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1

Thermogravimetric analysis of modified cellulose mixtures in air

Zawieja Z., Sawicki J.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

153--157

EN

The paper includes the TG-DTG thermogravimetric air-testing of a cellulose mixture modified with the additives of expanded vermiculite or expanded perlite. A thermal degradation test was carried out at 1000°C with a simultaneous qualitative analysis of the emitted gases. During the thermal degradation process, the thermal effects were also measured. The research results indicate that expanded vermiculite or expanded perlite do not emit toxic gases during thermal degradation. The cellulose mixture modification, with the additives of expanded vermiculite or perlite, does not result in the creation of new gaseous compounds in the process of thermal degradation. As investigated below, the mixtures tested in this article find application in gating systems for supplying liquid metal in no-bake moulds. Such cellulose-based material solutions shall allow the foundry industry to introduce less gas vaporising technologies within the entire casting production process.

2

Qualitative analyses of gas evolution from modified cellulose mixtures during thermal degradation IN AIR AND ARGON

Zawieja Z., Sawicki J.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 3

24--30

EN

This paper presents the application of mineral additives, such as expanded perlite, expanded vermiculite and microspheres in items used in founding. Mixed with paper pulp and aluminosilicate resin as a binder, these additives are the base of a mixture patented by the authors, which can be used in the production of pipe shapes and connectors with a circular cross-section in casting systems in the founding industry. These mixtures were subjected to TG thermal degradation during which a quantitative analysis of the emitted fumes was carried out. The analysis did not detect any other compounds than those formed by the combustion of cellulose materials, which indicated that no chemical reaction took place between the applied additives and cellulose at high temperatures.

3

Gas Evolution Quantitative Analysis at a Temperature of 900°C of a Cellulose Mixture Modified by Mineral Additives

Zawieja Z., Sawicki J.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2B

1051--1055

EN

This article presents a gas evolution study of a novel, cellulose-based mixture with such mineral additives as expanded perlite, expanded vermiculite and microspheres. Inorganic alumina-silica binder was used to produce an uniform, bound mixture. The results have shown that the novel, cellulose-based mixture, obtained from waste paper, with mineral additives, emits smaller amounts of gas, while retaining the same thermal resistance.

4

Odporność termiczna mieszanki celulozowej modyfikowanej proekologicznymi dodatkami mineralnymi przeznaczonych na kształtki odlewnicze

Zawieja Z., Sawicki J.

Inżynieria Materiałowa

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2015

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Vol. 36, nr 6

543--547

PL

Istniejące obecnie na rynku komercyjne mieszanki celulozowe zawierają w sobie toksyczne oraz szkodliwe lepiszcza organiczne będące źródłem bardzo silnych efektów gazotwórczych przy kontakcie z ciekłym metalem, co ma kluczowy wpływ na proces zalewania ciekłym metalem oraz na jakość finalnego produktu, jakim jest odlew. Jako alternatywę autorzy zaproponowali kształtki wykonane z mieszanki celulozowej wzbogaconej w dodatki mineralne proekologiczne, jak perlit ekspandowany oraz wermikulit ekspandowany, a także mikrosfery. W pracy przedstawiono wyniki badań nad właściwościami termicznymi zmodyfikowanej mieszanki celulozowej, z której są wykonywane degradowalne kształtki oraz złączki cylindryczne. Przeprowadzone badania wskazują, iż materiały autorskie zgłoszone do opatentowania mają podobną odporność termiczną do obecnie dostępnych na rynku mieszanek celulozowych, na co wskazują pomiary temperatury stygnącego ciekłego metalu w osi testowanych kształtek wykonanych z różnych mieszanek celulozowych. Zaobserwowano jednocześnie, iż pojawia się efekt egzotermiczny w trakcie stygnięcia ciekłego metalu wydłużający proces krystalizacji w mieszankach zawierających w swym składzie aluminio-silikaty. Uzyskane wyniki badań wykazały, iż opatentowana mieszanka na bazie pulpy papierowej może być z powodzeniem stosowana jako alternatywny materiał wykorzystywany na elementy układów wlewowych do jednorazowych form piaskowych.

EN

Commercially available cellulose mixtures are consisting harmful and toxic binders resulting very high gas emission effects during liquid metal pouring process therefore having influence on the final casting product quality. Authors proposed the opposing alternative solution for fittings made of cellulose mixture modified by mineral ecological additives such an expanded perlite, expanded vermiculite and microspheres. The results on thermal properties of the modified cellulose mixture used for fittings and cylindrical shapes manufacturing are presented in the following article. Conducted examination are showing the authors materials requested to be patented are having similar thermal resistance to commercially already available cellulose samples which is visible on measurements of the liquid metal cooling process inside tested pipes made from different cellulose mixtures. Additionally exothermic effect is appearing during cooling process resulting liquid metal crystallization extension process visible in the samples consisting aluminiosilicates. Received result from investigations are showing the patented mixture based on paper pulp can be used as alternative material used for gating system fittings in the disposable sand moulds.

5

Gas Emissivity of a Modified Cellulose Mix at the Temperature of 900°C

Zawieja Z., Sawicki J.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 3

91--94

EN

This paper presents the findings of a study of gas emissivity and the volumetric gas flow rate from a patented modified cellulose mix used in production of disposable sand casting moulds. The modified cellulose mix with such additives as expanded perlite, expanded vermiculite and microspheres was used as the study material. The results for gas emissivity and the gas flow rate for the modified cellulose mix were compared with the gas emissivity of the commercial material used in gating systems in disposable sand casting moulds. The results have shown that the modified cellulose mix is characterized by a lower gas emissivity by as much as 50% and lower gas flow rate per unit mass during the process of thermal degradation at the temperature of 900°C, compared to the commercial mix. It was also noted that the amount of microspheres considerably affected the amount of gas produced.

6

Expanded perlite, expanded vermiculite and microspheres as fillers in new generation paper pulp mixtures used for contact with liquid metal

Zawieja Z., Sawicki J.

Advances in Science and Technology. Research Journal

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2015

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Vol. 9, nr 26

83--88

EN

Liquid metal when filling sand casting mould while pouring it out from ladle at the first moment comes across the sprue/gate system of the mould the purpose of which is to transfer liquid metal and feed the mould recess. The materials presently used for the elements of the sprue/gate systems are based on ceramics or the mixtures based on paper pulp. In this study the use of alternative mineral additions such as expanded perlite, expanded vermiculite, and microspheres as the fillers to paper pulp acquired from waste-paper for the use for the elements of mould sprue/gate systems or also other applications for the contact with liquid metal are presented. Experimental mould tube shapes made on the basis of the paper pulp based mixture patented by the authors were poured over with liquid metal. For the comparison, ceramic shapes and commercially available cellulose shapes were investigated in the same way. In order to compare the crystallization processes, a measurement of the cooling off liquid metal was carried out for all the analysed tube samples. From the so obtained metal samples metallographic microsections were made to compare cast iron microstructures. The results obtained from the investigations carried out have shown that the patented paper pulp based mixture may well be applied as an alternative material used for the elements of the sprue/gate systems for disposable sand moulds.

7

Analiza porównawcza kształtek ceramicznych z celulozowymi wykorzystywanych do tworzenia układów wlewowych w odlewnictwie

Zawieja Z., Sawicki J., Gumienny G.

Inżynieria Materiałowa

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2014

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Vol. 35, nr 5

434--437

PL

Rodzaj materiału z jakiego wykonuje się kształtki do tworzenia układów wlewowych ma kluczowy wpływ na proces zalewania ciekłym metalem oraz na jakość finalnego produktu jakim jest odlew. W pracy przedstawiono wyniki badań dotyczące wpływu materiału kształtki stosowanej do układów wlewowych na gradient temperatury ciekłego żeliwa oraz mikrostrukturę odlewu. Do badań wykorzystano cylindryczne kształtki wykonane z klasycznej masy ceramicznej oraz z tworzywa na bazie masy celulozowej. Ustalono, iż kształtki z masy celulozowej wytwarzają silny efekt egzotermiczny po ok. 150 sekundach od momentu zalania ciekłym żeliwem. Wynikiem efektu egzotermicznego z zastosowaniem kształtki celulozowej jest dłuższy czas istnienia żeliwa w stanie ciekłym, co opóźnia inicjację krystalizacji eutektyki w porównaniu z kształtką ceramiczną. Wydłużenie przemiany eutektycznej w przypadku zastosowania kształtek celulozowych prowadzi to stabilniejszego procesu krystalizacji, w wyniku czego dominuje równowagowa mikrostruktura perlityczna z wydzieleniami grafitu oraz węglików, a zastosowanie kształtki ceramicznej prowadzi do tworzenia mikrostruktury ausferrytu również z wydzieleniami grafitu oraz węglików.

EN

Liquid metal casting process and the final casting product quality is highly depending on the kind of material used for tube fittings manufacturing in order to create the feeding channels. The following study presents the influence of type of the material used for feeding channels on the temperature gradient of the liquid iron as well on the microstructure of the iron casting. Ceramic classic and cellulose based fittings both cylindrical tube shaped have been used for the investigation. 150 seconds after pouring liquid iron the cellulose based tube fittings are generating very high exothermic effect. Compared to the ceramic fitting the cellulose tube, due to such an exothermic phenomena, keeps the iron as a liquid in longer period and it is providing consequently later the eutectic crystallization. Longer eutectic crystallization reaction leads to more steady process therefore perlit equilibrium phase including graphite and carbides microstructure is dominating when cellulose based fitting are in use. Ausferrite including graphite and carbides is more observed when ceramic tube fittings for iron processing are taken.

8

Investigation of an Advanced Cellulose Profile Used for the Manufacture of Gating Systems

Zawieja Z., Sawicki J., Gumienny G., Sobczyk-Guzenda A.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 3

123--128

EN

The here in paper contains the results of investigations on a new type of cellulose blend used for the manufacture of profiles applied in the process of making gating systems in the foundry industry. A standard cellulose profile was subjected to an experiment. During the experiment the profile was filled with a liquid cast iron and at the same time the temperatures of the liquid metal crystallizing inside the profile were measured as well as the temperature of the outer layer of the profile was controlled. Further, the microstructure of the cast iron, which crystallized out inside the cellulose profile, was analysed and the cellulose, thermally degraded after the experiment, was verified with the use of the chemical analysis method. Moreover, a quality analysis of the original as well as the degraded cellulose profile was run with the use of the FTIR infrared spectroscopy. The presented results revealed that the cellulose blend is aluminium silicate enriched and contains organic binder additives. The cast iron, which crystallized out, tended to have an equilibrium pearlitic structure with the release of graphite and carbides. The generation of disequilibrium ausferrite phases was also observed in the structure.