| 摘要 |
The invention relates to a hydraulic binder comprising a stable mixture of alpha-anhydrite and bassanite, wherein the alpha-anhydrite weight ratio is higher than 35%. The process for preparing the hydraulic binder consists in heating the powdery basic material up to a temperature ranging from 220 to 360 degree C, in the presence of water vapours, in suitable conditions to form alpha-type calcium sulphate mostly, the material so heated being then subjected to a thermal quenching operation consisting in cooling the material at a temperature of at least 150 degree C, by means of a cold and dry gas, injected under pressure into the core of the material. in less than 15 min. The claimed installation is provided with a curing tunnel (1), means (15) for supplying the basic material from the upstream end to the curing tunnel (1), longitudinal spouts superposed in the curing tunnel (1), combs of heat conductive material, inserted into the spouts (5), adjusting means (8) for generating the vibration of said spouts (5), adapted to cause the conveyance of the material from the upstream end to the downstream end, heating means, a cooling device (2), a tank (17) of elongated shape, extending in the cooling device (2) for containing the pulverous material, adjusting means for generating the vibration of tank (17), adapted to distribute the material from the upstream end to the downstream end, means for passing the material from the downstream end of the curing tunnel (1) to the upstream end of the cooling device (2) by gravity, means for injecting the cold dry compressed air at the level of the passing means, means (22 and 23)for injecting the cold dry compressed air into the cooling device and means (24 and 25) for discharging the material at the downstream end of the cooling device. |
