Flotation Chemistry of Complex Sulphide Ores: Recycling of Process Water and Flotation Selectivity. Fatai Kolawole Ikumapayi

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1 Flotation Chemistry of Complex Sulphide Ores: Recycling of Process Water and Flotation Selectivity Fatai Kolawole Ikumapayi

, 2007) and it requiresbillions of gallons of water in the process Recycling of flotation

2 Introduction Froth flotation method is used annually to concentrate more than one billion tons of global sulphide ores (Fuerstenau et al., 2007) and it requiresbillions of gallons of water in the process Recycling of flotation effluents through the ore processing plant is one of the ways of reducing both plant-operating costs and industrial impact onto the local ecosystem

3 Background Recycled water in sulphide mineral processing plants have shown various effects in the recovery of sulphide minerals A number of major and minor species exists as components of recycled water these includes: Ca 2+,SO 4 2-, SO 3 2-,S 2 O 3 2-,S 4 O 6 2- etc, rest flotation reagents, traces of some transition metals and a number of microorganisms

4 AIM To establish the effects of two major species of Ca 2+ and SO 4 2- on the flotation of sulphide minerals

5 Materials and methods Pure Chalcopyrite, Galena, Sphalerite and Pyrite from various sources Complex sulphide ores from Boliden Renström and Kristineberg mines Deionised, process and tapwater Hallimond flotation Zeta-potential measurements Diffuse reflectance FTIR spectroscopy measurements XPS measurements Bench-scale flotation of sulphide ore

6 Hallimond flotation

7 Zeta-potential measurements

8 DRIFT-FTIR spectroscopy

9 XPS-spectroscopy

10 Bench-scale flotation

11 Results and discussions

12 Hallimond flotation results 100 Combined effect of calcium and sulphate on CuFeS 2 flotation Recovery % CuFeS 2 Deionised Water CuFeS 2 Process Water Concentration of sulphate (mg/l) Concentration of calcium (mg/l)

13 Hallimond flotation contd. Combined effect of calcium and sulphate on FeS 2 flotation Recovery % FeS 2 Deionised Water FeS 2 Process Water Concentrations of sulphate (mg/l) Concentrations of calcium (mg/l)

14 Zeta-potential mv Zeta-potential ph CuFeS2 CuFeS2 in PW 200 ppm Ca 500 ppm Ca 1000ppm Ca

15 Zeta-potential contd. 30 Zeta potential mv ph ppm Ca 500 ppm Ca 1000ppm Ca FeS2 FeS2 in PW

16 DRIFT-FTIR Contd. Effect of Ca 2+ and SO 4 2- in adsorption of xanthate on chalcopyrite in deionised water

17 Bench-scale flotation Renström ore Kristineberg ore Tapwater Process water Tapwater Process water Recovery % 22.5 o C Cu Pb Zn o C Cu Pb Zn o C Cu Pb Zn

18 Conclusions Calcium and sulphate ions have significant depressing effect on chalcopyrite and activating effects on pyrite in Hallimond flotation Singnificant effect of calcium and not sulphate ions are seen on the zeta-potential of all the minerals FTIR and XPS shows that the minerals contains oxidised surface species which are mostly removed by xanthates Bench scale flotations shows that recovery decreases with temperature,better recovery in process water, Reduced calcium concentration and increased sulphate concentration in the final pulp water

19 Acknowledgement Prof. Jan Rosenkranz (Chair Prof. of mineral processing Ltu) Prof. Kota Hanumantha Rao (Main supervisor), Björn Johansson (co-supervisor Boliden mineral AB), Assoc. Prof. Allan Holmgren (co-supervisor Ltu) Andreas Berggren (Manager process technology Boliden AB) Prof. Oleg Antzutkin (chairman ARC-MMS) Utmost thanks to everyone present here today, great appreciation to you for your precious time The financial support from the Swedish VINNOVA foundation and, Boliden and Lundin Mining mineral companies for the research project on Recycling of process water and influence of its chemistry on sulphide flotation and flotation selectivity is gratefully acknowledged Finally Bergforsk (Rocktechcentre) for recognition of this work by giving the award

20 Thanks for listening Questions?

21 Chemical species and their composition range in Boliden process water Concentration range of chemical species in process water Species Concentrations From To Unit Sulphate SO mg/l Calcium Ca mg/l Iron Fe mg/l COD (Cr) < mg/l Nitrogen N mg/l Phosphorus P < mg/l Magnesium Mg mg/l Manganese Mn µg/l Zinc Zn µg/l Aluminium Al µg/l Cadmium Cd µg/l Cobolt Co µg/l Copper Cu µg/l Mercury Hg <0.1 <0.13 µg/l Conductivity at 25 o C ms/m

22 Zeta-potential contd. 20 Concentrati on of sulphate mg/l Z eta- poten ti a l m V 10 Concen ration of calcium mg/l Zeta p otential mv chal copyrite pyri te sphalerite galena chalcopyri te pyrite sphal eri te gal ena

23 DRIFT-FTIR Oxidation of minerals in H 2 O 2

24 DRIFT-FTIR Contd. Effect of Ca 2+ on chalcopyrite in process water

25 DRIFT-FTIR Contd. Effect of Ca 2+ on pyrite in process water

26 Future work Effects of other minor species in process water, such as reduced sulphur compounds (RSC) (sulfoxyanions with sulphur in the oxidation state below VI), on sulphides flotation by adsorption, zeta-potential, FTIR and XPS measurements Find and adopt best chemical recourses to overcome the detrimental effects of the process water components Pilot flotation studies based on the new chemical recourses

27 Experimental Design of in situ FTIR

AGRICOLA RESEARCH CENTRE: INTERACTIONS IN MULTI-COMPONENT MINERAL SYSTEMS (ARC-MMS)

AGRICOLA RESEARCH CENTRE: INTERACTIONS IN MULTI-COMPONENT MINERAL SYSTEMS (ARC-MMS) Oleg N. Antzutkin 1, Hanumantha Rao 1, Fatai Ikumapai 1, Allan Holmgren 1, Lars Gunneriusson 1, Björn Johansson 2, Andreas