A. Kmita

Influence of a Reclaimed Sand Addition to Moulding Sand with Furan Resin on Its Impact on the Environment

Metalcasting involves having a molten metal poured in a hollow mould to produce metal objects. These moulds are generally made of sand and are chemically bonded, clay-bonded, or even unbounded. There are many binder systems used. Binders based on furfuryl resins constitute currently the highest fraction in the binders no-bake group. Moulding sand, after knocking out the cast, is partially reclaimed, and the remaining part, known as waste foundry sand is used or stored outside the foundry. In this case, the environment hazardous organic compounds and metals can be leached from the moulding sand, thus causing pollution of water and soil. Also during the casting moulds with molten metal, they emit pyrolysis gases containing many different compounds, often dangerous from the BTEX and PAH group, which has adverse impacts on the environment and workers. The article presents the results of research on the impact of the regenerate addition to the moulding sand matrix on emitted gases and the degree of threat to the environment due to leaching of hazardous components. Therefore, for the total assessment of the moulding sands harmfulness, it is necessary to perform investigations concerning the dangerous substances elution into the environment during their management and storage, as well as investigations concerning emissions of hazardous substances (especially from the BTEX and PAHs group) during moulds pouring, cooling, and casting knocking out. Both kinds of investigations indicated that reclaimed sand additions to moulding sands have significantly negative influence on the environment and working conditions.

The influence of motorisation on the climate warming

The automotive industry is under continual pressure because of the harmful effects of cars on the environment. Highly developed countries must implement programs related to the efficient use of fuel. One way to do this is to reduce vehicles weight, where an important role is played by the foundry industry, searching for new construction materials, with a lower specific gravity and suitable mechanical properties. The paper discusses the materials for the automotive industry: spheroidal graphite cast iron (SGI), compacted graphite cast iron (CGI), grey cast iron (FGI), aluminium alloys and magnesium alloys, comparing their functional properties, important from the point of view of their use as automotive castings. An assessment was performed of the impact of the aforementioned casting materials on the environment based on life-cycle analysis of the product.

Reclaiming Ability of Spent Sands with Modified, Hydrated Sodium Silicate

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, tensile strength Rm) after samples storing times: 1h, 2h, 4h and 24 hours.