The present invention relates to a ladle block for use in a bottom of a molten metal ladle. The ladle block reduces the amount of contaminants, particularly slag, exiting the ladle during casting operations. The ladle block includes a floor defining an outlet and sidewalls substantially orthogonal to the floor. The floor and sidewalls define a channel having dimensions of length, width and height. Channel dimensions are determined from the Froude number, which is based at least partially on the casting flow rate.