RU2442758C1 - Bonding material - Google Patents

Abstract

FIELD: production of building materials.

SUBSTANCE: invention refers to production of building materials, in particular of mineral bonding substances and can be used in production of lime-slag bonding materials. The bonding material includes blastfurnace granulated slag, a grinding intensifier and calcined soda. As a grinding intensifier it contains dustlike waste of mechanical electrode treatment with the following component ratio, weight %: Blastfurnace granulated slag 92,72-94,90; Dustlike waste of mechanical electrode treatment 0,10-0,28; Synthetic calcined soda 5,00-7,00.

EFFECT: improvement of plasticization, strength and crack resistance.

1 dwg, 1 tbl

Description

The invention relates to the production of building materials, in particular mineral binders, and can be used in the production of slag alkali binders.

For example, slag-alkali cements are known, which are hydraulic binders obtained by fine grinding of granular slag together with a low-hygroscopic alkaline component or mixing of ground slag with solutions of alkali metal compounds (Slag-alkali concretes on fine-grained aggregates. Edited by V.D.Glukhovsky -. 1981, p. 49-50).

For the production of slag-alkali cement, mainly blast furnace and electrothermophosphoric slags are used that meet the requirements of GOST 3476-74, the fineness of grinding of which is characterized by a specific surface of at least 300 m ² / kg (3000 cm ² / g according to the PSX-2 device).

Alkaline components, which are an integral part of slag-alkali cements, are introduced in them in an amount of 5-15% of the mass of slag in terms of dry matter, including non-silicate salts of weak acids such as soda ash.

The disadvantage of such binders is the high energy consumption for fine grinding of metallurgical slag.

A known method of intensifying the grinding of cement clinker by adding two-water gypsum in the amount of 2.5-3% of the mass of clinker. The addition of gypsum improves the grinding process of the raw material mixture by reducing the sticking and aggregation of small fractions of cement (Handbook of cement production. Edited by II Kholin. - M., 1963, p. 346).

However, in the case of a cinder-alkaline binder, the addition of gypsum impairs its properties. Gypsum, reacting with an alkaline component, significantly reduces the setting time of the slag-alkali binder, which complicates the conditions for its use. In addition, as a result of the reaction of gypsum with an alkaline component, the alkali is neutralized, which leads to a decrease in the strength of slag-alkali binder and concrete based on it (Slag-alkali concrete on fine-grained aggregates. Edited by V.D. Glukhovsky. - Kiev, 1981, p. 115- 116).

Closest to the claimed technical solution is an astringent with the addition of 0.3-0.5% of coal, which is an intensifier of grinding the crushed material (article "Portland cement and its varieties" dated February 15, 2010, authors L. I. Dvorkin O. L. Dvorkin http://m350.ru/articles/more/v/id/85/).

The disadvantages of the known binder is that, introduced into its composition, the intensifier grinding does not provide an increase in the degree of plasticization of the resulting slag-alkali binder and its crack resistance.

The task of the invention is to intensify the grinding of blast furnace granulated slag to provide increased plasticization of the resulting slag-alkali binder, its strength and crack resistance.

The essence of the invention lies in the fact that the binder, including blast furnace granulated slag, grinding intensifier and soda ash, contains, as a grinding intensifier, a dusty waste of the machining of electrodes captured by the dust removal system, in the following ratio of components, wt.%:

Granulated blast furnace slag 92.72-94.90 Dusty waste machining electrodes 0.10-0.28 Synthetic Soda Ash 5.00-7.00

The technical result of the claimed invention is as follows: the introduction into the composition of the binder additive of pulverized waste by machining the electrodes in an amount of 0.1-0.3% by weight of slag allows for 9-17% to accelerate the grinding process of blast furnace granulated slag in comparison with the known addition of coal , respectively, to reduce energy intensity and increase the productivity of mills, which ensures cheaper production of slag-alkali binder. At the same time, the addition of the proposed grinding intensifier due to the plasticizing effect reduces the normal density of the dough from 26 to 22-23% and increases the compressive strength by 6-11% and the crack resistance of the slag-alkali binder by 27-41% at the age of 28 days of normal hardening.

Characteristics of raw materials

1. Granular slag.

For experimental verification of the inventive binder used blast furnace granular slag Mariupol Metallurgical Plant, characterized by the following data.

Chemical composition, %:

SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ total CaO MgO SO ₃ total TiO ₂ P ₂ O ₅ R ₂ O Cl ₂ RFP 38.10 6.38 0.72 40.92 5.86 0.41 0.18 0,025 1,61 <0.05 <0.05

According to the classification of GOST 3476-74, this slag with a quality factor K _k = 1.46, an activity modulus M _a = 0.18 and a basicity modulus M _o = 1.12 refers to the third grade. 2.

Alkaline component.

As a non-silicate alkaline component, synthetic soda ash was used, which meets the requirements of GOST 5100-85.

According to the classification of V.D. Glukhovsky, soda ash belongs to the second group of alkaline components of slag-alkali cements (Glukhovsky V.D., Pakhomov V.A. Slag-alkali cements and concrete. - Kiev, 1978, p. 28).

3. Slag grinding intensifier.

To intensify the grinding of granular slag, an additive of pulverized waste from the electrode production was used, which was captured by the dust cleaning system of the workshops for machining the electrodes of the Novocherkassk electrode plant. The specified pulverized waste of machining the electrodes is characterized by the following indicators: passes through a sieve with holes of 1.25 mm - 100% and 0.071 mm - 80-85%; the true density of the dust substance is 2.06-2.10 g / cm ³ ; the average bulk density of 0.65-0.82 g / cm ³ . Chemical composition wt.%: Carbon 96-98 (at least 95% of the carbon is represented by graphite); silicon carbide 1.5-2.0; oxides of silicon, iron and aluminum - the rest.

Example.

For experimental verification of the inventive binder, blast furnace granular slag of the Mariupol Metallurgical Plant was milled in a laboratory ball mill together with an intensifying grinding additive of pulverized waste from machining the electrodes to a specific surface of 3000 cm ² / g, determined on a PSX-2 device according to the generally accepted method.

The blast furnace granulated slag, crushed to the required specific surface, together with the grinding intensifier was closed with a solution of soda ash with a density of 1,050-1,071 g / cm ³ at a temperature of 20 ° C based on the dosage of soda for dry matter 5-7% (3.5-4% for Na ₂ O) from the mass of slag with the adjustment of the water flow to obtain a test of normal density, determined by the standard method.

Samples of cubes with a rib of 70 mm were formed from a test of normal density for strength tests at the age of 28 days of normal hardening and samples of a beam 40 × 40 × 160 for determining the crack resistance.

The strength characteristics of the crack resistance of a slag-alkali binder, the so-called fracture toughness under static loading, were determined on beam samples 40x40x160 mm in size, 28 days old, under conditions of nonequilibrium mechanical tests in accordance with GOST 29167-91. Such tests are characterized by a loss of stability of the sample deformation process at the time of deformation localization upon reaching the maximum load with the corresponding development of the main crack. For this purpose, beam samples of 40 × 40 × 160 mm in size with an initial notch depth of 10 mm and a width of 0.5 mm were produced, obtained by laying when forming samples of steel plates of appropriate sizes.

, который определяется по экспериментальным данным с использованием зависимости:The crack resistance characteristic in accordance with GOST 29167-91 is a conditional critical stress intensity factor

, which is determined by experimental data using the dependence:

- нагрузка, соответствующая динамическому началу движения магистральной трещины при неравновесных испытаниях, МН;Where

- the load corresponding to the dynamic onset of the main crack during nonequilibrium tests, MN;

L ₀ , b, t, a ₀ - the dimensions of the sample and the length of the initial cut (according to GOST 29167-91), m;

- относительная длина начального надреза (в нашем случае λ=0,25).

is the relative length of the initial notch (in our case, λ = 0.25).

The test results are shown in the table, from which it can be seen that the proposed binder, including an additive of 0.10-0.28% of pulverized waste from machining the electrodes as a grinding intensifier, is characterized by a reduction of 15-25% in the duration of slag grinding, in comparison with the prototype from 26 to 22-23% of the normal density of the dough, an increase in the age of 28 days of normal hardening of compressive strength by 6-11% and crack resistance of slag-alkali cement stone by 27-41%.

Physico-mechanical characteristics of the composition No. The composition of the binder, wt.% Duration of grinding to S _beats = 3000, cm ² / g · min The normal density of the test,% Compressive strength, MPa /%

/%Fracture toughness coefficient

/% blast furnace slag grinding intensifier soda ash Proposed 95 25 57.3 / 101 0.43 / 104 one 93.05 pulverized waste machining electrodes 6.00 0.05 2 94.90 0.10 5.00 85 23 60.2 / 106 0.52 / 127 3 93.80 0.20 6.00 75 22 63.1 / 111 0.58 / 141 four 92.72 0.28 7.00 80 23 61.9 / 109 0.55 / 135 5 92.00 0.50 7.50 85 23 61.3 / 108 0.54 / 132 Prototype one hundred 26 56.8 / 100 0.41 / 100 6 93.60 coal 6.00 0.40

Claims (1)

A binder, including blast furnace granulated slag, grinding intensifier and synthetic soda ash, characterized in that it contains pulverized waste from machining the electrodes as a grinding intensifier in the following ratio of components, wt.%:
Granulated blast furnace slag 92.72-94.90 Dusty waste machining electrodes 0.10-0.28 Synthetic Soda Ash 5.00-7.00