A process for forming granulated slag includes collecting a molten slag flow directly from a blast furnace in a temperature range between 2500 F. and 2600 F., quenching the molten slag flow with a flowing spray of water while the molten slag flow is still in the temperature range between 2500 F. and 2600 F. to create a granulated slag flow such that ferrous materials and non-ferrous metallic materials solidify joined together in the granulated slag flow, drying the granulated slag flow, magnetically separating the solidified joined ferrous materials and non-ferrous metallic materials from the granulated slag with a magnet device, and size-screening the granulated slag flow.

A method for the treatment of black slag, which contains lime (CaO) or lime-based compounds, and which is generated in an electric furnace that produces steel from scrap, includes indirectly cooling the black slag immediately after the black slag exits from the electric furnace or after collection of the black slag in a cauldron, for a period of time between about 10 minutes and about 45 minutes.

An improved direct smelting system and process using a smelt reduction vessel (SRV), and optionally, a cyclone converter furnace (CCF). The improved system and process utilizes a fast quench system in which hot process offgas containing molten material is quench-cooled from greater than 1400? C. (2552? F.) to no more than 600? C. (1112? F.) in a time-of-flight of no greater than 1 second. The quenching occurs using water spray injection and vaporization to cool, stress and break solid slag into slag pieces small enough to remove from the quenching system. The improved system eliminates plant availability problems associated with (i) accretion formation in the offgas train as hot process offgas cools down in a conventional (slow) manner to allow for steam-raising for power generation or other heat recovery purposes, and (ii) trigger mechanisms causing slag foaming events in the SRV that propagate up the offgas train.

The present invention provides a method of simultaneously recycling plastics and detoxifying chromite ore processing residue with residual heat from a steel slag. By heating and gasifying plastics with steel slag, followed by catalytically split-decomposing the plastics with catalysts such as chromite ore processing residue, the plastics are thoroughly converted into a energy gas under water vapor gasification. The surface coking of Chromite Ore Processing Residue is avoided. Meanwhile, the energy gas reduces Cr.sup.6+ in Chromite Ore Processing Residue into Cr.sup.3+, and the energy gas is cooled, and CO.sub.2 and Cl in the energy gas are adsorbed by alkaline substances in Chromite Ore Processing Residue. With this method, chromite ore processing residue is detoxified, and steel slag is cooled, furthermore, energy is saved and a energy gas is obtained.

For a method for granulating molten material, in particular slags, in which the molten material is introduced into a granulating chamber in which water is held as a cooling liquid, wherein the molten material is preferably quenched and granulated with evaporation of the water, an acid is added to the water.

A nozzle, a tundish arrangement used for the production of granulated material, and a method and apparatus for the production of a granulated material with an improved size distribution are provided. The grain size and grain size distribution is controlled by a nozzle having a specific design. The nozzle comprises an upper inlet opening, sidewalls forming a channel, a bottom and at least one outlet opening or at least one row of outlet openings at the lower end of the channel. The outlet opening(s) in the channel have a size of at least 5 mm in the smallest dimension. A cross sectional area of the channel at the inlet A.sub.C is at least 3 times bigger than the total area of the outlet openings A.sub.T.

A process for producing substantially dry slag granules comprises adding a controlled amount of water to a molten stream of slag, and granulating the slag to produce solidified slag comprising substantially dry slag granules and slag wool. An apparatus for producing substantially dry slag granules comprises: (a) an inclined surface having an upper and lower ends for receiving and discharging the stream of slag; (b) a dispersion device at the lower end of the inclined surface for dispersion of the molten slag; (c) one or more water addition devices for adding a controlled amount of water to the molten slag; and (d) a collection area adjacent to the dispersion device for deposition of solidified slag produced by the dispersion. The quantity of slag wool produced by the process and apparatus is less than that which would be produced without the addition of water.

A method for producing hydrogen and/or other gases from steel plant wastes and waste heat is disclosed. The method comprises the steps of providing molten waste from steel plant like molten slag in a reactor. The molten slag is contacted with water and/or steam in the presence of a reducing agent to form a stream of hydrogen and/or other gases. The hydrogen and/or other gases can then be extracted from the stream of gases from the reactor.

A process for preparing a hydraulic binder, wherein a slag melt containing P.sub.2O.sub.5 and iron oxide and further containing CaO and SiO.sub.2 are subjected to a cooling step by adding an oxidizing agent for the iron oxide for granulating the slag melt to form amorphous slag glass.