A perspective on modelling and simulation

engineering

A perspective on modelling and simulation

engineering

Claudio L. SchneiderClaudio L. Schneider

Coordinator of Mineral Processing - CETEM

Ore body

Mapping

Basic design strategy for

processing plants

Characterization Modeling Scale up Engineering

Unit ops Plant design ResultsOreOre body

Associations

Texture

Mineralogy

Morphology

Drilling

Unit ops Plant design ResultsOre

Simple tests for variability

Complete testing for reference sample scale up

Simulations with parameters obtained from reference sample

Efficiency

Yield

Quality

Investments

Cash Flow

Profit

CAPEX/OPEX

Scale up safety factors

Large volume samples

Variability (geometallurgy)

Processing route

Pilot scale tests

A processing plant at Gaudin’s

time (or thereabouts)

A processing plant at Gaudin’s

time (or thereabouts)

• Units were small. Plants would have several lines of crushing,

grinding and flotation equipment if capacity were to be large.

• The plant would have many sampling points and a laboratory for

routine chemical analysis (sustainability!).

• Crusher and ball mill design would have been made with aid from

Allis Chalmers. CWI and BWI were the basis for conceptual design

and scale-up.

A processing plant at Gaudin’s

time (or thereabouts)

• Flotation conceptual design would be based on batch flotation tests

(Denver cells) and locked-cycle tests.

• Grinding size would have been determined from flotation tests.

• Mineralogy would have been used to qualify concentration

performance. The engineer new there were going to be losses on

coarse unliberated particles that recirculated back to the rougher

cell.

• The regrind circuit would have been the novelty at the time.

(Gaudin?)

A processing plant at Gaudin’s

time (or thereabouts)

• At design time pilot tests were carried out extensively. (certainty)

• At operating time, the discussion would have been this: Is the

regrind circuit working as expected? (Cases of Vale Sossego and

Freeport Indonesia)

• Ball milling is responsible for about 50% of the operating costs.

A modern version of the

processing plant

A modern version of the

processing plant

• Several lines of small units have been replaced by large units and a

single line. CAPEX is reduced. (Kennecott Copperton plant, 1980s)

• The crushing stages and the rod mill were replaced by a large SAG

mill. Major CAPEX gain.

• Fine production in the SAG allows for a smaller grinding circuit

(CAPEX and OPEX reduction)

• VertiMill replaces the ball mill. 25% reduction on energy demand.

A modern version of the

processing plant

• Several lines of small units have been replaced by large units and a

single line. CAPEX is reduced. (Kennecott Copperton plant, 1980s)

• The crushing stages and the rod mill were replaced by a large SAG

mill. Major CAPEX gain.

• Fine production in the SAG allows for a smaller grinding circuit

(CAPEX and OPEX reduction)

• VertiMill replaces the ball mill. 25% reduction on energy demand.

A modern version of the

processing plant

• The regrind circuit is now based on the ISAMill. Finer grinding with

similar energy requirements. Improvement in recovery.

• Column flotation is more efficient in recovering fine particles.

• The ore is tougher, more difficult to liberate and the grade is smaller.

(This is going to get worse, innovation is needed!

A modern version of the

processing plant with HPGR

A modern version of the

processing plant with HPGR

• Secondary crushing is back. (but larger HPGRs are being made)

• Fine generation in the HPGR may reduce ball milling requirements

by 40 % (Cerro Verde reports 20%).

The modern approach for design

• Simulation can be used for processing route evaluation during

conceptual design.

• Usually reduction of OPEX is favored during conceptual desing

while CAPEX is favored during engineering. Are we doing this

right?

• Scale-up technology is available for SAG, HPGR, Ball Mill, VertiMill,• Scale-up technology is available for SAG, HPGR, Ball Mill, VertiMill,

IsaMill and crushers. All comminution operations in a large

processing plant can be scaled-up from bench scale tests, except

for the SAG mill. This is the tendency for the future.

• Automated mineralogy can show us what is really happening in the

plant.

• The regrind circuit now functions according to Gaudin’s design.

Liberation spectra measured on

iron ore (NSPC Steel)

Liberation spectra measured on

iron ore (NSPC Steel)

Automated mineralogy systems

can characterize flotation kinetics

60

70

80

90

100

Ult

ima

te r

eco

ve

ry,

%

212x150

0

10

20

30

40

50

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00

Ult

ima

te r

eco

ve

ry,

%

Average particle grade, %

212x150

150x106

106x75

75x53

53x38

Variability and Geometallurgy have

become a reality when designing a

new plant. (sustainability!)

70%

80%

90%

100%

Cu

mu

lati

ve d

istr

ibu

tio

n,

%

0%

10%

20%

30%

40%

50%

60%

70%

0 5 10 15 20 25 30

Cu

mu

lati

ve d

istr

ibu

tio

n,

%

BWI, kWh/t

Concentration

Processing

Comminution operations

Surface area Exposure Liberation

Concentration processes have natural limitations and

restrictions

even when

liberation is

complete

Leaching applications (and other processes) may be controlled by surface kinetics at one or another stage

Leaching solutions must reach phase of interest and exposure is a fundamental requirement For leaching

applications, liberation and exposure are intimately connected

Required for most mineral processing operations

Bed packing and permeability

Processing

Comminution operations

Surface area Exposure Liberation

• CLP – Confined bed compression• CLP – Confined bed compression

• DWT – Drop Weight Test

• BWI – Ball Work Index

• RWI – Rod Work Index

• CWI – Crusher Work Index

•AI – Abrasion Index

• H-F – Herbst-Fuesternau Batch grinding test

• LABWAL – HPGR testing

• Continuous grinding tests

Comminution operations

Exposure

Liberation

Feed particles

Fixed rollMoving RollOil cylinders

Nitrogen

Cylinders

High pressure grinding rolls: new efficient grinding technology

Product

Comminution operations

LABWAL

Efficient crushing/grinding

Alternative.Alternative.

Comminution operations

DWT

Axb

Crusher ParametersCrusher Parameters

CWI

SAG Milling Parameters

Comminution operations

Grinding Lab

AI

H-FH-F

WI

Comminution operations

Crushing Plant

Pilot scale,

large volumelarge volume

Concentration operations

Flotation

Mini Pilot

Plant, product Plant, product

assessment

Concentration operations

Flotation

2”column

6”column6”column

Concentration operations

Gravity

Jig

SpiralSpiral

Shaking tables

Concentration operations

Magnetic

WHIMS

DrumDrum

RE Drum

Pressure filters

Preparation operations

Large patio for

sample

Handling

sample

receiving ,

preparation

Characterization

Laboratory

• Atomic Force Microscope

• Zeta Sizer

• Tensiometer

• BET

• Goniometer• Goniometer

• FTIR

• Helium Picnometer

• Bubble sizer

• Rheometer

• Leaf Test

• Batch Sedimentation Test

Simulation/model development

Software

ModSim plant-wideModSim plant-wide

simulator