Method of expanding metallurgical slag

DETAILED DESCRIPTION We claim: 1.
In a method of expanding metallurgical molten slag wherein the molten slag is passed downwardly along a pre-expanding path and is contacted with a film of an expanding agent, and the pre-expended slag at the end of said path is further expanded, the improvement which comprises the steps of varying the position at which molten slag is delivered to said path in accordance with the temperature and viscosity thereof so that poorer-foaming slags at lower temperature traverse a longer pre-foaming path, maintaining a constant inclination of said path along its length, and varying lengths of paths for slags of different physical characteristics are varied so that the pre-foamed slag subjected to further expansion for all of the slags has essentially the same characteristics, the length of the path being varied by shifting an intermediate trough relative to a fixed upper trough and a fixed lower trough parallel to the lower trough, the upper trough dispensing a flow of molten slag and the intermediate trough underlying said upper trough and having a discharge edge shiftable along the lower trough.
2.
The improvement defined in claim 1, further comprising the step of subdividing the pre-expanding slag at the end of said path into at least two partial streams and uniting said streams for said further expansion.




Description:
FIELD OF THE INVENTION The present invention relates to a method of and to an apparatus for foaming or expansion of molten slags, especially blast furnace slags consisting of Thomas or Bessemer pig iron slags.
BACKGROUND OF THE INVENTION For the foaming or expansion of molten metallurgical slags, it has been considered necessary heretofore to contact the molten slag with a quantity of water such that the expansion takes place in the proper relationship between the molten slag and the water to obtain complete and uniform expansion of the slag.
To this end, various apparatus has been proposed heretofore.
For example, the slag may be expanded in foaming chutes or troughs in which the slag is passed continuously from one end of the chute to the opposite end thereof and is continuously contacted with a water film which is provided on the floor of the chute