In late 1965 General Mills announced the availability of a new liquid ion exchange reagent LIX-64, for the recovery of copper from various solutions, such as dump leach liquors. Acceptance of this material by the copper industry has been gratifying. A number of pilot plants have been operated, and at this writing there are four commercial plants either in operation or under construction. The properties and operating characteristics of this reagent have been described previous papers.
Chemistry of LIX-64N
As with LIX-64, LIX-64N operates on a hydrogen ion cycle:
(2RH)ORG + (Cu++ + SO4 =)AQ (R2Cu)ORG + (2H+ + SO4 = )AQ
(R2 Cu)ORG + (2H+ + SO4 =)AQ (2RH)ORG + (Cu++ + SO4 =)AQ
Chemically, the two reagents perform similarly, except LIX-64N operates either in an extended pH range or will perform the same task in a reduced number of stages.
A pilot circuit was assembled in the laboratory, consisting of four extraction stages, three strip stages, and a small electrowinning cell. This circuit was operated with both LIX-64 and LIX-64N under conditions as closely identical as possible for comparison purposes. A number of typical acid liquors (obtained from actual southwestern copper operations) were used as feed solutions. These liquors