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Tytuł:
Microstructure and Surface Morphology of Nanocrystalline Silver Silicates
Autorzy:
Duhan, S.
Powiązania:
https://bibliotekanauki.pl/articles/1489860.pdf
Data publikacji:
2012-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
61.46.Hk
78.67.Bf
Opis:
Microstructure and surface morphology of AgO nanocrystallites (25 nm) supported on $SiO_2$ and subjected to heat treatment in air up to 500C have been studied by transmission electron microscopy, scanning electron microscopy, and the Fourier transform infrared spectroscopy measurements. It has been found that heating at 500C resulted in spreading of AgO over silica and formation of quasi two-dimensional amorphous phase (silicate precursor) exhibiting very weak band at $566 cm^{-1}$ have appeared in the Fourier transform infrared spectroscopy. Nanocrystalline silver silicate of undefined structure formed at 300-500C.
Źródło:
Acta Physica Polonica A; 2012, 121, 3; 636-638
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of the static and dynamic properties of tho-type silicates
Autorzy:
Cauchi, R.
Grima, J. N.
Powiązania:
https://bibliotekanauki.pl/articles/1954447.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska
Tematy:
auxetics
zeolites
thomsonite
molecular dynamics
Opis:
Auxetic materials are materials exhibiting a negative Poisson’s ratio in one of their planes. This phenomenon has been studied in various materials. Zeolites are crystalline substances whose structure is characterised by the framework of linked tetrahedra, each consisting of four oxygen atoms surrounding a cation. The resulting interstitial spaces make them efficient for use as adsorbents and molecular sieves, and many studies have been focused on this aspect. Some of these zeolites may exhibit auxeticity at least in one of their planes. THO (and similar systems, such as NAT and EDI) together with the all-silica equivalent of these have been studied extensively via static simulations for their negative Poisson’s ratio in the (001) plane. In this paper a study of the all-silica equivalent of THO has been carried out via both static and dynamic simulations using the same force-field, where the system was subjected to stress along the x direction. The hypothesised semi-rigid mechanism of deformation, proposed by Grima et al. was then projected over this framework. The results obtained confirmed auxeticity along this plane by means of the COMPASS force-field, in both static and dynamic studies and compared well with the proposed mechanism of semi-rigid rotating polygons. It also showed that as the Young’s modulus of this mechanism increases other mechanisms of deformation increase in importance.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2014, 18, 1; 5-65
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phosphates of ornithogenic soils on the volcanic King George Island (Maritime Antarctic)
Autorzy:
Tatur, Andrzej
Barczuk, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2057478.pdf
Data publikacji:
1984
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Maritime Antarctica
mineralogy
ornithogenic soils
phosphates
phosphatization of silicates
Źródło:
Polish Polar Research; 1984, 5, 1-2; 61-97
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of organic coatings containing pigments with surface modified with a layer of ZnFe2O4
Autorzy:
Nechvílová, K
Kalendová, A
Powiązania:
https://bibliotekanauki.pl/articles/102579.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
zinc ferrite
silicates
surface protection
organic coatings
Opis:
This work is focussed on the properties of organic coatings containing pigments whose surface was chemically coated with zinc ferrite (ZnFe2O4) layer. Four silicate types with different particle shapes were selected as the cores: diatomite, talc, kaolin and wollastonite. The untreated particles exhibit a barrier effect. The aim of this project was to apply the surface treatment approach with a view to enhancing not only the model paint films’ anticorrosion properties but also their resistance to physico- mechanical tests pursuant to ISO standards (cupping, bending, impact, adhesion). Other parameters examined included: particle size and morphology, density of the modified pigment, oil consumption, pH, conductivity, and electrochemical properties of the paint film. A solvent-based epoxy-ester resin was used as the binder and also served as the reference material. The pigment volume concentration (PVC) was 1% and 10%. During the last stage of the experiment, the paint films were exposed to a corrosive environment stimulating seaside conditions or conditions roads treated with rock salt. The accelerated cyclic corrosion test in a neutral salt mist atmosphere was conducted for 864 hours. The results served to ascertain a suitable environment for organic coatings.
Źródło:
Advances in Science and Technology. Research Journal; 2015, 9, 28; 51-55
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mineralogy of the Baszkówka chondrite (L5 S1): new data on silicates, opaques and minor minerals
Autorzy:
Borucki, J.
Stępniewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059302.pdf
Data publikacji:
2001
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Baszkówka
meteorites
ordinary chondrites
minerals
spinel
picotite
Opis:
The mineral composition of the Baszkówka meteorite comprises: olivine, pyroxenes, plagioclase, Fe,Ni metal, troilite and chromite with minor chlorapatite, whitlockite, magnetite, haematite, spinel, idaite, calcite and native Cu. A rare variety of spinel (picotite), probably the oldest among the minerals of Baszkówka, was identified in the only two chondrules named: panda and chevron. The composition of the olivine (Fa 26.2š1.8 wt.%) and the high degree of chondrite homogenisation, a result of thermal metamorphism, are consistent with earlier results and indicate the L5 group. No distinct shock effects were observed in Baszkówka, classified as S1. Troilite-Fe,Ni and Fe,Ni metal lumps are defined and interpreted as molten planetesimals impact splashes.
Źródło:
Geological Quarterly; 2001, 45, 3; 229-256
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Inorganic Binder Bridges Destruction after Thermal Load
Autorzy:
Vaskova, I.
Conev, M.
Powiązania:
https://bibliotekanauki.pl/articles/380132.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inorganic binder
dehydration
alkali silicates
geopolymer
adhesive force
cohesive forces
spoiwo nieorganiczne
odwodnienie
krzemiany alkaliczne
geopolimer
przyczepność
Opis:
Recently, the use of inorganic binders cured by heat as a progressive technology for large scale production of cores is widely discussed topic in aluminium foundries. As practical experiences show, knock-out properties of inorganic binders were significantly increased, although they cannot overcome organic based binder systems. This paper contains information about hot curing processes based on alkali silicate and geopolymer binder systems for core making. Main differences between hot cured geopolymers and hot cured alkali silicate based inorganic binders are discussed. Theory of geopolymer binder states, that binder bridge destruction is mainly of adhesive character. The main aim of this research paper was to examine binder bridge destruction of alkali silicate and geopolymer binder systems. In order to fulfil this objective, sample parts were submitted to defined thermal load, broken and by using SEM analysis, binder bridge destruction mechanism was observed. Results showed that geopolymer binder system examined within this investigation does not have mainly adhesive destruction of binder bridges, however the ratio of adhesive-cohesive to cohesive destruction is higher than by use of alkali silicate based binder systems, therefore better knock-out properties can be expected.
Źródło:
Archives of Foundry Engineering; 2019, 2; 25-28
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decoring Behaviour of Chosen Moulding Materials with Alkali Silicate Based Inorganic Binders
Autorzy:
Conev, M.
Vasková, I.
Hrubovčáková, M.
Hajdúch, P.
Powiązania:
https://bibliotekanauki.pl/articles/356323.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inorganic binder
alkali silicates
moulding material
knock-out properties
Opis:
This paper contains basic information about new processes for cores for cylinder heads production with alkali silicate based inorganic binders. Inorganic binders are coming back to the foreground due to their ecologically friendly nature and new technologies for cores production and new binder systems were developed. Basically these binder systems are modified alkali silicates and therefore they carry some well-known unfavourable properties with their usage. To compensate these disadvantages, the binder systems are working with additives which are most often in powder form and are added in the moulding material. This paper deals with decoring behaviour of different moulding sands as well as the influence of chosen additives on knock-out properties in laboratory terms. For this purpose, specific methods of specimen production are described. Developed methods are then used to compare decoring behaviour of chosen sands and binder systems.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 703-706
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upgrading valuable mineralization and rejecting magnesium silicates by pre-concentration of mafic ores
Autorzy:
Altun, N. E.
Weatherwax, T.
Klein, B.
Powiązania:
https://bibliotekanauki.pl/articles/109691.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mafic ores
preconcentration
dense media separation
metallic sulphides
ore mineralogy
Opis:
Amenability of mafic ores to pre-concentration was investigated with respect to ore mineraliza-tion characteristics. For the pre-concentration tests seven ores from various nickel-copper operations at Sudbury, Ontario were subjected to dense medium separation. Size assays of metal values, i.e. distribution of nickel and copper with respect to size fractions, were also determined. The ores were assessed in three categories of valuable mineralization as massive pure sulphides, coarse massive sulphide grains and disseminated sulphides. For ores with massive pure sulphides and coarse massive sulphide grains even a size classification based pre-concentration route could be sought since a clear trend of metal enrichment was identified towards finer fractions. Orebodies of similar mineralogy had similar responses to pre-concentration tests. The best results were for those ore bodies with a distinct differentiation between mineralization and gangue, i.e. the ores with massive pure sulphides, where nickel recoveries of 97% and mass rejections of 38-53% were achieved. Similar results were obtained for ores with coarse massive sulphides. For disseminated sulphide mineralogy relatively lower mass rejection was attained with acceptable recoveries of metals. Rejection of magnesium bearing gangue, such as talc, was identified as another benefit of pre-concentration. The extent of magnesium rejection occurred as a function of ore mineralogy. Clear distinction between valuable mineralization and gangue provided preferential magnesium rejection at high levels with no or minor metal losses.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 203-215
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effective separation of specularite and aegirite using chitosan as a novel depressant
Autorzy:
Li, Mingyang
Zhang, Pengpeng
Gao, Xiangpeng
Tong, Xiong
Xie, Xian
Powiązania:
https://bibliotekanauki.pl/articles/2175424.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
iron-bearing silicates
aegirite
specularite
chitosan
depressant
Opis:
As a typical iron-bearing silicate gangue, aegirite often associates with specularite. Due to the iron element contained in aegirite, it has similar surface properties to specularite. Flotation is by far one of the most efficient methods of processing this kind of iron ore. But the traditional depressants unable to take action in the separation of specularite and aegirite. Chitosan was used as a novel depressant to attempt to separate specularite from aegirite through microflotation tests, adsorption tests, contact angle measurements, Zeta potential measurements, and XPS analysis. The flotation results indicate that chitosan show more strong depression effect on specularite than aegirite. Zeta potential measurements, contact angle measurements and adsorption tests demonstrate that chitosan is more inclined to adsorb on the specularite surface than aegirite, which hinders the subsequent adsorption of collector sodium oleate and increases difference in hydrophobicity between the two minerals. The XPS results of specularite validate the adsorption of chitosan on specularite, and illustrate that electrons of chitosan were partially transferred to oxygen and iron atoms in specularite during the adsorption process.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 151692
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving spodumene flotation using a mixed cationic and anionic collector
Autorzy:
Wang, Y.
Zhu, G.
Yu, F.
Lu, D.
Wang, L.
Zhao, Y.
Zheng, H.
Powiązania:
https://bibliotekanauki.pl/articles/109883.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
spodumene
lithium
silicates
flotation
anionic surfactant
cationic surfactant
Opis:
Lithium, a rare-earth element, has been in increasing demand. Spodumene flotation is an important and challenging step for lithium extraction and production from lithium ore. In the present work, flotation tests for three pure minerals (i.e., spodumene, quartz and feldspar) and a real spodumene ore were carried out at laboratory scale. The results showed that YOA, a mixture of oleic acid and dodecylamine with the molar ration of 10:1, could be used as collector to produce a spodumene concentrate with grade of 5.59% Li2O from the feed ore with grade of 1.48% Li2O where 85.24% of Li2O was recovered to the concentrate. The measured zeta potential, contact angle and adsorption capacity indicated that YOA was preferentially adsorbed on spodumene instead of on quartz or feldspar, with the spodumene surface being more hydrophobic than that of feldspar or quartz. The adsorption energies of YOA on spodumene were calculated and the results provided insights into the superior flotation performance obtained in the present work.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 567-577
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review and perspective of high-k dielectrics on silicon
Autorzy:
Hall, S.
Buiu, O.
Mitrovic, I. Z.
Lu, Y.
Davey, W. M.
Powiązania:
https://bibliotekanauki.pl/articles/309000.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
high-k dielectrics
dielectric constant
hafnia
interfacial layer
aluminates
silicates
Opis:
The paper reviews recent work in the area of high-k dielectrics for application as the gate oxide in advanced MOSFETs. Following a review of relevant dielectric physics, we discuss challenges and issues relating to characterization of the dielectrics, which are compounded by electron trapping phenomena in the microsecond regime. Nearly all practical methods of preparation result in a thin interfacial layer generally of the form SiOx or a mixed oxide between Si and the high-k so that the extraction of the dielectric constant is complicated and values must be qualified by error analysis. The discussion is initially focussed on HfO2 but recognizing the propensity for crystallization of that material at modest temperatures, we discuss and review also, hafnia silicates and aluminates which have the potential for integration into a full CMOS process. The paper is concluded with a perspective on material contenders for the "end of road map" at the 22 nm node.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 2; 33-43
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pigments precipitated from chromate post-galvanic solutions in emulsion systems
Autorzy:
Klapiszewska, B.
Krysztafkiewicz, A.
Jesionowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/779987.pdf
Data publikacji:
2007
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
pigment zielony
pigmenty
krzemian chromu strącany
układ emulsyjny
odpady pogalwaniczne
green pigments
precipitated chromium(III) silicates
emulsion system
post-galvanic wastes
Opis:
Studies were conducted on the production of chromium(III) silicates, the green pro-ecological pigments. The pigments were precipitated from sodium silicate and chromium(III) sulphate solutions in the system of two emulsions prepared in hexane in the presence of a non-ionic surfactant as an emulsifier. The chromium(III) sulphate represented a reduction product of chromate(VI) compounds present in post-galvanic wastes. The reduction agent involved metanal in an acidic medium. The obtained products were subjected to a comprehensive physicochemical analysis, their dispersive and morphological properties were determined. The precipitated green products exhibiting intense colour, were uniform and their particles manifested a low tendency to form agglomerate structures.
Źródło:
Polish Journal of Chemical Technology; 2007, 9, 2; 27-29
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorptive performance of MCM-41 towards hg(II) in water. Adsorption and desorption studies
Autorzy:
Zhai, Q. Z.
Hu, W.-H.
Guo, X.-Y.
Powiązania:
https://bibliotekanauki.pl/articles/208154.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electron microscopy
mesoporous silicates
cetyltrimethylammonium bromide
adsorption conditions
mikroskopia elektronowa
krzemiany mezoporowate
bromek cetyltrimethylammonium
warunki adsorpcyjne
Opis:
MCM-41 mesoporous material was prepared under a standard conditions by using cetyltrime-thylammonium bromide as a structure-directing agent and tetraethyl orthosilicate as silica source from the liquid phase at 80 °C. Powder X-ray diffraction and scanning electron microscopy used to characterize the product, showed that the MCM-41material had an average particle size of 110 nm. The synthesized material was used to investigate the effects of acidity, adsorption time, the concentration of Hg2+, adsorbent dosage and temperature on the adsorption of Hg2+. The results showed that the optimal adsorptive conditions were: pH 5.0, m(MCM-41):mHg2+ 6.67, temperature 20 °C and contact adsorption time 60 min, for the initial Hg2+concentration of 1.0 mg/cm3. The maximum adsorptive amount of Hg2+ was 56.48 mg Hg2+/g MCM-41. The results of the desorptive effect of three desorption agents such as HCl, HNO3 and HAc showed that the best desorbent was HCl at the concentration of 0.10 mol/dm3. The highest desorption efficiency was 77.21% for the desorption time 2 h.
Źródło:
Environment Protection Engineering; 2016, 42, 1; 5-15
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polymorphic transformations of dicalcium silicates in steel slags used in the production of road aggregates
Przemiany polimorficzne krzemianów dwuwapniowych w żużlach stalowniczych stosowanych do produkcji kruszywa drogowego
Autorzy:
Jonczy, Iwona
Grzesik, Bartłomiej
Powiązania:
https://bibliotekanauki.pl/articles/2069762.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
steel slag
dicalcium silicate
artificial aggregate
żużel stalowniczy
krzemian dwuwapniowy
kruszywo sztuczne
Opis:
This paper presents results of mineralogical and chemical research connected with the polymorphic transformations of dicalcium silicates in aggregate based on open-hearth slag and also slags from the current production of EAF (electric arc furnaces), and LF (ladle furnaces). Particular attention was paid to the transformation of the polymorph β-Caub>2[SiO4] into the variant γ-Ca2[SiO4], which is undesirable from the perspective of using steel slags in road construction. A full mineralogical characterization of the tested metallurgical slags enabled the verification of the effectiveness of detecting the decomposition of dicalcium silicate in observations in UV light in line with the PN-EN 1744-1+A1:2013-05 standard. On the basis of the conducted research, it was found that in the aggregate based on open-hearth slags and in the EAF furnace slag, dicalcium silicates are mainly represented by the β-Ca2[SiO4] polymorph, accompanied by α’-Ca2[SiO4]. The slag from the LF furnace was characterized by a different composition, with a strong advantage (57%) of the α’-Ca2[SiO4] variety, with a 1% share of the β-Ca2[SiO4] and 15% of the γ-Ca2[SiO4]. It was found that the transformation of β-Ca2[SiO4] into γ-Ca2[SiO4] can take place only under certain conditions in the metallurgical process, but the process is not influenced by hyperergenic factors, as evidenced by the fact that after more than 100 years of storage of open-hearth slag, on the basis of which the aggregate was produced, it was primarily marked with all the variants of β-Ca2[SiO4], without the polymorph γ-Ca2[SiO4]. The comprehensive characterization of the slag phase composition requires use of an appropriately selected research methodology; this is of key importance prior to the secondary use of this material, especially in the presence of the γ-Ca2[SiO4] polymorph. It has been determined that the most accurate test results are obtained using the XRD technique. The method of determining the decomposition of dicalcium silicate according to the PN-EN 1744-1+A1:2013-05 standard proved to be unreliable. It seems that in the situation of using LF slag as an artificial aggregate, taking the test results according to the method described in the PN-EN 1744-1+A1:2013-05 standard as being decisive is very risky, especially on a large scale (e.g. in communication construction).
W artykule przedstawiono wyniki badań mineralogiczno-chemicznych dotyczące przemian polimorficznych krzemianów dwuwapniowych w kruszywie na bazie żużli martenowskich, a także w żużlach z bieżącej produkcji pieca elektrycznego EA F (Electric Arc Furnace) oraz pieca kadziowego LF (Ladle Furnace). Szczególną uwagę zwrócono na przeobrażenia polimorfu β-Ca2[SiO4] w odmianę γ-Ca2[SiO4], co jest niepożądanym zjawiskiem z punktu widzenia wykorzystania żużli stalowniczych w budownictwie drogowym. Pełna charakterystyka mineralogiczna badanych żużli posłużyła do weryfikacji skuteczności wykrywania rozkładu krzemianu dwuwapniowego w obserwacjach w świetle UV zgodnie z normą PN-EN 1744-1+A1:2013-05. Na podstawie przeprowadzonych badań stwierdzono, że w kruszywie na bazie żużli martenowskich oraz w żużlu z pieca EAF krzemiany dwuwapniowe są reprezentowane przede wszystkim przez odmianę β-Ca2[SiO4], której towarzyszy α’-Ca2[SiO4]. Żużel z pieca LF charakteryzował się natomiast odmiennym składem, z silną przewagą (57%) odmiany α’-Ca2[SiO4], przy 1% udziale odmiany β-Ca2[SiO4] oraz przy 15% zawartości odmiany γ-Ca2[SiO4]. Stwierdzono, że przemiana β-Ca2[SiO4] w γ-Ca2[SiO4] może zachodzić tylko w określonych warunkach w procesie metalurgicznym, na proces ten nie mają natomiast wpływu czynniki hipergeniczne, o czym może świadczyć fakt, że po około 100-letnim okresie składowania żużla martenowskiego, na bazie którego wyprodukowano kruszywo, oznaczono w nim przede wszystkim odmianę β-Ca2[SiO4], nie stwierdzając polimorfu γ-Ca2[SiO4]. Kompleksowa charakterystyka składu fazowego żużla wymaga zastosowania odpowiednio dobranej metodyki badawczej, zwłaszcza pod kątem obecności polimorfu γ-Ca2[SiO4], co ma kluczowe znaczenie przed wtórnym wykorzystaniem tego materiału. Stwierdzono, że najdokładniejsze wyniki badań uzyskuje się przy użyciu techniki XRD. Metoda oznaczania rozkładu krzemianu dwuwapniowego wg normy PN-EN 1744-1+A1:2013-05 okazała się zawodna. Wydaje się, że w sytuacji wykorzystania żużla po produkcji pieca LF jako kruszywa sztucznego, zwłaszcza na dużą skalę, np. w budownictwie komunikacyjnym, przyjęcie wyników badań zgodnie z metodą opisaną w normie PN-EN 1744-1+A1:2013-05 jako decydujące jest bardzo ryzykowne.
Źródło:
Gospodarka Surowcami Mineralnymi; 2021, 37, 4; 97--116
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of silicates on methane digestion of sewage sludge
Wpływ krzemianów na proces fermentacji metanowej osadów
Autorzy:
Wiśniowska, E.
Włodarczyk-Makuła, M.
Powiązania:
https://bibliotekanauki.pl/articles/297377.pdf
Data publikacji:
2016
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
ammonium nitrogen
phosphates
methane digestion
silicate
reject water
sequential analysis of phosphorus
azot amonowy
fosforany
fermentacja metanowa
krzemiany
ciecze osadowe
analiza sekwencyjna fosforu
Opis:
Effect of clinoptylolite and bentonite admixture on balance of ammonium nitrogen and phosphates in reject water during methane digestion of excess sludge was evaluated. Concentration of ammonium nitrogen and phosphates in reject water separated from the sludge with silicates amendment and without it (control sludge) was analysed to compare the effectiveness of biogenic compounds removal. Simultaneously effect of silicates addition on biogas production and fractions of phosphorus was analysed. Doses of silicates at level no higher than used in wastewater treatment by activated sludge process were added to methane digestion chamber. The doses were equal to 0.5, 1.0 and 2.0 g · L–1. Research work was conducted under laboratory conditions for 21 days. Admixture of silicates did not decrease concentration of ammonium nitrogen in reject water but reduced phosphates content in this medium compared to control sample. Under experimental conditions clinoptylolite was more effective in biogens removal than bentonite. Increase in biogas production was especially visible during days from 1 to 16; after that time it decreased in samples with silicates more rapidly than in control reactor. However silicates admixture increased total biogas production by maximum 17% compared to control sample. Clinoptylolite and bentonite admixture increased percent shares of phosphorus associated with carbonates in sewage sludge. Increase in II-nd fraction share was proportional to the dose of silicates. In control sample the dominant fraction of phosphorus in sewage sludge was the III-rd; in samples with silicate admixture percent shares of II-nd nad III-rd fractions were comparable. The conclusion from the research work is as follows: at doses used in wastewater treatment technology to support activated sludge process silicates do not affect the composition of reject water significantly. However addition of natural sorbents positively affected anaerobic degradation of sewage sludge.
W badaniach analizowano wpływ dodatku dwóch rodzajów krzemianów - klinoptylolitu i bentonitu na stężenie azotu amonowego oraz fosforanów w cieczach osadowych podczas fermentacji metanowej nadmiernych osadów ściekowych pobranych z oczyszczalni z biologicznym usuwaniem związków biogennych. Wyniki porównywano z uzyskiwanymi w próbkach bez domieszki krzemianów. Analizowano także wpływ dodatku krzemianów na produkcję biogazu oraz frakcje fosforu w osadach. Stosowane dawki krzemianów były porównywalne do wykorzystywanych w procesach tlenowego rozkładu zanieczyszczeń w technologii osadu czynnego. Stosowane dawki wyniosły 0,5, 1 i 2 g krzemianu/dm3. Fermentację osadów prowadzono w warunkach laboratoryjnych przez 21 dób. Właściwości fizyczno-chemiczne oznaczano w dniu 0 oraz po 7, 14 i 21 dobach. Po wprowadzeniu krzemianów nie uzyskano zmniejszenia stężenia azotu amonowego w cieczach osadowych, jednakże zaobserwowano obniżenie stężenia fosforanów w porównaniu z próbką kontrolną. W warunkach eksperymentu klinoptylolit był bardziej efektywny w usuwaniu związków biogennych niż bentonit. Obecność krzemianów miała wpływ na wzrost produkcji biogazu o ok. 17% w porównaniu z próbką kontrolną. Było to szczególnie widoczne w pierwszych 16 dniach prowadzenia procesu. Po tym czasie w reaktorach zawierających krzemiany nastąpiło szybsze załamanie się produkcji biogazu niż w próbce kontrolnej. Ponadto w obecności krzemianów zwiększył się udział w osadzie frakcji fosforu zasocjowanej z węglanami (frakcja II). Wzrost udziału frakcji II był proporcjonalny do wzrostu dawki krzemianów. W próbce kontrolnej dominującą frakcją była frakcja III. Na podstawie przeprowadzonych badań można stwierdzić, że w dawkach stosowanych w technologii ścieków do wspomagania procesów biologicznych krzemiany nie powodowały istotnych statystycznie zmian stężenia biogenów w cieczach osadowych w porównaniu z próbką kontrolną. Dodatek krzemianów pozytywnie wpływał na przebieg fermentacji metanowej osadów, m.in. umożliwiając zwiększenie ilości wytwarzanego biogazu.
Źródło:
Inżynieria i Ochrona Środowiska; 2016, 19, 4; 493-502
1505-3695
2391-7253
Pojawia się w:
Inżynieria i Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 22

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