Value Recovery from Phosphate Mining and Processing Tailings & Byproducts

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Processing and Extractive Metallurgy".

Deadline for manuscript submissions: closed (31 May 2022) | Viewed by 8079

Special Issue Editors


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Guest Editor
Florida Industrial and Phosphate Research Institute, Florida Polytechnic University, Bartow, FL 33830, USA
Interests: phosphate processing; mineral beneficiation; rare earths recovery; metallurgical engineering

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Guest Editor
School of Resources and Safety Engineering, Wuhan Institute of Technology, Wuhan 430073, China
Interests: rare earth minerals processing and hydrometallurgy; geochemistry of rare earths; separation engineering

Special Issue Information

Dear Colleagues,

Phosphate ore is not only the source of an essential nutrient (P) for plant growth, but it also contains substantial amounts of elements critical to developing green energy for the future. Uranium in phosphate deposits account for 88% of the unconventional U resources, while rare earth elements (REEs) in phosphate deposits represent hundreds of years of current world demand for these vital elements. Large portions of those valuable elements in phosphate ore end up in several phosphate mining and processing tailings, waste streams, or byproducts, including waste clay from washing, flotation tails, phosphogypsum, phosphoric acid sludge, and process water. A tremendous amount of phosphorus is also tied up with the tailings, particularly with the waste clay, flotation tails and phosphogypsum. Other valuable elements in those streams include Mg, F, I, CaO, and SiO2. This Special Issue welcomes quality research papers on the recovery of one or more of those values from any of the streams described above.

Dr. Patrick Zhang
Prof. Dr. Ru-an Chi
Guest Editors

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Keywords

  • phosphate tailings
  • phosphate
  • phosphoric acid sludge
  • phosphogypsum
  • phosphate (phosphatic) clay
  • rare earths
  • comprehensive recovery

Published Papers (3 papers)

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Research

14 pages, 3247 KiB  
Article
Removal of Fluoride from Phosphogypsum Leaching Solution with Phosphate Tailing Based Layered Double Hydroxides: Kinetics and Equilibrium Isotherms
by Yanming Liu, Han Zhang, Dunquan Xiao, Hanjun Wu, Zhenyue Zhang, Lulu Xu, Qingrong Cheng, Hong Zhou, Junxia Yu, Zhiquan Pan and Dongsheng Wang
Minerals 2022, 12(7), 858; https://doi.org/10.3390/min12070858 - 5 Jul 2022
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Abstract
In this work, ternary and quaternary layered double oxides (PTB-LDO3 and PTB-LDO4) based on phosphate tailings were synthesized by the coprecipitation method. The as-prepared samples were characterized and applied to remove fluorine ions from a phosphogypsum leaching solution. The results indicated that both [...] Read more.
In this work, ternary and quaternary layered double oxides (PTB-LDO3 and PTB-LDO4) based on phosphate tailings were synthesized by the coprecipitation method. The as-prepared samples were characterized and applied to remove fluorine ions from a phosphogypsum leaching solution. The results indicated that both the precursor of PTB-LDO3 and PTB-LDO4 showed a layered structure with characteristic diffraction peaks of hydrotalcite. Compared with PTB-LDO4, PTB-LDO3 exhibited better adsorption performance at pH 5–6 and a dosage of 0.04 mg L−1. The adsorption kinetics results revealed that the adsorption of fluorine by PTB-LDO3 and PTB-LDO4 reached the adsorption equilibrium in about 3 h, and followed the pseudo-second-order model. The adsorption data could be fitted better with the Langmuir isotherm with the maximum adsorption amounts of 26.03 mg g−1 and 15.66 mg g−1 for PTB-LDO3 and PTB-LDO4, respectively. The adsorption of fluorine by PTB-LDO3 and PTB-LDO4 were both spontaneous and exothermic, and exhibited excellent reusability and stability. This study provides a possibility for the combined treatment of phosphorus chemical solid waste (phosphorus tailings) and phosphorus chemical wastewater (phosphogypsum leaching liquid). Full article
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18 pages, 6834 KiB  
Article
Characterization and Leaching Kinetics of Rare Earth Elements from Phosphogypsum in Hydrochloric Acid
by Qingjun Guan, Ying Sui, Chufeng Liu, Yongjie Wang, Chuxiong Zeng, Weijian Yu, Zhiyong Gao, Zhenyue Zang and Ru-an Chi
Minerals 2022, 12(6), 703; https://doi.org/10.3390/min12060703 - 31 May 2022
Cited by 11 | Viewed by 2363
Abstract
The characterization and leaching mechanism of REEs from phosphogypsum (PG) in HCl was studied in-depth. REEs contained in the PG were 208 ppm, of which Y, La, Ce, and Nd were the four most abundant elements. The modes of occurrence of rare earth [...] Read more.
The characterization and leaching mechanism of REEs from phosphogypsum (PG) in HCl was studied in-depth. REEs contained in the PG were 208 ppm, of which Y, La, Ce, and Nd were the four most abundant elements. The modes of occurrence of rare earth elements (REEs) in the PG were quantified using the sequential chemical extraction (SCE) method. Among the five REE occurrence species, the metal oxide form accounted for the largest proportion, followed by the residual, organic matter, and ion-exchangeable fractions, and REEs bound to carbonates were the least. From the comparison of the distributions of REEs and calcium in different occurrence states, it can be determined that REEs contained in the PG were mainly present in the residue state (existed in the gypsum lattice) and the metal oxide state (easily leached). The leaching results show that the suitable leaching conditions were acid concentration of 1.65 mol/L, S/L ratio of 1/10, and reaction temperature of 60 °C. At the condition, the maximum leaching efficiency for ∑REE was 65.6%, of which the yttrium leaching rate was the highest and reached 73.8%. Importantly, A new kinetic equation based on the cylindrical shrinking core model (SCM) was deduced and could well describe REE leaching process from PG. The apparent activation energy for ∑REE leaching was determined to be 20.65 kJ·mol−1. Full article
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12 pages, 2163 KiB  
Article
Recrystallization of Triple Superphosphate Produced from Oyster Shell Waste for Agronomic Performance and Environmental Issues
by Somkiat Seesanong, Chaowared Seangarun, Banjong Boonchom, Chuchai Sronsri, Nongnuch Laohavisuti, Kittichai Chaiseeda and Wimonmat Boonmee
Minerals 2022, 12(2), 254; https://doi.org/10.3390/min12020254 - 16 Feb 2022
Cited by 4 | Viewed by 3104
Abstract
Calcium dihydrogen phosphate monohydrate (Ca(H2PO4)2·H2O) (a fertilizer) was successfully synthesized through a recrystallization process using prepared triple superphosphate (TSP) derived from oyster shell waste as the starting material. This bio-green, eco-friendly process to produce an [...] Read more.
Calcium dihydrogen phosphate monohydrate (Ca(H2PO4)2·H2O) (a fertilizer) was successfully synthesized through a recrystallization process using prepared triple superphosphate (TSP) derived from oyster shell waste as the starting material. This bio-green, eco-friendly process to produce an important fertilizer can promote a sustainable society. The shell-waste-derived TSP was dissolved in distilled water and kept at 30, 50, and 80 °C. Non-soluble powder and TSP solution were obtained. The TSP solution fractions were then dried, and the recrystallized products (RCP30, RCP50, and RCP80) were obtained and confirmed as Ca(H2PO4)2·H2O. Conversely, the non-soluble products (NSP30, NSP50, and NSP80) were observed as calcium hydrogen phosphate dihydrate (CaHPO4·2H2O). The recrystallized yields of RCP30, RCP50, and RCP80 were found to be 51.0%, 49.6%, and 46.3%, whereas the soluble percentages were 98.72%, 99.16%, and 96.63%, respectively. RCP30 shows different morphological plate sizes, while RCP50 and RCP80 present the coagulate crystal plates. X-ray diffractograms confirmed the formation of both the NSP and RCP. The infrared adsorption spectra confirmed the vibrational characteristics of HPO42−, H2PO4, and H2O existed in CaHPO4·2H2O and Ca(H2PO4)2·H2O. Three thermal dehydration steps of Ca(H2PO4)2·H2O (physisorbed water, polycondensation, and re-polycondensation) were observed. Ca(H2PO4)2 and CaH2P2O7 are the thermodecomposed products from the first and second steps, whereas the final product is CaP2O6. Full article
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