Abstract: A method for treatment of metallurgical wastes i.e. slags, which are in liquid form by introducing water into the liquid slag thus causing it to cool at a slow rate so that the solidified slag contains a porous crystalline or utrified strucutre according to the rate of cooling, which structure is stable at ambient temperature. Another object of the invention concerns an apparatus for treating solid metallurgical slags, comprising a continuous conveyor formed of moulds and means adapted to diffuse water into the liquid slag.

Abstract: A multiple stage process for obtaining Ni units from Ni laterite ores and sulfur-bearing Ni concentrates during production of nickel-alloyed iron, nickel-alloyed steel or nickel-alloyed stainless steel in a reactor equipped with top- and bottom-blowing means. Dried Ni laterite ore is charged into an iron/slag bath mixture containing dissolved carbon and a metalloid reductant such as aluminum or silicon. The laterite ore is melted while heat is generated by oxidation of the metalloid and carbon in the reactor. After the laterite ore is melted, top-blowing of pure oxygen and bottom-blowing of an oxygen-containing gas are ceased. Bottom injection of an inert stirring gas is begun. A sulfur-bearing Ni concentrate and aluminum are added to the bath.

Abstract: In secondary steel refining, in addition to the process gas oxygen, the gases nitrogen and argon are employed as treatment gases in the bottom blowing converter. Oxygen and argon can be partially replaced by inexpensive CO.sub.2. The invention provides a process which makes it possible to completely replace nitrogen and argon by CO.sub.2.