Froth Flotation (Sulphide & Oxide)

Froth Flotation (Sulphide & Oxide)

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Native Copper Flotation (8 replies)

S
Standartenfurer
8 years ago
Standartenfurer 8 years ago

Currently we have an operation in Peru which is having some troubles with native copper flotation, I would like to know is anybody has some experience floating copper native together with Cpy, Py, Bn.

Paul Morrow
8 years ago
Paul Morrow 8 years ago

We had native copper at Phelps Dodge Chino. Unfortunately, it doesn't float. When we ran into it in the pit, we had very high tails. When you panned the tails, all you could see were small copper "pennies". We tried a couple of different reagents but were never successful in floating it. Likely to do with it’s very high SG.

According to Cytec, their 5000 series promoters will collect Native Copper. Might be worth talking to them as reagents are evolving and improving all the time!

(unknown)
8 years ago
(unknown) 8 years ago

If you take a look back a long ways you can see hints in tech literature from native copper operations in Michigan. In some pilot plant work on these ores (much more recent time) we used xanthates and had decent recoveries. I'll have to see if any remaining details around operating conditions have. Benedict (1955) discusses development of flotation practice for native copper ores.

Conglomerate ores - Comment is made that Minerals Separation Co. was unable to get response. Test work at C&H involved testing various distillation by-products identified an active collector (active ingredient was pyridine). This was used with pine oil and creosotes as frothers. Even then problems in recovering plus 100 micron particles! Later practice moved to use of xanthates and pine oil. Additional detail inn Benedict (1930).

Amygdaloid ores – Comment is made that used xanthates and had acceptable recovery up to 35 mesh. Champion and other mines with this ore type used flotation. The hypothesis re acceptable coarse particle recovery for the amygdaloid ores vs. conglomerate ores was combination of grain size and liberation considerations.

Benedict, C.H., Milling Method And Cost At The Conglomerate Mill Of The Calumet & Hecla Consolidated Copper Co., IC 6364, 1930.

This paper presents the details of milling practice and costs at the conglomerate mill of the Calumet & Hecla Consolidated Copper Co., Lake Linden, Mich., and is one of a series on milling methods being published by the Bureau of Mines. GENERAL DESCRIPTION the mines of the Calumet & Hecla. Consolidated Copper Co. is located in the Keweenaw Peninsula of northern Michigan. The mines of this district lie in a belt not over 4 miles wide and 100 miles long, which contains more or less commercial ore. The Calumet & Hecla properties are the farthest north, except for the Seneca, of the operating mines. The district borders on Lake Superior, and by means of the Portage and Torch Lake waterways the largest lane vessels, can transport coal and other supplies from the lower Lakes directly to the company docks.

Benedict, C.H., Lake Superior Milling Practice, Mich. College of Mining and Technology Press, 1955.

U
Unterstarm
8 years ago
Unterstarm 8 years ago

The metallic copper may have a coating that is interfering with the collector. This might be removed by attrition. Depending on the amount and size of this native copper it could be building a circulating load in the milling circuit. This could be recovered by gravity methods from a bleed stream of the cyclone underflow. This has been used to recover native gold in copper flotation operations.

(unknown)
8 years ago
(unknown) 8 years ago

Can you comment on size distribution of the native copper and its liberation characteristics?

Paul Morrow
8 years ago
Paul Morrow 8 years ago

One problem with native copper is it tends to smoosh together to form larger particles because it is soft and pliable (sorry not a very technical term). When we ran into it at Chino, we would end up with pancakes of the stuff in pumps, pumpboxes, cyclone tubs, etc. We did consider a gravity circuit as mentioned but did not have the capital for it. It was also much hit and miss in the pit.

O
OberstGruppen
8 years ago
OberstGruppen 8 years ago

All the operation I know of with significant amounts of native copper turned to gravity. I believe Ernest Henry used spirals, the new CuDeco Rocklands project is looking at All Mineral jigs and I've also seen Test work with Gekko's IPJ that separated it we'll in the grinding circuit.

(unknown)
8 years ago
(unknown) 8 years ago

The US mill operation (no longer active) that had the largest amount of native copper that I called upon was Copper Range in White Pine, Michigan. Their ore was predominately chalcocite, with free native copper. They consume large amounts of potassium amyl xanthate as primary collector (they were 2nd largest consumer of xanthate at its time, behind Nchanga concentrator in Zambia), and stage added dodecyl mercaptan as collector for the native copper. The native copper would tend to float in the scavenger circuit, but would tend to concentrate itself in the regrind circuit, and often fell out in the re-cleaner circuit (if it made it that far!). They installed a "bleed" line in the regrind circuit, to take a portion and send it to a separate small float circuit, where they attempted to recover as much of the native copper, which was then routed to final concentrate. To support the high SG of the native copper and to overcome the large dosage of collector, they used a very strong mixed polyglycol frother to provide a strong froth base. You may find that potassium amyl xanthate to be too non-selective in your application, but I would consider testing some dodecyl mercaptan, which is generally cut by chemical suppliers in some type of oil, as a supplemental collector. Generally, other oil-based collectors, (thionocarbamates, i.e. IPETC) are too selective. Also, if the circuit will tolerate it, consider stage addition of a polyglycol based frother to help support the native, which will collapse most weak alcohol based froths.

Victor Bergman
8 years ago
Victor Bergman 8 years ago

A bleed to a gravity circuit can have a relatively quick ROI. You might want to check out the use of Nelson concentrators, which can also significantly raise gold recovery prior to the flotation circuit. For reference you may want to look at the work done at the now closed Kemess South operation. PAX (potassium amyl xanthate) was also the collector used during the ore run with native copper.

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