A numerical simulation was performed to study the flow pattern, mixing time and open-eye slag produced by argon gas injection in an industrial scale steel ladle under non-isothermal conditions. The liquid steel remains 5 min before the injection, and thermal stratification and convective flows were analyzed. Three different sequences in stages employing various argon-gas flow rates were simulated. In the first case, a sequence with the highest flow rates of argon was applied, while in the second and the third sequences, the intermediate and the lowest flow rates of argon gas were used, respectively. For determining the chemistry homogenization, the mixing time was computed and analyzed in all three cases. It was found that the cold steel is located near the walls while the steel with a high temperature is accumulated in the center of the ladle above the argon-gas tuyere. The higher and lower flows promote a faster chemistry homogenization owing to the secondary recirculations that are developed closer to the walls. The results from steel temperature drop show a good concordance with plant trial measurements.