A hydrometallurgical process for the recovery of metal values from spent Cu-Cr catalyst.

Copper-chromium catalyst has been used in many chemical processes and dumped in landfill after losing its catalytic property. Owing to the toxicity of Cr the dumping of catalyst is not environmentally acceptable, so metal values should be removed before disposal. One typical Cu-Cr catalyst was leached with sulphuric acid and from the leach liquor Cu and Cr were extracted using LIX 860N and NaD2EHPA, respectively. The McCabe-Thiele diagram at pH 3.5 with 20% LIX 860N indicated two stages at A:O=1:1 for quantitative extraction of Cu. The stripping of Cu was achieved by 10% sulphuric acid. After the extraction of Cu, the extraction of Cr was carried out with NaD2EHPA. The McCabe-Thiele diagram for Cr extraction with 0.5 M NaD2EHPA at pH 3.0 showed two stages at A:O ratio of 1:1. The loaded organic of Cr was stripped with a mixture of sodium carbonate, sodium hydroxide and hydrogen peroxide. (Authors).
Copper-chromium catalyst has been used in many chemical processes and dumped in landfill after losing its catalytic property. Owing to the toxicity of Cr the dumping of catalyst is not environmentally acceptable, so metal values should be removed before disposal. One typical Cu-Cr catalyst was leached with sulphuric acid and from the leach liquor Cu and Cr were extracted using LIX 860N and NaD2EHPA, respectively. The McCabe-Thiele diagram at pH 3.5 with 20% LIX 860N indicated two stages at A:O=1:1 for quantitative extraction of Cu. The stripping of Cu was achieved by 10% sulphuric acid. After the extraction of Cu, the extraction of Cr was carried out with NaD2EHPA. The McCabe-Thiele diagram for Cr extraction with 0.5 M NaD2EHPA at pH 3.0 showed two stages at A:O ratio of 1:1. The loaded organic of Cr was stripped with a mixture of sodium carbonate, sodium hydroxide and hydrogen peroxide. (Authors).