RU2526034C2 - Method of producing foamed porous aggregates - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of granular heat-insulation materials from natural material - obsidian, pearlite and pitchstone. In the method of producing foamed porous aggregates by treating rock consisting of volcanic glass with an electromagnetic field, treatment is carried out using a field with wave number of 3400 cm^-1 and frequency of 103·10¹² Hz, which is resonant for structural water and OH groups in the glass structure. The method includes preliminary removal of mobile water by treating with an electromagnetic wave with wave number in the range of 3000-3200 cm^-1 and frequency in the range of (91-97)·10¹² Hz.

EFFECT: high volume of volcanic glass.

2 cl, 4 ex

Description

The proposal relates to the production of bulk thermal insulation materials from natural raw materials - obsidian, perlite and pechstein.

Perlite, obsidian and pechstein belong to the group of acidic volcanic glasses and differ in the water content in the texture. Perlite contains up to 8% water, obsidian - up to 1% and pechstein - 8-10%.

In the rocks, consisting of volcanic glass, there are 2 types of water:

- structural and mobile;

- water of hydroxyl groups (OH ^-1 ).

Moving water is in the pores, water molecules are connected by a strong hydrogen bond (absorption frequency in the IR spectrum is 3000-3200 cm ^-1 ). When heated, moving water causes cracking and glass breakage.

Structural water and OH ^-1 groups (the absorption frequency in the IR spectrum is 3400 cm ^-1 ) cause expansion (increase in volume) of volcanic glasses upon heating. [T.A. Ziborova. The state of water and hydroxyl in natural glasses according to IR spectroscopy. Perlite. Sat tr USSR Academy of Sciences geology of geophysics and geochemistry "Science", M., 1981 - p. 177; Kovalskaya F.I. Mineral raw materials. Perlite // Reference - M .: Geoinformmark CJSC, 1998].

Perlite expansion is carried out in shaft and rotary kilns. To improve the quality of expanded perlite, firing (depending on the composition of the raw material) is carried out in 2 stages (cyclic heating):

- preliminary firing at a temperature of 300-400 ° C in order to remove moving water;

- expansion by firing at a maximum temperature of 900-1200 ° C, depending on the composition and structure of the raw material.

High-frequency electromagnetic processing of dielectrics is used in industrial conditions in the production of plastics, ceramics, metal alloys, wood drying, etc.

The phenomenon of resonance is known when externally acting on an oscillatory system, which occurs when the vibration frequencies of the structure or its part (atoms, groups of atoms, molecules) and the external contour coincide. In resonance, the amplitude of the forced oscillations reaches a maximum, and it is possible to remove atoms or groups of atoms from the structure at reduced energy costs.

The aim of the invention is to increase the volume (expansion) of volcanic glasses (obsidian, perlite, pechstein) by processing them with an external electromagnetic field of the IR spectrum.

The goal - swelling of perlite and other rocks, consisting of volcanic glass, and the production of expanded perlite and materials based on it, is achieved by the fact that the wave number and vibration frequency of moving, structural water and groups are determined from the IR spectra of analysis of obsidian, perlite and pechstein OH ^-1 , and then using the generators of various systems, electromagnetic processing is performed by the field of the resonant frequency, which provides expansion.

As noted, the allocation of mobile water can cause cracking and destruction of raw materials, which leads to a decrease in product quality. Therefore, in the case when the raw material contains moving water, the processing is carried out in 2 stages.

1. Processing by an electromagnetic field with a wave number in the range of 3000-3200 cm ^-1 (frequency range - (91-97) · 10 ¹² Hz) in order to remove moving water.

2. Field treatment with a wave number of 3400 cm ^-1 (frequency 103 · 10 ¹² Hz) in order to impact structural water and OH ^-1 groups and expansion.

The chemical composition and structure of volcanic glasses can vary widely, in the case when the raw material does not contain moving water, processing is carried out in 1 stage - by a field with a wave number of 3400 cm ^-1 and with an oscillation frequency of 103 · 10 ¹² Hz.

Example 1. Under laboratory conditions, the polyfractional perlite deposit Arteni (Republic of Armenia) was expanded. The water content in perlite is 4.20%, the largest grain size is 2.5 mm. The processing was carried out in the emitter by an electromagnetic field with a wave number of 2500 cm ^-1 (frequency 75 · 10 ¹² Hz) without resonance. The processing time at constant inductor power was 47 seconds. The bulk density of expanded perlite is 180 kg / m ³ (grade 200).

Example 2. A sample of perlite according to claim 1. Processing in the emitter with an electromagnetic field of a resonant frequency with a wave number of 3400 cm ^-1 (frequency - 103 · 10 ¹² Hz). The processing time at constant inductor power was 32 seconds. Reduced energy consumption - 30%. The bulk density of expanded perlite is 160 kg / m ² (grade 200).

When firing perlite in an industrial environment, a lightweight aggregate of various grain composition is obtained:

1. perlite crushed stone of various fractions with a grain size of 5 to 40 mm;

2. perlite sand, consisting of grains less than 5 mm in size, which are also divided into fractions.

The use of fractionated lightweight aggregate allows to reduce the consumption of binder and the average density and thermal conductivity of products.

In example 2 of the initial application: a single-stage firing of perlite sand fraction less than 0.63 mm Under these conditions, when firing small fractions due to the release of mobile water, the grain composition changes, which slightly affects the average density and grade of expanded perlite, i.e. when swelling small fractions, one-step processing is possible.

With a single-stage processing of perlite gravel, a significant change in the grain composition is possible, which is undesirable, and in some cases unacceptable, in production conditions.

Example 3. For comparison, a one-stage firing of perlite crushed stone fraction 5-10 mm containing 4.20% water, including 0.75% structural and mobile water. Under these conditions, a one-stage treatment with an electromagnetic field with a frequency of 103 · 10 ¹² Hz led to a partial destruction of grains and a change in grain composition. The content of grains with a size of less than 5 mm after processing was 82% of the mass. Therefore, in the production of perlite crushed stone with a one-stage processing, the grain composition changes, which is associated with additional sieving costs, while the content of large fractions decreases by 60-80%, which leads to an increase in bulk density and its grade from 150 to 200.

Example 4. In a two-stage treatment with an electromagnetic field (frequency 95 · 10 ¹² Hz) in order to remove moving water and subsequent processing with a field with a frequency of 103 · 10 ¹² Hz to remove structural water and swelling, the number of destroyed grains did not exceed 3% of the mass, t. e. two-stage firing practically does not change the grain composition, bulk density and perlite grade.

Claims (2)

1. Method for the production of expanded porous aggregates by treating rocks consisting of volcanic glass with an electromagnetic field, characterized in that the treatment is carried out by a field with a wave number of 3400 cm ^-1 and a frequency of 103 · 10 ¹² Hz, resonant for structural water and OH groups in the structure of glass. 2. The method according to claim 1, characterized in that the moving water is first removed by treatment with an electromagnetic field with a wave number in the range of 3000-3200 cm ^-1 and a frequency in the range of (91-97) · 10 ¹² Hz.