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Gold/Mining/Energy : International Precious Metals (IPMCF) -- Ignore unavailable to you. Want to Upgrade?

To: Zeev Hed who wrote (23232)	10/25/1997 10:06:00 PM
From: E. Charters	Read Replies (1) \| Respond to of 35569

What you have described is the superheated fire assays that those guys in Salt Lake City have been working on since the early 70's. It is a variant on fire assay. All the principles you have described about fluxes are basic principles of the fusion procedure. All refractory metals are known to oxidize with KNO3 by the method standardized by Lakeshore Mines in the 30's. If I did a very high temperature sesquisilicate or trisilciate assay that is what I would get .. I could experiment with several different collectors as many have and I have my proprietary bunch. You can even use tellurium as a collector. The element selenium can make the gold dissolve in the cupel so that could screw things up but you can solve that by finishing AA on the lead button. There may be a fluxing problem with fire and there may be a preg robbing or precipitatory problem with chemical or AA. But a ten step chemical dissolution and precipitation with Hydrogen Cyanate should isolate the gold and give you a chemical determination that is accurate. If there are hydrocarbons that would be the only thing I can conceive that would foil the chemical method. The thing is..what is it that prevents a normal assay? If the gold is merely fine then a gas attack by chlorine and sulfur should get at it .. the Russians have a technique... Finally colloidal gold in hydrocarbons .. algal mats up to a tenth of an ounce with no known method of recovery can be fire assayed accurately and have been for 85 years in Asia. So I realize there are difficult ores to assay .. but where there is a will there is generally a way..and the thing that rankles me is every time these guys step up to the plate they strike out ... Ledoux found gold in their reagants once..I dunno..it is intriguing but there is that funny smell... EC<:-} echarter@vianet.on.ca

To: Zeev Hed who wrote (23232)	10/25/1997 10:38:00 PM
From: E. Charters	Read Replies (1) \| Respond to of 35569

BTW the collector in a gold assay is native silver. It stays metallic throughout the assay. The other collector host is lead, which is added as an oxide to oxidize the silicate material and comes down as metal in the button. It is a lead amalgam. To collect a finely divided metal you must have a turgid viscous melt until it reaches 1857 degrees. The it must become very fluid to pour well. I have a way to disseminate the collector and pre-oxidize fine metals that contain gold without causing volatilization that would result in losses. There is no point in going to temperature past the slagging of the refractory metals. That would be much less than the 2100 melting point of gold. You must remember that the average gold size in Canadian mines may in some case be as low as 20 microns..and we have our share of refractory gold tied up in arsenopyrite and pyrite atomically. You will notice our gold industry is quite healthy despite the price. As a matter of fact it was Canadian companies in Arizona and Nevada that revived the American gold mining industry and made it one of the world leaders, now surpassing Canada which used to out-produce America by 2 to 1. I think you will find that at a yellow heat virtually all the metal is at the bottom of the melt. When you put the gold and lead slip by quick as a wink and are first into the crucible. That tells me to heat slowly with refractories and keep it at a low temp for a long time while they oxidize and along with the silicates. It also tells me to have a finely divided collector well distributed throughout the assay. This is the chief weakness of the standard assay and may well cause low reporting in a fine metal system. I have a way of making sure the collector reaches the metals but I won't share it. I guess its ok if it dies with me. Having said that and being aware of the Salt Lake City work for the last 20 years I am saddened by the sorry approach to the matter by some obviously recalcitrant companies. They don't do research or the industry any good. echarter@vianet.on.ca