RU2163898C2 - Raw mix and method of manufacturing heat- insulating granular material - Google Patents

Abstract

FIELD: manufacture of heat-insulating materials. SUBSTANCE: raw components includes waste which results from processing black shales. Raw mix comprises, wt %: 59.06; SiO₂, 0.95; TiO₂, 16.55; Al₂O₃, 2.75; Fe₂O₃, 1.83; MgO, 3.15; K₂O, 2.57; Na₂O, 1.45; P₂O₅, 0.21; CO₂, 2.57; FeO, 4.61; MnO, 0.09; p.p.p., 5.20; C_org, 1.26 (55.2-56.2 wt %); microsilica resulting from crystalline silicon production (6.7-7.7 wt %) and liquid glass bond (37.1 wt %). Granules are molded from mix by plastic method and are fired using two-step mode, namely temperature rises up to 400 C at rate of 133 C/min, granules are kept at given temperature for 30 minutes, temperature rises up to 1175 C at rate of 5 C/min, and granules are kept at given temperature for 10 minutes. The resulting temperature has bulk density of 143-151 kg/cubic m. EFFECT: reduced average temperature and reduced firing temperature. 3 cl, 1 ex, 1 tbl

Description

 The invention relates to the production of building materials and products and can be used for the manufacture of heat-insulating material.

 Closest to the proposed production method is the manufacture of granular porous material from a raw material mixture, including carbonaceous shale, sealed with an aqueous solution of saponified tall lignin, taken in an amount of 0.5 - 1.5 wt.% From dry raw materials [1]. The disadvantages of this method are the relatively high average density and increased firing temperature of the material.

 The proposed solution ensures the achievement of a technical result - a decrease in the average density and firing temperature.

 The source of information [1] is the closest analogue of the invention in terms of raw mix and in part of the production method. The use of the invention contributes to the expansion of the raw material base for the production of heat-insulating products due to the use of waste from the processing of black shale (PPS). In terms of chemical composition, PSPS does not differ significantly from carbon-containing shales [1], but differs in particle size distribution (PSPS has a sieve residue of 008 10%). Unlike the breed itself, the waste from its processing has a finely dispersed state, which leads to an averaging of its chemical composition and an increase in the uniformity of the properties of both the raw material mixture and the resulting material. The use of PSPS as the main component of the raw material charge will allow not only to obtain high-quality heat-insulating material, excluding the stage of grinding of raw materials, which will reduce energy consumption in the manufacture of the final product, but will also contribute to solving the environmental problem.

The specified technical effect is achieved by the fact that as raw material components use PEFS with the addition of silica fume (MK) produced by crystalline silicon, closed by a liquid glass binder (FS), with the following ratio of components (wt.%): PPS - 55.2 ... 56, 2; MK - 6.7 ... 7.7; ZhS - 37.1. The granules are formed from the mixture and burned in a two-stage mode - raising the temperature to 400 ^o C at a speed of 133 ^o C / min, holding at this temperature for 30 minutes, raising the temperature to 1175 ^o C at a speed of 5 ^o C / min, holding at this temperature 10 minutes.

Black shales are the result of metamorphic sedimentary rocks with a high content of organic component (C _org -1.26%), and compose the thick strata with clearly marked foliation and composition heterogeneity. Waste arises from the fine grinding of black shale in ball mills by the Bodaibo mining and processing plant in order to extract finely dispersed ore mineralization [2].

The waste from the processing of black shale is a fine powder of dark gray color with the following chemical composition, wt.%:
SiO ₂ - 59.06
TiO ₂ - 0.95
Al ₂ O ₃ - 16.55
Fe ₂ O ₃ - 2.75
CaO - 1.83
MgO - 3.15
K ₂ O - 2.57
Na ₂ O - 1.45
P ₂ O ₅ - 0.21
CO ₂ - 2.57
FeO - 4.61
MnO - 0.09
pp - 5.20
C _org - 1.26
Silica fume produced by crystalline silicon is a dispersed waste characterized by a small particle size (0.1 ... 3 μm) and, as a result, a high specific surface area (more than 25 thousand cm ² / g). Silica fume is deposited in electrostatic precipitators of the gas treatment system of crystalline silicon production furnaces. The chemical composition of silica fume, wt.%:
SiO ₂ - 90 ... 95
Al ₂ O ₃ - Up to 0.8
Fe ₂ O ₃ - Up to 0.8
CaO - Up to 1.6
MgO - Up to 1.2
SiC - Up to 5
C _total - Up to 9
K ⁺ - Up to 0.25
Na ⁺ - Up to 0.06
p.p.p - Up to 20
Liquid glass with module 4 and a density of 1.44 g / cm ³ was obtained by technology according to the copyright certificate [3].

 The introduction of ZhS in the charge provides the formation of plastic dough from non-plastic dispersed components. The formation of the porous structure of the material during firing occurs due to the expansion of both the liquid fuels and PSV. In this case, the expansion of the liquid iron occurs due to the release of chemically bound water, and the expansion of the PSD - as a result of the decomposition and reduction of iron oxides during their interaction with organic impurities. The atmospheric highly active state of MC causes the early accumulation of the liquid phase. The finely dispersed raw materials and the associated increase in the chemical activity of the ingredients increase the swelling of the charge and reduce the average density of grains.

A smooth rise in temperature during the firing process and an additional exposure at 400 ^o C lead to a more complete burnout of organic impurities, which contributes to the saving of process fuel for firing and maximum expansion of the raw material mixture.

Example
The dispersed components of the mixture of PEFC and MK are mixed with FS in the ratios shown in table 1 (compositions 2, 3, 4). Granules are formed from the resulting mass. The pellets are fired according to a two-stage mode - raising the temperature to 400 ^o C at a speed of 133 ^o C / min, holding at this temperature for 30 minutes, raising the temperature to 1175 ^o C at a speed of 5 ^o C / min, holding at this temperature for 10 minutes.

Sources of information
1. Copyright certificate N 1825759 A1.

 2. Geostandarts Newsletter, volume XX, N 2, october 1996.

 3. RF patent N 2056353, MKI C 04 B 28/04, BI N 8, 1996

Claims (1)

1. The raw material mixture for the production of granular heat-insulating material, comprising a carbon-containing component and a binder, characterized in that as a carbon-containing component use waste from the processing of black shale when extracting fine ore mineralization with the following chemical composition, wt. %: SiO ₂ - 59.06; TiO ₂ - 0.95; Al ₂ O ₃ - 16.55; Fe ₂ O ₃ - 2.75; CaO - 1.83; MgO - 3.15; K ₂ O - 2.57; Na ₂ O - 1.45; P ₂ O ₅ - 0.21; CO ₂ 2.57; FeO 4.61; MnO 0.09; p.p.p. - 5.20; C _org - 1.26, and as a bundle, liquid glass and additionally introduce an addition of silica fume in the following ratio of components, wt.%:
Waste from processing black shale - 55.2 - 56.2
Silica fume - 6.7 - 7.7
Liquid glass - 37.1
2. A method of producing granular heat-insulating material, including the preparation of a mixture, molding and firing, characterized in that when preparing the raw material mixture according to claim 1, firing is carried out in a two-stage mode when the temperature rises to 400 ^o C at a speed of 133 ^o C / min, exposure at this temperature for 30 minutes, a further rise in temperature to 1175 ^o C at a speed of 5 ^o C / min and holding at this temperature for 10 minutes

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