The Separation Behavior of Tib<sub>2</Sub> During Cl<sub>2</Sub>-free Degassing Treatment of 5083 Aluminum Melt

Abstract

Utilizing titanium diboride (TiB2) inoculation for grain-refining purposes is a widely established practice in aluminum casthouses and foundries. Since this inoculation is usually implemented jointly with or between routine melt treatment steps ahead of casting, it is important to know whether and how other melt treatment processes affect the fade of TiB2 particles. For the present study, we investigated the influence of degassing process on the separation behavior of TiB2 particles in aluminum melt. Multiple sampling methods were employed and the samples were analyzed via spectrometer analysis. The removal efficiency of TiB2 during the gas-purging process of 5083 aluminum melt was confirmed to be significant over 10 min of treatment time. The rate at which the TiB2 content decays was found to increase with the impeller rotary speed from 400 rounds per minute (rpm) to 700 rpm. The separation rate of TiB2 particles was obtained to be 0.05-0.08 min(-1) by fitting the experimental data. Particle mapping results suggest that the TiB2 particles were separated to a dross layer. The obtained experimental results were used to quantitatively evaluate the conventional deterministic flotation model. The deviation between the conventional model and the experimental data was explained through the entrainment-entrapment (EE) model. Suggestions were made for future analytical and experimental works which may validate the EE model.