Until now, the mould sand in general use in the foundry industry are based on bentonite, which resulted from the fact that a good recognition properties and phenomena associated with this material. Come to know and normalized content of montmorillonite and carbonates and their important role in the construction of bentonite, and mass properties of the participation of compressive strength or scatter. Halloysite is widely used in industry and beyond them. However, little is known about its use in the foundry in Poland and abroad. This article presents preliminary research conducted at the Foundry Department of Silesian University of Technology on this material. Will raise the question of the representation of this two materials, which contains information connected with history and formation of materials, their structure and chemical composition. In the research, the results of compressive strength tests in wet masses of quartz matrix, where as a binder is used halloysite and bentonite in different proportions.

The aim of the study was to determine the applicability of a new product added to water glass-containing foundry sands hardened with

ethylene glycol diacetate. The new additive designated by the symbol "B" is a composition of aqueous solutions of modified polyalcohols,

improving the sand knocking out properties. The scope of studies included testing various mechanical and technological properties

of foundry sand mixtures, such as permeability, friability, life cycle of cores and knocking out properties.

In the technological studies, two types of water glass with different values of the silica modulus and density, designated as R145 and R150,

were used. Moulding sands were prepared with the additive "B". For comparison, reference sands with water glass but without the additive

"B" were also made. In Part I of the article, the results of studies of the effect of additive "B" on the properties of foundry sands with water

glass hardened by CO2 blowing were discussed.

Modern investigation methods and equipment for the quality estimation of the moulding sands matrices with organic binders, in their circulation process, are presented in the paper. These methods, utilising the special equipment combined with the authors investigation methods developed in the Faculty of Foundry Engineering, AGH the University of Science and Technology, allow for the better estimation of the matrix quality. Moulding sands systems with organic binders require an in-depth approach to factors deciding on the matrix technological suitability as well as on their environmental impact. Into modern methods allowing for the better assessment of the matrix quality belongs the grain size analysis of the reclaimed material performed by means of the laser diffraction and also the estimation of the moulding sand gas evolution rate and identification of the emitted gases and their BTEX group gases content, since they are specially hazardous from the point of view of the Occupational Safety and Health.

Using the available analytical methods, including the determination of chemical composition using wavelength-dispersive X-ray

fluorescent spectroscopy technique and phase composition determined using X-ray diffraction, microstructural observations in a highresolution

scanning microscope equipped with an X-ray microanalysis system as well as determination of characteristic softening and

sintering temperatures using high-temperature microscope, the properties of particular chromite sands were defined. For the study has been

typed reference sand with chemical properties, physical and thermal, treated as standard, and the sands of the regeneration process and the

grinding process. Using these kinds of sand in foundries resulted in the occurrence of the phenomenon of the molding mass sintering.

Impurities were identified and causes of sintering of a moulding sand based on chromite sand were characterized. Next, research methods

enabling a quick evaluation of chromite sand suitability for use in the preparation of moulding sands were selected.

The cumulative results of investigations of the possibility of using the reclaimed materials after the mechanical, thermal or

mechanical-thermal reclamation for making cores by means of the blowing method in the alkaline CO2 technology, are

presented in the paper. Three kinds of spent sands: with furfuryl resin, bentonite and alkaline phenolic resin, obtained from

the foundry, were subjected to three kinds of reclamation: mechanical, thermal and combined mechanical-thermal, applying

for this aim adequate experimental devices. The obtained reclaims were assessed with regard to the degree of the matrix

liberation from the determined binding material. Reclaims of moulding sands with binders of the form of resin were assessed

with regard to ignition loss values and pH reaction, while reclaims of moulding sands with bentonite with regard to the

residual clay content and pH value. In all cases the results of the performed sieve analyses were estimated and the average

characteristic diameter dl was determined. The reclaimed matrix was applied as a full substitute of the fresh high-silica sand in typical

procedures of preparing core sands used for making shaped samples for bending strength investigations, Rg

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.

The aim of the hereby paper is to present the developed model of determining the volume and surface porosity based on the main fraction

of polifractional materials, its experimental verification and utilisation for the interpretation of effects accompanying the formation of a

moulding sand apparent density, porosity and permeability in the blowing processes of the core and moulds technology.

It was found that the addition of carbon fibers (CFs) does not affect the crosslinking process in the microwave radiation (800 W, 2.45

GHz) of the BioCo2 binder, which is a water solution of poly(acrylic acid) and dextrin (PAA/D). It has influence on BioCo2 thermal

properties. The CFs addition improves the thermostability of a binder and leads to the reduction of gas products quantity generated in the

temperature range of 300-1100°C (TG-DTG, Py-GC/MS). Moreover, it causes the emission of harmful decomposition products such as

benzene, toluene, xylene and styrene to be registered in a higher temperatures (above 700°C). BioCo2 binder without CFs addition is

characterized by the emission of these substances in the lower temperature range. This indicates the positive effect of carbon fibers

presence on the amount of released harmful products.

The selected technological tests (permeability, friability, bending strength, tensile strength) have shown that the moulding sand with the

0.3 parts by weight carbon fibers addition displays the worst properties. The addition of 0.1 parts by weight of CFs is sufficient to obtain a

beneficial effect on the analyzed moulding sands properties. The reduction of harmful substances at the higher temperatures can also be

observed.

The paper presents the results of laboratory tests into the effects of moisture and the content of two types of bentonite on dielectric properties of moulding sand. The use of electromagnetic waves in foundry industry is becoming more and more popular, which provides to some extent alternatives to conventional drying methods. Experimental studies published so far have shown the validity of using microwaves for drying classic moulding sands with bentonite. However, these studies lack data on the effect of moisture or bentonite content in moulding sand on the real component ε' or imaginary component ε'' of the relative complex electrical permittivity. The presented results may become in the future the basis for the evaluation of the composition of moulding sands, taking into account the phenomena occurring under the influence of electromagnetic field, which directly translates into the quality of the castings made and may constitute an attempt to develop a mathematical model of electric properties of moulding sands.

A thermo-insulating moulding sand with a binder made of aluminosilicate microspheres with organic binder was subjected to testing. The aim of the analysis was to determine selected technological properties of the developed compounds. Compressive strength, friability and gas permeability were determined. The binder content was changed within a range of 5÷20 wt% with a 5% step. The applied matrix is characterized by good thermo-insulating properties and a small size of grains, while synthetic organic binder has favourable functional properties, among which the most noteworthy are the extended life and setting time, good rheological properties as well as high resistance to chemical agents. The intended use of the compound is the casting of 3D CRS (Composite Reinforced Skeletons), which are characterized by a well-developed heat transfer surface area, good absorption of impact energy, low mass and a target thickness of connectors within a range of 1.5÷3 mm. The construction of 3D CRS castings is an original concept developed by the employees of the Department of Foundry Engineering at the Silesian University of Technology.

The paper presents the results of an investigation of the gases emission of moulding sands with an inorganic (geopolymer) binder with a relaxation additive, whose main task is to reduce the final (residual) strength and improves knocking-out properties of moulding sand. The moulding sand without a relaxation additive was the reference point. The research was carried out using in accordance with the procedure developed at the Faculty of Foundry Engineering of AGH - University of Science and Technology, on the patented stand for determining gas emissions. Quantification of BTEX compounds was performed involving gas chromatography method (GC).The study showed that the introduction of relaxation additive has no negative impact on gas emissions - both in terms of the total amount of gases generated, as well as emissions of BTEX compounds. Among the BTEX compounds, only benzene is emitted from the tested moulding sands. Its emission is associated with the introduction a small amount of an organic hardener from the group of esters.

The analysis of after reclamation dusts generated during the reclamation treatment of test portions of two kinds of polydispersive material in the Regmas device, is presented in the hereby paper. For the comparative purpose the fresh moulding sand marked as quartz sand „Sibelco” –1K 0.40/0.32/0.20, J88, >14000C, WK = 1.20 (acc. PN-83/H-11077), as well as the spent moulding sand, which was previously subjected to the primary reclamation and to dedusting, were used. Conditions of the process treatment were forced by the frequency of supplying the vibratory drive motors being successively 40, 50 and 60Hz for 5, 10 and 15 min. and by causing a diversified material flow through the functional system of the device (charging hopper, abrasive chamber acting as a buffer space). Two states of the process treatment, when a material was flowing through the chamber, were applied. In the first one, an intergranular surface abrasion of grains occurred as a result of the granular material circulation in the chamber forced by the vibratory drive. In the second one, the forced material flow was performed in the presence of crushing elements (steel balls), additionally introduced into the abrasive chamber. Analyses of the device influence were performed by determinations of the amount of dusts separated in the pneumatic classifier and analysis of their grain sizes by means of Analysette 22NanoTec.

Bentonites and clays are included in the group of drilling fluids materials. The raw materials are mainly clay minerals, which are divided into several groups, like montmorillonite, kaolinite, illite, biotite, muscovite, nontronite, anorthoclase, microcline, sanidine or rutile, differing in chemical composition and crystal lattice structure. Clay minerals have a layered structure forming sheet units. The layers merge into sheets that build up to form the structure of the mineral.

The aim of the studies carried out in the ŁUKASIEWICZ Research Network - Foundry Research Institute is to explore the possibility of using minerals coming from Polish deposits.

The article outlines the basic properties of hybrid bentonites, which are a mixture of bentonite clay called beidellite, originating from overburden deposits of the Turoszów Mine, and foundry bentonite from one of the Slovak deposits. As part of the physico-chemical tests of minerals, measurements included in the PN-85/H-11003 standard, i.e. montmorillonite content, water content and swelling index, were carried out. Additionally, the loss on ignition and pH chemical reaction were determined. Based on the thermal analysis of raw materials, carried out in the temperature range from 0 to 1000oC, changes occurring in these materials during heating, i.e. thermal stability in contact with liquid metal, were determined.

Examinations of the sand mixture based on pure clay and bentonite and of the sand mixture based on hybrid bentonites enabled tracing changes in permeability, compressive strength and tensile strength in the transformation zone as well as compactability referred to the clay content in sand mixture. Selected technological and strength parameters of synthetic sands are crucial for the foundry, because they significantly affect the quality of the finished casting.

Based on the analysis of the results, the optimal composition of hybrid bentonite was selected.

In this work, the influence of microwave drying parameters such as irradiation time and microwave power level on the properties of synthetic moulding sands is presented. Determination of compressive strength Rc s, shear strength Rt s and permeability Ps of synthetic moulding sands with the addition of two different bentonites, after drying process with variable microwave parameters were made. The research works were carried out using the microwave oven with regulated power range of the electromagnetic field. From the results obtained, the significant influence of both drying time and microwave power level on the selected properties of moulding sands was observed. In comparison to the conventional drying method, microwave drying allows to obtain higher compressive strength of the synthetic moulding sand. The influence of application microwave irradiation on permeability was not observed. Higher strength characteristics and shorter drying time are major advantages of application of the electromagnetic irradiation for drying of the synthetic moulding sand with regard to conventional drying method.

In the paper, an attempt is made to explain the previously observed increased effectiveness of utilising hydrated sodium water-glass grade

137 after hardening moulding sands with selected physical methods. In the modified process of preparing sandmixes, during stirring

components, water as a wetting additive was introduced to the sand-binder system. Presented are examination results of influence of faster

microwave heating and slower traditional drying of the so-prepared moulding sands on their tensile and bending strength, calculated per

weight fraction of the binder. The measurement results were confronted with SEM observations of linking bridges and with chemical

analyses of grain surfaces of high-silica base. On the grounds of comprehensive evaluation of hardened moulding sands, positive effects

were found of the applied physical process of binder dehydration and presence of the wetting additive. It was observed that introduction of

this additive during stirring, before adding the binder, improves flowing the binder to the places where durable linking bridges are created.

It was also found that the applied methods of hardening by dehydration enable creation of very durable linking bridges, strongly connected

with the sand base, which results in damages of high-silica grain surfaces, when the bridges are destroyed.

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: 5000 C – 13000 C 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).

In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is

presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within

100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared

with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation

of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand

grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The

observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in

internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at

elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular

particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of

chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand

and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.

The paper presents the idea of the integrated recycling system of used moulding sands with organic resins. A combination of the method of

forecasting averaged ignition loss values of moulding sands after casting and defining the range of necessary matrix reclamation

treatments in order to obtain its full recycling constitutes the basics of this process.

The results of own investigations, allowing to combine ignition loss values of spent moulding sands after casting knocking out with

amounts of dusts generated during the mechanical reclamation treatment of such sands, were utilized in the system.