Method and apparatus for extracting precious metals from their ores and the product thereof

An apparatus for extracting a precious metal from an ore comprising:

• means for producing a leaching solution, said solution comprising dissolved hydrogen sulfide gas and bisulfide ions, and having a fugacity of hydrogen gas
• and for reducing the fugacity of hydrogen gas in said leaching solution;
• means for exposing said ore to said leaching solution;
• and
• means for recovering said precious metal from said leaching solution.

A process of making a product, said product comprising a precious metal that can form a complex comprising bisulfide, said complex having an aqueous solubility, said process comprising the steps of:

• introducing an ore of said precious metal into an anaerobic reactor environment, said reactor environment having an activity of dissolved hydrogen sulfide gas, an activity of dissolved bisulfide ions, and a fugacity of hydrogen gas;
• increasing said activity of dissolved hydrogen sulfide gas and said activity of dissolved bisulfide ions and reducing said fugacity of hydrogen gas, whereby the solubility of the precious metal-bisulfide complex is increased;
• removing the precious metal-bisulfide complex from said reactor environment;
• separating said precious metal from said metal-bisulfide complex;
• and
• forming said product from said precious metal;
• wherein said increasing step and said reducing step are accomplished by at least one step selected from the group consisting of
• contacting said reactor environment with a culture of an oxyanion-reducing bacterium, and
• contacting said reactor environment with a stream of gas comprising hydrogen sulfide gas and a fugacity of hydrogen gas of less that 0.001 atmospheres.