A Comparison in Metal Leachability Between Phosphoric Acid and Ascorbic Acid Stabilised Ferrochrome Slag

2021 ◽  
Vol 47 (2) ◽  
pp. 207-215
Author(s):  
Thabo Falayi ◽  
Bolanle D. Ikotun
Keyword(s):  
Compressive Strength ◽  
Ascorbic Acid ◽  
Phosphoric Acid ◽  
Metal Ions ◽  
Unconfined Compressive Strength ◽  
Toxicity Characteristic Leaching Procedure ◽  
Ferrochrome Slag ◽  
Leaching Procedure ◽  
Phosphate Compounds

Ferrochrome (FeCr) slag was milled and stabilised with either ascorbic acid or phosphoric acid. The stabilised FeCr was then geopolymerised with 1 M KOH in order to obtain a monolith with at least an unconfined compressive strength of 1 MPa. The leachability of metals of the stabilised geopolymerised monoliths were then compared with the unstabilised geopolymerised monolith. Ascorbic acid stabilisation was only effective in Cr leaching reduction by 99.45% but was not effective on immobilisation of Fe, Zn, Ni and Mn. Ascorbic acid stabilisation was thought to proceed via the reduction of Cr(VI) species to insoluble Cr (III) species. Phosphate stabilisation reduced the leachability of Cr, Ni, Zn, Mn, Fe by 99.5%, 67.1%, 71.1%, 96.8% and 85.4% respectively. Phosphate stabilisation was thought to proceed via the formation of phosphate compounds of the metal ions in question. The phosphate stabilised FeCr slag leachability was within the allowable Toxicity Characteristic Leaching Procedure (TCLP) limits and its use is not detrimental to the environment.

Study on the Stabilization/Solidification of Lead-Contaminated Soil Using Alkali-Activated Cementing Materials with Rich-Silicon Materials

2017 ◽  
Vol 1142 ◽  
pp. 291-295
Author(s):  
Min Zhou ◽  
Shu Yan Wu ◽  
Yi Lv ◽  
Wei Xin Wang ◽  
Hao Bo Hou
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Rice Husk Ash ◽  
Cementitious Materials ◽  
Polluted Soil ◽  
Toxicity Characteristic Leaching Procedure ◽  
The Usa ◽  
Silicon Materials ◽  
Alkali Activated ◽  
Leaching Procedure

In this study, the stabilization/solidification of lead in soils using alkali-activated cementing materials with rich-silicon materials was investigated. The artificial Pb-polluted soil with 500mg/kg lead was treated using fly ash-, silica fume-and rice husk ash-based cementitious materials, respectively, at the dosages 25%. The effectiveness of treatment was assessed with unconfined compressive strength (UCS) and the toxicity characteristic leaching procedure (TCLP) after curing for 14 and 28 days. Overall, the UCS results showed that the UCS values are above the USA EPA’s recommended value of 0.35 MPa. The TCLP results indicated that the Pb concentrations extracted from soils amended with 25% cementitious materials after 14 and 28 days are near 0.25mg/L, far below 5mg/L (the TCLP regulatory limit). And the XRD results showed the immobilization of lead were due to the formation of PbSiO3, the sorption of C-S-H.

Experimental Research on Engineering Property of Heavy Metal-Contaminated Kaolinite

2011 ◽  
Vol 94-96 ◽  
pp. 1921-1929 ◽  
Author(s):  
Zhi Bin Liu ◽  
Xin Ma ◽  
Wen Long Dai
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Electrical Resistivity ◽  
Metal Ions ◽  
Unconfined Compressive Strength ◽  
Heavy Metal Ions ◽  
Engineering Property ◽  
Contamination Concentration ◽  
Expansion Capacity

Due to release and accumulation of industrial contaminants in natural soil in some regions, and the long-term interaction between leachate and clay which is adopted as isolation material of contaminants, the engineering property variation of clay soils after having been polluted by heavy metal ions gradually has drawn more and more attention of environmental geotechnical engineers. With relatively high chemical stability and low expansion coefficient kaolinite is widely distributed and usually used in engineering practice. In this research, Pb, Zn, and Cu-contaminated kaolinite specimens of controlled initial dry density and water content were manually prepared through static compaction. Then expansion capacity, unconfined compression, electrical resistivity and one-dimensional consolidation tests were conducted. It is found that the expansion capacity of contaminated kaolinite is influenced by the type and concentration of heavy metal ion. The unconfined compressive strength of heavy metal-contaminated kaolinite is decreased in a short period, but it may increase in a long term. Unconfined compressive strength of the same type of heavy metal-contaminated kaolinite will change with the contamination concentration. The electrical resistivity of kaolinite would be decreased when contaminated by heavy metal ions. The higher the contamination concentration is, the lower the electrical resistivity will be. All the compression indexes of heavy metal-contaminated kaolinite become lower than that of the clean kaolinite, and it also depends on both the type of heavy metal and contamination concentration. For the three types of heavy metal ions, Pb has the greatest influence on the engineering property of kaolinite, while the effects of Zn and Cu are quite similar.

scholarly journals Blended binder system with Incinerated Paper Ash (IPA) for Solidification/Stabilization (S/S)

2018 ◽  
Vol 7 (4.33) ◽  
pp. 491
Author(s):  
Mazni Mat Zin ◽  
Azyan Zafyrah Mohd Zahid ◽  
Noorashiekin Khalid ◽  
Nadia Zalikha Saifullizam ◽  
Wan Syarizawani Wan Chik ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Ordinary Portland Cement ◽  
Binder System ◽  
Sludge Treatment ◽  
Waste Sludge ◽  
New Material ◽  
The Impact ◽  
Leaching Procedure ◽  
Main Material

This research explored the potential to use IPA as a binder for the treatment of industrial waste sludge. Within the study, Incinerated Paper Ash (IPA) was used together Ordinary Portland Cement (OPC), a main material employed in solidification/stabilization (S/S) methodology to treated industrial ceramic sludge. The issues created by OPC in sustain the surroundings and cost force the new material must replace OPC as binder within the treatment methodology. The impact of the various IPA compositions within the system has been examined. The Unconfined Compressive Strength (UCS) and Toxicity Characteristic Leaching Procedure (TCLP) were used to assess the viability of IPA in sludge treatment once 28 days. The great result of compressive strength and decrease in heavy metals shows the potential of IPA in OPC replacement.   

Leachability of Metal Ions in TCLP Leachate of Solidified Petroleum Sludge

2013 ◽  
Vol 594-595 ◽  
pp. 1094-1098
Author(s):  
Asna Mohd Zain ◽  
Shaaban Md Ghazaly ◽  
Mahmud Hilmi
Keyword(s):  
Metal Ions ◽  
Ordinary Portland Cement ◽  
Rice Husk Ash ◽  
Toxicity Characteristic Leaching Procedure ◽  
Cement Ratio ◽  
Cement Replacement ◽  
Petroleum Sludge ◽  
Water To Cement Ratio ◽  
Leaching Medium ◽  
Leaching Procedure

Toxicity characteristic leaching procedure was executed on solidified petroleum sludge to investigate the metal ions release in leaching medium extractant fluid number 2, U.S.EPA SW-846 TCLP. Nine metal ions from solidified sludge in ordinary Portland cement were evaluated at water to cement ratio of 0.4 to 0.5 and incorporation of 5-15% cement replacement materials. Five cement replacement materials namely, rice husk ash, condense silica fume, activated carbon, fly ash and meta kaolin were selected for solidified sludge in the cement. Solidified sludge with cement replacement materials indicates minimum leachability of metal ions.

Rapid determination of soil unconfined compressive strength using reflectance spectroscopy

2021 ◽  
Vol 80 (5) ◽  
pp. 3923-3938
Author(s):  
Fatemeh Mousavi ◽  
Ehsan Abdi ◽  
Parviz Fatehi ◽  
Abbas Ghalandarzadeh ◽  
Hossein Ali Bahrami ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Rapid Determination ◽  
Reflectance Spectroscopy

scholarly journals Compression and Strain Predictive Models in Non-Structural Recycled Concretes Made from Construction and Demolition Wastes

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3177
Author(s):  
Evelio Teijón-López-Zuazo ◽  
Jorge López-Rebollo ◽  
Luis Javier Sánchez-Aparicio ◽  
Roberto Garcia-Martín ◽  
Diego Gonzalez-Aguilera
Keyword(s):  
Compressive Strength ◽  
Predictive Models ◽  
Unconfined Compressive Strength ◽  
Image Correlation ◽  
Peak Strain ◽  
Compression Tests ◽  
Maximum Peak ◽  
3D Digital Image Correlation ◽  
Granulometric Analysis ◽  
Physical And Chemical

This work aims to investigate different predictive models for estimating the unconfined compressive strength and the maximum peak strain of non-structural recycled concretes made up by ceramic and concrete wastes. The extensive experimental campaign carried out during this research includes granulometric analysis, physical and chemical analysis, and compression tests along with the use of the 3D digital image correlation as a method to estimate the maximum peak strain. The results obtained show that it is possible to accurately estimate the unconfined compressive strength for both types of concretes, as well as the maximum peak strain of concretes made up by ceramic waste. The peak strain for mixtures with concrete waste shows lower correlation values.

scholarly journals Characterization and Comparison Research on Composite of Alluvial Clayey Soil Modified with Fine Aggregates of Construction Waste and Fly Ash

2021 ◽  
Vol 28 (1) ◽  
pp. 83-95
Author(s):  
Qu Jili ◽  
Wang Junfeng ◽  
Batugin Andrian ◽  
Zhu Hao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Clayey Soil ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Construction Waste ◽  
Comparison Research ◽  
Fine Aggregates ◽  
Optimum Water Content

Abstract Fine aggregates of construction waste and fly ash were selected as additives to modify the characteristics of Shanghai clayey soil as a composite. The laboratory tests on consistency index, maximum dry density, and unconfined compressive strength were carried out mainly for the purpose of comparing the modifying effect on the composite from fine aggregates of construction waste with that from fly ash. It is mainly concluded from test results that the liquid and plastic limit of the composites increase with the content of two additives. But their maximum dry density all decreases with the additive content. However, fine aggregates of construction waste can increase the optimum water content of the composites, while fly ash on the contrary. Finally, although the two additive all can increase the unconfined compressive strength of composites, fly ash has better effect. The current conclusions are also compared with previous studies, which indicates that the current research results are not completely the same as those from other researchers.

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