未来の天然鉱山・都市鉱山３

[1K0508-10-01] Arsenic-bearing porphyry copper deposits: An overview of mineral processing strategies, extractive metallurgy techniques, and waste management approaches for environmental conservation

○Carlito Baltazar Tabelin¹, Ilhwan Park², Sanghee Jeon², Theerayut Phengsaart³, Mayumi Ito², Naoki Hiroyoshi² (1. University of New South Wales, 2. Hokkaido University, 3. Chulalongkorn University)

The chairman: Mayumi ITO (Hokkaido University)

Keywords:arsenic, copper, mineral processing, extractive metallurgy, risk evaluation

Porphyry deposits are the most economically important sources of copper (Cu), molybdenum (Mo) and gold (Au). Although of lower grade compared with other Cu-bearing deposits, porphyry copper deposits are more widespread and could contain from hundreds of millions to billions of tonnes of minable ore. Many porphyry Cu deposits contain Cu-sulphide minerals rich in arsenic (As) like enargite (Cu₃AsS₄), tennantite (Cu₁₂As₄S₁₃) and luzonite (Cu₃AsS₄) that end up in the concentrate during the processing of ores via conventional flotation techniques. Because As is highly toxic and the disposal of its compounds is subject to very strict protocols and requirements, smelters impose expensive penalties for Cu concentrates containing As above a certain threshold (~2%). Processing of Cu concentrates with over 5% As is also often declined by smelters. Several strategies have been developed to prevent As-Cu sulphides recovery in the final concentrate as well as to remove As from As-rich Cu concentrates. In this review, recent advances in the mineral processing of porphyry Cu ores containing As are introduced. Pyrometallurgical and hydrometallurgical strategies to treat As-rich Cu concentrates are also reviewed. Finally, As removal techniques from processing wastewaters and acid mine drainage (AMD) are discussed.