Toward more sustainable hydraulic binders: controlling calcium sulfate phase selection via specific additives
Bassanite (calcium sulfate hemihydrate) is one of the most extensively used inorganic binders in construction applications. Current industrial processes for the large-scale production of the mineral rely almost exclusively on the thermal dehydration of gypsum (calcium sulfate dihydrate), which consu...
| Autores: | , , , , , , , |
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| Formato: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2023 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/348044 |
| Acesso em linha: | http://hdl.handle.net/10261/348044 |
| Access Level: | acceso abierto |
| Palavra-chave: | Additive-controlled crystallization Bassanite Calcium sulfate Hydraulic binders Specific ion effects |
| Resumo: | Bassanite (calcium sulfate hemihydrate) is one of the most extensively used inorganic binders in construction applications. Current industrial processes for the large-scale production of the mineral rely almost exclusively on the thermal dehydration of gypsum (calcium sulfate dihydrate), which consumes considerable amounts of energy. Here, we show that phase-pure bassanite can be obtained in high quantities by spontaneous precipitation from supersaturated solutions at moderate temperatures, where gypsum usually forms as a predominant solid phase. Key to control over phase selection is the presence of specific additives during crystallization, which carry functional groups for binding onto calcium sulfate surfaces as well as additional moieties that withdraw water in the local microenvironment. Some of the investigated additives allowed bassanite to be recovered in large amounts at temperatures as low as 40 °C and added concentrations of only 0.1 M or even less. The concepts described in this work pave the way toward alternative approaches, enabling a less energy-intensive and thus more sustainable production of bassanite for use in construction and other applied systems. |
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