Stabilization of Mine Waste Using Paper Sludge Ash under Laboratory Condition

Wajima, Takaaki; Shimizu, Tomoe; Ikegami, Yasuyuki

doi:10.2320/matertrans.mk200705

Cited by 5 publications

(3 citation statements)

References 22 publications

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“…Combustion is primarily used to reduce the volume of waste sludge for landfilling (80-90% reduction) and partly to recover energy, which produces paper sludge ash. Although paper sludge ash is used as a cement additive, soil amendment, water purification and so on [4][5][6][7][8][9][10][11], a large amount of ash is currently disposed of by dumping. This has caused environmental concerns and high costs to industry due to the shortage of landfill sites for waste disposal.…”

Section: Introductionmentioning

confidence: 99%

Effects of Step-Wise Acid Leaching with HCl on Synthesis of Zeolitic Materials from Paper Sludge Ash

Wajima¹

2020

Minerals

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Incinerated ash with a relatively high Ca content, paper sludge ash, was converted to zeolitic materials with high cation-exchange capacities (CECs) by aging at 80 °C in NaOH solution via step-wise acid leaching with HCl to reduce the ash Ca content. The extraction of Ca, Mg, Si, and Al from the ash into the acid solutions during leaching and the products obtained from the leached ash by reaction with an alkali were examined. The contents of Ca and Mg in the ash were more easily extracted from the ash than those of Si and Al in the initial leaching. The leachant pH decreased with increasing numbers of leaching steps, and the amounts of Si, Al, and Ca extracted from the ash increased as a result of the dissolution of gehlenite (Ca2Al2SiO7), one of the main minerals in the ash. Zeolites A and P were synthesized from the leached ashes, and hydroxysodalite was synthesized from the raw ash. With increasing numbers of leaching steps of the ash, the obtained product contained lower released Ca, whereas the product contained higher released Na and has higher CEC, depending on the zeolite phases in the product. The product with the highest CEC was synthesized from third-leached ash, and its CEC was 1.5 mmol/g, which is about four times higher than that of the raw ash (0.4 mmol/g).

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Section: Introductionmentioning

confidence: 99%

Effects of Step-Wise Acid Leaching with HCl on Synthesis of Zeolitic Materials from Paper Sludge Ash

Wajima¹

2020

Minerals

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“…Paper sludge ash (PSA) was produced by fluidized bed combustion of paper sludge for the volume reduction of waste sludge for landfill (80-90% reduction) and the partial recovery of energy. Although a part of PSA is used for some applications such as soil improvement, cement additive, water treatment and so on [4][5][6][7][8] , most part of ash is landfilled to cause environmental problems and high costs on paper industry for the shortage of landfill sites. Therefore, alternative routes to landfilling and the cost-reduction of PSA are desired.…”

Section: Introductionmentioning

confidence: 99%

Chemical Conversion of Paper Sludge Ash into Cation Exchanger Via Acid Leaching

Wajima

2022

J.I.E.

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Alkali conversion of paper sludge ash into cation exchanger via acid leaching was examined. The extraction behaviors of major elements (Si, Al, Ca and Mg) from the ash into hydrochloric acid (1 mol/L HCl) and sulfuric acid (0.5 mol/L H 2 SO 4 ) aqueous solutions were almost same except Ca due to the formation of gypsum in the H 2 SO 4 solution. The ashes leached with 1 mol/L HCl and 0.5 mol/L H 2 SO 4 aqueous solutions were converted into zeolite-P and tobermorite, respectively, while the raw ash was converted into hydroxysodalite. The cation exchange capacities of the converted products from the ashes leached with HCl and H 2 SO 4 were 1.30 and 0.75 mmol/g, respectively, which were higher than that of the product from the raw ash (0.60 mmol/g). These results indicated that paper sludge ash could be converted into different types of cation exchanger via acid leaching.

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“…EDTA is a common chelating agent, used as a Ca-masking agent to decrease the hardness of water. In a previous study, we applied Ca-masking with EDTA to synthesize highly functional zeolitic material from waste sandstone cake via alkali fusion and succeeded in obtaining a product with high cation exchange capacity, due to the inhibition of zeolite synthesis by the excess Ca content in BFS [6]. In this study, we applied Ca-masking with EDTA in the synthesis of zeolite crystals from BFS via alkali fusion.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Zeolite from Blast Furnace Slag Using Alkali Fusion with Addition of EDTA

Wajima

2014

AMR

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A large amount of blast furnace slag, a by-product of the iron-making process, is generated annually. We attempted to convert blast furnace slag (BFS) into zeolitic materials using alkali fusion with ethylenediamine tetraacetate dihydrate (EDTA) chelation. Without addition of EDTA, a mixture of hydroxysodalite and calcite was synthesized. With EDTA addition, Ca2+ ions were trapped by chelation in solution during agitation, then the chelation was promoted by heating at synthesis, and zeolite-A, zeolite-X and hydroxysodalite were synthesized.

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Stabilization of Mine Waste Using Paper Sludge Ash under Laboratory Condition

Cited by 5 publications

References 22 publications

Effects of Step-Wise Acid Leaching with HCl on Synthesis of Zeolitic Materials from Paper Sludge Ash

Effects of Step-Wise Acid Leaching with HCl on Synthesis of Zeolitic Materials from Paper Sludge Ash

Chemical Conversion of Paper Sludge Ash into Cation Exchanger Via Acid Leaching

Synthesis of Zeolite from Blast Furnace Slag Using Alkali Fusion with Addition of EDTA

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