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.

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.

The paper presents possibility of using biodegradable materials as parts of moulding sands’ binders based on commonly used in foundry

practice resins. The authors focus on thermal destruction of binding materials and thermal deformation of moulding sands with tested

materials. All the research is conducted for the biodegradable material and two typical resins separately. The point of the article is to show

if tested materials are compatible from thermal destruction and thermal deformation points of view. It was proved that tested materials

characterized with similar thermal destruction but thermal deformation of moulding sands with those binders was different.

The obtained results of heating of sand moulds with binders by means of a thermal radiation of liquid metal are presented in this study.

Standard samples for measuring Rg made of the tested moulding sands were suspended at the lower part of the cover which was covering

the crucible with liquid metal (cast iron), placed in the induction furnace. The authors own methodology was applied in investigations. The

progressing of the samples surface layers heating process was determined as the heating time function. Samples of a few kinds of

moulding sands with chemical binders were tested. Samples without protective coatings as well as samples with such coatings were tested.

The influence of the thermal radiation on bending resistance of samples after their cooling was estimated. The influence of several

parameters such as: time of heating, distance from the metal surface, metal temperature, application of coatings, were tested. A very fast

loss of strength of moulding sands with organic binders was found, especially in cases when the distance between metal and sample

surfaces was small and equaled to 10÷15 mm. Then, already after app. 15 seconds of the radiation (at Tmet=1400o

C), the resistance

decreases by nearly 70%. Generally, moulding sands with organic binders are losing their strength very fast, while moulding sands with

water glass at first increase their strength and later slightly lose. The deposition of protective coatings increases the strength of the mould

surface layers, however does not allow to retain this strength after the metal thermal radiation.

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.