期刊
JOURNAL OF HAZARDOUS MATERIALS
卷 185, 期 1, 页码 148-154出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.jhazmat.2010.09.009
关键词
Selenite; Selenium removal; Sodium sulfide; Selenium sulfide; Zinc refining; Hydrometallurgy; Effluent treatment; Precipitation
资金
- NSERC (Natural Sciences and Engineering Research Council of Canada)
- FQRNT (Fonds quebecois de la recherche sur la nature et les technologies)
- CEZinc
In this study, the removal/precipitation of selenium with sodium sulfide from initially weakly acidic sulfate solutions containing 300 mg/L of selenium(IV) at 23 degrees C was studied. The results showed that,below a pH of approximately 7.0, the precipitation reaction was complete at a sulfide to selenium ratio above 1.8 and less than 11 with less than 0.005 mg/L of soluble selenium remaining in solution. When the pH rose between 7.0 and 9.5 the precipitation of selenium was incomplete. Above pH 9.5 the solution turned dark red but no precipitation was apparent. The precipitation reaction started as soon as the sodium sulfide was added in the selenium-bearing solution and was completed in less than 10 min. The orange selenium sulfide precipitates, characterized using X-ray diffraction, scanning electron microscopy and chemical analysis, were crystalline in the form of aggregated dense particles with their sulfur/selenium molar ratio varying from 1.7 to 2.3. The precipitate was deduced to be a Se-S solid solution consisting of ring molecules of the following SenS8-n formula, where n = 2.5-3. Long term leachability tests (>2 month equilibration) under ambient conditions at pH 7 showed the produced precipitate to be essentially insoluble (<0.005 mg/L). (C) 2010 Elsevier B.V. All rights reserved.
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