Tania Maria Basegio

Environmental and technical aspects of the utilisation of tannery sludge as a raw material for clay products

This paper is a report on the results of a feasibility study on the immobilisation of tannery sludge by producing a ceramic product. The main purpose of this work was to test the clays used in the manufacture of a ceramic that could incorporate tannery sludge. The raw materials, tannery sludge and clay, were mixed together in different proportions. The ceramic specimens were characterised with respect to water absorption, porosity, linear shrinkage and transverse rupture strength. Leaching tests, in accord with the Brazilian and German regulations, were done on ceramic bodies made with different additions of sludge. In order to evaluate the possibility of air contamination during the firing process, preliminary studies of air emissions were carried out The mechanical properties of the samples evaluated were similar to those specified for ceramic bricks. All the leaching tests have shown that the main sludge contaminant i.e. chromium, could be immobilised within a finished ceramic product. The studies of air emissions have shown that zinc and chlorine are mainly collected from gas emissions and hence are not immobilised by the ceramic system. The study shows that the properties of the ceramic materials produced are acceptable for applications such as bricks for the building industry.

Vitrification: an alternative to minimize environmental impact caused by leather industry wastes.

The main purpose of this work was the investigation of the immobilization of chromium ion present in the ash from the incineration of chromium-tanned leather shavings (ACS) by means of vitrified ceramic bodies. To achieve the immobilization samples were initially produced adding soda-lime glass to ACS. After that, new formulations were produced with the addition of pure oxides, TiO(2) and MgO, to the soda-lime glass and ACS sample. These samples were conformed by pressing and fired in an eletrical furnace, at temperatures of 750, 800, 950 and 1000 degrees C. The ceramic bodies were evaluated with respect to their physical properties and mineralogical composition by X-ray diffraction and energy dispersive spectroscopy (EDS) mapping. The chromium immobilization was characterized by leaching tests according to Brazilian Regulations (NBR 10005). The results confirmed the immobilization of the chromium ion within the allowed limits of Brazilian Regulations, NBR 10004 (5mg/L), with the use of glass and vitrification/densification agents such as titanium and magnesium oxides.

Electrostatic painting residues as an alternative raw material for red clay industry

In this study, the viability of using electrostatic painting residues - paint sludge - as a raw material to the red clay industry was investigated. Red clay-based ceramic masses containing electrostatic paint residues were formulated during the study. The clays were obtained from the Rio do Rastro deposit, in Gravataí, and were of the standard formulation used in industry. Different ceramic mass formulations with additions of 0.5, 1.0, 2.5 and 5.0 wt.% electrostatic painting residue in addition to a formulation with no residue addition (standard formulation), were evaluated. The samples were uniaxially pressed in a double-effect press and were fired in an electric oven at 900, 950 and 1000°C. The firing at constant temperature lasted 8 h, and heating rate was 150 K h-1. After processing the samples were characterized in terms of their physical and mechanical properties. Environmental compatibility was also considered by the evaluation of gaseous emissions and leaching and solubilization tests according to the Brazilian standards NBR 10.005 and NBR 10.006, respectively. The results showed that it was possible to produce ceramic materials containing electrostatic painting residues within their formulations.

Utilization of Foundry Waste to Produce Ceramic Matrix Composites

The metallurgic industry, especially foundries, is a significant source of waste. For this reason, alternatives that involve reuse and recycling are necessary to minimize waste disposal in landfills and recover matter and energy. The feasibility of elaborating ceramic matrix composites with the incorporation of foundry waste was investigated in this study. Two types of residues were used to elaborate the composites. Green sand and grit blasting powder, in formulations with concentrations that ranged from 5.0 to 10.0% (m/m). The specimens were molded by uniaxial pressing, and a thermal treatment at 1000 °C was performed. The materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), particle size determination, linear retraction, water absorption, mechanical strength, leaching and solubilization. The results indicate that the incorporation of waste to the ceramic mass enables the processing of specimens with properties of industrial interest, such as mechanical strength and water absorption.

Avaliação de materiais e revestimentos para o controle de incrustações do mexilhão dourado Limnoperna fortunei (Dunker, 1857)

Foram realizados experimentos objetivando selecionar materiais e revestimentos com propriedades antiincrustantes para o controle do bivalve Limnoperna fortunei no sul do Brasil, em duas localidades: no canal principal do rio Jacui, Porto Alegre, RS, e no reservatorio da UHE Ibitinga, medio rio Tiete, SP. Os materiais testados foram: aco galvanizado, aco carbono, aco cobreado e cerâmica. Os revestimentos utilizados foram tintas: basica sem oxidos; basica com oxidos em concentracao de 5% como: ZnO nanometrico, particulas de ZnO convencional, Cu2O nanometrico, particulas de Cu2O convencional; e as tintas comerciais R e antibacterias. Corpos de prova com e sem revestimento (seis replicas de cada), foram submersos na coluna d’agua dos dois locais selecionados para os experimentos, entre outubro de 2006 e fevereiro de 2007. Quanto aos materiais metalicos, o cobre metalico, o aco galvanizado e aco carbono revestido com tinta comercial R e tinta antibacterias se demonstraram promissores no controle de incrustacoes do mexilhao dourado. Quanto ao material cerâmico, o revestimento de tinta base com ZnO comercial apresentou os melhores resultados. Nos materiais com e sem revestimentos, com elevadas densidades do bivalve, foi verificado que existe uma relacao com a alta incidencia de biofilmes, corrosao do material metalico e deterioracao do revestimento.

Seleção de materiais e revestimentos para o controle de incrustações do mexilhão dourado na Usina Hidrelétrica de Ibitinga (SP, Brasil)

Experiments were carried out aiming to select materials and coatings with antifouling properties against the exotic bivalve Limnoperna fortunei at power plants. Different kinds of materials were used as sample: carbon steel, metallic copper, stainless steel, galvanized steel and acrylic. Tests were also performed with several kinds of oxide based coatings at different concentrations on carbon steel samples. Copper oxide, zinc oxide and a combination of them were used. The samples were immersed in water column along a year, from October/2007 to September/2008, at Ibitinga Hydroelectric Power Plant Reservoir in Sao Paulo State, Brazil. The following materials and coatings showed the lower densities of golden mussel fouling: carbon steel coated with epoxy-polyamine resin based ink with addition of conventional zinc oxide 5%, carbon steel coated with epoxy-polyamine resin based ink with addition of conventional copper oxide 10% and carbon steel coated with epoxy-polyamine resin based ink with addition of nanometric zinc oxide 10%. These materials are recommended for use in golden mussel fouling control, after complementary studies about solubility, lixiviation and ecotoxicity, issues that will be considered in the new stage of the research.