Preparation of load-bearing building materials from autoclaved phosphogypsum

Yang, Jiakuan; Liu, Wanchao; Zhang, Lili; Xiao, Bo

doi:10.1016/j.conbuildmat.2008.02.011

Cited by 257 publications

(92 citation statements)

References 8 publications

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“…Nowadays a number of researches are focused on finding new uses of PG: a) agricultural fertilizer or for soil stabilization amendments (6)(7)(8); b) cement industry as a setting regulator in place of natural gypsum (4,9,10), in the gypsum industry to make gypsum plaster (4,11,12), as mineralizer in the burning Portland cement clinker (PCC) (13), as raw material in the raw mix of cement (14)(15)(16) and in other binders materials (17)(18)(19)(20).…”

Section: Introductionmentioning

confidence: 99%

Thermal dehydration kinetics of phosphogypsum

López¹,

Tayibi²,

García‐Díaz³

2015

Mater. construcc.

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ABSTRACT:Phsophogypsum is a by-product from the processing phosphate rock. Before the use of it in cement industry such as setting regulator is necessary a study of dehydration reaction of phosphogypsum to avoid the false setting during the milling.The aim is to study the thermal behavior of two different phosphogypsum sources (Spain and Tunisia) under non-isothermal conditions in argon atmosphere by using Thermo-Gravimetriy, Differential Thermal Analysis (TG-DTA) and Differential Scanning Calorimetry (DSC).DSC experiments were carried out at temperatures ranging from ambient to 350 °C at different heating rates. The temperatures of conversion from gypsum to hemihydrate and anhydrite states and heat of dehydration were determined. Various methods were used to analyze the DSC data for reaction kinetics determination. The activation energy and frequency factor were calculated for dehydration of phosphogypsum. Activation energy values of the main dehydration reaction of phosphogypsum were calculated to be approximately 61-118 kJ/mol. RESUMEN:Estudio cinético de la deshidratación térmica del fosfoyeso. El fosfoyeso es un subproducto procedente del procesado de la roca fosfato. Una de las posibles vías de reutilización y revalorización es su uso como regulador del fraguado en la industria cementera. Debido a los posibles problemas de falso fraguado asociado a los procesos de deshidratación que tienen lugar durante la molienda del cemento, esta investigación estudió el comportamiento térmico, bajo condiciones no-isotérmicas en atmósfera de argón, de dos fosfoyesos, mediante TG-DTA y DSC.Los ensayos de DSC se realizaron hasta los 350 °C a diferentes velocidades de calentamiento. La temperatura de conversión del yeso a las formas de hemihidrato y anhidrita y el calor de hidratación fueron determinados.Las cinéticas de reacción fueron obtenidas analizando los datos de DSC mediante varios métodos. Se calculó la energía de activación y el factor de frecuencia para las reacciones de deshidratación del subproducto. Los valores de energía de activación de las principales reacciones de deshidratación del fosfoyeso fueron obtenidos, aproximadamente 61-118 kJ/mol.

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Section: Introductionmentioning

confidence: 99%

Thermal dehydration kinetics of phosphogypsum

López¹,

Tayibi²,

García‐Díaz³

2015

Mater. construcc.

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“…En el caso del PG, el incremento de la demanda internacional de fertilizantes promueve la producción de grandes cantidades de este residuo en todo el mundo (100-280 Mt por año) (1). La mayor parte de estos residuos se almacenan en balsas sin ningún tratamiento previo, lo que representa una fuente potencial de una compleja contaminación ambiental.…”

Section: Introductionunclassified

Valorización de fosfoyeso como material de construcción: Aspectos radiológicos

Tayibi¹,

Gascó²,

Navarro³

et al. 2010

Mater. construcc.

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“…Therefore, the crystal morphology of α-CSH is long-rod-like or needlelike. [34,35] Figure 5 shows crystal morphology of the prepared α-CSHs when different concentrations of maleic acid, succinic acid or tartaric acid are added. All the α-CSHs prepared under the different conditions have hexagon prism shape.…”

Section: Effect Of Modifier On the Morphology Of α-Cshmentioning

confidence: 99%

“…With the rapid development of phosphate fertilizer industry in China, more than 55 million tons of PG were discharged annually. [1] Nevertheless, the utilization ratio of PG in China is approximately 20.0% and large amounts of PG were piled up without any treatment. [2] The disposal and reutilization of PG have been one of the most critical problems for the enterprises and government due to considerable land occupation and serious environmental issues including groundwater pollution and soil contamination.…”

Section: Introductionmentioning

confidence: 99%

Morphology‐Controlled Preparation of α‐Calcium Sulfate Hemihydrate from Phosphogypsum by Semi‐Liquid Method

Chen

et al. 2017

Crystal Research and Technology

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Phosphogypsum (PG), a by-product of phosphoric acid industry, causes environmental issues. In this paper, PG was effectively transformed into alpha-calcium sulfate hemihydrate (ɑ-CSH) via a semi-liquid method. The phase evolution and the effects of different organic acids and pH values on crystal morphology of the α-CSH were investigated by SEM, XRD and EDS. The properties of the prepared α-CSH with different aspect ratio were also compared. The results indicate that PG can be successfully transformed into α-CSH by the semi-liquid method at 140°C for 3.0 h. The morphology of the produced α-CSH is significantly influenced by the concentrations of organic acid and pH value. α-CSH crystal with well-morphology is obtained under the condition of 0.1 wt.% maleic acid and pH = 7.0. The obtained α-CSH with uniform particle size has the aspect ratio of 1.2. The 2 h and 3 d bending/compressive strengths of the hardened paste prepared from the α-CSH reach 6.4/20.6 MPa and 10.5/43.7 MPa respectively, which are comparable to those of the commercial α-CSH. Moreover, the lower aspect ratio of ɑ-CSH results in more compact microstructure and higher mechanical strengths of the hardened paste.

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Preparation of load-bearing building materials from autoclaved phosphogypsum

Cited by 257 publications

References 8 publications

Thermal dehydration kinetics of phosphogypsum

Thermal dehydration kinetics of phosphogypsum

Valorización de fosfoyeso como material de construcción: Aspectos radiológicos

Morphology‐Controlled Preparation of α‐Calcium Sulfate Hemihydrate from Phosphogypsum by Semi‐Liquid Method

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