Process for heat treating solid material

摘要

In the production of phosphorus from a mixture of phosphate rock, coal, and silica as flux the mixture is charged to apparatus of the type shown in Fig. 1 where it is first heated in the calciner by direct contact with hot gases, to drive off volatile matter. The charge passes through a seal to an indirectly heated reactor, from which phosphorus vapour is recovered in a suitable condenser. Gases leaving the calciner are used to cool the spent charge and are then recycled to the calciner. Hot combustion gases from the fuel firing the reactor may be used to preheat the charge.