Platinum metals-solution chemistry and separation methods (ion-exchange and solvent extraction)

Al-Bazi, Sargon J.; Chow, A.

doi:10.1016/0039-9140(84)80204-0

Cited by 167 publications

(26 citation statements)

References 87 publications

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“…The ion pair formed can be extracted into a suitable organic solvent. Trioctylamine was found to be an effective extractant of some chloride complexes of Pt, Pd, Os and Ru.8"0- 13,18,19 The experiments carried out in this work have shown that the osmium iodide complex reacts with trioctylamine, then the ion pair ((C8H17)3NH+)20sI62-is formed according to the reaction:…”

Section: Extraction Of Osmium Iodide Complex With Trioctylaminementioning

confidence: 81%

Selective Spectrophotometry Determination of Osmium in Aqueous Iodide Solutions or after Extraction with Trioctylamine-Carbon Tetrachloride

et al. 1997

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Osmium and ruthenium can be selectively isolated from a mixture of the noble metals by distillation in the form of 0504 and Ru04. In hydrochloric (or sulfuric) acid media and in the presence of iodide, 0504 is selectively reduced to osmium(IV) and the 05162-complex is formed. Quantitative conversion of Os(VIII) into this complex takes place in 0.8 M U solutions and in 0.04 M HCl (or 0.1 M H2SO4) within 5 (or 10 min), respectively. The 05162-complex reacts with trioctylamine ((C8HI,)3N) and the ion associate ((C8HI,)3NH+)2OsI62-is formed. The ion associate can be isolated from aqueous solutions by extraction into carbon tetrachloride. Both the OsI62-complex and the ion pair with trioctylamine can be used for spectrophotometric determination of osmium directly in aqueous solutions or after extraction into the organic solvent. Ruthenium does not interfere with the determination of osmium in the form of the 0sI62-complex. KeywordsNoble metals analysis, osmium, iodide complex, spectrophotometryDistillation of ruthenium and osmium in the form of volatile tetroxides, Ru04 and 0504, is generally a preliminary step of analysis of multicomponent samples of the noble metals.1'2 Most often hydrochloric acid is used as the absorbing solution for both the tetroxides. Ru(VIII) is easily reduced to lower oxidation states and chloride complexes are formed.2.4 In 6 -10 M hydrochloric acid, the RuCl62-complex is the main reduction product. Reduction of Os(VIII) in chloride solutions proceeds slowly. Quantitative conversion of osmium into the stable OsCl62-complex requires heating the solution for a minimum of 20 min at 90 -100° C.4,5 Ruthenium interferes with the determination of osmium in chloride solutions. Separation of osmium from ruthenium is generally carried out before the determination.1,2 It has recently been established that osmium can be determined in the presence of ruthenium in chloride solutions by derivative spectrophotometry after numerical calculation of absorption spectra of the OsCl62-and RuC162-complexes.4 The method is time consuming and requires a suitable modern instrument.The reduction of 0SO4 by iodide in hydrochloric (or sulfuric) acid medium has been studied in this work. It has been found that osmium(VIII) is rapidly reduced to osmium(IV) by I-anions at room temperature and the 05162-complex is formed. The complex is stable in aqueous solution. It can be a basis of spectrophotometric determination of osmium. It can also be used for preconcentration of osmium by extraction after the reaction with high molecular weight amines. The optimum conditions for quantitative extraction of osmium from aqueous solutions with trioctylamine ((CRH17)3N) into carbon tetrachloride have been established. Ru(VIII) is not reduced in iodide solutions under the conditions of osmium reduction and does not interfere with the determination of osmium. The rapid quantitative conversion of osmium into the 05162-complex in iodide solutions and the selective extraction of osmium with high molecular weight amines may be competitive to...

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Section: Extraction Of Osmium Iodide Complex With Trioctylaminementioning

confidence: 81%

Selective Spectrophotometry Determination of Osmium in Aqueous Iodide Solutions or after Extraction with Trioctylamine-Carbon Tetrachloride

et al. 1997

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“…In Southern Africa, the three major PGE operators Anglo American Platinum, Impala Platinum and Lonmin each have their own individual PGE refining process (Table 3). These technologies can be characterized as follows [34,[49][50][51][52]]:…”

Section: Oxidation Statesmentioning

confidence: 99%

“…Table 2. Key aspects of properties and chemistry of PGEs for the separation processes during PGE refining [34,49].…”

Section: Pge Refiningmentioning

confidence: 99%

PGE Production in Southern Africa, Part II: Environmental Aspects

et al. 2017

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Platinum group elements (PGEs, 6E PGE = Pt + Pd + Rh + Ru + Ir + Au) are used in numerous applications that seek to reduce environmental impacts of mobility and energy generation. Consequently, the future demand for PGEs is predicted to increase. Previous studies indicate that environmental impacts of PGE production change over time emphasizing the need of up-to-date data and assessments. In this context, an analysis of environmental aspects of PGE production is needed to support the environmental assessment of technologies using PGEs, to reveal environmental hotspots within the production chain and to identify optimization potential. Therefore, this paper assesses greenhouse gas (GHG) emissions, cumulative fossil energy demand (CED fossil ), sulfur dioxide (SO 2 ) emissions and water use of primary PGE production in Southern Africa, where most of today's supply originates from. The analysis shows that in 2015, emissions amounted to 45 t CO 2 -eq. and 502 kg SO 2 per kg 6E PGE in the case GHG and SO 2 emissions, respectively. GHG emissions are dominated by emissions from electricity provision contributing more than 90% to the overall GHG emissions. The CED fossil amounted to 0.60 TJ per kg 6E PGE. A detailed analysis of the CED fossil reveals that electricity provision based on coal power consumes the most fossil energy carriers among all energy forms. Results show that the emissions are directly related to the electricity demand. Thus, the reduction in the electricity demand presents the major lever to reduce the consumption of fossil energy resources and the emission of GHGs and SO 2 . In 2015, the water withdrawal amounted to 0.272 million L per kg 6E PGE. Additionally, 0.402 million L of recycled water were used per kg 6E PGE. All assessed indicators except ore grades and production volumes reveal increasing trends in the period from 2010 to 2015. It can be concluded that difficult market conditions (see part I of this paper series) and increasing environmental impacts present a challenging situation for the Southern African PGE mining industry.

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“…Therefore, Pd and Ag extraction by Sc-CO 2 from a specific matrix involves the formation of complex anions in the solid matrix-supercritical fluid phase interface, anion exchange and the mass transfer of ion-association complexes into supercritical fluid phase. The following dissolution reactions and mass transfer relations for molecular species are considered [32,36]:…”

Section: Extraction Efficiencies Of Pd and Ag In Various Co-solvent Smentioning

confidence: 99%

Direct extraction of palladium and silver from waste printed circuit boards powder by supercritical fluids oxidation-extraction process

Liu

Zhang

2016

Journal of Hazardous Materials

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Platinum metals-solution chemistry and separation methods (ion-exchange and solvent extraction)

Cited by 167 publications

References 87 publications

Selective Spectrophotometry Determination of Osmium in Aqueous Iodide Solutions or after Extraction with Trioctylamine-Carbon Tetrachloride

Selective Spectrophotometry Determination of Osmium in Aqueous Iodide Solutions or after Extraction with Trioctylamine-Carbon Tetrachloride

PGE Production in Southern Africa, Part II: Environmental Aspects

Direct extraction of palladium and silver from waste printed circuit boards powder by supercritical fluids oxidation-extraction process

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