RU2377210C2 - Raw material mixture for production of heat insulating light concrete - Google Patents

Abstract

FIELD: building. ^ SUBSTANCE: invention refers to building and can be implemented at production of building materials for construction of industrial projects, dwelling houses, cottages, agricultural constructions, etc, mainly for heat insulation in form of plates, and also monolithic heat insulation, for example roofs. Raw material mixture for production of heat insulating light concrete consists of, wt %: mineral binding - Portland cement 2-7, wood fibre material 2-7, mineral filler - blown-out vermiculite 2-8, liquid glass 11-20, dust of gas purification of electro-thermal production of silicon and/or ferrosilicon 29-40, water 26-46. The invention is developed in the dependent point of the invention formula. ^ EFFECT: upgraded engineering and economical performance of heat insulating light concrete production. ^ 2 cl, 1 tbl

Description

The present invention relates to the field of construction and can be used in the production of building materials for the construction of industrial facilities, residential buildings, cottages, agricultural buildings, etc., mainly for thermal insulation in the form of plates, as well as monolithic thermal insulation, for example, roofing.

For thermal insulation of the enclosing structures of industrial and residential buildings (walls, coatings and ceilings), inorganic and organic materials are used. The use of thermal insulation materials allows to increase the degree of industrialization of construction works. In prefabricated housing construction, lightweight large panels with insulation are widely used. This makes it possible to reduce the weight of buildings and reduce the need for basic building materials - cement, reinforcing steel and wood. In the vast northern regions of our country, where the cost of transportation is many times higher than the cost of the material itself, it is most effective to build lightweight layered elements consisting of an outer strong shell and an inner layer of porous insulation. For example, in the north, the ability of a material to retain heat is especially important: the amount of fuel consumed for 4-5 years to heat a building is almost equal to the weight of its external walls (see G.I. Gorchakov “Special Building Materials for Thermal Power Engineering”, Izd- in the literature on construction, Moscow, 1972).

Known raw mix for the manufacture of sawdust concrete blocks according to the patent of Russia No. 2039717, MKI ⁶ C04B 28/00, 1992, including wt.%.

Portland cement 20-25 Wood aggregate 50-55 Mineral aggregate 16-20 4-Chlorine, 2,3,5,6-potassium fluorophenolate 0.05-0.10 Water 4-10

As a wood filler use waste processing of any wood species, sawdust, shavings, pre-chopped branches and bark. Mineral aggregate is sand with inclusion of clay particles of not more than 5-10%, pre-ground ash ash of fuel (slag) from thermal power plants and boiler houses. To accelerate the hardening process, especially at temperatures below 15-16 ° C, alabaster (CaSO ₄ · 0.5 H ₂ O) or gypsum (× CaSO ₄ · yCaO) is introduced into the mixture.

An aqueous solution of 4-chloro, 2,3,5,6-potassium fluorophenolate (CTFPC) is used as an antiseptic in the processing of wood-based waste. This substance is less volatile and less toxic than sodium pentachlorophenolate. HTPC is chemically resistant, does not burn, it is well soluble in water, has the ability to penetrate into the deeper layers of wood, has a high fungicidal activity at low concentrations of 0.005-0.05 wt.h.

The disadvantages of this invention include:

- the use of a mixture of a high content of Portland cement;

- the use of sodium pentachlorophenolate, although not toxic, but unhealthy.

Known arbolite mixture according to Russian patent No. 2139838, MKI ⁶ SO4B 28/02, 1998, intended for the production of lightweight concrete used in industrial, agricultural and civil engineering. This arbolite mixture includes a binder consisting of Portland cement and additives, wood aggregate, calcium chloride and water. As an additive, the binder contains sand in an amount of 11-24 wt.% And has a specific surface area of 4500-5000 cm ² / g, while the components of the mixture are taken in the ratio, wt.%:

Portland cement 30.7-35.0 Sand 4.4-9.7 Wood aggregate 31.8-34.0 Calcium chloride 4.2-5.7 Water 22.5-24.0

In addition, in the arbolite mixture, sand may contain feldspar and quartz in a ratio of 0.9-1.1.

The use of finely ground sand as a binder additive is due to the fact that it has low water demand, increases workability and water resistance of the concrete mixture, and helps to reduce the consumption of Portland cement. The introduction of sand into the binder in an amount of less than 11 wt.% Is technologically impractical, and its content of more than 24 wt.% Leads to a decrease in the compressive strength of the mixture. When the ratio in the sand of feldspar and quartz is 0.9-1.1, the grindability of the binder components improves, which leads to its more stable particle size distribution and helps to increase strength in the initial stages of hardening of the mixture. When the ratio of feldspar and quartz is less than 0.9 and more than 1.1, an additional increase in the strength of the mixture does not occur.

When the specific surface area of the binder is less than 4500 cm ² / g, the conditions of its hydration worsen, and grinding to a specific surface of more than 5000 cm ² / g is impractical.

The disadvantages of this patent include significant energy consumption for grinding sand to obtain it with a specific surface area of 4500-5000 cm ² / g

A known composition for the manufacture of heat-insulating material according to the patent of Russia No. 2053972, MKI ⁶ SO4B 28/08, 07/10/1992, used in the production of building materials for building structures as a fireproof insulation layer. This composition for the manufacture of heat-insulating material includes crumbling slag for the production of low-carbon ferrochrome, dry gas cleaning dust for the production of silicon or silicon alloys, sodium hydroxide as the alkaline component in the following ratio of dry mix components, wt.%:

Crumbling slag production of low carbon ferrochrome 5-15 Dust dry gas purification silicon production or silicon alloys 69-81 Sodium hydroxide 14-23 With a water-solid ratio within 0.25-0.5

The manufacture of thermal insulation products from the proposed composition is as follows. Sodium hydroxide is charged into the mixer, then dust from dry gas purifiers from silicon or silicon alloys, crushed crumbling slag from the production of low-carbon ferrochrome and water are added. All these components are mixed for 30 minutes, as a result of which the temperature of the mixture rises to 55-65 ° C due to the exothermic reaction, then it is cooled to + 40-45 ° C. The composition is discharged into molds through a volumetric metering hopper. The collected package of forms is dried at 310-380 ° C.

With all the advantages of this raw material mixture, it has the main disadvantages:

- a relatively high density of thermal insulation material (product) ~ 800 kg / m ³ ;

- high thermal conductivity with coefficient. W / mK ~ 0.470.

The closest in its technical essence to the composition of the raw materials and the achieved result to the proposed technical solution is “Raw mix for the manufacture of wood-concrete materials” (in various combinations). An approximate composition of the raw material is presented in the following ratios of components, wt.%:

Mineral binder (Portland cement) thirty Wood aggregate 40 Mineral aggregate (expanded vermiculite) 10 Liquid glass 0.6 Water rest

See Buzhevich G.A. “Lightweight Concrete on Porous Aggregates,” Moscow, Publishing House of Construction Literature, 1970

Cement of any brand is used as a mineral binder, in order to save it, ground lime is added, which in addition serves as an antiseptic for wood aggregate.

As a wood filler according to the patent can be used: sawdust, shavings, crushed, it may contain waste from the production of wood concrete, wood concrete, wood-cement boards, etc.

Exfoliated vermiculite may be used as a mineral aggregate.

The technology for obtaining the raw mix for the manufacture of wood-concrete materials is as follows: wood aggregate and mineral binder are loaded into the concrete mixer and mixed dry until smooth for 1-1.5 minutes, then water is added 3/4 of the calculated amount and liquid glass, all mixed for another 1-1.5 minutes. At the same time, the mineral binder - cement, as a more active substance, hydrates water, forming a cement gel that sticks to wood particles, and liquid glass, dissolving in part of the water, forms a film that envelops the particles of wood aggregate with particles of cement gel and forms a closed capsule in which the setting process of cement is stabilized with a slight fluctuation in the moisture content of the wood aggregate. Next, the mineral aggregate (vermiculite) is loaded and the rest of the water and mixing are 1-2 minutes. In this case, the particles of the mineral aggregate, without violating the existing structure of the capsule of the wood aggregate, covered with cement gel and enclosed in a film with liquid glass, are evenly distributed between the particles and moistened by the added water. After the particles of the mineral aggregate are saturated with water, they will adhere to the capsule particles of wood aggregate and cement gel under the action of somatic forces. The entire mixing process takes place continuously for 3-5 minutes. In this case, a homogeneous friable mass of the raw material mixture is obtained.

A variety of wood-concrete products-blocks, panels, slabs, timber of various sizes and configurations can be prepared from the obtained raw material mixture in one of the following ways: by vibrating with a load, pressing at a temperature of 15-20 ° C, vertically directed vibration, pneumatic and mechanical thrombosis followed by drying and hardening.

With all the advantages of the known raw material mixture, it has the main drawback, namely its high cost due to the significant content of mineral binder - cement in its composition. In addition, products from this raw material mixture have a relatively high density.

The objective of the proposed technical solution is to increase the technical and economic indicators of the production of heat-insulating lightweight concrete.

The technical result of the invention is the involvement in the production of heat-insulating lightweight concrete inexpensive mineral aggregates, including waste from the production of silicon.

The technical result is achieved in that the raw material mixture for the production of heat-insulating lightweight concrete, including mineral binder - Portland cement, wood aggregate, mineral aggregate - expanded vermiculite, water glass and water, contains wood fiber material and additional gas cleaning dust from the electrothermal production of silicon as a wood filler and / or ferrosilicon in the following ratios of components, wt.%:

Mineral cement - Portland cement 2-7 Wood fiber aggregate 2-7 Specified gas cleaning dust 29-40 Exfoliated Vermiculite 2-8 Liquid glass 11-20 Water 26-46

In addition, wood wool can be used as wood fiber material.

The chemical composition of the dust of gas purification of cyclones, wt.%: SiO ₂ 57-60; SiC 15-17; Cd 16-20; F ₂ O ₃ 0.75-1; Al ₂ O ₃ 0.9-1; CaO 1.2-1.92; Na ₂ O 0.2-0.7; MgO 0.4-0.9; other 0.1-0.2. Granular composition: 97% of particles, particle size less than 100 microns. The chemical composition of the dust of electrostatic precipitators, wt.% Loss on ignition - 4.57, SiO ₂ - 88.72, Al ₂ O ₃ - 0.58, Fe ₂ O ₃ - 0.90, CaO - 1.37, MgO - 1 , 40, SO ₃ - 0.48, Na ₂ O - 0.20, K ₂ O - 1.80. Gran composition: 95% of particles with a particle size of less than 1000 microns.

The chemical composition of dust from electrostatic precipitators produced by Fe-Si in wt.%: SiO ₂ - 91.5, SO ₃ - 1/39; CaO - 1.28; Al ₂ O ₃ - 0.745; Fe ₂ O ₃ - 1.459; K ₂ O - 0.399; MgO - 0.325; C - 2.45; with traces of P ₂ O ₅ - 910 ppm; Na ₂ O - 660 ppm; V ₂ O ₅ - 300 ppm; MnO - 290 ppm; TiO ₂ - 200 ppm; Cl - 89 ppm; ZnO - 81 ppm; CuO - 57 ppm.

Having a high specific surface area, these gas purification dusts, upon contacting with a dilute aqueous solution of liquid glass (a concentrated solution of sodium silicate with a siliceous module is from 1.5 to 3.5), acquires astringent properties. This is because an alkaline component, sodium hydroxide, is present in the diluted solution of water glass. In the interaction of active silica SiO ₂ with sodium hydroxide, a gradual thickening of the mixture takes place due to polycondensation and coagulation processes that take place in the solution of sodium hydrosilicates formed.

Thus, the gas treatment dust used in the raw material mixture of silicon production and / or ferrosilicon acts not only as a mineral aggregate, but also as an additional mineral binder at the same time. The use of expanded vermiculite with a low density as a whole allows it to be used as a filler for the production of heat-insulating lightweight concrete.

The use of wood aggregate in the form of fibrous materials: shavings, wood wool, wood wool, etc., allows to obtain reinforced lightweight concrete.

Common features of this proposal and the prototype are the following: the presence of a mineral binder - Portland cement, a mineral aggregate - expanded vermiculite, wood aggregate, water glass (aqueous solution of sodium silicate), water.

The differences are:

- the fact that one of the components of the mineral aggregate is gas cleaning dust of the electrothermal production of silicon and / or ferrosilicon (dust of electrostatic precipitators and dust of cyclones);

- the fact that wood fiber material is used as a wood filler;

- in the content in the raw mix of all components in wt.%.

This is the conformity of the technical solution to the criteria of the invention - "novelty."

Comparison of the proposed technical solution, not only with the prototype, but also with other solutions in this area known from patent and scientific and technical information, shows that:

- known are claimed in the claims separately taken components that are used in various compositions (combinations) and in various ratios by wt.% in raw mixtures for the production of heat-insulating materials (see above for a review of patents - analogues and prototypes for this application).

At the same time, the new proposed raw material composition for the production of heat-insulating lightweight concrete with a new composition and a new percentage allows you to:

- use in significant quantities waste from the electrothermal production of silicon and / or ferrosilicon (gas cleaning dust: dust from electrostatic precipitators and dust from cyclones);

- involve wood fiber material in the production;

- increase the strength of heat-insulating lightweight concrete.

The combination of features in the proposed technical solution, both known and unknown (distinctive), stated in the formula of the invention according to the composition and content of the components, allows (as shown by pilot tests):

- reduce the content of mineral binder - Portland cement to 2-7 wt.%;

- reduce thermal conductivity to 0.10 W / m ² · ° C;

- reduce bulk density to 663-670 kg / m ³ ;

- reduce the cost of production of heat-insulating concrete by 5-6% compared with well-known concrete of similar purpose;

- reduce transportation costs.

Thus, the proposed technical solution allows to achieve a technical and economic result of a higher level in comparison with the prototype.

Based on the foregoing, we can conclude that the technical solution meets the criteria of the invention - "inventive step".

The industrial applicability of the raw material mixture has been proven in the process of construction work (the Federal Service for Supervision of Consumer Rights Protection and Human Well-being has given a positive conclusion. Sanitary and epidemiological conclusion No. 38IC 066.576. T000627.07.07 dated 07.30.2007).

The content limits of the components in the proposed raw material mixture are determined empirically. The data are given in the table.

When the content of Portland cement in the raw material is less than 2%, the moisture resistance of the material decreases and the solidification time increases, with an increase in the content of more than 7%, concrete sets quickly, which complicates the spill process, increases the consumption of cement, and at the same time the cost of the material.

When the content of liquid glass is less than 11%, the strength of concrete decreases, with an increase of more than 20%, the strength does not increase, but the cost of the material increases.

When the content of vermiculite is less than 2%, the thermal insulation properties of concrete are reduced, when the content is more than 8%, the mechanical strength is reduced, and the consumption and, accordingly, the cost of the material are increased.

When the content of wood fiber material is less than 2%, the reinforcing properties of concrete are reduced, when the content is more than 7%, the reinforcing properties do not increase.

When the dust content of gas purification is less than 29%, the heat-insulating properties are reduced, when the content is more than 40%, the density of concrete increases.

With a water content of less than 26%, difficulties arise in obtaining a homogeneous mass of raw materials during the mixing process, with a content of more than 46%, the concrete hardening time increases.

The preparation of the raw mix for the production of heat-insulating lightweight concrete is as follows. Cement milk is prepared from water and cement based on a weight ratio of 50% to 50%. The remaining water is poured into the mixer along with liquid glass. During continuous operation of the mixer, gas cleaning dust from the electrothermal production of silicon and / or ferrosilicon, vermiculite and wood fibrous materials are loaded into it. Upon receipt of a homogeneous mass in the mixer, cement milk is poured into it. The mixing process is carried out until the final obtaining of a homogeneous viscous mass.

Claims (2)

1. The raw material mixture for the production of heat-insulating lightweight concrete, including mineral binder - Portland cement, wood aggregate, mineral aggregate - expanded vermiculite, water glass and water, characterized in that it contains wood fiber material and additional gas cleaning dust of electrothermal silicon production and / or ferrosilicon in the following ratio of components, wt.%:
Portland cement 2-7 wood fiber material 2-7 specified gas cleaning dust 29-40 expanded vermiculite 2-8 liquid glass 11-20 water 26-46 2. The raw material mixture according to claim 1, characterized in that it contains wood wool as a wood fibrous material.