Decanter centrifuge for separating feed suspension into fractions and method for operating same

摘要

A decanter centrifuge for separating a feed suspension of a particular solid material in a liquid into two fractions, i.e. a heavy fraction containing heavy particles and a light fraction containing light particles, or no particles at all, is described. The centrifuge has a rotatably mounted elongated bowl having closed ends with a side wall extending therebetween. A helical scroll is rotatably mounted coaxially within the bowl, and the bowl and the scroll may be rotated at different rotational speeds. A pipe coaxially mounted in a tubular shaft and rotatably supporting the scroll, feeds the suspension into the bowl. Several outlets in the wall of the bowl discharge the heavy fraction from the bowl. The light fraction travels through the length of the bowl by the helical scroll and is discharged from outlets located downstream from those that discharge the heavy fraction. The delivery region is also nearer to the outlets for the heavy fraction than to the outlets for the light fraction. The centrifuge can be used for concentrating an aqueous suspension of an inorganic particulate mineral material, such as kaolin, metakaolin, calcium carbonate, or calcium sulphate or for separating such a material into heavy and light fractions, eg. to produce a finer fraction product.