**1. Introduction**

The major tasks in the production of clean quality steel include the removing of inclusions and unwanted impurities, the secondary refining process is the important step of cleansing molten steel, and argon bottom blowing is one of the most popular ladle metallurgical methods in all types of ladle metallurgy processes as it is economical and easy [1]. During the argon bottom blowing, the molten steel homogenization and entrapment of the top slag have a great effect on the result of the ladle metallurgy. The water model [2–6] and mathematical models [7–9] are often used to simulate metal bath in the ladle during the argon bottom blowing, as the flow field in the ladle can be observed in the laboratory without the interfering of high temperature molten steel, splashing and dust in the actual teeming ladle. Some researchers found that eccentric bottom blowing is in favor of bath mixing in the ladle [7,10]. Some investigators also found that the position of porous plugs, gas flow rate and the size of ladle have an abundant influence on bath mixing in the ladle [4,5,11–17]. It was discovered that the top slag layer could consume some part of kinetic energy of flow and enlarge the mixing time of the ladle [18–22]. Some researchers studied the flow field and inclusion removal in the ladle during argon blowing by studying the bubble motion in the process of argon stirring [23,24]. The results of Luis E. Jardón-Pérez's research show that the ladle must be operated using a differentiated flow ratio for optimal performance [25]. With the help of the water model the argon bottom-blowing was improved dramatically. However, as the shortening of mixing time and decreasing top slag entrapment are a pair of contradictions during the argon bottom-blowing, the more reasonable and general compromise method should be studied based on the study of the detailed data of flow field in the metal bath of the ladle with the water model.

In this paper, based on the experiment of the water model, the bottom-blowing ladle of a Chinese steel mill was studied, and the effect of the layout of porous plug, argon flow rate and properties of top slag to ladle stirring efficiency, level fluctuation and slag entrapment. Based on the results, the operation of bottom-blowing of the ladle was improved.
