Froth Flotation (Sulphide & Oxide)

Froth Flotation (Sulphide & Oxide)

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Lead-Zinc Floatation (2 replies and 3 comments)

S
saibalmet
7 years ago
saibalmet 7 years ago

We are processing Pbs -Zns  ore . our plant consist of Ball Mill and Spiral classifier with 30 TPH capacity. Our main problem is that in our floatation cell in lead , in initial rougher cell we are getting very few amount of lead as an overflow but in scavenger we get a massive amount of overflow. we are using KEX as lead collector and its dosing point is lead condition and lead scavenger , we running very high amount of collector at conditioner ( 200lph with conc of  0.5%) for 80m3/h slurry. and 100lph in scavenger. I am not getting understand what is the issue because of that we are not getting lead in scavenger.

A
anewell
7 years ago
anewell 7 years ago
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Dear Saibalmet

It would be useful to better understand the mineralogy of your feed, however it is likely that you have a significant amount of oxygen consuming minerals and species in your feed - such as pyrrhotite, marcasite or framboidal pyrite. Milling with steel media and liners significantly increases the oxygen demand [OD](and galvanic coupling reactions) while a fine grind exacerbates the problem (increase surface area). The bottom line is that dissolved oxygen is required to float galena and your observations indicate that the OD has been satisfied by the end of  the roughing stage. I have encountered this problem at least twice and the solution was to aerate the flotation feed (i.e. conditioning) prior to flotation to satisfy the OD. At the time, I was working for a gas company, so we naturally used oxygen and called the technology Actifloat. We also wrote some papers on the subject.

Hope that this helps - easy to check this hypothesis with some laboratory testwork on the flotation feed.

Best regards

Andrew

 

J
J. Neumann
7 years ago
J. Neumann 7 years ago
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You might try a small amount of NaCN in the grinding circuit, in the 60-80 gram per tonne range.  That should help scavenge the oxygen and depress any activated minerals that are keeping the galena from floating in the roughers.

If that doesn't work, make sure your galena hasn't oxidized.  Occasionally PbS that has been stockpiled in a wet atmosphere (ie, under water) can oxidize making it very difficult to float.

S
saibalmet
7 years ago

Thanks .. already tried with NaCN in grinding circuit and it gives us the better result of lead floatation but still some fine fraction of lead misplacement is also in Zinc circuit observed .
But when we tried MBS as substitute of NaCN we are not getting that desired result lead misplaced at Zinc Circuit and Sphalerite flotation also very much sluggish. can you give me some idea on that ?

O
opg2729@gmail.com
7 years ago

What are the alternative chemicals to sodium cyanide for depressing pyrite in zinc flotation process?

J
J. Neumann
7 years ago

You could try a little starch. Not too much though.

Also, higher pH ranges typically help float zinc selectively away from pyrite.

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