![]() The neutral Sb(OH) 3 species has been shown to be unreactive to H 2O 2, in the absence of catalytic trace metals, with the formation of Sb(OH) 4 − required for oxidation to proceed. Oxidation of Sb(III) by peroxide has been previously reported ( Quentel et al. In water Sb(III) (Sb(OH) 3 at pH 7) is stable under reducing conditions while Sb(V) (Sb(OH) 6 − at pH 7) is stable under oxidizing conditions ( Baes & Mesmer 1976), although it has been reported that Sb(III) and Sb(V) have been found to exist in significant quantities in oxic and anoxic waters, respectively ( Filella et al. Antimony is present in the catalyst in the +3 oxidation state ( Kim et al. Antimony chemistryĪntimony exhibits multiple oxidations states: −3, 0, +3 and +5 ( Baes & Mesmer 1976). Korean release regulations mean a suitable method to remove antimony from the process effluent is required in order to gain regulatory approval. However, the presence of antimony in the catalyst, which is subsequently found in the process effluent, is cause for concern. Phosphate removal by co-precipitation with ferric iron has already been shown to be effective under current process conditions ( Foster et al. Final Sb and PO 4 3− concentrations of 0.2 and 8 mg L −1 are permitted for release in Korea ( MoE 2018). The remaining effluent, containing between 25 and 50 mg L −1 antimony and 50 mg L −1 phosphate, requires final treatment before release. A uranium-phosphate precipitation step at pH 6.25 is then performed to remove uranium from the process effluent ( Foster et al. Hydrogen peroxide is added to the dissolved catalyst solution along with sodium carbonate for the formation of soluble uranyl peroxocarbonate (UO 2(O 2)(CO 3) 2 4−) enabling the separation of soluble uranium species and precipitated silica. A portion of the Sb is also solubilized, along with uranium and other trace metals (e.g. Treatment of the uranium–antimony catalyst involves dissolution of the silica support in sodium hydroxide followed by selective precipitation of the silica and its purification with sulfuric acid. In recent years a process has been successfully demonstrated to remove the uranium component for geological disposal, thus meeting all national and international regulations for radioactive waste treatment ( Kim et al. The spent uranium-containing catalyst, classified as radioactive waste, has since been in temporary storage awaiting an appropriate treatment and disposal method. Since then, U-free catalysts such as Cr/Sb/O or MoVTe(Sb)NbO x have been used. One such catalyst, containing a uranium–antimonite active phase (U = 3–7 wt%, Sb = 15–25 wt%) on a silica support (approximately 70 vol%), had been used in Korea until 2004 ( Cavani et al. Phosphate poses significant challenges for the removal of Sb(V) due to competition between PO 4 3− and Sb(OH) 6 − species for surface binding sites, attributed to similarities in chemistries and a shared preference for an inner vs outer binding mechanism. However, Sb(V) removal from SO 4 2− was significantly hampered requiring significantly higher iron dosages for the same removal performance. Removal of Sb(III) from both Cl − and SO 4 2− media and Sb(V) removal from Cl − media to below release limits were found to be effective within 5 minutes at an iron dose of 8 mM (molar ratio, / = 20) and a target pH of 5.0. The effect of selected anions – Cl −, SO 4 2− and PO 4 3− – have also been considered, the latter present due to a prior uranium removal step. Antimony(III/V) removal via co-precipitation with iron has been considered with optimal pH, dose and kinetics being determined. ![]() ![]() However, significant concentrations of antimony ( ≥ 25–50 mg L −1) remain in effluent from the process, which require removal in compliance with Korean wastewater regulations. Targeted removal, immobilization and disposal of the uranium component has been confirmed, thus eliminating the radiological hazard. ![]() With more water it forms Sb 4O 5Cl 2which on heating to 460° under argon converts to Sb 8O 11Cl l2.A treatment and volume reduction process for a spent uranium–antimony catalyst has been developed. With a limited amount of water it forms antimony oxychloridereleasing hydrogen chloride: SbCl 3 is readily hydrolyzed and samples of SbCl 3 must be protected from moisture. The soft colorless solid with a pungent odor was known to the alchemists as butter of antimony. These all grades are available in 5 kg pack to 50 kg packing in HDPE Drums or Bags.Īntimony Trichloride is the chemical compound with the formula SbCl 3. ![]() We are manufacturing Antimony Tri chloride in various forms. ![]()
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