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Abstract

The aim of the study was to determine the influence of the amount of a commonly used binder in foundry work, furfuryl resin – on the course of the thermal regeneration of used moulding sand. The thermal regeneration procedure was carried out at a temperature of 525°C, the required temperature determined according to a specific procedure, and a lower and less effective temperature of 400°C. On the basis of the ignition losses, the influence of the regeneration temperature on the effects of the procedures carried out was compared. It was found that 400°C was too low to effectively clean the binder matrix, but that the more resin in the spent sand, the more intense the cleaning effect. When the required regeneration temperature for furfuryl resin of 523°C was used, higher binder degradation kinetics were observed due to the additional energy supplied to the process from the combustion of a large amount of organic material in the moulding sand.
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Authors and Affiliations

Mariusz Łucarz
1
ORCID: ORCID
Marcini Brzezińsk
1

  1. AGH University of Krakow , Faculty of Fo undry Engineering, Al. Mickiewicza 30, 30-059 Krakow , Poland
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Abstract

The investigation results of the influence of the selected parameters of the thermal reclaimer operations on the temperature changes in the

combustion chamber and the process energy consumption, are presented in the hereby paper. The analysis of the heat treatment was

performed with the application of a fresh foundry sand, since it was assumed that the dominating energy part was used for the grain matrix

heating and due to that, the energy used for burning small amounts of organic binder remained on sand grains could be omitted. Thermal

treatment processes performed under various conditions were analysed from the point of view of a gas consumption and temperatures

obtained in the experimental reclaimer. The recorded data allowed to point out the parameters having essential influence on the process of

the quartz matrix heating in the combustion chamber as a gas consumption function.

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Authors and Affiliations

M. Łucarz
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Abstract

The results of investigations of thermal reclamation of spent moulding sands originating from an aluminum alloy foundry plant are

presented in this paper. Spent sands were crushed by using two methods. Mechanical fragmentation of spent sand chunks was realized in

the vibratory reclaimer REGMAS. The crushing process in the mechanical device was performed either with or without additional

crushing-grinding elements. The reclaimed material obtained in this way was subjected to thermal reclamations at two different

temperatures. It was found that a significant binder gathering on grain surfaces favors its spontaneous burning, even in the case when

a temperature lower than required for the efficient thermal reclamation of furan binders is applied in the thermal reclaimer. The burning

process, initiated by gas burners in the reclaimer chamber, generates favorable conditions for self-burning (at a determined amount of

organic binders on grain surfaces). This process is spontaneously sustained and decreases the demand for gas. However, due to the

significant amount of binder, this process is longer than in the case of reclaiming moulding sand prepared with fresh components.

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Authors and Affiliations

M. Łucarz
M. Dereń
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Abstract

The results of investigations of spent moulding sands taken from the mould at various distances from the surface of the produced casting,

are presented in the paper. The casting mould was made with an application of the cooling system of the metal core in order to increase the

cooling rate of the ladle casting. As temperature measurements in the mould indicated the heat flow from the metal did not create

conditions for the complete burning of a moulding sand. The analysis was performed to find out changes of spent moulding sands caused

by degradation and destruction processes of organic binders. Conditions occurring in the casting mould were discussed on the bases of

testing: ignition losses, dusts contents, pH reactions and the surface morphology of the moulding sand samples. Factors limiting the

effective mould degassing were pointed out. Operations, possible for realization, which can limit the reasons of a periodical occurrence of

increased amounts of casting defects due to changing gas evolution rates being the result of the technological process, were also indicated.

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Authors and Affiliations

M. Łucarz
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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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Authors and Affiliations

M. Dereń
M. Łucarz
A. Roczniak
A. Kmita
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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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Authors and Affiliations

T. Sappinen
J. Orkas
T. Kronqvist
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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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Authors and Affiliations

M. Łucarz

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