Date post: | 15-Apr-2017 |
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Low Grade Ores - Smelt, leach or concentrate?
1
Sharif Jahanshahi and Terry Norgate
Meta-Logical Solutions
Decline in Australian Ore Grades
2
0
5
10
15
20
25
30
35
40
1840 1855 1870 1885 1900 1915 1930 1945 1960 1975 1990 2005
Ore
Gra
des
(Cu,
Pb,
Zn,
Au,
Ni,
U, D
iam
onds
)
0
325
650
975
1,300
1,625
1,950
2,275
2,600
Ore
Gra
de (A
g)
Copper (%Cu)
Gold (g/t)
Lead (%Pb)
Zinc (%Zn)
Uranium (kg/t U3O8)
Nickel (%Ni)
Diamonds (carats/t)
Silver (g/t)
general trend
(kg/t U3O8)
(Ag, 1884 - 3,506 g/t)
Source: G. Mudd, The sustainability of mining in Australia: Key production trends and their environmental implications for the future, Research Report, October 2007 (http://civil.eng.monash.edu.au/about/staff/muddpersonal/rr5/
Processing Routes for Copper Ores
Ore deposit
Mining
Crushing & grinding
Mineral processing
Smelting
Converting
Refining
Refined metal
Smelting
Pyrometallurgical route
Hydrometallurgical route
In-situ leaching
Leaching (heap, pressure)
Solvent extraction & electrowinning
Refined metal
Crushed/ground ore
Matte
Crushed/ground ore
Concentrate
Matte
LCA Based Energy Consumption - Excludes mining
-
5,000
10,000
15,000
20,000
25,000
Concentrator Smelter Refinery Total
Ener
gy c
onsu
mpt
ion
(MJ/
t Cu) Ore grade 3% Cu
Concentrate recovery 93.7%Smelter recovery 97.1%Overall recovery 90.5%
-
10,000
20,000
30,000
40,000
50,000
Crushing Leach & SX EW TotalEn
ergy
con
sum
ptio
n (M
J/t C
u) Ore grade 2% CuHeap leach recovery 70%SX recovery 93%Overall recovery 64.8%
Concentrate, Smelt, Refine Heap leach, SX, EW
Energy consumption will increase with decreasing ore grade through the concentrator and mining
Energy consumption will increase with decreasing ore grade through leaching and mining
Effect of Ore Grade on Energy Consumption - Pyromet route
0
100
200
300
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5Em
bodi
ed e
nerg
y (M
J/kg
Cu)
Ore grade (% Cu)
Liberation/grain size 75 um
Australia
World
USA
Effect of Ore Grade - Including Mining
0
30
60
90
120
150
0.5% Cu 3.0% Cu
Embo
died
ene
rgy
(MJ/
kg C
u)
RefiningSmeltingMineral processingMining
6 times higher energy consumption for mining and mineral processing
Comparison of Alternative Routes
0
400
800
1200
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Embo
died
ene
rgy
(MJ/
kg C
u)
Ore grade (wt% Cu)
Smelt & conc (75 um)
Smelt & conc (5 um)
Pressure acid leach
In-situ leaching
Heap leaching
Direct smelt
❖ With waste heat recovery from slags, direct smelting becomes even more energy efficient
Presentation by Sharif Jahanshahi PhD, FAusIMM
Sharif Jahanshahi has over 30 years experience in R&D across; high temperature processing of ferrous and base metals, thermodynamics and kinetics of high temperature systems, melt chemistry, process modelling, simulation and development
Currently consulting for leading global players in the metallurgical industry through Meta-Logical Solutions Pty Ltd.
Website: http://www.metalogical.solutionsEmail: [email protected]