Hey Crosty!see my old post below....but particle size is another...

Hey Crosty!

see my old post below....but particle size is another matter really.

Also, my disclaimer: Zn is not my metal - but perhaps the answers may lay in simple thermodynamics.

As I may have mentioned before - I think that the Perkoa (coarse ground) con will have more potential buyers than a finely ground con such as the one you mentioned.

I suspect, the finer the grind (p80 of 15-20 microns) the more one has to sinter (kind of chemical agglomeration prepration phase to smetling) to get the concentrate into a form that can be roasted effectively (regardless of process route (ISF or Roast/Electrowin). Its all about porosity of the ore charge and allowing sufficent gas pathways (and surface area) for a reaction to occur. This is certainly the case with iron ore.

BTW, p80 means 80% of the concentrate (by weight) is less than 16-18 microns. I suspect with a single stage milling step at Perkoa, the grind size will be at least p80 of 100 microns (may even be 150 microns). Perkoa is typical of the old rich Sulphide cons of the 60's and 70's - most have been mined out by now. This means it can be processed pretty much anywhere or blended with poorer grade feed stocks.

I'd have to get my books out if you want the rest of the story - might even have to charge for it!

Hope it helps.

Sack

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Hi D,

From what I can tell, Votorantim are taking the bulk of the con (1/3 so far) and as such will probably run it through a roast and then electrowin process. Much of the Zn in the world is produced this way. I also know the have worked on some bioleach research in this area - gets rid of SO2 emissions. The former uses quite a lot of energy to produce Zn metal.

However, ye old ISF process (Independent Smelting Furnace Technology - I think it may have been Rio's oriinal claim to fame as RTZ in Bristol!) was developed some time ago and uses a pyro method for Zn production. A lot of the old smelters use(d) this technology - I hav not done a search at this stage. The ore con requires sintering first, then reduction into metal can be performed. Quite simple and cheaper from an energy perspective. Still get the SO2 though. It uses only a Zn sulphide con.

My guess is that VM will probably blend roasted Zn cons (from ZnS as well as other cons uch as ZnSO4) from many mines to get their refinery feed grades up. The whole lot would be roasted and then electrowon.

What does this all mean?

I think it means that a 'traditional' Zn con (i.e. AIM) may have place at ANY Zn refinery (pyro or hydro). If you produce a silicate con or Iron rich Zn con, chances are you will have to follow the roast, electrowin flowsheet.

So, if this is the case, AIM may be able to flog this con to the highest bidder.