| 摘要 |
A process is claimed for passivation or regeneration of sandy or granular products by a thermal route in which the product is introduced into an airtight enclosure incorporating two distinct zones, the product being fluidised by air or gas into a deep layer. The first, upper zone is for the thermal treatment of the product and has peripheral and central heating whilst the second, lower zone is for cooling the product by the passage of the air or gas that is used for the fluidisation of the product. The process is carried out in an enclosure with an upper high temperature zone heated by burners and a lower cooling zone. The product rests on a porous bed in order to allow the passage of the fluidising air or gas, this being preheated during the cooling stage prior to its introduction to the upper heated zone. USE/ADVANTAGE - The process is used for the passivation or regeneration of sandy or granular products, notably foundry sands to permit their re-use or discharge in an inert state, by eliminating or passivating the chemical products contained in these products. The process is more economic in operation than conventional thermal treatments applied to foundry sands.
|
