PREPARATION OF CHROMIC OXIDE &CHROMIUM METAL FROM INDUSTRIAL WASTE WATER .

Abstract

Abstract

This research study is concerned with seeking routs to recover the chromiom concentrations of the leather tanning waste water in order to prepare highly pure chromic oxide as well as chromium metal by aluminothermic process.

The present tests revealed the possibility of precipitating almost all the chrome present in the waste water by neutralization of the acidic pH of these waters. Equivalent amounts of Na - Salts are also precipitated in this way.

The salts were removed by washing with water which upgraded the Cr2O3 content from 25.9% to 54.8% after washing. Further upgrading was achieved by calcination at 1200oC where the Cr2O3 content reached 98 - 96%. The weight recovery achivied was about 98% of the original Cr content in the waste water.

Chromium metal was prepared by alurminothermic reduction of Cr2O3 at 1200oC. About 98% of the oxide was reduced to metal in this way, which brings the overall recovery to about 96%.

Economic and technical feasibility are encouraging to recover Cr from leather tanning waste water on an industrial scale. This would substitute imported materials as well as minimizing the pollution problems.