New recovery process for rhodium using metal vapor

Kayanuma, Yoshihiro; Okabe, Toru H.; Mitsuda, Yoshitaka; Maeda, Masafumi

doi:10.1016/s0925-8388(03)00666-2

Cited by 52 publications

(25 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For Zn oxidation, E rest is still higher ()1.49 V compared to )1.53 V for E rest without US and )1.6 V for E eq ) possibly due to an increase in Zn(II) concentration because of the chemical oxidation of Zn by OH . For the electrochemical reduction of ions [Fe(CN) 6 ] 3) under 20 kHz US, Compton et al [28] also observed such potential displacement to more anodic potentials resulting from chemical re-oxidation of the electrogenerated ferrocyanide anion.…”

Section: Prediction Of Limiting Step Through Evans' Diagramsmentioning

confidence: 99%

“…The main domains of application are hydrometallurgy [1][2][3][4][5][6], surface [7][8][9] and industrial waste [10][11][12] treatments and electrolyte purification [13][14][15]. For most systems [16][17][18], mass transfer of the noble metal ion controls the reaction rate and cementation kinetics can be modelled by an overall first-order reaction rate corresponding to diffusion-convection control.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improvement of a cementation process by ultrasound: case of the cadmium?zinc couple at a RDE

et al. 2005

View full text Add to dashboard Cite

This paper describes the impact of low frequency (20 kHz) ultrasound (US) on Cd(II)/Zn cementation implemented on a RDE geometry. With and without US the reaction is mass-transfer controlled with two-step first-order kinetics mainly connected to deposit evolution. US improves the kinetics but to a lower extent than expected from electrochemical Cd(II) reduction. The favourable turbulence enhancement due to the deposit without US is not present when applying US because the deposit is continually removed from the surface. The influence of parameters such as temperature, initial concentration of reactants and US power is also analysed.

show abstract

Section: Prediction Of Limiting Step Through Evans' Diagramsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improvement of a cementation process by ultrasound: case of the cadmium?zinc couple at a RDE

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Among these, dissolution is a key step, 5) because the subsequent separation and purification processes, such as solvent-extraction, co-precipitation, and ion-exchange methods, are designed for PGMs in solution. However, PGMs in the metallic state cannot be oxidized by the hydrogen ions in acids, because the standard reduction potentials of PGMs are more positive than that of hydrogen.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of alkali metal platinates and their dissolution behavior in hydrochloric acid

Kasuya

Miki

Morikawa

et al. 2013

J. Ceram. Soc. Japan

View full text Add to dashboard Cite

To decrease the environmental load due to current Pt dissolution processes that use strong acids in combination with oxidizing agents, the synthesis and dissolution of alkali metal platinates in hydrochloric acid (HCl) were examined. The alkali metal platinates were prepared by calcinating mixtures of Pt black and the alkali metal carbonates (Li, Na, K) at 600800°C in air. Li 2 PtO 3 powder was obtained through the calcination of a Pt black and Li 2 CO 3 mixture at 600°C. The formation of NaPt 3 O 4 and Na 2 PtO 3 was confirmed upon the calcination of Pt black and Na 2 CO 3 at 600800°C; however, unreacted Pt also remained in the calcined samples. The calcination of Pt black and K 2 CO 3 did not yield any Pt-containing oxides, even at 800°C. These results indicated that Li 2 CO 3 was the most active reagent among the examined alkali metal carbonates for the formation of alkali metal platinates. The dissolution of the resulting Li 2 PtO 3 in conc. HCl was monitored by inductively coupled plasmaoptical emission spectrometry. The results showed that Li ions leached into HCl prior to the Pt, and the solubilities of the metals increased with decreasing calcination temperature. The dissolution behavior of Li 2 PtO 3 was discussed based on the crystallite size and anisotropy of the crystal. A Pt dissolution process by way of these platinates is expected to benefit the establishment of recovery processes for PGMs with low environmental loads.

show abstract

“…[19][20][21][22] When this treatment was carried out using the vapor of reactive metals (R) such as magnesium (Mg) to form Mg-Pt compounds, the dissolution efficiency of Pt improved in aqua regia (a mixture of HCl [35 pct, 30 mL] and nitric acid [HNO 3 , 70 pct, 10 mL]). In the dissolution experiments, only 14 pct of pure Pt dissolved in 4 hours, whereas the Pt component from the Mg-Pt compounds completely dissolved in 1 hour.…”

Section: Introductionmentioning

confidence: 99%

Effective Dissolution of Platinum by Using Chloride Salts in Recovery Process

Horike

Morita

Okabe

2012

Metall Mater Trans B

Self Cite

View full text Add to dashboard Cite

Platinum (Pt) is typically recovered by employing dissolution processes in aqueous solutions; however, these processes require a long processing time and considerable quantities of acids with strong oxidants owing to the high chemical stability of Pt. In order to develop an efficient dissolution process, we studied chlorination treatments for Pt prior to dissolution. Chlorination was carried out at 673 K to 873 K (400°C to 600°C) using copper(II) chloride (CuCl 2 ) as a chlorine source. While pure Pt was insoluble in hydrochloric acid (HCl(aq)), the entire Pt component of the treated sample dissolved in HCl(aq) under certain conditions. Therefore, the proposed method can be used as a new, environmental friendly Pt recovery process.

show abstract

New recovery process for rhodium using metal vapor

Cited by 52 publications

References 9 publications

Improvement of a cementation process by ultrasound: case of the cadmium?zinc couple at a RDE

Improvement of a cementation process by ultrasound: case of the cadmium?zinc couple at a RDE

Synthesis of alkali metal platinates and their dissolution behavior in hydrochloric acid

Effective Dissolution of Platinum by Using Chloride Salts in Recovery Process

Contact Info

Product

Resources

About