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21. Farinato, R.S. and Nagaraj, D.R., Larkin, P., Lucas, J., and

Brinen, J. S., “Spectroscopic, Flotation and Wettability Studies of

Alkyl and Allyl Thionocarbamates”, SME-AIME Annual Meeting,

Reno, NV, Preprint 93-168, Feb. 1993.

22. Gorken, A., Nagaraj, D. R. and Riccio, P. J., “The Influence Of

Pulp Redox Potentials And Modifiers In Complex Sulfide

Flotation With Dithiophosphinates”, Proc. Symp. Electrochemistry

in Mineral and Metals Processing, The Electrochemical Society,

Princeton, Proceedings Vol. 92-17, pp. 95-107, 1992.

23. Brinen, J. S., Greenhouse, S. Nagaraj, D. R. and Lee, J., “SIMS

and SIMS Imaging Studies Of Dialkyl Dithiophosphinate

Adsorption On Lead Sulfide”, Int. J. Miner. Process. Vol. 38,

pp. 93-109, 1993.

24. Basilio, C. I., Kim, D. S., Yoon, R.-H., Leppinen, J. O. and Nagaraj,

D. R., "Interaction of Thiophosphinates with Precious Metals",

SME-AIME Annual Meeting, Phoenix, AZ, Preprint 92-174,

Feb. 1992.

25. Farinato, R. S. and Nagaraj, D. R., “Time Dependent Wettability

Of Metal And Mineral Surfaces In The Presence Of Dialkyl

Dithiophosphinate”, Presented at ACS Symposium on Contact

Angle, Wettability and Adhesion, J. Adhesion Sci. Technol.

Vol. 6, No. 12, pp. 1331-46, April 1992.

26. Basilio, C. I., Kim, D. S., Yoon, R.-H. and Nagaraj, D.R., “Studies

On The Use Of Monothiophosphates for Precious Metals

Flotation”, Minerals Engineering, Vol. 5, No. 3-5, 1992.

27. Yoon, R.-H., Nagaraj, D. R., Wang, S. S. and Hildebrand, T. M.,

“Beneficiation of Kaolin Clay by Froth Flotation Using Alkyl

Hydroxamate Collectors”, Minerals Engineering, Vol. 5, No. 3-5,

1992.

28. Basilio, C. I., Yoon, R.-H., Nagaraj, D. R. and Lee, J. S. , “The

Adsorption Mechanism of Modified Thiol-type Collectors”,

SME-AIME Annual Meeting, Denver, CO, Feb. 1991, Preprint

91-171.

29. Nagaraj, D.R., Brinen, J. S., Farinato, R.S. and Lee, J. S.,

“Electrochemical and Spectroscopic Studies of the Interactions

between Monothiophosphates and Noble Metals”, 8th Intl.

Symp. Surfactants in Solution, Univ. Florida, 1990; Pub. in

Langmuir, Vol. 8, No. 8, pp. 1943-49, 1992.

Flotation reagent fundamentals

30. Nagaraj, D.R. et. al., “Interfacial and Bulk Aqueous Phase

Processes In The System Salicylaldoxime- CuO - Water”,

Accepted for Pub. in Colloids and Surfaces, 1996.

31. Nagaraj, D. R. and Gorken, A., “Potential Controlled Flotation

And Depression Of Copper Sulfides And Oxides Using

Hydrosulfide In Non-Xanthate Systems”, Can. Met. Quart.,

Vol. 30, No. 2, pp. 79-86, 1991.

32. Nagaraj, D.R. et. al., “The Chemistry And Structure-Activity

Relationships For New Sulfide Collectors”, Processing of Complex

Ores, Pergamon Press, Toronto, 1989, p. 157.

33. Nagaraj, D.R., Lewellyn, M. E., Wang, S. S., Mingione, P. A. and

Scanlon, M. J., “New Sulfide and Precious Metals Collectors: For

Acid, Neutral and Mildly Alkaline Circuits”, Developments in

Minerals Processing, Vol. 10B, Elsevier, pp. 1221-31, 1988.

34. Basilio, C. I. Leppinen, J. O., Yoon, R.-H., Nagaraj, D.R. and

Wang, S. S., “Flotation and Adsorption Studies of Modified

Thionocarbamates on Sulfide Minerals”, SME-AIME Annual

Meeting, Phoenix, AZ, Preprint 88-156, Feb. 1988.

35. Nagaraj, D.R., “The Chemistry and Applications of Chelating

or Complexing Agents in Mineral separations”, Chapter in:

Reagents in Mineral Technology, Marcel Dekker, New York,

Chapter 9, pp. 257-334, 1987.

36. Nagaraj, D.R. and Avotins, P. V., “Development of New Sulfide

and Precious Metals Collectors”, In: Proc. Int. Minerals Process.

Symp., Turkey, pp. 399, Oct. 1988.

37 Nagaraj, D. R., Rothenberg, A. S., Lipp, D.W. and Panzer, H. P.,

“Low Molecular Weight Polyacrylamide-based Polymers as

Modifiers in Phosphate Beneficiation”, Int. J. Miner. Proc. 20,

pp. 291-308, 1987.

38. Nagaraj, D.R., Wang, S. S, Avotins, P. V. and Dowling, E.,

“Structure - Activity Relationships for Copper Depressants”,

in Trans. IMM, Vol. 95, pp. C17-26, March 1986.

39. Nagaraj, D.R., Wang, S. S. and Frattaroli, D. R., “Flotation of

Copper Sulfide Minerals and Pyrite with New and Existing

Sulfur-Containing Collectors”, Metallurgy, Vol. 4, Pub. 13th

CMMI Congress and The Australasian Inst. Min. Met., Australia,

pp. 49-57, May 1986.

Mining Chemicals Handbook

100

40. P. Somasundaran and Nagaraj, D. R., “The Chemistry and

Applications of Chelating Agents in Flotation and Flocculation”,

Reagents in the Minerals Industry, Eds. M.J. Jones & R. Oblatt, The

Inst. Min. Met., London, pp. 209-219, 1984.

41. Nagaraj, D. R., “Partitioning of Oximes into Bulk and Surface

Chelates in the Hydroxyoxime - Tenorite System”, The 111th

Annual SME/AIME Meeting, Dallas, Feb 1982.

42. Nagaraj, D.R. and Somasundaran, P., “Chelating Agents as

Collectors in Flotation: Oxime - Copper Minerals Systems”,

Min. Eng., pp. 1351-57, Sept. 1981.

43. Nagaraj, D.R. and Somasundaran, P., “Commercial Chelating

Extractants as Collectors: Flotation of Copper Minerals Using

LIX Reagents”, Trans. SME., Vol. 266, pp. 1892-98.

44. Nagaraj, D.R. and Somasundaran, P., “Chelating Agents as

Flotaids : LIX - Copper Minerals Systems”, Recent Developments

in Separation Science, CRC Press, Vol. V.

Flotation reagent fundamentals

101

Mining Chemicals Handbook

102

FLOTATION OF SULFIDE ORES

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Section 6 Flotation of sulfide ores

Many collectors and frothers are in use in the flotation treatment of

sulfide and metallic ores containing such metals as copper, lead,

zinc, nickel, cobalt, molybdenum, iron, precious metals (including

platinum-group metals) and such penalty elements as arsenic, anti-

mony and bismuth. The principal factors affecting the choice of

collectors are the mineral forms (sulfide, oxidized and/or metallic

species) and their associations with each other and the gangue

minerals.

Recent trends in flotation practice have shown that, in many cases,

a combination of two or more different collectors provides better

metallurgy than a single collector. This is not surprising when one

considers that, even in such a simple case as copper ores, there may

be a variety of copper minerals present (eg. chalcopyrite, chalcocite,

covellite, bornite, native copper, tetrahedrite, and oxidized or

tarnished copper minerals) each of which responds differently to

different collector chemistries. Obviously, this aspect is even more

important when making a bulk float of minerals of two different

metals (eg. lead and copper). For many decades, the most commonly-

used collector combinations were those of xanthate and dithiophos-

phate, or of xanthate and dialkyl thionocarbamate. However, in the

past 10-15 years, a large number of new collector chemistries has

been developed and introduced by Cytec. Whilst increasing the

complexity of the reagent testing process, this has undoubtedly

greatly expanded the opportunity of establishing the optimum

reagent combination for any specific ore. This aspect of collector

selection is addressed in more detail in Section 6.4.

6.1 Cytec’s sulfide collectors (promoters)

There are many possible ways of categorizing sulfide collectors; eg.

copper collectors, lead collectors, soluble collectors, oily collectors,

thiol collectors, etc. We feel that none of these classifications

adequately distinguishes the actual functionality of the collectors.

Consequently we have chosen to classify the collectors based on

their chemical structure, functional groups, and the important

donor atoms. Please note that Cytec has always used the terms

"collector" and "promoter" synonymously. Other reagents which

assist the adsorption of a collector on the mineral surface are

referred to as "activators", and their use is discussed later.

Flotation of sulfide ores

105

6.1.1 AERO xanthates

Xanthate collectors were introduced in 1925, and are still widely

used, especially for easy-to-treat ores where selectivity (especially

against iron sulfides and penalty elements) is not an issue. They are

usually supplied in the powder or pellet forms and are readily

soluble in water, and could be made up to any strength for conven-

ience in dosing. Xanthate solutions have relatively poor long-term

stability and, therefore, are supplied in liquid form only when the

manufacturing plant is in close proximity to the use location.

Xanthates are available in a range of carbon chain lengths, generally

from C

to C

. The collecting power generally increases with

increase in chain length, but the selectivity decreases. Xanthates are

relatively unstable at low pH and, therefore, are not suitable for

flotation in acid circuits.

AAEERROO 330033 xxaanntthhaattee

– Potassium ethyl xanthate. Shortest carbon

chain of the available AERO xanthates. Particularly useful where

maximum selectivity is desired.

AAEERROO 332255 xxaanntthhaattee

– Sodium ethyl. Used on complex ores for

maximum selectivity. Most frequently used to float galena with

Pb/Zn ores.

AAEERROO 334433 xxaanntthhaattee

– Sodium isopropyl. Most widely used in the

flotation of sulfide minerals of copper, molybdenum and zinc.

Good compromise between collecting power and selectivity.

AAEERROO 331177 xxaanntthhaattee

– Sodium isobutyl. A relatively strong collector

used in the flotation of Cu, Pb, Ni, Zn, and PGM ores.

AAEERROO 335500 xxaanntthhaattee

– Potassium amyl. The most powerful and least

selective xanthate. Often used as a scavenger collector following a

more selective rougher collector. Used widely in the flotation of

Cu, Ni, Zn, and Au-containing iron sulfides.

6.1.2 Xanthate derivatives

Two classes of xanthate derivatives are in common use, xanthogen

formates and xanthate allyl esters. Both are oily collectors, more

xanthate

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106

selective than the corresponding xanthate, and can be used over a

wide pH range. Since they are insoluble in water, point of addition

and conditioning time may be important. Xanthate allyl esters are

among the most selective of all the available sulfide collectors.

AERO 3302 promoter

Comments

• Oily collector, not soluble in water, therefore, usually fed to

grinding mill.

• Effective copper collector in both alkaline and acid circuit. Also

good for zinc flotation in lime circuit. Usually used in conjunction

with xanthate. Very selective against pyrite.

• Excellent collector for molybdenite and is, therefore, often used

on copper/molybdenite ores.

• Often increases recovery of gold and silver.

• Used for flotation of sulfidized copper-oxide minerals.

• Improves selective recovery of platinum group metals.

AERO 203, 204, and 758 promoters

NNoottee::

In some regional markets, these products are known as

SF 203, 204, and 758 promoters.

Comments

• Oily collector, not soluble in water, therefore, usually fed to

grinding mill.

Flotation of sulfide ores

107

Dialkyl Xanthogen Formate

Xanthate Allyl Ester

• Originally developed specifically for flotation of copper ores in

acid circuits (pH 3-5). They are now used in both acid and

alkaline circuits for copper-molybdenum ores, and in alkaline

Zn circuits.

• In alkaline circuits, they are more selective than their

corresponding xanthates.

•

AAEERROO 220044

promoter is a stronger collector than AERO 203

promoter, and is often used to improve coarse particle recovery.

•

AAEERROO 775588

promoter is a formulated product that is designed to

improve flotation kinetics and froth characteristics/properties.

6.1.3 Phosphorous-based collectors

A. Aryl AEROFLOAT and AERO promoters

A.1 Dithiophosphates

AAEERROOFFLLOOAATT 2255 pprroommootteerr

– Acid form. Good for Ag, Pb, Cu and

activated Zn sulfides.

AAEERROOFFLLOOAATT 3311 pprroommootteerr

– This is based on AEROFLOAT 25 pro-

moter, but contains a secondary collector to improve silver flotation.

Widely used for flotation of Pb from Pb/Zn ores and Cu/Pb from

Cu/Pb/Zn ores. Improves Ag recovery from these ores.

AAEERROOFFLLOOAATT 224411 pprroommootteerr

– This is the ammonium salt of

AEROFLOAT 25 promoter. Water soluble in all concentrations.

Most selective of all liquid AEROFLOAT promoters. Widely used

for flotation of Pb from Pb/Zn ores, and as a secondary collector

for some copper ores.

Diaryl Dithiophosphate Diaryl Monothiophosphate

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