View metadata, citation and similar papers at core.ac.uk brought to you by CORE ISSN 0543-5846 M. HOLTZER, A. BOBROWSKI, R. DAŃKO, A. KMITA, S. ŻYMANKOWSKA-KUMON, provided by Directory of Open Access Journals M. KUBECKI, M. GÓRNY METABK 53(4) 451-454 (2014) UDC – UDK 621.746:621.74.04:668.44=111 EMISSION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) AND BENZENE, TOLUENE, ETHYLBENZENE AND XYLENE (BTEX) FROM THE FURAN MOULDING SANDS WITH ADDITION OF THE RECLAIM Received – Primljeno: 2014-02-12 Accepted – Prihvaćeno: 2014-05-30 Original Scientific Paper – Izvorni znanstveni rad In this paper, the results of decomposition of a moulding sand with furfuryl resin also on a quartz matrix and with additions of a reclaimed material, under industrial conditions, are presented. Investigations of the gases emission in the test foundry plant were performed according to the original method developed in the Faculty of Foundry Engi- neering, AGH UST. The dependence of the emitted PAHs and BTEX group substances and ignition losses on the re- claim fraction in a moulding sand are of a linear character of a very high correlation coefficient R2. On the bases of the derived equations, it is possible to determine the amount of the emitted hazardous substances from the mould- ing sand containing the known fraction of the reclaim. Key words: foundry, moulding sands, BTEX, PAHs, reclaim INTRODUCTION BTEX and PAHs group increases. The results of labora- tory examinations of thermal decompositions of a Application of synthetic resins as binding agents for moulding sand with furfuryl resin on a quartz matrix, moulding and core sands constitutes a threat for the with various additions of the reclaimed material, were natural and work environment. This is caused by gener- presented in paper [13]. Whereas in this paper, the re- ating, under an influence of high temperatures of liquid sults of decomposition of a moulding sand with furfuryl metal, highly toxic substances. Depending on the kind resin also on a quartz matrix and with additions of a re- of resin applied - under an influence of temperatures - claimed material, but under industrial conditions, are such substances as: furfuryl alcohol, formaldehyde, presented. phenol, compounds from the BTEX and PAHs groups, The obtained results allow to determine the maxi- can be formed and released. These compounds are re- mum amount of reclaim added to the molding that gives leased into the atmosphere when a mould is poured with no consequences of deterioration of the working and liquid metal, during a mould cooling, and when castings environmental conditions. are knocked out. or eluted during storing of spent found- ry sands [1-11]. The results of investigations of thermal decomposi- METERIALS AND TESTING tions of moulding sands prepared with various kinds of METHODO-LOGY OF INVESTIGATIONS furan resins, in which fresh sand was a matrix, are given Moulding sands with urea-formaldehyde resin (1 %) in the paper [12]. Presently nearly each foundry plant, modified by furfuryl alcohol (content of a furfuryl alco- which is using moulding sands with furfuryl resins, ap- hol is about 80 %), hardened by mixture (0,5 %) of sul- plies as a matrix the reclaimed material. A reclaim orig- fonic acid and inorganic acid were used in tests. Mould- inated from the mechanical reclamation always contains ing sands were preparing from fresh quartz sand and certain amounts of organic substances, either as binder reclaim. left overs (not removed in the reclamation process) or Moulding sands of the following composition were organic substances condensed on quartz grains. When a tested: SP100 – matrix 100 % fresh quartz sand; R50P50 liquid metal influences moulding sands prepared with – matrix 50% fresh quartz sand and 50 % reclaim; R100 reclaim additions, the emission of substances from the – matrix 100 % reclaim. Investigations of the gases emission in the test foun- M. Holtzer, A. Bobrowski, R. Dańko, A. Kmita, S. Żymankowska- dry plant were performed according to the original Kumon, M. Górny – AGH-University of Science and Technology, Fac- method developed in the Faculty of Foundry Engineer- ulty of Foundry Engineering, Krakow, Poland M. Kubecki, Institute for Ferrous Metallurgy in Gliwice, Poland ing, AGH UST. METALURGIJA 53 (2014) 4, 451-454 451 M. HOLTZER et al.: EMISSION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) AND BENZENE, TOLUENE... A sample of the investigated moulding sand of a cyl- 0,28 inder shape of dimensions Φ 50 x 50 mm, weight about 150 g, was poured with liquid cast iron of a temperature 0,21 of 1 350 oC. The liquid metal mass was 9 kg. Gases SP100 emitting from the sample, after pouring it with liquid R50P50 R100 /gs 0,14 metal are adsorbed on active carbon (during the BTEX 3 measurement) or polyurethane foam (during the PAHs cm measurement). The whole mould (weight 24 kg) is made 0,07 of green sand. The analysis of substances from BTEX group were Velocity of gases emission / 0 carried out by the gas chromatography method with the 0 100 200 300 application of the flame-ionising detector (FID). The Time / s identification of PAHs was carried out by means of the system consisting of the gas chromatograph Trace GC Figure 2 Velocity of gases emission, from the investigated Ultra. The device HPLC Dionex 3 000 with fluorescent moulding sands after pouring the mould with cast iron of a temperature of 1 350 oC detection was used for the liquid chromatography. At the determination of compounds from the PAHs Table 1 Results of the BTEX content emitted from the group a part of hydrocarbons was condensing on the moulding sands during the thermal decomposition formed dust particles and together with them was de- Sample BTEX content in emitted gases posited on the filter placed in the capsule before the mg/kg moulding sand polyurethane foam. Therefore at determining the total BTEX amount of generated PAHs the polyurethane foam as SP 100 333,137 2,826 0,621 0 ± 33,31 ± 0,28 ± 0,06 well as the dust on the filter were analysed. R50P50 512,516 18,148 00 ± 51,25 ± 1,81 R100 956,602 91,144 1,184 7,723 RESULTS AND DISCUSSION ± 95,66 ± 9,11 ± 0,11 ± 0,77 B-Benzene, T-Toluene, E-Ethylbenzene, X- Xylen Measurement of emitting gases amounts The diagram showing the amount of generated gases the matrix is completely substituted by the reclaim. Along with respect to time is presented in Figure 1, while the rate with an increasing volume of emitted gases, at the in- of their evolution in Figure 2. creasing fraction of the reclaim, the increased benzene concentration is visible (from 333 mg/kg - for the fresh Measuring the content of components sand matrix, to 950 mg/kg - for the reclaim matrix only). from the btex group Quantitative data of the emissivity of components Determination of the PAHs group from the BTEX group are listed in Table 1. substances An addition of the reclaim to the moulding sand ma- Analytical results of the content of substance from trix causes a distinct increase of the emitted gases vol- the PAHs group in gases emitted during moulds pouring ume. Two maxima of emission rates were seen in the are listed in Table 2. curves describing the kinetics of gases emissions. The gases emission rate nearly doubles when the fresh sand in Table 2 Analytical results of the total PAHs content, emitted from moulding sands deposited on the filter together with dusts as well as on the 25 polyurethane foam R100 Sample Foam Filter TOTAL /g 20 3 R50P50 µg/kg moulding sand 15 SP100 3 421 ± 684 4 537 ± 907 7 958 ± 1592 SP100 R50P50 5 386 ± 1077 7 920 ± 1584 13 306 ± 2661 10 R100 13 251 ± 2650 1 733 ± 347 14 983 ± 2997 5 In practice only nafthalene, which has the lowest Gases volume / cm 0 boiling point (218 oC) and simultaneously the highest 0 100 200 300 400 500 600 700 800 900 vapour pressure out of the tested PAHs, was adsorbed Time / s on the polyuretane foam. The content of the remaining PAHs adsorbed on the foam is minimal. In case of the Figure 1 Emissivity of gases in time, from the investigated moulding sands after pouring the mould with cast moulding sand R100 additionally fluorene, phenan- iron of a temperature of 1 350 oC threne and fluoranthene i.e. substances which boiling 452 METALURGIJA 53 (2014) 4, 451-454 M. HOLTZER et al.: EMISSION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) AND BENZENE, TOLUENE... ¤ ¤ª ¤ ¡ê£ªªê svp svp £¥ êÓꪱª¢£êÐꡱ£¥££ êÓꪱª¢£êÐꡱ£¥££ ¡ê¡ªªê yüêÓꪱ©¨¤¥ £ £ª yüêÓꪱ©¨¤¥ £ ©ªªê ¢¥ ¢ §ªªê ¢ª ¢ ê ilulul ê ¡¥ ¥ªªê ∑PAHs (foam+filter) êÓꦱ¢£¤§êÐꢨ©±ª¢ ¡ ¡ª ¡ sêêê½êÜ £ªªê yüêÓꪱ©¤££ sêêê½êÜ êÓꪱª§ª¢êÐꨱ¥¦©¨ ¥ yüêÓꪱ©¡¦¦ ¡ªªê ª ª ª jê½ê½êê ª¥ª¡ªªjê½ê½êê ª ¥ª ¡ªª mêêêêêêê½êÜ mêêêêêêê½êÜ Figure 3 Dependence of the emission of benzene and loss on Figure 4 Dependence of the generated PAHs substances ignition on the reclaim fraction in the moulding (total emission was taken into account, i.e. sands matrices. substances found on the filter and polyuretane foam) and loss on ignition on the reclaim fraction in points do not exceed 400 oC, are adsorbed on the foam the moulding sands matrices. in higher amounts. The amount of the PAHs adsorbed on the filter, for this moulding sand, constitutes only sand loss on ignition are of a similar pathways, it is also approximately 10 % of all substances emitted from this possible to estimate the amount of these generated sub- group. In case of two remaining moulding sands (SP100 stances on the basis of this parameter. and R50P50) approximately 40 % of the determined PAHs was collected on the foam and 60 % on the filter.