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    Wyświetlanie 1-5 z 5
    Tytuł:
    Seepage process on weathered crust elution-deposited rare earth ores with ammonium carboxylate solution
    Autorzy:
    Zou, Hualiang
    Zhang, Zhenyue
    Chen, Zhuo
    Liu, Defeng
    Chai, Xiuwei
    Zhang, Han
    Chi, Ru-an
    Powiązania:
    https://bibliotekanauki.pl/articles/1449672.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    permeability
    weathered crust elution-deposited rare earth ore
    ammonium carboxylate
    hydrodynamics
    Opis:
    In order to reveal the seepage law of ammonium carboxylate solution in the in-situ leaching process of weathered crust elution-deposited rare earth ores, the effects of concentration, pH, temperature, particle size and porosity on permeability were discussed in this paper. The results shown that the seepage of the leaching agent solutions in the rare earth ore follows Darcy's law and displays a laminar flow under the conditions of this experiment and seepage velocity can be increased by changing leaching conditions. The permeability coefficients are inversely proportional to concentrations of ammonium acetate, ammonium tartrate and ammonium citrate whose concentration is greater than 0.7wt%, because the insoluble complexes formed by the reaction of ammonium citrate with RE3+ at lower concentration n decrease the permeability coefficient. The permeability coefficients of ammonium carboxylate solutions increase firstly and then decrease with the pH increased. The maximum of permeability coefficients of ammonium acetate, ammonium tartrate and ammonium citrate solution were 2.92, 1.91 and 2.70, respectively, while the pH of solution were 5, 6 and 7, respectively. Increasing temperature is beneficial for the seepage of ammonium carboxylate solution in orebody, therefore, it is helpful for leaching operation in summer. Moreover, clay minerals particle size and porosity are the key factors affecting the permeability of ammonium carboxylate solution in orebody. The permeability coefficients of ammonium acetate, ammonium tartrate and ammonium citrate solutions are 2.92×104cm/s,1.90×10-4cm/s and 2.69×10-4cm/s, respectively, at the same temperature of 293K, original particle size and porosity of the ore. Ammonium acetate solution has the best permeability in orebody.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2020, 56, 1; 89-101
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Direct reuse of rare earth oxalate precipitation mother liquor for rare earth leaching
    Autorzy:
    Wu, Xiaoyan
    Zhou, Fang
    Feng, Jian
    Liu, Xueme
    Zhang, Zhenyue
    Chi, Ruan
    Powiązania:
    https://bibliotekanauki.pl/articles/109869.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    weathered crust elution-deposited rare earth ore
    oxalic acid
    precipitation
    mother liquor
    Opis:
    In the recovery process of rare earth (RE) from the weathered crust elution-deposited rare earth ore, ammonium sulfate is used as the leaching liquor to leach RE, and then the leachate containing RE3+ can be precipitated by oxalic acid and the RE oxalate precipitation mother liquor is reused for RE leaching process after removing the residual oxalic acid by precipitation with calcium hydroxide. However, the reuse process of precipitation mother liquor cannot proceed in the strong acid and alkali restricted areas and the discharge of mother liquor which contains a large amount of ammonium salt will cause ammonia-nitrogen waste and pollution. In order to realize the reuse of the precipitation mother liquor in this area, the direct reuse of RE oxalate precipitation mother liquor for RE leaching was investigated in this study. The RE oxalate precipitation process and the RE leaching process with oxalic acid were studied. The results showed that the residual oxalic acid concentration in the mother liquor can be controlled lower than 0.8 g/dm3 at pH 2-3 when the RE concentration in the leachate was 0.1- 1.5 g/dm3 and the RE precipitation rate reached to 94%. In addition, RE leaching efficiency was up to 90% while the oxalic acid concentration in the prepared mother liquor was 0.2-0.8 g/dm3, pH 2-3. Therefore, the precipitation mother liquor with oxalic acid concentration less than 0.8 g/dm3 could be directly reused for RE leaching. However, considering the different performance of RE ores, the recommended oxalic acid concentration in the direct used precipitation mother liquor was lower than 0.6 g/dm3.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 3; 760-769
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Seepage mechanism during in-situ leaching process of weathered crust elution-deposited rare earth ores with magnesium salt
    Autorzy:
    Liu, Defeng
    Zhang, Zhenyue
    Chi, Ruan
    Powiązania:
    https://bibliotekanauki.pl/articles/110849.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    seepage mechanism
    weathered crust elution-deposited rare earth ores
    in-situ leaching
    magnesium salt
    Opis:
    To reveal seepage mechanism during in-situ leaching process of weathered crust elution deposited rare earth ores with magnesium salt, the effects of particle gradation, particle migration, Atterberg limit on the permeability coefficient were investigated, and the relation between the particle size and rare earth content was discussed. The results showed that the ore in the humic layer (HL) with high porosity and permeability was uniformly graded particles. The ore in the completely weathered layer (CWL) with low porosity and permeability belonged to dense-graded particles. The ore in the partly weathered layer (PWL) was open-graded particles, whose permeability fell in between the HL and the PWL. The change of -0.075mm particles content was the largest in the leaching process. When - 0.075mm particle content was less than 30%, the migration ability of fine particles and the permeability coefficient decreased gradually. On the contrary, the migration ability of fine particles gradually remained stable, and the change in the permeability coefficient was not obvious. The liquid limit (LL) in the Atterberg limit of HL, CWL and PWL was inversely proportional to the permeability coefficient, and followed the order: LLHL < LLPWL < LLCWL. With the -0.075mm particle content increasing, the LL of the ore samples increased gradually and finally tended to be stable. The peak value of rare earth concentration appeared earlier and the rare earth content decreased gradually with the increase of the ore particle size. This work provided a theoretical basis for achieving high-efficient mining of weathered crust elution-deposited rare earth ores.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2020, 56, 2; 350-362
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of chromatographic plate theory on the weathered crust elution-deposited rare earth ore with carboxylate
    Autorzy:
    Zhang, Zhenyue
    Wang, Guangshuai
    Li, Chunhua
    Chi, Ruan
    Long, Fei
    Chen, Zhuo
    Chi, Xiao Wang
    Liu, Defeng
    Powiązania:
    https://bibliotekanauki.pl/articles/1446022.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    weathered crust elution-deposited rare earth ore
    carboxylate ammonium
    mass transfer
    theory plate
    rare earth
    Opis:
    To improve the leaching process of rare earth and reduce the impurities in the leachate, the carboxylate ammonium, such as ammonium acetate, ammonium citrate and ammonium tartrate, were selected as lixiviant to compare the effects of concentration, flow rate, pH and temperature on leaching mass process of rare earth and aluminum. Meanwhile, the leaching behaviors of rare earth and aluminum leached by three kinds of carboxylate ammonium were analyzed by chromatographic plate theory. The relationship between the flow rate and height equivalent (HETP) could fit well with the Van Deemter equation and there was an optimal flow rate (uopt) for the leaching of the rare earth and aluminum. Besides, the conditions of carboxylate ammonium lixiviant were optimized. The optimum concentrations of ammonium acetate, ammonium tartrate and ammonium citrate were 15 g/L, 25 g/L and 5 g/L respectively, the leaching flow rate was 0.50 mL/min, the pH value was approximatively 7.00 and the leaching temperature was 293 K to 303 K. At these conditions, the mass transfer efficiencies of three ammonium carboxylates for rare earth and aluminum was in the order of ammonium acetate > ammonium tartrate > ammonium citrate. Moreover, the ammonium acetate could commendably inhibit aluminum ions entering the lixivium.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2021, 57, 4; 48-62
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The intensified effect of nitrogen removal properties using Pseudomonas fulva K3 and MgBC for the weathered crust rare earth wastewater treatment
    Autorzy:
    Deng, Xiangyi
    Chi, Ruan
    Xiao, Chunqiao
    Zhang, Zhenyue
    Liu, Xuemei
    Hu, Jingang
    Powiązania:
    https://bibliotekanauki.pl/articles/1447385.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    weathered crust rare earth wastewater
    nitrogen removal
    pseudomonas fulva K3
    magnesium-modified biochar
    intensified effect
    Opis:
    A new bacteria named Pseudomonas fulva K3 (P. fulva) strain was isolated from the surroundings of weathered crust rare earth tailing with efficient NH4+-N removal ability via heterotrophic nitrification and aerobic denitrification. The nitrogen removal properties could be intensified by the synergistic effect between as-prepared magnesium-modified biochar (MgBC) and P. fulva strain. The results show that P. fulva exhibited a rod-shaped morphology and $NH_4+-N$ can be completely biodegraded under the optimal conditions of pH=7.0~8.0, temperature 30 oC and initial $NH_4+-N$ concentration of 100 ~150 mg/L. The $NH_4+-N$ tolerant concentration for P. fulva was determined to be 300 mg/L. The magnesium-modified biochar (MgBC) worked as an adsorbent of $NH_4+-N$. The kinetics and isotherm model for adsorption could be described by the pseudo-secondorder kinetic and Freundlich model, respectively. The XPS results showed that $NH_4+-N$ was mainly adsorbed on the surface by chemical adsorption. Furthermore, the P. fulva could be immobilized on MgBC due to its large surface area, adjusting the concentration of $NH_4+-N$ to a proper range for the growth of P. fulva by adsorption and desorption equilibrium, and leading to the intensified effect on nitrogen removal. The total nitrogen removal efficiency of the eluted weathered crust rare earth tailing reached 84.7 % in MgBC + P. fulva system.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2021, 57, 3; 84-96
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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