| 摘要 |
Continuous monitoring of the impurity content in a product travelling past in bulk and with a nonuniform thickness on a conveyor belt. The monitored impurity giving a colour reaction with a suitable reagent. …<??>The invention consists of the combination of three means: … … - a means for levelling the upper surface of the product on the belt at least in a certain region, … - a means for spraying the reagent on the surface of the product which is thus levelled, in order to develop the colour by reaction with the impurity … - a means for colorimetric determination of the intensity of the colour obtained with the aid of the reagent. … …<??>The invention applies in particular to the monitoring of the residual sodium hydroxide content in alumina trihydrate obtained in the Bayer process before it is calcined. …<IMAGE>… |
