Accredited Solutions Inc (ASII)

[tomasviejo]

There is a description in the paper, a link to which I sent to JR11, of a complex of Au with a metastable sulfur ion. I have to confess that when I took basic college chemistry, I was more interested in creating some chemistry between myself and one of the co-eds than I was in my chemistry classes themselves,and that was longer ago than I care to admit. So chemistry is somewhat unfamiliar territory for me. However, the central idea seems to be that the gold will form a metastable complex ion (AuS(5)-) with this S(5)-2 ion that the author says will exist in a solution containing sulfuric acid when pH is <8.5, and this can be used to advantage to recover gold from the resulting solution.

As JR11 said, the predominant precious metal to be recovered from the tailings is silver, and the way the author of this paper proposes to get silver out of the process stream is to precipitate it as AgCl. I gather this is done by treating the solution first with sulfuric acid and sodium nitrite in a closed reaction vessel at really pretty low temperature and pressure to get silver sulfate in solution, then with a sodium chloride solution to precipitate the silver as AgCl, leaving a sulfuric acid/sodium hydroxide solution (pH <8.5) in which any elemental sulfur dissolves and the metastable gold-sulfur complex forms. The author of this paper claims the reaction kinetics for the conversion of the metastable sulfur ions to stable forms are very slow, allowing the gold (if any) to be recovered from solution by electrowinning or other standard refining techniques.

There is a discussion of a commercial application to recover copper and silver by this method (with a process flowsheet) here:

NSC Pressure Leaching

Now none of this matters if this is not the process LSTG plans to use. I hope they answer your phone call with a good description of the process they do plan to use, and at least some description of the plant they are building. It would be great to see a process flow sheet, at least. Surely they've got one by now, if they're already sending money to the JV to build the plant. It would be great to see that on the web site, along with any recent (within the past six months or so) photos of the work in progress at the tailings pile they can get up there.