RU2570175C1 - Raw mix for manufacturing of block foam glass and method of its manufacturing - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: raw mix for manufacturing of block heat resistant foam glass comprises the following components, wt %: crushed container glass 39.8-59.7; crushed medical glass 39.8-59.7; gasifier 0.5-0.8. The raw mix is heated to 825°C with delay of 30-40 minutes and subsequent slow reduction of temperature from 600° to 400°C with speed of 0.6°C/min. and quick reduction of temperature from 400° to 50°C with speed of 1.0°C/min.

EFFECT: increased heat resistance, reduced power inputs due to decreased annealing time.

2 cl, 3 tbl

Description

The invention relates to the field of producing heat-resistant block glass foam and can be used in nuclear engineering, building materials industry and as a heat-insulating material in heat engineering units, furnaces and other installations.

Foam glass compositions are known, including the use of glass block combat, container and sheet glass combat (Foam glass. Scientific fundamentals. 2008, p. 66, table 3.5). The disadvantage of this foam glass is its low heat resistance. Foam glass obtained from the battle of glass blocks, container and sheet glass is not heat resistant with its relatively high compressive strength, fire resistance, chemical resistance and low thermal conductivity.

Closest to the proposed composition of block heat-resistant foam glass is the composition of the raw material mixture containing ground cullet, blowing agent and quartz sand [RU 2411200 C1]. Foam glass obtained from a mixture of the proposed composition has a heat resistance of up to 350 ° C. The disadvantage of this raw material mixture is the use of ground quartz sand, which complicates the process due to additional operations for its preparation.

Currently, there are a number of methods for producing block foam glass. So, according to the patent RU 2187473 C2 (Suvorov S.A., Shevchik A.P., Mozhegonov A.S., Li Chi-Tai; from 07/12/2000) block foam glass is obtained by preliminary dispersion and hydroxylation of waste glass, averaging them with a foaming mixture (sodium liquid glass, active carbon black, sodium sulfate, active silica, boron oxide), granulation, filling the mixture into molds and compacting, sintering, foaming and quenching.

The disadvantage of this method is the high energy intensity and duration of the process, which leads to instability of the properties of block foam glass, low heat resistance.

A known method for producing block foam glass, comprising heating a pre-prepared and compacted in metal forms foaming mixture with exposure at a maximum temperature of 850 ° C for 1 hour, "sharp" cooling at a speed of 1, 65 ° C / min. - for 2 hours, and annealing for 4 hours 44 minutes with a speed in the temperature range of 600 ° -400 ° C (delayed cooling) and 400 ° -50 ° C (rapid cooling) equal to 0.11 ° C / min and 0.7 ° C / min. respectively (Foam glass. Scientific foundations and technology [Text]: monograph / NI Minko, OV Puchka, BC Immortal and others. - Voronezh: Scientific book, 2008. - P. 83, section 4.3.1, second paragraph; p. 84, fig. 4.2).

The disadvantage of this method is the high energy intensity and duration of the process, as well as low heat resistance of the final product, due to the fact that there is a stage of "sharp" cooling, characterized by high speed.

The objective of the proposed method is to improve the quality of block heat-resistant foam glass.

The technical result of the invention is to improve the quality of block foam glass by increasing its heat resistance.

The technical result is achieved in that the raw material mixture containing ground glass and a blowing agent, with the following content of components, wt. %:

glass container fight 39.8 ... 59.7 medical glass fight 39.8 ... 59.7 blowing agent 0.5 ... 0.8

Heats up to a temperature in the range of 825 ° C with an endurance of 30-40 minutes. This is followed by the stage of slow cooling with decreasing temperature from 600 ° to 400 ° C at a speed of 0.6 ° C / min and the stage of rapid cooling with decreasing temperature from 400 ° to 50 ° C with a speed of 1.0 ° C / min.

The proposed composition of the raw mix for block heat-resistant foam glass allows you to get foam glass with high values of heat resistance due to the content of the battle of medical glass. Medical glass contains components such as boric acid anhydride (B ₂ O ₃ ) and aluminum oxide (Al ₂ O ₃ ) in elevated concentrations, due to which it has a higher heat resistance, relative to the composition of sheet and tare glasses. The use of medical glass battle for the preparation of a raw material mixture allows components to be added to the composition of the foam glass to increase its heat resistance (B ₂ O ₃ , Al ₂ O ₃ ). Moreover, the components are in the necessary concentrations and conditions, which allows you to refuse additional operations for their preparation and introduction into the raw mix, greatly simplifying the production process of the finished product.

The proposed method for producing block heat-resistant foam glass is characterized by a reduction in the foaming time of the mixture at increased speeds in the slow and fast cooling stages, which contributes to microhardening of the final product, in which high values of foam glass strength are achieved, thereby increasing its heat resistance.

Characteristics of the components. To obtain foam glass use glass (glass break) of the following types:

- container glass, characterized by the following chemical composition, wt. %: SiO ₂ - 71.0 ... 72.5; Al ₂ O ₃ - 2.5 ... 4.0; CaO + MgO - 11.0 ... 13.0; Na ₂ O - 12.0 ... 14.0; SO ₃ - 0.3 ... 0.5;

- medical glass, characterized by the following chemical composition, wt. %: SiO ₂ - 74.0 ... 76.0; Al ₂ O ₃ - 5.0 ... 6.5; CaO + MgO - 1.0 ... 1.4; Na ₂ O - 4.5 ... 6.0; K ₂ O - 1.5 ... 3.0; In ₂ About ₃ - 6.4 ... 8.4; BaO - 4.0 ... 4.5.

In the composition of the raw material mixture for the manufacture of foam glass, coal was used as a gas blower, characterized by the following chemical compositions,%: ash - 4.3 ... 4.7; sulfur - 0.5 ... 0.8; volatile substances - 0.5 ... 1.5; carbon - 91.0 ... 93.0.

At the first stage, the optimal percentage of the battle of medical and medical glasses in the raw material mixture was determined experimentally based on the values of heat resistance of the obtained foam glass samples (table 1).

At the second stage, the optimal technological parameters of foaming were determined for the optimal composition of the raw material mixture (composition No. 4): temperature and time (table 2), based on the strength values of the obtained foam glass.

At the third stage, the values of the speeds were determined during slow and fast cooling (table 3).

Example

The initial components used were the battle of medical glass of the XT brand and the battle of container glass of the ZT-1 brand in a 1: 1 ratio of the following chemical compositions:

medical glass fight (HT-1 brand), wt. %: SiO ₂ - 74.0; Al ₂ O ₃ - 5.0; CaO + MgO - 1.2; Na ₂ O - 5.0; K ₂ O - 2.8; B ₂ O ₃ - 8.0; BaO - 4.0;

container glass battle (brand ZT-1), wt. %: SiO ₂ - 71.0; Al ₂ O ₃ - 3.5; CaO + MgO - 11.0; Na ₂ O - 14.0; SO ₃ - 0.5.

A foaming mixture was prepared by grinding in a ball mill with a volume of 100 l for 4 hours. At the same time, a gas generator (coal) of the following chemical composition was loaded into a ball mill at the same time as glass breaks of the ZT-1 and XT grades,%: ash - 4.7; sulfur - 0.8; volatile substances - 1.5; carbon is 92.0.

The finished mixture has the following composition wt. %:

ZT-1 brand container glass battle 49.6 XT medical glass fight 49.6 blowing agent (coal) 0.8

After grinding, metal molds of 300 × 300 × 300 mm in size made of stainless steel 1 mm thick were filled by one third with a mixture and compacted. Foaming of the samples was carried out in an electric muffle furnace with silicone heaters.

The temperature regime of the furnace with the previously determined optimal technological parameters is as follows:

temperature rise rate - 3.3 ° C / min

holding at 825 ° C for 35 min

sudden cooling to 600 ° C

annealing and microtreatment:

1) in the temperature range 600-400 ° C - 0.6 ° C / min

2) in the temperature range 400-50 ° C - 1.0 ° C / min

After cooling the muffle furnace, metal molds with block heat-resistant foam glass were removed from it. Then the foam glass was removed from the molds and subjected to mechanical processing. According to standard methods, foam glass samples were tested for strength and heat resistance, the results are shown in tables 1, 2, 3.

The tables show that with the claimed ratio of the components, the strength and heat resistance are at the required level. Reducing the amount of battle of medical glass leads to a decrease in thermal stability due to the insufficient content in the raw material mixture of components that increase heat resistance, namely B ₂ O ₃ and Al ₂ O ₃ . An increase in the content of battle of medical glass also leads to a decrease in the heat resistance of foam glass due to an increase in the amount of barium oxide (BaO), which at high contents reduces the heat resistance of glass and impairs the mechanical properties of foam glass.

It is possible to use foam glass obtained from a mixture of the proposed composition at temperatures up to 400 ° C, which is 50 ° C higher than that of the prototype.

Claims (2)

1. The raw material mixture for the manufacture of heat-resistant block glass foam, including ground glass and a blowing agent, characterized in that as the ground glass use the battle of medical and container glass, with the following content, wt. %:
glass container fight 39.8 ... 59.7 medical glass fight 39.8 ... 59.7 blowing agent 0.5 ... 0.8 2. A method of obtaining a block heat-resistant foam glass, including joint grinding of the charge components, compaction, heating, foaming, stabilization, slow and fast cooling, characterized in that the charge is heated to a temperature of 825 ° C with an endurance of 30-40 minutes and then a slow decrease in temperature from 600 ° to 400 ° C at a rate of 0.6 ° C / min and a rapid decrease in temperature from 400 ° to 50 ° C at a rate of 1.0 ° C / min.