Limestone, Dolomite, Talc, Barite, Perlite
The fillers that were considered ultra-fine just a few years ago are now standard products. The filler market may be large but is is also fiercely competitive. The requirements are therefore either fine fillers with a sharp top cut at low costs or custom-made particle size distributions.
These specifications are not sufficient to enable selection of the optimum system, however – instead, it is necessary to consider the different products and their properties, e.g. the laminar structure of talc, the micro-crystalline structure of chalk, etc. The maintenance costs, product change and space requirement, to name just a few aspects, must also be taken into consideration. The two diagrams and the table give an overview of the different grinding and classifying systems used for fillers.
Fine fillers – high performance
Limestone (CaCO3) is one of the most important, versatile and – in terms of quality – most frequently used minerals. It is common throughout the world and is used in the plastics, rubber, food-stuffs, chemical and pharmaceutical industries.
An application example is the limestone or calcite with and end-product fineness of 99% < 8.5 micron (d50 = 2.0 micron) at throughput rates of approx. 8 t/h.
Our solution for this application is a large S.O 300/600 ball mill in circuit with a Turboplex classifier 630/4 ATP, paired with an efficient control unit with in-line particle size analysis to control the fineness.
Although dolomite – similar to limestone and calcite – is also used for ultra-fine fillers, the main customers are the glass, ceramics and steel industries, who demand medium-fine products or even steep particle size distributions. In the medium-fine range d97 = 45 – 100 micron, energy considerations make the table roller mill AWM an ideal choice. Unsalable scrap granules from the preliminary crushing step usually serve as feed material for the AWM.
Ball Mill Super Orion S.O.-SF (SuperFine)
This system combines the robustness of a ball mill with a high-efficiency ultra-fine classifier. The direct pneumatic transfer of the feed material onto the classifier saves on the necessity for susceptible conveying units and guarantees an extremely compact, inexpensive configuration. The modern control unit and the in-line particle size analysis unit make it possible to run the system for several shifts without personnel. This solution has enabled our customers to secure substantial market advantages for themselves.
Agitating ball mill with multi-wheel classifier
Hosokawa Alpine ATR agitated ball mills are absolutely ideal for the dry production of superfine mineral powders of less than 10 micron in size. Fineness values to 95% < 2 micron with a high specific surface can be obtained. The ATR technology ensures optimum energy utilization at maximum system reliability. The combination of these process qualities guarantees extremely cost-effective operation.
Table roller mill AWM
Table roller mill are robust and proven mills for medium-hard mineral raw materials and industrial bulk goods with fineness values of d97 = 10 micron. They are characterized by their compact design, high throughput rates and low energy requirement.