The aim of this work was to evaluate mass loss in each stage of the recycling process for metal recovery from PCBs of controllers and temperature indicators of cold chambers. The stages of process consists of grinding, particle size classification, magnetic and electrostatic separation. It was analyzed 13 kg of PCBs. These PCBs were crushed and ground. The ground material were subjected to magnetic and electrostatic separator. The losses in the comminution stages were 12.69 % and are lower than those found in other related works that used mixtures of different types of PCBs, whereas in this work only one model plates were analyzed. 27.2 % absolute mass loss we reached out after particle size separation with Tyler Series with 1 mm sieve presents the higher mass losses in the whole process and this fraction was not processed as it results in PCBs powder dust that interferes negatively in the electrostatic separation. Comparing the losses in the stages of shredding of PCBs employed in temperature controllers with other studies involving PCBs from the automotive industry and from computers and cell phones, is remarkable that this type of board presents significantly greater potential to be processed for recovery of its materials.

Abstract Currently, the printed circuit boards (PCB) of waste electrical and electronic equipment (WEEE) are attracting interest among researchers for environmental concern reasons and mainly for their content of precious metals such as gold. Thus, this study aims to characterize different types of PCBs from mobile phones in relation to the amount of gold contained, to evaluate alternative leaching agents for the gold (ammonium and sodium thiosulfate) and compare these to commercial stripping (cyanide-based) and then the recovery of gold by the electrometallurgical route. First, the amount of gold was determined. Then, alternative leaching agents were tested under different concentrations and time. A cyanide-based solution was also tested to compare the results. The results showed that the content of gold varied from 142 to 700 g/ton. The cyanide-based solution was able to extract 88% of the gold, while sodium and ammonium thiosulfate extracted 70 and 75% of the gold, respectively. The electrowinning tests showed a 94% recovery of the gold present in thiosulfate solutions.

Abstract Interest in recycling for the recovery of valuable substances, such as precious metals from electric and electronic waste has been increasing year after year due to the large amount present in such waste compared to primary sources. There is environmental concern, since the amount of this kind of waste is increasing due to rapid technological advances. This study aimed to test the different operating conditions of an electrostatic separator for the concentration of copper from printer circuit boards (PCB). The PCBs were milled in knife mills and separated according to the difference of granule sizes into two fractions: A (<0.5 mm); B (0.5<B<1 mm), followed by scaling. Then, the samples were subjected to a magnetic separator for removing the magnetic materials to obtain a concentrate with a higher content of copper. After the magnetic separator, an electrostatic separator was used, where different conditions were employed for each sample: roller rotation (100 and 175 rpm) and tension (20 and 35 kV). Iron concentrations were observed after the magnetic separator, between 12 and 14.1% for the A fractions and 10.3-11.4% for the B fractions. After the electrostatic separator, the results for the A samples showed that the concentration of copper varies between 17.5 and 51.1%, with the highest concentration obtained through the use of 100 rpm (roller rotation) and 35 kV (voltage). For the B samples, the variation was between 6.4 and 40.5 %. For both particle sizes, the best applied condition was a voltage of 35 kV and a roller rotation of 100 rpm.

The disposal of CRT monitors increases each year, generating millions of tons of waste containing various types of materials. The glass present in CRT tubes displayed about 20%-25% of lead oxide. If improperly disposed of, this glass can be leached directly in nature or may cause environmental contamination, especially with lead. Because of this leaching possibility, this waste is classified as Class I solid waste, according to the NBR 10004. Thermal processing of these glass tubes was seen as an alternative to remove lead from the glass matrix. Parameters such as reaction time, percentage of reducing agent, the reaction temperature, and atmospheric environment of the system were analyzed in this work. It was concluded that it is possible to remove the lead from the glass matrix by thermal processing. The removal of 92% of the lead from the glass was obtained at 800°C, a vacuum of 1.3 kPa, with 5% carbon as a reducing agent, and 18 hours of thermal processing.

Nos dias atuais, há uma infinidade de modelos, tamanhos e configurações de equipamentos eletro-eletrônicos disponíveis para o consumo. Visando a realizar a reciclagem e o reaproveitamento dos metais preciosos encontrados nas placas de circuito impresso (PCI) dos celulares, esse trabalho tem o objetivo de caracterizar o ouro presente nas PCI dos aparelhos celulares e desenvolver uma rota de reciclagem para o ouro e a prata, utilizando reagentes alternativos ao cianeto, como o tiossulfato de sódio e tiossulfato de amônio. Esses reagentes agridem, numa menor intensidade, o meio ambiente e a saúde do trabalhador. Primeiramente realizou-se uma caracterização com água-régia. Os resultados mostraram 86.26g Au/tonPCI e 123.85g Ag/tonPCI. Na segunda caracterização, foi utilizado o reagente comercial a base de cianeto e o resultado foi de 112.02g Au/tonPCI e 26.13gAg/tonPCI. Para a lixiviação com tiossulfato de sódio, chegou-se ao resultado de 9.02g Au/tonPCI, na lixiviação do ouro, e de 33.88g Ag/tonPCI, na lixiviação da prata, comparando com os resultados da caracterização usando reagentes a base de cianeto.

Nowadays there is a wide variety of models, sizes and configurations of mobile phones available for consumption. After the life cycle of this equipment, the recycling and reuse of the precious metals found in the printed circuit boards (PCB) of the mobile phones are principal objectives. Thus, the objective of this work was to characterize the gold and silver present in a PCB and develop a recycling route using alternative reagents for cyanide, such as sodium and ammonium thiosulfate. These reagents are less harmful to the environment and worker health. The first characterization of gold and silver was performed with aqua regia. The results show 86.26g Au/ton of PCBs and 123.85g Ag/ton of PCBs. The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a cyanide-based reagent.

A quantidade de resíduos sólidos gerados por todos os segmentos da sociedade tem aumentado nas últimas décadas. Anualmente, no Brasil, são gerados 96 mil toneladas de sucata eletrônica proveniente de computadores. O descarte incorreto desses resíduos gera danos ao meio ambiente, bem como perda de materiais que poderiam ser reaproveitados e/ou reciclados, diminuindo, assim a extração de matérias-primas para a produção de novos materiais. As placas de circuito impresso (PCI) correspondem a, aproximadamente, 30% da sucata eletrônica gerada. Cabe ressaltar que realizar a reciclagem dessa sucata é um processo complexo, porém de extrema importância para a recuperação de metais de grande valor econômico. Os processos industriais, para a recuperação de metais provenientes de PCI, são baseados, em pirometalurgia e hidrometalugia. Em ambos os processos, é possível fazer um pré-tratamento, que consiste no uso de processos mecânicos. Desta forma, nesse trabalho, foi realizada a concentração da fração metálica das PCI através do uso de um concentrador Mozley. Os resultados mostram que é possível obter quantidades significativas de metais como cobre (concentração de 85%), estanho (95%) e prata (98%) nas frações de interesse.

The amount of solid waste generated by all segments of society has increased in past decades. Annually, in Brazil, 96,000 tonnes of electronic scrap are generated from computers. The incorrect disposal of this waste creates environmental damage, generating loss of materials that could be reused and / or recycled, reducing the extraction of recyclable materials to produce new materials. The printed circuit boards (PCB) represent approximately 30% of the electronic waste generated and its recycling is a complex process, but very important for the recovery of metals of high economic value. Industrial processes for the recovery of metals from PCB are based on pyrometallurgy and hydrometallurgy. In both cases, it is possible to carry out a pretreatment that involves the use of mechanical processes. Therefore, for this paper, the concentration of the metallic fraction of PCB through the use of a Mozley concentrator was enabled. The results show that it is possible to obtain significant quantities of metals such as copper (concentration 85%), tin (95%), and silver (98%) in the fractions of interest.

No processo de têmpera por indução, o material é aquecido por um campo magnético gerado por uma corrente alternada de alta frequência, que passa através de uma bobina. Para melhorar a eficiência do processo, são utilizados, junto à bobina, orientadores de fluxo magnético, que são materiais magnéticos moles. Esses orientadores de fluxo são constituídos de componentes ferromagnéticos e um ligante dielétrico. Geralmente é necessário realizar um ajuste dimensional desses concentradores, através de usinagem, gerando perda de matéria-prima e produção de resíduo. Nesse trabalho, foi realizada a elaboração de um compósito de matriz polimérica a partir do resíduo oriundo do processo de ajuste dimensional. Para elaboração desse compósito, o resíduo foi cominuído e misturado com dois tipos diferentes de resinas fenólicas na concentração de 3%. Os compósitos magnéticos obtidos foram caracterizados quanto à morfologia, propriedades mecânicas, magnéticas, elétricas e caracterização ambiental. Os resultados mostraram que os compósitos apresentaram redução das propriedades magnéticas e mecânicas comparativamente ao material original. Mesmo assim o material apresenta potencial para uso como concentrador de fluxo, pois foi observada a redução das perdas magnéticas.

In the induction heating treatment process, the material is heated by a magnetic field generated by a high frequency alternating current that passes through an inductor. To improve the efficiency of the process, a flux concentrator, which is constituted by soft magnetic materials, is used. This flux concentrator consists of ferromagnetic components and a dielectric binder. In some industrial processes, the dimensional adjustment of this tool can cause loss of raw material and produce waste. The aim of this work was the elaboration and characterization of a magnetic composite of polymeric matrix from the waste generated by the dimensional adjustment. To prepare the magnetic composite, the waste was comminuted and mixed with two different types of phenolic resin at a concentration of 3%wt. The magnetic composites obtained were characterized according to morphology, mechanical, magnetic and electrical properties and environmental characterization. The results showed that the composites presented a reduction of magnetic and mechanical properties compared to the original material. However, reduction of magnetic losses was observed for the composite obtained, highlighting the potential of this composite for use as a magnetic flux concentrator.

O crescimento constante na geração de resíduos sólidos em todo o mundo tem estimulado estudos para os mais variados tipos de resíduos. Nesse trabalho, foram estudadas as Placas de Circuito Impresso (PCI), que fazem parte das sucatas eletrônicas e que são encontradas nos equipamentos eletroeletrônicos. As PCI são compostas de polímeros, cerâmicos e metais, o que dificulta o seu processamento. Na primeira etapa desse trabalho, foi utilizado processamento mecânico, como moagem, separação granulométrica, magnética e eletrostática para se obterem uma fração concentrada em metais (principalmente Cu) e uma outra fração contendo polímeros e cerâmicos. Na segunda etapa, a fração concentrada em metais foi dissolvida e enviada para uma eletroobtenção a fim de recuperar o cobre. O teor de cobre alcançou mais de 50% em peso nas frações condutoras e significativos teores de chumbo e estanho. No segundo estágio, as frações concentradas em metais foram dissolvidas com ácidos e tratadas em um processo eletroquímico, a fim de se recuperarem os metais separadamente, especialmente o cobre. Os resultados demonstram a viabilidade técnica para se recuperarem cobre usando processamento mecânico seguido de uma técnica eletrometalúrgica. O conteúdo de cobre, em solução decaiu rapidamente em todos os experimentos e o cobre obtido por eletroobtenção apresentou teores acima de 97% na maioria dos testes.

The constant growth in the generation of solid residues in the world stimulates studies for most types of residual recycling. In this work Printed Circuit Boards, that are part of electronic scraps and are found in electro-electronic equipment, were studied. Printed Circuit Boards are composed of polymers, ceramics and metals, making their processing difficult. During the first stage of this work, mechanical processes, such as comminution, sizing, magnetic and electrostatic separation were used to obtain two concentrated fractions”one with metals (mainly Cu) and the other with polymers and ceramics. During the second stage, the metal-concentrated fraction was dissolved with acids and treated in an electrochemical process to separate the metals. The results were that there was more than a 50% copper content in most of the conductive fractions and also, a significant content of Pb and Sn. This demonstrated the technical feasibility of copper recovery using mechanical processing followed by an electrometallurgical technique. The copper content in solution decayed quickly in all the experiments and the copper obtained by electrowinning was above 97% in most of the tests.