Separation of aluminum and silica from coal gangue by elevated temperature acid leaching for the preparation of alumina and SiC

Xiao, Jin; Li, Fachuang; Zhong, Qifan; Bao, Huihui; Wang, Bingjie; Huang, Jindi; Zhang, Yanbing

doi:10.1016/j.hydromet.2015.04.018

Cited by 104 publications

(34 citation statements)

References 33 publications

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“…The flask was heated to 90 • C in magnetic stirrers and stirred for 60 min. Then the mixture was filtered and washed with deionized water for many times, the filtrate was analyzed to determine aluminum by inductively coupled plasma atomic emission spectrometer (ICP-AES), and the dissolution percentages of Al 2 O 3 were calculated [18,22]. The dissolution of Al 3+ in hydrochloric acid solution was the indicator to evaluate the activation efficiency of calcined coal gangue.…”

Section: Testing Methodsmentioning

confidence: 99%

“…The sample undergoes a series of physical and chemical variations with the increasing temperature, and these variations are: The weight loss of 1.89% is attributed to the absorbed water is liberated and the ignitable substances decompose and burn before 455.6 • C. Structural hydroxyl groups were removed from kaolinite by a reorganization of the octahedral layer of kaolinite to meta-kaolinite (Al 2 O 3 ·2SiO 2 ) as described by Equation (2), when temperature raised up to a range of 455.6~691.1 • C, resulting in weight loss of about 13.62%. percentages of Al2O3 were calculated [18,22]. The dissolution of Al 3+ in hydrochloric acid solution was the indicator to evaluate the activation efficiency of calcined coal gangue.…”

Section: Thermal Analysismentioning

confidence: 99%

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Investigation on Calcination Behaviors of Coal Gangue by Fluidized Calcination in Comparison with Static Calcination

Yuan

Han

et al. 2017

Minerals

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Abstract:In order to comprehensively utilize coal gangue, we present fluidized calcination as a new thermal technology for activating coal gangue and systematical study was conducted in comparison with static calcination. The calcined products obtained by different calcination methods under various temperatures were characterized by the means of X-ray diffraction (XRD), thermal gravimetry-differential scanning calorimeter (TG-DSC), Fourier transform-infrared spectroscopy (FT-IR) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS). Chemical and physical characteristics such as aluminium leaching rate, chemical oxygen demand and whiteness of calcined products were also investigated. The results show that aluminium leaching rate could reach to the maximal value 74.42% at 500 • C by fluidized calcination, while the maximal value of 66.33% could be reached at 600 • C by static calcination. Products by fluidized calcination obtained higher whiteness and lower chemical oxygen demand (COD) under the same calcination temperature. The well-crystallized kaolinite transform to amorphous meta-kaolinite under 600 • C and mullite presence under 1000 • C according to phase transformation, chemical bond variation and microstructure evolution analysis. Fluidized calcination was more efficiently for combustion of carbon/organic matter and dehydroxylation of kaolinite, which might applied in coal gangue industry in future.

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Section: Testing Methodsmentioning

confidence: 99%

Section: Thermal Analysismentioning

confidence: 99%

Investigation on Calcination Behaviors of Coal Gangue by Fluidized Calcination in Comparison with Static Calcination

Yuan

Han

et al. 2017

Minerals

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“…The work by [53] also resulted in the production of saleable inorganic chemical by-products such as carbon, magnetite (Fe 3 O 4 ), alumina (Al 2 O 3 ), iron oxide (Fe 2 O 3 ), iron chloride (FeCl 3 ), and cenospheres (hollow microspheres). Recent work by Xiao et al [54] has also resulted in the by-production of silicon carbide. Some of the value adding uses of CFA are shown in Table 6.…”

Section: Opportunities For a Sustainable Cfa Value Chainmentioning

confidence: 99%

Towards the Utilization of Fly Ash as a Feedstock for Smelter Grade Alumina Production: A Review of the Developments

Sibanda

Ndlovu

Dombo

et al. 2016

J. Sustain. Metall.

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The major commercial technology for the production of smelter grade alumina has conventionally been the Bayer process which converts bauxite ore, an aluminum containing ore which typically contains about 50 % Al 2 O 3 , into smelter grade alumina that contains over 99.0 % Al 2 O 3 . Another potential source of aluminum that is receiving renewed attention is coal fly ash (CFA), which is a by-product of coal combustion during electricity generation in power stations. Most coal fly ash found around the world contain typically between 25 and 35 % Al 2 O 3 , which is substantial to make CFA a potential alternative source of alumina. There has been some considerable research effort, in the last two decades, aimed at extracting aluminum from this semi-waste product. Much emphasis from the different workers has been on the leaching of the contained aluminum, while the purification and recovery of alumina from the liquor solution has received less attention. Notwithstanding that several patents on the processes to recover alumina from CFA exist, limited commercialisation of the processes has been reported. This paper seeks to review and discuss the hydrometallurgical extraction processes that have been formulated and tested by different workers and then assesses the available opportunities and the way forward on the prospects of commercially extracting alumina and other valuable components from this abundant resource.

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“…cement and brick) (Xiao et al, 2015). All these processes as the spontaneous combustion of coal gangue, are without any desulfurization equipment, and the emissions of hazardous substances have not yet been included in the statistics.…”

Section: Implications and Limitationsmentioning

confidence: 99%

Estimate of sulfur, arsenic, mercury, fluorine emissions due to spontaneous combustion of coal gangue: An important part of Chinese emission inventories

Wang

Luo

Wang

et al. 2016

Environmental Pollution

167

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a b s t r a c tA rough estimate of the annual amount of sulfur, arsenic, mercury and fluoride emission from spontaneous combustion of coal gangue in China was determined. The weighted mean concentrations of S, As, Hg, and F in coal gangue are 1.01%, 7.98, 0.18, and 365.54 mg/kg, respectively. Amounts of S, As, Hg, and F emissions from coal gangue spontaneous combustion show approximately 1.13 Mt, and 246, 45, and 63,298 tons in 2013, respectively. The atmospheric release amount of sulfur from coal gangue is more than one tenth of this from coal combustion, and the amounts of As, Hg, and F are close to or even exceed those from coal combustion. China's coal gangue production growth from 1992 to 2013 show an obvious growth since 2002. It may indicate that Chinese coal gangue has become a potential source of air pollution, which should be included in emission inventories.

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Separation of aluminum and silica from coal gangue by elevated temperature acid leaching for the preparation of alumina and SiC

Cited by 104 publications

References 33 publications

Investigation on Calcination Behaviors of Coal Gangue by Fluidized Calcination in Comparison with Static Calcination

Investigation on Calcination Behaviors of Coal Gangue by Fluidized Calcination in Comparison with Static Calcination

Towards the Utilization of Fly Ash as a Feedstock for Smelter Grade Alumina Production: A Review of the Developments

Estimate of sulfur, arsenic, mercury, fluorine emissions due to spontaneous combustion of coal gangue: An important part of Chinese emission inventories

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