Continuous Ball Mill Systems | Screen Discharge Mills | Batch Ball Mills
The new ball mills
For the forms of new ball mills, there are three forms, such as Continuous Ball Mill Systems, Screen Discharge Mills.
Continuous Systems
Open-Circuit Grinding
• Applicable to continuous operation
• Finished product is obtained from a single pass through the mill
• Typically produces a wide particle distribution with a high proportion of superfines in the product
• Requires careful selection of length/diameter ratio of the mill and diaphragm design to ensure correct residence time and product fineness.
Closed-Circuit Grinding
• Applicable to continuous operation
• Mill product is fed to a classifier controlling final product size
• Oversize material is returned from the classifier to the mill for further reduction
• Capable of achieving top size products of the order of 10 microns or finer with appropriate classifier
• Typically produces a narrower particle size distribution than open-circuit with accurate control of maximum particle size
• Minimises over grinding, resulting in improved milling efficiency, lower specific power consumption and smaller mill for given capacity
Air swept Milling
• Applicable to dry closed-circuit milling only
• Operates with an airflow passing through the mill providing elementary pre-classification
• Capable of producing top product sizes of the order of 50 microns or finer
• Typically produces a narrow particle distribution with relatively high D50 values
• Enables limited drying of material to be accommodated
Combined Drying and Grinding
• By the provision of a hot air supply to the grinding circuit a limited drying capability can be provided
Iron-free Grinding
• For applications where metal contamination of the product must be minimised; high density alumina, ceramic or silex stone mill liners and grinding media are used
• Other areas of the plant which are subject to wear can be lined with similar abrasion resistant materials
Screen Discharge Type
Screen Discharge Mill is designed for continuous operations and has the characteristics of producing a relatively coarse product with minimum generation of superfines.
The grinding chamber is formed from a set of replaceable cast steel perforated grinding plates bolted to shaft mounted end plates fitted with renewable segmented steel liners. The chamber is totally surrounded by two concentric sets of perforated screens. The chamber contains a steel ball charge.
Material enters through an axially placed feed nave. Ground material passes through the perforated grinding plates onto the inner screen surface.
Material then passes through this screen continuing to the outer screen which controls the final product size. Oversize (or semi-ground) material retained on each screen is returned to the grinding chamber through a series of re
