RU2411201C2 - Ultrafine binding material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to construction materials, mainly to production of binding materials and can be particularly used in production of construction material. The ultrafine binding material is characterised by that it is obtained from a composition which contains the following, wt %: 8.33-31.91% aqueous solution of a hydroxide of an alkali metal 49.48-75.00, mineral material which contains amorphous silica - marl 25.00-50.52, where the weight ratio of the hydroxide of alkali metal in the aqueous solution is defined from the ratio to the weight of the amorphous silica in the range 1:(1-4). The hydroxide of the alkali metal used can be sodium hydroxide or potassium hydroxide. Sodium hydroxide obtained from a causticisation reaction of soda and slaked lime can be used.

EFFECT: high corrosion resistance of articles obtained using said binding material, strength properties and physical and mechanical properties of the binder, improved quality of the obtained material.

3 cl, 4 ex, 5 tbl

Description

The invention relates to construction materials, mainly to the manufacture of binders, and can be used in the production of liquid glass, unreinforced and reinforced chemically resistant products - stones, heat-resistant and refractory materials, heavy (including self-leveling), high-strength, waterproof and waterproof concrete, high-strength reactive powder (gravelless) disperse-reinforced concrete, general-purpose high-strength concrete using stone flour, mineral slag bet ones, geosynthetic cementless concretes, aerodrome and road coatings, cellular and light concrete, foam silicates and foamglass ceramics (including granular ones), foam glass, cellular and other ceramics, ceramic and silicate bricks, glue, paints, mastics and putties, as well as foundry production and in other areas.

Known astringent, including fly ash and alkaline component. As the alkaline component, sodium hydroxide or soda-alkali melt, or alkaline melt and additionally white soot are used in the following ratio of components, wt.%: Alkaline component 3-10, white soot 15-20, fly ash the rest (SU 1011594, 15.04 .1983).

The disadvantage of this method is the insufficient quality of the binder.

The closest analogue to the proposed invention is a high-strength cement binder mixture containing fly ash and an alkali metal, or a binder of alkaline earth metal silicate and an alkali metal, or a component of alkaline earth metal hydroxide, while the binder silicate has a SiO ₂ : M ₂ O weight ratio of approximately 0, 20: 1 to about 0.75: 1, the metal (M) being selected from the group consisting of Na, Li, K, 1 / 2Ca and l / 2Mg. The Na and alkali silicate component include an aqueous sodium silicate solution containing from about 38% to 55% solid sodium silicate, SiO ₂ : Na ₂ O ratio from 2: 1 to 3.22: 1, and from 45% to 62 % water based on the weight of an aqueous solution of sodium silicate, and the hydroxide component comprises from 25% to 100% sodium hydroxide and up to about 75% water based on the weight of the hydroxide component (US 5601643, 02/11/1997).

However, this mixture does not eliminate the above disadvantages.

The problem to which the proposed invention is directed, is to create such an ultrafine binder material that would eliminate the above disadvantages.

The technical result achieved by the implementation of this invention is to increase the corrosion resistance of products obtained using the declared binder material due to the use of marl as a mineral raw material, strength properties and physico-mechanical characteristics of the mineral binder, improving the quality of the obtained binder material, reducing energy intensity upon receipt.

The specified technical result is achieved in that the ultrafine binder material is characterized in that it is obtained from a composition including, wt.%: 8.33-31.91% aqueous solution of alkali metal hydroxide 49.48-75.00; the mineral raw material containing amorphous silica is marl 25.00-50.52, while the mass fraction of alkali metal hydroxide in the aqueous solution is determined from the ratio to the mass of amorphous silica in the range 1: (1-4). Moreover, caustic soda or potassium hydroxide is used as the alkali metal hydroxide, and caustic soda obtained from the causticization reaction of soda and slaked lime can be used as alkali metal hydroxide.

An ultrafine binder made from mineral raw materials contains alkali metal oxides, for example, sodium, with:

but. high thermal conductivity - intensify the processes of interaction of silica fume and alkali;

b. electrical conductivity - allow you to efficiently heat products (using a binder or based on it) when exposed to high-frequency alternating electromagnetic field (microwave);

from. fluidity - play the role of micro-fillers, helping to increase the mechanical strength of products using a binder.

Minerals and their oxides contained in an ultrafine binder made from mineral raw materials are highly dispersed (0.002–20 μm) and act as highly active fillers and catalysts for crystallization and / or polymerization (film formation) in products using a binder.

An ultrafine binder is prepared from mineral raw materials, if necessary, previously ground to 1.0 mm or up to 50 mm.

Mineral raw materials are dispersed in an aqueous solution of alkali metal hydroxide with concomitant disintegration by cyclic pumping of the mixture in a closed circuit in the cavitation mode at a temperature of 90-100 ° C. The preliminary introduction of solid alkali metal hydroxide into water leads to accelerated heating of the mixture due to the heat of reaction of the dissolution of solid alkali metal hydroxide and the formation of alkali metal hydrosilicates with the subsequent introduction of mineral raw materials.

In total, the active disintegration, mixing, and heating from the effect of cavitation and chemical reactions of the dissolution of solid alkali metal hydroxide and the formation of alkali metal hydrosilicates at atmospheric pressure takes no more than 5 minutes, which leads to the accelerated production of ultrafine binders.

The dispersion medium of the mixture in the form of 8.33-31.91% aqueous solution of alkali metal hydroxide is prepared by the reaction-cavitation method. On one mass part of an alkali metal hydroxide, 1-4 mass parts of marl are introduced, the disintegration and omulgation of which is carried out for 30-120 cycles to a particle size in the range of 0.002-20 microns.

Example 1

25 wt.% Marl contains 94 wt.% Amorphous silica SiO ₂ . Pre-crushed to 3.0 mm marl is dispersed in an aqueous solution of sodium hydroxide 75 wt.% With concomitant disintegration (with simultaneous grinding) by cyclic pumping of the mixture in a closed circuit in the cavitation mode at a temperature of 90 ° C.

The dispersion medium of the mixture in the form of 8.33% aqueous sodium hydroxide solution is prepared by the reaction-cavitation method, that is, the mixture is heated due to the chemical reaction and cavitation in the aggregate. 3.76 parts by weight of amorphous silica (1: 3.76) are introduced per mass part of sodium hydroxide, the disintegration and omulgation of which is carried out for 120 cycles to a particle size of 0.002-20 microns.

The composition for the preparation of binders includes:

Marl 25 wt.% NaOH 6.25 wt.% Water 68.75 wt.%

The cementitious material obtained by the reaction-cavitation method is an ultrafine aqueous solution of alkali metal silicates, which are in a homogenized state in a mixture (liquid - paste).

The density of the obtained binder is 1.3-2.2 g / cm ³ .

Further, ultrafine binder material is supplied in the required quantity for various industries or, if necessary, for cooling.

The specified composition of the bonding material from marl shows the best qualities for the production of non-autoclaved aerated concrete, since it has the highest and most stable amorphous silicon content among fossil mineral resources (on average 70-90%), it has the lowest content of undesirable impurities (clay organics).

In addition, in order to reduce the cost of production of ultrafine binders, the following formulation of marl, soda and lime was developed.

Soda and lime in an aqueous solution interact at ordinary temperature with the formation of alkali NaOH and calcium carbonate by the reaction:

Ca (OH) ₂ + Na ₂ CO ₃ = 2 NaOH + CaCO ₃

The caustification reaction proceeds quickly - for every 74 weight units of Ca (OH) ₂ and 106 weight units of soda, 80 weight units of alkali and 100 weight units of CaCO _{3 are formed} . Due to the fact that slaked lime has a high dispersion, the water content during production should be higher than that of the binding material on alkali.

So that the binder material on soda in finished form does not thicken due to the presence of molecularly dispersed calcium carbonate, the proportion of water should be further increased:

Grade II Lime 4.85 wt.% Soda 6.45 wt.% Marl 19.35 wt.% Water 69.35 wt.%

The soda ultrafine binder prepared by the reaction-cavitation method is the best in the manufacture of glue for building blocks and tiles, silicate, silicate-polymer, water-based paints, etc.

The potassium ultrafine binder prepared by the reaction-cavitation method is more resistant to coatings than sodium binder; therefore, it is preferable to use it in the manufacture of facade paints, roads, foundations, bridges, ceilings, pools and other products that are constantly in contact with water. It also increases the water resistance and frost resistance of concrete and cellular concrete.

Ultrafine cementitious material: sodium, soda, soda-sulfate or potassium, greatly accelerates the hardening of cements. The ultrafine binder is a colloidal solution of sodium and other (depending on the alkali used) silicates in water.

The chemical composition of ultrafine binders can be expressed by the formula:

Na ₂ O × nSiO ₂ + mH ₂ O + metal oxides

It can be seen from it that the ultrafine binder material does not have a constant composition and the ratio between the individual components can vary. The ratio of SiO ₂ : Na ₂ O = M, showing how much silicic acid is present per unit of sodium oxide, is called the silicate module of the binder. Its value usually ranges from 2.06. up to 3.5.

The amount of water can be very different. Depending on this, in the colloidal solution of soluble ultrafine binder material, its consistency - “density”, measured in degrees of the Baume scale or specific gravity readings, changes. The resulting binder with a density of 1.3-2.2 kg / l at the place of work, if necessary, is diluted with water to the desired concentration.

When adding soluble ultrafine binder material to the water going to mix cement, its setting time is greatly reduced (see Table 1). This is due to the fact that as a result of a chemical reaction between the alkaline silicate contained in the binder and the components of the cement clinker (calcium hydroaluminate), colloidal calcium hydrosilicate and sodium aluminate are formed according to the equation:

3Na ₂ O × SiO ₂ + 3СаО × Al ₂ O ₃ × nH ₂ O = 3CaSiO ₃ × nH ₂ O + 3Na ₂ O × Al ₂ O ₃

It is sodium aluminate formed in concrete that is a very strong accelerator of gaining strength.

In addition, another reaction takes place: between the "liquid glass" contained in the cementitious material and the lime in the cement to form calcium silicate:

Na ₂ O × 2SiO ₂ + CaO = Na ₂ O × SiO ₂ + CaSiO ₃

Calcium silicate is a very strong and dense material. A porous piece, such as quicklime, treated with an ultrafine cementitious material or its solution, becomes so dense and durable that it can be polished. Being deposited in the pores of a hardening stone, calcium silicate gives it increased density and water resistance.

This set of properties - accelerating the setting of concrete from the formation of sodium aluminate and reduced permeability of the pore space due to the clogging action of calcium silicate - determines the very wide use of ultrafine cementitious material as an additive for waterproof concrete for emergency operations: sealing leaks, caulking joints, waterproofing pools, etc.

The effect of additives of soluble ultrafine binder on the setting time of cement.

Table 1 Soluble binder additive in% by weight
cement Setting start (hour - min) The end of setting (hour - min) 0 1-40 5-05 one hundred 0-20 2-00 200 0-10 0-40

The main characteristics of ultrafine binders according to the Technical conditions:

table 2 Name of indicator The rate of ultrafine binder Appearance Homogeneous liquid or paste without mechanical impurities visible to the naked eye - cream, yellow, gray, graphite and brown Mass fraction of silicon dioxide,% not less 10 Mass fraction of alumina and iron oxide,% no more fifteen Mass fraction of calcium oxide,% no more 40 Mass fraction of sulfur oxide,% no more 0.3 Mass fraction of sodium oxide (potassium),%, not less 8 Silicate module, not less 1,69

The cementitious material prepared from the marl by the reaction-cavitation method is the basis for the accelerated (up to 6 times) production of non-autoclaved aerated concrete by “boosting” the kinetics of curing by chemical means.

In the manufacture of aerated concrete, ultrafine binders increase the need for mortar in water (see Table 4).

Table 3 Additive Water ml Spray on a shaking table, mm one No additives 225 153 2 Soda binder 175 144 3 Alkaline binders 125 154

The effect of ultrafine binders on mortar strength:

Table 4 Additive binder with a density of 1.4 g / cm ³ Water Cone spread, mm 1 day 3 days one No additives thirty 173 2,8 16,0 2 30 ml alkaline binder 10 150

3 30 ml of a mixture of binders (soda - 1 part + alkaline - 2 parts) 10 124

Example 2

Mergel (40 wt.%) Containing ultrafine amorphous silica (98.4 wt.%) Is dispersed in an aqueous solution of sodium hydroxide (60 wt.%) With concomitant disintegration by cyclic pumping of the mixture in a closed circuit in the cavitation mode at a temperature of 98 ° FROM.

The dispersion medium of the mixture is prepared by the reaction-cavitation method in the form of a 16.38% aqueous sodium hydroxide solution. For one mass part of sodium hydroxide, 4 mass parts of amorphous silica (1: 4) are introduced, the disintegration and omulsification of which is carried out for 90 cycles to a particle size of 0.002-10 microns. Ultrafine binder with the use of sodium hydroxide (caustic soda) in the finished form due to the presence of a solution of silicic acid, other minerals, metals and their oxides, as well as molecular dispersed carbon, which acts as nanodispersed reinforcement, significantly accelerates the set of strength and increases the strength of cement stone .

The use of ultrafine reinforcement leads to an increase in physical and mechanical properties, for example, cellular concrete (foam concrete, aerated concrete).

The composition of the binder on marl:

Mergel (A.S.W.) 40.00 wt.% NaOH 9.84 wt.% Water (H ₂ O) 49.16 wt.%

Example 3

Mergel (38.30 wt.%) Contains 40 wt.% Amorphous silica. Mergel is dispersed in an aqueous solution of sodium hydroxide (61.70 wt.%) With concomitant disintegration by cyclic pumping of the mixture in a closed circuit in the cavitation mode at a temperature of 96 ° C.

The dispersion medium of the mixture is prepared by the reaction-cavitation method in the form of a 17.24% aqueous solution of sodium hydroxide. For one mass part of sodium hydroxide, 1.44 mass parts of amorphous silica (1: 1.44) are introduced, the disintegration and omulsification of which is carried out for 30 cycles to a particle size of 0.002-20 microns.

The ultrafine binder material made from marl using sodium hydroxide (caustic soda), in the finished form due to the presence of a solution of silicic acid, ultrafine calcium carbonate and other minerals, metals and their oxides (aluminum oxide, etc.), is used as the basis for the production of ceramic and glass-ceramic (including cellular) products by firing.

The composition of the binder material from marl:

Mergel (A.S.W.) 38.30 wt.% NaOH 10.64 wt.% Water (N ₂ O) 51.06 wt.%

Example 4

Mergel (41.66 wt.%) Contains 20 wt.% Amorphous silica. Mergel is dispersed in an aqueous solution of sodium hydroxide (58.34 wt.%) With concomitant disintegration by cyclic pumping of the mixture in a closed circuit in the cavitation mode at a temperature of 90 ° C.

The dispersion medium of the mixture is prepared by the reaction-cavitation method in the form of a 14.28% aqueous solution of sodium hydroxide. One mass part of amorphous silica (1: 1) is introduced per mass part of sodium hydroxide, the disintegration and omulsification of which is carried out for 30 cycles to a particle size of 20 μm.

Ultrafine binder made from marl using sodium hydroxide (caustic soda), in the finished form due to the presence of a solution of silicic acid, ultrafine calcium carbonate and other minerals, metals and their oxides, will be used as a base or additive in the production of slag-alkali compositions and materials , ceramic and glass-ceramic products when exposed to high-frequency alternating magnetic field (microwave) and / or firing.

The composition of the binder material from marl:

Mergel (A.S.W.) 41.66 wt.% NaOH 8.34 wt.% Water (N ₂ O) 50.00 wt.%

The claimed binder material provides higher than the prototype, the corrosion resistance of products with its use is 20-30%. Examples of the composition of the ultrafine binder material from a particular type of mineral raw material are presented in Table 5.

Table 5 Examples of the claimed composition Name of components The content of components, wt.% one 2 3 four 5 6 Mineral raw materials 25.00 40.00 38.30 41.66 50.52 Alkali metal hydroxide 6.25 9.84 10.64 8.34 15.79 Water 68.75 49.16 51.06 50.00 33.69 Total: one hundred one hundred one hundred one hundred one hundred

Claims (3)

1. Ultrafine binder material, characterized in that it is obtained from a composition including, wt.%:
8.33-31.91% aqueous solution alkali metal hydroxide 49.48-75.00 mineral raw materials containing amorphous silica - marl 25.00-50.52,
the mass fraction of alkali metal hydroxide in the aqueous solution is determined from the ratio to the mass of amorphous silica in the range 1: (1-4). 2. The material according to claim 1, characterized in that sodium hydroxide or potassium hydroxide is used as alkali metal hydroxide. 3. The material according to claim 1, characterized in that caustic soda obtained from the causticization reaction of soda and slaked lime is used as an alkali metal hydroxide.