Wenying Liu

7/30/2019 Wenying Liu

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Effect of Bacteria on the Flotation

of Chalcopyrite

Wenying Liu

Centre for Water in the Minerals Industry

Sustainable Minerals Institute

The University of Queensland, Australia



Water Challenges

Water reuseMultiple sources

Water Scarcity

Climate Variability

Water Challenges Resulting ProblemGood Water Management

Sustainability Goal

Water Competition

Community Concern

Variation



Causes of Water Quality Variation

External Sources• Multiple sources of raw water

• External water reuse

• Climate conditions

Internal Sources• Ore

• Reagent

• Internal water reuse

A Simplified View of Mine Site Water System

Ore & ReagentInternal

Raw Water

Tailings

Facility

External Reuse

External

Worked

WaterInternal Reuse

Concentrator



Water Constituents

Abiotic

• Meaning not alive – metal ions

Biotic

• Meaning of or related to life – organics,microorganisms



Impact of Abiotic on Flotation

Negative Impacts

• Metal hydroxide – forming a barrier for collector

adsorption(Hoover 1980; Rao & Finch 1989)

• Salt - Formation of finer gas bubbles

(Pugh et al. 1997)



Biological Processes in Mineral Processing

• Bioreagent

(Somasundaran et al, 1998; Nagaoka et al., 1999)

Importance of Bacteria in Conventional Flotation

Impact of Biotic on Flotation

(Levay and Schumann, 2006)

• Multiple water sources containing bacteria

(Slatter et al., 2009)



Objectives of This Research: Biotic

Bacteria – E. coli Mineral - Chalcopyrite

Quantify effect of bacteria on mineral flotation

Flotation



Microflotation Experiment

Experimental Setup



r i t e F l o t a t i o n

Y i e l d ,

%

40

60

80

100

Baseline Test

Flotation without E. coli

Collector (Sodium Ethyl Xanthate), mg/L

0.0 0.2 0.4 0.6 0.8 1.0 1.2

C h a l c o p

y

0

20

Figure 1 Chalcopyrite flotation yield as a function of collector

concentration in the absence of E. coli



i t e F l o t a t i o n Y i e l d ,

%

40

60

80

100

Experimental Results

Flotation with E. coli

Initial E. coli Concentration, cell / ml

105 106 107 108 109

C h a l c o p

y

0

20

Figure 2 Effect of E. coli cell concentration on the flotation of chalcopyrite



r i t e F l o t a t i o n

Y i e l d ,

%

40

60

80

100


Flotation with Salt

NaCl Concentration, mg/L

0 1000 2000 3000 4000

C h a l c o p y

0

20

Figure 3 Chalcopyrite flotation yield as a function of NaCl

concentration in the absence of E. coli




%

40

60

80

100No NaCl

NaCl Concentration: 696 mg/L




Flotation with Salt and E. coli

E. coli Concentration, cell / ml

106 107 108 109

C h a l c o p

y r

0

20

Figure 4 Effect of E. coli cell concentration on the flotation

of chalcopyrite at different NaCl concentrations




%

40

60

80

100

No Collector

0.3 mg/L

0.6 mg/L

1 mg/L


Increase Collector Concentration

Initial E. coli Concentration, cell/ml

106 107 108 109

C h a l c o p

y r

0

20

Figure 5 Effect of E. coli cell concentration on the flotation

of chalcopyrite at different collector concentrations



Conclusions

E. coli had an adverse effect on chalcopyrite flotation;

More pronounced effect in the presence of NaCl;

Increasing collector concentration could only partially

miti ate the adverse effect.



Acknowledgement

My supervisors Chris Moran, Sue Vink and Yongjun Peng

Staff and students in Sustainable Minerals Institute

ARC Linkage and AMIRA P260E

Scholarship from the University of Queensland, Australia



Thank you

Questions?

Wenying Liu

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