| 摘要 |
<p>The main characteristic lies in the fact that the fumes leaving the calcining furnace (22) are used to heat a current of air which is then used, in its turn, to heat the sand to be treated at its inlet to the calcining furnace, and in that the current of air cooled by the sand to be treated is then heated by means of the purified sand leaving the calcining furnace and is then used as combustion air in the calcining furnace.</p> |
