Paper and cellulose wastes as raw materials for geopolymers

Reference Presenter Authors
04-104 Priscila Lemes Rachadel Eleutério, R.V.(UFSC); Hotza, D.(Federal University of Santa Catarina); Zanlorenzi, H.(Klabin); Rachadel, P.L.(Federal University of Santa Catarina); Geopolymers are alkali-activated aluminossilicate materials in which raw materials might be replaced by waste materials, being a green alternative to Portland cement. Fly ashes and dregs are waste materials from different production stages of paper and cellulose industry. Their composition present valorization potential by geopolymerization, since the first ones are an aluminosilicate and the second one is highly alkaline. In the present work, characterization of the raw materials and wastes as alternatives for metakaolin in geopolymer composition were carried out. The materials were characterized by XRD with Rietveld refinement, XRF, TGA and DLS, as well as by measuring compressive strength, porosity, density and water absorption. The influence of each waste material in the geopolymeric matrix was investigated. A relatively new approach to the field, differing amorphous content from bulk composition is proposed. The supposed potential from the waste materials is confirmed until metakaolin replacement of 10 wt% for fly ash and 50 wt% for dregs in geopolymeric pastes, presenting decreasing compressive strength from approximately 20 to 5 MPa in 28 days in both samples. The employment of the waste materials also resulted in porosity of approximately 50% and water absorption higher than 80 m%. The results are due to the characteristics of the waste materials, such as high crystallinity, organic matter and compositional and size particle heterogeneity. This study suggests that the waste generating company change processing conditions to produce fly ash and dregs characteristics in favor of geopolymerization, as well as suggestions for application in adsorption area.
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