สิ่งแวดล้อม มลภาวะ ของเสีย
เอกสารมาตรฐาน
สหรัฐอเมริกา
APHA
SMWW 3500-Au
Gold
2023
1
Standard methods for the examination of water and wastewater (543.3 APHA 24th ed. Ref. Treatises&monographs FL2)
Gold (Au) is the third element in Group IB in the periodic table. It has an atomic number of 79, an atomic weight of 196.97, and valences of 1 and 3. The average abundance of Au in the earth’s crust is 0.004 ppm; in streams it is 2 μg/L; and in groundwater it is <0.1 mg/L. Gold occurs in its native form, and is associated with quartz or pyrite. The main uses of gold are in jewelry, dentistry, electronics, and the aerospace industry...