Application of microwave energy for curing of molding sands containing oil binders

Abstract This works presents the results of studies concerning possibility of application of microwave heating in the curing process of molding sands containing oil binders. Molding sands prepared with three kinds of binders, that is oils C, DL and Retanol, have been subject to experiments. The sands have been dried with two methods: in a microwave chamber of 750W power and, for comparison, with classical method at the temperature of 200°C for 120 minutes. Tensile and bending strength of the samples have been determined after cooling down. It has been found that microwave drying in the low-power device used for experiments is effective only in case of molding sand prepared with addition of DL binder. The temperature of heated, even up to 32 minutes in a microwave chamber, blocks prepared from the remaining two masses, was insufficient to initiate binding process. The undertaken attempts of binder modification and introduction of additives intensifying microwave heating process allowed for achievement of satisfactory results. It has been found that power of the heating device is the main factor determining efficiency of microwave curing of molding sands containing oil binders. An additional experiment has been conducted on a laboratory workstation allowing for microwave heating of small mass samples with a high output power of magnetron concentrated in a small substrate volume. It has been observed that microwave drying process of molding sands was of dynamic character over a short period of time, not exceeding 120 seconds, thus assuring efficient curing of the sands containing the used oil binders. Therefore, application of devices of properly high microwave output power allows for efficient drying of oil molding sands, while simultaneously assuring the possibility to reduce time and energy consumption necessary for production of foundry cores of proper functional characteristics.

Possibilities of using microwave heating in disposal process of thermo and selfsetting sandmixes

The paper presents a semi-industrial reactor designed for microwave utilization of waste moulds and cores made of moulding sands prepared in furane resin technology. It was found that a possibility exists of effective incinerating this way prepared residues of cores separated from moulding sands or waste moulds left after casting. The preliminary tests evidenced that microwave heating is an effective way of disposing waste moulding sands and the applied apparatus permits effective control of the microwave heating process

Microwave absorption by used moulding and core sands

The paper presents measurement results of standing wave ratio to be used as an efficiency indicator of microwave absorption by used moulding and core sands chosen for the microwave utilization process. The absorption measurements were made using a prototype stand of microwave slot line. Examined were five used moulding and core sands. It was demonstrated that the microwave absorption measurements can make grounds for actual microwave utilization of moulding and core sands

Determination of application possibili- ties of microwave heating in the curing process of water glass molding sands with fluid esters. Part 2

Abstract This article, constituting continuation of the subject discussed in the first part, presents results of the experimental trial of water glass molding sands' curing method modification with application of fluid esters and innovative microwave heating. The research objective was to determine possibilities of microwave application for curing of water glass molding sands prepared with addition of hardening agents sold under the trade name of Mach. After initial chemical curing molding sands, prepared with addition of the above mentioned hardeners, have been heated with microwaves in order to determine their influence on changes of basic technological and strength parameters of the sands, and indirectly on the quality of quartz grains binding. Studies aimed at determination of water content changes in the sands have also been undertaken. As our studies demonstrated, microwave heating allows for quick reduction of water content, thus resulting in improvement of strength parameters such as bending and tensile strength. Application of the combined methods of ester curing and innovative microwave heating facilitates production of high quality foundry moulds and cores, while simultaneously improving mould and core preparation procedures at the foundries and as a result reduces their time to an indispensable minimum

Measurement of gases in the process of microwave utilization of molding sands. Part 1

W artykule przedstawiono wyniki badań gazów, powstałych podczas utylizacji wybranych mas formierskich w reaktorze mikrofalowym, z punktu widzenia ich szkodliwości dla otoczenia. Metodą chromatografii gazowej analizowano gazy z pięciu mas formierskich (cztery ze spoiwem organicznym i jedną z nieorganicznym). Do utylizacji mas formierskich wykorzystano półprzemysłowy reaktor mikrofalowy. Analizując wyniki badań stwierdzono, że nastąpiło przekroczenie wartości największych dopuszczalnych stężeń gazów wytlewnych, określonych w Dyrektywie Unii Europejskiej wskaźnikiem szkodliwości dla otoczenia, jedynie w przypadku masy z żywicą fenolową Fenotec P439.In this work the influence of gases emitted from utilization of molding sand on the enviroment was studied. Five different molding sands were examined by gas chromatographic method. The analysis showed that the utilization of molding sands in the microwaves reactor found larger than allowable concentrations of gases only in the molding sand with phenolic resin Fenotec P439