Formation of Titanium Carbonitride from Hot Metal.

Abstract

Studies on the formation of TiC and Ti(C,N) from hot metal were preformed to determine the conditions required for the formation of a protective layer rich in titanium carbonitride on the refractories in the blast furnace hearth. In situ observations of the formation of TiC and Ti(C,N) from carbon-saturated iron containing 0.07 to 1.3 mass% titanium were made at 1 673 to 1 873 K using a confocal scanning laser microscope equipped with an infrared image furnace. In order to measure the activity coefficient of titanium, the solubility of titanium in carbon-saturated iron was measured and found to be 1.3, 1.0, and 0.3 mass% at temperatures of 1 798, 1 772, and 1 670 K, respectively. The activity coefficient of titanium in carbon-saturated iron is expressed as log f Ti ϭϪ5.41ϩ6 890/T. Based on the results the conditions for Ti(C,N) formation and the amount of TiO 2 addition to a blast furnace were calculated. At 1 773 K and 1.0 atm of nitrogen, the minimum titanium in hot metal to form Ti(C,N) was determined to be 0.2 mass%. Under typical blast furnace operation conditions, a titanium load of 3.6-5.2 kg TiO 2 /tHM is required. It was conclude that in situ observation using confocal scanning laser microscope provided us a unique and reliable technique to study thermodynamic of some molten metal systems.

Dissection Investigation of Ti(C,N) Behavior in Blast Furnace Hearth during Vanadium Titano-magnetite Smelting

“…For example, Bergsma and Fruehan et al 9) proposed a hypothesis on the formation mechanism of the Ti(C,N) protection layer, suggesting that the Ti(C,N) forms in hot metal. Li et al 10,11) confirmed the formation of Ti(C,N) in the molten iron liquid under different temperatures through confocal scanning laser microscope. Through…”

Advanced Process Modelling of Hot Metal Desulphurisation by Injection of Mg and CaO

“…Ti(C, N) originates from the addition of TiO 2 to the blast furnace. Li, Li and Fruehan 9) have studied the formation of Ti(C, N) from hot metal and have derived the accompanying thermodynamics. It follows that under average hot metal conditions Ti(C, N) is a stable phase whereas MnS is formed upon cooling of the sample and is not present in liquid hot metal as a separate phase.…”

Analysis of Blast Furnace Hearth Sidewall Erosion and Protective Layer Formation

“…A number of studies have investigated the hearth erosion of the BF, but the information on the composition and the microstructure of lumped skull lining material are still very limited. [7][8][9][10][11][12][13][14][15][16] An improved understanding of the skull formation and the wear…”