Physical simulation of refining process optimization for bottom argon blowing in a 250 t ladle

The influence of different permeable brick layout parameters,gas flowrate,feeding location and change in permeability of permeable bricks,on the refining effect was investigated by using water model experiment according to the prototype of a 250 t ladle with bottom argon blowing. It is shown that the mixing time of liquid steel with an arrangement of two permeable bricks at 0.75R(the position from the center of the ladle bottom to permeable bricks is 0.75 times the radius R of the ladle bottom) is shorter than that of permeable brick arrangements at 0.64 R and 0.5R,but this permeable brick arrangement results in a serious erosion of the ladle wall.Moreover,the mixing time of liquid steel with an arrangement of two permeable bricks at larger angles(135°,180°) is shorter than that at smaller angles(45°,90°). Thus the 0.64R-180° arrangement of two permeable bricks is the optimal solution. When material for liquid steel refining is added above permeable bricks or in the perpendicular bisector zone of the connection line of two permeable bricks,the mixing time of liquid steel is the shortest. The optimal bottom gas-blowing flowrate is 67 to 70 m₃·h^-1,which can meet the clean steel production requirement,i. e.,the mixing time of liquid steel is short,slag entrapment can be avoided,and the gas mixing energy can fully be used. The mixing time of liquid steel under the condition of permeable brick clogging prolongs and two bare bright circles with different sizes form in top liquid steel,which increases the erosion of the ladle wall refractory and reduce the mixing effect and cleanliness of liquid steel.