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Wyszukujesz frazę "rock phosphate" wg kryterium: Temat


Wyświetlanie 1-10 z 10
Tytuł:
The role of rock phosphates in sustainable agriculture: the Hungarian experience with Algerian rock phosphate
Autorzy:
Nemeth, T.
Csatho, P.
Osztoics, E.
Powiązania:
https://bibliotekanauki.pl/articles/801085.pdf
Data publikacji:
1998
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
rock phosphate
sustainable agriculture
Hungary
agriculture
fertilization
nutrient balance
phosphate
soil
plant nutrient
superphosphate
Opis:
From the early 60's till the late 80's, in many countries - among them also in Hungary - agricultural production went through a tremendous development. In Hungary there was a 2-3-fold increase in the average yields of winter wheat, and maize - the two main crops - in comparison to those of the 50's. One of the main factors determining these developments was the increasing use of mineral fertilizers. From the turn of the century till the late 50's, nutrient balances in Hungary were strongly negative: 20 - 30 kg/ha/year less N and K₂O, and 10 kg/ha/year less P₂O₅ was given to the fields in the different forms (farmyard manure, mineral fertilizer and by-products, etc.), than was removed by the harvested yields. Nutrient balances of P became positive in the early 60's, while balances of N and K in the early 70's, resp. Then, for 20 years, N balances were positive by 10 - 20 kg/ha/year, while both P₂O₅ and K₂O balances by 30 - 50 kg/ha/year, resp. These long-term positive nutrient balances resulted in the NPK enrichment of our soils, which was also proven by the national soil test series. During the 80's, for example, the amount of yearly applied mineral fertilizer was 230 - 280 kg/ha N + P₂O₅ + K₂O/arable land. In certain regions N leaching could cause environmental damage, while, as a result of the P-Zn antagonism, on the fields poorly supplied with Zn, overfertilization with P resulted in 1 - 2 t/ha/year maize yield losses. From the early 90's, however, when political and ecological changes took place in the country, the free market was introduced, and state subsidies on mineral fertilizer were withdrawn, there was a sharp decrease in mineral fertilizer use: applied N dropped to 1/5th, P and K to 1/20th of the amount used in the 80's. This dramatic decrease resulted in the change of nutrient balances: in 1991 the balance for N was -60, for P₂O₅ -30, and for K₂O -40 kg/ha for the whole country, resp. In 1992 and 1993 the situation was similar, while in 1994 a slight increase in mineral fertilizer use was observed. According to our estimation, mineral fertilization of 150 kg/ha/year N + P₂O₅ + K₂O is sufficient for long-term sustainable plant nutrition in Hungary, if farmyard manure application and the incorporation of byproducts remains on the recent level. During intensive fertilization practice, emphasis was on the quantity, while crop and soil demands for specific or more economic fertilizers were not taken into consideration. For N, lime ammonium nitrate, for P superphosphate, and for K, potash chloride was used on almost the whole area. As a new attempt to find more economic P sources, Algerian rock phosphate was checked in field trials, set up on characteristic acidic soils in different regions of Hungary, as well as other Central European countries. The first two-year results are discussed in the presentation.
Źródło:
Zeszyty Problemowe Postępów Nauk Rolniczych; 1998, 456
0084-5477
Pojawia się w:
Zeszyty Problemowe Postępów Nauk Rolniczych
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selective depression of Escherichia coli on flotation of collophanite and dolomite
Autorzy:
Li, JiaXin
Nie, GuangHua
Jiang, Ying
Luo, GuoJv
Li, Jie
Powiązania:
https://bibliotekanauki.pl/articles/2146918.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Escherichia coli
collophanite
dolomite
flotation
phosphate rock
Opis:
The phosphate rock flotatio n test was carried out using Escherichia coli E. coli ) as a depressant of dolomite. The results showed that E. coli had a great selective depression on dolomite during flotation. With E. coli as a depressant of dolomite, a useful beneficiation index of phosphorus concentrate with P2O5 grade of more than 30% and MgO content less than 1.2% can be obtained by closed circuit of one stage roughing and one stage cleaning. Furthermore, the depression mechanism of E. coli was studied by ad sorption experiments, infrared spectrum, and zeta potential. This study shows that the adsorption ability of E. coli onto dolomite is stronger than that of collophanite. When the pH is greater than 6, E. coli are chemically adsorbed on the surface of the c ollophanite and dolomite,which also increases the negative charge on the surface of the two minerals. The selective adsorption of E. coli cells to dolomite was best when the pH value is about 7.8.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 4; art. no. 150604
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of phosphate quality on foam generation during the phosphoric acid production process
Autorzy:
Anouar, Islaam
Jouraiphy, Rim
Essallaki, Hicham
Mazouz, Hamid
Yousfi, Samia
Boulif, Rachid
Essaid, Bilal
Bouamrani, Mouna L.
Powiązania:
https://bibliotekanauki.pl/articles/1447543.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
phosphate rock
foam
organic carbon
carbonate
foamingability test
Opis:
The presence of organics materials in phosphate ores generates foam during the manufacture of phosphoric acid, thus affecting the production performance and the quality of the products. Today, in the phosphate industry defoamers are used to reduce the negative impact of foam phosphoric production. In the present work, we focused on root cause evaluation for foam generation during the phosphoric acid production process, we evaluated the effect of phosphate rock quality in terms of organic carbon (OC) and carbonate content, on foam generation using a laboratory protocol for foaming ability evaluation. The results show that there is a relationship between the volume of the foam generated and the values of those impurities, while the volume of foam generated is higher when the concentration of OC and Carbonate is high. In our work, we confirm that the foaming ability of the phosphate rock can be avoided if the concentration of organic carbon less than 0.1% and less than 3% for carbonate.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 2; 48-57
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of measuring process properties on phosphate rock slurry rheology based on Brookfield method
Autorzy:
Chen, Aoao
Zhang, Qin
Powiązania:
https://bibliotekanauki.pl/articles/2175436.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
phosphate rock
grinding
concentration
rheological properties
apparent viscosity
Opis:
This research aims to explore how the flotation process conditions influence the rheological properties of phosphate rock slurry. The apparent viscosity of phosphate rock slurry was measured by Brookfield DVNext rheometer. Different mineral types, grinding time, slurry mass concentration and reagent systems were adopted to study the viscosity behavior of phosphate rock slurry. The results showed that under the same conditions, the apparent viscosity of apatite and dolomite slurry was basically the same, and the apparent viscosity of the slurry after mixing the two minerals was basically the same as that of single mineral. For the same slurry concentration, the mineral particle size had a significant effect on the rheological behavior of the slurry, and its apparent viscosity increased exponentially with the decrease of particle size. In addition, phosphate rock slurry showed shear thickening fluids characteristics when the slurry concentration is 20%-40%, but changed to pseudoplastic fluid at high concentration (60%). Sulfuric acid as pH regulator and inhibitor had little effect on the rheology of slurry; when GJBW and NaOL were added as collectors, the rheology of slurry changed, and the effect of GJBW was more obvious.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 156202
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of granulating factor at variable humidity on granulation of partially acidulated phosphate rocks
Wpływ czynnika granulującego przy zmiennej wilgotności na granulację fosforytów częściowo rozłożonych
Autorzy:
Hoffmann, K.
Rolewicz, M.
Skut, J.
Hoffmann, J.
Powiązania:
https://bibliotekanauki.pl/articles/388222.pdf
Data publikacji:
2013
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
fertilizers
granulation
partially acidulated phosphate rock
nawozy
granulacja
fosforyty
Opis:
Unstable situation on fertilizer raw material market emerges the need to find substitute for superphosphate fertilizers. PAPR-type phosphate fertilizers (partially acidulated phosphate rock) constitute the most relevant alternative. PAPR-type fertilizers are formed by reaction of phosphate rock with nonstoichiometric, in relation to reaction during superphosphate production process, portion of mineral acid. The resulting product contains an available (soluble in water and/or in neutral ammonium citrate) and less available (soluble in mineral acids) forms of phosphorus. Possibility of using low-grade phosphate rock represents a great advantage of PAPR-type over superphosphatic manufacturing process, where applying phosphate rock of high P2O5 at low impurities content is highly recommended. Granulation process is an essential stage of PAPR-type fertilizers production. Granulation significantly reduces the dust emissions during the fertilizers application furthermore limits the regression of fertilizers in soil to unavailable forms (so-called the aging processes of fertilizers). Optimization of process parameters is very important for economic and ecological reasons because this process is one of the most energy consuming in whole cycle of PAPR-type fertilizers production. PAPR-type fertilizer preparations obtained under laboratory conditions were subjected to examinations. Products were characterized by a variable humidity, which was achieved by altering the concentration of mineral acid used for investigations. The second variable factor was the type of liquid used for granulation. Both, the sieve analysis and determination of resistance were carried out for classification of obtained granules.
Niestabilna sytuacja na rynku surowców nawozowych stwarza konieczność znalezienia substytutu dla nawozów superfosfatowych. Najważniejszą alternatywą wydają się być nawozy fosforowe typu PAPR (partially acidulated phosphate rock). Nawozy typu PAPR powstają w wyniku reakcji fosforytów z niestechiometryczn ą, względem reakcji produkcji superfosfatów, ilością kwasu. Tak powstały produkt zawiera formy fosforu zarówno łatwo przyswajalne (rozpuszczalne w wodzie i/lub w obojętnym cytrynianie amonu), jak i nieprzyswajalne (rozpuszczalne tylko w kwasach mineralnych) przez rośliny. Zaletą tego rodzaju nawozów jest fakt, że do ich produkcji można wykorzystać fosforyty o znacznie mniejszej zawartości P2O5 niż jest to wymagane dla procesu produkcji nawozów superfosfatowych. Proces granulacji jest niezbędnym elementem procesu otrzymywania nawozów typu PAPR ponieważ znacznie zmniejsza emisję pyłów w czasie stosowania nawozów, dodatkowo granulacja nawozów fosforowych znacznie ogranicza uwstecznianie się nawozów do form nieprzyswajalnych (tzw. procesy starzenia się nawozów) w glebie. Optymalizacja parametrów procesu granulacji jest bardzo istotna ze względów ekonomicznych oraz ekologicznych, ponieważ proces ten jest jednym z najbardziej energochłonnych w całym cyklu produkcji nawozów. Do badań wykorzystano preparaty nawozów fosforowych typu PAPR otrzymane w laboratorium. Otrzymane preparaty charakteryzowały się zmienną wilgotnością, co osiągnięto poprzez zmianę stężenia kwasu użytego do reakcji. Drugim zmiennym czynnikiem był rodzaj cieczy użytej do procesu granulacji nawozów typu PAPR. W celu klasyfikacji otrzymanych granulatów przeprowadzono analizę sitową oraz oznaczono wytrzymałość otrzymanych preparatów.
Źródło:
Ecological Chemistry and Engineering. A; 2013, 20, 9; 1049-1056
1898-6188
2084-4530
Pojawia się w:
Ecological Chemistry and Engineering. A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhanced biosolubilization of mid-low grade phosphate rock by formation of microbial consortium biofilm from activated sludge
Autorzy:
Xiao, Chunqiao
Wu, Xiaoyan
Zhu, Lei
Yu, Tong
Xu, Zhenghe
Chi, Ruan
Powiązania:
https://bibliotekanauki.pl/articles/110353.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
biosolubilization
phosphate rock (PR)
microbial consortium
activated sludge
biofilm
Opis:
Mid-low grade phosphate rock (PR) is a potential source of free phosphate to facilitate crop growth, but a cost effective and environmentally responsible extraction process is required. In this study, the capacity of a microbial consortium from activated sludge to solubilize PR in a laboratory-scale column reactor was investigated. The microbial consortium proved capable of efficiently releasing soluble phosphate in the reactor effluent over the 90-day trial. The microbial consortium grew well in the column system as evidenced by reduced chemical oxygen demand (COD) in the reaction solution. Biofilm formation was identified as critical for biosolubilization of the mid-low grade PR. Imaging of the biofilm by scanning electron microscopy (SEM) revealed a dense network of microbial cells embedded in extracellular polymeric substances (EPS). The biofilm contained both oxic and anoxic zones. The pH decreased significantly in both the biofilm and the reaction solution during operation, indicating healthy growth of the microbial consortium with corresponding acid generation and subsequent enhancement of phosphate solubilization.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 1; 217-224
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A first-principle study of the effect of Fe/Al impurity defects on the surface wettability of dolomite
Autorzy:
Chen, Hong
Ao, Xianquan
Cao, Yang
Li, Cuiqin
Jiang, Chunyan
Powiązania:
https://bibliotekanauki.pl/articles/2146916.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
density functional theory
phosphate rock flotation
dolomite
surface wettability
density of states
Opis:
The presence of Fe and Al atoms in large quantities in phosphate ores can significantly affect the surface properties of the minerals during flotation. In this study, the effects of Fe/Al impurities on the adsorption of H2O molecules on dolomite, including the density of states (DOS), Mulliken bond group values, and charge groups, were investigated and the adsorption energy was analyzed using density functional theory. The results show that the adsorption of H2O molecules on perfect and Fe/Al-substituted dolomites is weak chemisorption, and the Fe and Al impurities weaken and enhance the adsorption capacity of H2O molecules, respectively. Therefore, the hydrophilicity of the dolomite surface increases in the following order: Fe-substituted dolomite < perfect dolomite < Al-substituted dolomite. The Mulliken charge and bond group analysis shows that the adsorption of H2O molecules on dolomite is primarily through the interaction between Ow and Ca atoms, where the d orbitals of Ca atoms provide charges for Ow atoms to form ionic bonds, which related to the poor electronegativity of Ca atoms and their weak valence electron binding ability. The DOS analysis shows that, during the adsorption of H2O molecules on dolomite, Mg and Al atoms have less influence on the dolomite surface, whereas Fe and Ca atoms undergo competitive adsorption, which inhibits the interaction between Ca atoms and H2O molecules on the dolomite surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 4; art. no. 150702
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on bioavailability of lead from products of phosphate rock acidulation obtained by PAPR technique
Badanie przyswajalności ołowiu w produktach rozkładu surowców fosforowych techniką PAPR
Autorzy:
Hoffmann, K.
Kasprzyszak, A.
Skut, J.
Hoffmann, J.
Powiązania:
https://bibliotekanauki.pl/articles/388831.pdf
Data publikacji:
2013
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
partially acidulated phosphate rock
heavy metals
lead
voltammetry
fosforyty częściowo rozłożone
metale ciężkie
ołów
woltamperometria
Opis:
Use of phosphate fertilizers in the world constantly decreases in the last few years. The reason is increase of a unit prices of nutritious components what results in automatic growth of phosphate fertilizers prices. It is a well-known fact that phosphorus in a fertilizer causes not only growth but also a stabilization of plant production. That’s why economic aspects exacted a necessity of searching cheaper resolutions for plant fertilization. Fertilizers containing partially acidulated phosphate rock like PAPR show long-lasting activity thanks to content of phosphorus with different solubility extent. Therefore, they can be an alternative for present sources of phosphorus like superphosphate. Very important is an optimization of PAPR composition. Content of macro- and micrślements like zinc, manganese, copper, iron determine usefulness of definite preparation for fertilization goals. Knowledge of heavy metals concentration in given fertilizer may turn out fundamental if we are talking about ecological and healthy aspects of using partially acidulated phosphate rocks. Products type PAPR were made in laboratory by dissolving phosphate rocks with non-stoichiometric quantity of sulphuric acid. Next mineralization of appropriate fertilizer weighted amount was conducted in the aim of determine heavy metal concentration. Lead content in fertilizers type PAPR was studied in Autolab device using differential pulse voltammetry method.
Nawozy zawierające częściowo rozłożony fosforyt, czyli nawozy typu PAPR (z ang. partially acidulated phosphate rock) wykazują długotrwałe działanie dzięki zawartości fosforu o różnym stopniu rozpuszczalności. Ważna jest optymalizacja składu nawozów typu PAPR. Znajomość poziomu stężeń metali ciężkich w danym nawozie może się okazać kluczowa, jeśli chodzi o ekologiczne i zdrowotne aspekty wykorzystywania nawozów fosforowych częściowo rozłożonych. W badaniach zastosowano produkty typu PAPR otrzymane w warunkach laboratoryjnych poprzez roztwarzanie fosforytów z niestechiometryczną ilością kwasu siarkowego. Następnie przeprowadzano mineralizację uzyskanych nawozów w celu oznaczenia stężenia ołowiu. Zawartość ołowiu w nawozach typu PAPR badano za pomocą urządzenia Autolab metodą woltamperometrii pulsowej różnicowej.
Źródło:
Ecological Chemistry and Engineering. A; 2013, 20, 4-5; 555-563
1898-6188
2084-4530
Pojawia się w:
Ecological Chemistry and Engineering. A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Release of trace metals to the soil solution from a phosphate rock containing soil at different acid loads
Autorzy:
Csillag, J.
Lukács, A.
Osztoics, E.
Csathó, P.
Baczó, G.
Powiązania:
https://bibliotekanauki.pl/articles/9757109.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Tematy:
trace metal
soil solution
phosphate rock
phosphorus source
acid load
toxic element
environmental hazard
metal concentration
Źródło:
Annales Universitatis Mariae Curie-Skłodowska. Sectio E. Agricultura; 2004, 59, 4; 1829-1836
0365-1118
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska. Sectio E. Agricultura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rail transport igneous phosphate rock
Transport kolejowy apatytów
Autorzy:
Westhuizen, A.
Beer, G.
Powiązania:
https://bibliotekanauki.pl/articles/340252.pdf
Data publikacji:
2004
Wydawca:
Główny Instytut Górnictwa
Tematy:
transport apatytów
transport materiałów promieniotwórczych
prawo ochrony radiologicznej
transport of apatites
transport of igneous phosphate rock
radiological defense low
Źródło:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa; 2004, 1; 25-26
1643-7608
Pojawia się w:
Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
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