The Economic Production of Precursor-Type Nanosize Precious Elements

Extensive field and laboratory investigation has clearly demonstrated a previously undescribed presence of nanosize clusters (particles) of various transition elements, including the precious elements, firmly bonded to amorphous colloidal silica (a.c.s.), and widely distributed throughout the earth’s crust and upper mantle. These a.c.s. bonded clusters are less than bulk metal in size and, therefore, without being properly pretreated do not analytically exhibit all of their characteristic elemental properties. A geochemical consequence is the existence of a vast, virtually untapped resource, of precious elements and other transition elements that are of great potential economic importance if only they are initially artificially enlarged to bulk metal size and thus converted to “conventional” metal.

Bench testing has clearly demonstrated that by using secondary nucleation this precious element-bearing a.c.s. (precursor-type) may be converted to bulk size precious metal giving conventional assays, depending on the element, from approximately 35 to more than 75 Troy ounces per ton of geologic source material. All of the precious elements are present in the same ores existing as precursor-type elements. Subsequent pilot testing, proceeded by small scale batch production testing, has established a recovery method that is highly economical, environmentally friendly, and simple and inexpensive to operate.

The final product for sale or refining consists essentially of 75%, or more, fine-grained precious metal powder (“blacks), 15 to 25% granular silica, and small amounts of Fe. A single pre-selected precious element (ex., Pt) may be recovered during each batch treatment or, if desired, a pre-selected group of precious elements. The precious metals to be recovered may be predetermined in order to achieve simplicity of subsequent refining. The ore source is ubiquitous. For our pilot and production testing we have mainly used fly ash from coal combustion power plants. It contains excellent precursor-type precious element values, is easily purchased at a low cost, requires no grinding, and has a clean Material Safety Data Sheet.