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1

The selective depression effect of sodium hexametaphosphate on the separation of chlorite and specularite

Zhao Fugang, Yu Xiankun, Gao Xiangpeng, Li Mingyang, Chen Xiangxiang

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 2

art. no. 166495

EN

Flotation is the most known beneficiation method for the separation of complex and refractory iron ores. As a typical iron-containing silicates, it is difficult to separate chlorite from specularite, because of the similar surface physicochemical properties. In this study, the selective depression effect of sodium hexametaphosphate (SHMP) was conducted via the cationic micro-flotation. The surface adsorption mechanism between SHMP and the two mineral surface was explored through surface adsorption amount tests, Zeta-potential measurements, Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that SHMP could selectively depress around 90% of chlorite, while its effect on the floatability of specularite was negligible (<20% depressing). The surface adsorption amount tests, Zeta-potential measurements analysis demonstrated that SHMP selectively adsorb on chlorite surface while on the surface of specularite is feeble. The further surface adsorption analysis via FT-IR and XPS proved that SHMP selective adsorption occurred on the chlorite surface mainly by chemisorption mainly through the chelation reaction between O in the phosphate groups of SHMP molecular and metal ions on surface of chlorite.

2

Fate of swelling clay minerals during early diagenesis: a case study from Gdańsk Bay (Baltic Sea)

Kisiel Marta, Skiba Michał, Damrat Mateusz, Kuligiewicz Artur, Maj-Szeliga Katarzyna, Makiel Magdalena, Zajączkowski Marek, Salata Dorota

Annales Societatis Geologorum Poloniae

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2023

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Vol. 93, No. 3

305--322

EN

The aim of the study was to recognize the early diagenetic transformations of clay minerals likely taking place in the brackish environment of Gdańsk Bay (Baltic Sea). The Vistula River loads and sediments of the Vistula delta front and prodelta were studied. The mineral compositions of the clay fractions were determined by X-ray diffractometry. The average layer charge (LC) of the expandable interlayers was determined using the O-D vibrational spectroscopy method. The major element content of the studied clays was determined by inductively coupled plasma optical emission spectrometry. The <0.2 μm clay fraction, separated from the river sediments, contained illite-smectite mixed layered minerals, rich in high-charge, dioctahedral smectite (Ilt-Sme), illite, and kaolinite. The same clay fraction, separated from the delta-front sediments, was also composed mainly of Ilt-Sme, illite, kaolinite, and hydroxy-interlayered minerals. The <0.2 μm clay fraction from the prodelta sediments was depleted in Ilt-Sme and enriched in illite and chlorite, relative to the clays from both the river and the delta-front sediments. The LCs (0.45 to 0.56 per formula unit) were higher for clays from the river and the delta front sediments, relative to the clays from the prodelta. The <0.2 μm clay fractions from the prodelta sediments were enriched in MgO, Fe2O3, and K2O, relative to the fine clay fraction from the river. The results indicated that the smectite component of Ilt-Sme, deposited by the Vistula in Gdańsk Bay, underwent chloritization and likely illitization. The chloritization most likely proceeded via formation of hydroxy-interlayers within the smectite. Illite-like minerals, formed at the expense of the smectite with high LC, due to selective adsorption and fixation of K+ from seawater.

3

Flotation separation of cassiterite and chlorite using carboxymethyl cellulose as a depressant

Hu Yang, Ying Luo Hong, Zhang Ying, Wei Lu Kuan, Hao Guan Zhen

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 155141

EN

The nature and mechanism of interaction between carboxymethyl cellulose (CMC) with cassiterite (and chlorite surfaces) and their effects on the flotation separation process of cassiterite (from chlorite) were investigated by micro-flotation tests, surface adsorption experiments, zeta potential measurements, solution chemical calculation, infrared spectroscopy, and X-ray photo-electron spectroscopy (XPS). The results from single mineral tests revealed that CMC exhibited good selective inhibition effects with cassiterites and chlorites. When the dosage was 12.5 mg/L at pH 8, cassiterite and chlorite recovery was 92.2% and 6.3%, respectively. The artificial mixed ore test revealed that the flotation separation effect was the best when the dosage of CMC was 6.5 mg/L. Cassiterite used during the studies was 75.1% pure. The recovery was 82.8%. The interaction between CMC and the cassiterite surface led to a shift in the zeta potential toward the negative direction. CMC was weakly adsorbed on the cassiterite surface. There was no significant impact on the subsequent collection of sodium oleate. The concentration of C atom increased post interaction, and the potential shifted toward the negative direction. Characteristic CMC peaks were observed at this point. Hydrogen bonds and weak chemisorption interactions between CMC and chlorite affected the interaction between sodium oleate and the chlorite surface. It also affected the flotation results. The cassiterite and chlorite were separated effectively.

4

Dispersion of sodium phytate on muscovite and the implications for arsenopyrite flotation

Zou Dan, Wang Zhen, Zhao Kaile, Xu Ying

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 154951

EN

The effective flotation separation of sulfides and sliming silicate minerals is always a difficult problem. In this paper, the selective flotation of arsenopyrite from muscovite was studied by using sodium phytate (SP) as dispersant, and the mechanism was investigated through SEM/EDS, zeta potential, FTIR and XPS measurements. Single mineral flotation results showed that with the increasing isoamyl xanthate (IAX) dosage the recovery of arsenopyrite increased, until 8×10−5 mol/L IAX (79.40% recovery, pH=7), after that it decreased slightly. While muscovite floated poorly at any IAX concentration. For the mixed minerals, arsenopyrite recovery was only 54.63% while that of muscovite was 42.70%, which was attributed to the coverage of muscovite on arsenopyrite surface. When 6×10−5 mol/L SP was added into the mixed minerals system, the recovery of arsenopyrite recovered to 68.26% while that of muscovite was 8.48% (approximate the value of the single mineral). SEM/EDS results showed that SP could disperse muscovite and prevented its coverage on arsenopyrite surface. Zeta potential results showed that the electrokinetic potential of muscovite and arsenopyrite decrease from -26.60mV to -39.01 mV and from -26.90 mV to -27.84 mV at pH=7, respectively. It was obvious that the negatively charged phytate ions selectively adsorbed on the surface of muscovite. FTIR and XPS resulted co-proved the chemisorption of SP with active sites on muscovite while arsenopyrite spectrum did not change significantly, which was consistent with flotation and zeta potential results. The selective adsorption of SP on muscovite compared to arsenopyrite was responsible for the effective separation of them.

5

Mineralogy and organic geochemistry of phyllite from the Dewon-Pokrzywna deposit, the Opava Mountains (SW Poland)

Sawicka N., Janeczek J., Fabiańska M., Bahranowski K., Krzykawski T., Matuszewska A.

Geological Quarterly

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2018

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Vol. 62, No. 4

817--828

EN

Phyllites from the Dewon-Pokrzywna deposit in the Opava Mts., SW Poland, were investigated by XRD (Rietveld method), XRF, EPMA, SEM, and ATR-FTIR from the perspective of their potential usage as a buffer and/or backfill material in a geological repository of radioactive waste. Organic matter dispersed in the phyllite matrix was analysed by GC-MS. Fine-grained Mg-Fe-muscovite (13 to 29 wt.%), Fe-ripidolite (10 to 25 wt.%), detrital quartz (20 to 46 wt.%), and albite (7 to 28 wt.%) ± microcline, illite or illite/smectite, and kaolinite are major minerals in phyllite samples. The chlorite/muscovite ratio ranges from 0.65 to 1.1. Mg-annite inherited from the precursor rock is a minor constituent. Detrital ilmenite is a dominant accessory mineral. Ancylite-(Ce) occurs in quartz-calcite-ripidolite veins. Two types of phyllite have been distinguished based on the proportion of phyllosilicates to silt fraction: argillaceous (47 to 55 wt.% phyllosilicates) and silt-rich (28 wt.% phyllosilicates). Argillaceous phyllite shows elevated content of alumina and moderate concentration of silica. It is highly enriched in Fe compared to phyllites from other localities worldwide. The BET specific surface area of argillaceous phyllite ranges from 1.73 to 3.64 m2/g. Whole-rock chemical composition, mineral assemblages, chlorite geothermometry, and the occurrence of aliphatic hydrocarbons suggest that argillaceous phyllite originated from a pelagic pelite protolith under low-temperature (260-370°C) greenschist to subgreenschist facies conditions. Persistent biomarkers are indicative of bacterial degradation of planktonic organic matter suspended in a high water column. Enrichment in Fe-rich chlorite and Mg,Fe-muscovite, low volume of interconnected pores with dominant mesopores suggest that argillaceous phyllite from the Dewon-Pokrzywna deposit is a potential candidate for a buffer and/or backfill material.

6

Phase change of chlorite in reducing atmosphere

Liu X., Yu Y., Chen W., Liu X.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 2

607--614

EN

Magnetizing roasting is an important pre-treatment technique for beneficiation of hematite and limonite ores. Reduction mechanisms of these iron minerals have been fully studied while the mechanism of reduction of chlorite is not well understood. In this study, a reduction roasting study examining the phase change of chlorite with roasting temperature was undertaken. The major finding from this study was that chlorite partially was reduced to magnetite by carbon at 750 ⁰C, and the newly formed magnetite was finely disseminated within quartz and olivine. It was demonstrated that these locked magnetite particles would be reported to iron concentrate by low intensity magnetic separation resulting in high impurity content, especially SiO2 and Al2O3 contents in the concentrate.

7

Uboczne nieorganiczne produkty dezynfekcji wody. Problemy i wyzwania

Michalski R, Łyko A

Inżynieria i Ochrona Środowiska

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2012

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T. 15, nr 4

353--364

PL

Uzdatnianie wody w procesach dezynfekcji jest uważane za główne osiągnięcie w zakresie zdrowia publicznego w XX wieku. W latach 1970 stwierdzono, że chlorowanie wody do spożycia powoduje wytwarzanie niebezpiecznych dla zdrowia związków organicznych, takich jak trihalometany. Później stwierdzono obecność w chlorowanej wodzie ponad 500 takich ubocznych produktów dezynfekcji. Wkrótce rozpoczęto poszukiwanie alternatywnych do chlorowania metod dezynfekcji wody przeznaczonej do spożycia. Interesującą alternatywą okazało się być zastosowanie ozonu i ditlenku chloru. Niestety metody te poza wieloma zaletami charakteryzują się powstawaniem nieorganicznych produktów ubocznych, takich jak chlorany(III), chlorany(V) i bromiany(V). Ozonowanie wody zawierającej bromki powoduje powstawanie rakotwórczych bromianów(V). Z kolei chlorany(III) i chlorany(V) powstają, gdy stosuje się ditlenek chloru. Najpopularniejszą instrumentalną metodą oznaczania jonów jest chromatografia jonowa, która zastąpiła większość dotychczas stosowanych metod mokrych. Metody oznaczania jonów ClO2-, ClO3- i BrO3- oparte na chromatografii jonowej można podzielić na metody bezpośrednie, pośrednie oraz techniki łączone. Wybór odpowiedniej metody zależy od oczekiwanych granic oznaczalności, możliwości technicznych laboratorium oraz liczby i rodzaju próbek do analizy. W pracy przedstawiono warunki tworzenia się poszczególnych nieorganicznych produktów dezynfekcji wody, metody ich oznaczania oraz regulacje prawne związane z ich obecnością w wodach.

EN

Water treatment by disinfection processes is considered a major public health achievement of the twentieth century. In the 1970s, it was discovered that chlorination of drinking water produces carcinogens, such as trihalomethanes. Since 1974, the presence of more than 500 disinfection by-products has been determined in drinking water. Since that time, environmental regulatory agencies as well as drinking water treatment technologists have been carrying out extensive research for alternative disinfection methods that minimize the generation of byproducts posing significant health risks. Another disinfection process which has emerged as the most promising alternative to chlorination technique is using of ozone or chlorine dioxide. In spite of undeniable advantages, there are certain undefined hazards resulting from this method of water treatment. Main hazardous inorganic oxyhalide disinfection by-products are: bromate, chlorite and chlorate. The ozonation of water containing bromide can cause the formation of bromate. Chlorite is formed when chlorine dioxide is used, whereas chlorate is formed when chlorine, chlorine dioxide, hypochlorite or chloramine is used to disinfect raw water. Bromate has been identified as animal and possible human carcinogen. International Agency for Research on Cancer (IARC) classified bromate into group B-2 as the agent is possibly carcinogenic to humans. The United States Environmental Protection Agency, as well as the Commission of the European Communities have issued rules that require public water supplies to control previously unregulated microorganisms and cancer-causing disinfection by-products in finally treated drinking water. According to these regulations Maximum Admissible Level (MAL) is 10 μg/dm3 for bromate and 1000 μg/dm3 for chlorite. Recently the commonly used analytical method for the determination of inorganic anions and cations is ion chromatography, which has almost replaced most of the wet chemical methods used in water and waste water analyses. The methods of chlorite, chlorate and bromate determination employing ion chromatography can be generally divided into: 1. Direct methods (suppressed conductivity detection). 2. Indirect methods (UV/Vis detection after post-column derivatization). 3. Hyphenated techniques (ICP-MS and MS detection). All the three groups of recently developed ion chromatography methods yield comparable results and comply with the requirements of the international directives concerning inorganic oxyhalide by-products in drinking water. The future application and choice of a method will depend on the equipment available in laboratories, as well as the number and kinds of samples to be analyzed. The paper presents the formation, determination and legal regulation of these inorganic oxyhalides disinfection by-products in drinking water.

8

Chlorite of hydrothermal origin formed in the Strzelin and Borów granites (Fore-Sudetic Block, Poland)

Ciesielczuk J. M.

Geological Quarterly

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2012

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Vol. 56, No 2

333-344

EN

Chlorite, a product of very low- to low-grade metamorphism, is frequently used as a geothermometer because of the fact that its structure and chemical composition can reflect the physical and chemical conditions of its formation. In the hydrothermally altered Strzelin and Borów granites (the Fore-Sudetic Block, Poland) chlorite is ubiquitous. It is found in two forms: spherulitic and post-biotite, and was formed in different ways in different parts of the Strzelin and Borów granites: as result of (1) replacement of biotite or (2) crystallisation from fluid. The chlorite formed in the Borów granite shows a higher Fe content than that in the Strzelin granite, a feature related to the content of Mg and Fe in the host rock. Temperatures of chlorite formation are the lowest for unaltered granite and then gradually increase for slightly, moderately and strongly altered granite and are the highest in hydrothermal veins. This means that the temperature of the hydrothermal fluid was higher than that of the altered granitic bodies. Moreover, the spherulitic chlorite formed at a higher temperature than did the post-biotite chlorite, and is usually smaller because biotite replacement lasted longer than did the crystallisation of spherulitic chlorite directly from hydrothermal fluid. Such pattern are likely to occur in other granitic bodies.

9

Clay minerals as palaeoenvironmental indicators in the Bathonian (Middle Jurassic) ore-bearing clays from Gnaszyn, Kraków-Silesia Homocline

Dudek T.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

297-305

EN

This paper reports the results of X-ray diffraction quantitative mineralogical studies of the clay-rich Middle Jurassic sedimentary rocks from Gnaszyn, central Poland and their palaeoenvironmental interpretation. The palaeoenvironmental interpretation is aided by the fact that the sediments have not been significantly altered by diagenesis. The mineral composition is uniform throughout the succession: quartz, K-feldspar, plagioclase, calcite, gypsum, anhydrite, pyrite, illite, kaolinite, chlorite, and glauconite. The clay assemblage is dominated by illite, which alone accounts for about 20 wt% of the total mineral content. Kaolinite amounts usually <10 wt% and chlorite and glauconite occur in subordinate quantities. The clay mineral assemblage is largely of detrital origin and indicates rather cool and/or dry climatic conditions favouring mechanical erosion of the source rocks.

10

Dry magnetic separation of olivine sand

Kleiv R. A., Thornhill M.

Physicochemical Problems of Mineral Processing

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2011

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Vol. 47

213-228

EN

This paper investigates the potential for using dry magnetic separation to reduce the chromium content of a dried high quality olivine sand product in order to meet with anticipated future quality demands. The original feed contained 0.28-0.29% Cr2O3 of which approximately one third occurred as chromite and two thirds as chlorite. Two stage Permroll separation (at 0.50 T (max) and 0.92 T (max)) produced a concentrated product containing 0.13% Cr2O3 at a product recovery of 85.28%, thus reducing the chromium content by 55%. Some 80% of this reduction was achieved as a result of the first separation stage where chromite reported to the magnetic tailings at a recovery close to 100%. The chromium remaining in the concentrated product must be attributed to chlorite. Leachates obtained from leaching tests performed on the feed and the products were characterised by very low chromium concentrations, and the results suggest that chromium is more easily released from chlorite than chromite. This study shows that dry magnetic separation could be considered when a reduction of the chromium content of dried high quality olivine sand products is required.

11

Observations on the effect of proximity to rhyolitic intrusions on Kübler index

Diskin S., Coetzee S. H.

Mineralogia

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2010

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Vol. 41, iss. 1/2

75--94

EN

The Upper Ordovician sedimentary succession of southeast Ireland is riddled with almost synsedimentary igneous intrusions. A study was required to determine any effects of these intrusions on Kübler Index (KI) so that further sampling for a regional study could be undertaken and the results would be unbiased. Sampling was carried out on the low-grade metapelites (Southeast Ireland) around the rhyolitic and doleritic intrusions, which were intruded into the still soft sediment. Clay mineralogy was determined using X-ray diffractometry and KI values were measured; SEM and whole rock elemental analyses were applied to complement the results of the XRD work. KIs immediately around rhyolitic intrusions were observed in all cases to be lower than the regional KI, however this was not seen around doleritic intrusions. SEM work shows illite grain sizes following the KI trend and K2O were noted to be highest where KI was lowest. Rare earth elements (REEs) show some mobilization which also follows the KI trend. This is considered to be a residual effect of hydrothermal fluids / volatiles hosted by the rhyolites but not encountered in the dolerites. Chlorite crystallinity is not affected as it most likely crystallized after the hydrothermal event. The KI is often used as a proxy for illite crystallinity in studies of low grade metamorphism but is influenced by many parameters and care should be taken when applying this technique to studies of regional metamorphism.

12

A flow method with spectrophotometric detection for determination of chlorite ions in drinking water

Herman M., Kościelniak P., Wieczorek M., Stafiński M., Matuszek M.

Chemia Analityczna

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2009

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Vol. 54, No. 6

1383-1395

EN

The paper presents a newly developed flow method with spectrophotometric detection for determination of ehlorites in drinking water. The method is based on reaction of chlorite ions with iron(II0 in an acidic environment. The analytical signal was measured for the coloured l;e(II)/o-phenanthroline complex at 512 nm. Determinations were carried out using a How system. Validation studies revealed that the method is linear in the analyte's concentration range 0.1-6.0 mg L-1 and assures determination precision RSD < 0.40%. Limit of detection and limit of quantification were estimated as 0.01 and 0.03 mg L-1,respectively. The interferences caused by different ions were studied taking into consideration their concentrations ranges occurring in water classified into four quality classes.The method was applied to the analysis of water samples taken from different intakesin Krakow (Poland) and the analytical results were compared with those obtained by ionchromatography method.

PL

W pracy przedstawiono metodę przepływową z detekcją spektrofotometryczną do oznaczania chloranów(III) w wodzie pitnej. Podstawą metody jest reakcja jonów chloranowych(III) z jonami Fe(Il) w środowisku kwaśnym i pomiar sygnału analitycznego dla barwnego kompleksu jonów Fe( II) z o-fenantrolinąprzy długości fali 512 nm. Oznaczenia wykonywano przy użyciu zestawu do analizy przepływowej. Badania walidacyjne wykazały, że metoda charakteryzuje siei iniowością w zakresie stężenia 0.1-6.0 mg L-1pozwalając na oznaczenia analitu z precyzja, (RSD) < 0.40%. Granice wykrywalności i oznaczalności analitu wynosiły odpowiednio 0.01 i 0.03 mg L1. Zbadano interferencje wywołane występowaniem różnych jonów w zakresach stężeń typowych dla wód o czterech klasach czystości. Metodę zastosowano do analizy próbek wód pobranych z różnych ujęć na terenie Krakowa. Otrzymane wyniki analityczne porównano z rezultatami otrzymanymi metodą chromatografii jonowej.

13

57Fe Mössbauer study of stilpnomelane and associated chlorite from Polish granite pegmatites

Malczewski D., Popiel E., Sitarek A.

Nukleonika

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2004

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Vol. 49,suppl.3

43-48

EN

This paper reports the results of 57Fe Mössbauer study of stilpnomelane K0.6Fe6(Si8Al)(O,OH)27 .2H2O from Żółkiewka (Lower Silesia, Poland). Stilpnomelane in paragenesis with chlorite, tourmaline, claevelandite and zeolites has been found in granite pegmatites in quarries at Żółkiewka. The samples of naturally weathered stilpnomelane and chlorite from the same fragment of rock were also studied. The Mössbauer spectrum of an untreated sample could be fitted to two Fe2+ doublets and two Fe3+ doublets. The Fe2+ doublets have similar isomer shifts, but they distinctly differ in values of quadrupole splittings. Ferric iron, octahedrally coordinated occurs in three different environments represented by two doublets. The first of them, assigned to combined M1 + M2 positions and the second one assigned to M3 site with parameters IS = 0.36 mm/s and QS = 2.07 mm/s is visible in the spectra up to 880°C. This doublet is characteristic of stilpnomelane and can be regarded as a "fingerprint" of this mineral. After heating at 200°C, the relative content of Fe2+, ÓFe2+/ÓFe, decreases to 0.22 what means a 50% decrease in comparison to the initial value observed in the untreated sample. At about 1000°C, complete breakdown of the stilpnomelane structure takes place and the Mössbauer spectrum consists of two sextets and two ferric doublets. Abnormally high content of Fe2+ in naturally weathered stilpnomelane (0.70) comparing to the untreated sample of stilpnomelane (0.45) indicates that the sample had to be subjected to hydrothermal processes operating locally. Almost the same contents of divalent iron and hyperfine parameters of Fe2+ and Fe3+ doublets in weathered stilpnomelane and associated chlorite suggest that the process of chlorite transformation into stilpnomelane seems to be very probable.

14

Nieorganiczne utlenione halogenopochodne uboczne produkty dezynfekcji w wodach do picia - powstawanie, oznaczanie, regulacje prawne

Michalski R.

Ekologia i Technika

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2004

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R. 12, nr 2

40-49

PL

Ochrona ludzi przed potencjalnymi niebezpiecznymi dla zdrowia mikroorganizmami obecnymi w wodach do picia, wymaga jej regularnej dezynfekcji różnymi metodami. Dezynfekcja taka przeprowadzana jest zazwyczaj za pomocą chloru. Jest to dobrze znana i efektywna technologia, posiadająca wiele zalet, jakkolwiek podczas jej stosowania tworzą się niebezpieczne dla zdrowia produkty uboczne takie jak min. trihalometany. Alternatywną wobec chlorowania metodą uzdatniania wód jest stosowanie ozonu lub ditlenku chloru. Pomimo niezaprzeczalnych zalet tych nowych metod, posiadają one również pewne wady. Dotyczą one głównie tworzenia się utlenionych nieorganicznych halogenopochodnych takich jak: bromiany, chloryny i chlorany. Niektóre z nich są zakwalifikowane jako substancje prawdopodobnie rakotwórcze dla ludzi. Bromiany mogą powstawać w wodach surowych zawierających bromki poddawanych procesom ozonowania. Stosowanie ditlenku chloru może powodować tworzenie się w nich chloranów i chlorynów. Niniejszy artykuł dotyczy powstawania, oznaczania oraz regulacji prawnych w zakresie ww. nieorganicznych utlenionych halogenopochodnych ubocznych produktów dezynfekcji wód do picia.

EN

In an effort the public from potentially hazardous microorganisms, drinking water supplies are routinely disinfected with a variety of treatment methods. Disinfections of drinking water are usually carried out by chlorination process. This is a well known, effective technology which has many advantages, however during this process dangerous for health by-products, such as trihalomethanes are formed. Another disinfection process which has emerged as the most promising alternative to chlorination technique is using of ozone or chlorine dioxide. In spite of undeniable advantages, there are certain undefined hazards resulting from this method of water treatment. It is especially due to formation of inorganic oxyhalide by-products such as bromate, chlorite and chlorate. Some of them have been classified as probable human carcinogen. Bromate can be form when source waters containing bromide are disinfected with ozone. The use of chlorine dioxide can cause formation of chlorite and chlorate. The paper presents the formation, determination and legal regulation of these inorganic oxyhalides disinfection by-products in drinking water.

15

Zapotrzebowanie na dwutlenek chloru w uzdatnianiu wód infiltracyjnych

Maćkiewicz J., Dziubek A., Czarniecka J.

Ochrona Środowiska

|

2003

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R. 25, nr 1

9-12

PL

Określono zapotrzebowanie na dwutlenek chloru dla wody infiltracyjnej oczyszczonej w układach technologicznych obejmujących procesy napowietrzania i filtracji oraz napowietrzania, filtracji i sorpcji. Analizowano wpływ stężenia ogólnego węgla organicznego na dawkę dwutlenku chloru, a także zmienność niektórych wskaźników jakości wody. Stwierdzono, że wskutek działania utleniającego zastosowanego dezynfektanta w wodzie pojawiają się uboczne produkty utleniania, których stężenie malało, gdy w wodzie pozostawał wolny dwutlenek chloru. Stwierdzono także, że stosowanie dwutlenku chloru, poza działaniem dezynfekcyjnym, spowodowało obniżenie intensywności barwy i zawartości OWO w uzdatnianej wodzie. Wykazano, że dawka pokrywająca zapotrzebowanie wody na dwutlenek chloru wyraźnie zależała od początkowego stężenia OWO i była zawsze większa od dawki dezynfekcyjnej.

EN

Chlorine dioxide demand was determined in infiltration water after treatment by aeration and filtration or by aeration-filtration-sorption. The effect of TOC concentration on the chlorine dioxide dose, as well as the variability of some water quality parameters, was examined in more detail. It was found that the oxidizing activity of the disinfectant in the water accounted for the formation of some oxidation by-products and that their concentration decreased when free chlorine dioxide persisted in the water. The study also showed that chlorine dioxide not only acted as a disinfectant but also contributed to the reduction of coloured matter and TOC in the treated water. As it can be inferred from the analysis of the results obtained, the dose covering the chlorine dioxide demand in infiltration water depended noticeably on the initial TOC concentration and was higher than the disinfecting dose.

16

Layer silicates from Szklary (Lower Silesia): from ocean floor metamorhism to continental chemical weathering

Dublińska E., Sakharov B.A., Kaproń G., Bylina P., Kozubowski J.A.

Geologia Sudetica

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2000

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Vol. 33, nr 2

85-105

EN

The weathering crust at Szklary is known as a classical location of a nickeliferous laterite deposit derived from the chemical weathering of ultrabasic rocks. The layer silicates from the Szklary massif have been studied since the eighteenth century; moreover, this locality is considered to be an exceptional location of different minerals including nickel containing corrensite, interstratified kerolite-stevensite, interstratified serpentine-smectite, kerolite-pimelite, and clintonite. Ni-corrensite and irregularly mixed-layer serpentine-smectites with a variable layer ratio were found in Szklary for the first time. The origin of the layer silicates from Szklary is complex: (1) serpentine, chlorite, and clintonite are products of hydrothermal metamorphism related to the serpentinization of ultramafic rocks and posterior metamorphism and (2) the mixed-layer minerals, sepiolite, and kerolite-pimelite formed due to the hydrothermal and supergeneous alteration of ultrabasic rocks and various metamorphic schists.

17

Chloritisation of hornblende and biotite : a HRTEM study

Ferrow E., Bagiński B.

Acta Geologica Polonica

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1998

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Vol. 48, no. 1

107-113

EN

The coarse textures produced by hydration of hornblende and biotite during retrograde metamorphism of the rocks of the K?odzko-Z?oty Stok area were identified easily by both optical microscopy and scanning electron microscopy (SEM). However, the micro-textures that are a few unit cell in dimensions were identified through high resolution transmission electron microscopy (HRTEM) only. For the alteration of biotite to chlorite the replacement of potassium in the interlayer by a brucite-like layer and the subsequent increase in volume was observed. There were, however, some missing brucite-like layers within the chlorite units. Moreover, both topotactic and low angle replacement of biotite to chlorite were identified. For the direct hydration of hornblende to chlorite, HRTEM and selected area electron diffraction pattern (SAED) showed that the c* and a* of chlorite were parallel to the b* and a* of hornblende, respectively. Nevertheless, other orientation relationships were also observed by optical microscopy.