Patent ID: 7935174

Claim:
Procedure for the treatment of a material comprising sludge or muds from iron-and-steelworks comprising the following stages: receiving the material comprising sludge or muds, at a moisture range of 20 to 40% water; adjustment of the available CaO content in the material in order to obtain a level of available CaO of 3% to 8% with respect to the weight of the material; addition of a carbonaceous fuel by proportioning the carbonaceous fuel in accordance with a humidity of the material; introduction of the material on to one of the upper floors of a multiple hearth furnace; heating of the multiple hearth furnace; gradual transfer of the material to the lower floors; regulation of the temperature of the exhaust gas from the multiple hearth furnace to at least 500° C. and preferential formation of ferrites by combining the CaO with iron minimizing reduction of iron by regulating the temperature and holding time of treated material for a duration to ensure that the treated material is output from the furnace at a temperature within the range of 700° C. to 800° C., thereby causing the CaO to react with the iron oxides present in the material to form the ferrites of lime which favor agglomeration to achieve sufficient spontaneous granulation or pseudo-granulation of the material to render it transportable; and discharging the treated material as ferrites of iron exhibiting the granulation or pseudo-granulation.