No abstract

No abstract

a b s t r a c tIn ornamental rock industry large amounts of wastes in the form of powder have to be discarded. The reuse of ornamental rock-cutting waste to produce floor tiles for civil construction is described. The waste was added gradually up to 47.5 wt.%. The tile manufacturing route consisted of dry powder preparation, uniaxial pressing at 50 MPa, and sintering between 1190 and 1250 • C using a fast-firing cycle. The development of the microstructure was followed by XRD and SEM. The technological properties (linear shrinkage, apparent density, water absorption, and flexural strength) as function of the waste addition and firing temperature are investigated. The results revealed that the gradual replacement of Na-feldspar with rock-cutting waste accelerated liquid phase formation and thus sintering, resulting in denser microstructures. All tile pieces consist of mullite and partially dissolved quartz embedded in a glassy matrix. The technological properties were found to be influenced by the waste addition. It was also found that the replacement of Na-feldspar with rock-cutting waste as part of the flux system, in the range up to 47.5 wt.%, allows the production of enhanced floor tiles at lower firing temperatures.

The sanding process is important to the quality of wood products. Sanding reduces imperfections in wood surfaces and it is important to the final product and application of paints or varnishes. There are few studies about sanding in the literature and finding out the relationship between the input parameters (i.e., species of wood, grit size, abrasive) on the output parameters (i.e., roughness, force, pressure) will help to improve this process. This study analyzed the influence of input parameters as belt speed (cutting speed), grit size and pressure on the output parameters as surface roughness, cutting force (sanding force) and power consumption on cross-grain sanding of Eucalyptus grandis wood. The tests were performed with 3 types of grit sizes (80, 100 and 120 grit), 3 belt speeds (10, 11 and 12 m/s) and 2 pressures (219.89 and 283.44 g/cm²). The surface roughness was analyzed based on roughness average (Ra). Sanding efforts were analyzed by cutting force and power consumption. It was found that the 100 grit size provided the lowest cutting force. It was observed that the belt speed, pressure and grit size influenced the surface roughness, cutting force and power consumption. The best surface finishes were obtained in tests with higher pressure.

Large amounts of waste materials are discarded in the petroleum exploration industry. This work investigates the incorporation of solid petroleum waste (SPW) as a raw material into a clay body, replacing natural clay material by up to 30 wt%. Ceramic pieces were produced at temperatures varying from 700 to 1,100°C. The technological properties of the clay ceramic pieces (e.g., linear shrinkage, apparent density, water absorption, and compressive strength) have been determined. Development of the sintered microstructure was followed by scanning electron microscopy (SEM) and X-ray diffraction analyses. The leaching toxicity of the fired pieces has also been determined. The results showed that the SPW could be used in clay-based ceramics (clay bricks and roofing tiles), in the range up to 30 wt%, as a partial replacement for natural clay material. The leaching concentrations of Ag, As, Ba, Cd, Cr (total), Hg, and Pb of the fired pieces met the Brazilian regulatory requirements. These results suggest that the SPW can be valorized for manufacturing claybased ceramics, and at the same time, this application can help in reducing the environmental impacts of the petroleum exploration industry.