ImprimirIncorporation of waste in red ceramics
Two researches were developed in this area: one involving steel residues and the other sludge from a water treatment plant.
Water treatment plants (ETA) have been looking for recycling solutions for the waste generated in the water treatment process – this waste is called ETA sludge. Currently, the solutions are available in landfills or simply throw them in the sewer network. One sector that has enormous potential to contribute to the solution of environmental problems originating in the most diverse industrial processes is that of red ceramics.
In fact, studies reported in the literature have shown that it is possible to recycle industrial waste as constituents of ceramic masses for the manufacture of ceramic products for civil construction. The reuse of sludge from ETAs can be carried out with the incorporation of sludge in a red ceramic matrix. Through this mixture, specimens are made to carry out various tests, with the objective of establishing mixtures that enable the reuse of this sludge in the ceramic block matrix for the civil construction industry.
It is possible to measure after drying and firing, the following characteristics: color after firing, linear or volumetric retraction, modulus of tension or flexural rupture, water absorption, apparent porosity, apparent specific mass, loss to fire. COPASA – Companhia de Saneamento de Minas Gerais – headquartered in Belo Horizonte – MG, has a water treatment plant located in the municipality of Brumadinho-MG, the water intake from this system is in the lake originating in the Rio Manso basin. The average production of treated water is 3.80 m3 / s.
The water treatment plant is of the conventional type and produces 50m3 of sludge per day. To achieve the objectives of the present study, clay mixtures with different levels of sludge from ETA were used: 0%, 2%, 5% and 10%; in addition, mixtures of clay were made with 5% calcined sludge and 5% ground sludge. The specimens were formed by pressing and submitted to the following firing temperatures: 950ºC, 1000ºC and 1050ºC. The sludge samples were characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscopy and the specimens were observed by optical microscopy.
In the experimental conditions of this work it was concluded that the sludge added in the clay mass matrix contributed to the reduction of its plastic properties, that the Physical-Mechanical properties of the specimens made with the mixture of sludge and clay are influenced by the temperatures of firing and that the values of linear drying shrinkage, total linear shrinkage and linear shrinkage after firing, flexural rupture stress (TRF), loss to fire, are within the specified values for the manufacture of ceramic products red for use in construction.