scholarly journals The Recovery of Ca and Zn from the Municipal Solid Waste Incinerator Fly Ash

2020 ◽  
Vol 12 (21) ◽  
pp. 9086 ◽  
Author(s):  
Chen-Piao Yen ◽  
Song-Yan Zhou ◽  
Yun-Hwei Shen
Keyword(s):  
Fly Ash ◽  
Ion Exchange ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Reduction Rate ◽  
Acid Leaching ◽  
Treatment Method ◽  
Waste Incinerator ◽  
Mswi Fly Ash ◽  
Water Washing

The treatment and disposal of municipal solid waste incineration (MSWI) fly ash containing significant amounts of dissolvable salts and heavy metals is a seriously challenge. At present, the common treatment method for MSWI fly ash in Taiwan is the cement-based stabilization/solidification (S/S) process. In this work, an integrated hydrometallurgical process for the treatment of MSWI fly ash was evaluated. Ca was first recovered by combining water washing and ion exchange sequentially. Meanwhile, Zn in the water-washed fly ash was recovered by combining acid leaching and ion exchange sequentially. Combining the water washing efficiency of 30% on raw ash and the acid leaching efficiency of 40% on pre-washed ash, a total of 58% mass reduction rate of fly ash was achieved. In addition, an 80% Zn and 58% Ca recovery was achieved.

Use of cement-chelated, solidified, municipal solid waste incinerator (MSWI) fly ash for pavement material: mechanical and environmental evaluations

2017 ◽  
Vol 54 (11) ◽  
pp. 1553-1566 ◽  
Author(s):  
Qiang Tang ◽  
Yu Zhang ◽  
Yufeng Gao ◽  
Fan Gu
Keyword(s):  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Chelating Agent ◽  
Waste Incinerator ◽  
Curing Time ◽  
Mswi Fly Ash ◽  
Element Analysis ◽  
Base Course ◽  
Pavement Material

As a by-product from the incineration of municipal solid waste (MSW), fly ash usually contains mobile heavy metals that may engender severe pollution when reused. In this study, fly ash was solidified with cement and a chelating agent to immobilize these polluting elements. The possibility of using the solidified fly ash for pavement materials was also assessed through mechanical and environmental perspectives. According to the results, the strength of solidified fly ash was found proportional to both the cement/fly ash ratio and curing time. This indicated that the increase of fly ash loading reduced the concentration of products from cement hydration, and thus destroyed the structure of the products of hydration. With the increase of freeze–thaw cycles, the compressive strength of cement-stabilized fly ash decreased between days 7 and 14, and then increased between days 14 and 28. Subsequently, the finite element analysis showed that placing the solidified fly ash layer as a pavement material between an unbound base course and subgrade was beneficial to prolong fatigue life and reduce rutting distress of asphalt pavements. Finally, leachability of metals from the mixtures was tested, which showed that leaching concentration decreased as the cement/ash ratio, curing time, and chelating agent content increased.

Sign in / Sign up

Export Citation Format

Share Document