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Number of results: 31
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Abstract

The presented in the paper investigations were aimed at the determination of the reclaimed material (obtained in the dry mechanical reclamation process) addition influence on properties of moulding sands with hydrated sodium silicate modified by colloidal suspension of zinc oxide nanoparticles in propanol. Nanoparticles originated from the thermal decomposition of alkaline zinc carbonate, were used. The results of the reclamation of the spent moulding sand with hydrated sodium silicate performed in the AT-2 testing reclaimer are presented in the paper. Both, spent sands from the Floster S technology and from the technology with the modified water-glass were subjected to the reclamation processes. The following determinations of the reclaimed material were performed: pH reaction, acid demand, ignition loss and Na2O content. The obtained reclaim was used as a matrix component of moulding sands with water-glass in the Floster S technology, in which it constituted 60% and 50% of the sand matrix. The strength properties of the prepared moulding sands were determined (bending strength Rg u , tensile strength Rm u ) after samples storing times: 1h, 2h, 4h and 24 hours.
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Abstract

In this article, there were presented results of research on influence of reclamation process on the ecological quality of reclaim sand with furan resin used in nonferrous foundry. The quality of reclaimed sand is mainly define by two group of chemical substances from elution of reclaimed sand: Dissolves Organic Carbon (DOC) and Total Dissolves Solids (TDS). Reclaimed sand used in test was prepared in experimental thermal reclaimer and mechanical vibration reclaimer REGMAS installed in Faculty of Foundry Engineering at University of Science and Technology in Krakow. The reference point is molding sand shaking out and crumble in jaw crusher. Test of elution was made in acreditation laboratory in Center For Research and Environmental Control in Katowice up to the standard with Dissolves Organic Carbon (DOC) - PN-EN 1484:1999; Total Dissolves Solids (TDS) - PN-EN 15216:2010. The standard for elution test is PN-EN 12457- 4:2006. Except that we were made loss of ignition test, to check how many resin was rest on sand grains.
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Abstract

The thermal reclamation process as a utilisation method of spent moulding and core sands is more costly than other reclamation methods, but in the majority of cases it simultaneously provides the best cleaning of mineral matrices from organic binders. Thus, the application of the thermal analysis methods (TG-DSC), by determining the temperature range within which a degradation followed by a destruction of bounded organic binders in moulding sands, can contribute to the optimisation of the thermal reclamation process and to the limiting its realisation costs. The thermal analysis results of furan resin, one of the most often applied binder in foundry practice, are presented in the hereby paper. The influence of the heating rate of the sample - placed in the thermal analyser - on its degradation and destruction process under oxygen-free (argon) and oxygen (air) conditions, were compared. The recorded TG and DSC curves were used for analysing these processes as the temperature as well as the time function. The obtained results were analysed with regard to determining the required temperature of the thermal reclamation of the investigated organic binder. The usefulness of the developed methodology was found out, however under conditions of meeting several essential requirements concerning the repeatability of performed analyses.
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Abstract

One of the biggest problems for sand casting foundries must be the waste produced from disposable molds. Stricter environmental regulations make it harder to dispose of waste sand, so a truly competitive foundry does no longer only make great products, but also concentrates on a sustainable casting process. While methods for repurposing waste foundry sand are still limited, the internal circulation of such sands proves significant possibilities. This paper will focus on thermal reclamation of foundry sands in a special rotating drum furnace in a central facility to serve several foundries. Thermal reclamation is a process for handling foundry sands in elevated temperatures to combust unwanted substances from reusable base sand. The introduction focuses on background of the Finnish foundry business, the most common sand systems in Finland and their reclaim properties. The experimental part features presentation of the new reclamation plant process and the conducted test runs. The samples collected from each test run have been laboratory tested to assure proper sand quality. The results of this work showed that the reclamation of alkaline phenolic no-bake sands was excellent. Reclamation of green sands did not provide satisfactory results as expected and the reclamation of furan no-bake sands provided mixed results, as the raw material was imperfect to begin with. The most important result of this work is still the successful initiation of a centralized thermal reclamation plant, with the ability to reclaim sands of several foundries. With this all of industrial symbiosis, circular economy and sustainability advanced in Finland, and the future development of this plant provides even further opportunities and a possibility to spread the ideas on a global scale.
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Abstract

The paper presents results of floristic investigation conducted within the territory of post-industrial spoil heaps connected with zinc and lead products manufacturing. The flora of specific technogenic habitats was analyzed with regard to geographical-historical groups and syntaxonomic classification. For each species, the following characteristics were determined: a life form according to the classification of Raunkiaer, means of seed spreading and types of mycorrhiza for each species based on the literature. On the two heaps, a total of 257 species of vascular plants belonging to 59 families were found. Only 92 species occurred on both sites, which is 36% of all plants recorded. The most numerous families are: Asteraceae (45 species) and Poaceae (28 species). Apophytes dominate in the flora of spoil heaps (70.9%). Hemicryptophytes are the most numerous group and therophytes are also abundant. Ruderal (belonging to Artemisietea vulgaris and Stelarietea mediae) and meadow species (belonging to Molino-Arrhenatheretea) dominate on both post-industrial dumps. Xerothermal species (belonging to Festuco-Brometea) are also fairly numerous (6.7%). Their presence is related to the specific habitat conditions. The anemochoric species dominate in the flora of dumps. The high proportion of mycorrhizal plants was recorded. Finally, reclamation interventions which were carried out on the H2 spoil heap are discussed.
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Abstract

The paper summarizes research realized by the author in laboratory and industrial conditions (foundries of cast steel and cast iron, castings up to 50 tons) on the effects of the chemically hardened molding sands regeneration using hard/soft rubbing in the dry reclamation. A reference was simultaneously made to advisability of application of the thermal regeneration in conditions, where chromite amount in the circulating (reclaimed) molding sand goes as high as above ten percent. An advisability of connecting standard and specialized methods of examination of the reclaimed sands and molding sands made using it was pointed out. A way of application of studies with the Hot Distortion PlusĀ® method modified by the author for validation of modeling of the thermo-dynamic phenomena in the mold was shown.
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