Formation and sintering of vanadium carbonitride

Abstract

Vanadium carbonitride is commonly used in the steel making industry to improve the mechanical properties of steel. It is produced by the reduction reaction of vanadium trioxide (V2O3) or vanadium pentoxide (V2O5) with carbon in a nitrogen atmosphere. Vanadium carbonitride can successfully be produced in an induction heated shaft furnace.

Some briquettes have difficulty moving down the furnace during the industrial production of vanadium carbonitride in a shaft furnace. Solid plugs form in the furnaces from time to time and have a negative influence on furnace productivity.

In this study, the formation of vanadium carbonitride was investigated using a series of laboratory furnaces. In all the test work conducted, V2O3 and carbon were used as the basis for the starting material. The influence of factors such as temperature, retention time, pressure and feed material purity on the sintering, chemistry and agglomeration of laboratory produced pellets was determined.

It was found that, of the variables investigated, reaction temperature had the strongest single effect on the agglomeration of the pellets whereas retention time, load and insoluble impurities had an influence on the bonding strength between the agglomerated pellets.

It was concluded that during the production of vanadium carbonitride, a possible combination of factors leads to the formation of plugs in the shaft furnace. An optimal furnace operating temperature of 1200 °C with a retention time of 30 minutes was identified to reduce the occurrence of pellet agglomerations and plug formations.

Increased temperatures result in increased concentrations of vanadium and nitrogen and decreased concentrations of oxygen and carbon.