The In-situ Formation Of Titanium Carbonitride From Ferrotitanium Slag And Its Effect On The Performance Of Taphole Clay

Taphole clay is an important refractory material to block the tap hole of blast furnace,and its stable performance has a great influence on the safety of blast furnace.TiCN is a solid solution formed by TiN and TiC,which has high melting point,high strength,good wear resistance and chemical stability.TiCN can improve the strength,oxidation resistance and slag resistance of refractories.Ferrotitanium slag is the waste residue produced by smelting ferrotitanium alloy and has a huge annual output.The main chemical components of ferrotitanium slag are Al₂O₃,Ca O and Ti O₂,which are like to the principal components of refractory materials.If ferrotitanium slag can be used in the field of refractories,great economic value can be created.Therefore,this paper first explored the feasibility a of TiCN with ferrotitanium slag as raw materials and calculated the reaction kinetics parameters;then pure TiCN was added into taphole clay to study the effect of TiCN on the physical properties,cold strength,oxidation resistance and slag resistance of taphole clay;Finally,ferrotitanium slag was added into taphole clay,and the effects of the amount of ferrotitanium slag on the physical properties,cold and hot strength,oxidation resistance and slag resistance of taphole clay were studied.Through the above research,relevant conclusions are drawn as follows:(1)The CaTiO₃in ferrotitanium slag can react with C,N₂or with C,Si₃N₄to form TiCN.The reduction process of CaTiO₃is CaTiO₃?Ti₃O₅?Ti O?TiC_0.2N_0.8,and the increase of C or Si₃N₄content and the increase of reaction temperature can develop the TiCN grains.(2)When TiCN was prepared with ferrotitanium slag and coke as raw materials,the reaction activation energy is 115.34 k J/mol,and the pre-exponential factor is 6.76×10⁴⁷min^-1,the most probable mechanism function of the reaction system is G(?)=[-ln(1-?)]3,the reaction mechanism is random nucleation and subsequent growth.When TiCN is prepared with ferrotitanium slag,coke and Si₃N₄,the reaction activation energy is 68.97k J/mol,and the pre-exponential factor is 8.72×10²⁸min^-1,the most probable mechanism function of the reaction system is G(?)=[(1-?)-1/3-1)]2,the reaction mechanism is three dimensional diffusion.(3)When pure TiCN was used as raw material,with the increase of the addition amount of TiCN,the oxidation resistance and slag resistance of taphole clay are improved obviously.TiCN was continuously distributed in the erosion interface to form a protective layer to prevent slag erosion;Moreover,TiCN was distributed in the erosion site of the slag,which increases the viscosity of the slag and prevents the penetration of the slag.(4)When ferrotitanium slag was used as raw material,anorthite and TiCN were generated in the taphole clay,thus the cold bending strength,hot bending strength,oxidation resistance,and slag resistance of taphole clay were improved.When 15 wt%3?1 mm,7 wt%1?0 mm and 2 wt%200 mesh ferrotitanium slag are used as raw materials,the physical properties,oxidation resistance and slag resistance of the taphole clay are all good.