Abstract

A practical method of recovering chrome from tannery waste liquors for re-use has been developed. Spent chrome bearing liquor is collected, treated with magnesium oxide and allowed to settle. After discarding the supernatant solution the chrome precipitate is solubilised with sulphuric acid. The recovered chrome can be recycled to tannage; a prolonged trial showed that no deleterious effect accumulated in the leather produced. The system minimises both capital and labour costs; model calculations indicate a payback period (at 1981 prices) of 14-22 months, with considerable savings thereafter.