1. Electrical separation

2. Main parameter - electrical charge

3. Electrical charge depends on: A. Time of life Q t = Q 0 exp (–t/  )= Q 0 exp(–  t/  0 ) Q 0 – electrical charge at the moment of birth (t = 0) Q t – electrical charge at time t t– time  – relaxation time  – conductivity(  –1 m –1 )  – dielectric constant (dimensionless)  0 – electrical permeability of vacuum (8,854·10 –12 C 2 N –1 m –2 ).

4. log  = a + b c a, b – constant c – relative air moisture B. Relative air moisture

5. N - population of particles, E -intensity of electrical field, V/m, q/m -electrical charge per unit mass

7. 1-V.S.Fomienko, NTIS, US Dep. of Commerce Report, No.JPRS- 56579, 1972 lub Gupta et al., Powder technology, 75 (1993) 79- 87, 2 - Lewowski, Coal Preparation Journal, 1993, 13, 97-105, 3 –unknown source, 4. CRC Handbook, 67 th ed., 1986- 87

8. Force F el acting on a charged particle in electrical field F el = Q t E = A q E A - surface area, cm 2 q - surface charge,C/cm 2 E - electrical field, V/m

9. Ways of charging (electrification) - friction (triboelectric) - ionization (ion bombardment) - induction - contact (dissimilar particles) - other