Calculation of power
It calculates the power consumption of a ball mill with up to 3 compartments, considering all parameters of the process considering the dimensional analyse of Rose and Sullivan.
With this program you can improve your grinding and merging equipment. It is suitable for application and instruction of technical staff.
The program consists of three parts :
1. Ball Mill Analysing (getting information to run your ball mill properly)
2. Separator Analysing (getting knowlege about your separator)
3. Merging of Fine Materials (information about properties of the mixed products)
1. Ball Mill Analysing
Ball trajectories
This part
of the program explains the ball trajectories by a simulation,
considering the publications of Fischer, Davis, Barth, Rose and
Sollivan, Manz. Parameters are: filling degree, speed, coefficient of
friction, sliding of the charge. Useful for judgement of comminution,
heat transfer to material, pneumatic convaying within the mill.
Example :
Calculation of power
It calculates
the power consumption of a ball mill with up to 3 compartments,
considering all parameters of the process considering the dimensional
analyse of Rose and Sullivan.
>
Charge of Balls
It calculates a ball charge for mills with sorting
plates. The result is the optimal ball size for the corresponding
particles by the empirical formula of Bomd. If necessary you can
chose the smallest balls at the outlet of the compartment.
Medium duration time within the mill
The
program calculates the medium duration time within the
mill. After several vaccination tests with NaCl I found, that the
medium duration time within the mill is a little longer at the inlet
and declines on its way through the mill. The performance depends on
the mill parameters and the throughput. The program also calculates
the transport velocity and the diffusion coefficient within the mill
as well as the standard deviation of the time..
2. Separator Analysing
After entrey of the 3 particle size distributions of the samples of fines, coarse, feed of the separator by hand or by clipboard and saving the values you get :
The Rosin Rammler Sperling Bennet (RRSB)-line in double ln/ln
coordinates
The "Tromp Courve" of the separator, which
gives the courve of separation along particle sizes
The
distribution of size frequency, which gives the graph for the three
samples.
Example for the 3 RRSB lines for feed, fines
and coarse material : 
In addition the following characteristics of
operation are calculated :
Quantity of fines and coarse
Circulation load
n = slope of RRSB-Line, x' = size position
for the passage of 63.2 %
Specific surface in cm²/g
(calculated by RRSB-line)
Tromp courve minimum
Separator
efficiancy
If it is not possible to get a sample of the separator feed, but instead the circulation load by weighing the tailings, you get an approximate calculation
3. Merging of Fine Materials
If you want to achieve an economic comminution in a ball mill or a roller press, the product must not be fully compressed but should contain some spaces. (The greatest amount of space has a "one size powder" with a perpendicular RRSB line.)
So, by a good separator and a well adjusted ball size or preasure of roller press, you get a steep RRSB line and an economic grinding. This is valid for fine and coarse grinding. But it is still necessary that the pressure of the balls or the roller press is heigh enough to achieve an effective comminution.
If you want to have a flater slopt of the RRSB line (in the cement production to minimize the water demand) you can achieve this by mixing of a coarse and a fine powder, each with a steep slope of the RRSB line.
This program gives you a tool to judge the properties of the mixed product after varying the mixing percentages. The particle size distribution of the samples can be saved in a database. Then after 'selection of the samples' you can vary the mixing percentage by a scroll bar and get the changing of the RRSB line or the distribution of frequency.
Variing RRSB line : You
move the slide with the cursor and the RRSB line will follow as well
as every other parameter.
Variing distribution frequency: moving the slide you see how the distribution of size frequency changes.
You will get the following parameters of the mixed products :
>
the slope n and size position x' of the mixed product,
> the
specific surface of the product in Blaine or cm³/cm²,
>
the common specific power consumption, the fractions 0-3, 3-25, 25-50
my.
Besides this you get in a graph the important parameters of the mixture along the percentages of sample 1:
It is also possible to add 1 or 2 fixed components, which do
not participate in the variation.
You can also enter a mixed product into the database, if you want to mix more than one component. Note :In the Help Option you find the used formulas and detailed information. You can use the program in German or in English in Windows 95, 98, NT and 2000.