title: Study on dealkalization and settling performance of red mud.
abstract: At present, the dealkalization and comprehensive utilization of red mud is a worldwide problem. Studies on the settling performance and phase transformation of red mud by HCl, CaO, and H2O leaching are limited. In this study, the characteristics of red mud were systematically analyzed. The average sizes of graded and initial red mud were 4.11 and 9.20 μm, respectively. X-ray diffraction (XRD), X-ray fluorescence spectra (XRF), and thermogravimetry-differential scanning calorimetry (TG-DSC) results indicated the different mineralogical phases, composition, and thermal behavior. The addition of HCl could neutralize the alkalization in the red mud slurry, and CaO could replace the Na and K. Notably, the pH of the red mud slurry had no obvious change with the increase in water washing times in a certain pH. Interestingly, soluble Al and Fe were not detected in the HCl-red mud and CaO-red mud. In addition, the settling ratio was used to express the settling performance of the red mud slurry. Their interaction mechanisms were proposed, which may include phase transformation and the changing of the size and surface area. The research provided a better understanding of the phase transformation and settling performance in the treatment of red mud by HCl, CaO, and H2O leaching.
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Muxi
authors: M
authors: Luo
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Xuejiao
authors: X
authors: Qi
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Yurui
authors: Y
authors: Zhang
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Yufei
authors: Y
authors: Ren
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Jiacheng
authors: J
authors: Tong
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Zining
authors: Z
authors: Chen
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Yiming
authors: Y
authors: Hou
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Nuerxiate
authors: N
authors: Yeerkebai
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China. hongtao@tongji.edu.cn.
authors: Hongtao
authors: H
authors: Wang
authors: Department of Geotechnical Engineering, Tongji University, Shanghai, 200092, China. fsjgly@tongji.edu.cn.
authors: Shijin
authors: S
authors: Feng
authors: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
authors: Fengting
authors: F
authors: Li
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D004787:Environmental Pollution; D006851:Hydrochloric Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010087:Oxides / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D013818:Thermogravimetry; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D017610:Calcium Compounds; D010087:Oxides; D012987:Soil; D014867:Water; C016538:lime; D006851:Hydrochloric Acid
keywords: Dealkalization; Mineralogical phases; Phase transformation; Red mud; Settling ratio; Size distribution