Kaolin mining waste to produce geopolymers: Physicomechanical properties and susceptibility to efflorescence formation

Case Studies in Construction Materials

Márcio S. Barata¹  Erich D. Rodríguez²  Márlon A. Longhi³  Ana P. Kirchheim⁴  Zuhua Zhang⁵  Sandro M. Torres⁶ 

[1] Advanced Civil Engineering Materials and Application Technology of Hunan Province, College of Civil Engineering, Hunan University, Changsha 410082, PR China;Corresponding author.;Department of Civil Engineering, Post-Graduate Program in Civil Engineering: Construction and infrastructure, Universidade Federal do Rio Grande do Sul (NORIE/UFRGS), Porto Alegre, RS, Brazil;Department of Mechanical Engineering, Universidade Federal da Paraíba, João Pessoal, PB, Brazil;Department of Structures and Civil Construction. Center of Technology (CT), Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil;;Key Laboratory for Green &

关键词: Calcinated kaolin;    Mining waste;    Alkali-activated materials;    Geopolymers;    Waste valorization;    Durability;   

DOI  :  

来源: DOAJ

【 摘 要 】

The kaolin mining waste (KW) is a residue generated during the purification process of extracting high purity kaolin used in different industries. KW is mainly constituted by kaolinite-rich clay and other secondary minerals such as anatase and quartz. With the appropriated and controlled process, calcined kaolin mining waste (CKW). It can be thermally activated by calcination to obtain a highly reactive metakaolinite rich material, which exhibits interesting pozzolanic properties. According to its chemical composition and high reactivity, this material is used as an aluminosilicate precursor in the production of geopolymers. One of the negative effects may be the formation of efflorescence. This paper evaluated geopolymer produced with CKW at different activation conditions (alkali concentration and sodium silicate content). The leaching of alkalis was studied through the development of efflorescence on the surface of hardened samples exposed to efflorescence formation conditions (contact with air and water). The results indicated that a larger activator provided a higher compressive strength and reduced the capillary absorption and the efflorescence formation. The data showed that the efflorescence formation can be appropriately controlled by adjusting the mix design parameters, especially the sodium silicate content.

【 授权许可】

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