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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 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.

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).

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 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 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.

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.

It was proved experimentally that microwave radiation caused crosslinking of sodium polyacrylate (PAS) / silica gel system, treated in this work as a model molding sand of the type polyacrylate (polymeric binder) / quartz sand (loose matrix). The results of Raman and FT-IR spectroscopic measurements are the base of proposed mechanism of the crosslinking process investigated. According to it, chemical adsorption activated with microwaves plays a significant role. The chemical adsorption leads to formation of strong hydrogen bonds [see equation (1)] or covalent ones [of anhydride type or -C (O)-O-Si, see equations (2) and (3)] PAS - silica. It favors an improvement in tensile properties in comparison with the properties of molding sands hardened traditionally with Ca(OH) 2 and CO 2 . Additional advantages of the hardening method described, with use of microwaves, are short time (90 s) and relatively low temperature (150 °C) of the process.

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 present paper summarises the results of the project: 'Survey of Anthropogenic Sources of Dioxins and Furans in the Baltic Region'. As a part of the project, inventories have been carried out in Estonia, Latvia, Lithuania and Poland by applying the toolkit for quantification of dioxin and furan releases developed by UNEP Chemicals. The main route of direct releases to the environment is emission to air. Total emission to air from Poland was estimated at 490 (88-1,300) g I-TEQ/year, whereas the emissions from Estonia, Latvia and Lithuania were estimated as being 14 (2.4-54), 23 (2.6-63) and 17 (2.6-38) g I-TEQ, respectively. In general, the uncertainty on the estimates is very high, and recommendations regarding further development of the inventories have been made, and measures for reducing the releases have been provided.

Sand binding systems can have a significant impact on the nature of the casting skin formation. In particular, the binder containing elements such as S, O and N may adversely affect the structure of the layer. As in the case of spheroidal graphite cast iron (SGI) and compacted graphite cast iron (CGI) main factor causing the degeneration of graphite in the surface layer of the casting is sulfur, therefore these binding systems (binder) which contain sulfur have been thoroughly discussed here. The following are sand mold technologies: furan, acid catalyzed, phenolic, acid catalyzed, hot box, warm box and Shell (Croning) process. Sand molding with the use of furfuryl resins technology is presented in detail due to their widespread use in casting both cast iron and cast steel. To reduce the thickness of the surface layer, which may be the adverse effect of sulfur on the degeneracy of the graphite, S content in molding sand should be less than 0.15 % mass, and even below 0.07 % mass. Sand binding systems can have a significant impact on the nature of casting skin formation. In the case of green sand, moisture promotes the formation of the ferritic rim (Reisener, Br Foundryman 55:362–369, 1962; Matijasevic et al. Trans AFS 82:571–622, 1974; Narasimha and Wallace, AFS Trans 83:531–550, 1975). Research carried out for sand mold with sodium silicate and phenolic urethane has shown that SGI and CGI castings made in the first sand mold is pearlitic rim occurred, and in the second sand mold this occurrence is not found (Boonmee and Stefanescu, Foundry Trade J 186:225–228, 2012). Regarding the effect of the molding sand on the nature of the casting skin formation, they can be divided into molding sand: with binders containing sulfur (i.e. furfuryl alcohol and urea-formaldehyde resin) and the molding sand that are not bound with binders not containing sulfur (i.e. phenol-urethane resin ). From the point of view of the top layer the sulfur-containing molding sand is much more important, due to its adverse effect on the formation of spheroidal graphite.

The phenomena on the mold/metal interface largely determine the microstructure of the casting surface layer, quality of the surface and casting performance characteristics (mechanical properties, wear resistance , corrosion resistance, etc.). Processes that occur here are of particular importance in the case of cast iron with vermicular or spheroidal graphite performed in sand molds (graphite degradation and graphite depletion ). It is assumed that the direct cause of graphite degradation , resulting in a layer of flake graphite, is the Mg depletion at the surface layer of the casting and the main reason (although not the only) for the decrease of the Mg concentration is the reaction of sulfur and oxygen. To explain this phenomenon, Fe–Mg, Mg–S, Mg–O and Fe–S systems have been discussed. Performed thermodynamic calculations have shown that the magnesium and sulfur and oxygen reactions in liquid iron occur in the gas phase, wherein the thermodynamic reaction of Mg vapors with oxygen gas is more privileged than with the sulfur vapors. To clarify the mechanism of the formation of the surface layer on the casting Stefanescu et al. developed a thermo-diffusion model 2-D. However, this model does not take the kinetic agent and the degree of undercooling during solidification of the casting into account, which affects the amount of primary austenite formed, which may also result in a reduction of the Mg concentration. To reduce the degree of transition of sulfur from molding sand to casting surface layer, the use of protective coatings for molds and cores, containing desulfurization ingredients such as CaO, MgO, talc, or Mg-FeSi, which binds sulfur and supplements magnesium at the same time is preferred.

Many of surface defects in casting are caused by interaction of the metal with the molding sand. These phenomena occurring on the mold/cast interface can be divided into three groups: metal penetration (mechanical, chemical, vapor state, water explosion penetration and eutectic exudation penetration); transition of elements from the molding sand into casting and from the casting into the mold and gas generation by thermal decomposition of the binder and/or coating. Transition of the casting elements such as P, N, H, C, S, Si from the molding sand to the surface layer of the casting and elements such as Mn, C from casting to the molding sand is also possible. Frequently, this can cause changes in the chemical composition of the surface layer of the casting, which may consequently lead to changes in the casting microstructure and properties. Gases emitted from the molding sand, core or protective coating during pouring liquid metal are often due to the cause of the so-called gas porosity. The rate of the evolution of gases from the mold and cores, and their volume depends strongly on the binder used. Air present in the mold cavity may also be the cause of porosity.

Good quality casting that meets the customer's requirements depends on many factors. Generally, these can be classified into two groups, related to metal and the casting mold. However, it may happen that the metal meets all the criteria and the mold is properly made but the quality of the casting can be unsatisfactory. The reason for this may be the phenomena on the interface mold/casting, which are not always taken into account. Processes taking place there are mainly due to the quality of the casting surface, which is very important; especially in the case of castings whose surface is exposed directly to adverse factors (wet corrosion, dry corrosion, wear, etc.). However, processes taking place on the interface mold/casting may also adversely affect the mechanical properties of the casting, e.g., tensile strength, fatigue limits, machinability. This is caused by the degeneration of nodular and compacted/vermicular graphite, or decarburization of the casting surface layer, or the appearance of areas of pearlitic/ferritic rim. Several mechanisms are responsible for the formation of abnormal surface layer on the CGI and SGI castings, which are associated with a reduction in the concentration of either Mg (reaction with S and/or O) or the cooling rate of the casting (formation of austenite layer).

This paper describes findings about the effect of temperature and sulphur content on the surface tension of Fe-C (3.9%)-Si (1.6%) alloy. For measurements of surface tension the sessile drop method was used. The examinations were made on cylindrical specimens of dimensions √ 3.5 x 3.5 mm weighing 0.2 - 0.3 g. Throughout the whole measurement helium of high purity was passed through the furnace. The measurements were carried out at every 50 K over the temperature range of 1523 - 1873 K. Alloys with various sulphur content levels from 0.016 - 0.50% were examined. The relationship between the surface tension of this alloy and temperature (with sulphur content kept constant) can be adequately described by an equation of the type σ = aT2 - bT + c. Two ranges of temperature have been specified: range I of 1523-1773 K when the temperature coefficient dσ/dT>0 and range II of 1773-1873 K when dσ/dT

Results of the measurements of emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in two metallurgical plants representing ferrous metallurgy (an iron ore sintering plant) and non-ferrous metallurgy (a secondary copper smelter) are discussed in the paper. In the case of the secondary copper smelter dioxin concentrations were determined in the range from 0.03 to 8.1 ng TEQ/Nm3 and high variability of emissions was observed, which did not depend on the composition of material fed and the stage of smelting. In the case of measurements carried out in the iron ore sintering plant the concentrations ranged from 0.6 to 1.7 ng TEQ/Nm3. It was found additionally that a well-functioning electrostatic precipitator could reduce PCDD/Fs emissions even by 75% (with respect to the total mass of congeners), while off-gas recirculation had no significant effect on the emissions. The paper contains original results of dioxin emission measurements from a secondary copper smelter plant and an iron ore sintering plant in Poland. In the first plant, high variability of flue gas flow and concentrations of dioxins between successive batches as well as within a single smelting process was found. This problem has never been described in the literature. In the second plant, great stability of dioxin emissions from the iron ore sintering plant and high emission reduction efficiency (about 70%) of dioxins by an electrostatic precipitator were observed. No significant effect of gas recirculation on the PCDD/Fs emission was reported.

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.

During the formation of surface defects in a casting an important part is played by the surface energy and by the phenomenon of wettability of the moulding material by a liquid alloy. The surface t...