Investigation of Liquidus Area and Fluidity of Oxides Affecting Stable Operation of Melting Furnace

Abstract

Since high social demands have been focused on detoxification as well as recycling of industrial wastes, the role of melting furnaces for wastes has been highlighted these days. However, due to scattering of compositions of components in industrial wastes, we are required to operate melting furnaces stably and to elucidate adequate operating conditions even for some compounds which are difficult to be melted under usual operations. In the present paper, we investigated 1) phase equilibria by thermodynamic databases, and 2) fluidity of molten slag for several compounds provided in melting furnaces. Then, we found that beneficial information was available on composition and temperature ranges of molten slag by thermodynamic investigation, which could provide useful guide to melt even asbestos and high-melting point compounds.

A Model for Estimating the Viscosity of Molten Aluminosilicate Containing Calcium Fluoride

“…To control the process operation we decided to use a specific property and monitored the change in its physical value during the operation. Miyabayashi et al 1) pointed out that the fluidity of molten slag can be a crucial operating factor. The fluidity of molten slag is generally evaluated by measuring its viscosity, but the estimation of viscosity by physical models is also considered useful because of the difficulty in measuring the viscosity of molten slags containing a wide variety of chemical compositions.…”

A Model for Estimating Viscosities of Aluminosilicate Melts Containing Alkali Oxides

“…Demand of smelting furnaces for waste treatment has been increasing in the respect of detoxification as well as recycling of industrial waste such as asbestos, 1,2) shredder residue, 1,3,4) and glass dust containing lead. 5) The essential issue in smelting furnace operations is to elucidate adequate conditions with the aim of stabilizing processes due to the wide variety in the composition of industrial waste.…”

“…5) The essential issue in smelting furnace operations is to elucidate adequate conditions with the aim of stabilizing processes due to the wide variety in the composition of industrial waste. In this regard, Miyabayashi et al 1) pointed out that the fluidity of slag is one of the crucial operating components. Although the fluidity of slag is typically evaluated by the viscosity measurement, the estimation of viscosity by models is considered to be much more helpful in evaluating viscosity in case of melting furnaces.…”

“…The system of the slag in melting furnaces for the waste including asbestos is the multi-component aluminosilicate containing CaO, FeO, Fe 2 O 3 , MgO, K 2 O, Na 2 O, etc. 1) Many models to estimate the viscosity of slag melts have been developed in the past. [6][7][8] It has been accepted that the estimation of viscosity of molten slags is a difficult task since the abrupt and complicated structure changes of silicate melts are reflected by the viscosity.…”