Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Social and Environmental Engineering
Complete Melting of Steelmaking Slag and Behavior of Alkali Dissolution
Seitarou TauchiYoshiaki Kashiwaya
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2018 Volume 104 Issue 2 Pages 107-116

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Abstract

The problems on the alkali dissolution from steelmaking slag sometime occurred in the location of slag recycling. It is important to clarify the alkali dissolution mechanism and develop the method to inhibit an alkali dissolution. There might be many approaches for decreasing the alkali dissolution, the decrease of basicity (CaO/SiO2) is best and easy way for complete melting and inhibition of the alkali dissolution.

In this study, dephosphorization slag was modified by addition of reagent, fly ash (FA) and brown bottle (BB). Basicity was changed from 2.0 to 0.53. Dissolution experiments were carried out according to the condition developed by Kitamura, et al. based on JIS method.

Ca content in dissolution experiment, which analyzed by ICP, was highest compare to Al, Si, Mg, Fe and P. It was found that the relationship between the content of Ca dissolved and modified basicity (C/(S+F)=CaO/(SiO2+FeOx)) showed good correlation.

On the other hand, the pH value was excellent correlation with the content of Ca, although the value of pH saturated around 11 over 20 ppm of Ca. Then, using the relationship of ion product, Kw=[H+][OH], the equation between Ca and [OH-] was derived. Finally, the following equation successfully calculates the calcium content [Ca2+] ppm dissolved using pH value.

[Ca2+] = 3.0 × 10(pH–10)

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© 2018 The Iron and Steel Institute of Japan

This article is licensed under a Creative Commons [Attribution-NonCommercial-NoDerivatives 4.0 International] license.
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