A grinding mill is a tool that is designed to break a solid material into smaller pieces. There are many different types of grinding mills and many types of materials processed in them. When purchasing/ordering a grinding mill from Classifier Milling Systems, we always seek to give advice to our clients, and to understand the nature and characteristics of whatever they want to grind.
Characteristics of Material used in selection of a Grinding Mill
The characteristics of the material, which are to be taken into account during the selection of the grinding mill, are
(vi) softening and melting temperature
(vii) structure (e.g. close grained or cellular)
(viii) specific gravity
(ix) free moisture content
(x) chemical stability
The hardness of a material is possibly the most important characteristic to be considered when deciding on what type of mill to choose. Trying to grind a material which is too hard results either in costly damage to the mill or an expensive maintenance requirement. Generally, for harder materials, specialized and expensive type of grinding mills are used. In addition, if a particular mill can be used over a range of hardness scales, the harder the material the lower the throughput for a given size requirement.
Another characteristic of a material that is to be known is the brittleness, which is the degree to which a material breaks easily. Most minerals are brittle, as opposed to metals which are ductile, although some to a greater degree than others. Brittleness does not equate with hardness as brittle materials can be hard or may not be hard. It is not easy to grind materials which are not brittle to some degree.
The grinding mills are categorized in three groups, namely
(i) tumbling mills
(ii) roller mills
(iii) very fine grinding mills which include:
(a) high speed pulverizing or hammer mill
(b) vibrating mill
(c) pin mill
(d) turbo mill
(e) fluid energy mill
(f) stirred media mill