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1

The effect of composition and holding time on glaze production using basalt rock as a base

Birawidha David Candra, Miswanto Agus, Setiawan Liston, Prakosa Agus, Dani Umar, Gunawan Gunawan, Arianti Era, Karo-Karo Pulung, Nugroho Totok, Hendronursito Yusup

Physicochemical Problems of Mineral Processing

|

2024

|

Vol. 60, iss. 1

art. no. 177640

EN

This research studied the potential use of local basalt and feldspar from Lampung Province, Indonesia, as glaze materials. Frit(s) are composed of changing basalt-to-feldspar weight ratios of A (30:70), B (50:50), C (70:30), and D (100:0) w/w%. The added 20% boric acid to the total weight reduces the process temperature to 1,000oC with holding times of 1, 4, and 8 hr(s). Based on the chemical composition test of the specimen, the four variations of the sample have SiO2 content above 40%, and the average SiO2/Al2O3 ratio is 4 and 5, which is usually a low-alumina glaze that will cause a glossy effect and have an amorphous structure. At point 2theta 29o, amorphous forms. Quartz (SiO2), albite (NaAlSi3O8), anorthite (CaAl2Si2O8), and coesite (SiO2) phases were discovered in the glaze specimens. The anorthite phase in glass-ceramic glaze gives a transparent glaze color due to the amorphous glassy phase formed during heat treatment. The findings of this study suggest that local materials based on basalt and feldspar may be used as glaze materials to provide a smooth texture and surface; the glaze layer is evenly distributed, can follow the full surface contour of the test specimen, and has low porosity.

2

Application of dodecyl amine/dodium petroleum sulfonate mixed collector in quartz-feldspar flotation separation

He Yuhao, Ren Zijie, Zhu Huimin, Zheng Renjun, Li Mingyang, Song Yuhan, Chen Zhijie

Physicochemical Problems of Mineral Processing

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2024

|

Vol. 60, iss. 1

art. no. 185553

EN

It’s highly challenging to separate feldspar from quartz by flotation owing to their similar crystal structure and physicochemical properties. Using mixed collectors has become a promising method to improve the quartz-feldspar separation. In this study, mixed dodecyl amine (DDA) and sodium petroleum sulfonate (SPS) surfactants were used in the flotation separation of feldspar and quartz, and the adsorption mechanism of mixed collectors and depression mechanisms of two depressants were investigated through zeta potential, contact angle and Fourier transform infrared (FT-IR) spectra. When the pH reached 4.5, the separation of feldspar from quartz was more obvious. In the presence of DDA/SPS collector, the contact angle of feldspar was increased more obviously leading to enhance hydrophobicity. The infrared spectra revealed the interaction of collectors on feldspar surface involved physical and chemical adsorption, whereas the adsorption of collector on quartz was only physical interactions. The use of sodium hexametaphosphate resulted in a significantly enhanced separation performance. The weaker physical adsorption of mixed collector on quartz can be destroyed by sodium hexametaphosphate. This study is beneficial for understanding the collect mechanisms of mixed cationic-anionic surfactants on quartz and feldspar minerals, and promotes the development of advanced feldspar separation techniques.

3

Removing iron impurities from feldspar ore using dry magnetic separation (part one)

Yassin Khaled, Ahmed Mahmoud, Khalifa Mohamed Gamal Eldin Khalifa, Hagrass Ayman Aly

Archives of Mining Sciences

|

2023

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Vol. 68, no. 1

19--33

EN

Feldspar is a basic requirement for glass, ceramics, and other industries. The presence of iron in feldspar is one of the challenging aspects of feldspar processing. To improve the quality of feldspar for use in various industries, dry magnetic separation is one of the best techniques for reducing iron in feldspar, especially in arid regions to overcome the common problem of lack of water resources as well as to reduce the operational cost of the enrichment process. Therefore, dry magnetic separation experiments were carried out to remove the iron content from feldspar ore in the Wadi Umm Harjal area in Egypt to meet the specifications required for different industries. The sample was analysed using XRD, XRF, and optical microscopy, which revealed that it is a mixture of potassium feldspar (microcline/orthoclase), albite, and quartz in the presence of hematite mineral serving as the main iron impurities in addition to the free silica content. The effect of parameters on the activity of the dry high magnetic separators was investigated in addition to cleaning the products. The iron oxide reduced from 0.69% in the head sample to 0.08% after dry high-intensity magnetic separation, and the whiteness increased from 82.01% in the head sample to 95.97% in the separated concentrate. The experimental results showed that there is a possibility to obtain feldspar concentrates with low content of Fe2O3 from the area where according to the results, approximately 88.4% of iron was removed from the head sample.

4

Revisiting flotation mechanisms of the selective separation of alkali feldspars in the presence of NaCl

Karagüzel Cengiz, Çelik Mehmet Sabri

Physicochemical Problems of Mineral Processing

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2022

|

Vol. 58, iss. 5

art. no. 149928

EN

Selective separation of Na-feldspar (NaAl3SiO8) from K-feldspar (KAl3SiO8) by flotation appears to be the only alternative in commonly found mixed-type ore formations. For this purpose, various mechanisms in various studies have been proposed by which selective separation can be achieved in the presence of salt ions. These mechanisms under different flotation conditions are systematically discussed in this study. Literature review reveals that two adsorption mechanisms are operating in the presence of Na+ ions and natural pH: Ion exchange and ion adsorption. In mixed feldspar systems, the mineral surface properties change due to ion exchange of counter ions on K-feldspar surface and become suitable for amine adsorption, while Na-feldspar surface is suppressed due to co-ion adsorption leading to limited amine adsorption. Similar mechanisms occur in acidic conditions with fluorine ions which increases the dispersion of particles and provides selectivity for K-feldspar by forming AlSiF-amine complexes. K-feldspar at alkaline pH with NaOH is activated with fluorine ions at the previous flotation stages and then floated with amine releasing K ions into the solution. The ion exchange/ion adsorption mechanism seems effective in alkaline as well as in natural and acidic conditions.

5

Application of mixed collectors on quartz-feldspar by fluorine-free flotation separation and their interaction mechanism : a review

Li Peiyue, Ren Zijie, Xie Enjun, Duan Shutong, Gao Huimin, Wu Jianxin, He Yuhao

Physicochemical Problems of Mineral Processing

|

2021

|

Vol. 57, iss. 4

139--156

EN

Quartz and feldspar are usually exist in symbiosis in nature, and they are difficult to be separated effectively by conventional physical methods owing to their similarities in crystal structures and surface characteristics. Flotation is the most resultful method, and especially, flotation with hydrofluoric acid (HF) is the most efficient way. Because HF may cause serious environmental and health problems, the effective and environmentally friendly separation of quartz and feldspar remains a formidable challenge. The crystal structure, surface broken bonds, surface energy, and solid–liquid interface properties of quartz and feldspar are investigated in this paper. In particular, some types of mixed cationic/anion collectors and their interaction mechanism on the quartz and feldspar surfaces with acidic, alkaline, and neutral media in the absence of fluorine are discussed, and the grade and scheme of quartz and feldspar for the practical application are illustrated. This review proposes concrete research approaches and provides perspectives for the advanced processing of quartz and feldspar in an environmentally friendly and economical way.

6

Investigations on the luminescence properties of quartz and feldspars extracted from loess in the Canterbury Plains, New Zealand South Island

Brezeanu D., Avram A., Micallef A., Cinta Pinzaru S., Timar-Gabor A.

Geochronometria

|

2021

|

Vol. 48, no.1

46--60

EN

The applicability of the single-aliquot regenerative-dose (SAR) protocol, by using the optically stimulated luminescence (OSL) signal of quartz as well as the post-infrared–infrared (pIRIR) signals of polymineral fine grains, namely pIRIR225 and pIRIR290, was assessed for dating loess in New Zealand South Island. OSL signals of quartz grains displayed low sensitivity. However, the application of repeated irradiation/bleaching cycles did not result in an increase in sensitivity; annealing in the 300–500°C temperature range generated the sensitisation of both the 110°C thermoluminescence (TL) peak as well as the OSL signal, likely by activation of yet unidentified luminescence centres. After heating, the quartz signal is comparable to that of ideal samples, but the annealing is precluding successful dating. On the other hand, feldspar infrared-stimulated signals displayed satisfactory properties, allowing estimation of ages ranging from 14 ± 1–29 ± 3 ka for the investigated deposit. It was shown that pIRIR225 and pIRIR290 methods have potential for dating loess in the South Island of New Zealand, based on the following observations: (i) Dose recovery tests were successful with recovered-to-given dose ratios with a <10% deviation from unity, (ii) constant residual values of about 4 Gy and about 10 Gy were obtained after exposures for 48 h in the case of pIRIR225 signals and 96 h in the case of pIRIR290 signals, respectively, (iii) while a slight dose-dependence of the residual was reported, and for a dose as large as 1600 Gy the residual values are ≅9 Gy and ≅19 Gy for pIRIR225 and pIRIR290 signals, respectively.

7

The Effect of Beneficiation on Some Properties of Osun State Ceramic Raw Materials

Abiolaa Oluranti Adetunji, Oke Adekola Olayinka, Omidiji Babatunde Victor, Adetan Dare Aderibigbe

Journal of Casting & Materials Engineering

|

2019

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Vol. 3, no. 3

62--66

EN

Clay, feldspar and silica sand are important industrial minerals which often need treatment commonly known as beneficiation to improve the quality of ceramic tiles produced from these materials. The different minerals, after sorting, were treated separately in distilled water, alcohol and hydrochloric acid before being crushed in a ball mill; they were then characterized using a pelletron accelerator. The results show an increased silicon content for clay, silica sand and feldspar; and reduced aluminum content for clay and silica sand but not for feldspar. Iron impurity and its oxide are also shown to reduce by over 50% in all the minerals while potassium was found to be the dominant element in feldspar among the defining elements. In conclusion, the increased quartz in the mineral will improve the hardness, density, porosity, and rigidity of ceramic tiles as well as providing support and controlling shrinkage. Furthermore, increasing the mineral quotient in feldspar will enhance its fluxing potential.

8

Purification of feldspar from colored impurities using organic acids

Vapur H., Top S., Demirci S.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 1

150--160

EN

In this study oxalic, citric, and glycolic acids were used in order to reduce Fe and Ti (colored impurities) from the slimes (-75 μm) feldspar samples using organic acids. The results showed that removal ratios of the colored impurities from the feldspar samples were 67.9% for Fe and 43.75% for Ti using oxalic acid and the agitated leaching (AL) method. The influence of main parameters (temperature, pulp density, leaching time, and acid concentration) were examined by using full the factorial design (24) ANOVA-Yates test technique. Next, the removal ratios of Fe% and Ti% in the tests were determined to be 80.44% and 45.39%, respectively. Additionally, the main parameters which were obtained from the best results of AL were optimized for the -500+75 μm feldspar sample. Finally, the microwave-assisted pressure leaching (MAPL) method was apply to determine the effect of pressure on leaching. The obtained results indicated that the optimum removal ratios obtained were 95.74% for Fe and 70.88% for Ti by using the MAPL tests with oxalic acid. Furthermore, the measured whiteness (L) values were observed to be over 90%. This is a suitable purification ratio for the ceramic and glass industry.

9

Testing feldspar luminescence dating of young archaeological heated materials using potshards from Pella (Tell Tabqat Fahl) in the Jordan valley

Al Khasawneh S., Murray A. S., Bourke S., Bonatz D.

Geochronometria

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2017

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Vol. 44, no. 1

98--110

EN

Recent developments in the use of more stable feldspar signals in the luminescence dating of sediments offer the possibility of obtaining accurate feldspar luminescence ages for ceramic artefacts; this is especially interesting in locations which do not provide suitable quartz extracts. Here we examine the application of the stable infrared stimulated luminescence signal measured at elevated temperature (in this case 290°C; pIRIR290) after stimulation at about room temperature to Levantine pottery samples. A total of 52 potsherds were collected from three superimposed iron-age units at Pella (Jordan); based on 14C dating, typology and seriation these units were deposited between 700 and 900 BCE. Sand-sized quartz extracts were unsuitable, and there was insufficient sand-sized feldspar, and so polymineral fine grains were chosen for dating. Various tests for reliability were undertaken (dose recovery, dependence of De on first stimulation temperature etc.). The pIRIR signals are weak, and 14 potsherds were rejected on this basis. Of the remainder, 3 were confidently identified as outliers. Based on those sherds for which IR signals were sufficiently intense, we use the ratio of the IR50 to pIRIR290 signals to argue that these outliers do not arise from incomplete resetting during manufacture. The ages from each layer are considerably over dispersed (typically by ~25%) but average ages for each unit are consistent with each other and with the expected age range. The average OSL age for the site is 2840 ± 220 years (n = 35), with the overall uncertainty dominated by systematic uncertainties; this average is consistent with the range of 14C ages from 970–1270 BCE reported from across the destruction horizon. We conclude that the pIRIR290 signal is delivering accurate ages, but that the variability in age from shard to shard is much greater than would be expected from known sources of uncertainty. This demonstrates the need for site ages to be based on multiple samples; individual shard ages are unlikely to be sufficiently accurate.

10

Ain Barbar Feldspar Magnetic Beneficiation

Kecir M., Zibouche M., Kecir A.

Inżynieria Mineralna

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2014

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R. 15, nr 2

131--136

EN

Though Algeria has many mineral resources which have been already developed, there are other resources that have to be valued such as feldspar. This paper deals with potassium feldspar from Ain Barbar deposit. The demand for feldspar as a raw material for the ceramic industry is continuously increasing, which implies an increase in the imports of this material. It became therefore imperative to develop the deposit in question. The ore contains essentially quartz, potassium oxide and iron with respective grades: 74.97% SiO2, 10.43% K2O and 0.60% Fe2O3. This latter is one of the principal impurities which will impart color and in turn degrade the quality of the ore. The objective of this work is to reduce the iron found in oxide form. For this purpose, we used High Gradient Magnetic Separation (HGMS), firstly by the dry process. This operation has allowed to reduce the iron content, from 0.60 to 0.40% Fe2O3, which is acceptable only for stoneware tiles paste of type “porcellenato”. To further reduce this iron oxide content, a wet HGMS has been realized on a finer grain size (-40+20μm) and allowed to obtain a product with 0.19% Fe2O3, which can be used in the sanitary ceramics industry.

PL

Chociaż Algieria posiada wiele zasobów mineralnych, które są rozwijane, istnieją inne zasoby, które muszą zostać ocenione takie jak skaleń. Artykuł ten zajmuje się skaleniem potasowym ze złoża AinBarbar. Zapotrzebowanie na skaleń jako surowiec w przemyśle ceramicznym nieprzerwanie rośnie, co skutkuje wzrostem importu tego materiału. Stało się więc koniecznym aby rozwinąć wspomniane złoże. Ruda ta zawiera zasadniczo kwarc, tlenek potasu i żelaza w następującym stopniu: 74,97% SiO2, 10,43% K2O i 0,60% Fe2O3. Ostatni z nich jest głównym zanieczyszczeniem, które wpływa na kolor oraz zmniejsza jakość rudy. Celem tej pracy jest redukcja żelaza, które znajduje się w formie tlenku. W tym celu użyto wysoko-gradientowej separacji magnetycznej (HGMS), najpierw w procesie suchym. Operacja ta pozwoliła na zmniejszenie zawartości żelaza, z 0,60 do 0,40% Fe2O3, co mogło zostać zaakceptowane jedynie dla wyrobów kamionkowych typu porcellenato. Aby dodatkowo zmniejszyć zawartość tlenku żelaza, mokra metoda HGMS została zrealizowana na próbkach o mniejszej wielkości ziarna (-40+20μm) co pozwoliło uzyskać produkt z 0,19% Fe2O3, który może zostać użyty w przemyśle ceramiki sanitarnej.

11

Beneficiation of low-grade feldspar ore using cyclojet flotation cell, conventional cell and magnetic separator

Hacifazlioglu H., Kursun I., Terzi M.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 2

381-392

EN

In order to increase the quality of feldspar ore and to obtain sellable feldspar concentrate, it is necessary to remove coloring impurities such as iron and titanium contained in it. For the removal of coloring minerals from feldspar ore the most widely used method is reverse flotation method. Reverse flotation process is generally carried out in conventional mechanical cells. In this study, it was aimed to enrich low-grade feldspar by using cyclojet flotation cell which was developed as an alternative to conventional cell. Then, experiments were performed by using conventional cell and wet magnetic separator and the results were compared with the flotation results obtained by using cyclojet cell. In experimental studies, 200 micrometer grain sized feldspar (albite) ore obtained from Muđla province at the west side of Turkey was used. It was detected that the sample was containing 0.100% Fe2O3 and 0.360% TiO2 as coloring minerals. Cyclojet cell, conventional cell and magnetic separator reduced the Fe2O3 content down to 0.010%, but TiO2 content was different in the concentrates obtained by different devices. There was almost no reduction in TiO2 content by magnetic separation method. Cyclojet cell reduced TiO2 content down to 0.030% and mechanical cell reduced TiO2 content down to 0.020%. The weights of the concentrate were detected as the highest (92.70%) in magnetic separator and as the lowest (75.40%) in cyclojet cell. Therefore, it is possible to say that cyclojet cell can compete with mechanical cell and removal of TiO2 in cyclojet cell is much better than the removal of TiO2 in magnetic separator. Generally, in the flotation process performed by using a reagent of Aero801 and Aero825 mixture in natural pH medium, both Fe2O3 and TiO2 can be removed at a rate of up to 90%, but magnetic separator can only remove Fe2O3 mineral.

12

Potencjalne zastosowania glinokrzemianów pochodzenia wulkanicznego

Mikuła J., Łach M.

Czasopismo Techniczne. Mechanika

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2012

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R. 109, z. 8-M

109--122

PL

W artykule przedstawiono współczesne możliwości zastosowań mikro- i nanocząstek tufów wulkanicznych, składających się z glinokrzemianów przestrzennych oraz szeregu faz tlenkowych i minerałów. Opisano przykłady dotychczasowych zastosowań występujących w tufach skaleni potasowych i mik oraz potencjalne możliwości aplikacyjne tych materiałów m.in. w ochronie środowiska, budownictwie, przemyśle kosmetycznym, metalurgii proszków oraz jako wypełniaczy w tworzywach sztucznych. Przedstawiono także możliwości wykorzystania tufów w stopach metali umacnianych cząstkami i dyspersyjnie. Zaprezentowano również wyniki badań struktury i wybranych właściwości tufu filipowickiego.

EN

The article presents the contemporary possibilities of applications of micro-and nano-particles of volcanic tuff consisting of alluminosilicates and a series of spatial phases and oxide minerals. Describes examples of existing uses occurring in tuffs feldspars and micas, and the potential application of these materials include in environmental protection, construction, cosmetics, powder metallurgy, and as fillers in plastics. It also provides the possibility of using tuffs in metal alloys strenghtening particles and dispersion. Also presented results of studies of the structure and properties of selected Filipowice tuff.

13

Skalenie z kraju i zagranicy

Lewicka E.

Surowce i Maszyny Budowlane

|

2011

|

nr 2

32-37

PL

Płytki ceramiczne, szkło, porcelana... Do ich wytworzenia niezbędne jest wykorzystanie surowców skaleniowych. W artykule przestawiono definicję surowców skaleniowych, opisano rozwój zapotrzebowania na surowce skaleniowe w Polsce, krajową produkcję skaleni i ich podaż ze źródeł zagranicznych.

14

Wybrane właściwości użytkowe płytek typu gres porcellanato

Gacki F.

Materiały Ceramiczne

|

2011

|

T. 63, nr 2

301-309

PL

Zaprezentowano wpływ właściwości wybranych płytek gres porcellanato na ich jakość funkcjonalną. Badania objęły analizę chemiczną, mikroskopową, SEM/EDS, XRD i termiczną, a także pomiary porowatości, gęstości, odporności na plamienie, wytrzymałości na zginanie, odporności na pękanie, twardości, ścieralności i propagacji pęknięć w płytkach gres porcellanato. Badane płytki składały się z amorficznej fazy krzemianowej, mullitu i kwarcu. W polskich płytkach w przeciwieństwie do włoskich zawartość mullitu pierwotnego jest wyższa niż mullitu wtórnego, a badania twardości ujawniły lepszą jakość krajowych produktów w porównaniu z włoskimi. Stan ten wynika z różnic w składzie surowców skaleniowych wykorzystywanych przez polskich i włoskich producentów. Pokazano, że porowatość otwarta znacząco oddziałuje na odporność na plamienie. Badania odporności na pękanie wskazują na znaczny wpływ dużych ziaren kwarcu, w których pęknięcia mają zazwyczaj charakter na wskroś ziarnowy.

EN

The impact of the properties found for the selected gres porcellanato tiles on their functional qualities is presented. The studies included chemical, microscopic, SEM/EDS, X-ray and thermal analyses as well as determinations of porosity, density, stain resistance, bending strength, fracture toughness, hardness, grindability and crack propagation in the gres porcellanato tiles. The tiles studied were composed of the amorphous aluminosilicate phase, mullite and quartz. In the Polish tiles, contrary to the Italian ones, the content of primary mullite is higher than the content of secondary one, and hardness tests have revealed better quality of domestic products in comparison with the Italian ones. Those findings result from differences in the composition of feldspar commodities used by Polish and Italian manufacturers. It has been shown that open porosity significantly affects the stain resistance. The investigations of fracture toughness indicate a substantial role of large quartz grains in which cracks are usually of the transgranular character.

15

Ocena regionalnego zapotrzebowania na wybrane surowce ceramiczne w Polsce

Lewicka E., Galos K.

Górnictwo Odkrywkowe

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2011

|

R. 52, nr 6

79-84

PL

W artykule poddano ocenie wielkość zapotrzebowania regionalnego (tj. w poszczególnych województwach) na surowce ceramiczne użytkowane do produkcji wyrobów ceramiki szlachetnej i technicznej, tj. porcelany stołowej, porcelany elektrotechnicznej, płytek ceramicznych i ceramicznych wyrobów sanitarnych. Do podstawowych surowców ceramicznych zaliczyć należy iły biało wypalające się, kaoliny oraz surowce skaleniowe. Analizie poddano krajowe i zagraniczne źródła tych surowców, a także główne zakłady będące ich użytkownikami. Ustalono szacunkowe poziomy podaży i popytu na wymienione surowce w poszczególnych województwach, co pozwoliło na ocenę znaczenia przepływów tych surowców pomiędzy poszczególnymi regionami oraz z zagranicy.

EN

The article evaluates the regional demand (i.e. in individual voivodeships) for the ceramic raw materials utilized in the production of ceramic goods such as chinaware, electrical porcelain, ceramic tiles and sanitaryware. The principal ceramic raw materials are: white firing clays, kaolin, and feldspar. Their domestic and foreign sources, as well as main plants utilizing these raw materials have been analyzed. Estimated volumes of demand and supply in particular voivodeships have been determined, what allowed for relevance of these raw materials flow among particular regions and from abroad.

16

Investigating the resetting of OSL signals in rock surfaces

Sohbati R., Murray A. S., Jain M., Buylaert J.-P., Thomsen K. J.

Geochronometria

|

2011

|

Vol. 38, no. 3

249-258

EN

There are many examples of buried rock surfaces whose age is of interest to geologists and archaeologists. Luminescence dating is a potential method which can be applied to dating such surfaces; as part of a research project which aims to develop such an approach, the degree of resetting of OSL signals in grains and slices from five different cobbles/boulders collected from a modern beach is investigated. All the rock surfaces are presumed to have been exposed to daylight for a prolonged period of time (weeks to years). Feldspar was identified as the preferred dosimeter because quartz extracts were insensitive. Dose recovery tests using solar simulator and IR diodes on both K-feldspar grains and solid slices taken from the inner parts of the rocks are discussed. Preheat plateau results using surface grains and slices show that significant thermal transfer in naturally bleached samples can be avoided by keeping preheat temperatures low. Equivalent doses from surface K-feldspar grains were highly scattered and much larger than expected (0.02 Gy to >100 Gy), while solid surface slices gave more reproducible small doses (mean = 0.17š0.02 Gy, n = 32). Neither crushing nor partial bleaching were found to be responsible for the large scattered doses from grains, nor did the inevitable contribution from Na-feldspar to the signal from solid slices explain the improved reproducibility in the slices. By modelling the increase of luminescence signal with distance into the rock surface, attenuation factors were derived for two samples. These indicate that, for instance, bleaching at a depth of 2 mm into these samples occurs at about ~28% of the rate at the surface. We conclude that it should be possible to derive meaningful burial doses of >1 Gy from such cobbles; younger samples would probably require a correction for incomplete bleaching.

17

The effect of thermal stimulation on the far-red and orange-red irsl signal of a french k-rich feldspar: preliminary results

Fattahi M.

Geochronometria

|

2009

|

Vol. 34

15-24

EN

Feldspar suffers from anomalous fading. Previous studies suggest that the level of fading depends on the emission band, and that the fading decreases by increasing the emission wavelengths; therefore, it is interesting to compare blue, orange and far-red IRSL emission characteristics. The purpose of this article is to make an initial consideration of some physical differences between two close emission windows. The effect of the sample temperature on far-red (λ >650 nm) and orangenear- red IRSL (λ =600-650 nm) from an identical feldspar sample is investigated. The difference in signal decay rate and thermal effects is discussed. While there is signal enhancement for far-red IRSL signals between 100-220° C, orange-near-red signals do not change. Some possible mechanisms for producing far-red and orange-near-red IRSL are discussed. This paper shows that orange-near-red IRSL and far-red IRSL thermal activation energies are different. This difference may be the cause of previously observed differences in stability of near and far-red IRSL signals.

18

Formy związania tlenków barwiących w surowcu skaleniowo-kwarcowym ze Sławniowic (Dolny Śląsk)

Lewicka E., Wyszomirski P.

Materiały Ceramiczne

|

2008

|

T. 60, nr 4

153-156

PL

Przedmiot badań stanowił bogaty w alkalia, częściowo zwietrzały leukogranit odsłaniający się w ścianie czynnego kamieniołomu wapieni krystalicznych w Sławniowicach k. Nysy na Dolnym Śląsku. Przydatność tej kopaliny do produkcji płytek ceramicznych gres porcellanato potwierdziły próby technologiczne przeprowadzone w warunkach przemysłowych. Dalsze badania wykazały jednak, że barierę dla jej wykorzystania w innych branżach przemysłu ceramicznego (np. do produkcji wyrobów sanitarnych) może stanowić udział związków barwiących, tj. minerałów żelaza i tytanu, które zostały rozpoznane na etapie obserwacji mikroskopowych w świetle przechodzącym. W celu ustalenia możliwości obniżenia ich udziału przeprowadzono w skali laboratoryjnej próbę wzbogacania kopaliny ze Sławniowic na drodze separacji magnetycznej i flotacji, a także badania form występowania faz żelazistych w produktach wzbogacania magnetycznego. Wobec trudności z jednoznaczną identyfikacją tych faz za pomocą metody rentgenograficznej i mikroskopii scanningowej SEM/EDS do ich rozpoznania zastosowano metodę spektroskopii mössbauerowskiej. Metoda ta umożliwiła stwierdzenie obecności żelaza związanego z jego minerałami tlenkowymi, tj. hematytem, goethytem i lepidokrokitem, a także występującego w formie podstawień diadochowych jonów Fe2+ i Fe3+ w strukturze chlorytu i illitu oraz minerałów skaleniowych. Formy występowania faz żelazistych w badanej kopalinie, zwłaszcza domieszki diadochowe w strukturze powyższych minerałów, w istotny sposób ograniczają możliwości obniżenia udziału związków barwiących w procesach wzbogacania. Surowiec skaleniowo-kwarcowy ze Sławniowic powinien jednak znaleźć zastosowanie w tych dziedzinach przemysłu ceramicznego, w których nie stawia się wybitnie ostrych wymagań dotyczących zawartości tlenków barwiących.

EN

Rich in alkalis partly weathered leucogranite occurring in the operating guarry of crystalline limestone of Sławniowice near Nysa in Lower Silesia was the object of the presented research. Suitability of this raw material for the production of gres porcellanato tiles was confirmed by the industrial-scale examinations. However, further investigations revealed, that the content of colouring oxides could be an obstacle for utilisation of this rock in other branches of ceramic industry, e.g. for the production of sanitaryware. In order to determine the possibilities of reduction of the content of Fe2O3 and TiO2, the raw material was processed using magnetic separation and froth flotation on a laboratory scale. The observations carried out by transmission microscopy showed the presence of iron and titanium minerals in the rock from Sławniowice, however exact identification of all ferruginous phases by XRD and SEM/EDS methods was rather difficult. Therefore, they were examined by the Mössbauer method. The Mössbauer spectra of these phases exhibited the occurrence of iron in its own oxide minerals, i.e. hematite, goethite, and lepidocrocite, and as substitutions of Fe2+ and Fe3+ ions in the structure of chlorite, illite, and feldspar minerals. Forms of occurring of the ferruginous phases, especially as impurities in the structure of above-mentioned minerals, seem to be the basic limitation in Iowering of the content of iron oxides in the process of beneficiation of the raw material studied. However, this rock can be successfully utilized in these branches of ceramic industry, in that the requirements referring to colouring oxides are not very strict.

19

Luminescence ages of feldspar contaminated quartz from fluvial terrace sediments

Kiyak N. G., Erturaç M. K.

Geochronometria

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2008

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Vol. 30

55-60

EN

This study focuses on obtaining luminescence ages in feldspar contaminated quartz from well-developed fluvial terraces of the Yesilirmak (Iris) river located inside the eastern North Anatolian Fault Shear Zone (NAFZ). We applied a technique based on conventional single-aliquot regenerative-dose (SAR) protocol, modified with an IR pre-treatment to reduce the OSL contribution from feldspar for accurately measuring the dose in quartz. All investigated samples showed an ability to measure a beta dose given in the laboratory, a so called dose recovery test. The dependence of the equivalent dose on thermal treatment was also examined. Dose rate calculations were based on spectral analysis of gamma measurements by a field spectrometer on site. The efforts to establish a chronology using the IR modified SAR technique produced reliable dose results in stratigraphic order. Results were reproducible and grouped broadly between 35-109 ka for Bektemur, 32-36 ka for Kizilca, 19-47 ka for Aksalur and 35-44 ka for Sahinkaya. Obtained results show that the studied area was controlled by tectonic activities within the last 50 ka and the sample Aksalur 2 was the loess deposit formed by aeolian activity.

20

Anomalous fading of IR-stimulated luminescence from feldspar minerals : some results of the study

Molodkov A., Jaek I., Vasilchenko V.

Geochronometria

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2007

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Vol. 26

11-17

EN

An increasing amount of evidence shows that the use of feldspars in luminescence dating may suffer from significant age underestimates, which are thought to result from anomalous fading. In the hope of finding a solution to the problem we undertook physical investigations of kinetics and temperature dependencies of tunnel afterglow of these minerals. As a result, the method of the direct detection of the tunnel transitions from the dosimetric traps is proposed. Some other relevant results obtained are also presented and discussed. Particularly, the probable reasons of absence of effects of anomalous fading in the feldspar samples investigated in the present work are elucidated.