Theory and practice

Drying in mineral processing

Summary: Proper and professional design of equipment for drying solid and free-flowing materials requires, in addition to extensive theoretical knowledge, specific practical ­experience. Irrespective of this, this experience is backed up by test centre trials. On this basis, it is possible to meet the high market requirements for the reliability and cost ­efficiency of the plant engineering and comply with specified guarantee values. In this paper, typical applications based on theoretical principles are presented. The focus is on HAZEMAG rapid dryers and combined grinding and drying in HAZEMAG hammer mills. Trials conducted at the test centre forge the link between theory and practice and enable well-founded planning and realization of the drying equipment.

1 Basis principles of drying technology

During the drying of solid, free-flowing materials, the key objective is to separate the materials from any moisture. The moisture is generally water, but can basically be any other liquid or solution. In many materials, moisture is already naturally inherent. It may, however, also have been added by the methods of mineral processing (e.  g. wet washing), so that here too separation may be necessary.


In contrast to dewatering, where moisture removal is performed by mechanical methods (e.  g. pressure, gravitational forces, centrifugal forces), in thermal...

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