The document discusses various factors affecting particle screening, including particle shape, size, and mesh characteristics. It outlines methods for data representation in screen analysis such as histograms, frequency plots, and cumulative size distributions, supported by examples. Additionally, it briefly mentions industrial screening equipment types and presents calculations related to particle analysis and screen effectiveness.

1. Factors Affecting Screening
1) Presence of near mesh particles
2) Shape of particles
3) Size of Particles
4) Motion
5) Nature of particles
6) Humidity or moisture
7) Mesh size and wire diameter
8) Capacity
9) Blinding

2. Screen Analysis

3. Screen Analysis

4. Table : Sample screen analysis

5. Methods of Tabulation & Plotting Screen Analysis Data
❑ Histogram:
▪ The results could be represented as a histogram, such as shown in Figure.
The vertical axis would be the mass fraction of the total sample between
two screens, which is plotted versus the particle size or screen aperture

6. ❑ Fractional or Frequency Size Distribution Plot:
▪ In this curve, it is assumed that the material between two screens have a
particle diameter as the arithmetic mean of the two screen openings. The
mass fraction of the material retained is plotted against the average
particle size as shown in Figure

7. ❑ Cumulative Size-Distribution Plot:
▪ This curve is obtained by plotting the mass fraction of particles having a
size larger or smaller than a given screen opening versus the average
particle size as shown in Figure

8. ❑ Log-Probability Plot :
▪ This plot is obtained by plotting the log of the screen aperture versus the
cumulative percent undersize (or oversize) as shown in Figure.
➢ In many cases, it is more convenient
to plot the distribution curves on
semi-logarithmic coordinates so that
the mass fraction is plotted as a
function of the logarithm of the
particle size in order to avoid
crowding the data into a small
section of the diagram.

9. Mixed particle sizes and size analysis
of

12. Average particle size

14. The Number of Particles in a mixture

15. Example:
The screen analysis shown in Table E-1 applies to a sample of crushed quartz. The
density of the particles is 0.00265 𝐠/𝐦𝐦𝟑
, and the shape factors are 𝒂∗
=2 and
𝝋𝒔=0.571. For the material between 4-200- mesh in particle size, calculate:

16. Table E-1. The screen analysis

17. Solution:

19. Home work 2:
The screen analysis shown in Table E-2 applies to a sample of crushed pyrite. The
density of the particles is 5000 𝒌𝐠/𝐦𝟑, and the shape factors are 𝒂∗ =0.5236 and
𝝋𝒔=0.735. Calculate:
1. 𝑨𝒘 , 𝑵𝒘, ഥ
𝑫𝒗, ഥ
𝑫𝒔, ഥ
𝑫𝒘.
2. The number of particles 𝐍𝐢 in each mesh increment.
3. The fraction of the number of particles
𝐍𝐢
𝐍𝐓
in each mesh increment.

20. Table E-2. The screen analysis

21. Material balance over screen

22. Eq. (15)
Eq. (16)

23. Calculate screen effectiveness
Eq. (17)

24. Example:
A quartz mixture having the screen analysis shown in Table E-3 is screened through a standard 10-
mesh screen. The cumulative screen analysis of overflow and underflow are given in Table E-3.
Calculate the mass ratios of the overflow and underflow to feed and the overall effectiveness of the
screen.
Table E-3 the screen analysis of a quartz mixture

25. Solution:
The cut-point diameter is the mesh size of the screen is 1.651 mm, so for this screen:
(15)
(17)

26. Industrial screening equipment
- Grizzlies screens– Vibrating screens – Gyratory screens – Trommels screens –
Banana screens

27. Industrial screening equipment

28. Industrial screening equipment

29. Industrial screening equipment

30. Industrial screening equipment

31. Industrial screening equipment

32. Industrial screening equipment

33. Industrial screening equipment

34. Industrial screening equipment