Materials Science Forum Vols. 727-728

Abstract: In the production of white ceramic, the feldspar is used as flux that provides the manufacturing of products more dense and with low porosity. Although this is a raw material of great importance for white ceramic, the feldspar is a natural resource, therefore, non-renewable and your uncontrolled extraction can cause environmental problems. In this perspective, several scientific research is being carried out looking for alternatives to replace this product by other substances. The use of waste glass in partial replacement of feldspar in the production of ceramic body is extensively researched, because these materials present flux properties and reduces environmental impacts. Therefore, the purpose of this study is to verify the possibility of partial replacement of feldspar by waste flat glass in the formulation of the masses for white porcelain. For the research, feldspar and waste glass were characterized by the following techniques: chemical analysis, DTA, TG and infrared for possible comparison of the properties of these materials. The results demonstrated the possibility of utilization of waste flat glass in the formulation of ceramic bodies, since they have similar characteristics.

Abstract: To better study the mechanical behavior of red ceramic, the samples were degraded in salt spray equipment and exposed in environment. The salt spray equipment subjects the samples to conditions found by the sea, through the mix solutions of sodium chloride. The ceramic samples were prepared with up to 10% by mass of ornamental rock waste to dry and pressed into rectangular mold of steel. The materials were fired at temperatures of 650°C, 750°C and 850°C. After 90 days of degradation natural and 45 days in salt spray, ware analyzed the properties of ceramic material. The results of mechanical strength were compared using the Weibull distribution, before and after the degradation. Note that the material with ornamental rock waste raised the mechanical strength and didnt significantly changes the material properties after degradation.

Abstract: The vigorous industrialization of the modern world and the incorporation of new consumption habits of society made appears electronic waste. This work had as objective to collect and characterize vitreous residues originating from Cathode Ray Tubes or, popularly, "image tubes", identified for the acronym CRT, which integrate computers monitors that will be recycled in the production of handicrafts. For its characterization were used techniques: X-Ray Fluorescence, Granulometric Analysis, X-Ray Diffraction. After analyses it was observed that glasses of the screen and of the funnel presented different chemical compositions, being silicium oxide (SiO₂) the component of larger percentage in these glasses, 59.89% and 48.63%, for screen and funnel, respectively. Funnel presented 29.47% of lead oxide (PbO) while this oxide is absent in the screen. Screen presents significant amounts of barium oxide (10.75%) and strontium oxide (7.71%). Vitreous samples X-ray diffractions of residues of the funnel and the screen are to each other similar, presenting an amorphous band that indicates silica presence, with absence of crystalline phases. Through the presented results can be concluded that computer monitors CRTs has potential for be recycled, because present great amounts of SiO₂, oxide that forms the vitreous net.

Abstract: The present work studied the adsorption of ions of iron and manganese of the effluent from coal acid mine drainage (AMD), located in South of the Santa Catarina using for this purpose type 4A zeolite. Were tested the Langmuir adsorption isothermal model. Tests of adsorption of heavy metals were performed by varying the adsorption time and the ratio of the volume of effluent and the amount of adsorbent. The results showed the efficiency of kinetic adsorption of iron and manganese ions by the zeolite.

Abstract: A great amount of granite waste and steel slag is generated daily in Brazil, being those constituted mainly by SiO₂ and CaO, respectively. The objective of this work was to characterize the material formed after melting and cooling of the mixture of granite waste and LD steel slag, with basicity (CaO/SiO₂) of 1.0, aiming to evaluate the technical feasibility of this to the Portland cement production. Two samples were prepared and melted. After the melting of the mixture, one sample was cooled in water and another in the furnace. The samples characterization was carried out through X-ray diffraction and scanning electron microscopy. The results showed that the new material formed presented amorphous state, to the samples cooled in water and akermanite and gehlenite phases, considered ideals for the hydraulic activity of the slags, in the sample cooled in the furnace. Therefore, the mixture of those two wastes can be a new alternative for the use of both, allied to the decrease of the environmental impact.

Abstract: Tanning industries generates large quantities of solid wastes containing chromium compounds with characteristics of high-polluting and hazardous conditions. However, these wastes are a potential source of chromium which could be used by the glass and ceramic enamels industries. In this study the properties of a calcined tannery sludge containing chromium compounds was investigated in order to evaluate the potential of using this powder as a suitable and cheap green colorant for the glass manufacturing. X-ray diffraction (XRD), chemical (XRF) and thermal (DTA/TG) analyses were used to determine the physical and chemical characteristics of tannery sludge. Colorimetric method using diphenylcarbazide were conducted to determinate the Cr (VI) concentration in the samples. Soda-lime glass containing calcined tannery sludge was prepared by melting at 1550°C. The results showed that the calcined tannery sludge has a favorable behavior to be used as an alternative source of chromium for the glass manufacturing.

Abstract: The advantage of the incorporation of tire rubber powder and rice husk ash in the polymer compound is mainly due to the reduction of the products cost, as well as improving the essential properties for a great processing of the material, for example, its flow into a hole of a thin wall mold. The rice husk ash can replaces the carbon black in the new products, contributing with the improvement of the environment and the economy of the society. Main objectives of this work are: enhance the applications of the ashes from the rice husk and the waste from the tire rubber, as well as, study new methods of recycling of polymeric wastes, to incorporate an aggregated value to the recycled materials as well as obtaining compounds or nanocompounds materials.

Abstract: Studies of degradation have verified that the decomposition of some quaternary ammonium salts can begin to be significant at the temperature of about 180 ° C and like most thermoplastics are processed at least around this temperature, the thermal stability of the salt in clay should always be considered. Some salts are more stable than others, being necessary to study the degradation mechanisms of each case. In this work, four quaternary ammonium salts were characterized by differential scanning calorimetry (DSC) and thermogravimetry (TG). The results of DSC and TG showed that the salts based chloride (Cl^-) anion begin to degrade at similar temperatures, while the salt based bromide (Br^-) anion degrades at higher temperature. Subsequently, a quaternary ammonium salt was chosen to be used in organoclays, depending on its chemical structure and its thermal behavior.

Abstract: The organoclays are derived from bentonite clays treated in aqueous solution with surfactants, which are incorporated into the interlayer surface of clays, covering them with an organic layer; so, the naturally hydrophilic clay becomes hydrophobic. This paper proposes a study to find the dispersant media (diesel, paraffin or ester) which is more suitable for use in fluids, using the bentonite clay Cloisite Na +, treated with ionic surfactants Praepagen HY and Praepagen WB. The organoclay obtained was characterized by X-ray diffraction, and we measured the apparent viscosity and plastic dispersions. We observed the importance of the type of surfactant and dispersant amid to obtain organoclays for non-aqueous drilling fluids with the dispersants that meet existing specifications for drilling oil wells.

Abstract: The State of Paraíba has large reserves of bentonite clays, mainly in the District of Boa Vista. New occurrences were recently discovered in the Districts of Pedra Lavrada and Cubatí, Paraíba, Brazil, creating great expectations for further expansion of reserves for industrial production. The use of nonionic surfactants is replacing the traditional ionic surfactants, among others, by its high resistance potential to thermal degradation. The objective is the development organoclays from Pedra Lavrada District PB, Brazil, clays, by adding non-ionic surfactants. The bentonites were organofilized and then characterized by X-ray diffraction (XRD), thermal analysis (TGA and DTA) and Foster swelling, seeking the most appropriate choice of surfactants to the diesel organic dispersing medium. The results showed that incorporation of surfactants used in the clay interlayer spacing increased significantly.