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Gas Evolution of GEOPOL® W Sand Mixture and Comparison with Organic Binders

Vykoukal M., Burian A., Přerovská M., Bajer T., Beňo J.

Archives of Foundry Engineering

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2019

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iss. 2

49--54

EN

The article deals with the gas development of the geopolymer binder system hardened by heat and provides the comparison with organic binder systems. The GEOPOL® W technology is completely inorganic binder system, based on water. This fact allow that the gas generated during pouring is based on water vapour only. No dangerous emissions, fumes or unpleasant odours are developed. The calculated amount of water vapour generated from GEOPOL® W sand mixture is 1.9 cm3/g. The measured volume of gas for GEOPOL® W is 4.3 cm3/g. The measurement of gas evolution proves that the inorganic binder system GEOPOL® W generates very low volume of gas (water vapour) in comparison with PUR cold box amine and Croning. The amount of gas is several times lower than PUR cold box amine (3.7x) and Croning (4.2x). The experiment results are consistent with the literature sources. The difference between the calculated and the measured gas volume is justified by the reverse moisture absorption from the air after dehydration during storing and preparing the sand samples. Minimal generated volumes of gas/water vapour brings, mainly as was stated no dangerous emissions, also the following advantages: minimal risk of bubble defects creation, the good castings without defects, reduced costs for exhaust air treatment, no condensates on dies, reduced costs for cleaning.

2

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.

3

Studies of gas atmosphere near the metal-mould interface during casting and solidification of ductile iron

Mocek J., Chojecki A.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 4

166-170

EN

In sand moulds, at a distance of 3 mm from the metal-mould interface, the sensors of temperature, and of oxygen and hydrogen content were installed. Temperature and the evolution of partial gas pressure have been analysed in moulds bonded with bentonite with or without the addition of seacoal, water glass or furan resin. Moulds were poured with ductile iron. For comparison, also tests with the grey iron have been executed. It was found that the gas atmosphere near the interface depends mainly on the content of a carbonaceous substance in the mould. In the green sand moulds with 5% of seacoal or bonded with furan resin, after the mould filling, a sudden increase in the hydrogen content and the drop of oxygen is observed. This gas evolution results from the oxidation of carbon and reduction of water vapour in the mould material, and also from the reduction of water vapour and alloy reoxidation. In carbon-free sand, the evolution in the gas composition is slower because water vapour is reduced only at the interface. Changes of oxygen and hydrogen content in the controlled zone are determined by the transport phenomena.

4

Badania jakości regeneratu ze zużytych mas ze spoiwem organicznym

Dańko R.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 1s

21--26

PL

W publikacji przedstawiono uzupełniające metody badań oraz aparaturę do oceny jakości regeneratu i tych właściwości mas formierskich ze spoiwami utwardzanymi chemicznie, przygotowywanych z regeneratem, które są istotne dla kompleksowej oceny procesu recyklingu osnowy. Nowoczesne systemy oceny mas formierskich wymagają bardziej wnikliwego podejścia do czynników decydujących zarówno o ich przydatności technologicznej jak również o wpływie na otaczające środowisko naturalne. W tym kontekście pełna ocena jakości zregenerowanej osnowy wykracza poza zwyczajowo stosowane metody instrumentalne i wymaga ich uzupełnienia o bardziej zaawansowane aparaturowo metody badawcze. Pozwala to szerzej spojrzeć na ocenę zregenerowanej osnowy, zarówno w aspekcie jej użycia do sporządzania mas formierskich, jako substytutu świeżego piasku, ale także pod kątem ochrony środowiska. Do takich nowoczesnych metod można zaliczyć między innymi analizę ziarnową regeneratu za pomocą dyfrakcji laserowej, a także ocenę gazotwórczości masy formierskiej oraz identyfikację rodzaju emitowanych gazów i zawartości w nich gazów z grupy BTEX, które są szczególnie niebezpieczne z punktu widzenia BHP.

EN

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.

5

Assessment of environmental influence of bentonite and lustrous carbon carrier - in an aspect of gases emission

Bobrowski A., Holtzer M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 1

21-24

EN

The emission results of the selected gases from a bentonite-carbon mixture and from dusts originated from dry de-dusting of the green sand processing plant (at high temperatures) are presented in the paper. In order to check and compare samples of dusts and bentonite-carbon mixtures in respect of emission of gases the Evolved Gas Analysis (EGA) was performed by means of the mass spectrometry method. This method allows to determine emission conditions of the selected chemical compounds.