Cost effective recovery of Rh from a continuous process waste stream

A chemicals manufacturer used rhodium as a catalyst to make a bulk chemical in a continuous process, which generated approximately 1 tonne of waste per day containing 200 ppm rhodium. Incineration and recovery of the contaminating metal recovered > 90% of rhodium but the cost of the refining made the process uneconomical.

Screening of the PhosphonicS scavenger library identified Phos-05 as the optimal scavenger. Optimisation and lab scale trial identified and validated the experimental conditions that allowed recovery of 95% of rhodium from the waste with 3.5% rhodium loading on the Phos-05 scavenger.

The business case was built upon the calculation that > 90% of rhodium could be recovered from the waste. After scavenger and refining costs, this translated into a 75% value recovery versus a net cost of the process.