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1
Content available Assessment of Foundry Chromite Sand Crushability under Thermal-Mechanical Loading
Kabasele Jonathan K., Nyembwe Kasongo D., Polzin H.
Archives of Foundry Engineering
|
2023
|
Vol. 23, iss. 3
16--21
EN
When used for sand casting, foundry sand is stressed in several ways. These stresses, thermal and mechanical, compromise the grain integrity, resulting in size reduction and the production of small particles to the point where the sand is no longer viable for sand casting. This study evaluates the crushability of chromite sand, a crucial characteristic for determining how resistant sand is to size reduction by crushing. To replicate the heat and mechanical strain that sand is subjected to during the industrial sand-casting process, a sinter furnace and rod mill were employed. After nine minutes of heat and mechanical stress application, the crushing ratio, which was used to gauge the crushability of chromite sand, ranged from 1.72 to 1.92 for all samples. There were differences in the rate at which fine particles were produced among the samples, with sample E producing the highest proportion of fine particles in the same length of time. Understanding the properties that control the crushability performance of chromite sand will enable foundries to buy chromite sand with higher recycling yield, reducing the environmental impact of waste foundry sand and eliminating the risk to the workforce's pulmonary health in line with the current industry standards. Foundries will also be able to optimize the current industrial process while continually pushing for innovative foundry technologies and materials.
2
Content available Application of Non-Silica Sands for High Quality Castings
Beňo J., Poręba M., Bajer T.
Archives of Metallurgy and Materials
|
2021
|
Vol. 66, iss. 1
25--30
EN
The goal of this article is to application of non-silica sands based on alumininosilicates as an alternative of traditionally used chromite sand for alloyed steel and iron castings. Basic parameters as bulk density, pH value of water suspension, refractoriness, grain shape of the testing sands were evaluated. Also mechanical properties of furan no-bake moulding mixtures with testing sand were determined. Finally, the influence of non-silica sand on casting quality was evaluated via semi-scale under normal casting production for sand characterization. Optimization of production process and production costs were described.
3
Piasek syntetyczny LK-SAND (potencjalne źródło zastąpienia piasku chromitowego)
Wróbel J.
Przegląd Odlewnictwa
|
2018
|
Vol. 68, nr 9-10
328--331
PL
W pracy przedstawiono wyniki prób zastosowania piasku synte-tycznego LK-Sand w miejsce piasku na osnowie chromitowej. Próby techniczne poprzedzono porównaniem właściwości piasku o osnowie chromitowej, piasku syntetycznego LK-Sand oraz podano podstawowe informacje na temat mulitu. W dalszej części artykułu opisano próby techniczne jakie przeprowadzono z użyciem LK-SAND-u w Hucie Małapanew w Ozimku. Zaprezentowano odlew w którym testowano ten syntetyczny piasek. Opisano technologie wykonania rdzeni jak i formy. Następnie zaprezentowano wyniki testu które skomentowano w podsumowaniu.
EN
The results of efforts to apply the synthetic sand, LK-Sand as a substitution of the sand on the chromite matrix are presented in the hereby paper.Technical tests preceded by comparisons of properties the sand with the chromite matrix and of the synthetic LK-Sand as well as the basie information concerning the mullite were given in the artickle. Technical tests performed with LK-Sand in steelworks Małapanew in Ozimek were described. The casting in which this synthetic sand wastested, was presented. Technologies of producing cores and moulds were described. Then the obtained test results were shown and commented on, in conclusions.
4
Content available Influence of sand base preparation on properties of chromite moulding sands with sodium silicate hardened with selected methods
Stachowicz M., Granat K., Pałyga Ł.
Archives of Metallurgy and Materials
|
2017
|
Vol. 62, iss. 1
379--383
EN
The paper presents a research on the relation between thermal preparation of chromite sand base of moulding sands containing sodium silicate, hardened with selected physical and chemical methods, and structure of the created bonding bridges. Test specimens were prepared of chromite sand - fresh or baked at 950°C for 10 or 24 hours - mixed with 0.5 wt.% of the selected non-modified inorganic binder and, after forming, were hardened with CO2 or liquid esters, dried traditionally or heated with microwaves at 2.45 GHz. It was shown on the grounds of SEM observations that the time of baking the base sand and the hardening method significantly affect structure of the bonding bridges and are correlated with mechanical properties of the moulding sands. It was found that hardening chromite-based moulding mixtures with physical methods is much more favourable than hardening with chemical methods, guaranteeing also more than ten times higher mechanical properties.
5
Content available Effect of Temperature on Chromite-Based Moulding Sands Bonded with Sodium Silicate
Stachowicz M., Kamiński M., Granat K., Pałyga Ł.
Archives of Foundry Engineering
|
2017
|
Vol. 17, iss. 2
95--100
EN
In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within 100 to 1200°C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.
6
Content available Determination of Chromite Sands Suitability for Use in Moulding Sands
Stec K., Podwórny J., Psiuk B., Kozakiewicz Ł.
Archives of Foundry Engineering
|
2017
|
Vol. 17, iss. 2
107--110
EN
Using the available analytical methods, including the determination of chemical composition using wavelength-dispersive X-ray fluorescent spectroscopy technique and phase composition determined using X-ray diffraction, microstructural observations in a high-resolution scanning microscope equipped with an X-ray microanalysis system as well as determination of characteristic softening and sintering temperatures using high-temperature microscope, the properties of particular chromite sands were defined. For the study has been typed reference sand with chemical properties, physical and thermal, treated as standard, and the sands of the regeneration process and the grinding process. Using these kinds of sand in foundries resulted in the occurrence of the phenomenon of the molding mass sintering. Impurities were identified and causes of sintering of a moulding sand based on chromite sand were characterized. Next, research methods enabling a quick evaluation of chromite sand suitability for use in the preparation of moulding sands were selected.
7
Piasek chromitowy a masa furanowa (czyli na co zwracać uwagę aby pomagał, a nie szkodził)
Wróbel J.
Przegląd Odlewnictwa
|
2016
|
Vol. 66, nr 9-10
466--470
PL
W pracy przedstawiono wpływ najważniejszych właściwości piasku o osnowie chromitowej w kontekście jego wiązania w masie furanowej i jego wpływie na występowania wad na odlewach. Opisane właściwości w opinii autora w głównej mierze stanowią, o jakości piasku i o jego przydatności, w procesie formowania. Nie dotrzymanie tych właściwości może skutkować wadami na odlewach i/lub problemami w samym procesie wiązania masy formierskiej. Przekroczenia opisywanych czynników informują o niskiej jakości dostarczonego piasku który zamiast pomagać – szkodzi. Niniejszy referat jest także próbą odpowiedzi na często stawiane przez dostawców piasku chromitowego pytanie – „co jest dla was najważniejsze”.
EN
The paper presents the influence of major properties of the chromite sand in the context of it`s binding in furan mas and defects on castings. Described properties in the author's opinion they largely represent about quality of the sand and about his usefulness in the molding process. Failure these properties may result defects on the castings and/or problems in the bonding process molding sand. Exceeding the described factors informing about low quality delivered sand which instead of helping – harms. This paper is also an attempt to answer for frequently asked question by delivers of chromite sand – “what is for you the most important”.
8
Content available Effective Laboratory Method of Chromite Content Estimation in Reclaimed Sands
Ignaszak Z., Prunier J. B.
Archives of Foundry Engineering
|
2016
|
Vol. 16, iss. 3
162--166
EN
The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid. It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium). The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.
9
Content available Effect of Temperature on Chromite-Based Moulding Sands Bonded with Sodium Silicate
Stachowicz M., Kamiński M., Granat K., Pałyga Ł.
Archives of Foundry Engineering
|
2016
|
Vol. 16, iss. 4
147--152
EN
In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within 100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.
10
Content available remote Oznaczanie zawartości SiO2 w piasku chromitowym metodą spektroskopii w podczerwieni
Bobrowski A., Holtzer M.
Archives of Foundry Engineering
|
2010
|
Vol. 10, iss. 2 spec.
19--22
PL
W pracy przedstawiono wyniki oznaczania zawartości SiO2 w piasku chromitowym oraz w regeneracie piasku chromitowego metodą spektroskopii w podczerwieni (FTIR) i metodą chemiczną. Ze względu na interferencyjne oddziaływanie składników badanych próbek z pasmem analitycznym, charakterystycznym dla krzemionki (798 i 779 cm-1), do analizy przyjęto jako pasmo analityczne pasmo przy liczbie falowej 1080 cm-1. Analiza regresji wykazała zadawalającą zgodność wyników uzyskanych metodą FTIR i metodą chemiczną, szczególnie przy wyższych zawartościach SiO2.
EN
The results of determination of the SiO2 content in a chromite sand and in a reclaimer chromite sand by the infrared spectroscopy (FTIR) and by the chemical method, are presented in the paper. Due to the interference of components of the investigated samples with the analytical band characteristic for silica (798 and 779 -1), the band at a wave number of 1080 cm-1 was accepted as the analytical band in examinations. The regression analysis exhibited the satisfactory compatibility of the results obtained by the FTIR method and by the chemical one, especially at the higher SiO2 content.
11
Content available remote Badania mas formierskich i rdzeniowych przeznaczonych do produkcji odlewów staliwnych z zastosowaniem nowego spoiwa geopolimerowego
Pezarski F., Maniowski Z., Izdebska-Szanda I., Smoluchowska E.
Archiwum Odlewnictwa
|
2006
|
R. 6, nr 20
65--70
PL
W artykule przedstawiono wyniki badań laboratoryjnych właściwości technologicznych mas formierskich samoutwardzalnych z udziałem nowej ekologicznej kompozycji wiążącej - spoiwa geopolimerowego. Przedstawiono porównanie właściwości technologicznych tych mas z właściwościami mas samoutwardzalnych ze szkłem wodnym typu „floster”. Przedstawiono próby wykonywania mas formierskich, form i odlewów staliwnych z zastosowaniem nowej kompozycji wiążącej w warunkach przemysłowych.
EN
The article presents the results of laboratory tests of the technological properties of the self-setting moulding sands prepared with the addition of a new, ecological geopolymer binder composition. The technological properties of these sands were compared with the properties of the self-setting sands made with „floster” sodium silicate binder. The pilot production under industrial conditions of moulding sands, and of moulds and steel castings with the new binding composition was described.
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