Evaluation of S/S Process of Tannery Waste in Cement by Structural and Mechanical Analysis

Pinto, Carolina A.; Dweck, Jo; Sansalone, John J.; Cartledge, Frank K.; Hamassaki, Luiz Tsuguio; Valenzuela‐Díaz, Francisco Rolando; Albanez, N.E.K.; Büchler, Pedro Maurício

doi:10.4028/www.scientific.net/msf.660-661.1130

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…According to the results obtained by the authors, the addition of potassium dichromate promoted significant reductions in resistance values, attributed to inhibition and delay of cement hydration. Pinto et al, [29] in their study on stabilization by solidification of tannery residue, also observed that the increase in the were also verified by por Costa et al, [31] and according to the authors, this behavior refers to the conversion of dichromate ions into chromate ions, influenced by the pH change of the solution promoted by the addition of cement. For the construction of the analytical curve, the absorbance values of the verified solutions for the wavelength of 372 nm were considered.…”

Section: Resultsmentioning

confidence: 66%

“…As an example of a porosity reducer, bentonite can be cited, which increases in volume when hydrating, obstructing the passage of water through the pores or cracks in the cement matrix [32]. Clays can also be added to the paste to favor the immobilization process, since they can adsorb the metals present in the residues and aid in the mechanical resistance, occupying empty spaces between the hydrated cement components [29]. The association of binders, such as lime and cement, can favor the encapsulation of waste.…”

Section: Resultsmentioning

confidence: 99%

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Assessment of the Integrity and Retention of Chromium (VI) in Portland Cement Pastes

Lobato¹,

Batista²,

Encarnação³

et al. 2021

ACES

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Chromium is a heavy metal used for various applications such as in the manufacture of stainless steels, in chemicals for wood treatment, in tanneries, and in the refractory industry. The main problem associated with the use of chromium in these activities is the considerable volume of contaminated effluent that requires treatment, mainly due to its high mobility and toxicity in its hexavalent form. Immobilization methods arise as an efficient solution for the treatment of these wastes through converting them into inert and stable materials. The present paper aims to investigate Portland cement II's paste properties with potassium dichromate addition in order to verify the chromium immobilization process. Analyses of moisture content, water absorption, axial compressive strength, and solubilization were done in samples at 7 and 28 days with 0%; 0.5%; 1.05; 1.5%; 2.0% and 2.5% potassium dichromate addition. The results showed the influence of this salt in cement hydration reactions, damaging the mechanical behavior and the water absorption capability of the material produced. In the solubilization test, all compositions had >99% efficiency of chromium immobilization in both ages of hydration, thus demonstrating the capability of a cementitious matrix to stabilize this metal.

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Section: Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 99%

Assessment of the Integrity and Retention of Chromium (VI) in Portland Cement Pastes

Lobato¹,

Batista²,

Encarnação³

et al. 2021

ACES

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“…As características do resíduo, tais como o seu conteúdo orgânico, conteúdo inorgânico, viscosidade, tamanho e distribuição das partículas podem afetar a qualidade do produto final solidificado. A influência de um mesmo composto dentro da matriz de S/E pode MINOCHA;JAIN;VERMA, 2003;CHEN et al, 2009;PINTO et al, 2010; HEKAL et al, 2011), obtendo como resultado a redução da concentração destes metais e sua capacidade tóxica. Esta técnica deve imobilizar o resíduo perigoso e não alterar as características do cimento(DWECK et al, 2000a).Nos processos de S/E com cimento, o mecanismo de fixação dos metais pesados, em muitas vezes, é através da precipitação química de espécies de baixa solubilidade(CHEN et al, 2009), que está ligada ao pH do sistema.…”

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“…A formulação contendo rejeito apresentou um aumento de 7% na resistência a compressão em comparação a argamassa controle.No Brasil não há uma legislação específica sobre materiais S/E, para avaliação do processo de S/E das formulações quanto a resistência à compressão, utilizou-se como referência alguns modelos já existentes, que constam na Tabela 4.10, utilizados também por outros autores. Detectou-se que todos os resultados obtidos de resistência à compressão viabilizam a aplicação do processo de S/E sem restrição, valores acima de 0,34 MPa.Em seu trabalho,Pinto et al, (2010) avaliaram o processo de S/E em cimento Portland com adição de resíduo contendo cromo. A presença do resíduo diminuiu a resistência à compressão, efeito oposto foi detectado com adição de aditivos (argilas) nas amostras, comparado a amostra controle.…”

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Solidificação e estabilização de resíduos de catalisadores contendo níquel e alumínio em cimento Portland.

Melchert¹

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In polyols production two catalyst wastes (RNi and RAI) are obtained, which are considered hazardous, due to their respective high nickel and aluminum contents. This Thesis presents the study of the simultaneous solidification/stabilization of both wastes with type II Portland cement (CPII), in order to avoid environmental impacts and to check the possibility of the use of the solidified products as structural elements. The experimental research performed for this study consisted of non-conventional differential thermal analysis, thermogravimetric analysis, X ray diffraction, X ray fluorescence, leaching and compressive strength tests. The analysis of the first stages of the cement hydration, as well as of samples hydrated at different ages during the first 28 days of hydration, allowed evaluate the effects of the presence of the wastes on the process, identify the steps where the changes occur and have a quantitative information about the main cement hydrated phases. Pastes with water/cement ratio equal to 0.5 were used, into which different amounts of each waste were added. In the early stages of cement hydration retarding and accelerating effects occur, respectively due to RNi and RAl presence. During the simultaneous use of the two waste catalysts for their solidification/stabilization in cement, there is a synergic effect, which allows better operating conditions than when each waste is solidified separately. The leaching tests done for solidified pastes and mortars, after the standard evaluation period of 28 days of solidification, presented values for the final concentration of Ni and Al below accepted limits, indicating that the simultaneous solidification process attends environmental legislation, as well as eliminates the original environmental impact of the wastes. Pastes and mortars analyzed also after 28 days by compressive strength tests, presented acceptable results for the possible use of the solidified products in construction industry.

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The durability of slag and tannery sludge based geopolymer corroded by acid and base solutions

Bie,

Yin,

Chen

2024

Construction and Building Materials

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Evaluation of S/S Process of Tannery Waste in Cement by Structural and Mechanical Analysis

Cited by 5 publications

References 20 publications

Assessment of the Integrity and Retention of Chromium (VI) in Portland Cement Pastes

Assessment of the Integrity and Retention of Chromium (VI) in Portland Cement Pastes

Solidificação e estabilização de resíduos de catalisadores contendo níquel e alumínio em cimento Portland.

The durability of slag and tannery sludge based geopolymer corroded by acid and base solutions

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