This study focuses on FGH4097 superalloy revert scrap. Based on a 2 t vacuum horizontal continuous casting facility， high-purity melting experiments were conducted with bottom-blowing argon. The entire process of argon bubble rising， crossing the melt pool interface， and bursting was recorded by high-temperature in-situ visual observation. By combining finite-difference numerical simulations of the heat conduction equation， the disturbance patterns of the temperature and viscosity fields caused by the bubbles and their influence on inclusion removal were systematically investigated. Experimental results show that melt temperature is the key factor governing bubble interfacial crossing behavior. In the range of 1 550 ℃–1 500 ℃， bubbles struggle to break through the top interface due to insufficient surface tension， leading to limited flotation purification efficiency. When the temperature drops below 1 500 ℃， a pronounced heat-affected zone forms around the bubbles， increasing the local melt viscosity， which enhances the adhesion and capture of fine inclusions. Bubbles can then stably carry inclusions across the interface and burst under vacuum， after which the inclusions are adsorbed by slag or crucible walls for removal. Numerical simulation results indicate that upon entering the melt， the bubble interior and its surrounding region maintain a significantly lower temperature than the bulk melt for several seconds， thereby forming a radial temperature gradient， with a corresponding localized increase in viscosity， which agrees well with experimental observations. The study reveals that inclusion removal by bubble flotation follows a triple coupling mechanism： thermal adhesion， interfacial adsorption， and mechanical entrapment. It clarifies the purification mechanism under the synergistic effect of temperature field， viscosity field， and bubble behavior. The findings provide a theoretical basis and process guidance for temperature range selection， argon blowing parameter optimization， and high-purity recycling of superalloy revert scrap in vacuum horizontal continuous casting.