| 摘要 |
A new process for calcining rocks containing calcium carbonate, in particular lumps of limestone, to hard-burned lime of a given degree of burn comprises the following steps: removal of waste gas, cleaning, cooling and recompression of the latter; mixing of the waste gas so treated with a current of cold air in a weight ratio of 0.1; cooling of the lumps of hard-burned lime with the above-mentioned mixture with controlled, partial recarbonation. The process can be carried out in a double-shaft lime kiln with internal recovery of waste gas and heat, which should be equipped with an extraction duct (1.9) containing a filter (1.10), a heat-exchanger (1.11), a compressor (1.12) with variable-speed motor (1.13) and a delivery duct (1.14) with cold-air feed (1.15), all provided with the necessary measuring and monitoring devices. The process can also be carried out in similarly equipped combined rotary-shaft/lime kiln installations with external recovery of waste gas and heat. |
