954 resultados para Ceramic raw materials


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This project was born with the aim of developing an environmentally and financially sustainable process to dispose of end-life tires. In this perspective was devised an innovative static bed batch pilot reactor where pyrolysis can be carried out on the whole tires in order to recover energy and materials and simultaneously save the energy costs of their shredding. The innovative plant is also able to guarantee a high safety of the process thanks to the presence of a hydraulic guard. The pilot plant was used to pyrolyze new and end-life tires at temperatures from 400 to 600°C with step of 50°C in presence of steam. The main objective of this research was to evaluate the influence of the maximum process temperature on yields and chemical-physics properties of pyrolysis products. In addition, in view of a scale-up of the plant in continuous mode, the influence of the nature of several different tires as well as the effects of the aging on the final products were studied. The same pilot plant was also used to carry out pyrolysis on polymeric matrix composites in order to obtain chemical feedstocks from the resin degradation together with the recovery of the reinforcement in the form of fibers. Carbon fibers reinforced composites ad fiberglass was treated in the 450-600°C range and the products was fully characterized. A second oxidative step was performed on the pyrolysis solid residue in order to obtain the fibers in a suitable condition for a subsequent re-impregnation in order to close the composite Life Cycle in a cradle-to-cradle approach. These investigations have demonstrated that steel wires, char, carbon and glass fibers recovered in the prototypal plant as solid residues can be a viable alternative to pristine materials, making use of them to obtain new products with a commercial added value.

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This article attempts to analyse and investigate the implications of the approach to the applicability of Article XX GATT adopted in the recent China – Raw Materials. Using the decision on the non-availability of Article XX defences for violations of China’s WTO-plus commitments on export duties as a backdrop, it scrutinizes the more general, ‘systemic’ approach to the applicability of Article XX exceptions developed by theWTO dispute settlement bodies, and sheds light on the implications of such approach with respect to the relationship between GATT 1994 andWTO obligations arising from different instruments of theWTOAgreement, such as new members’ accession protocols. It also suggests that an exception to this general approach could be envisaged when the fundamental environmental goals protected under Article XX b) and g) are at stake.

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Biochar can provide multiple benefits in the ecosystem. However, the presence of phytotoxic compounds in some biochars is an important concern that needs to be addressed and that depends on the raw material and the pyrolysis conditions used in biochar production. For example, sewage sludge biochars can have elevated heavy metal con- tents as they were present in the feedstock and were enriched during pyrolysis. Also during carbonization, some phytotoxic compounds such as polycyclic aromatic hydrocarbons (PAHs), polyphenols or volatile organic com- pounds (VOCs) could be formed representing a risk of contamination to soils and crops. In this work we report the results from seed germination and plant development for three biochars prepared from wood, paper sludge plus wheat husks and sewage sludge. Five higher plant species (cress, lentils, cucumber, tomato and lettuce) were studied. Biochar from wood shows seed inhibition in several species and the paper sludge biochar on lettuce. For the rest, the effect on seed germination was positive. No inhibition of root growth was detected, but in some cases leaves and stems growth were inhibited. Our results are significant in terms of advancing or current understanding on the impacts of biochar on vegetative growth and linking those effects to biochar properties.

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In light of the growing international competition among states and globally operating companies for limited natural resources, export restrictions on raw materials have become a popular means for governments to strive for various goals, including industrial development, natural resource conservation and environmental protection. For instance, China as a major supplier of many raw materials has been using its powerful position to both economic and political ends. The European Union (EU), alongside economic heavyweights such as the US, Japan and Mexico, launched two high-profile cases against such export restrictions by China at the WTO in 2009 and 2012. Against this background, this paper analyses the EU’s motivations in the initiation of trade disputes on export restrictions at WTO, particularly focusing on the two cases with China. It argues that the EU's WTO complaints against export restrictions on raw materials are to a large extent motivated by its economic and systemic interests rather than political interests. The EU is more likely to launch a WTO complaint, the stronger the potential and actual impact on its economy, the more ambiguous the WTO rules and the stronger the internal or external lobbying by member states or companies. This argumentation is based on the analysis of pertinent factors such as the economic impact, the ambiguity of WTO law on export restrictions and the pressure by individual member states on the EU as well as the role of joint complaints at the WTO and political considerations influencing the EU’s decision-making process.