Avaliação de uma proposta de reciclagem de veículos em fim de vida no Paraná baseado no modelo alemão

O crescente volume de veículos em fim de vida (VFV) no mundo nas últimas décadas despertou a preocupação com a gestão ambientalmente correta desses resíduos. Desde a década de 90 na Comunidade Europeia (CE), EUA e Japão a preocupação com a recuperação dos materiais dos VFV começou a fazer parte da rotina. A Alemanha desempenhou desde o início um papel impulsionador para o mundo neste tema. No Brasil, no entanto, apesar do aumento de veículos que deixam de circular no país, o tema da reciclagem ainda não ocupou o devido destaque nas discussões entre governo, empresários e sociedade para estabelecer política e legislação específica. Sendo assim, o principal objetivo deste estudo foi buscar uma comparação entre a gestão de VFV no Paraná (PR) e em Baden-Württemberg (BW) na Alemanha referente ao período que antecede junho de 2012, data da defesa da dissertação. A partir do levantamento dos dados foram feitas análises comparativas para identificar oportunidades e limitações da proposta de reciclagem de veículos no PR.

Extraction of rare earth elements via electric field assisted mining applying deep eutectic solvents

This study was partly financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil ( CAPES ) - Finance Code 001 Publisher Copyright: © 2022 Elsevier B.V.Rare earth elements play an important role in our society, as they are used in green energy technologies. However, they are considered critical raw materials. For this reason, there is a concern for obtaining alternative and complementary sources for conventional mining. In light of this view, electric field assisted mining arises as a technique to extract species from soils using green electrolytes to help in the extraction of metals. The aim of this paper was to evaluate the effect of different types of biodegradable electrolytes, including the use of deep eutectic solvents, in the electromining process. Six experiments were conducted applying an electric field of 1.0 V cm−1, and all electrolytes were used at a concentration of 0.1 mol L−1. The results showed that different electrolytes achieved different selectivities. The maximum efficiency using acetic acid resulted in 69.1% of Ce4+, citric acid removed 62.3% of La3+, and oxalic acid extracted 21.5% of La3+. The electromining efficiencies using deep eutectic solvents presented minor results. Therefore, considering the biodegradability and selectivity of the organic acids used, electromining showed to be a promising eco-friendly alternative for preferential extraction of metal species from soils.proofpublishe

Optimization of Electric Field Assisted Mining Process Applied to Rare Earths in Soils

The extraction of rare earths has been studied worldwide, however some of these processes have a high cost and can cause negative environmental impacts. In order to mine these species from the soil, Electric Field Assisted Mining arises as an alternative to conventional mining processes. Therefore, the experimental parameters can be improved to obtain better results in the extraction of these species. The aim of this paper is to propose the optimization of the Electric Field Assisted Mining process of yttrium, to obtain the optimal experimental configuration to be applied in real soils. An optimization problem was defined to obtain the maximum extraction mass of yttrium ion (Y3+), considering the limitation for the quantity of electric current density. A hybrid optimization technique was used, based on the sequential application of genetic algorithms and non-linear programming. Different optimal process configurations were obtained, considering distinct limits for the electric current density. The best experimental configuration resulted in 0.5386 V cm−1 electric field strength and 0.10 mol L−1 electrolyte concentration. This condition was reproduced in real soil, which obtained a Y3+ electromining efficiency of 41.48%. The results showed that this technique is promising for the extraction of rare earth in real soils

A FORMAÇÃO DA CAMADA PROTETORA DE FeCO3 E O CONTROLE DA CORROSÃO POR CO2 EM CONDIÇOES DE FLUXO TURBULENTO

The formation of a protective layer of iron carbonate (FeCO3) can reduce the rates of corrosion and prolong the useful life of carbon steel. However, turbulent flow conditions in this layer can easily be damaged and thus compromise the protection of the steel. In this work, will be presented a methodology based on the chemical aspects of the mechanism of formation of iron carbonate layer in a Thin Channel Flow Cell (TCFC). Electrochemical techniques were used to measure the corrosion rate and corrosion potential on the surface of steel API X65 exposed to aqueous solution of 1 wt.% NaCl purged with CO2 at 2 atm, pH 6.6 and 80°C in turbulent flow conditions. The surfaces and cross sections of the samples were characterized by means of Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDS) analysis. The results confirm the nucleation and growth of iron carbonate layer: the extension of supersaturation of the solution and the corrosion rate have decreased, and the corrosion potential has increased. The surface analysis showed dense and uniform FeCO3 layer with c.a. 20 µm thick after 120 hours in turbulent flow conditions

Electroremediation of deactivated catalysts from fluidised catalytic cracking for vanadium removal - the effect of a dual cathode chamber reactor

<div><p>Abstract The aim of this study was to evaluate the quantity of vanadium removed through electrokinetic remediation applied to catalyst waste used in a fluid catalytic cracking process. In excess, vanadium affects process efficiency by reducing the catalyst’s activity, causing deactivation and reducing its useful life in petroleum cracking during refining. The electrochemical reactor used was composed of an extra cathode chamber coupled with an ion-selective cation exchange membrane, Nafion ®. The function of the cathode chamber was to increase the overpotential for a hydrogen reduction reaction (HRR) and the electric field to favour metal ion removal. Sodium citrate was used for electrolyte remediation (complexing vanadium) at 0.5 mol/L with an 11.0 V (ε =0.5 V/cm) potential applied. The treatment efficiency was analysed based on the vanadium ion concentration in the electrolyte collected. The results show that electrokinetic remediation using the dual cathode chamber yielded more metal removal and lower energy consumption.</p></div