Nitric acid gold purity. Being a powerful oxidizing agent, nitric acid reacts violently with many non-metallic compounds, and the reactions may be explosive. Depending on the acid concentration, temperature and the reducing agent involved, the end products can be variable. Reaction takes place with all metals except the noble metals series and certain alloys. As a general rule, oxidizing reactions occur primarily with the concentrated acid, favoring the formation of nitrogen dioxide (NO). However, the powerful oxidizing properties of nitric acid are thermodynamic in nature, but sometimes its oxidation reactions are rather kinetically non-favored. The presence of small amounts of nitrous acid
Acidophiles in acid mine drainage economically and from a conservation perspective. Control of these acidophiles and their harnessing for industrial biotechnology shows their effect need not be entirely negative. The use of acidophilic organisms in mining is a new technique for extracting trace metals through bioleaching, and offers solutions for the phenomenon of acid mine drainage in mining spoils. Upon exposure to oxygen (O) and water (HO), metal sulfides undergo oxidation to produce metal-rich acidic effluent. If the pH is low enough to overcome the natural buffering capacity of the surrounding rocks (‘calcium carbonate equivalent’ or ‘acid neutralising capacity’), the surrounding area may become acidic,