RESUMO Os efluentes e resíduos industriais galvânicos são uma preocupação mundial, por terem em sua composição metais-traço altamente tóxicos, prejudiciais ao meio ambiente e à saúde humana. Neste artigo, é apresentado um panorama da indústria de semijoias folheadas de Juazeiro do Norte, Ceará, considerando-se os processos de produção e a concentração de metais-traço nos efluentes, bem como o resíduo sólido galvânico, gerados pelo setor. Dados primários de produção foram obtidos em 11 empresas por meio de questionário técnico. As concentrações de metais-traço foram obtidas por espectrofotometria de absorção atômica de chama. Os resultados demonstraram ineficiência no tratamento dos efluentes para cobre, níquel, cromo, chumbo e zinco. As concentrações médias de metais no resíduo sólido galvânico foram de 239 g Cu kg-1, 99 g Zn kg-1, 23,8 g Ni kg-1, 6,6 g Pb kg-1, 0,2 g Cr kg-1, 1,7 g Cd kg-1, 1,0 g Mn kg-1 e 8,2 g Fe kg-1. Os resultados evidenciaram a necessidade da adoção de medidas para o controle de qualidade dos processos de tratamento dos efluentes, com vistas à sustentabilidade do setor.

ABSTRACT Galvanic industrial effluents and wastes are a worldwide concern, as they contain highly toxic trace metals that are harmful to the environment and human health. This article presents an overview of the clad semi jewelry industry in Juazeiro do Norte, state of Ceará, Brazil, considering the production processes and the concentration of trace metals in the effluents and galvanic sludge waste generated by the sector. Primary production data were obtained from 11 companies by a technical questionnaire. Trace metal concentrations were obtained by flame atomic absorption spectrophotometry. The results showed inefficiency in the treatment of effluents for copper, nickel, chrome, lead, and zinc. The average metal concentrations in the galvanic sludge waste were 239 g Cu kg-1, 99 g Zn kg-1, 23.8 g Ni kg-1, 6.6 g Pb kg-1, 0.2 g Cr kg-1, 1.7 g Cd kg-1, 1.0 g Mn kg-1, and 8.2 g Fe kg-1. The results evidenced the need for adopting measures concerning quality control of the effluent treatment processes aiming at the sustainability of the sector.

ABSTRACT Red ceramics are part of one of the sectors of ceramic materials that make up the formation of the civil construction complex. In Cariri region and in the rest of Brazil, this segment uses clay as the main source of raw material, which favors the appearance of micro, small and medium enterprises that produce most of the products manufactured by the red ceramic sector. The objective of this work was the mineralogical and technological characterization of a clay sample from one of the potteries in Cariri region, intended for the manufacture of products to be used in civil construction such as tiles and bricks. For that, the techniques of X-ray fluorescence and X-ray diffraction were used, in addition to determining the physical-mechanical properties of the specimens by 4 ton-force uniaxial pressing followed by firing at 800, 900 and 1000ºC. The results showed that the sample is composed of quartz, kaolinite, smectite and muscovite and that it has granulometry mostly in fine fractions; after firing the clay shows reddish color and the Atterberg limits are within the range indicated for use on red ceramics. The clay under study has technological properties suitable for manufacture and the specimens burned at 800°C do not meet the values indicated by the literature. The studied clay proved to be suitable for application in tiles and perforated bricks.

RESUMO A eletrodeposição de cobre em substratos ferrosos e não-ferrosos a partir de soluções contendo cianeto é uma das formas mais utilizadas industrialmente. Os depósitos obtidos por esse processo apresentam alta qualidade com baixo custo operacional, equipamentos pouco sofisticados e pré-tratamento simples no substrato. No entanto, novos eletrólitos isentos de íons cianetos têm surgido para substituir as soluções cianídricas que são tóxicas e com grande potencial de causar danos ambientais e a saúde. O objetivo deste trabalho foi a obtenção do cobre eletrodepositado (Cu eletrolítico) por corrente contínua a partir de um banho de sulfato de amônio e citrato de sódio; e, avaliar as características deste com as do cobre eletrolítico comercial (Cu comercial), bem como analisar duas metodologias de preparação da superfície metálica para análise por microscopia. As técnicas de caracterização utilizadas foram Difração de Raios-X (DRX), Microscopia Eletrônica de Varredura (MEV), Microscopia Óptica (MO) e nanodureza, as superfícies das amostras foram preparadas por polimento convencional e eletrolítico. Observou-se que as amostras polidas eletroliticamente mostraram-se bastante brilhantes e apresentaram os contornos dos grãos com maior nitidez, os mesmos resultados não foram evidenciados pelo polimento convencional. O cobre obtido pelo banho isento de cianeto apresentou menores tamanhos de grãos e uma maior dureza dentro destes, quando comparado ao Cu comercial. O difratograma apresentou para o Cu eletrolítico picos de alta intensidade nos planos (200) e (111) mostrando uma maior orientação cristalográfica preferencial nas direções desses planos. Por fim, o MEV mostrou uma segregação de uma fase no Cu eletrolítico, causada pela eletrodeposição e também as formas dos grãos poligonais com microcavidades globulares do Cu comercial.

ABSTRACT The electrodeposition of copper on ferrous and non-ferrous substrates from solutions containing cyanide is one of the most used industrial forms. The deposits obtained by this process are of high quality with low operating cost, unsophisticated equipment and simple pre-treatment in the substrate. However, new cyanide-free electrolytes have emerged to replace cyanide solutions that are toxic and have a great potential to cause environmental and health damage. The objective of this work was to obtain electrodeposited copper (electrolytic Cu) by direct current from an ammonium sulfate and sodium citrate bath; and, evaluate its characteristics with those of commercial electrolytic copper (commercial Cu), as well as analyze two methodologies for preparing the metallic surface for analysis by microscopy. The characterization techniques used were X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Optical Microscopy (MO) and nano hardness, the sample surfaces were prepared by conventional and electrolytic polishing. It was observed that the electrolytically polished samples were very bright and showed the grain contours with greater clarity, the same results were not evidenced by conventional polishing. The copper obtained by the cyanide-free bath showed smaller grain sizes and a greater hardness inside them, when compared to commercial Cu. The diffractogram showed high intensity peaks for the electrolytic Cu in the planes (200) and (111) showing a greater preferential crystallographic orientation in the directions of these planes. Finally, the SEM showed a segregation of a phase in the electrolytic Cu, caused by the electrodeposition and also the shapes of the polygonal grains with globular microcavities of the commercial Cu.