▁hand , ▁the ▁an odes ▁normally ▁res ide ▁in ▁the ▁cells ▁for ▁ 2 4 – 2 8 ▁days , ▁meaning ▁that ▁there ▁are ▁two ▁c ath odes ▁produced ▁from ▁each ▁an ode . ▁▁ ▁The ▁st arter ▁sheets ▁have ▁a ▁t endency ▁to ▁war p , ▁due ▁to ▁the ▁mechanical ▁str esses ▁they ▁encounter ▁and ▁often ▁need ▁to ▁be ▁removed ▁from ▁the ▁ref ining ▁cells ▁after ▁about ▁two ▁days ▁to ▁be ▁straight ened ▁in ▁press es ▁before ▁being ▁returned ▁to ▁the ▁cells . ▁The ▁t endency ▁to ▁war p ▁leads ▁to ▁frequent ▁short - circ uit ing . ▁ ▁Due ▁to ▁their ▁limitations , ▁it ▁is ▁difficult ▁for ▁co pper ▁produced ▁on ▁st arter ▁sheets ▁to ▁meet ▁modern ▁specific ations ▁for ▁the ▁highest - p urity ▁co pper . ▁ ▁The ▁development ▁of ▁the ▁Isa ▁Process ▁technology ▁ ▁The ▁development ▁of ▁the ▁Isa ▁Process ▁tank ▁house ▁technology ▁had ▁its ▁beginning ▁in ▁the ▁z inc ▁industry . ▁During ▁the ▁mid - 1 9 7 0 s , ▁M IM ▁Hold ings ▁Limited ▁( “ M IM ” ) ▁was ▁considering ▁building ▁a ▁z inc ▁ref in ery ▁in ▁Town sv ille ▁to ▁treat ▁the ▁z inc ▁concent rate ▁produced ▁by ▁its ▁Mount ▁Isa ▁operations . ▁As ▁a ▁result , ▁M IM ▁staff ▁visited ▁the ▁z inc ▁sm el ters ▁using ▁the ▁best - p ract ice ▁technology ▁and ▁found ▁that ▁modern ▁electro ly t ic ▁z inc ▁sm el ters ▁had ▁adopted ▁permanent ▁c ath ode ▁plate ▁and ▁mechan ised ▁stri pping ▁technology