A method of suppressing chaotic oscillations in a tubular reactor with mass recycle is discussed. The method involves intervention in the temperature of the input flow by the recirculation flow and the temperature set from the exterior. The most advantageous solution was proved to be heat coupling elimination and maintenance of the reactor input temperature on the set level. Moreover, the reactor modelwas identified on the basis of a chaotic solution, as it provides the biggest entropy of information.
A356 is one of the widely used aluminium casting alloy that has been used in both sand and die casting processes. Large amounts of scrap
metal can be generated from the runner systems and feeders. In addition, chips are generated in the machined parts. The surface area with
regard to weight of chips is so high that it makes these scraps difficult to melt. Although there are several techniques evolved to remedy
this problem, yet the problem lies in the quality of the recycled raw material. Since recycling of these scrap is quite important due to the
advantages like energy saving and cost reduction in the final product, in this work, the recycling efficiency and casting quality were
investigated. Three types of charges were prepared for casting: %100 primary ingot, %100 scrap aluminium and fifty-fifty scrap
aluminium and primary ingot mixture were used. Melt quality was determined by calculating bifilm index by using reduced pressure test.
Tensile test samples were produced by casting both from sand and die moulds. Relationship between bifilm index and tensile strength were
determined as an indication of correlation of melt quality. It was found that untreated chips decrease the casting quality significantly.
Therefore, prior to charging the chips into the furnace for melting, a series of cleaning processes has to be used in order to achieve good
quality products.
Industrial steelmaking (EAF) flue dust was characterized in terms of chemical and phase compositions, leaching behaviour in 20% sulphuric acid solution as well as leaching thermal effect. Waste product contained about 43% Zn, 27% Fe, 19% O, about 3% Pb and Mn and lesser amounts of other elements (Ca, Si, Mo, etc.). It consisted mainly of oxide-type compounds of iron and zinc. Dissolution of metals (Zn, Fe, Mn) from the dust was determined in a dependence of solid to liquid ratio (50-200 g/L), temperature (20-80oC) and leaching time (up to 120 min). The best result of 60% zinc recovery was obtained for 50 g dust/L and a temperature of 80oC. Leaching of the material was an exothermic process with a reaction heat of about –318 kJ/kg. Precipitation purification of the solution was realized using various ratios of H2O2 to NH3aq. A product of this stage was hydrated iron(III) oxide. Final solution was used for zinc electrowinning. Despite that pure zinc was obtained the highest cathodic current efficiency was only 40%.
The presented article describes the method for determining one of the trace elements occurring in coalbismuth. The subjects of the analysis were coal type 34, 35 and their fly ashes derived from Jastrzębska Spółka Węglowa. The main reason for the research was the extensive use of bismuth in many industry sectors. Additionally, bismuth is on the list of deficit elements, therefore the possibility of obtaining an alternative for its recycling source of it is needed, is required. The research was carried out using atomic absorption spectrometry with electrothermal atomization in a graphite cuvette. The samples were incinerated at 800°C and microwave mineralization in a high-pressure closed system was performed until the spectrometric analysis was achieved. In order to achieve mineralization, a mixture of HF and HNO3 acids was used to turn the samples into acidic solutions. The preparation of the samples was based on available literature data and own observations. In the experiment, the effects of the additive modifier was modified by changing the temperature in further steps: drying, incineration, cooling, atomization and burning were described. In addition, the palladium modifier was used in order to limit secondary reactions and enable the evaporation of matrix components. The measurement conditions which are presented in this article allow for a linear calibration curve to be established. However, this is not clear and the definitive method for determining the bismuth in coal is carried out through the use of ET-AAS.
Building a Strategic Battery Value Chain in Europe COM/2019/176 is a priority for EU policy. Europe’s current share of global cell production is only 3%, while Asia has already reached 85%. To ensure a competitive position and independence in the battery market, Europe must act quickly and comprehensively in the field of innovation, research and construction of the infrastructure needed for large-scale battery production. The recycling of used batteries can have a significant role in ensuring EU access to raw materials. In the coming years, a very rapid development of the battery and rechargable battery market is forecast throughout the EU. In the above context, the recycling of used batteries plays an important role not only because of their harmful content and environmental impact, or adverse impact on human health and life, but also the ability to recover many valuable secondary raw materials and combine them in the battery life cycle (Horizon 2010 Work Programme 2018–2020 (European Commission Decision C(2019) 4575 of 2 July 2019)). In Poland, more than 80% of used batteries are disposable batteries, which, together with municipal waste, end up in a landfill and pose a significant threat to the environment. This paper examines scenarios and directions for development of the battery recycling market in Poland based on the analysis of sources of financing, innovations as well as economic and legal changes across the EU and Poland concerning recycling of different types of batteries and rechargable batteries.
In this paper, the kinetics of the platinum(IV) chloride complex ions reduction reaction was studied. It was shown that the mechanism exhibits autocatalytic character. The presence of metallic platinum in the system significantly increases the reaction rate. The influence of the initial concentration of precursor, reductant, ionic strength, initial concentration of the chloride ions as well as the temperature on the process rate was investigated. The activation energy was determined and is equal to 93.57 kJ/mol. Moreover, the obtained metallic phase was analyzed, and it was observed that it has a micrometric size.
Production waste is one of the major sources of aluminium for recycling. Depending on the waste sources, it can be directly melted in furnaces, pre-cleaned and then melted, or due to the small size of the material (powder or dust) left without remelting. The latter form of waste includes chips formed during mechanical cutting (sawing) of aluminium and its alloys. In this study, this type of chips (with the dimensions not exceeding 1 mm) were melted. The obtained results of laboratory tests have indicated that even chips of such small sizes pressed into cylindrical compacts can be remelted. The high recovery yield (up to 94 %) and degree of metal coalescence (up to 100 %) were achieved via thermal removal of impurities under controlled conditions of a gas atmosphere (argon or/and air), followed with consolidation of chips at a pressure of minimum 170 MPa and melting at 750 oC with NaCl-KCl-Na3AlF6 salt flux.