A basic oxygen furnace slag treatment method includes the steps of mixing basic oxygen furnace slag with an active aqueous solution and then keeping the mixture thus obtained under an enclosed environment for reaction and then employing a solid-liquid separation procedure to separate solid phase from liquid phase. Since basic oxygen furnace slag has strong alkaline, the method of the invention overcomes the problem that directly discharging basic oxygen furnace slag will cause environmental pollutions. The basic oxygen furnace slag treatment method avoids a secondary pollution, and can turn waste into treasure, bringing a number of economic benefits.

A method of continuous manufacturing of solidified steelmaking slag including the steps of solidifying molten steelmaking slag comprising at least 2% in weight of free lime so as to produce solidified slag particles having a diameter below 1 mm, the molten steelmaking slag being put in contact with at least a first carbonation gas during such solidification, cooling the solidified slag particles down to a temperature below or equal to 300° C., in a closed chamber, the solidified slag particles being put in contact with at least one second carbonation gas during such cooling. The invention is also related to an associated device.

A method of continuous manufacturing of solidified steelmaking slag including the steps of solidifying molten steelmaking slag comprising at least 2% in weight of free lime so as to produce solidified slag particles having a diameter below 1 mm, the molten steelmaking slag being put in contact with at least a first carbonation gas during such solidification, cooling the solidified slag particles down to a temperature below or equal to 300° C., in a closed chamber, the solidified slag particles being put in contact with at least one second carbonation gas during such cooling. The invention is also related to an associated device.

Methods of recovering coal combustion products (CCPs) and/or dry bottom furnace slag (DBFS) from coal combustion byproducts are disclosed. The methods include compiling coal combustion byproducts (e.g., from combustion of lignite coal and/or bituminous coal), grinding the coal combustion byproducts to form ground coal combustion byproducts with a maximum particle size of 40 microns, and separating CCPs from the ground coal combustion byproducts using an electrostatic precipitator. The following CCPs can be separated from the coal combustion byproducts using the presently disclosed methods: fly ash, bottom ash (e.g., containing pyrites), scrubber materials (e.g., calcium sulfate and calcium sulfite), and raw coal.

Methods of recovering coal combustion products (CCPs) and/or dry bottom furnace slag (DBFS) from coal combustion byproducts are disclosed. The methods include compiling coal combustion byproducts (e.g., from combustion of lignite coal and/or bituminous coal), grinding the coal combustion byproducts to form ground coal combustion byproducts with a maximum particle size of 40 microns, and separating CCPs from the ground coal combustion byproducts using an electrostatic precipitator. The following CCPs can be separated from the coal combustion byproducts using the presently disclosed methods: fly ash, bottom ash (e.g., containing pyrites), scrubber materials (e.g., calcium sulfate and calcium sulfite), and raw coal.

Some methods for making a granular material comprise crushing demetallized slag particles with one or more crushers and screening the crushed demetallized slag particles with one or more screens to separate the demetallized slag particles into two or more fractions, the granular material comprising at least one of the fractions of the demetallized slag particles. Prior to the crushing, ones of the demetallized slag particles having a size that is less than or equal to 2 inches can account for at least 90% of the demetallized slag particles. An iron-compound content of the demetallized slag particles, by weight, can be less than or equal to 10%. Crushing and screening can be performed such that ones of the demetallized slag particles of the granular material having a size that is less than or equal to 1.25 mm account for at least 90% of the demetallized slag particles of the granular material.

Disclosed is a method of fabricating a construction element, the method comprising the manufacturing of a construction element including a slag, wherein the slag is comprising, on a dry basis and whereby the presence of a metal is expressed as the total of the metal present as elemental metal and the presence of the metal in an oxidized state, a) at least 7% wt and at most 49% wt of iron, Fe, b) at most 1.3% wt of copper, Cu, c) at least 24% wt and at most 44% wt of silicon dioxide, SiO.sub.2, d) at least 1.0% wt and at most 20% wt of calcium oxide, CaO, e) at least 0.10% wt and at most 1.50% wt of zinc, Zn, f) at least 0.10% wt and at most 2.5% wt of magnesium oxide, MgO, and g) at most 0.100% wt of lead, Pb. Further disclosed are improved construction elements comprising the slag.

Disclosed is a method of fabricating a construction element, the method comprising the manufacturing of a construction element including a slag, wherein the slag is comprising, on a dry basis and whereby the presence of a metal is expressed as the total of the metal present as elemental metal and the presence of the metal in an oxidized state, a) at least 7% wt and at most 49% wt of iron, Fe, b) at most 1.3% wt of copper, Cu, c) at least 24% wt and at most 44% wt of silicon dioxide, SiO.sub.2, d) at least 1.0% wt and at most 20% wt of calcium oxide, CaO, e) at least 0.10% wt and at most 1.50% wt of zinc, Zn, f) at least 0.10% wt and at most 2.5% wt of magnesium oxide, MgO, and g) at most 0.100% wt of lead, Pb. Further disclosed are improved construction elements comprising the slag.

A method for recovering metal values from a molten slag composition includes atomizing the slag with an oxygen-containing gas in a gas atomization apparatus, to produce solid slag granules. Oxygen in the atomizing gas converts metals to magnetic metal compounds, thereby magnetizing the metal-containing slag granules. These metal-containing slag granules are then magnetically separated. Larger amounts of metals may be removed by passing the molten slag through a pre-settling pan with an adjustable base, and/or discontinuing atomization where the metal content of the slag exceeds a predetermined amount. Solid slag granules produced by atomization may be charged to a recovery unit for recovery of one or more metal by-products. An apparatus for recovering metal values from molten slag includes a gas atomization apparatus, a flow control device for controlling the flow of atomizing gas, a control system, and one or more sensors to detect metal values in the slag.

A method for recovering metal values from a molten slag composition includes atomizing the slag with an oxygen-containing gas in a gas atomization apparatus, to produce solid slag granules. Oxygen in the atomizing gas converts metals to magnetic metal compounds, thereby magnetizing the metal-containing slag granules. These metal-containing slag granules are then magnetically separated. Larger amounts of metals may be removed by passing the molten slag through a pre-settling pan with an adjustable base, and/or discontinuing atomization where the metal content of the slag exceeds a predetermined amount. Solid slag granules produced by atomization may be charged to a recovery unit for recovery of one or more metal by-products. An apparatus for recovering metal values from molten slag includes a gas atomization apparatus, a flow control device for controlling the flow of atomizing gas, a control system, and one or more sensors to detect metal values in the slag.