湿式ボールミルを用いた黄銅鉱からの銅浸出の促進

摘要

銅は電線や伸銅品など様々な用途で用いられ，人類に欠かせないベースメタルの1つである。しかし近年，原料である銅鉱石の品位は減少傾向にあり，有害元素等の忌避元素の濃度も増加傾向にあることから，現状の乾式製鍊プロセスへの受け入れが困難になりつつある。そこで，乾式製鍊では取扱いが難しい難処理銅鉱石に対する銅生産プロセスとして湿式製練が注目されている。湿式製練とは，硫酸等を用いて銅鉱石から直接銅イオンを浸出させる方法であり，比較的品位の低い銅鉱石でも経済的に成り立ち得るとされている。%Simultaneous ball milling and leaching by sulfuric acid was applied to enhance copper leaching from copper concentrate consisted of chalcopyrite and pyrite with small amount of bornite. When copper leaching was conducted in ball mill with enough air, copper recovery after 96 hours increased to 34.1%, whereas it remained 16.4% in beaker test. Kinetic analysis results showed that leaching rate of chalcopyrite was increased about 100 times in ball milling test than in beaker test. XRD patterns of residue after leaching suggested that crystallinity of chalcopyrite was decreased in ball milling. Furthermore, leaching rate was mostly not increased when the particle size of sample was decreased. From above results, it was supposed that copper leaching with ball milling was enhanced by not only an increase of specific surface area of particles in sample but also low crystallization of chalcopyrite and explosion of new-reaction surface of chalcopyrite.