Effect of the Dispersity of Glass Batch on the Structure and Properties of Foam Glass

Abstract

The effect of the dispersity of glass batch on the basic parameters of foam glass was investigated. It was found that foam glass with prescribed performance characteristics can be obtained by picking a definite combination of granulometric composition of the initial raw material and the temperature-time regime for foaming.Foam glass is a rigid high-porosity material with a closed cellular structure whose performance meets the highest specifications. The structural characteristics of foam glass combine different properties making it possible to use the glass as an absolutely incombustible, biologically and chemically resistant material that retains its properties at high temperatures and humidity [1].The properties of foam glass are regulated by using initial materials of different dispersity and changing the form and amount of foaming agent as well as by adjusting the technological parameters of the process: temperature, foaming time and firing regimes.The temperatures and times required for foaming of glass batch containing as the foaming agent different amounts of comminuted natural marble (microcalcite) were determined in [2]. It was shown that material with the prescribed density and water absorption can be obtained by varying the foaming time and temperature as well as the concentration of the foaming agent.It is known that the specific surface area S sp of the foaming mixture plays a definite role in the formation of foam glass. The effect of the particle size of the foaming agent on the kinetics of sintering and foaming as well as on the properties of foam glass is examined in [1]. The author showed that the larger S sp , the lower the sintering temperature is. Thus, if for powder with S sp = 60 cm 2 /g the sintering temperature is about 900°C, then the sintering temperature decreases to 750°C for powder with S sp = 930 cm 2 /g and 65°C for S sp = 3400 cm 2 /g. Theoretically, window glass ground to particle size corresponding to S sp = 6000 cm 2 /g can form foam even at 630°C. However, in reality its foaming temperature is higher, since below 700°C no foaming agent can form an adequate amount of gas.Powder made from window glass and passed through a 50 mm sieve was produced to determine the effect of the dispersity of glass batch on the main characteristics of foam glass under laboratory conditions. Material with smaller particles was obtained by additional comminution of the batch in a vibratory ball mill.A PIP 9.0 optical analyzer with measurement range 0.5 -3000 mm was used to study the particle size distribution of the powder obtained and to calculate the specific surface area of the particles. The samples prepared for the investigations in glycerin were placed on a glass slide and covered with a cover glass. In the course of the experiment the appearance of the particles is formed in the field of a transmitted beam of the microscope and converted into a digital signal by a video camera. The particle size distribution in the experimental sample is represented, by means of processing with a computer, in...