, ▁followed ▁by ▁sol vent ▁extra ction ▁to ▁concent rate ▁the ▁le ached ▁co pper ▁and ▁elect row in ning . ▁ ▁Elect row in ning ▁co pper ▁diff ers ▁from ▁elect r ore f ining ▁in ▁that ▁elect r ore f ining ▁uses ▁a ▁co pper ▁an ode ▁that ▁is ▁dissol ved ▁and ▁re de pos ited ▁on ▁the ▁c ath ode , ▁while ▁in ▁elect row in ning ▁the ▁co pper ▁is ▁already ▁in ▁solution ▁and ▁is ▁extracted ▁from ▁the ▁solution ▁by ▁passing ▁a ▁current ▁through ▁the ▁solution ▁using ▁an ▁in ert ▁lead - al loy ▁an ode , ▁and ▁a ▁c ath ode . ▁ ▁The ▁ch lor ide ▁in ▁the ▁le ach ▁solution ▁at ▁Port ▁Pir ie ▁proved ▁to ▁be ▁a ▁problem ▁for ▁the ▁st ain less ▁steel ▁c ath odes ▁of ▁the ▁Isa ▁Process . ▁A ▁small ▁amount ▁of ▁the ▁ch lor ide ▁ ions ▁in ▁the ▁le ach ▁solution ▁passed ▁through ▁the ▁sol vent ▁into ▁the ▁electro ly te , ▁leading ▁to ▁a ▁reported ▁ch lor ide ▁concentration ▁of ▁ 8 0 ▁mill igr ams ▁per ▁liter ▁( “ m g / L ” ) ▁in ▁the ▁electro ly te . ▁The ▁presence ▁of ▁the ▁ch lor ide ▁in ▁the ▁electro ly te ▁caused ▁p itting ▁cor ros ion ▁of ▁the ▁st ain less ▁steel ▁c ath ode ▁pl ates . ▁After ▁trying ▁other ▁types ▁of ▁st ain less ▁steel , ▁B H AS ▁switched ▁to ▁using ▁tit an ium ▁c ath ode ▁pl ates . ▁