Structure and coordination investigation of iron-ion tinting principle in ferreous glass

Abstract

The tinting phenomena of iron oxide contained glasses were studied from aspects of the electronic configuration, the iron ions coordination fields and the ions structure in glass. Several iron ion tinting forms at different redox or COD (chemical oxygen demand) conditions and their influential factors were given necessary explanations. The results reveal that the Fe³⁺−O−Fe²⁺ structure is the real tinting reason of iron involved glasses, whereas the Si⁴⁺−O−Fe³⁺ and Si⁴⁺−O−Fe²⁺ formulations modify the glass colours. Under oxidizing melting condition, the amount of 4/6-coordinated Fe³⁺ increases and makes the glass colour yellowish. Conversely, reducing melting condition makes the 6-coordinated Fe²⁺ increased and gives much blue tint to the glass. The conventional tank furnace melting the very strong reducing condition, which is of high COD glass batch, is not suitable. The high ratio of ferrous/ferric in glass can be obtained with a new refining technology which contains no or little amount of refining agent.

Keywords

ferreous glass / iron ions tinting / structure analysis / coordination theory / glass melting

References

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