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The aim of this paper is the comparison of the thermal destruction course of one of the commercially available binders applied in the ALPHASET technology in dependence of the temperature, heating rate and the character of the atmosphere (inert, oxidising or reducing). The thermogravimetric analysis/differential scanning calorimetry/Fourier-transform infrared spectroscopy (TG/DSC/FTIR) system allowed for real-time analysis of the composition and intensity of gases emitted during slow heating in the inert and oxidising atmospheres. In addition, the TG/DTG/DSC investigation of the binder was performed in the reducing atmosphere. The pyrolysis gas chromatography coupled with mass spectrometry system allowed for the analysis of gases evolved at very fast heating in the inert atmosphere (pyrolysis) as a function of temperature. It has been proven that the type and amount of the gases emitted is highly dependent on the temperature, heating rate and the atmosphere in which it is performed. The highest versatility of harmful volatiles is produced during heating in the inert atmosphere. This type of atmosphere is present in the closest proximity of the liquid metal. Thus, to reduce the risk of exposure of the foundry workers, the extraction of the casting should be done under the hood, and sufficient personal protective equipment should be used.

Kinetic characterization of the degradation of resins is important for understanding structural changes, which occur during the different phase of degradation, and study of that can help predict and improve the industrial performance of the resin. Thermal decomposition behavior of commercial binder based on phenol–formaldehyde (PF) resin, using in metal casting were studied using a conventional dynamic thermogravimetric analysis TGA/DTG at different heating rates s: 5, 10, 20 and 30 °C/min under inert atmosphere. The kinetic parameters of thermal degradation of PF binder were investigated using model-free methods: integral Kissinger-Akahira-Sunose (KAS) and differential method after Friedman as well as the model-based method. The initial kinetic parameters values for nonlinear model-fitting were taken from the model-free evaluations. Activation energy is a kinetic parameter that reflects the sensitivity of the resin to temperature. The thermal stability of samples was estimated by measuring the degradation temperature, which was calculated according to the maximum reaction rate criteria.

The assessment of the harmfulness of moulding and core sands is mainly based on investigations of compositions of gases emitted by liquid casting alloys during the mould pouring. The results of investigations of moulding sands obtained under industrial conditions are presented in this paper. A unique research stand was designed and built for this aim. It allowed us to determine emissions of gases at individual stages of casting a mass up to 50 kg. This approach enables simulation of foundry conditions. Moulding sands bound by organic binders (phenol-formaldehyde, furan), inorganic binders and green sand, were subjected to investigations. The composition of gases that evolved during the individual stages, pouring, cooling and knocking out, was tested each time, and the contents of Polycyclic Aromatic Hydrocarbons (PAHs) and benzene, toluene, ethylbenzene, and xylenes (BETX) were analysed. Investigations indicated that the emission of gases from sands with inorganic binders is negligible when compared with the emission of gases from sands with organic binders. The emission of gases from green sand is placed in the middle of the scale. As an example: the sand with furan resin emitted 84 mg of BTEX (in recalculation for 1 kg of sand) while from sands with inorganic binders there was a maximum of 2.2 mg (for 1 kg of sand). In the case of sands with inorganic binders, MI and MC sands indicated comparable and very low emissions of gases from the PAHs group, at the level of 0.018 mg and 0.019 mg for 1 kg of sand, respectively. The higher emission of PAHs from MG sand is the result of its different way of hardening (a binder was of an organic character) than of sands MI and MC.

The article presents the results of research on thermal decomposition of Ester-Cured Alkaline Phenolic No-Bake (ALPHASET) binders used in molding technology. In the ALPHASET system phenol-formaldehyde resin of resole type is cured with a liquid mixture of esters. Under the influence of the molten metal the thermal decomposition of the binder follows, resulting in the evolution of gases, often harmful, e.g. from benzene, toluene, ethylbenzene and xylenes (BTEX) or Polycyclic Aromatic Hydrocarbon (PAH) groups. The identification of gases evolved during the pyrolysis of the binders was carried out and their decomposition temperatures were determined using the Thermogravimetry–Gas Chromatography–Mass Spectrometry (TG–GC–MS) technique. The tests were subjected to two types of binders from different manufacturers. Among the products of pyrolysis there have been identified mainly benzene and its derivatives, and phenol and its derivatives. Compounds identified in pyrolytic gas are largely considered to be harmful to humans and the environment (some of the compounds are carcinogenic and mutagenic). The presented results of the TG–GC–MS measurements show that the applied analytic methods are feasible to perform a qualitative and also quantitative characterization of the binder samples.

Increased application of organic compounds, mainly in form of synthetic resins, used as binders for moulding and core sands in metal casting, may have an adverse effect on the environment and work conditions in foundry plants. In this article we focused on the identification of the degradation products formed during laboratory scale simulation of complex thermal degradation of commercial binder. For our investigation we have chosen the phenol-formaldehyde based resin hardened by a mixture of organic esters (PFRE) as it is widely used in the core and mould sand technology. The identified degradation products obtained during the experiments varied depending on mechanism used for pyrolysis. In the “slow” evaluation, simple compounds such as: CO, CO2, NH3, H2O, phenol and CH4 were generated. Meanwhile, during the “flash” pyrolysis (500, 700, 900 and 1100 °C), mainly phenol and its methyl and ethyl derivatives as well as benzene were released. It was determined that the pyrolysis products and their ratio depended on the temperature during the degradation process.

There are two methods to produce primary copper: hydrometallurgical and pyrometallurgical. Copper concentrates, from which copper matte is melted, constitute the charge at melting primary copper in the pyrometallurgical process. This process consists of a few stages, of which the basic ones are roasting and smelting. Smelting process may be bath and flash. Slag from copper production, on the end of process contain less 0,8%. It is treat as a waste or used other field, but only in a few friction. The slag amount for waste management or storage equaled 11 741 – 16 011 million tons in 2011. This is a serious ecological problem. The following slags were investigated: slag originated from the primary copper production process in the flash furnace of the Outtokumpuja Company in HM Głogów 2 (Sample S2): the same slag after the copper removal performed according the up to now technology (Sample S1): slag originated from the primary copper production process in the flash furnace of the Outtokumpuja Company in HM Głogów 2, after the copper removal performed according the new technology (Sample S3). In practice, all tested slags satisfy the allowance criteria of storing on the dumping grounds of wastes other than hazardous and neutral.

A special Slag-Prop Cu database has been developed to archive data from laboratory and industrial tests related to post-reduction slags. In order to enrich the data areas, it was decided to design a system for measuring the temperature of the liquid slag and its viscosity. Objectives of research work are to gather information on the properties of post-slags such as the temperature of liquid slag and its viscosity. The discussed issues are especially important in the foundry practice. Designed research stand and using of database applications can greatly facilitate the work of metallurgists, foundrymen, technologists and scientists. The viscosity measurement was developed and presented earlier. The author’s analytical methodology was supplemented by a thyristor measuring system (described in the article). The system temperature measurement can be performed simultaneously in 3 ways to reduce the measurement error. Measurement of the voltage mV - using the Seebeck effect can be measured throughout the entire range of thermocouple resistance, up to 1300 °C. Direct temperature measurement °C - measurement only below 1000 °C. Additional measurement - the measurement can also be read from the pyrometer set above the bath. The temperature and the reading frequency depend on the device itself. The principle of measurement is that in a molten metal / slag crucible, we put a N-type thermocouple. The thermocouples are hung by means of a tripod above the crucible and placed in a crucible. The thermocouple is connected to a compensating line dedicated to this type of thermocouple. The cable is in turn connected to a special multimeter that has the ability to connect to a computer and upload results. Temperature measurement can be performed simultaneously in 3 ways to reduce the measurement error. The Sn-Pb alloy has been subjected to testing for proper operation of the device. In this foot should be observed the supercooling of the liquid, which initiates the crystallization process and in which latent heat begins to exude raising the temperature until the coagulation temperature is reached.

The Electro Slag Remelting (ESR) is one of the remelting processes in the field of metal refinery. In this process, the slag plays various roles, such as heat generation, protection of melt, and chemical refining. The main objective of the experiments described in this article was to identify the most appropriate slag composition for the electro slag remelting of the steel in order to achieve the chemical composition compliant with the standard applicable to the given steel, minimum sulphur content, minimum contents of oxide and sulphide inclusions, as well as mechanical properties corresponding to the standard applicable to the steel STN 14 109. Ten electrodes were remelted, whereas the remelting was carried out under 8 slags. The used slags containing 70% of CaF2 and 30% of Al2O3 with different addition of CaO, the slags consisted of the same components as previous slags, whereas the ratio of individual components was 1:1:1, and with SiO2 and MgO and slag without Al2O3. With regard to all the above mentioned facts, the slag types which may be regarded as the most appropriate for the STN 14 109 steel remelting are the basic slags containing 70% of CaF2 - 30% of Al2O3 with added 30 and 45 weight % of CaO.

A molding sand hardening in these processes occurs as a result of the influence of a catalyst or hardener, in a gaseous form, on components of binding materials at a room temperature. This group contains the following technologies: phenolic–furan resin/SO2 (Hardox), phenolic–urethane cold-box resin (PUCB), resole resin/CO2 system, acryl/epoxy resin/SO2, and FRC process (free radical curing). Since in this technological group apart from inert gases also harmful and toxic gases are applied, these processes require special care. Therefore the development of the new process, applying gases harmless for human organisms and the environment, is necessary.

The presented principles of organic chemistry should be helpful in understanding reactions and processes occurring during the molding sand preparation, mold forming, pouring with liquid metal and casting knocking out. Knowledge of these processes is especially important for the description of effects occurring when liquid metals influence molding sands and are related to the destructions of binders.

Technologies of producing molds and cores used for producing castings of special alloys, of complicated shapes and high functional properties, are described. Castings manufactured in these processes, mainly for the cosmic, aircraft, automotive, and armament industry, are of the highest quality. The Rapid Prototyping (RP) process deserves a special attention. The base of the whole process is the digital 3D model made in the CAD environment. The RP is the additive method, which means it is based on a gradual placement of a material, layer after layer. This process is very efficient in small series and in piece production.

A majority of contaminations generated in the casting production is related to molding and core sands: preparation of sands, producing of molds and cores, mold pouring with molten metals, mold cooling and knocking out, and reclamation of spent molding sands. Dangerous chemical substances depend on molding sands composition, liquid metal temperature, and the atmosphere in molds. Several evolving substances have carcinogenic or mutagenic influence (PAHs, BTEX), being hazardous for employees. At the economical utilization of spent molding sands, the attention should be drawn to the possibility of elution of dangerous substances from these sands.

Generally cores are produced by the same techniques as molds. Small- and medium-size cores are often blown or shot into the core box. Molding sands can differ from each other according to their composition, binding methods, and consistency. A few systems, taking into account dividing of sands in dependence of the assumed criterion, were developed. Molding sands can be divided in dependence of their destination, the function which they have in molds, or a wear degree. Assuming the chemical character of the binding material as the criterion, there are inorganic or organic binders. The temperature, at which a hardening process of binders occurs, can be also the dividing criterion: room temperature, increased temperature, or high temperature.

The application of protective fire-resisting coatings on cores is the basic condition of obtaining castings of the required surface quality. Coatings used for molds and cores can have specific properties in dependence on their destination: passive coatings, reinforcing coatings, and active coatings. Water or alcohol can be solvents of liquid coatings.

The matrix is the basic component of molding and core sands. Natural sands (quartz, zirconium, chromite, olivine) as well as synthetic sands are used as matrices. The most often a quartz sand is used; however it has several drawbacks: low-melting temperature, high linear and volumetric dilatability as well as phase transformations.

GEOPOL® is a unique inorganic binder system. This technology is currently used in the foundries for three basic production technologies: (a) self-setting molding sand, (b) molding sand hardened by gaseous CO2, (c) and the hot-box technology by hot air hardened.

Molding sands with water glass belong to the group of sands which are human and environment-friendly. Water glass as a binder of molding sands has been known since the middle of the twentieth century. Irreversible reactions, occurring between water glass and liquid hardeners (organic esters) or CO2, are applied for molding sand hardening. In order to improve disadvantageous properties of these sands (e.g., bad knocking out), water glass is subjected to physical or chemical modifications. As a result of such modifications, the water glass-based new binders, environmental-friendly, are formed. The known world companies from many years are performing investigations of molding sands (CORDIS®, Huttenes Albertus; INOTEC®, ASK Chemicals; AWB®, Minelco), where water glass hardening occurs as a result of warming core boxes and core blowing by hot air.

Molding sand hardening in these technologies occurs as a result of warming of sand and resin mixture, or more often by contact of this mixture with warmed pattern system. All processes of this type assure good dimensional accuracy, provided that good-quality patterns (metal), which can be very expensive, are used. On account of this, processes with hardening at high temperature are applied for producing cores of limited dimensions, mainly in the mass production. Their application, widely popularized for years, is presently in a falling phase, since they are being substituted by technologies where hardening is performed by a gaseous factor, less energy-consuming.

This article presents qualitative and quantitative analysis of the waste produced by KGHM Polska Miedź. The waste has been analyzed according to its chemical composition and balanced in order to be reused and recycled. Special attention has been paid to mining industries producing the biggest amount of waste and ore enrichment businesses generating waste, which isn’t reused nowadays. Laboratory reseach has been conducted on floatation waste, different kinds of slags, waste gases and water slag extracts. Attention has been drawn to the possibility of using a computer program SLAG - PROP for analyzing physicochemical features, technological features and the refining of the acquired waste. Consequently, the further way of utilization of waste has been shown. From this point of view, analyses of DTA and TG slags in an oxide coating seem especially interesting. Having a particular composition they can be successfully utillised in the refining processes of copper pyrometallyrgy.

Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. These resins in their initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin, under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene), and also polycyclic aromatic hydrocarbons (PAHs) can be formed and released. The aim of the study was the development of the method, selection of analytical methods and the determination of optimal conditions of formation compounds from the BTEX and PAHs group. Investigations were carried out in the specially designed set up for the thermal decomposition of organic substances in a temperature range: 500 – 1 300°C at the laboratory scale. The object for testing was alkyd resin applied as a binding material for moulding sands. The qualitative and quantitative analyses of compounds were performed by means of the gas chromatography coupled with the mass spectrometry (GC/MS).

The results concerning emission of gases from two commercial graphite protective coatings for moulds and cores (water and alcoholic) are given in the hereby paper. Investigations were performed in two systems. One of the systems was corresponding to conditions occurring inside the mould cavity immediately after its pouring with liquid metal (Method 1), while the second was simulating conditions deep inside the mould at a certain distance from the casting (Method 2). Investigations were carried out in the CO2 atmosphere and in the air. The water protective coating generated 1.5 to 3 times larger volume of gases than the alcoholic coating (in dependence on the measuring method and atmosphere). The smallest differences occurred in the air atmosphere, while the largest in the CO2 atmosphere.

Zinc ferrite ZnFe2O4 both in the micro and nano scale is widely used in various fields. The article discusses the structure of this compound and its properties in the nanoscale, which is clearly different from those which the ferrite shows in the microscale. The properties of dust generated electric arc furnace, which can contain up to 40% zinc, substantially in the form of ZnFe2O4 are disscused here. Specific properties (electric, magnetic, thermal) of zinc ferrite nanoparticles determine the very wide possibilities of their use, inter alia as catalysts, absorbents, gas sensors, and a tool to combat cancer.

The furan resin offers advantages such as high intensity, low viscosity, good humidity resistance and is suitable for cast different casting alloys: steel, cast iron and non-ferrous metal casting. For hardening furan resins are used different hardeners (acid catalysts). The acid catalysts have significant effects on the properties of the cured binder (e,g. binding strength and thermal stability) [1 - 3]. Investigations of the gases emission in the test foundry plant were performed according to the original method developed in the Faculty of Foundry Engineering, AGH UST. The analysis is carried out by the gas chromatography method with the application of the flame-ionising detector (FID) (TRACE GC Ultra THERMO SCIENTIFIC).

Increasingly strict regulations, as well as an increased public awareness, are forcing industry, including the foundry industry, to develop new binders for molding sands, which, while being more environmentally friendly, would simultaneously ensure a high quality of castings. Until recently, binders based on synthetic resins were considered to be such binders. However, more accurate investigations indicated that such molding sands subjected to high temperatures of liquid metal generated several harmful, even dangerous substances (carcinogenic and/or mutagenic) from the benzene, toluene, ethylbenzene and xylenes (BTEX) and polycyclic aromatic hydrocarbons groups (PAHs). An assessment of the most widely used molding sands technologies at present with organic binders (synthetic resins) from the no-bake group (furan no-bake and phenolic-ester no-bake) and their harmfulness to the environment and work conditions is presented in this paper. In the first stage of this research, gases (from the BTEX and PAHs groups) emitted when the tested molds were poured with liquid cast iron at 1350 &deg, C were measured (according to the authors&rsquo, own method). The second stage consisted of measuring the emission of gases released by binders subjected to pyrolysis (the so-called flash pyrolysis), which simulated the effects occurring on the boundary: liquid metal/molding sand. The gases emitted from the tested binders indicated that, in both cases, the emission of harmful and dangerous substances (e.g., benzene) occurs, but, of the given binder systems, this emission was lower for the phenolic-ester no-bake binder. The obtained emission factors of BTEX substances show higher values for furan resin compared to formaldehyde resin, for example, the concentration of benzene per 1 kg of binder for furan no-bake (FNB) was 40,158 mg, while, for phenol-formaldehyde no-bake (PFNB), it was much lower, 30,911 mg. Thus, this system was more environmentally friendly.

The influence of the use of moulding sand with furan resin, prepared both with fresh sand and reclaimed matrix, on the formation of a flake graphite formation at the surface layer of ductile iron castings has been investigated. A series of experimental heats of ductile iron cast in moulds made of moulding sand characterised by different levels of surface active elements (sulphur, oxygen) were performed. The effect of the wall thickness and the initial temperature of the metal in the mould cavity on the formation of flake graphite in the surface layer of the casting is shown in the paper. Investigations carried out by means of scanning electron microscopy (energy dispersive X-ray spectroscopy and wavelength dispersive X-ray spectroscopy) showed concentration of gradient profiles of surface active elements in the castings surface layer, which are responsible for their quality. Finally, it has been shown that there exists a significant effect of the quality of the sand on the formation of the flake graphite ...

The problem related to the management of post reclamation dusts generated in the reclamation process of waste moulding sands with organic binders is presented in the hereby paper. Waste materials generated in this process are products hazardous for the environment and should be utilised. The prototype stand for the utilisation of this dangerous material in its co-burning with coal was developed and patented in AGH in Krakow. The stand was installed in one of the domestic casting houses. As the utilisation result the transformed waste product is obtained and its management in the production of ceramic materials constitutes the subject of the presented publication.

The harmfulness assessment of moulding sands with a geopolymer binder and a new hardener, in an aspect of the emission of substances from the BTEX group, was performed. Within the expedience project the new series of hardeners for the inorganic GEOPOL binder was developed. Before the introduction of the new system of moulding sands it was necessary to estimate their influence on the environment. To this aim the gasses emission from moulding sands subjected to the influence of liquid cast iron was tested with regard to the content of the gases from the BTEX group (benzene, toluene, ethylbenzene and xylenes). For the comparison the analogous investigations of the up to now applied moulding sands with the geopolymer binder, were performed. It was found that both systems of moulding sands binding emit similar amounts of gases, as well as similar amounts of substances from the BTEX group. Moulding sands with the GEOPOL binder are much more environmentally friendly than moulding sands with organic binders. The content of the BTEX group substances in gases emitted from moulding sands with the GEOPOL binder was approximately 10-times lower than in case of the moulding sands with organic binders.

The after reclamation dusts originated from various foundry plants, applying moulding sands with organic binding agents, mostly resins, are characterised by different properties in dependence of the used binders, reclamation systems, spent sands overheating degree and the efficiency of the system dedusting the reclaimed material operating in individual foundry plants.In the article the results of investigations of physicochemical properties and thermal utilisation possibility referring to six kinds of after reclamation dusts generated in the mechanical reclamation process of spent moulding sands with furfuryl resins and six other kinds of after reclamation dusts obtained from reclamation process of spent moulding sands with alkaline resins have been presented. All tested dusts originated from various Polish foundry plants of cast iron and cast steel applying the mechanical reclamation process of moulding sands with resins, obtained from different producers.

The investigation results of the influence of the reclaim additions on the properties of moulding sands with the GEOPOL geopolymer binder developed by the SAND TEAM Company were presented. Two brands of hardeners were applied in the tested compositions, the first one was developed by the SAND TEAM Company, marked SA72 and the new hardener offered by the KRATOS Company, marked KR72. The main purpose of investigations was to determine the influence of reclaim fractions and the applied hardener on the basic moulding sands properties, such as: bending and tensile strength, permeability and grindability. The unfavourable influence of the reclaim additions into moulding sands on the tested properties as well as an increased hardening rate, were found. Moulding sands, in which the hardener KR72 of the KRATOS Company was used, were less sensitive to the reclaim additions

Castings constitute important installation elements in the traditional coal, gaseous or nuclear power plants. Cast elements are also used in installations of the so-called renewable energy. Utilising nanoparticles in the foundry industry leads to improvements in the quality of produced castings and thus to the cost production lowering. Better properties of moulds and cores were achieved as a result of utilisation of nanoparticles in sand technologies. Works carried out in the Faculty of Foundry Engineering, AGH-UST, concerned the water-glass binder modification by nanoparticles of metal oxides (zinc oxide and magnesium oxide) in alcoholic solvents (methanol, ethanol and propanol). Nanoparticles were synthesised in the electrochemical process by anodic dissolution of metals as well as by the thermal method. The nanoparticles of zinc oxide obtained in the electrochemical process are of the structure of equiaxial agglomerates of various sizes depending on the applied alcohol. The largest nanoparticles were obtained from the methyl alcohol solution (~50 nm), while the smallest (≤20 nm) from the propyl alcohol solution. The highest tensile strength (above 25% larger than the strength of the moulding sand with no modified water-glass) was obtained by the moulding sand in which water-glass was the binder modified by the colloidal solution of zinc oxide nanoparticles in propyl alcohol.

The results of investigations of moulding sands with an inorganic binder called GEOPOL, developed by the SAND TEAM Company are presented in the paper. Hardeners of various hardening rates are used for moulding sands with this binder. The main aim of investigations was determination of the influence of the hardening rate of moulding sands with the GEOPOL binder on technological properties of these sands (bending strength, tensile strength, permeability and grindability). In addition, the final strength of moulding sands of the selected compositions was determined by two methods: by splitting strength and shear strength measurements. No essential influence of the hardening rate on such parameters as: permeability, grindability and final strength was found. However, the sand in which the slowest hardener (SA 72) were used, after 1 hour of holding, had the tensile and bending strength practically zero. Thus, the time needed for taking to pieces the mould made of such moulding sand will be 1.5 - 2 hours.

The paper presents the results of investigations of the influence of the quality of moulding sand with furfuryl resin hardened by paratoluenosulphonic acid, on the formation of microstructure and surface quality of ductile iron castings. Within the studies different moulding sands were used: moulding sand prepared with fresh sand and moulding sands prepared with reclaimed sands of a different purification degree, determined by the ignition loss value. Various concentrations of sulphur and nitrogen in the sand moulds as a function of the ignition loss were shown in the paper as well as the gas emission and gas evaporation rate from the moulding sands. A series of experimental melts of ductile iron in moulds made of moulding sand characterized by different levels of surface-active elements (e.g. sulphur) and different gas evolution rates were performed. It was shown that there exist a significant effect of the quality of the sand on the formation of the graphite degeneration layer.

Out of moulding and core sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. Depending on the kind of the applied resin under an influence of a temperature such compounds as for example BTEX group and polycyclic aromatic hydrocarbons (PAHs) can be formed and released. During storing or economic utilization of used sand is possibility of eluting harmful substances into the environment. Therefore at assessing an influence of the used sand on the environment two above elements should be taken into consideration. Only such investigations provide the complete assessment of the given sand harmfulness.

The assessment of harmfulness of two resins applied as a partial substitute of coal dust in moulding sands with bentonite - was performed in the paper. The emission value of compounds from the PAH and BTEX groups was assumed as the main harmfulness criterion. Also mixtures of the Kormix type prepared with additions of these resins were tested. Experiments were carried out in an argon atmosphere in a temperature range: 500-1300°. The obtained emission values of these substances were recalculated for 1% of lustrous carbon content in each carrier. It was assumed in the calculations, that the NW 1 and NW 2 carriers contain approximately 55% of lustrous carbon while the Kormix mixture approximately 15%. The critical temperature of forming compounds of the PAH group for the NW 1 carrier is 900°, while for the NW 2 carrier is 1100° (this is a temperature, at which the emission abruptly increases). In case of formation of compounds from the BTEX group the critical temperature for both lustrous carbon carriers is a temperature of 900°.

High-manganese cast steels are characterised by a high abrasion resistance under friction conditions with a simultaneous influence of pressure and impacts. This cast steel is especially suitable for castings of excavator’s scoops, track links, streetcars crossovers, parts of crushers and mills for braking up of hard materials [1-4]. In order to obtain high quality castings of high-manganese cast steels in moulds on the high-silica sand matrices it is necessary to apply protective coatings, which prevent a direct contact between metal and matrix (SiO2). Manganese after being poured into a mould can undergo a partial oxidation forming MnO, which reacts with silica. As a result low-melting manganese silicates are formed, which in a form of a tight layer adhere to the casting surface, significantly increasing a labour input related to cleaning. Three kinds of protective coatings were tested: zirconium, corundum and magnesite. As a base moulding sands on high-silica sand matrices with three kinds of resol resins were applied. The quality of the obtained casting surface was assessed in dependence of the protective coating and resin kind and also in dependence of the metallostatic pressure value.

The paper presents the results of investigations of the influence of the quality of molding sand with furan resin hardened by paratoluenesulfonic acid, on the formation of microstructure and surface quality of ductile iron castings. Within the studies different molding sands were used: molding sand prepared with fresh sand and molding sands prepared with reclaimed sands of a different purification degree, determined by the ignition loss value. Various concentrations of sulfur and nitrogen in the sand molds as a function of the ignition loss were shown in the paper. A series of experimental melts of ductile iron in molds made of molding sand characterized by different levels of surface-active elements (e.g., sulfur) and different gas evolution rates were performed. It was shown that there exists a significant effect of the quality of the sand on the formation of the graphite degeneration layer.

When cast steel castings are made in moulding sands on matrices of high-silica sand, which has a low fire resistance the problem of the so-called chemical penetration is distinctly visible. Whereas this effect appears to a small degree only when moulding sand matrices are of chromite, zircon or olivine sands. Therefore in case of making castings of high-manganese cast steel (e.g. Hadfield steel) sands not containing free silica should be applied (e.g. olivine sand) or in case of a high-silica matrix protective coatings for moulds and cores should be used. Two protective coatings, magnesite alcoholic (marked as coating 1 and coating 2) originated from different producers and intended for moulds for castings of the Hadfield steel, were selected for investigations. Examinations of the basic properties were performed for these coatings: viscosity, thermal analysis, sedimentation properties, wear resistance. In order to estimate the effectiveness of protective coatings the experimental castings were prepared. When applying coating 1, the surface quality of the casting was worse and traces of interaction between the casting material (cast steel) and the coating were seen. When protective coating 2 was used none interactions were seen and the surface quality was better.

A determination of the heating degree of the moulding sand with bentonite on the grounds of simulating investigations with the application of the MAGMA program, constitutes the contents of the paper. To this end the numerical simulation of the temperature distribution in the virtual casting mould was performed. It was assumed that the mould cavity was filled with a moulding sand with bentonite of a moisture content 3,2 % and bentonite content 8 %. A computer simulation can be used for predicting the heating degree of moulding sands with bentonite. Thus, prediction of the active bentonite (montmorillonite) content in individual layers of the overheated moulding sand can be done by means of the simulation. An overheating degree of a moulding sand with bentonite, and thus the bentonite deactivation depends on a temperature of a casting alloy, casting mass, ratio of: mass : masscasting, moulding sand amount in the mould and contact area: metal - mould (geometry of the casting shape). Generally it can be stated, that the bentonite deactivation degree depends on two main factors: temperature of moulding sand heating and time of its operation.

Suitability of the given binding agent for the moulding sands preparation depends on the one hand on the estimation of technological properties of the sand and the mould made of it and the obtained casting quality and on the other hand on the assessment of this sand influence on the natural and working environment. Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. If in the initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin (phenol-formaldehyde, urea, furfuryl, urea-furfuryl, alkyd) under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene), and also polycyclic aromatic hydrocarbons (PAH) can be formed and released. The aim of the study was the development of the method, selection of analytical methods and the determination of optimal conditions of formation compounds from the BTEX group. An emission of these components constitutes one of the basic criteria of the harmfulness assessment of binders applied for moulding and core sands. Investigations were carried out in the specially designed set up for the thermal decomposition of organic substances in a temperature range: 5000C - 13000C at the laboratory scale. The object for testing was alkyd resin applied as a binding material for moulding sands. Within investigations the minimal amount of adsorbent necessary for the adsorption of compounds released during the decomposition of the resin sample of a mass app. 15 mg was selected. Also the minimal amount of solvent needed for the desorption of compounds adsorbed in the column with adsorbent was found. The temperature range, in which the maximal amounts of benzene, toluene, ethylobenzene and xylenes are released from the resin, was defined. The qualitative and quantitative analyses of compounds from the BTEX group were performed by means of the gas chromatography combined with the mass spectrometry (GC/MS).

The results of investigations of three calcium bentonites, activated by sodium carbonate, applied in the foundry industry as binding material for moulding sands, subjected to the influence of high temperatures – are presented in the paper. Investigations were performed by the thermal analysis (TG) method, the infrared spectroscopy (FTIR) method and the modern Cu(II)–TET complex method (used for the determination of the montmorillonite content in bentonite samples). The occurrence of the dehydration process and two-stage dehydroxylation process was confirmed only for bentonite no. 2. This probably indicates that cis- and trans-isomers are present in the octahedric bentonite structure. Tests were performed at temperatures: 500, 550, 700, 900, 1000, 1100, 1200 °C.

The course of the crosslinking process of poly(sodium acrylate) (PAS), used as a binder for molding sands made of olivine sand as a matrix, was studied with use of FT-IR and Raman spectroscopic methods. Three methods of hardening were applied: classical, with use of Ca(OH) 2 + CO 2 system, and in more innovative way by microwave or UV radiation. It was found, on the basis of analysis of spectra obtained (Fig. 1-6), that the PAS crosslinking agent significantly influenced the reaction course. Namely, the Ca(OH) 2 + CO 2 system caused ionic bonds' formation while microwave radiation led to formation of covalent bonds with part of silanolic groups of matrix surface layer. In case of hardening by UV radiation, the product of complicated crosslinked structure occurs because of the reactions of active radicals formed in the polymer. Compressive strength (R u c ) of molding sands hardened with the methods mentioned above has been evaluated (Fig. 7). The samples hardened with microwaves showed the highest values of R u c .

Bentonite is used in a wide range of applications. One of them is the foundry industry. The aim of this study was to investigate modification of moulding sands by dust which is generated during foundry process. Recycling of this dust is very important from ecological point of view. The samples of moulding sands were examined by Fourier Transform Infrared spectroscopy (FTIR). Analysis of the bands due to the Si–O stretching vibrations allows to reveal the changes of active bentonite and silica sand, i.e. the main components of the moulding sands. FTIR results are compared with technological properties of the materials studied. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods have been used as the complementary measurement.