Estimation of gypsum hemihydrate content in recycled gypsums derived from gypsum boards

Inazumi, Shinya; Sano, Hiroaki; Yamada, Mikio

doi:10.1007/s10163-014-0319-x

Cited by 9 publications

(5 citation statements)

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“…Durante a calcinação do resíduo de gesso passa por uma desidratação em estufa a uma determinada temperatura e por um período de tempo para obtenção do gesso reciclado (hemihidrato) [14]. Os produtos da desidratação do gesso podem ser hemihidrato e anidritas, vários fatores podem influenciar nas reações como o tipo de gesso e condições ambientais resultando em variações nas temperaturas de transição [15].…”

Section: Introductionunclassified

Avaliação dos parâmetros de calcinação do resíduo de gesso nas propriedades do gesso reciclado

et al. 2021

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RESUMO As atividades industriais têm contribuído com a geração de resíduos de gesso, logo o alto volume e a destinação inapropriada contribuem com os problemas ambientais, além de representar desperdício de material na construção civil. O objetivo do trabalho foi caracterizar o resíduo de gesso e avaliar a influência de parâmetros como granulometria, temperatura e tempo de calcinação nas propriedades do gesso reciclado, buscando a redução dos resíduos e obtenção de melhores propriedades do produto final com a utilização de 100% de gesso reciclado. O resíduo de gesso foi beneficiado, caracterizado e separado em três diferentes granulometrias: peneira ABNT nº 200 (0,075 mm); ASTM nº 50 (0,3 mm) e ABNT nº 10 (2,0 mm). Em seguida calcinados nas temperaturas de 130, 136, 150 e 170ºC durante 1, 2, 4, 6, 8, 17 e 24h. Foi analisada no gesso reciclado a sua trabalhabilidade, calor de hidratação, propriedades mecânicas, caracterização mineralógica e morfologia. O gesso reciclado teve influência nas suas propriedades nos parâmetros avaliados, além da presença de impurezas. As principais fases formadas no gesso reciclado foram afetadas pelo tempo de calcinação: o sulfato de cálcio hemihidratado, sulfato de cálcio dihidratado, anidrita e calcita. A trabalhabilidade não mostrou uma tendência clara de comportamento independente da granulometria, tempo e temperatura de calcinação. Os melhores resultados para a resistência compressão foram obtidos na temperatura de 136ºC (17h) e 150ºC (8h). O gesso reciclado apresentou uma dureza média de 12,71N·mm-². A reciclagem do resíduo de gesso pode contribuir com a redução dos resíduos e possibilitar na construção civil a utilização de novas tecnologias.

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Section: Introductionunclassified

Avaliação dos parâmetros de calcinação do resíduo de gesso nas propriedades do gesso reciclado

et al. 2021

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“…However, it is feasible to develop a new technology to reuse these wastes in further applications due to limited space and contaminating groundwater sources in addition to the environmental regulation of some countries. It has been reported that gypsum plasterboard wastes can be recycled in a sequential process by crushing, separating, and burning to transform the dihydrate into the hemihydrate phase [17]. According to their report, it is useful as geomaterial or ground improvement material due to its effectiveness in many engineering and economic aspects [17].…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that gypsum plasterboard wastes can be recycled in a sequential process by crushing, separating, and burning to transform the dihydrate into the hemihydrate phase [17]. According to their report, it is useful as geomaterial or ground improvement material due to its effectiveness in many engineering and economic aspects [17]. e conversion of gypsum into a recycled product has been interesting for many researchers due to its reaction reversibility, cycle-ability, stability, environmental safety, nontoxicity, and sustainability [4,11,18,19,22].…”

Section: Introductionmentioning

confidence: 99%

The Mechanism of the First Hydration-Dehydration Cycle of Pure α- and β-CaSO₄•0.5H₂O

Zeitoun

Pritzel

Sakalli

et al. 2020

Advances in Materials Science and Engineering

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The objective of this research was to understand the dehydration mechanism of technical dihydrate and the variation of the physical properties of β-hemihydrate after the first hydration-dehydration process. In this study, the recycling mechanism of different hemihydrate types as raw material was investigated. The influence of the first hydration-dehydration process on the hydration rate, microstructure, and mechanical properties of recycled hemihydrate were characterized by differential calorimetric analysis (DCA), calcium ion-selective electrode (Ca2+-ISE), conductivity, particle size distribution (PSD), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results showed that the formed hemihydrate after the first hydration-dehydration process differs in its properties than the unrecycled hemihydrate in some characteristics such as the morphological structure, number of surface, and side defects due to the grinding process after the first hydration step. In addition to the grinding step, the calcination process was responsible for increasing the number of defects on the crystal surface, which leads to a change in setting time and the microstructure of the recycled hemihydrate. Therefore, after the 1st reaction cycle of β-HH, the compressive strength decreases due to a decrease in the hemihydrate crystal size, an increase in the surface area, and an increase in the amount of water required to perform the hydration reaction. The obtained hemihydrate after the first hydration-dehydration process was in β form due to the applied calcination process after the first cycle.

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“…The matrix soil of fluidization treated soil (A) has been allowed the mixing of particle size 74μm or more fine sand. Some fundamental properties for the fluidization treated soils (A) and (B) have been mentioned by Inazumi et al [2], [3].…”

Section: Overview Of the Fluidized Processing Soilmentioning

confidence: 99%

“…At the same time, an animation of the flow test is also taken. Some characteristic of the fluidization treated soils (A) and (B) is shown in Table 2 [2], [3]. Table 2 The In Figs.…”

Section: Understanding and Evaluation Of Flow-ability By The Flow Testmentioning

confidence: 99%

Evaluation of Flow-Ability on Fluidization Treated Soils Based on Flow Analysis by MPS Method

Inazumi¹

2017

geomate

Self Cite

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ABSTRACT:Recently, fluidization treated soils have come to be used as landfill materials or fillers in such landfill of underground space in Japan. However, the design and construction of the fluidization treated soils at present is based only on empirical knowledge. Therefore, taking into account the findings based on a theory is thought to be useful. In this study, it has evaluated the flow-ability of the fluidization treated soils based on the flow analysis by the MPS method and the experimental evaluation. Favorable results have been obtained in the numerical flow analysis by using the Bingham model to the MPS method. In addition, the authors have developed a fluidization treated soil with increased flow-ability (super-fluidization treated soil). It has evaluated from two aspects of mechanical properties and flow properties of the high flow of the super-fluidization treated soil. The flow properties show that it has a high flow-ability than the fluidization treated soil.

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Estimation of gypsum hemihydrate content in recycled gypsums derived from gypsum boards

Cited by 9 publications

References 3 publications

Avaliação dos parâmetros de calcinação do resíduo de gesso nas propriedades do gesso reciclado

Avaliação dos parâmetros de calcinação do resíduo de gesso nas propriedades do gesso reciclado

The Mechanism of the First Hydration-Dehydration Cycle of Pure α- and β-CaSO₄•0.5H₂O

Evaluation of Flow-Ability on Fluidization Treated Soils Based on Flow Analysis by MPS Method

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Estimation of gypsum hemihydrate content in recycled gypsums derived from gypsum boards

Cited by 9 publications

References 3 publications

Avaliação dos parâmetros de calcinação do resíduo de gesso nas propriedades do gesso reciclado

Avaliação dos parâmetros de calcinação do resíduo de gesso nas propriedades do gesso reciclado

The Mechanism of the First Hydration-Dehydration Cycle of Pure α- and β-CaSO4•0.5H2O

Evaluation of Flow-Ability on Fluidization Treated Soils Based on Flow Analysis by MPS Method

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The Mechanism of the First Hydration-Dehydration Cycle of Pure α- and β-CaSO₄•0.5H₂O