Stack for the thermal treatment of material

Abstract

Wall structure for a smelting stack is comprised of a cooling fluid flow pipe membrane layer comprised of a series of vertical, parallel arranged pipes extending between upper and lower manifold members. The pipe membrane completely surrounds a hot zone in the smelting stack. The upper and lower manifolds extend interiorly of the pipe wall membrane to define an alcove in which there is positioned a series of vertically arranged lengths of insulation cladding which are spaced from one another by gaps filled with fire-proof materials. The gaps contain elements of the pipe membrane layer directed interiorly of the pipe membrane. A waste-gas stack may be mounted directly adjacent the smelting stack with a common wall therebetween. The waste-gas stack wall comprises only a pipe membrane. The primary function of the stack wall structure in the waste-gas stack is to remove heat from the waste gases; whereas, the primary function in the smelting stack is to retain heat within the stack and enable the furnace wall structure to withstand the smelting heat. A common wall serves both these functions. Since the load-bearing elements of the wall structure are the pipe membranes, the stack wall structures may be supported in a blast furnace system by suspension from the upper manifold or erection upon the lower manifold.