Abstract: The method includes the steps of: adding a carbonaceous material B and a binder C, and optionally water, to electric furnace dust A generated in a steelmaking electric furnace 1, to form a powdery mixture D having a water content of 0.5 to 3 mass %; compacting the powdery mixture D into a raw briquette E; and charging the raw briquette without drying into a rotary hearth furnace 5 and thermally reducing the raw briquette to obtain a reduced iron briquette F and a crude zinc oxide G.

Abstract: It is an object of the present invention to provide a method of compacting a powdery mixture of electric furnace dust and a carbonaceous material into a briquette and subjecting the briquette to a thermal reduction treatment in a rotary hearth furnace, the method being capable of ensuring a strength of the briquette resistant to a handling in a course after the compacting through until it is set in the rotary hearth furnace, and reducing energy necessary for drying of the briquette while preventing bursting thereof in the rotary hearth furnace. The method comprises the steps of: adding a carbonaceous material B and a binder C, and optionally water, to electric furnace dust A generated in a steelmaking electric furnace 1, to form a powdery mixture D having a water content of 0.

Abstract: A method for making reduced iron using blast-furnace sludge is provided. The method includes a mixing step of mixing the blast-furnace sludge and an iron-oxide-containing powder to prepare a mixed material, an agglomerating step of agglomerating the mixed material to form agglomerates, a feeding step of feeding the agglomerates onto a continuously moving hearth, and a reducing step of heating the agglomerates to remove zinc and reduce the agglomerates.

Abstract: The present invention provides a method of purifying polluted soil and/or burned ash containing heavy metals and/or organic compounds with a higher throughput than a conventional method. In this method, polluted soil and/or burned ash is dried by, for example, a rotary dryer so that the moisture content is 5% by mass or less, preferably 3% by mass or less, and then large lumps having a particle diameter of 10 mm or more are removed by a vibrating screen. Only an undersize portion is formed into a briquette having a volume of about 6 cm3 by a press molding machine. The briquette is charged in a rotary hearth furnace together with the large lumps, and heated in the furnace to remove or detoxify the heavy metals and organic compounds by evaporation with high efficiency.

Abstract: A method for making reduced iron using blast-furnace sludge is provided. The method includes a mixing step of mixing the blast-furnace sludge and an iron-oxide-containing powder to prepare a mixed material, an agglomerating step of agglomerating the mixed material to form agglomerates, a feeding step of feeding the agglomerates onto a continuously moving hearth, and a reducing step of heating the agglomerates to remove zinc and reduce the agglomerates.