On molten iron having a P concentration of 2 to 4 mass % and having a Cr concentration of 0.3 to 1.2 mass %, a dechromization treatment is performed by adjusting a basicity (CaO mass %)/(SiO.sub.2 mass %) of slag to greater than 0.1 and 1 or less and supplying an oxygen source with a molten iron temperature falling within a range of 1250 to 1500° C. to manufacture molten iron having a P concentration of 1.9 to 3.8 mass % and having a Cr concentration of less than 0.2 mass %.

The invention relates to a method and an arrangement for wastewater treatment, in which at least portions of the sewage sludge contained in the wastewater (0) are subjected to a hydrolysis (8). The hydrolysis (8) is carried out as a thermal hydrolysis. After the hydrolysis step (8), a drying process is (19) carried out. The drying process (19) is a process operating with positive pressure in the steam region. At least parts of the steam resulting from the drying process (19), which operates with positive pressure, are fed (20) to the portions of the sewage sludge in the thermal hydrolysis (8).

The invention relates to a method and an arrangement for wastewater treatment, in which at least portions of the sewage sludge contained in the wastewater (0) are subjected to a hydrolysis (8). The hydrolysis (8) is carried out as a thermal hydrolysis. After the hydrolysis step (8), a drying process is (19) carried out. The drying process (19) is a process operating with positive pressure in the steam region. At least parts of the steam resulting from the drying process (19), which operates with positive pressure, are fed (20) to the portions of the sewage sludge in the thermal hydrolysis (8).

On molten iron having the P concentration of 2 to 4 mass % and having the Cr concentration of 0.3 to 1.2 mass %, a dechromization treatment is performed by adjusting a basicity (CaO mass %)/(SiO.sub.2 mass %) of slag to greater than 0.1 and 1 or less and supplying an oxygen source with a molten iron temperature falling within a range of 1250 to 1500 C. to manufacture molten iron having the P concentration of 1.9 to 3.8 mass % and having the Cr concentration of less than 0.2 mass %.

The present disclosure provides a method for producing value-added by-product yellow phosphorus slag through an unconventional electric furnace process, derived from yellow phosphorus. This method is related to the technical field of comprehensive utilization of mineral resources. The disclosed method involves the following steps: mixing mid-low-grade phosphate rock, silica, coke, and a cosolvent to create a blended material, subjecting the blended material to high-temperature reduction in a yellow phosphorus electric furnace to yield yellow phosphorus and water-quenched slag, and then drying the water-quenched slag using yellow phosphorus tail gas to obtain the yellow phosphorus slag. According to this disclosure, a P.sub.2O.sub.5CaOSiO.sub.2MgOR multi-component system is established using the blended material.

The present disclosure provides a method for producing value-added by-product yellow phosphorus slag through an unconventional electric furnace process, derived from yellow phosphorus. This method is related to the technical field of comprehensive utilization of mineral resources. The disclosed method involves the following steps: mixing mid-low-grade phosphate rock, silica, coke, and a cosolvent to create a blended material, subjecting the blended material to high-temperature reduction in a yellow phosphorus electric furnace to yield yellow phosphorus and water-quenched slag, and then drying the water-quenched slag using yellow phosphorus tail gas to obtain the yellow phosphorus slag. According to this disclosure, a P.sub.2O.sub.5CaOSiO.sub.2MgOR multi-component system is established using the blended material.

[Problem] To provide a method for producing useful substances, which converts organic waste containing heavy metals into harmless substances such as fertilizers and soil conditioners by carbonizing organic matter while detoxifying heavy metals.

[Solution] The present invention is a method for producing a useful material, said method comprising treating an organic waste in which heavy metals are mixed to produce a carbonized material containing weighed material. The organic waste in which the heavy metals are mixed is treated by dry carbonization of an organic waste to which a Ca component starting material and a SiO.sub.2 component starting material, which are topalmorite starting materials, are added in amounts sufficient to contain the mixed heavy metals in topalmorite crystals; a charcoal-forming step of dry carbonizing the waste, carbonizing the organic waste to form a carbide; the carbide formed in this carbide forming step and the topamolite raw material are charged into a reaction vessel while maintaining the high temperature state in the previous step, and slowly cooled in the presence of water with stirring to form the organic material; a heavy metal confinement step of forming a topamolite crystal mineral in which heavy metals mixed in the organic waste are confined, and forming a slurry in which the carbide and the topamolite crystal mineral are dispersed; and drying or dehydrating the slurry formed in the previous step to produce a useful substance containing a carbide containing the topamolite crystal mineral.

[Problem] To provide a method for producing useful substances, which converts organic waste containing heavy metals into harmless substances such as fertilizers and soil conditioners by carbonizing organic matter while detoxifying heavy metals.

[Solution] The present invention is a method for producing a useful material, said method comprising treating an organic waste in which heavy metals are mixed to produce a carbonized material containing weighed material. The organic waste in which the heavy metals are mixed is treated by dry carbonization of an organic waste to which a Ca component starting material and a SiO.sub.2 component starting material, which are topalmorite starting materials, are added in amounts sufficient to contain the mixed heavy metals in topalmorite crystals; a charcoal-forming step of dry carbonizing the waste, carbonizing the organic waste to form a carbide; the carbide formed in this carbide forming step and the topamolite raw material are charged into a reaction vessel while maintaining the high temperature state in the previous step, and slowly cooled in the presence of water with stirring to form the organic material; a heavy metal confinement step of forming a topamolite crystal mineral in which heavy metals mixed in the organic waste are confined, and forming a slurry in which the carbide and the topamolite crystal mineral are dispersed; and drying or dehydrating the slurry formed in the previous step to produce a useful substance containing a carbide containing the topamolite crystal mineral.

An horticultural blend is disclosed. The horticultural blend includes coal refuse and slag blended with at least a portion of the coal refuse. The coal refuse has a particle size, the particle size corresponding with all material in the coal refuse having a maximum dimension of less than about 2 inches and at least about 25% of the material in the coal refuse being capable of passing through a standard number 4 sieve. The horticultural blend has a pH within a range of about 3.5 and about 10 and the horticultural blend facilitates growth of vegetation when applied to a coal refuse pile at a thickness of less than about 2 feet.

An horticultural blend is disclosed. The horticultural blend includes coal refuse and slag blended with at least a portion of the coal refuse. The coal refuse has a particle size, the particle size corresponding with all material in the coal refuse having a maximum dimension of less than about 2 inches and at least about 25% of the material in the coal refuse being capable of passing through a standard number 4 sieve. The horticultural blend has a pH within a range of about 3.5 and about 10 and the horticultural blend facilitates growth of vegetation when applied to a coal refuse pile at a thickness of less than about 2 feet.