Abstract: A process for washing a particulate substance comprising: (i) combining a particulate substance and a first washing medium in a first vessel to form a slurry and washing the particulate substance with said washing medium; (ii) transferring the slurry to a hydrocyclone; (iii) removing a first by-product stream depleted in particulate substance and a first product stream enriched in particulate substance from the hydrocyclone; (iv) transferring the first product stream to a second vessel and in the presence of a second washing medium forming a slurry and washing the particulate substance with said second washing medium e.g. by agitation thereof; (v) transferring the slurry to a hydrocyclone; (vi) removing a second by-product stream depleted in particulate substance and a second product stream enriched in particulate substance from the hydrocyclone.

Abstract: The present invention is directed to a process for feeding a polymerisation catalyst into a polymerisation reactor (7), comprising the steps of: (i) maintaining a catalyst slurry comprising a diluent and a solid catalyst component in a catalyst feed vessel (4); (ii) continuously withdrawing a stream of the catalyst slurry from the catalyst feed vessel (4); and (iii) introducing the withdrawn portion of the catalyst slurry into the polymerisation reactor (7), wherein the catalyst slurry is transferred by using a valveless piston pump (5) from the catalyst feed vessel (4) into the polymerisation reactor (7); the diluent has a dynamic viscosity of from 0.01 to 20 mPas at the conditions within the catalyst feed vessel (4), and wherein the catalyst slurry is transferred along a substantially vertical path downwards from the catalyst feed vessel (4) to the reactor (7).

Abstract: The present invention is directed to a process for feeding a polymerisation catalyst into a polymerisation reactor (7), comprising the steps of: (i) maintaining a catalyst slurry comprising a diluent and a solid catalyst component in a catalyst feed vessel (4); (ii) continuously withdrawing a stream of the catalyst slurry from the catalyst feed vessel (4); and (iii) introducing the withdrawn portion of the catalyst slurry into the polymerisation reactor (7), wherein the catalyst slurry is transferred by using a valveless piston pump (5) from the catalyst feed vessel (4) into the polymerisation reactor (7); the diluent has a dynamic viscosity of from 0.01 to 20 mPas at the conditions within the catalyst feed vessel (4), and wherein the catalyst slurry is transferred along a substantially vertical path downwards from the catalyst feed vessel (4) to the reactor (7).