Reuse of the soda sludge dealt with water washing as a supplementary material for the synthesis of clinker binders. (1st May 2021)

• Record Type: Journal Article
• Authors: Wang, Qiang; Li, Jingjing; Zhang, Jiakang; Wu, Peng; Lyu, Xianjun; Hu, Shugang; Qiu, Jun; Liu, Xiaodong; Yu, Hongguan
• Is Part Of: Journal of cleaner production. Volume 295(2021)
• Publication Date: 2021-05-01
• Subjects: Soda sludge -- Water washing -- Clinker binders -- Hydration -- Strength development; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2021.126433
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Doubling of the demand for clinker binders has also resulted in a corresponding increase in the need for calcareous materials. Soda sludge, a calcareous solid residue generated during the production of sodium carbonate, causes serious environmental harm. In this study, soda sludge was used as the calcareous material to synthesize clinker binders, where the effect of temperature and times of water washing on chloride ions (Cl − ) in soda sludge was investigated. Four clinker binders were synthesized at the same clinker coefficients. The residual calcium oxide, the phases of these clinker binders, and the effect of Cl − on their strength development and hydration were also investigated. The results showed that the soda sludge dealt with water washing five times at 80 °C, with a minimum Cl − concentration of 0.26 wt%, The optimum temperature to prepare clinker binders was 1450 °C. When the Cl − content in the soda sludge decreased from 6.4 to 0.26 wt%, the fracture and crush strengths of the clinker binders synthesized with 27.00 wt% soda sludge rose from 4.3 to 26.9 MPa to 7.2 and 52.7 MPa at 30 d, respectively; this was equivalent to a 52.5 grade clinker binder. The phases of the clinker binders transformed from alinite, calcium aluminate chloride, and calcium silicate chloride to tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite. The hydration phases of the clinker binders transformed from calcium aluminate chloride hydrates and calcium chloride silicate sulfate to calcium silicates hydrates and portlandite. This study evaluates an environmentally friendly approach to reuse soda sludge, and concurrently offers a novel supplementary material to synthesize clinker binders. Highlights: Soda sludge is a promising material for the synthesis of clinker binders. The Cl − in soda sludge is reduced from 6.4 to 0.26 wt% by water washing. The phases containing Cl − disappear in the clinker binders and its hydration. The fracture and crush strengths of the clinker binders are improved. It is helpful to the disposal of soda sludge and the material supply of clinker binders.