STRUCTURAL ANALYSIS OF TITANIUM COMPOUNDS IN BLAST FURNACE HEARTH
Abstract
This article presents investigation of titanium carbonitrides which are generated in blast furnace hearth in purpose of its protection against prematurely erosion. Adding titanium into blast furnace burden is highly effective way of prolongation of blast furnace campaign and is used in steel mills worldwide. It is done by deposition of titanium nitrides, carbides and carbonitrides on blast furnace hearth walls. Once titanium materials are charged into declining burden and increasing temperature then starts composite chemical and physical processes. Titanium oxides are reduced into metal titanium which precipitate into pig iron and react with carbon and nitrogen and titanium carbonitrides are formed which ensure protection of hearth by forming protective layer on it.
Charging of titanium bearing materials is important part of blast furnace control process and is necessery to be monitored. The optimal way is adding exact sufficient amount of titanium to create protective layer. This is monitored by thermocouples placed in hearth refractory.
Structure analysis of protective layer during campaign of furnace is possible only by laboratory prepared samples. Therefore examination of sample taken directly from blast furnace hearth during general repairing is unique to analyse structures of titanium compounds and other present phases created in blast furnace conditions.
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