David Hatton

7/27/2019 David Hatton

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Does size matter?

How do you predict the flotation response of a circuit

due to a change in feed grind?


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Does size matter?

How do you predict the flotation response of a circuit

due to a change in feed grind?

From a flotation test:

SGSs Mineral Flotation Test (MFT)

And a plant survey

For circuit calibration in IGS

(Copies available at the SGS booth)


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The Theory: Flotation by size

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Particle size (um)

FloatablePercentageofCopper


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Theory: Grind size distribution

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Particle size (um)

CummulativePer

centPassing


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Particle size (um)


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Particle size (um)

CummulativePerc

entPassing


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Particle size (um)


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Particle size (um)

CummulativePerc

entPassing

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P80 (um)

FloatablePerce

ntageofCopper


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Particle size (um)


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P80 (um)

FloatablePerce

ntageofCopper

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Particle size (um)

CummulativePerc

entPassing


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Particle size (um)

CummulativePerc

entPassing

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P80 (um)



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Particle size (um)


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Particle size (um)

CummulativePer

centPassing

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P80 (um)

FloatablePerce

ntageofCopper


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Particle size (um)


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Particle size (um)

CummulativePercentPassing

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Particle size (um)


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CummulativePerc

entPassing

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P80 (um)

FloatablePercentag

eofCopper


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CummulativePerc

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What is the difference?

Individual Particles Overall Distribution

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0 50 100 150 200 250 300Particle size (um)


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Floatable percentage by size

SGS Laboratory Flotation Test, the MFT

Froth crowder and high scraping rate high froth recovery

Extended residence to recover all floatable material

Size concentrates are collected

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Particle size (um)



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CopperRe

covery

Overall recovery by size Includes entrainment

Entrainment Total Recovery


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Particle size (um)

CopperRe

covery

Recovery by size Includes entrainment

Entrainment

Floatable

Proportion


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Particle size distribution

Grinding Simulations

Rossin-Rammler fitted to obtain P80, m

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Particle size (um)

Cummu

lativePercentPassing

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80P

x6094.1exp100100xP


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Validation

MFTs were conducted at a P80 of 180 m

From these the floatable proportion was calculated

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Grind P80 [um]

FloatableCudeviation(%)

T1 measured T7 measured T10 measured


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Validation

From the procedure the floatable proportion was

predicted at a range of P80s

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Grind P80 [um]


T1 predicted T1 measured T7 predicted

T7 measured T10 predicted T10 measured


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Validation MFTs were also conducted at P80s of 90, 130 and 240 m

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Grind P80 [um]


T1 measured T7 measured T10 measured


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Validation MFTs were then conducted at P80s of 90, 130 and 240 m

The results confirmed the predictions

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Grind P80 [um]


T1 predicted T1 measured T7 predicted

T7 measured T10 predicted T10 measured


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Circuit Simulations

A flotation circuit was calibrated in IGS from MFTs

conducted on the plant feed and from plant survey data

At the target concentrate grade simulations predicted a

3% increase in recovery from a 50 m finer grind


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Plant Trial

Plant surveys were done at baseline conditions

Plant tonnage reduced by 30% to achieve 50 m finer

grind

Plant surveyed at finer grind

Equal flotation residence time in both surveys

Surveys mass balanced and compared

Final concentrate grade differed between baseline and

finer grind surveys

Change in grade was corrected for by trade-off

simulations (in IGS) to obtain the actual change in

recovery


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Results

The predictions were accurate (within 0.2% recovery)

The MFT thus provides a cost effective method for predicting the

change in plant performance with change in grind

Recovery GradeDifference Difference

Simulations based on MFTs 3.0% -0.2%

Plant Trial 4.5% -4.6%

Grade adjusted Plant Trial 3.2% 0.0%

Evaluation Method

Documents

David Hatton