1. SLURRY CONVEYING
Suspensions Solid - Liquid
Mario Cerda C.
BE mech
Mario.cerda.c@gmail.com
06/05/12

2. Objetives
 Extend the theoretical and practical
knowledge for the selection, design and
evaluation of fluid drive systems for the
transport of Newtonian heterogeneous
slurries.
06/05/12

3. Introduction
 Aplication of slurry transport systems in mining industry :
 Concentrate from mine to port o estaciones ferroviarias (BHP - Escondida,
Anglo American- Collahuasi, PLC AM – Los Pelambres, Codelco - Andina)
 Tailing disponsal systems (Codelco - El Teniente, Codelco - Andina,
Freeport McMoran - Candelaria)
 Etc, etc, etc……
06/05/12

4. Introduction
 Examples
Compañía Producto Tipo conducción Dimensiones Largo (kms) Producción (KTD) Inicio
Teniente Relaves Canal de concreto ancho : 1,4 m 80 110 1983
Disputada Mineral Tubería de acero diámetro : 20" 56 37 1992
Escondida Concentrado Tubería de acero diámetro : 6" y 9" 185 4-5 1992 - 1995
Iscaycruz (Perú) Concentrado Tubería de acero diámetro : 3,5" 25 1 1996
Alumbrera (Argentina) Concentrado Tubería de acero diámetro : 7" 240 - 300 3-3 1997
Collahuasi Concentrado Tubería de acero diámetro : 7" 195 3 1998
Andina Relaves Canal de concreto ancho : 1,2 m 87 65 1998
06/05/12

5. Rheological Aspects
 Definition of viscosity
06/05/12

6. Rheological Aspects
Rheologic Diagrams
.
 Newtoniano :τ = µ * γ
. n
Pseudoplastic :τ = K *γ n <1
. n
Dilat ant :τ = K γ n >1
.
Bingham :τ = τ 0 +η *γ
. n
Yield − power Law : τ = τ 0 + η * γ
du .
06/05/12 =γ
dy

7. Characterization of Newtonian
Slurries
 Most of the particle with size above 50 µm.
 Concentration of solid by weight (Cp or Cw), less than 70%.
 Concentration of solid by volume (Cv), less than or equal to
40%.
06/05/12

8. Characterization of Newtonian
Slurries
 Basic Parameters
 Particles size (d20, d50, d80 y d85)
 Concentration of solids, by weight or volume
 Density of solid (ρp)
 Density of liquid (ρl)
 Viscosity
06/05/12

9. Viscosity
 More Popular Viscosity Model
 Einstein
μ P = μ L ( 1 + 2.5CV )
(
μP = μL 1 + 2.5CV + 10.05CV + 0.00273e16.6 CV
2
)
 Thomas
06/05/12

10. Newtonian Slurries
Homogeneous (Non Settling slurries)
All Particles with size less than 50µm, and with low concentration of solids can be
treated as heterogeneous slurries.
Heterogeneous (Settling slurries)
Type A
50µm < Particle size < 300µm and Cp ≤ 40%
Type B
50µm < Particle size < 300µm and Cp > 40%
Type C
Particle size > 300µm and Cp < 20%
Type D
Particle size > 300µm and Cp > 20%
06/05/12

11. Slurry Conveying in Piping
Systems
 The most important factors for the transport of slurry in pipes are :
 Settling velocity
 Head loss
 The limit velocity or settling velocity, determines the minimum flow rate so
that there is no risk of deposition and blockage of the pipe
 The definition of the beginning of the speed limit has little variation between
researchers, not knowing those differences can make the design fail.
V V : Slurry velocity
> 1.0 VL : Settling velocity
VL
06/05/12

12. Slurry Conveying in Piping
Systems
06/05/12

13. Settling Velocity Models
.
Durand - Condolios
 Durand
VC = FL 2 gD( S − 1)
 Durand modified by Juan Rayo
VC = 1.25 ⋅ FL [ 2 gD( S − 1) ]
0.25
Mc Elvain - Cave
 Wasp
1
 d 50  6
VC = 3.116C 0.186
V 2 gD( S − 1)  
 D
06/05/12

14. Effects of Diameter of Pipe
6,00
5,50
5,00
4,50
4,00
VEL. CRITICA (m/s)
3,50
3,00
2,50
2,00
1,50
1,00
0,50
0,00
0
0,2
0,3
0,4
0,5
0,7
0,9
1
1,1
0,1
0,6
Diametro tuberia (m) 0,8
WASP DURAN JRI PROM W&D PROM ALL
06/05/12

15.  Effects of Particle Size d50
6,00
5,50
5,00
4,50
4,00
VEL. CRITICA (m/s)
3,50
3,00
2,50
2,00
1,50
1,00
0,50
0,00
0,001 0,01 0,1 1 10
D50 (mm)
WASP DURAN JRI PROM W&D PROM ALL
06/05/12

16. Steps to Calculate a System of
Transport of Solids
1. Characterization of flows.
2. Static height.
3. Slurry Correction Factor of the efficiency and dynamic height.
4. Diameter of the pipe.
5. Determination of Settling velocity.
6. Calculation of head losses.
7. Calculation of total dynamic height (TDH).
8. Selection of the pump and the material.
9. Determination of the operating speed
06/05/12

17. Steps to Calculate a System of
Transport of Solids
1. Required motor and Power
2. Others.
 NPSH
 Casting Pressure
 Froth pumping
 Conical enlargement
 Pump feed hopper
 Shaft sealing
 Multi staging
 Drive selection
06/05/12

18. Slurry Correction Factor of the
efficiency and dynamic height
 Curves supplied by the manufacturer corresponds to pump operation with
pure water.
 The correction factor is:
Hw
H =
HR
Where:
 H : Slurry TDH
 Hw : Water TDH
 HR : Slurry Correction Factor
06/05/12

19. Slurry correction Factor HR
 McElvain & Cave model for HR
K × Cv
HR = 1 -
20
where:
K S
K = K ( S, d 50 ) 0.50 8.00
0.45 5.00
4.00
0.40
3.00
0.35 2.55
0.30
2.00
0.25
1.80
0.20
0.15 1.25
0.10
1.10
0.05
0.00
0.01 0.1 1.0 10.0
06/05/12
D50 [mm]

20. Slurry correction Factor HR
 The Warman Pumps Models for HR
06/05/12

21. Slurry correction Factor HR
 The Weir Pumps model for HR
06/05/12

22. Cerda Model for HR & FL
Limite settling velocity factor (FL)
[ ] [
Fl = 1.4Cv0.045 + ( 0.18 + 0.006 ln ( Cv ) ) ln ( d 50 ) * 0.042d 50 − 0.218d 50 + 0.265d 50 + .96
3 2
]
Slurry correction factor HR & ER
HR = a( c ln( d 50 ) + d ) + 1
where :
a = −0.1605C p + .000466
ρs
b=
ρl
c = 0.0133b 3 − 0.1785b 2 + 1.0555b − 0.8232
d = .04630b 3 − 0.6361b 2 + 3.8714b − 2.9632
06/05/12

23. Additional Design
Considerations
 Flow Rates
 The slurry volumetric flow (Q), is :
Qs  1 1  m3 
Q = ×  -1 - 
C
3.600  p S  s 
 

donde
Qs : metric tons of solid transported per hour
Cp : Concentration of solids by weight
S : relative density of solids
06/05/12

24. Additional Design
Considerations
 In the case of restricted systems, you must manipulate the % solids in order to
maintain constant flow.
 The minimum flow will be given for a minimum production (Qs)min and maximum S
and Cp.
 The maximum flow will be given for maximum production (Qs)max and minimum S
and Cp.
 Transportable minimum flows (Qs), are defined by the minimum settling velocity.
06/05/12

25. Questions….
The End..
Fin..
Fine..
Ende..
06/05/12