peter jansson - outotec (usa) inc - iron ore tailings reprocessing to maximize ore production

Iron Ore Tailings Reprocessing to Maximize Ore Production

America Iron Ore Conference 2014

© Outotec – All rights reserved

Overview

Why the need for tailing

processing?

Decreasing Fe grade of Iron ore reserves

Need for sophistication of processing plants due to

inter-grown ore bodies

Increase in demand of iron

ore incoherence

with increase in steel demand

The Fe content of the tailings

varies and reaches more than 55% Fe in

some Asian regions

Valuable mineral in

tailings dumps due to lack of

suitable processing

11/17/2014 2 America Iron Ore 2014 | Peter Jansson


Outotec’s Focus

• Minimize tailing production.

• Improvement of existing processing plants.

• Sustainable operation by optimized tailing disposal and water

recovery management.

• Re-processing tailings resulting from former operations.

• Beneficiation using modular units consisting of SLon in series with

desliming, WLIMS or gravity separation

11/17/2014 America Iron Ore 2014 | Peter Jansson 3


Working Principle of Outotec SLon High Gradient Magnetic Separator Vertical carousel

• Mag flushing in opposite direction of feed

• Mags are not washed through the matrix

• Reduced matrix plugging

Pulsation Bath

• Reduce particle momentum

• Minimize entrapment

Rod Matrix

• High magnetic force while minimizing entrapment of particles

• Ensure all particles see high gradient zones



Working Principle of Outotec SLon High Gradient Magnetic Separator



PROCESS DEVELOPMENT TESTING ON TAILING SAMPLES FROM OPERATIONS

WORLDWIDE



COMPANHIA SIDERURGICA NACIONAL (CSN) - BRAZIL • (CSN) is the second major

steel-maker company in Brazil

• Flotation rejects and thickener underflow tested using SLon lab unit for plant optimization

• Slon recoveried upto 66.6% Fe from flotation rejects and upto 59.9% Fe from thickener underflow

• Increase in magnetic field intensity increased in iron recovery but also increase in SiO2, Al2O3 and Mn which reduced Fe grade


0

10

20

30

40

50

60

70

62

62.5

63

63.5

64

64.5

65

65.5

66

66.5

0 0.2 0.4 0.6 0.8 1 1.2

Fe R

eco

very

(%

)

Fe G

rad

e (

%)

Magnetic Intensity (Tesla)

Fe Grade (%)Flotation Rejects

Fe Grade (%) Slimes

Fe Recovery (%)Flotation Rejects

Fe Recovery (%)Slimes


SAMARCO MINERACAO – BRAZIL SLON 100 TESTING

• Feasibility testing was done on flotation tailing sample with 6 to 7 % iron.

• Test showed the increase in recovery of Fe content in magnetic fraction with increase in magnetic field from 0.15 to 0.5 t

• Screening of feed before the SLon feed showing a big improvement removing the coarse silica.

Test # Products Test

Conditions

Mass % Fe Assay Fe

Recovery

1 Mag 0.5 Tesla

Pulsation

240

21.82 33.81 78.46

N-mag 78.18 2.59 21.54

2 Mag 0.3 Tesla

Pulsation

240

17.80 36.40 67.00

N-mag 82.20 3.88 33.00

3 Mag 0.15 Tesla

Pulsation

240

10.54 40.78 44.45

N-mag 89.45 6.00 55.55

The coarse particle (+150 mesh) were removed by screening. 47.73% by weight -

150 mesh.

4 Mag 0.5 Tesla

Pulsation

240

27.14 47.68 79.70

N-mag 72.86 4.52 20.30

The coarse particle (+200 mesh) were removed by screening. 32.02% by weight -

200 mesh.

5 Mag 0.5 Tesla

Pulsation

240

34.12 55.27 82.35

N-mag 65.88 6.13 17.65



SAMARCO MINERACAO – BRAZIL PILOT SCALE TESTING WITH SLON 500


• Increase in Fe receovery with

increase in magnetic field.

• Fe grades increases till 0.48 T

with maximum grade of approx

34% with 82% iron recovery

• Silica recovery increases with the

magnetic field too but the rate of

increase is very low from 0.29T

to 0.48T


BUCHANAN IRON ORE– SOUTH AFRICA SLON 100 TESTING

•Tailing sample with 48.9% Fe.

•Screened at 250um to remove

oversize resulting in minor iron losses

of 0.8%

•Pre-treated using LIMS to remove

magnetite form the sample

•Operating variables

magnetic intensity (0.1 – 1.0T)

pulsating frequency (0-300

ppm)

matrix size (1, 1.5, 2, 3 and

4mm).

•A combined concentrate grading 66%

iron could be achieved at recoveries of

60% to 75%.




•Tailing sample with 47% Fe.

•Screened at 250um ( minor iron

losses of 1.4%)

•Pre-treated using LIMS to remove

magnetite form the sample


magnetic intensity (0.1 – 1.0T)

pulsating frequency (0-300

ppm)

matrix size (1, 1.5, 2, 3 and

4mm).

•A combined concentrate grading 63%

to 64% iron at a recovery of 50% to

66%




•The two composites were combined

and screened at 250 micron and pre-

treated using LIMS


magnetic intensity (1.0T)

pulsating frequency (200 - 300

ppm)

matrix size (1.5 mm).

% Solids ( 12% & 21%)

•Lower solids content in feed and 250

rpm of pulsating frequency were

chosen with Fe grade of 65.5 % at a

recovery of 77.7 %.



BUCHANAN IRON ORE– SOUTH AFRICA SLON 750 TESTING MASS BALANCING



MIKHAILOVSKY GOK(MGOK) – RUSSIA SLON 100 TESTING

Test # Products Test

Conditions

Mass % Fe Grade % Fe

Recovery

1

LIMS Mags

0.5 Tesla

Pulsation

220

21.52 57.78 30.58

SLon Mags 41.82 50.01 51.43

LIMS+SLon

Mags 63.34 52.65 82.01

Nonmags 36.66 19.96 17.99

Feed 100.00 40.67 100.00

2

LIMS Mags

0.3 Tesla

Pulsation

220

20.72 57.78 29.66

SLon Mags 32.70 51.84 42.00

LIMS+SLon

Mags 53.42 54.14 71.66

Nonmags 46.58 24.55 28.34

Feed 100.00 40.36 100.00

3

LIMS Mags

0.3 Tesla

Pulsation

250

22.03 57.78 31.51

SLon Mags 29.34 52.69 38.27

LIMS+SLon

Mags 51.37 54.88 69.78

Nonmags 48.63 25.13 30.22

Feed 100.00 40.40 100.00

• Testing of Mikhailovsky iron ore

sample containing 40.36% iron

using SLon 100 and 900 Gauss

LIMS.

• Magnetic separation effectively

produced maximum grade of

54.88% Fe with 69.78%

recovery




• Testing of sample with 40.3% Fe

and 39.6% SiO2 using SLon 500 in

series with 1000 Gauss LIMS

• Pre-treatment : Grinding using rod

mill to reduce the sample size from

100% of -5mm to P80% of 82

microns (labeled as Sample II)

• A combined concentrate grading

53.2% Fe with 85.2% recovery.

Test Products Test

Conditions

Mass % Fe Grade

%

Fe

Recovery

%

Sample II

LIMS+SL

on Mags

0.5T

Pulsation

stroke: 20

mm,

Pulsation:

250,

Ring

speed:

2.5 rpm.

64.62

53.2

85.2

Non-

mags 35.38

16.7

14.8

Feed 100.0 40.3 100




•The magnetic separation feed

of the sample-I have a coarser

grinding fineness than the test

feed of sample II.

•Finer grinding enabled higher

grade and recovery.

•Magnetic concentrate was then

tested for flotation circuit for

further upgradation.



LONDON MINING – SIERRA LEONE (MARAMPA IRON ORE TAILINGS) SLON 100 TESTING

•Flowsheet designing for Phase 1a,1.8 Mt/a tailing processing plant

using a two stage SLon magnetic separation circuit

Testing for Rougher Circuit

• Operating conditions : - Matrix – 2mm, 3mm - Pulsation frequency (200, 250 or 300 ppm) - Magnetic field (0.5, 0.6, 0.7 and 0.8 Tesla)

• Optimum conditions were 0.6 Tesla utilizing 3 mm rod matrix at 300ppm

Testing for Cleaner Circuit

• Same operating conditions as rougher

• Optimum conditions were 0.35 T, 3 mm matrix at 300ppm

• Cleaner tailings at 12.1% of head feed with 47% Fe were used for Scavenger testing

Testing for Scavenger Circuit

• Optimum conditions produced concentrate weighing 7 to 8% of the head feed at 63.7% Fe grade and 76.5% Fe recovery.

Conc. Tails



LONDON MINING – SIERRA LEONE (MARAMPA IRON ORE TAILINGS) SLON 100 TESTING

Sample Fe Fe2O3 SiO2 Al2O3 MgO CaO Na2O K2O TiO2 MnO P2O5 Cr2O3

Rougher

SLon Feed

22.0 31.4 54.1 8.46 0.64 0.09 0.02 0.2 0.17 0.88 0.09 0.03

Cleaner

SLon

Concentrate

66.1 94.4 1.74 1.09 0.15 0.07 0.02 0.14 0.35 1.37 0.05 0.03

Scavenger

SLon

Concentrate

63.7 91.0 3.05 1.86 0.26 0.11 0.04 0.30 0.34 1.73 0.06 0.03

Final

Estimated

Concentrate

65.5 93.5 2.08 1.29 0.18 0.08 0.03 0.18 0.35 1.46 0.05 0.03



LONDON MINING – SIERRA LEONE (MARAMPA IRON ORE TAILINGS) SLON 750 PILOT TESTING

•100 kg (-1mm) subsample was

subjected to rougher – cleaner circuit

lock cycle testing (seven cycles)

•Rougher conditions were 0.6 T, 3 mm

matrix, 300 ppm & 169 kg/h feed rate.

•Cleaner conditions were 0.35 T, 3 mm

matrix, 300 ppm & 87 kg/h feed rate.

•The cleaner stage tailings from

previous cycle were proportionally

added to the next cycle’s rougher feed.

• The results showed the process

stability.

London Mining - Marampa Tailings Lock Cycle Testing

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 6 Cycle 7%

RO wt%

CL wt%

RO Fe

CL Fe

RO SiO2+Al2O3

CL SiO2+Al2O3



LONDON MINING – SIERRA LEONE (MARAMPA IRON ORE TAILINGS) PLANT

• London Mining currently has two processing plants which operate a

total of 22 SLon 2500 units.

• Both plants are identical and have a rougher/cleaner WHIMS circuit.

• Feed which is a mixture of old tailings and weathered ore (20 – 25 %

Fe) is screened at 1mm prior to SLon processing.

• The Rougher Stage design throughput capacity is 875 T/Hr/Plant (7

SLon 2500 units) at 40% solids.

• The Cleaner Stage design throughput capacity is 360 T/Hr/Plant (4

Slon 2500 units) at 21% solids.

• Product grade produced – 65.0% Fe



IRON ORE TAILING PROCESSING PLANT – USA SLON 100 TESTING

• The testing was done for facility that extracts and processes iron-

bearing tailings leftover from previous iron mining operations

• Slon 100 testing parameters feed charge (200g and 270g)

matrix rod size (1.5, 2 and 3mm)

pulsation frequency (200 or 300 ppm)

magnetic intensity (0.6, 0.8 and 1T)

• At the conditions evaluated, the SLon recovered from 54 to 81% of

the iron from tails at grades ranging from 61% to 52% Fe.

• SLon 2500 and SLon 2000 has been installed in Rougher – Cleaner

circuit respectively for processing the tailing from upstream

processing circuit processes the mined leftover tailings.



TESTING CONCLUSION

• Research is being conducted to enhance iron recovery from a tailing

stream containing hematite using gravity, magnetic and flotation

separation techniques

• Outotec’s SLon VPHIMS proved to be effective in recovering Iron

from various tailing samples around the world with Iron grade

ranging from 6% all way to 48%

• In some cases, Fe grades were improved with pre-processing

consisting of de-sliming, LIMS or post processing consisting of

flotation.

• Implementation of SLon in tailing beneficiation will: Increase iron ore production

Increase the life of tailing sumps

Increase the life of current reserves by optimizing the tailing processing

circuit


peter jansson - outotec (usa) inc - iron ore tailings reprocessing to maximize ore production

News & Politics

iron ore tailings

demand of iron ore incoherence

recovery of fe content

um minor iron losses

fe receovery

fe grades

slon feed

rights reservedoverviewwhy