In this paper methods of determination of total pyrolytic carbon and its fraction: lustrous and amorphous carbon was shown. They are used in foundry industry as carbonaceous materials, i.e. in coal dust replacements and moulding sands. The principle of model analyser working, which uses NDIR module detection, and example results of such analysis were also presented.
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The article presents the results of investigations, which make a fragment of the broad-scale studies carried out as a part of the statutory activity on optimising the foundry sand technology using new, modified, inorganic binders. The results of investigations regarding the effect of lustrous carbon carriers on the technological properties of foundry sands with inorganic binders were presented in a concise manner. The selected additives were introduced to moulding sands prepared with the new, modified, inorganic binders bonded by the chemical reaction or by blowing with gaseous CO2. Attention was focussed on the effect of selected additives promoting the formation of lustrous carbon on the knocking out properties of moulds and cores prepared from sands with the new types of inorganic binders. The quality of the test castings was also evaluated along with the tendency to the formation of lustrous carbon at the metal - mould interface, basing on the results of microscopic examinations and analysis of the chemical composition using an X-ray microanalyser.
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Model pyrolysis made possible to identify three solid products of carbonaceous additives. Lustrous carbon is the most important form of the pyrolysis carbon. With its structure and physical and chemical properties it comes near to graphite. Amorphous carbon with turbo-stratic lattice, higher oxireactivity, and lower protective function against liquid metal comes near to carbon black. Semicoke also plays a non-negligible role. All forms of carbon have an important representation in oolitized quartz grain also during forming the casting surface. While amorphous carbon is formed directly from the gaseous phase by homogeneous nucleation, lustrous carbon, with regard to similarity of lattices with quartz, is formed by heterogeneous nucleation on grains. High covering power and low oxireactivity give its highest protecting power of the mould face. New experimental equipment made possible to check a possibility of use of new composite bentonite binders containing "process carbon" (graphite, anthracite, amorphous carbon). The BTEX content in exhalations and in waste sands too was considerably decreased with high smoothness of castings.
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