Bauxite residue is the bulk solid waste generated by the alumina industry, and the environmental treatment of bauxite residue has always been a focus of attention. In this study, in the high calcium system, the bauxite residue was intensively digestion by the calcification-carbonation method, and the mole ratio of solution, the mass ratio of CaO/SiO of the digestion process were changed, so that the high-efficiency dealkalization of bauxite residue was realized and the aluminum oxide in bauxite residue was deeply extracted. The experimental results showed that the calcification process could achieve the recovery of 17.83% alumina at 260°C, reaction duration of 60 min, liquid-solid ratio = 5:1, the mass ratio of CaO/SiO = 3.5, and 200 g/L NaOH solution. The whole process can recover 49.61% of alumina from bauxite residue, and 94.4% of alkali in bauxite residue can be removed.
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http://dx.doi.org/10.1007/s00128-022-03554-y | DOI Listing |
Chemosphere
December 2024
College of Land Science and Technology, China Agricultural University, Beijing, 100193, PR China. Electronic address:
Heavy metals released from metallic sulfidic tailings pose significant environmental threats by contaminating surface and groundwater in mining areas. Sustainable rehabilitation methods are essential to remove or stabilize these metals, improving the quality of acid mine drainage and minimizing pollution. This study examines the adsorption capacity of zinc ions (Zn) by different iron-silicate mineral groups under natural weathering and bacteria-regulated weathered conditions.
View Article and Find Full Text PDFACS Omega
December 2024
Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Application, School of Chemistry and Environmental Science, Xiangnan University, Chenzhou 423000, China.
To immobilize the activity and bioavailability of soil Cd, the single treatment only flooding (F) and the combined treatments with flooding plus bauxite residue (F-B) or lime (F-L) were designed to investigate the impacts of different treatments on the toxicity and bioavailability of Cd in contaminated soil. Compared with the single treatment (F), the combined treatments (F-B and F-L) improved soil-associated organic functional groups and aggregated stability in soil. The average particle sizes of soil aggregates increased from 126 nm (F-treated soil) to 256 and 270 nm following F-B and F-L treatments, respectively.
View Article and Find Full Text PDFJ Hazard Mater
November 2024
Department of Civil and Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea. Electronic address:
Bioresour Technol
November 2024
FPInnovations, 2665 East Mall, Vancouver, BC V6T 1Z4, Canada.
Biomass gasification as a renewable energy technology has been a widely explored research and development area. The efficient and economic removal of harmful components, particularly tars, in raw syngas from the biomass gasifier is still a major challenge. In this study, a novel two-stage fluidized bed pilot-scale gasifier has been developed to enhance the steam-oxygen biomass gasification to generate low-tar syngas; while, a prototype hot syngas cleanup system has been designed, built and tested to further reduce the tar content and purify the syngas from the biomass gasifier for downstream applications.
View Article and Find Full Text PDFSci Rep
November 2024
Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, 31621, Dhahran, Saudi Arabia.
This study aims to reach a sustainable solution for waste management of medical plastics through value-added product extraction. It uses the DOE technique to examine the effect of natural zeolite and synthetic AlO and SiO as catalysts. A small lab-scale pyrolysis setup was used for medical plastic waste management treatment.
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