Study of electric arc furnace steel waste efflorescence formation incorporated in red ceramics

Reference	Presenter	Authors (Institution)	Abstract
16-072	Adriano Alves Rabelo	Barbosa, A.C.(Universidade Federal do Sul e Sudeste do Pará); Luz, D.S.(Universidade Federal do Sul e Sudeste do Para); Sousa, R.C.(Universidade Federal do Sul e Sudeste do Pará); Fagury Neto, E.(Universidade Federal do Sul e Sudeste do Pará); Rabelo, A.A.(Universidade Federal do Sul e Sudeste do Pará);	The soluble salts are the cause of the formation of the efflorescence and main agents of the degradation of the ceramic materials of construction. This type of manifestation besides affecting aesthetically the internal and external environment, causes problems of insalubrity and contribute in the acceleration of the deterioration of the contaminated construction materials. Steel production is bound to accumulate a large amount of solid waste, among which are the electric arc furnace slag and the dedusting powder generated during the steel fabrication. In this work, the formation of efflorescence in red ceramics with 3 to 12 wt% additions of steel slag from the electric arc furnace, and additions of 5 to 35 wt% of dedusting powder in the clay mass were studied. Test pieces of 60 x 20 x 4 mm were prepared, pressed at 55 MPa in a uniaxial press, which were then calcined at 400 ºC in a muffle oven for two hours. The sintering temperatures used were 800, 850 and 900 ° C 2 hours plateau. After burning, water absorption, apparent porosity, apparent density and linear retraction were characterized by the Archimedes method. For the efflorescence test, 80% of the specimen length was immersed in distilled water for one week, which was subsequently kiln-drying at 110 ° C for 24 h to accelerate the process of formation of the efflorescence. A microstructural characterization was performed by scanning electron microscopy and quantification of the salts through electrical conduction of the samples. The samples were visually inspected and the efflorescence was not detected with the naked eye with the additions of slag, unlike the dedusting powder, in which the formations of the efflorescences at the extremities of the test bodies were very noticeable.
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