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Wpływ przygotowania próbek gruntów i metodyki oznaczania na zawartość części organicznych w gruncie

Nguyen Giang

Polish Journal of Materials and Environmental Engineering

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2023

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Vol. 6 (26)

57--65

EN

Soil organic matter content (SOM) is used e.g. in soil classification and erosion evaluation. How-ever, its value depends on soil specimen preparation and test method so it is useful to deal with these issues. Totally 150 specimens of soils CI, MS (from Bielsko-Biała, Poland) and different 3 soils, all classified as GC (from Ujsoły, Poland) were tested. To obtain values of SOM, the oxidation method using 30% hydrogen peroxide solution (H2O2) and loss of weight on ignition method (LOI) at 800°C (LOI-800) according to Polish Standard PN-88/B-04481 and LOI at 440°C according to the ASTM D 2974-87 (LOI-440) were applied. The tests were carried out for parti-cles smaller than 0.5 mm. For every soil, 30 specimens (every with a mass about 10 g of dry soil) were prepared from 2400 g of dried soil for 3 methods, so for every method, 10 specimens, taken from various soil amount in frame of total 800 g were prepared. The results showed that values of SOM of tested soils varied from 0.33% to 6.09%. The largest relative difference in values of SOM, caused by soil specimen preparation, was 97.63% (H2O2, soil GC) and the smallest relative difference was 1.65% (LOI-800, soil CI). The largest relative difference in values of SOM, caused by test method was 1126.53% (LOI-800 and H2O2, soil GC) and the smallest relative difference was 15.17% (LOI-800 and H2O2, soil CI). The various values of SOM caused by dif-ferent test method differently classify soils from organic point of view by the ISO14688-2:2004.

PL

Przeanalizowano wpływ przygotowania próbki gruntu i metody oznaczania na zawartość ma-terii organicznej (SOM). W sumie przebadano 150 próbek gruntów (przygotowanych z różnej ilości gruntu) z Bielska-Białej (CI, MS) oraz z Ujsół (GC). Aby uzyskać wartości SOM zastoso-wano metodę utleniania 30% roztworem nadtlenku wodoru (H2O2) oraz metodę straty masy przy prażeniu (LOI) w temperaturze 800°C (LOI-800) i 440°C (LOI-440). Badania przeprowa-dzono dla cząstek gruntu mniejszych niż 0,5 mm. Wartości SOM wahały się od 0,33 do 6,09%. Największa względna różnica wartości SOM spowodowana przygotowaniem próbek wyniosła 97,63% (H2O2, grunt GC), a najmniejsza 1,65% (LOI-800, grunt CI). Największa względna róż-nica wartości SOM spowodowana metodą badania wyniosła 1126,53% (LOI-800 i H2O2, grunt GC), a najmniejsza 15,17% (LOI-800 i H2O2, grunt CI). Uzyskiwane różne wartości SOM mogą skutkować odmiennym klasyfikowaniem gruntu pod kątem organicznym.

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Influence of the reclamation method of spent moulding sands on the possibility of creating favourable conditions for gases flow in a mould

Łucarz M., Drożyński D.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 1

359--364

EN

The results of investigations concerning the influence of the applied sand matrix (fresh sand, reclaim) on the properties of moulding sands used for production of large dimensional castings (ingot moulds, ladles), are presented in the hereby paper. The performed investigations were aimed at determining the influence of various reclamation methods of spent moulding sands on the quality of the obtained reclaimed material. Moulding sands were prepared on the fresh quartz matrix as well as on sand matrices obtained after various reclamation methods. The selected moulding sand parameters were tested (strength, permeability, grindability, ignition losses, pH reactions). It can be stated, on the basis of the performed investigations, that the kind of the applied moulding sand matrix is of an essential meaning from the point of view of creating conditions minimising formation of large amounts of gases and their directional migration in a casting mould.

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Conditions of Thermal Reclamation Process Realization on a Sample of Spent Moulding Sand from an Aluminum Alloy Foundry Plant

Łucarz M., Dereń M.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 2

197--201

EN

The results of investigations of thermal reclamation of spent moulding sands originating from an aluminum alloy foundry plant are presented in this paper. Spent sands were crushed by using two methods. Mechanical fragmentation of spent sand chunks was realized in the vibratory reclaimer REGMAS. The crushing process in the mechanical device was performed either with or without additional crushing-grinding elements. The reclaimed material obtained in this way was subjected to thermal reclamations at two different temperatures. It was found that a significant binder gathering on grain surfaces favors its spontaneous burning, even in the case when a temperature lower than required for the efficient thermal reclamation of furan binders is applied in the thermal reclaimer. The burning process, initiated by gas burners in the reclaimer chamber, generates favorable conditions for self-burning (at a determined amount of organic binders on grain surfaces). This process is spontaneously sustained and decreases the demand for gas. However, due to the significant amount of binder, this process is longer than in the case of reclaiming moulding sand prepared with fresh components.

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State of Spent Molding Sands in the Mold Large-Size Cast

Łucarz M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

69--74

EN

The results of investigations of spent moulding sands taken from the mould at various distances from the surface of the produced casting, are presented in the paper. The casting mould was made with an application of the cooling system of the metal core in order to increase the cooling rate of the ladle casting. As temperature measurements in the mould indicated the heat flow from the metal did not create conditions for the complete burning of a moulding sand. The analysis was performed to find out changes of spent moulding sands caused by degradation and destruction processes of organic binders. Conditions occurring in the casting mould were discussed on the bases of testing: ignition losses, dusts contents, pH reactions and the surface morphology of the moulding sand samples. Factors limiting the effective mould degassing were pointed out. Operations, possible for realisation, which can limit the reasons of a periodical occurrence of increased amounts of casting defects due to changing gas evolution rates being the result of the technological process, were also indicated.

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Analysis of Spent Moulding Sands with Binders of Various Thermal Degradations, in an Aspect of a Possibility of a Directional Mould Degassing

Łucarz M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 2

21--26

EN

The results of investigations of spent moulding sands taken from the mould in which the metal core cooling system - to increase the cooling rate of the ladle casting - was applied, are presented in the hereby paper. The changes of the spent moulding sand at the casting external side being the result of degradation and destruction processes of organic binder, were analysed in this publication. Since the reclaimed material, obtained as a result of the mechanical reclamation of spent sands of the same type, is used as a grain matrix of the moulding sand, the amount of a binder left from the previous technological cycle is essential for the sound castings production. On the bases of investigations of the thermal analysis, ignition losses, dusts contents and pH values of the samples taken from the spent sand the conditions under which the process of gases displacing in the casting mould was realised as well as factors limiting the efficient mould degassing - were considered in this study. The possible reason of a periodical occurrence of an increased number of casting defects due to changing gas volume emission, being the reason of the realised technological process, was indicated.

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Determination of Parameters of the Moulding Sand Reclamation Process, on the Thermal Analysis Bases

Łucarz M., Grabowska B., Grabowski G.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 3

1023--1027

EN

For the practical and functional reasons the investigation of the thermal decomposition process is of an essential meaning in relation to the thermal stabilisation of materials and obtaining for them the desired thermal properties. On the other side, thermal tests are carried out in order to identify degradation mechanisms, which is important in the environment protection context, including materials reuse. The cycle of investigations in which thermal TG-DTA methods were applied as supplementary ones for the works on the optimisation of the thermal reclamation process is presented in the hereby paper. The thermal reclamation process as a utilisation method of spent moulding and core sands is more costly than other reclamation methods, but in the majority of cases it simultaneously provides the best cleaning of mineral matrices from organic binders. Thus, the application of the thermal analysis methods (TG-DTA), by determining the temperature range within which a degradation followed by a destruction of bounded organic binders in moulding sands, can contribute to the optimisation of the thermal reclamation process and to the limiting its realisation costs.

PL

Ze względów praktycznych i użytkowych zbadanie procesu degradacji termicznej ma podstawowe znaczenie w odniesieniu do problemu procesu stabilizowania termicznego materiałów i otrzymywania dla nich pożądanych właściwości termicznych. Z drugiej strony badania termiczne prowadzi się w celu rozpoznania mechanizmów ich degradacji, co ma też znaczenie w kontekście ochrony środowiska, w tym ich powtórnego wykorzystania materiałowego. W publikacji przedstawiono cykl badań, w którym zastosowano metody termiczne (TG-DTA) w uzupełnieniu do prowadzonych prac nad optymalizacją procesu regeneracji termicznej. Proces regeneracji termicznej jako sposób utylizacji zużytych mas formierskich i rdzeniowych w stosunku do innych rodzajów regeneracji zużytych mas jest bardziej kosztowny, ale jednocześnie dający w większości przypadków najlepsze oczyszczenie osnowy mineralnej ze spoiw organicznych. Stąd zastosowanie metod analizy termicznej (TG-DTA), poprzez określenie zakresu temperatury, w którym dochodzi do degradacji, a następnie destrukcji związanych spoiw organicznych w masie, może przyczynić się do optymalizacji procesu regeneracji termicznej i zmniejszenia kosztów jego realizacji.

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Ocena gęstości właściwej iłów na podstawie strat przy prażeniu

Tankiewicz M., Stróżyk J.

Górnictwo Odkrywkowe

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2013

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R. 54, nr 1

33--36

PL

W artykule przedstawiono wyniki badań laboratoryjnych gęstości właściwej iłów z niewielką zawartością substancji organicznej. Badania wykonano dla wybranych 35 próbek iłów i iłów pylastych z Dolnego Śląska. Dla każdej próby wykonano oznaczenia gęstości właściwej oraz zawartości substancji organicznej metodą prażenia w 800°C. Do oznaczonych wartości strat przy prażeniu wprowadzono poprawkę ze względu na utratę wody związanej. Wyniki doświadczeń przedstawiono w postaci zależności gęstości właściwej od poprawionych strat przy prażeniu. Zestawiono je z równaniami Skemptona i Petleya, Okruszko oraz Marcinka i Spychalskiego. Zaproponowano uproszczony wzór zależności gęstości właściwej od wartości strat przy prażeniu dla iłów.

EN

The paper presents results of laboratory investigations of specific gravity of clay with low organic matter content. The investigation have been made on selected 35 samples of clay and silty clay from Lower Silesia. For every sample the specific gravity and ignition loss (by firing at 800°C) have been estimated. To loss in weight on ignition the correction for bound water have been used. The results of examination are presented as relation between the specific gravity and corrected ignition loss. They were compared with equations of Skempton and Petley, Okruszko and Marcinek and Spychalski. Finally, simplified formula for specific gravity for clays have been proposed.

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The geochemical profile of bottom sediments in the Domiąża (Oder River estuary, northwest Poland)

Piotrowski S., Łaba-Mydłowska E.

Oceanological and Hydrobiological Studies

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2003

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Vol. 32, No. 4

79-115

EN

The Domiąża is a fragment of the Oder river estuary situated north of Szczecin. This area is exposed to complex hydrological processes and strong anthropogenic pressure. Key physical and chemical parameters of the Domiąża sediments (fraction < 2 mm), e.g., dry residue (Ds), ignition loss (Iz), CaCO3 and organic carbon content, show high coefficients of variation (over 60%). Similar variation is typical of the heavy metal concentrations (Cu, Zn, Pb, Co, Cd and Hg) and the organic carbon content in the fraction smaller than 0.20 mm. The spatial distribution of the examined parameters in the Domiąża sediments results from the dynamics of this environment, especially the heavy watercraft traffic and the continuous dredging of the Szczecin-Świnoujście water lane. Concentrations of Cd, Cu, Zn, Pb and Co found in the Domiąża sediments are higher than those found in the geochemical background of Poland, while concentrations of mercury are comparable. Moreover, the concentrations of Cu, Zn, Pb and Cd found in the Domiąża sediments are higher than the average concentrations of these metals in adjacent areas (Oder River, Dąbie Lake, Szczecin Lagoon), but the concentrations of Hg and Co are comparable or lower depending on the area of reference. A survey of heavy metals concentrations conducted in 1999 detected higher than average concentrations of Cu, Zn, Pb, and particularly Co (twice) and Hg (over thirty times), and lower concentrations of Cd in comparison with the average levels of 1996. The reason for these differences was the selective inflow of heavy metals to the Domiąża area after the disastrous flood of 1997.