Comparative Study of Rhodium Recovery from Plating Solutions via Cementation, Chemical Precipitation and Electrowinning

Abstract:

Rhodium plating is currently in appreciable demand not only for automotive as in catalyst converter but also for jewelry industry due to its silvery-white appearance, allergy-friendly, durable, scratch and tarnish-resistant. In accordance with circular economy, to assure efficient reuse and deviating from primary resource reliance, rhodium recovery is therefore of significance as the secondary resources. This research investigated comparative study of rhodium recovery from the plating solution via three techniques: cementation, chemical precipitation and electrowinning. The fresh plating solution prepared from rhodium concentrate and additive solutions was diluted to 0.1, 0.2 and 0.4 g/L of rhodium and used as the equivalent spent plating solutions. It was found that both cementation using zinc powder and chemical precipitation using sodium hydroxide and ammonium hydroxide did not yield notable recovery and gave low purity recovered products. Electrowinning has shown be more effective among the three techniques. For electrowinning, the diluted solutions were used as electrolyte, while the current density was controlled at 0.08-0.14 A/cm² for 2-24 h. Rhodium could be obtained at the cathode, giving the average rhodium content of 94.02 wt.% and the purity of greater than 98%. At the greater rhodium concentration of 0.4 g/L, deposition of rhodium metal was uniform appearing as clusters of particles on the cathode surface where nucleation and growth are competitive.

• Periodical: Defect and Diffusion Forum (Volume 453)
• Pages: 101-109
• DOI: https://doi.org/10.4028/p-8XODp2
• Online since: July 2026
• Authors: Tapany Patcharawit*, Chatisa Kansomket, Napat Mahiwan, Sumita Chailoi, Thanapon Chandakhiaw, Loeslakkhana Sriklang
• Keywords: Cementation, Chemical Precipitation, Electrowinning, Plating Solution, Rhodium

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