Arsenic in mining and smelting operations

Arsenic metal(As), with a silver gray or gray white metallic luster crystal or block solid appearance, some forms are brittle crystals, and the crystal structure is divided into yellow arsenic (cubic crystal system), gray arsenic (rhombohedral crystal system), black arsenic (amorphous), etc. depending on the form. Among them, gray arsenic is the most stable and common form, with a density of about 5.727g/cm ³, a melting point of 817 ℃ (under 2.8MPa pressure), a boiling point of 613 ℃ (sublimation), and relatively stable chemical properties at room temperature. It is not easy to oxidize in air and burns to produce arsenic trioxide when heated to 400 ℃. It is easily soluble in strong oxidizing acids such as nitric acid and aqua regia, and difficult to dissolve in water, hydrochloric acid, and dilute sulfuric acid, exhibiting special chemical activity.