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Effect of Reclaim Addition on the Mechanical and Technological Properties of Moulding Sands Based on Pro-Ecological Furfuryl Resin

Kamińska J., Puzio S., Angrecki M., Łoś A.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 4

1425--1429

EN

Increasing demands are imposed on foundries to enforce the manufacture of castings characterized by tight dimensional tolerances, high surface finish and total absence of casting defects. To face these challenges, castings are increasingly made in loose self-hardening sands with furfuryl resin, commonly known as furan sands. In the group of self-hardening sands with synthetic resins, loose self-hardening sands with furfuryl resin enjoy the greatest popularity. The sand mixtures based on furan resins are usually subjected to mechanical reclamation. The consumption of binder and hardener and thus the cost of the sand depend on the quality of reclaim, and mainly on the dust removal degree.The planned tightening of the environmental protection regulations in the EU countries, including limiting the content of free furfuryl alcohol in resins and reducing the emission of furfuryl alcohol, formaldehyde and BTEX compounds at workplaces, necessitated the development of a new generation of eco-friendly furfuryl resins that have recently appeared on the market. The main aim of this article was to determine the effect of reclaim content on the sand parameters, such as bending strength, tensile strength, bench life, gas-forming tendency and loss on ignition. Tests were carried out with reclaim content in the sand mixture varying from 50 to 90%. The reclaim obtained by dry mechanical reclamation was supplied by one of the domestic foundries. The results showed that the highest mechanical properties were obtained in sands containing 60% of the reclaim.

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Preliminary Tests of Innovative Eco-Friendly Furfuryl Resins and Foundry Sand Mixtures Based on These Resins

Kamińska Jadwiga, Puzio Sabina, Angrecki Michał, Stachowicz Mateusz, Łoś Anna

Journal of Ecological Engineering

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2019

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Vol. 20, nr 9

285--292

EN

The foundry industry in Poland and EU member states is growing steadily. The alloys based on ferrous metals (cast steel and cast iron) largely contribute to this upward trend. Currently, foundries are facing the problem of increasing requirements, which enforce the production of castings characterized by high dimensional accuracy and surface smoothness with parallel elimination of casting defects. Castings are mostly made in moulding sand mixtures, which are also subject to more and more stringent requirements to meet the above-mentioned casting acceptance conditions. Additionally, moulding sands should ensure adequate mould stiffness to avoid the risk of dimensional deformations during the pouring of liquid metal to this mould and casting solidification. For these reasons, the production of this type of castings has been dominated by loose self-hardening sands with furfuryl resin, commonly called furan sands. In the group of self-hardening sands with synthetic resins, loose self-hardening sands with furfuryl resin enjoy the greatest popularity. What accounts for this fact is the high level of the reclamability of these sands, the possibility of obtaining castings with high dimensional accuracy, the ability to make intricate moulds and cores, the binding process taking place at ambient temperature, and low content of binder. Unfortunately, this technology also has some disadvantages, which include short lifetime of the sand mixture, harmful gases emitted from the sand, and currently also high cost of the sand mixture. The anticipated tightening of the environmental protection regulations in the EU countries, including limiting the content of free furfuryl alcohol in resins (<25% by mass) and reducing the emission of furfuryl alcohol, formaldehyde and BTEX compounds at workplaces, necessitated the development of a new generation of furfuryl resins friendly to the environment. The article compares the results of testing the strength properties of foundry moulding sands using two types of resins, i.e. the resin of a new generation synthesized by Grupa Azoty JRCh and a commercial resin used in the foundry industry. Additionally, derivatographic studies of the above mentioned sand mixtures were conducted, and the loss on ignition and the amount of gases emitted by the sand mixture were determined. Melting was also carried out to study the impact of the resin used on the surface quality of iron castings.

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Effect of Mechanical Reclamation Cycle on Strength Parameters of Loose Self-Hardening Sands Based on Furfuryl Resin

Kamińska J., Basińska E., Angrecki M., Palma A.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1843--1846

EN

The results of mechanical reclamation of waste moulding sands with furfuryl resin and activators of new generation are presented. The aim of the research described in this study was to determine what effect the addition of reclaim obtained in the process of dry mechanical reclamation could have on the properties of furan sands. The sand supplied by one of the domestic foundries was after the initial reclamation subjected to a two-step proper reclamation process. The following tests were carried out on the obtained reclaim: pH, S and N content, loss on ignition and comprehensive sieve analysis. The obtained reclaim was next used as a component of moulding sands with furfuryl resin, wherein it formed 50% and 80% of the base moulding material, respectively. The strength properties of the ready sand mixtures (bending strength Rgu and tensile strength Rm u ) were determined after the hardening time of 0.5, 1, 2, 4 and 24 hours.

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Porównanie parametrów procesu granulacji pyłów odpadowych z procesu regeneracji

Kamińska J.

Prace Instytutu Odlewnictwa

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2015

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T. 55, nr 4

51--58

PL

W artykule przedstawiono wyniki badań procesu bezciśnieniowej granulacji odlewniczych pyłów generowanych podczas: regeneracji mechanicznej zużytej masy z bentonitem (Pył 1), suchej regeneracji mechanicznej mieszaniny mas zużytych składających się w około 90% z masy formierskiej z technologii Floster S oraz 10% z masy rdzeniowej z żywicą fenolową typu rezolowego (Pył 2) oraz pyłów generowanych w procesie suchej regeneracji mechanicznej mas zużytych, których spoiwem są żywice furanowe (Pył 3). Badania miały na celu wytworzenie granulatu o określonych parametrach wymiarowych i wytrzymałościowych. Granule tworzono z czystego pyłu bentonitowego oraz z mieszanin o następujących składach: 75% wag. pyłów uzyskanych po regeneracji mieszaniny mas z 25% wag. pyłów z masy z bentonitem oraz 50% wag. pyłów uzyskanych po regeneracji masy furanowej i 50% wag. pyłów z masy z bentonitem. Nawilżony pył z masy bentonitowej został użyty jako spoiwo umożliwiające granulowanie się pyłów poregeneracyjnych z technologii sypkich mas samoutwardzalnych. Wyznaczono następujące parametry gotowego produktu finalnego: zawartość wilgoci (W), wytrzymałość zrzutową granulek (Wz), badaną bezpośrednio po procesie granulacji oraz po 1, 3, 5, 10 i 30 dobach sezonowania oraz wodoodporność granulek po 24 h zanurzenia w wodzie. Badania przeprowadzono dla granulatów uzyskanych przy nachyleniu misy granulatora wynoszącego 45° oraz dla czterech prędkości obrotowych misy wynoszących: 10, 15, 20 i 25 obr/min.

EN

The results of studies of the process of pressure-free granulation of foundry dust were described, including dust generated in the mechanical reclamation of waste bentonite sand (Dust 1), dust generated in the dry mechanical reclamation of waste sand mixture containing approximately 90% of Floster S moulding sand and 10% of core sand with a resol type phenolic resin (Dust 2), and dust generated in the dry mechanical reclamation of waste furan resin-bonded sand (Dust 3). The aim of the studies was to produce granules of specified dimensions and strength parameters. Dust granules were formed from pure bentonite dust and two dust mixtures of the following compositions: mixture 1 – 75 wt. % of dust from the reclamation of various mixed foundry sands and 25 wt. % of dust from the reclamation of bentonite sand, and mixture 2 – 50 wt. % of dust from the reclamation of furan sand mixed with 50 wt. % of dust from the bentonite sand. The moistened bentonite sand dust was used as a binder in the granulation of post-reclamation dust from the technology of loose self-hardening sands. The following parameters of the final product were determined: final moisture content (W), the shattered resistance of granules (Wz) tested immediately after the granulation process and after the lapse of 1, 3, 5, 10 and 30 days of seasoning, and water resistance of granules after the immersion in water for 24 hours. Studies were conducted on granules produced in the granulator pan inclined at an angle of 45° and rotating at four different speeds of 10, 15, 20 and 25 rev/min.

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Prediction of Properties of Microwave-Hardened Sandmixes Containing Water-Glass with Use of Neural Networks

Stachowicz M., Pałyga Ł., Granat K.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 2

99--104

EN

Presented are results of a research on the possibility of using artificial neural networks for forecasting mechanical and technological parameters of moulding sands containing water-glass, hardened in the innovative microwave heating process. Trial predictions were confronted with experimental results of examining sandmixes prepared on the base of high-silica sand, containing various grades of sodium water-glass and additions of a wetting agent. It was found on the grounds of obtained values of tensile strength and permeability that, with use of artificial neural networks, it is possible complex forecasting mechanical and technological properties of these materials after microwave heating and the obtained data will be used in further research works on application of modern analytic methods for designing production technology of high-quality casting cores and moulds.

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Granulation of after reclamation dusts from the mixed sands technology: water glass – resolit

Kamińska J., Dańko J.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 2

65--70

EN

A technology of sands with water glass hardened by liquid esters is a cheap and ecologic method of producing moulding sands. Due to these advantages, this technology is still very important in several foundry plants for production of heavy iron and steel castings. Reclamation of the mixed moulding and core sands generates significant amounts of dusts, which require further treatments for their reuse. The results of investigations of a pressureless granulation of dusts generated in the dry mechanical reclamation process of the mixture consisting in app. 90% of moulding sands from the Floster S technology and in 10% of core sands with phenolic resin resol type, are presented in the hereby paper. Investigations were aimed at obtaining granulates of the determined dimensional and strength parameters. Granules were formed from the mixture of dusts consisting of 75 mass% of dusts after the reclamation of sands mixture and of 25 mass% of dusts from bentonite sands processing plant. Wetted dusts from bentonite sands were used as a binding agent allowing the granulation of after reclamation dusts originated from the mixed sands technology.

PL

Technologia mas ze szkłem wodnym utwardzanym ciekłymi estrami jest tanią i bardzo ekologiczną metoda wytwarzania mas formierskich. Z uwagi na te zalety technologia ta ma nadal duże znaczenie w wielu odlewniach do wykonywania form dla produkcji ciężkich odlewów żeliwnych i staliwnych. Regeneracja mieszaniny masy formierskiej oraz mas rdzeniowych tworzy znaczne ilości pyłów poregeneracyjnych, które wymagają dalszej obróbki w celu ponownego ich zagospodarowania. W pracy przedstawiono wyniki badań procesu bezciśnieniowej granulacji pyłów generowanych w procesie suchej regeneracji mechanicznej mieszaniny mas zużytych składających się w około 90% z masy formierskiej z technologii Floster S oraz 10% z masy rdzeniowej z żywicą fenolową typu rezolowego. Badania miały na celu wytworzenie granulatu o określonych parametrach wymiarowych i wytrzymałościowych. Granule tworzono z mieszaniny pyłów składającej się w 75% mas. z pyłów uzyskanych po regeneracji mieszaniny mas oraz w 25% mas. z pyłów z masy z bentonitem. Nawilżony pył z masy bentonitowej został użyty jako spoiwo umożliwiające granulowanie się pyłów poregeneracyjnych z technologii mas mieszanych.