scholarly journals Dynamic pore structure evolution of the ion adsorbed rare earth ore during the ion exchange process

2019 ◽  
Vol 6 (11) ◽  
pp. 191107 ◽  
Author(s):  
Lingbo Zhou ◽  
Xiaojun Wang ◽  
Yulong Zhuo ◽  
Kaijian Hu ◽  
Wen Zhong ◽  
...  
Keyword(s):  
Rare Earth ◽  
Ion Exchange ◽  
Pore Structure ◽  
Exchange Process ◽  
Structure Evolution ◽  
Seepage Rate ◽  
Leaching Process ◽  
Ion Exchange Process ◽  
Ore Body ◽  
Leaching Solution

During the leaching process of the ion-adsorbed rare earth (RE) ore, the pore structure evolution of the ore body plays a vital role in the seepage of the leaching solution. To investigate the evolution of the pore structure during the leaching process, experiments have been carried out with remodelled RE ore samples based on the physical characteristics of in situ ores. The seepage rate difference between deionized water leaching solution and 2% NH 4 Cl leaching solution during the active leaching period was analysed. The porosity and the dynamic pore size evolution of pore structures in the ore body are discussed. Results indicate that along with ion exchange between the RE ore and the leaching solution, the porosity of the sample remains constant and the pore structure shows a decreasing trend in the first part and an increasing trend in the second part. Specifically, during the ion exchange process, the number of minimal pores (0–5 µm), small pores (5–10 µm) and medium pores (10–25 µm) increases significantly and the number of medium–large pores (25–60 µm), large pores (60–120 µm) and mega pores (greater than 120 µm) decreases dramatically. Along with the completion of the ion exchange process, the evolution of porous structure shows an opposite trend. The mechanism study reveals that the evolution of pore structure is induced by the difference of ionic strength in the leaching solution during the ion exchange process, where the RE ore microparticles will be absorbed or desorbed on to the solid phase.

A two-parameter model for ion exchange process of ion-adsorption type rare earth ores

2020 ◽  
Vol 38 (11) ◽  
pp. 1251-1256
Author(s):  
Ping Long ◽  
Guanshi Wang ◽  
Chao Zhang ◽  
Ying Huang ◽  
Sihai Luo
Keyword(s):  
Rare Earth ◽  
Ion Exchange ◽  
Exchange Process ◽  
Ion Adsorption ◽  
Ion Exchange Process ◽  
Two Parameter

scholarly journals Experimental Research on the Impact of Ion Exchange and Infiltration on the Microstructure of Rare Earth Orebody

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaojun Wang ◽  
Yulong Zhuo ◽  
Shuqiang Deng ◽  
Yongxin Li ◽  
Wen Zhong ◽  
...  
Keyword(s):  
Rare Earth ◽  
Ion Exchange ◽  
Pore Structure ◽  
Pore Size ◽  
Size Structure ◽  
Impact Factors ◽  
Leaching Process ◽  
Structure Changes ◽  
The Impact ◽  
Sole Action

To detect the evolutional characteristics of pore structure in ore leaching process of ion-type rare earth, this paper analyzes the influence mechanism of ion exchange seepage action on the microstructure of orebody, and an experiment for remodeling rare earth saturated samples and ore leaching was designed. Using nuclear magnetic resonance technology obtains the pore structure T2 map of H2O and (NH4)2SO4 solution in the ore leaching process and inverts and reconstitutes the pore structure distribution image. The results of contrastive analysis experiments indicate that impact factors of the ore leaching process on the microstructure of rare earth orebodies include two aspects: solution seepage and ion exchange. The main factor of pore structure distribution is the ion exchange action, determined by a dual effect. The sole action of solution seepage leads to an increase in pore size, which means that pore size structure is changing from small and medium to macro. Ion exchange gives rise to the movement and restructuring of particles, which results in a decrease in pore sizes. The pore structure changes from loose to compact; in the entire ore leaching process, the ion exchange action advances in a layered shape along the direction of seepage, and the chemical replacement and physical seepage alternately impact the microstructure of the orebodies.

Removal of Toxic Dyestuffs from Aqueous Solution by Amphoteric Bioadsorbent

2020 ◽  
Vol 16 ◽  
Author(s):  
Reda M. El-Shishtawy ◽  
Abdullah M. Asiri ◽  
Nahed S. E. Ahmed
Keyword(s):  
Aqueous Solution ◽  
Ion Exchange ◽  
Dye Removal ◽  
Exchange Process ◽  
Cationic Dyes ◽  
Carboxyl Groups ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Isotherm ◽  
Ion Exchange Process ◽  
Dyes And Pigments

Background: Color effluents generated from the production industry of dyes and pigments and their use in different applications such as textile, paper, leather tanning, and food industries, are high in color and contaminants that damage the aquatic life. It is estimated that about 105 of various commercial dyes and pigments amounted to 7×105 tons are produced annually worldwide. Ultimately, about 10–15% is wasted into the effluents of the textile industry. Chitin is abundant in nature, and it is a linear biopolymer containing acetamido and hydroxyl groups amenable to render it atmospheric by introducing amino and carboxyl groups, hence able to remove different classes of toxic organic dyes from colored effluents. Methods: Chitin was chemically modified to render it amphoteric via the introduction of carboxyl and amino groups. The amphoteric chitin has been fully characterized by FTIR, TGA-DTG, elemental analysis, SEM, and point of zero charge. Adsorption optimization for both anionic and cationic dyes was made by batch adsorption method, and the conditions obtained were used for studying the kinetics and thermodynamics of adsorption. Results: The results of dye removal proved that the adsorbent was proven effective in removing both anionic and cationic dyes (Acid Red 1 and methylene blue (MB)), at their respective optimum pHs (2 for acid and 8 for cationic dye). The equilibrium isotherm at room temperature fitted the Freundlich model for MB, and the maximum adsorption capacity was 98.2 mg/g using 50 mg/l of MB, whereas the equilibrium isotherm fitted the Freundlich and Langmuir model for AR1 and the maximum adsorption capacity was 128.2 mg/g. Kinetic results indicate that the adsorption is a two-step diffusion process for both dyes as indicated by the values of the initial adsorption factor (Ri) and follows the pseudo-second-order kinetics. Also, thermodynamic calculations suggest that the adsorption of AR1 on the amphoteric chitin is an endothermic process from 294 to 303 K. The result indicated that the mechanism of adsorption is chemisorption via an ion-exchange process. Also, recycling of the adsorbent was easy, and its reuse for dye removal was effective. Conclusion: New amphoteric chitin has been successfully synthesized and characterized. This resin material, which contains amino and carboxyl groups, is novel as such chemical modification of chitin hasn’t been reported. The amphoteric chitin has proven effective in decolorizing aqueous solution from anionic and cationic dyes. The adsorption behavior of amphoteric chitin is believed to follow chemical adsorption with an ion-exchange process. The recycling process for few cycles indicated that the loaded adsorbent could be regenerated by simple treatment and retested for removing anionic and cationic dyes without any loss in the adsorbability. Therefore, the study introduces a new and easy approach for the development of amphoteric adsorbent for application in the removal of different dyes from aqueous solutions.

Chromate ion-exchange process at alkaline pH

1986 ◽  
Vol 20 (9) ◽  
pp. 1177-1184 ◽  
Author(s):  
Arup K. Sengupta ◽  
Dennis Clifford ◽  
Suresh Subramonian
Keyword(s):  
Ion Exchange ◽  
Exchange Process ◽  
Alkaline Ph ◽  
Ion Exchange Process ◽  
Chromate Ion

The Application of ß“-Alumina As A Solid State Laser Host

1985 ◽  
Vol 60 ◽  
Author(s):  
J. D. Barrie ◽  
D. L. Yang ◽  
B. Dunn ◽  
O. M. Stafsudd
Keyword(s):  
Optical Properties ◽  
Solid State ◽  
Ion Exchange ◽  
Exchange Process ◽  
Laser Action ◽  
Solid State Laser ◽  
Host Crystal ◽  
State Laser ◽  
Ion Exchange Process ◽  
Single Host

AbstractIon exchanged ß“-aluminas display a number of interesting optical properties which suggest that the material is well suited for application as a solid state laser host. Small platelets of Nd3+ Ion exchanged β“-alumina exhibit laser action with gain coefficients many times greater than YAG. The versatility of the ion exchange process enables one to form a wide variety of compounds with different active ions and concentrations, thereby allowing the study of many different effects within a single host crystal.

Removal of Se(VI) from Raw Water by Ion Exchange Process

2012 ◽  
Vol 430-432 ◽  
pp. 941-948 ◽  
Author(s):  
Yong Sheng Shi ◽  
Yu Zhen Shi ◽  
Lin Wang
Keyword(s):  
Ion Exchange ◽  
Removal Rate ◽  
Exchange Process ◽  
Selenium Concentration ◽  
Quality Standard ◽  
Raw Water ◽  
Strong Base ◽  
Ion Exchange Process ◽  
Efficiency Cost ◽  
Easy Operation

Studies have been carried out on removal of Se(Ⅵ) from raw water by ion exchange process. The experiment results indicate that employment of strong-base anion exchange resin of 201×7 can receive a desirable result for Se removal. It is particularly true that the removal rate of Se(Ⅵ) can achieve more than 96% when the Se(Ⅵ) concentration in raw water is 100μg/L. This allows selenium concentration of the supply water in full conformity to the quality standard currently available for drinking water. Ion exchange process for Se removal has been proved to be competent for its efficiency, cost effectiveness and easy operation.

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