| 摘要 |
Solid materials are efficiently calcined in a single column kiln by effecting said calcination through a plurality of vertically arranged zones, by means of a method comprising the steps of feeding said solid materials to a preheating zone wherein the materials are preheated countercurrently with combustion gases, allowing said preheated materials to fall to an air preheating zone to which primary air is fed in parallel flow with said falling preheated materials, allowing said materials to fall to a calcining zone to which fuel is admitted in parallel flow with said preheated air, allowing the thus calcined materials to fall to a cooling zone to which secondary cold air is fed countercurrently with said falling materials, exhausting the combustion gases produced in the calcining zone together with said secondary air which was preheated by the calcined materials, at a point between said calcining and cooling zones, and feeding said combustion gases and secondary air as a mixture to the preheating zone. The kiln comprises a vertical elongated receptacle divided by partition means into an upper or preheating chamber and a lower chamber which includes said primary air preheating zone, said calcining zone and said cooling zone, material feed means at the top of said upper chamber, material transfer means between said upper and said lower chambers, and material discharge means at the bottom of said lower chamber.
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