Cementless refractory castable. Part 9. HCBS and ceramic concretes in the Al2O3‒SiO2‒SiC system

The priority-chronological aspect of research and technological development in the field of SiC-containing HCBS and ceramic castables in the systems Al2O3‒SiO2‒SiC and Al2O3‒SiO2‒SiC‒C is characterized. The results of studies on the effect of the firing temperature and prolonged (up to 100 h) high-temperature heat treatment on the oxidation kinetics of SiC of different dispersion and content are considered. A noticeable oxidation, accompanied by an increase in the mass and growth of samples, is noted after 1200 °C and significant at 1300‒1400 °C. The effect of the firing temperature in the range of 1000‒1400 °C and long holding in a tunnel furnace (60 h at 1300‒1400 °C) on the dynamics of phase transformations and the structure of samples of the matrix system based on HCBS of composite composition (bauxite + 11 % VFQG), as well as with an additional content of 15% SiC. In contrast to firing in air, during the service of monolithic gutter masses in the Al2O3‒SiO2‒SiC‒C system, the working surface of concrete is largely isolated from the air due to cast iron and slag. This drastically reduces the rate of both SiC oxidation and carbon burnout. The zonal structure of the lining is characterized. The data on the effect of heating and cooling on the modulus of elasticity of ceramic castable are presented.

Device for differentiable cooling of products in a tunnel furnace

The design of a device for supplying differentiable flows cooling products with different enthalpy values has been developed. An algorithm has been developed to control the system for extracting hot air from the cooling zone at the junction of the cooling and firing zones for feeding into the mixing chamber with atmospheric air and then to the dryer. At the same time, part of the selected hot air enters a special sectional heat exchanger, where it is converted into two cooling flows with different enthalpies of heat agents. Ill. 2. Ref. 6.

BRICK FIRING PROCESS CONTROL SYSTEM

В статье приводится описание технологического процесса обжига керамического кирпича в туннельной печи. Приведено обоснование для внедрения автоматизированной системы управления туннельной печью и вариант структуры автоматизированной системы управления. The article describes the technological process of firing ceramic bricks of a tunnel kiln. The rationale for the introduction of an automated control system for a tunnel furnace and a variant of the structure of an automated control system are given.

Non-destructive tests of fibre-cement materials structure with the use of scanning electron microscope

The article presents the NDT results of research on the influence of high temperature on the destruction of the structure of fiber-cement board as a result of the failure of a tunnel furnace. Two fiber cement boards were tested. There was a plate in a tunnel furnace during a failure, and reference plate dried in normal conditions. The research used acoustic emission method in combination with artificial neural networks.Interesting research results were obtained, which allowed to observe visible changesin the structure of the tested panels under the influence of high temperature. An important application from the point of view of building practice was formulated.