Abstract: A concrete product which uses 100% of the melt slags and pulverizes the melt slags into aggregates and fine powders, grinds the aggregates so that the percentage of absolute volume of the aggregates is over 60%, mixes the aggregates, fine powders, water and cement, and forms the mixture into the concrete product by vibration or press molding.

Abstract: A waste melting furnace has a coke layer formed therein, and an annular combustion space formed circumferentially of the coke layer below an upper surface thereof and communicating with the coke layer. A depending wall projects downwardly from an upper position of the combustion space to mark a boundary between the combustion space and the coke layer. A waste is fed in powder form into the combustion space, and burned in the combustion space and the coke layer to be melted and slagged. The depending wall prevents the waste from passing directly into exhaust gas, and causes the waste to remain in the combustion space for a prolonged time before flowing into the coke layer.

Abstract: A melting disposal method of sludge. The method of the invention having the steps of collecting a plurality of cakes of dehydrated sludge generated at a plurality of sewage disposal plants at one melting disposal plant; incinerating or drying a substantially fixed amount or proportion of the dehydrated sludge cakes; mixing the resultant substance; and heat-melting the resultant mixture with addition of basicity conditioning agent.

Abstract: An incinerating-fusing system for city refuse is disclosed. The system includes an incinerating furnace for incinerating city refuse, a fusing furnace for fusing ash from the incinerating furnace at a high-temperature hearth formed of carbon type combustible material, a communicating passage directly communicating an ash chute of the incinerating furnace with the fusing furnace, the communicating passage acting for dropping ash from the incinerating furnace and also for upwardly exhausting exhaust gas from the fusing furnace. The system further includes a dust collector disposed in an exhaust gas passage extending from the incinerating furnace and a dust conveying passage extending from inside of a high-temperature hearth of the fusing furnace so as to introduce dust from the dust collector.