Browsing by Subject "pyromorphite"

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Mineralogiczno-geochemiczna analiza wpływu strzelnicy sportowej na środowisko
(Data obrony: 2016-07-19) Kozień, Dawid
Wydział Geologii, Geofizyki i Ochrony Środowiska
Celem pracy jest ocena wykorzystania zabiegów inżynierii mineralnej poprzez aplikację nawozów fosforanowych do zminimalizowania mobilności ołowiu w glebach z obszaru strzelnic sportowych. Przedstawiono wyniki badań gleb i pocisków ołowiowych pobranych z strzelnicy sportowej Pasternik na terenie Krakowa. Próbki glebowe, jak i wydzielone frakcje ilaste, zostały poddane analizie XRD, XRF, AAS oraz spektroskopii Ramana. Wykonano eksperymenty przemywani gleb i zwilżania pocisków roztworem imitującym kwaśne deszcze o pH=4,2 z nawozem fosforanowym. Największe zawartości ołowiu w glebie obserwowano w rejonie nasypu strzelniczego. Aplikacja nawozów fosforanowych np. azofoski unieruchamia ołów w formy trudno rozpuszczalne w glebie, co powoduje spadek ilości mobilnego ołowiu występującego w przesączu glebowym. Mechanizm unieruchamiania ołowiu polega na zamianie węglanów ołowiu (cerusyt, hydrocerusyt) na trudniej rozpuszczalne siarczany ołowiu (anglezyt) i bardzo ciężko rozpuszczalne fosforany ołowiu (piromorfit).
Access status: Open Access ,
Removal of REE and Th from solution by co-precipitation with Pb-phosphates
(2023) Sordyl, Julia; Staszel, Kacper; Leś, Mikołaj; Manecki, Maciej
Wydział Geologii, Geofizyki i Ochrony Środowiska
The supply of technologically important rare earth elements (REE) is a concern in Europe, hence the recovery of REE from alternative sources has recently become widely investigated. One of the problems is the lack of cost-effective technologies for REE recovery from leaching solutions. The present work investigated the potential for recovering REE and Th from leaching solutions by co-precipitation with Pb phosphates. A set of four experiments were conducted using analytical reagent grade chemicals to analyze the effects of Pb and different pH on the efficiency of REE and Th removal from aqueous solutions. After selecting the best conditions, two additional experiments were performed using solutions obtained from leaching REE-rich apatite mine waste. The precipitates resulting from the experiments as well as the solutions before and after precipitation were analyzed. It was found that the formation of a crystalline mixture of REE- and Th- enriched pyromorphite, $Pb_{5}(PO_{4})_{3}Cl$, and Pb-phosphates, about which little has been known so far, was responsible for complete (>99%) removal of REE and Th from aqueous solutions at pH 4 and 6. At lower pH, the removal is incomplete except for Sc and Th, which probably form a distinct phases. Besides that, no fractionation of LREE and HREE was observed. The experiments included the study of solutions resulting from the leaching of REE-rich apatite waste, which may contribute to the development of new technologies for REE recovery from wastes.
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Transformation of cerussite into lead apatites upon reaction with phosphate ions
(Data obrony: 2017-09-26) Oknińska, Joanna
Wydział Geologii, Geofizyki i Ochrony Środowiska
During natural reactions and in-situ immobilization of lead thermodynamically stable phases like pyromorphite ($Pb_{5}(PO_{4})_{3}Cl$) can form by replacing cerussite. In experiments in which lead carbonate have been reacted with phosphate solutions, cerussite is partially or completely replaced by polycrystalline pyromorphite and hydroxypyromorphite. The study was aimed to investigate the influence of pH and presence or absence of chloride ion on the transformation reaction. Cerussite crystals were put into 2M ($NH_{4})_{2}HPO_{4}$ solution or into 0,7M $NH_{4}Cl$ and 2M ($NH_{4})_{2}HPO_{4}$ solution, the pH was set to initial values of 3, 5 and 7. The products were identified with X-Ray powder diffraction. The microtextural relationships between parent and product phases, determined by scanning electron microscopy and electron microprobe analysis, are consistent with coupled dissolution-precipitation mechanism. In presence of chloride ions, regardless of the initial pH conditions, the dissolution of cerussite is followed by crystallization of pyromorphite in form of nonporous cover that stops diffusion of ions and progress of the reaction. When chloride ions are not available hydroxypyromorphite and, at low pH conditions, other phases such as $Pb_{3}(PO_{4})_{2}$ and $PbHPO_{4}$ are formed.
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Wpływ kwasów organicznych na efektywność unieruchamiania ołowiu w postaci piromorfitu
(Data obrony: 2014-09-29) Buczek, Renata
Wydział Geologii, Geofizyki i Ochrony Środowiska
Pyromorphite is formed in the soil by the application of the lead in situ immobilization using phosphate compounds is exposed in the rhizosphere of naturally occurring organic acids. Experiments were conducted to assess the effect of acids (citric, acetic, oxalic) previously complexed with $Pb$ (experiment 1) and without prior complexation (experiment 2), on the course and products of synthesis pyromorphite. Concentrations of $Pb^{2+}$, $PO{3\atop4}^{-}$, $Cl^{-}$ in samples and the pH of the solutions allowed to determine the effectiveness of $Pb$ immobilization and changes in the reaction system. It has been found that the factor determining the efficiency of immobilization $Pb$ in the presence of organic acids is pH (the protonation reaction of $Pb$), and the formation of $Pb$-acids complexes is secondary factor. XRD and SEM were used to identify the phase composition and morphology characteristics of the sediments. Acids affect morphology and growth of pyromorphite (dissolution and recrystallization reactions). Organic acids used in this study constitute a destabilizing factor crystallization of pyromorphite. Macroscopic observations of changes in concentrations in the solutions are not sufficient to identify the elementary reaction mechanisms.
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Wpływ kwasu glukonowego na rozpuszczalność piromorfitu
(Data obrony: 2013-09-13) Borowicz, Paweł
Wydział Geologii, Geofizyki i Ochrony Środowiska
Phosphate-induced lead immobilization method is based on the fact that newly formed mineral, pyromorphite, is a highly insoluble phase. However, there is a number of factors capable of decreasing stability of pyromorphite. Among them are low-molecular-weight organic acids (LMWOA) secreted to the soil by numerous species of microorganisms and plants. Presented studies investigate the relation between pyromorphite and gluconic acid (GA), one of the most common LMWOA in the soil. The conducted experiments includes dissolution of pyromorphite in the presence of GA, having regard to the pH of the solution or concentration of GA, and formation of pyromorphite in the presence of GA (homogeneous and heterogeneous transformations). The studies indicate that GA increase the dissolution of pyromorphite through decreasing pH of the solution, Pb-organic complexation and increasing the ionic strength of the solution. GA inhibits growth of pyromorphite crystals through formation of complexes with crystal seeds and reducing activity coefficient of lead cations.
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Wpływ właściwości substratów na krystalizację piromorfitu na powierzchni (tlenowodoro)tlenków żelaza
(Data obrony: 2017-09-26) Radlińska, Marcelina
Wydział Geologii, Geofizyki i Ochrony Środowiska
Crystallization of pyromorphite, the most stable lead mineral, is widely used for immobilization of lead present in soil. Pyromorphite formation on goethite, the most common iron (oxyhydro)oxide in soil, had been described in many scientific papers. However the knowledge knowledge of pyromorphite crystallization on other secondary iron minerals is still unsufficient. In this study the experiments of pyromorphite formation on 6 synthetic iron (oxyhydr)oxides and two natural materials (bog iron ore and a sludge from water treatment plant). were conducted in two systems: (1) the addition of lead ions to P-adsorbed materials and (2) the addition of PO43- ions to Pb-adsorbed materials. It has been shown that the amount and morphology of pyromorphite strongly depends on the material used as substrate. The order of the reagent addition influences the process as well. The results suggest that sorption/desorption capacities of iron minerals strongly influence a new phase formation. Still there is the need for further research to know the details of factors and mechanisms that influence described process.