A systematic study of cement/PFA chemical stabilisation/solidification process for the treatment of heavy metal waste

Poon, Chi Sun; Lio, K. W.; Tang, Chong I.

doi:10.1177/0734242x0101900403

Cited by 16 publications

(6 citation statements)

References 6 publications

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“…Accordingly, the leachability of the waste is reduced and the final product is easier to handle and transport. Among the various types of binders used for the s/s process, cement-based systems have been widely used to minimize leaching of contaminants from hazardous wastes (Cheng and Bishop, 1996;Poon et al, 2001;Zhang and Bishop, 2002;Leist et al, 2003). Pulverized fuel ash (PFA), a byproduct of coal-fired power generation, is often incorporated into the cement-based s/s process to reduce costs (Connor, 1990;Ubbriaco and Calabrese, 1998;Mollamahmutolu and Yilmaz, 2001).…”

Section: Introductionmentioning

confidence: 98%

Feasibility of Using Reject Fly Ash in Cement-Based Stabilization/Solidification Processes

Poon

Qiao

Cheeseman

et al. 2006

Environmental Engineering Science

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Stabilization/solidification (s/s) has been routinely used for the final treatment of hazardous wastes prior to land disposal. These processes involve adding one or more solidifying reagents into the waste to transform it into a monolithic solid with improved structural integrity. Cement-based systems with partial replacement by pulverized fuel ash (PFA) have been widely used to minimize leaching of contaminants from hazardous wastes. The finer fraction of PFA (Ͻ45 m, fine fly ash, fFA), produced by passing the raw ash through a classifying process is commonly used in s/s processes. Low-grade fly ash is rejected (rFA) from the ash classifying process, and is largely unused due to high carbon content and large particle size but represents a significant proportion of PFA. This paper presents experimental results of a study that has assessed the feasibility of using rFA in the cement-based s/s of a synthetic heavy metal waste. Results were compared to mixes containing fFA. The strength results show that cement-based waste forms with rFA replacement are suitable for disposal at landfill and that the addition of heavy metal sludge can increase the degree of hydration of fly ash and decrease the porosity of samples. Adding Ca(OH) 2 and flue gas desulphurization sludge reduces the retarding effect of heavy metals on strength development. The results of the Toxicity Characteristic Leaching Procedure and Dynamic Leach Test show that rFA can be used in cement-based s/s wastes without compromising performance of the product.

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Section: Introductionmentioning

confidence: 98%

Feasibility of Using Reject Fly Ash in Cement-Based Stabilization/Solidification Processes

Poon

Qiao

Cheeseman

et al. 2006

Environmental Engineering Science

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“…S/S is used to treat several types of wastes, prior to landfilling or reuse. They are especially applied to hazardous wastes, in order to decrease the release of toxic compounds, reducing the contamination of soil and water (Bayar and Talinli, 2013; Poon et al, 2001). According to the US Environmental Protection Agency (USEPA, 1979), this can be accomplished by different mechanisms, including: Chemical reactions that lead to the formation of inert compounds; reduction of solubility by changing pH and redox potential; wrapping the waste with coating.…”

Section: Introductionmentioning

confidence: 99%

Non-conventional stabilisation/solidification treatment of industrial wastes with residual powdered paints

Vaccari

Castro

2019

Waste Manag Res

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Stabilisation/solidification technologies are widely used for rendering industrial wastes inert. In this study, residual powdered paints were applied to treat different types of industrial wastes by stabilisation/solidification: Fumes from steel-making process, sludge from coagulation/flocculation treatments and powders from brushing and polishing metallic objects. Stabilisation/solidification trials were performed both under static conditions and in motion. It was observed that the residual paints could polymerise well in 60 min at 120 °C. The addition of water during the treatment resulted in highly porous and friable materials and, therefore, is not recommended. The mixture between wastes and paint influenced polymerisation. Specific heating conditions needed to be tested for each waste, varying from 80 °C to 150 °C. Significant reduction on leachability after treatment could be reached in most cases. Reduction on chlorides release up to 92.0% were achieved. Contents of other elements on the leachates, such as copper, molybdenum, nickel, zinc and dissolved organic carbon, could also be reduced in percentages up to 96.9%, 97.6%, 98.8%, 95.7% and 96.9%, respectively. For some types of wastes, however, especially those containing high contents of copper and mineral oils, the treatment was ineffective. Polymerisation in motion apparently improved binding capacity, but tests with increased content of paints are recommended to reduce the release of dissolved organic carbon.

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“…In the following period the values have stabilized and were around 7.5, due to mutual neutralization of the present materials, indicating that the leachates are not aggressive and corrosive in nature. Observing different mixtures it was concluded that pH values were not greatly affected by increased portion of the sludge [7,42]. In a similar manner conductivity was lower at the beginning of the test as the leachates were renewed every day.…”

Section: Figure 3 -Ph and Conductivity Measurements Of Collected Leacmentioning

confidence: 85%

Treatment of pyrite cinder sludge after usage in dye degradation: Feasibility study

Kerkez¹,

Bečelić‐Tomin²,

Dalmacija³

et al. 2016

Zas Mat

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Over the last couple of years greener concept in hazardous waste management is gaining increasing relevance. This term refers to the processes and activities that have little or negligible impact on the environment. The aim of this study is to systematically quantify the physical and chemical properties of the solidified/stabilized (S/S) sludge generated in dye effluent treatment, when pyrite cinder is used as catalytic iron source in the modified heterogeneous Fenton process. S/S treatment was performed by using two clay materials (kaolinite and bentonite) and lime in order to immobilize Cu, Pb and Zn present in the sludge. Microwave assisted sequential extraction procedure was employed to assess potential metal mobility and risk to the environment. In order to determine the long-term behaviour of the S/S mixtures, the semi-dynamic ANS 16.1 leaching test was performed. S/S effectiveness was evaluated by measuring the cumulative fractions of leached metals, effective diffusion coefficients -De and leachability indices -LX. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were implemented to elucidate the mechanisms responsible for immobilization of the

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A systematic study of cement/PFA chemical stabilisation/solidification process for the treatment of heavy metal waste

Cited by 16 publications

References 6 publications

Feasibility of Using Reject Fly Ash in Cement-Based Stabilization/Solidification Processes

Feasibility of Using Reject Fly Ash in Cement-Based Stabilization/Solidification Processes

Non-conventional stabilisation/solidification treatment of industrial wastes with residual powdered paints

Treatment of pyrite cinder sludge after usage in dye degradation: Feasibility study

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