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Foam separation of complex anions: Silver thiosulfate
Author(s) -
Bhattacharyya Dibakar,
Grieves Robert B.
Publication year - 1972
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690180137
Subject(s) - pulmonary surfactant , stoichiometry , chemistry , thiosulfate , cationic polymerization , aqueous solution , particle size , molar ratio , particle (ecology) , analytical chemistry (journal) , chromatography , sulfur , polymer chemistry , organic chemistry , biochemistry , oceanography , geology , catalysis
An experimental study is conducted of the ion flotation of Ag(S 2 O 3 )– and Ag(S 2 O 3 ) 2 3 – from an aqueous solution at p H 4.5 with a cationic surfactant. For initial solutions 2.0 × 10 −3 to 8.0 × 10 −3 M in total silver, optimum silver flotation at foam cesssation is achieved at a molar thiosulfate to silver ratio (Th/Ag) of 0.75 and surfactant to silver ratio (EHDA/Ag) of 0.5, at Th/Ag = 1.0 and EHDA/Ag = 1.1, and at Th/Ag = 2.0 and EHDA/Ag = 2.2. The silver flotation is 99 + , 98 + , and 92 + % at the three sets of ratios, respectively. At Th/Ag > 2.0, highly efficient flotation cannot be achieved due to decreased particle size, and perhaps by competition with free S 2 O 3 2− for the surfactant. The stoichiometry of the ion flotation product is established from relative silver and surfactant flotation rates. The stoichiometry is independent of foaming time, but is a strong linear function of EHDA/Ag and Th/Ag, in contrast to the stoichiometry of flotation products of other simple and complex anions. Rate data can be fit reasonably by a first‐order reversible model. The rate constant is an inverse function of EHDA/Ag, indicating the desirability of pulsed surfactant addition. Results are discussed in terms of the average ligand number of silver, particle size, and surface potential measurements.