…made visible by the preferential leaching (removal of material by solution) of the host substance with a suitable chemical reagent; the leaching process allows the etched fission-track pits to be viewed and counted under an ordinary optical microscope. The amount of uranium present can be determined by irradiation to produce…

Oxides are leached with a sulfuric acid or sodium carbonate solvent, while sulfates can be leached with water or sulfuric acid. Ammonium hydroxide is used for native ores, carbonates, and sulfides, and sodium hydroxide is used for oxides. Cyanide solutions are a solvent for…

…containing sodium chromate, which is leached from the insoluble gangue and then reduced and precipitated as Cr₂O₃. The Cr₂O₃ is blended with finely divided aluminum powder, charged to a refractory-lined container, and ignited. The combustion quickly generates temperatures in excess of 2,000 °C (3,600 °F), giving a clean separation of…

Occasionally adopted in preference to smelting (or pyrometallurgy, as it is generally known), leaching, or hydrometallurgy, is carried out at lower temperatures and thus eliminates the generation of sulfur dioxide; there are, however, effluents and residues that must be treated in order to protect…

The alkali ions thus leached out of the glass further react with carbon dioxide and water in the atmosphere to produce alkali carbonates and bicarbonates. These are seen as the white deposits that form on a glassy surface in dishwashing tests or after extended humidity exposure (often called weathering).…

…process is the ammonia pressure leach, in which nickel is recovered from solution using hydrogen reduction, and the sulfur is recovered as ammonium sulfate for use as fertilizer. In another, the matte may be roasted to produce high-grade nickel oxides; these are subjected to a pressure leach, and the solution…

…that may interfere in subsequent leaching operations.

…a coproduct with uranium by leaching the ore concentrate for 24 hours with hot sulfuric acid and an oxidant such as sodium chlorate. After removal of solids, the leachate is fed into a solvent extraction circuit where the uranium is extracted in an organic solvent consisting of 2.5-percent-amine–2.5-percent-isodecanol–95-percent-kerosene. Vanadium remains…