2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 10: Battery, Recycling, Environmental, Mining
| Editors: | Kongoli F, Kumar V, Aifantis K, Pagnanelli F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2016 |
| Pages: | 220 pages |
| ISBN: | 978-1-987820-54-6 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Solidification/stabilization of arsenic bearing gypsum sludge using Portland cement: effect of precalcination
Xing Zhu1;1FACULTY OF METALLURGICAL AND ENERGY ENGINEERING, KUNMING UNIVERSITY OF SCIENCE AND TECHNOLOGY STATE KEY LABORATORY OF COMPLEX NONFERROUS METAL RESOURCES CLEAN UTILIZATION, Kunming, China;
Type of Paper: Regular
Id Paper: 264
Topic: 10
Abstract:
Arsenic bearing gypsum sludge derived from lime/ferrous sulfate precipitation process is one of the biggest hazardous wastes in nonferrous metallurgy (Cu, Ni, Pb, Zn, Sn, et al.) industry in China. Nearly one million tons of arsenic bearing gypsum (ABG) sludge with different heavy metals content and leaching toxicity should have been well disposed, but it is simply preserved in a reservoir. Precalcination is proposed to improve solidification/stabilization (S/S) of ABG sludge using Portland cement. The S/S performances of ABG sludge precalcinated at the temperatures range from (200-700 ĦaC) and untreated ABG sludge is investigated by means of compressive strength, leaching characteristics, microstructure, qualitative and Acid Neutralization Capacity tests. The arsenic leaching toxicity of precalcinated ABG sludge obviously decreases when the precalcinated temperature increases to 600 ĦaC and higher. More than 40% of cement is demanded to meet the requirement for safe disposal of fresh sludge using S/S process (compressive strength >10 MPa, toxicity <5mg/L) for the uncalcinated sludge while using only 10% of cement in S/S process reaches that requirement. The stability of solidified matrix from precalcinated ABG sludge is greatly enhanced. Precalcination results in high efficiency and dependability of S/S process of ABG sludge using cement.