Browsing by Author "Otero, AF"

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    Evaluation of saponins as acid mist suppressants in zinc electrowinning
    (ELSEVIER SCIENCE BV, 2004) Cheng, CY; Urbani, MD; Miovski, P; Kittelty, D; Otero, AF; San Martin, RM
    Generation of acid mist is a major concern in zinc electrowinning (EW) due to its detrimental effects on worker's health, the environment and plant infrastructure. One of the effective methods for acid mist control is to form a foam layer above the electrolyte surface by using surfactants. In this work, two saponin-rich products (Mistop(R) and QLZinc(R)) and a commercial Licorice product were evaluated and compared as acid mist suppressants in zinc EW Foam properties, acid mist suppression, phase separation in solvent extraction, cathodic current efficiency (CE) and cathode quality were correlated to the addition of these surfactants. Foam properties studied included minimum soluble solids dosage for 100% foam coverage, time required to achieve 100% foam coverage and foam persistence time.
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    Use of quillaja saponins (Quillaja saponaria Molina) to control acid mist in copper electrowinning processes - Part 1. Laboratory scale evaluation
    (ELSEVIER SCIENCE BV, 2005) San Martin, RM; Otero, AF; Figueroa, M; Escobar, V; Cruz, A
    This work describes the use of extracts of the Chilean quillaja tree (Quillaja saponaria Molina) as alternative low cost surfactants for the control of acid mist in copper electrowinning (EW). Quillaja extracts contain triterpenoid saponins, which are natural surfactants traditionally used as foaming agents in food and beverages. Two commercial products with different degrees of purification were tested: QL 1000 (R) (non-refined product, 8.4% saponin content) and Mistop (R) (refined product, 16% saponin content). Laboratory experiments determined the effects of both products on electrolyte surface tension (ST), solvent extraction process (SX), current efficiency (CE) and cathode quality.
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    Use of quillaja saponins (Quillaja saponaria Molina) to control acid mist in copper electrowinning processes - Part 2: Pilot plant and industrial scale evaluation
    (ELSEVIER SCIENCE BV, 2005) San Martin, RM; Otero, AF; Cruz, A
    This work describes the use of Mistop (R), a novel surfactant of natural origin that contains primarily triterpenoid saponins (active ingredient), to control acid mist in copper electrowinning (EW). Previous laboratory tests indicated that Mistop (R) has no negative effects on cathode quality, current efficiency, and overall solvent extraction (SX) process conditions (e.g. phase disengagement time, extraction/stripping kinetics, maximum charge/discharge, etc.).