A method and an apparatus for controlling a causticizing process, the process comprising slaking, causticizing and white liquor preparation. Preferably the buffer is a bifurcate buffer. , with standard commercial fruit growing practices, such as pruning, thinning, spraying, irrigation and fertilization. Alternatively, a combining gate may be included within the slice to combine the output of one slice with the output of another slice. Therefore, the thorium never reaches break-through and the column can be used continuously without regeneration. Particularly, the adhesive layer has a characteristic of expanding with the peeling-off liquid infused.