How to choose a conventional mill？
2018-01-05 16:57Introduction：In order to distinguish self mills from conventional mills, the mill with mental mediums (Like balls and rods) added are called conventional mills, such as Ball Mills and Rod Mills . They each has different features. How to choose an appro
In order to distinguish self mills from conventional mills, the mill
with mental mediums (Like balls and rods) added are called
conventional mills, such as Ball Mills and Rod Mills . They
each has different features. How to choose an appropriate
mill according to the nature of the ores and material’s size
according to the Beneficiation Process? It plays a very important
role on getting high grinding efficiency and improving the
economical effects of grinding requires. Ball mills and rod mills
ore factory always use have following features and applications.
(1) Grate type Ball Mill
Due to the existence of grid plate and elevator bucket in fan
chamber, grate mill realizes low-level forced discharge. As a result,
fine mineral particles can be discharged in time and qualified particles
will not stay too long in the mill, which makes less over-crushing
phenomena, faster grinding speed , and higher efficiency.
As the slurry level of the mill is lower and the ores are in smaller
quantity, together with the “separation” effect of grating, on the one
hand, higher media filling rate can be adopted for increasing ball charge
with appropriate amount of small balls; on the other hand, when the ball
is lifted to certain height, it has a considerable falling height compared to
the lower slurry level. Therefore, the impact effect of media ball is rather
strong, which is of excellent crushing and grinding effect.
As the mill is of high discharging speed, the dwelling time of ore is
relatively shorter. The grinded ores can be transferred quickly from the
mill to Classifier for further opearation, which is helpful for the mill to be
compensated with more ores. Meanwhile particles of large size would not
dwell long in the mill, which reduces over-crushing and improves productivity.
Compared with the overflow type of the same specification, the output
capacity is 10%～25% higher. It is applicable to single-stage coarse grinding
and the first stage of two-stage grinding, and also the grinding of easily-crushing
and soft ores.
(2) Over-flow type ball mill
Over-flow type ball mill discharges because the hollow shaft diameter at
discharging side is bigger than that in feeding side, making pulp surface of the
mill tilts towards the discharging side. When the position of the pulp is higher
than minimum bus of the discharging mouth’s diameter, the pulp will overflow
the mill. This is none-forced discharging, so that the discharging speed is low,
ores staying long in the mill and media’s effect is unclear. As a result, over-flow
type ball mill has serious over-crushing phenomena, and the capacity is lower
than the same type grate ball mill. Over - flow type ball mill is suitable for fine
grinding or second –period crushing.
(3) Rod mill
The media in rod mill are rod, which will contact ore material after falling down.
It has the chose function, that is, the Rod mill can crush materials in turn
according to the size----from the big to small. Thus, rod mill has less over
crushing and even products. It is suitable for primary crushing or gravity
seperating plant requiring little over crushing.
