Softeners of Complex Action for Mixtures on the Basis of Liquid Glasses

Processy litʹâ, 2019, Tom 135, №3, p.40-45

Abstract

Received 14.03.2019

UDK 621.742.22

The possibility of solving the problem of effective softening of mixtures on the basis of liquid glass through the use of complex softening modifiers. it is offered the modifying additive which in a complex solves the specified problem: has an acceptable minimum of residual durability, both in low-temperature (240–300 ⁰C), and in high-temperature area (750–800 ⁰C). The softening ability is achieved by the component composition of the modifier, which includes lignin-containing material, bentonite clay on a sodium base and vermiculite. The idea implemented in the work is based on the combination of the processes of destruction of the modifier components with the processes that form the maximum strength of the liquid glass during its polymorphism during the heating of the mixture. Thus, the maximum in the region of 300 0C corresponds to the thermal degradation of hydrolytic lignin, which thus performs the function of softening in this temperature range; the maximum in the region of 800 ⁰C corresponds to the metamorphism of inorganic components of the modifier – bentonite clay and vermiculite, providing a similar effect in the high-temperature region. The mechanism of their action is based on the combination of components ensuring the softening of the liquid-glass mixture both at low and high temperature intervals of the polymorphism of the liquid-glass composition. It was found that the important factor is not the type of alloy (cast iron or steel), and especially the thermally stressed state of the casting mold elements in the process of forming the casting, for example, for small and/or thin-walled rods completely washed by liquid iron melt, it is recommended that the component composition of the modifier corresponding to steel casting, more heat-resistant. According to the results of experimental studies, industrial testing of the results was carried out, on the example of casting production to the casting body – muldas. The practical application of the development allows to replace expensive and environmentally hazardous resin binders, in particular the technology based on furan process, with relatively low cost, but environmentally friendly liquid-glass binders.