a glassy phase, which makes the introduction of a burn-out additive impractical. With the introduction of more than 5 wt. % boric acid with a glass break less than 10 wt. % practically does not change the properties of ceramics in comparison with compositions containing 2.5 wt. % boric acid. With the introduction of boric acid in an amount of more than 5 wt. % together with glass battle in the amount of 10 wt. % and higher leads to warpage of products. With the introduction of less than 2.5 wt. % NPVH waste material properties practically do not change, and when introduced above 10 wt. % of NPVH waste generates an excessive amount of pores, which reduces strength and frost resistance. Also, with the introduction of more than 10 wt. % of NPVH waste in the volume of material and on its surface there are traces of additive burnout.

The implementation of the claimed invention is preferred by the following technology:

Unplastic clay, glass breakage and NPVH waste are preliminarily crushed to obtain particles less than 0.63 mm in size, and then dried to constant weight. Then these components are mixed in the required proportions with each other with the addition of the required amount of boric acid. The resulting mixture is mixed with water to obtain a molding moisture content equal to 8 wt. % From the prepared molding material at a pressure of 15 MPa, a raw material is obtained which, without drying, is fired at a temperature of 1050 ° C.

The validity and advantages of the claimed invention are based on the measurement of physico-mechanical and operational performance of ceramics based on a mixture with a content of from 5 to 15 wt. % glass battle, from 2.5 to 5 wt. % boric acid, from 2.5 to 10 wt. % NPVH waste and are illustrated by the following examples:

1. To 82.5 wt. % maloplastic clay add 5 wt. % glass battle, 2.5 wt. % boric acid and 10 wt. % NPVH waste, mix and receive material according to the specified technology;

2. To 80 wt. % maloplastic clay add 10 wt. % glass battle, 5 wt. % boric acid and 5 wt. % NPVH waste, mix and receive material according to the specified technology;

3. To 85 wt. % maloplastic clay add 10 wt. % glass battle, 2.5 wt. % boric acid and 2.5 wt. % NPVH waste, mix and receive material according to the specified technology;

4. To 82.5 wt. % maloplastic clay is added on May 10,% glass break, 5 wt. % boric acid and 2.5 wt. % NPVH waste, mix and receive material according to the specified technology;

5. To 77.5 wt. % maloplastic clay add 15 wt. % glass battle, 5 wt. % boric acid and 2.5 wt. % NPVH waste, mix and receive material according to the specified technology;

The properties of the materials obtained using the known and proposed compositions of the ceramic mixture are shown in table 1.

Information sources:

1. Patent for invention No. 2614341, class. СВВ 33/132, С04В 33/14, 2017

2. Patent for invention No. 2620677, class. С04В 33/16, С04В 38/06, С04В 33/132, 2017

3. Patent for invention No. 2120923, class. С04В 33/00, С04В 33/02, С04В 38/06, С04В 33/30, 1998

4. Patent for invention No. 2596027, class. СВВ 33/132, С04В 33/16, С04В 38/06, 2016

Claims (2)

Ceramic mixture for the manufacture of building products containing clay and a burnable additive, characterized in that low-clay clay is used as clay, unplasticized polyvinyl chloride waste (NPVH waste) is used as a burnable additive, and glass breakdown and boric acid are additionally introduced, in the following ratio of components, wt. %: Low plastic clay  70-90.0 Glass battle  5.0-15.0 Boric acid  2.5-5.0 NPVH waste  2.5-10.0