Nitric Acid 64.6% (41° Baumé) (HNO3) is a highly corrosive mineral acid widely used in various industrial application. It is a clear to pale yellow in color and is a strong oxidizing agent known for its corrosive properties. It is commonly used in chemical manufacturing, metal processing, and as a laboratory reagent. This 64.6% Acid is in the high concentration range its slightly less azeotropic than 67% Nitric Acid which means it fumes less because the water and acid are not at the maximum boiling point. They are extremely close but the slightly small amount of extra water. You can achieve the reaction you are looking for it will fume less and take a little bit more time. Another note is that our sulfuric acid 93% can be used with nitric acid/water mixtures to help shift the azeotropic point to make highly concentrated fuming nitric acid.
Nitric Acid plays a key role in refining gold, particularly in methods like aqua regia refining and in parting processes. Urban mining and pcb board gold recovery commonly uses nitric acid to dissolve gold. *Ships in Level 4 Fluorinated Polyethylene Bottles, 55g ships in HDPE blue drum.
Aqua Regia Gold Refining Process (Most Common Use)
Aqua regia is a mixture of nitric acid (HNO₃) and hydrochloric acid (HCl) in a 1:3 ratio. This combination dissolves gold, which neither acid can do alone.
Step-by-step Overview:
Preparation of Aqua Regia:
Mix 1 part nitric acid with 3 parts hydrochloric acid.
Dissolution:
Add impure gold to the aqua regia.
Nitric acid oxidizes the gold to gold ions (Au³⁺).
Hydrochloric acid provides chloride ions (Cl⁻) to form chloroauric acid (HAuCl₄), which is soluble.
Filtration:
Filter the solution to remove impurities and undissolved metals.
Precipitation:
Add a reducing agent like sodium metabisulfite (Na₂S₂O₅) to the solution.
This causes pure gold to precipitate out of solution as fine particles.
Washing & Melting:
Wash the gold powder, dry it, and melt it to form pure gold bars or granules.
