Effect of NaOH on the vitrification process of waste Ni–Cr sludge

Chou, I-Cheng; Wang, Ya-Fen; Chang, Cheng-Ping; Wang, Chih-Ta; Kuo, Yi‐Ming

doi:10.1016/j.jhazmat.2010.10.079

Cited by 28 publications

(17 citation statements)

References 20 publications

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“…In a vitrification process, BP and density governed the distribution of metals. Metals with high BP and high density go into ingot; meanwhile those with high BP but low density stay in slag (Kuo et al, 2011). There was no ingot generated in this study process which is different from that vitrified other raw materials, such as spent batteries or electroplating sludge (Kuo et al, 2009;Kuo, 2012).…”

Section: Metal Mass Distribution Of Output Materialsmentioning

confidence: 70%

“…Therefore, the movement of metals with high BP and high density toward ingot was not found in this experiment. This can be explained that the levels of ingot forming metals, which are usually Co, Cr, Cu, Fe, Mn, and Ni according to previous studies (Kuo et al, 2011), were too low (< 1,000 mg/kg) and thus, there are insufficient amounts to form the ingot. Table 5 shows the TCLP results of the slag.…”

Section: Metal Mass Distribution Of Output Materialsmentioning

confidence: 91%

“…Second, it can destruct organic toxics such as PCDD/Fs, PBDE or PAHs (Kuo et al, 2003;Lin et al, 2011;Lin et al, 2012). Third, it can gather useful metals in the products as recoverable forms (Chou et al, 2011). This study attempted to investigate the vitrification of fly ash with the addition of cullet.…”

Section: Introductionmentioning

confidence: 99%

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Metal Behavior during Vitrification of Municipal Solid Waste Incinerator Fly Ash

Kuo

Huang

Lin

2012

Aerosol Air Qual. Res.

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This study described the mass distribution of metals and the crystalline characteristics of slag during the vitrification of incinerator fly ash. The fly ash, mainly composed of Ca (180,000 mg/kg), Si (25,500 mg/kg), Pb (19900 mg/kg), and Zn (14,400 mg/kg), was vitrified with cullet at a basicity of 0.921 in an electric heating furnace. After vitrification, metals with low boiling points (Cd, Pb, and Zn) vaporized into flue gas as particulate phase. High levels of Pb (315,000 mg/kg) and Zn (226,000 mg/kg) made the particulate phase worth reclaiming. No ingot formed due to lack of ingot forming metals, and thus metals with high boiling points mainly stayed in the slag. After being identified by X-ray diffractometer (XRD) analysis, the major crystalline phases of the slag were found to be Ca 2 SiO 4 and CaSiO 3 , which coincided with the results of scanning electron microscopy (SEM). The results of the toxicity characteristics leaching procedure (TCLP) suggest that recycling the slag could be taken into consideration. The overall results indicate that vitrification is a promising technology that is able to transform incinerator fly ash into stable slag, reduce secondary environmental pollution, and transform valuable metals (Pb and Zn) in a recoverable form.

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Section: Metal Mass Distribution Of Output Materialsmentioning

confidence: 70%

Section: Metal Mass Distribution Of Output Materialsmentioning

confidence: 91%

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Metal Behavior during Vitrification of Municipal Solid Waste Incinerator Fly Ash

Kuo

Huang

Lin

2012

Aerosol Air Qual. Res.

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“…A 10% mass ratio of silicon (99+%) was homogeneously mixed with the specimens as an internal standard for crystalline semi-quantitative analysis (Kuo et al, 2008). The XRD intensity was measured in the 2θ range of 10° to 60° with Ni-filtered Cu Kα radiation at 4°/min (Chou et al, 2011). The crystalline phases of the specimens were identified by comparing the peaks and profiles of the XRD data with the powder diffraction file (PDF) from the International Centre for Diffraction Data.…”

Section: Methodsmentioning

confidence: 99%

Metal Distribution Characteristics in a Laboratory Waste Incinerator

Chang

Shen

Chou

et al. 2012

Aerosol Air Qual. Res.

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The metal distribution in the emissions of a laboratory waste incinerator (LWI) was investigated. The input materials and output materials (fly ash, bottom ash, and flue gas) were analyzed to examine the transportation and transmission behavior of heavy metals.Toxic (As, Cd, Cr, Hg, Ni, and Pb), anthropogenic (Ag, Ba, Cu, Mn, Se, and Zn) and crust (Na) elements were adopted to characterize the distribution properties of the LWI under investigation. The results indicated that Ba, Cr and Hg (80.0, 13.0 and 12.9 mg/L, respectively) were the major metals in the organic liquid waste input, and Na, and Zn (7497 and 349 mg/kg, respectively) were the major ones for medical solid waste. The Na content in the fly ash could be as high as 911574 mg/kg, and this was found to be the major Na emission source according to the emission factors. The mass of Na may be supplied using a NaOH solution injection to neutralize the acidic combustion gas, and it was found that high contents of Na in the flue gas were from the sprinkled NaOH solution. For the output materials, NaCl was found to be the major crystalline form of Na in the ash, based on the results of X-ray diffraction (XRD) patterns. The crust (Na) element was the major element in the bottom and fly ash. The toxic (As, Cr, Ni, and Pb) and anthropogenic (Se) elements were mainly distributed in the second cooling tower ash and baghouse ash in a range of 64.5%-91.9%. The average concentrations of Pb, Cd, and Hg concentrations in the flue gas were all under Taiwan's EPA regulation standards.Toxicity characteristic leaching procedure (TCLP) data showed that the leachability of As, Cr, Cu, Hg, and Se exceeded the EPA's regulations. It is thus suggested that the ash should be treated by further elutriation or vitrification processes to reduce the TCLP levels in the final products.

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“…[9] However, there are few studies on the solidified effect of heavy metals on slag produced by different sludge sources and obtained by different cooling methods.…”

Section: Introductionmentioning

confidence: 99%