Compaction of Talc:

Talc is used in diverse sectors. Among those diverse sectors, the plastics industry plays a major roll with using talc as an additive for polypropylene. Those polypropylenes are applied in the automotive industry for improving the mechanical properties of bumpers, for improving the shape accuracy of the interior and for extending the temperature range in the technical area.

High bulk weight combined with good dispersibility are the most important characteristics for the implementation of talc in the plastics industry. Furthermore, the granulating procedure should possibly work without water because otherwise the material would have to be degassed in a complex way for further processing it in extruders.

The compaction of talc on roller presses meets those demands. Due to the relative low bulk weight of fine talc, the roller presses must be equipped with a vacuum de-aeration for this purpose. Depending on the feeding material and its grain size, different throughput capacities can be achieved with a roll press of the ARC MS series.

Process:

The KOMPAKTOR  is designed for the de-aeration of talc (densification). A high bulk density without creation of hard spots will be achieved during the densification process.

The powder will be fed into a large silo above a horizontal screw. An agitator or vibration nozzles above the screw prevent any bridging of the light talc powder. The horizontal screw has a vacuum de aeration system for increasing the efficiency of the screw and increasing the throughput of the Compactor.

The material will be fed withmultiple screws into the gap of the compaction rolls. In the conical hopper of the multiple screw feeding unit there will be also a vacuum de-aeration system.

The talc will be compacted to soft flakes in the roller gap of the Compactor ARC MS series.  After compaction the material is normally packed into super sacks or normal bags.

During the compaction/granulation process this fine dust will be granulated to dust free granules with a bulk density of more than 500 g/l.

Example for ARC-MS 60

– Feeding bulk weight:  g/l = 12.5 lb/ft³

– Final bulk weight:  min. 600 g/l = 37.5 lb/ft³

– Throughput:  approx. 4 Mtons/h

– Feeding bulk weight:  280 g/l = 17.5 lb/ft³

– Final bulk weight:  min. 600 g/l = 37.5 lb/ft³

– Throughput:  approx. 6 Mtons/h

With this process, bulk weights up to 800 g/l = 50 lb/ft³ can be obtained, irrespective of the feeding material. However, this results in a reduced throughput capacity.

With talc qualities as being used in the paper industry (feeding bulk weight approx. 300 g/l = 20 lb/ft³), bulk weights of approx. 1.000 g/l (= 62 lb/ft³) can be gained. The throughput of an ARC MS 75 machine ranges in this case between approx. 5 – 6 Mtons/h.