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1

Synthesis and solubility of hopeite Zn3(PO4)2·4H2O

Bajda Tomasz, Rogowska Melania, Pawłowska Agnieszka

Mineralogia

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2023

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Vol. 54, iss. 1

78--81

EN

Minerals from the phosphate groups are used in environmental engineering as thermodynamically stable vehicles for heavy metals such as zinc. The hopeite Zn3(PO4)2·4H2O was synthesized and characterized by X-ray diffraction and scanning electron microscopy. The solubility of the hopeite was measured at 25°C. The average solubility product, log Ksp, for the reaction Zn3(PO4)2·4H2O ⇔ 3Zn2+ + 2PO4 3− + 4H2O at 25°C is –35.72 ± 0.03. The free energy of formation, ΔG°f ,298, calculated from this measured solubility product is –3597.4 ± 1.0 kJ mol−1. The immobilization of zinc in the hopeite structure offers the possibility of developing an effective method for removing Zn from wastewater, water and soils.

2

Corrosion of carbonate speleothems by an allogenic river inferred from petrography and a weight loss experiment : a case study from the Demänová Cave System, Slovakia

Sala Przemysław, Bella Paweł

Annales Societatis Geologorum Poloniae

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2023

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Vol. 93, No. 4

467--481

EN

The crystallization of speleothems can be interrupted by the invasion of allogenic water into cave passages. These interruptions were studied, both in speleothems currently submerged in an underground river and in speleothem sections, which were found at the lowermost fluvially active passage level of the Demänová Cave System. The interaction between speleothems and allogenic water, undersaturated with respect to calcite, is manifested in the presence of siliciclastic material and the corrosion of calcite crystals. The progressive development of corrosion features depends on the duration of the interaction of calcite crystals with allogenic water. Moreover, the movement of the water and siliciclastic deposition over the speleothems can influence the corrosion process. The estimated rate of corrosion, caused by the underground Demänovka River and measured by the weight loss of experimental tablets, is up to 0.029 mm/y. U-series dating indicated that the interaction of speleothems with allogenic water occurred during the Vistulian (Weichselian). The identification of corrosion episodes, caused by allogenic water, is a step towards understanding the origin of hiatuses and establishing criteria for recognition of them.

3

Wybrane zagadnienia biomineralogii

Pawlikowski Maciej

Przegląd Geologiczny

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2022

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Vol. 70, nr 11

834--839

EN

Biomineralogy is the science between mineralogy, biology, medicine and biochemistry. It is focused on problems concerning mineralization of tissue and organs of human, animals and flora. It concerns interaction between mineral and biological tissue, as well as between biochemical components of living organism. These processes are important for good functioning of organs and human life.

4

Interakcja wodoru ze skałą zbiornikową

Cicha-Szot Renata, Leśniak Grzegorz

Nafta-Gaz

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2022

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R. 78, nr 8

580--588

PL

Istnieje szereg metod magazynowania wodoru, do których zaliczyć można stosowanie zbiorników napowierzchniowych, wiązanie w wodorkach metali, nanorurkach węglowych, sieciach metaloorganicznych, ciekłych organicznych nośnikach wodoru czy adsorbentach. Jednak to podziemne magazynowanie wodoru w strukturach geologicznych (PMW) wydaje się kluczowe dla rozwiązania problemu długoterminowego magazynowania dużych ilości energii oraz zwiększenia stabilności sieci energetycznej i poprawy wydajności systemów energetycznych. Kryteria wyboru struktury do magazynowania wodoru obejmują szereg czynników technicznych, ekonomicznych, ekologicznych i społecznych. Jednym z najmniej rozpoznanych obszarów badawczych dotyczących PMW jest utrata wodoru in situ wywołana reakcjami geochemicznymi, które mogą wpływać na parametry petrofizyczne oraz wytrzymałość skał uszczelniających. W artykule przeanalizowano reakcje, jakie mogą wystąpić podczas magazynowania wodoru w strukturach geologicznych. Na podstawie studium literaturowego wskazano grupy minerałów, które mogą wpływać na zmiany pojemności magazynowej oraz na czystość gazu. Należą do nich w szczególności węglany, anhydryt, ankeryt i piryt, które stanowiąc skład matrycy skalnej lub cementu, mogą znacząco wpływać na potencjał magazynowy analizowanej struktury. Podczas kontaktu z wodorem minerały te ulegają rozpuszczeniu, w wyniku czego uwalniane są m.in. jony Fe2+, Mg2+, Ca2+, SO4 2−, HCO3 − , CO3 2−, HS− . Jony te wchodzą nie tylko w skład minerałów wtórnych, ale również na skutek dalszych reakcji z wodorem zanieczyszczają magazynowany nośnik energii domieszkami CH4, H2S i CO2, co ogranicza możliwości dalszego wykorzystania wodoru. Zwrócono również uwagę na możliwość wystąpienia rozpuszczania kwarcu, którego szybkość zależy od stężenia jonów Na+ w solance złożowej oraz pH. Ponadto pH wpływa na reaktywność wodoru i zależy w dużej mierze od temperatury i ciśnienia, które w trakcie pracy magazynu będzie podlegało częstym cyklicznym zmianom. W artykule omówiono wpływ warunków termobarycznych na analizowany proces, co powinno stanowić podstawę do szczegółowej analizy oddziaływania skała–wodór– solanka dla potencjalnej podziemnej struktury magazynowej.

EN

There are several hydrogen storage methods, including surface tanks, metal hydrides, carbon nanotubes, organometallic networks, liquid organic hydrogen carriers, or adsorbents. However, underground hydrogen storage (UHS) appears to be crucial in solving the problem of long-term storage of large amounts of energy, increasing the power grid's stability and improving energy systems' efficiency. The criteria for selecting a hydrogen storage structure include a number of technical, economic, ecological, and social factors. One of the least recognized research areas concerning UHS is the in situ loss of hydrogen caused by geochemical reactions that may affect sealing rocks' petrophysical parameters and strength. The article presents the reactions that may occur during hydrogen storage in geological structures. Based on a literature study, groups of minerals that may affect changes in storage capacity and gas purity have been indicated. These include, in particular, carbonates, anhydrite, ankerite, and pyrite in both the rock matrix and the cement. Upon contact with hydrogen, these minerals dissolve, releasing, among others, Fe2+, Mg2+, Ca2+, SO4 2– , HCO3 – , CO3 2– , HS– ions. These ions are not only components of secondary minerals but also, as a result of further reactions with hydrogen, pollute the stored energy carrier with admixtures of CH4, H2S and CO2, which limits the possibilities of further hydrogen use. The possibility of quartz dissolution, the rate of which depends on the concentration of Na+ ions in the reservoir brine and the pH, was also noted. Moreover, pH influences the reactivity of hydrogen and depends mainly on temperature and pressure, which will be subject to frequent cyclical changes during the operation of the storage. This review paper discusses the influence of thermobaric conditions on the analyzed process, what should be a base for detailed analysis of the rock-hydrogen-brine interaction for the potential underground storage structure.

5

Regeneracja warstw aluminidkowych na podłożu nadstopów niklu stosowanych na łopatki silników lotniczych

Kwolek Przemysław, Góral Marek, Poznańska Anna, Wierzbińska Małgorzata, Ochał Kamil

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2019

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z. 91 [299], nr 1-2

53--65

PL

W artykule przedstawiono wybrane metody usuwania dyfuzyjnych warstw aluminidkowych stosowanych do ochrony powierzchni łopatek turbin silników lotniczych przed oddziaływaniem korozji wysokotemperaturowej. Scharakteryzowano opracowane dotychczas chemiczne i elektrochemiczne metody rozpuszczania warstw aluminidkowych. Na podstawie analizy danych literaturowych wytypowano 3 roztwory: kwasu siarkowego(VI) o stężeniu 25% mas., mieszaninę stężonego kwasu solnego (40% obj.) i etanolu (60% obj.) oraz mieszaninę stężonych kwasów ortofosforowego (50% obj.), octowego (25% obj.), azotowego (25% obj.). Przeprowadzono badania kinetyki rozpuszczania modelowej warstwy aluminidkowej modyfikowanej cyrkonem na podłożu stopu Inconel 100. Wykazano, że niezależnie od zastosowanych roztworów, rozpuszczanie następuje równomiernie na powierzchni warstwy. Stwierdzono, że największą skutecznością w usuwaniu warstw cechowała się mieszanina kwasów: ortofosforowego, octowego i azotowego, w której rozpuszczenie warstwy aluminidkowej następowało po ok. 80 min.

EN

Selected methods of removing diffusion alluminide coating used for protection of turbine blades were presented in the article. The chemical and electrochemical methods of coatings dissolution used in aerospace industry were described. Three selected removing agents were selected for experimental tests: hydrochloric acid in ethanol solution, sulphuric acid in water as well as mixture of orthophosphoric, acetic and nitride acids. The aluminide coating obtained on IN-100 nickel superalloy was used for tests. The conducted research showed that the mixture of orthophosphoric, acetic and nitride acids can dissolve outer-zone of aluminidce coating during 80 min dissolution process. The removing process takes place evenly on the whole surface of sample.

6

Study of the reaction between dolomite and nitric acid

Pultar Martin, Vidensky Jan, Sedlarova Ivona

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 2

370--379

EN

This paper is focused on the kinetics of the reaction between natural dolomite and diluted solutions of nitric acid at various temperatures. All experiments were carried out in a semi-batch reactor with an approximately constant nitric acid concentration using the pH-stat titration method. The reaction was studied in the temperature range from 293 to 353 K and the nitric acid concentration in the range from 0.001 to 0.200 mol dm-3. The strong effects of both temperature and nitric acid concentration were observed. The determined fractional values of the apparent reaction order (0.39 to 0.75) indicate a very complex reaction mechanism. In the studied concentration range, the values of the apparent activation energy increase from 30 to 58 kJ mol-1. Based on these data it can be assumed that the reaction takes place in the transitional regime with the stronger influence of chemical reaction. This assumption was verified by calculation of the nitric acid concentration on the surface of the dolomite grain using Sherwood criterion equation. The change in the role of the rate-controlling step was found for highly diluted solutions (< 0.010 mol dm-3 HNO3).

7

Dissolution kinetics of malachite in ethylene diamine phosphate solutions

Shen Peilun, Liu Ruizeng, Liu Dianwen, Zhan Xiaolin, Jia Xiaodong, Song Kaiwei

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 4

1039--1048

EN

Ethylene diamine phosphate (EDP), as a synthetic organic reagent, was used for the first time to leach malachite, and a new method of using organic amine to leach copper oxide ore was developed. The effects of stirring speed, particle size, reagent concentration, and reaction temperature on EDP-dissolution malachite were investigated. Results showed that malachite rapidly dissolved in EDP solution. The malachite-dissolving rate also increased with increased reagent concentration, increased reaction temperature, and decreased particle size. Stirring speed exhibited nearly no effect on EDP-induced malachite dissolution. The leaching kinetics was found to follow the shrinking-core model, and dissolution was controlled by surface chemical reaction with an activation energy of 52.63kJ×mol−1. A semiempirical rate equation was obtained to describe the dissolution process expressed as 1-(1-XCu)1/3=0.0149(CEDP)0.7814 × (Pmalachite)−0.7982×exp(−6.3308/T) ×t.

8

Dissolution kinetics of hemimorphite in methane sulfonic acid

Zhang Qian, Wen Shuming, Feng Qicheng, Nie Wenlin, Wu Dandan

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

1--9

EN

Hemimorphite has a large content of zinc, but its recovery using flotation alone is low. Nowadays, hydrometallurgical and pyrometallurgical methods are used to treat zinc ores. In this work, the leaching and dissolution kinetics of hemimorphite by using methane sulfonic acid (MSA) as an alternative leaching reagent was investigated. The effects of several experimental parameters including reaction temperature, MSA concentration, particle size, and stirring speed were also analyzed. Results showed that zinc leaching increased with increased reaction temperature, MSA concentration, and stirring speed, as well as decreased particle size. The mechanism of hemimorphite dissolution in MSA solutions may be a new variant of the shrinking-core model. Based on experimental data and kinetics, the apparent activation energy was determined to be 49.50 kJ/mol. The rate of reaction equation was also obtained to describe the process and found that the MSA concentration largely influenced the leaching of hemimorphite.

9

Time constraints on experimental studies of lead apatites

Topolska Justyna, Bajda Tomasz, Puzio Bartosz, Manecki Maciej, Kozub-Budzyń Gabriela

Geological Quarterly

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2019

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Vol. 63, No. 4

721--728

EN

The paper presents the results of experimental studies on the synthesis and thermodynamic stability of selected Pb-apatites in terms of criteria determining termination of the experiments. Based on the case study, we indicate difficulties in analysing the obtained experimental data. Time-resolved sampling of precipitate formed during a dropwise synthesis of pyromorphite was performed and the results were compared to the literature data. It has been concluded that the Ostwald ripening time for synthesized solids depends primarily on the chemical composition of the intended Pb-apatite phase. We presented that heterogeneity of precipitate affects its dissolution in terms of repeatability of the results and equilibrating time. A unique 9-year-long experiment on vanadinite stability at a pH range from 2.0-6.0 revealed that among all tested dissolution conditions only the reactions at the pH = 3.5 can perform as the basis for some thermodynamic calculations. It has been concluded that the rate of phase transitions in the Pb-apatites group can be misleading in terms of determining the equilibrium of the system, and the experimental setup designed particularly to provide reliable controls in this aspect should be involved. Means in this respect have been proposed.

10

Study of Ionic Liquids UV-VIS and FTIR Spectra before and after Heating and Spruce Groundwood Dissolution

Danielewicz Dariusz, Kmiotek Magdalena, Surma-Ślusarska Barbara

Fibres & Textiles in Eastern Europe

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2019

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Vol. 27, no. 1 (133)

118--123

EN

The absorption of 1-butyl-3-methylimidazolium chloride and acetate taken from commercial packaging was studied by means of UV-VIS and infrared spectroscopy with some differences observed. Further research showed that heating both 1-butyl-3-methylimidazolium chloride and acetate alone, as well as in the presence of wood pulp, causes the darkening of these ionic liquids. Changes in the colour of ionic liquids associated with a variation in the absorption characteristics of pure ionic liquids and wood solutions in these liquids in UV and visible light are expressed primarily in the widening of the absorption bands. The presence of coloured products formed during their heating, as well as dissolution of the chemical components of wood in ionic liquids, had relatively little effect on the position of individual absorption bands in the spectrum obtained by the FT-IR method. The small differences in the absorption of spruce groundwood solutions in ionic liquids in IR as compared to pure ionic liquids suggest that strong chromophore groups in ionic liquids are created without serious reconstruction of their structure.

PL

W pracy zbadano absorpcję chlorku i octanu 1-butylo-3-metyloimidazoliowego za pomocą spektroskopii UV-VIS i spektroskopii w podczerwieni (FT-IR), zaobserwowano pewne różnice. Dalsze badania wykazały, że zarówno ogrzewanie samego chlorku lub octanu 1-butylo-3-metyloimidazoliowego, jak i ogrzewanie cieczy jonowych, w których rozpuszczono ścier drewna świerkowego, powoduje ciemnienie tych cieczy jonowych. Zmiany barwy cieczy jonowych, związane ze zmianą charakterystyki absorpcji czystych cieczy jonowych i roztworów drewna w tych cieczach w świetle UV i widzialnym wyrażają się przede wszystkim w poszerzaniu pasm absorpcji. Obecność barwionych produktów ogrzewania badanych cieczy jonowych, jak również rozpuszczanie w nich chemicznych składników drewna, wywiera stosunkowo niski wpływ na położenie poszczególnych pasm absorpcji w widmie uzyskanym metodą FT-IR. Niewielkie różnice w widmach FT-IR cieczy jonowych, zawierających rozpuszczony ścier świerkowy w porównaniu z czystymi cieczami jonowymi, mogą wynikać z małego stężenia ścieru w tych cieczach jonowych.

11

Badanie zjawisk rozpuszczania dyfuzyjnego stali reaktywnych w kąpieli cynkowej z dodatkiem bizmutu

Tatarek A., Saternus M.

Ochrona przed Korozją

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2018

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nr 7

186--190

PL

Podczas cynkowania zanurzeniowego bizmut jest często stosowany jako dodatek stopowy do kąpieli. Pierwiastek ten wpływa na stabilizację procesu tworzenia powłoki ochronnej na stali i poprawia jej właściwości powierzchniowe. W pracy przedstawiono wyniki badań zjawisk rozpuszczania stali reaktywnych zawierających krzem w kąpieli cynkowej z dodatkiem 0,5% bizmutu. Zastosowanie warunków modelowych umożliwiło analizę przebiegu procesu rozpuszczania dyfuzyjnego na granicy rozdziału podłoże-kąpiel cynkowa i określenie roli bizmutu. Metodą Boltzmana-Matano wyznaczono wartości współczynnika dyfuzji żelaza w ciekłym cynku w funkcji jego stężenia, w temperaturze 450°C. W przypadku stosowania 0,5% dodatku bizmutu do kąpieli cynkowej można zaobserwować spadek szybkości rozpuszczania dyfuzyjnego podłoża stali reaktywnych. Stwierdzono zmniejszenie szybkości dyfuzji, co jest szczególnie widoczne dla stali sandelinowskiej z krytyczną zawartością 0,05% krzemu, w warstwie dyfuzyjnej powłoki w zakresie występowania fazy ζ.

EN

During hot-dip galvanizing process a bismuth is often applied as alloy addition to zinc bath. This element effects on stabilization of forming process of protective coating on steel and it improves surface properties of coating. The results of investigation of dissolution phenomena of silicon- containing reactive steels in zinc bath with 0,5% bismuth addition have been presented. Due to using the model conditions it is possible to analyse a diffusive dissolution process on the basis metal-zinc bath interface and it determines a bismuth role. The diffusion coefficient of iron dependent on its concentration in liquid zinc has been determined by the Boltzman-Matano method in the temperature of 450°C. Bismuth addition to the zinc bath produces more than twice decrease of dissolution rate of reactive steels. Diffusion rate decreases, that is best visible for Sandelin’s steel with critical silicon addition 0.05%, especially in ζ-phase range in diffusion layer of the coating.

12

Analysis of the Fibroin Solution State in Calcium Chloride/Water/Ethanol for Improved Understanding of the Regeneration Process

Ngo H.-T., Bechtold T.

Fibres & Textiles in Eastern Europe

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2018

|

Vol. 26, no. 6 (132)

43--50

EN

Shaping of fibroin protein from Bombyx mori from calcium chloride/water/ethanol solution is of high interest for the manufacturing of biocompatible structures. Potentiometric titration experiments of the dissolved state permit new insight into the solution state of fibroin as a basis for improved regeneration. Titration experiments and infrared spectroscopy of the solution state support the model of an ion-rich hydration layer and interaction of the solvent with charged and polar groups of the fibroin, rather than through formation of defined calcium complexes. The potentiometric titration curves indicate the formation of calcium complexes at pH values above 9, most probably through involvement of basic amino acids and phenolic groups of tyrosine. After regeneration by the addition of methanol, the regenerated protein was characterised by FTIR, nitrogen and calcium analysis. The analysis of supernatants for their residual protein content indicated minor losses of protein, most probably low molecular weight proteins. The results contribute to an improved understanding of the solution state as a basis for larger scale regeneration, e.g. for the coating of textile fibres with regenerated fibroin.

PL

Fibroiny z Bombyx mori z roztworu chlorku wapnia/wody/etanolu są bardzo interesujące z punktu widzenia wytwarzania biokompatybilnych struktur. Eksperymenty potencjometryczne z miareczkowaniem pozwalają na nowy wgląd w roztwór fibroiny jako podstawy do lepszej regeneracji. Miareczkowanie i spektroskopia w podczerwieni roztworu wspierają model bogatej w jony warstwy hydratacyjnej i oddziaływanie rozpuszczalnika z naładowanymi i polarnymi grupami fibroiny. Potencjometryczne krzywe miareczkowania wskazują na tworzenie się kompleksów wapnia przy wartościach pH powyżej 9, najprawdopodobniej poprzez zaangażowanie podstawowych aminokwasów i grup fenolowych tyrozyny. Po regeneracji przez dodanie metanolu, zregenerowane białko scharakteryzowano za pomocą analizy FTIR, azotu i wapnia. Analiza pod kątem zawartości białka resztkowego wykazała niewielkie straty białka, najprawdopodobniej tego o niskiej masie cząsteczkowej. Wyniki przyczyniły się do lepszego poznania roztworu jako podstawy do regeneracji na większą skalę, np. do powlekania włókien tekstylnych regenerowaną fibroiną.

13

Analysis of the breakthrough phenomena during heavy metal elution from a column packed with municipal waste incineration ash

Zhang W., Yang Y., Suganuma H., Kato S., Suzuki S., Kojima T.

Environment Protection Engineering

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2018

|

Vol. 44, nr 3

63--78

EN

At some point during acid leaching column tests of heavy metals from municipal waste incineration ash, sudden and rapid elution of harmful elements was observed which was called the breakthrough (BT) phenomena. The mechanism was elucidated from the results of measurement of elemental and particle size distribution in the column and batch leaching tests as follows. At the first stage of experimental runs, CaCO3 was dissolved in acidic solution and pH profile along the bed is formed. Some of the minor elements of Zn and Al dissolved by acid at the upper part of the column are precipitated at bottom of the column, leading to the reduction of flow rate of the leachate solution. After leachate pH becomes low by the termination of dissolution of Ca, these deposits are dissolved and thus, the flow rate increases. Most of the trace elements behave as such, which causes the increase of harmful element concentrations in the eluate. Some drastic concentration increase of harmful elements in leachate may occur even after the long period of pseudo stable dissolution behavior in the land-fill site.

14

Dissolution kinetics of smithsonite in boric acid solutions

Abali Y., Bayca S. U., Gumus R.

Physicochemical Problems of Mineral Processing

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2017

|

Vol. 53, iss. 1

161--172

EN

The dissolution of smithsonite in boric acid solutions was investigated. The influence of the reaction temperature, acid concentration, solid-to-liquid ratio, particle size and stirring speed on the zinc extraction were determined in the experiments. The results show that the dissolution rate increases with increasing acid concentration and reaction temperature, and with decreasing particle size and solid-to-liquid ratio. The dissolution results were analyzed by reaction control models. The activation energy of smithsonite in boric acid solution was also calculated.

15

Effect of Acid Dissolution Conditions on Recovery of Valuable Metals from Used Plasma Display Panel Scrap

Kim C.- M., Dharmaiah P., Kim H.-S., Koo J.-M., Yoon J.-S., Hong S.-H., Hong S.-J.

Archives of Metallurgy and Materials

|

2017

|

Vol. 62, iss. 2B

1173--1177

EN

The objective of this particular study was to recover valuable metals from waste plasma display panels using high energy ball milling with subsequent acid dissolution. Dissolution of milled (PDP) powder was studied in HCl, HNO3, and H2SO4 acidic solutions. The effects of dissolution acid, temperature, time, and PDP scrap powder to acid ratio on the leaching process were investigated and the most favorable conditions were found: (1) valuable metals (In, Ag, Mg) were recovered from PDP powder in a mixture of concentrated hydrochloric acid (HCl:H2O = 50:50); (2) the optimal dissolution temperature and time for the valuable metals were found to be 60°C and 30 min, respectively; (3) the ideal PDP scrap powder to acid solution ratio was found to be 1:10. The proposed method was applied to the recovery of magnesium, silver, and indium with satisfactory results.

16

Leaching behaviour of a turkish lateritic ore in the presence of additives

Basturkcu H., Acarkan N.

Physicochemical Problems of Mineral Processing

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2016

|

Vol. 52, iss. 1

112--123

EN

This paper investigates the dissolution mechanism of a lateritic nickel ore from the Caldag Region of Manisa in Turkey. The ore sample contained 1.2% Ni, 24.8% Fe, and 0.062% Co. The optimum leaching conditions were found to be temperature 80 oC, particle size -74 μm, H2SO4 concentration 200 g/dm3, solids ratio (by weight) 10% and leaching duration 8 h. The extractions of 98.2% Ni, 98.6% Fe and Co 98.9% were obtained under these conditions. Additionally, the effects of additional substances such as NaCl, Na2S2O5, Na2SO4, and KCl were investigated in order to decrease the leaching duration. The results showed that the additives accelerated the leaching kinetics and achieved nearly the same nickel and cobalt extractions at the end of 4 h compared to the results obtained after 8 h without the additives. If the additives containing chlorine were used, it was determined that the iron extraction showed no increase, although both the nickel and cobalt extractions increased.

17

AFM studies of pits formation on KBr(1 0 0) during its dissolution by water

Pers J., Barwiński B., Grodzicki M., Ciszewski A.

Materials Science Poland

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2016

|

Vol. 34, No. 4

863--867

EN

The formation of etch pits along screw dislocations on KBr(1 0 0) surface during its dissolution by water is investigated by means of atomic force microscopy (AFM). Clean KBr(1 0 0) is obtained by cleavage. A weak solution of water in isopropyl alcohol is used to investigate the etching in real time. Observations of the etch pit evolution with etching time show that concentration of atomic steps on the pit walls and dissolution rate of the walls vary up to complete dissolution of the screw dislocation. The screw dislocation removal stabilizes the dissolution, resulting in constant values of atomic steps concentration on the pit walls and their dissolution rate during further etching, which continues according to the crystal dissolution stepwave model. It was found that the movement of AFM scanning tip essentially affected the etching process.

18

Efekt przepływu elektrolitu na topografię powierzchni w obróbce elektrochemicznej (ECM)

Kozak J.

Inżynieria Powierzchni

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2016

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Nr 4

18--22

PL

Obróbka elektrochemiczna (ECM) należy do efektywnych sposobów kształtowania elementów o skomplikowanej geometrii z materiałów trudno skrawalnych. W artykule przedstawiono badania wpływu hydrodynamiki elektrolitu na topografię powierzchni obrobionej. Omówiono problem powstawania defektów hydrodynamicznych na powierzchni anody wywołanych niestabilnością hydrodynamiczną i tworzeniem się struktur koherentnych w warstwie przyściennej, co może prowadzić do swoistego rezonansu hydro-elektrochemicznego.

EN

Electro-Chemical Machining (ECM) is one of the effective ways of shaping parts with complex geometries from difficult-to-machine materials. This article presents a study on the influence of the hydrodynamics of electrolyte on the topography of the surface finish. It discusses the problem of the formation of hydrodynamic defects on the surface of the anode induced by hydrodynamic instability and the formation of coherent structures in the boundary layer, which may lead to a specific hydro-electrochemical resonance.

19

The utilisation of fly ash in CO2 mineral carbonation

Jaschik J., Jaschik M., Warmuziński K.

Chemical and Process Engineering

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2016

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Vol. 37, nr 1

29--39

EN

The fixation of CO2 in the form of inorganic carbonates, also known as mineral carbonation, is an interesting option for the removal of carbon dioxide from various gas streams. The captured CO2 is reacted with metal-oxide bearing materials, usually naturally occurring minerals. The alkaline industrial waste, such as fly ash can also be considered as a source of calcium or magnesium. In the present study the solubility of fly ash from conventional pulverised hard coal fired boilers, with and without desulphurisation products, and fly ash from lignite fluidised bed combustion, generated by Polish power stations was analysed. The principal objective was to assess the potential of fly ash used as a reactant in the process of mineral carbonation. Experimental were done in a 1 dm 3 reactor equipped with a heating jacket and a stirrer. The rate of dissolution in water and in acid solutions was measured at various temperatures (20 – 80ºC), waste-to-solvent ratios (1:100 – 1:4) and stirrer speeds (300 – 1100 min -1). Results clearly show that fluidised lignite fly ash has the highest potential for carbonation due to its high content of free CaO and fast kinetics of dissolution, and can be employed in mineral carbonation of CO2.

20

Dissolution of Metal Supported Spent Auto Catalysts in Acids

Fornalczyk A., Kraszewski M., Willner J., Kaduková J., Mrážiková A., Marcinčáková R., Velgosová O.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

233--236

EN

Metal supported auto catalysts, have been used in sports and racing cars initially, but nowadays their application systematically increases. In Metal Substrate (supported) Converters (MSC), catalytic functions are performed by the Platinum Group Metals (PGM): Pt, Pd, Rh, similarly to the catalysts on ceramic carriers. The contents of these metals make that spent catalytic converters are valuable source of precious metals. All over the world there are many methods for the metals recovery from the ceramic carriers, however, the issue of platinum recovery from metal supported catalysts has not been studied sufficiently yet. The paper presents preliminary results of dissolution of spent automotive catalyst on a metal carrier by means of acids: H2SO4, HCl, HNO3, H3PO4. The main assumption of the research was the dissolution of base metals (Fe, Cr, Al) from metallic carrier of catalyst, avoiding dissolution of PGMs. Dissolution was the most effective when concentrated hydrochloric acid, and 2M sulfuric acid (VI) was used. It was observed that the dust, remaining after leaching, contained platinum in the level of 0.8% and 0.7%, respectively.