RU2172724C1 - Composition and method of manufacturing heat-insulation refractory material - Google Patents

Abstract

FIELD: refractory materials. SUBSTANCE: composition contains, wt %: liquid glass 13-35, silicon 4-11, calcium hydroxide 2-3, copper 0.03- 0.05, and refractory material - the balance. All components are jointly ground to give fraction 0.063-0.25 mm. Solid constituents are stirred with liquid glass, calcium hydroxide, and water to form homogeneous creamy paste. Paste is placed in molds, swelled, and hardened. Hardening is initiated by lowing air in amount 8-15 cu.m per 1 cu.m of material. According to invention, 0.03-0.05 wt % finely dispersed copper is used as catalyst. EFFECT: enhanced refractory characteristics and stabilized chemistry. 3 cl, 2 tbl

Description

 The invention relates to the industry of refractory materials, and in particular to compositions and methods for the manufacture of heat-insulating refractory products and heat-insulating refractory products. The invention relates to the production of heat-insulating refractory material by the chemical method. It can be used in ferrous and non-ferrous metallurgy, as well as in all industries using thermal units, in addition, in industrial and civil engineering.

 A known composition for the manufacture of heat-insulating material with the following ratio of components, wt.%: Water glass 32-52, sodium hydroxide 3-4, chamotte 25-36, ferrosilicon 20-28, which can be used as a binder in a ratio of 1/3 s various fillers (patent RU N 2060239, C 04 B 28/26, 1993).

 The disadvantage of this composition is the use of ferrosilicon as a reagent, which reduces the refractoriness of the insulating material due to an increase in the content of iron oxides in it.

 The closest analogue to the claimed composition is a composition for the manufacture of heat-insulating refractory material containing liquid glass, 1-34% of its mass is a refractory filler, as well as silicon and calcium oxide hydrate with the possible content of other additional components (patent GB N 1153299, C 04 B 19/04, 1969).

 A known method of manufacturing a heat-insulating material, which consists in dissolving the granules of sodium hydroxide in liquid glass with the further introduction of finely divided ferrosilicon and chamotte with stirring until a uniform plastic consistency is obtained. The resulting mass is filled in snap-in structure, in which it is expanded and cured (patent RU N 2060239, C 04 B 28/26, 1993).

 The disadvantage of this method is the lack of technological methods and means aimed at the completeness of the reactions of the chemical interaction of the reactants.

 The closest analogue to the claimed method is a method for producing a heat-insulating refractory material, comprising mixing components - water glass, silicon, calcium oxide hydrate and refractory filler with the possible content of other additional components, casting the mass into molds, expanding and curing it (patent GB N 1153299, C 04 B 19/04, 1969).

 The aim of the invention is to increase the refractoriness of the insulating refractory material and the stabilization of the chemical composition.

This goal is achieved in that the composition for the manufacture of heat-insulating refractory material, including water glass, silicon, calcium hydroxide and refractory filler, additionally contains copper in the following ratio, wt.%:
Liquid glass - 13-35
Silicon - 4-11
Calcium Oxide Hydrate - 2-3
Copper - 0.03-0.05
Refractory Filler - Else
The goal is also achieved by the fact that in the method of manufacturing a heat-insulating refractory material from a composition containing liquid glass, silicon, calcium oxide hydrate and a refractory filler, including mixing the components, casting the mass into molds, expanding it and curing, additionally use a catalyst - finely dispersed copper the amount of 0.03-0.05 wt.%, produce a joint grinding of all solid components to obtain a fraction of 0.063-0.25 mm, mix the solid components with liquid glass, calcium oxide hydrate I and water until a homogeneous creamy mass, and curing is carried out by forced air in an amount of 8-15 cubic meters. m per cubic meter m of material.

During the interaction of silicon with liquid glass - Si with Na ₂ SiO ₃ - and the filler, vapors and gases are released containing silane, methane, hydrogen and water vapors, which lead to swelling of the mixture. Hardening produces silicates. It is known that silicates form not only regular structures from individual SiO ₄ ions to linear chains, plates and three-dimensional SiO ₂ structures (as the silicon / oxygen ratios increase from 1/4 to 1/2), they also form a huge number of complex compounds in the result of ion substitution reactions. So Al ³⁺ often replaces Si ⁴⁺ (J. Campbell. Modern General Chemistry, vol. 2, Mir Publishing House, 1975, pp. 309-312).

However, this reduces the positive charge of the crystal, which can be compensated by the parallel incorporation of the M ^{2+ ion} (such as Na +, K +) into the octahedral voids of the silicate structure.

Similarly, the substitution of two Si ⁴⁺ for two Al ³⁺ can be balanced by the incorporation of the Mg ^{2+ ion} into the octahedral (or tetrahedral) voids of the silicate lattice. It is clear that endless variations of such compositions are possible, explaining the huge variety of stable silicates.

 Therefore, the concept of a binder and a filler in TOM, obtained by the claimed method, is purely arbitrary, since as a result of the chemical interaction of the filler, water glass, silicon and oxygen in the presence of copper, silicates are ultimately formed, linking the whole part that has not entered into a chemical reaction filler.

 Copper in the process of producing TOM is a catalyst accelerating the process of incorporation of filler metal ions into the voids of the silicate lattice, thereby contributing to the completeness of the formation of stable silicates. Calcium oxide hydrate, increasing the alkaline environment, accelerates the reaction of chemical interaction of silicon with liquid glass, and also reduces the viscosity of the composition.

 Refractory filler increases TOM refractoriness. Various refractory materials can be used as a refractory filler.

 The dispersion of materials 0,063-0,25 mm increases the active surface of the components and ensures the completeness of the reactions of formation of silicates, including solving the problem of obtaining TOM with a uniform composition.

 Hydrogen released as a result of the interaction of silicon with an alkaline medium, reducing metals in the oxides of the filler, inhibits the formation of silicates.

 The formation of silicates is completed by oxidative processes, which are intensified by the introduction of atmospheric oxygen into the TOM.

 The composition is prepared as follows. Finely dispersed copper, refractory filler (for example, chamotte) and silicon are subjected to joint grinding with simultaneous averaging of the composition of the components.

 After grinding, water glass, calcium oxide hydrate and water are added to the mixture until a homogeneous creamy mass is obtained.

The resulting mass fill the form by 25-30%. When swelling, the material completely fills the form. Swelling of the material is accompanied by gas evolution and self-heating of the mass to 100-120 ^o C.

 Hardening of the composition occurs under normal conditions and begins with an open surface after 1.5-2 hours. In this case, the lower layer remains loose.

 Hardening of TOM by volume is carried out by forced air supply to the loose part of TOM through holes drilled in it.

 After solidification of TOM throughout the entire volume, the holes are filled with the initial composition or a layer is formed from the composition of another refractoriness.

As a refractory filler, materials containing Al ₂ O ₃ , MgO, SiO ₂ , ZrO ₂ , Cr ₂ O ₃ and other refractory oxides and elements are used, depending on the required thermophysical properties of TOM.

 The properties of the heat-insulating material based on the proposed composition are shown in the examples given in table. 1. The indicators see table. 2.

When curing in TOM, air was supplied in an amount of 8-15 m ³ per m ^{3 of} TOM.

 The obtained properties of heat-insulating refractory materials showed that when the content of the refractory filler is less than 50%, the strength properties of the material sharply fall.

 When the content of the refractory filler is more than 86%, an increase in the volume of the material does not occur, while the coefficient of thermal conductivity does not meet the parameters of the heat-insulating material.

 The fire resistance of the TOM manufactured according to the invention (composition 3) is 10% higher compared to the prototype (composition 5) due to the presence of copper in the composition of the catalyst.

The supply of 8-15 m ^{3 of} air to the TOM of air per m ^{3 of} TOM reduces the curing time of the TOM in volume by 3-4 times. The hardening time of the material is 4-6 hours. Air consumption is determined empirically.

Claims (1)

1. The composition for the manufacture of heat-insulating refractory material, including water glass, silicon, calcium oxide hydrate and refractory filler, characterized in that it additionally contains copper in the following ratio of components, wt.%:
Liquid glass - 13 - 35
Silicon - 4 - 11
Calcium Oxide Hydrate - 2 - 3
Copper - 0.03 - 0.05
Refractory Filler - Else
2. A method of manufacturing a heat-insulating refractory material from a composition containing liquid glass, silicon, calcium oxide hydrate and a refractory filler, including mixing the components, casting the mass into molds, expanding it and curing, characterized in that it additionally uses a catalyst - finely dispersed copper in an amount of 0 , 03 - 0.05 wt.%, Produce a joint grinding of all solid components to obtain a fraction of 0.063 - 0.25 mm, mix the solid components with liquid glass, calcium hydroxide and water to obtain homogeneous creamy mass, and curing is carried out by forced air supply in the amount of 8 - 15 m ³ per 1 m ^{3 of} material.

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