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| Study on Stabilization by Step for Arsenic in Waste Acid |
| Received:September 14, 2016 Revised:October 13, 2016 |
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| DOI： |
| KeyWord:arsenic, waste;acid, scorodite, stabilization |
| Author | Institution |
| Yin Yinan |
北京矿冶研究总院 |
| Wang Haibei |
北京矿冶研究总院 |
| Zhao Lei |
北京矿冶研究总院 |
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| Abstract: |
| Based on combined form and properties of arsenic in waste acid, using stabilization by step technique, which is different from traditional and harsh treatment conditions, for arsenic stabilization. Firstly, system acidity was reduced by calcium carbonate powder. Then, under normal temperature and pressure, dosing ferrous salt and oxidant into solution system for generating scorodite precursor. Finally, controling system low supersaturation by two technologies including atmospheric hydrothermal aging and pressure stabilization to make precursor for contimuously aggregation, crystallization, crystal nucleus stable growth, forming high crystallinity scorodite particles. Each factor effecting on arsenic stabilization were investigated, the results showed that reaction conditions of acid reduction are time is 30 minutes and terminal pH value for 1.8. Controling Fe and As molar ratio for 1.3:1, H2O2 and Fe molar ratio for 1:1, and time is 30 minutes to synthesis precursor. Controling terminal pH value for 4, the temperature of water bath for 95℃ and time for 7 hours to synthesis scorodite crystal, or in pressure reactor, scorodite crystal were synthesised under temperature on 180℃ and time for 3 hours. Obtained arsenide were confirmed to be scorodite by XRD, and the concentration of leaching toxicity for arsenic was lower than the limit from “Hazardous Waste Judging Standard for Leaching Toxicity Judging”(GB 5085.3-2007), arsenic stabilization was realized. |
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