Flotation specificity of coal gasification fine slag based on release analysis

Liu, Dinghua; Wang, Weidong; Tu, Yanan; Ren, Guanlin; Yan, Shunlong; Liu, Haiyan; He, Hao

doi:10.1016/j.jclepro.2022.132426

Cited by 40 publications

(4 citation statements)

References 34 publications

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“…N 2 was used as the adsorption medium for the pore analysis. The BET method was employed to calculate the specific surface area [40], while the BJH method was used for pore volume calculation [41]. The Raman spectra results were subjected to peak fitting, dividing them into five peaks.…”

Section: Calculation and Analysis Methodsmentioning

confidence: 99%

Experimental Study on the Thermal Reduction of CO2 by Activated Solid Carbon-Based Fuels

Zhang,

Liang,

Zhu

et al. 2024

Energies

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For achieving CO2 thermal reduction, a technology combining solid carbon activation and high-temperature CO2 reduction was proposed, named as activated-reduction technology. In this study, this technology is realized by using a circulating fluidized bed and downdraft reactor. Reduced agent parameters (O2/C and CO2 concentration) greatly affect the reduction effect of CO2. In addition, the effect of the activation process on different carbon-based materials can help to broaden the range of carbon-based materials used for CO2 reduction, which is also an important issue. The following three points have been studied through experiments: (1) the influence of the characteristics of the reduced agent (CO2 concentration and O2/C) on CO2 reduction; (2) the performance of different chars in CO2 reduction; and (3) the activation effect of solid carbon. The activation process can develop the pore structure of coal gasification char and transform it into activated char with higher reactivity. The CO concentration in the tail gas is a crucial factor limiting the effectiveness of CO2 reduction, with an experimentally determined upper limit of around 55% at 1200 °C. If CO concentration is far from the upper limit, temperature becomes the significant influencing factor. When the reduced agent O2/C is 0.18, the highest net CO2 reduction of 0.021 Nm3/kg is achieved at 60% CO2 concentration. When the reduced agent CO2 concentration is 50%, the highest net CO2 reduction of 0.065 Nm3/kg is achieved at 0.22 O2/C. Compared with CPGC, YHGC has higher reactivity and is more suitable for CO2 reduction. The activation process helps to reduce the differences between raw materials.

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Section: Calculation and Analysis Methodsmentioning

confidence: 99%

Experimental Study on the Thermal Reduction of CO2 by Activated Solid Carbon-Based Fuels

Zhang,

Liang,

Zhu

et al. 2024

Energies

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“…The potential ecological risk assessment and leaching toxicity identification of heavy metals in China's CGS are of great significance for the reasonable storage and in-depth utilization of it. Previous studies on CGS mainly focus on its particle size distribution, mineral composition and thermochemical transformation (Liu et al 2022, Hong et al 2022, Dong et al 2022, and there are few related studies on the environmental risk characteristics of CGS. studied the leaching characteristics of potentially hazardous elements from two kinds of entrained-bed CGS.…”

Section: Fig 1 Typical Gasification Processmentioning

confidence: 99%

Ecological risk assessment of heavy metals in coal gasification slags and their leaching toxicity from China

Zhang

et al. 2023

Preprint

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The coal gasification process produces a large amount of coal gasification slag (CGS), which enriches the heavy metals in the raw coal. The CGS will not only occupies land resources in the long-term storage, but also has potential ecological pollution risks. In this study, eight kinds of CGS samples from different regions of China were subjected, and their chemical composition and environmental risks were studied. Two leaching methods issued by the ministry of ecology and environment of China were used to carry out leaching experiments for evaluating the hazardous waste level of CGS. The results show that, among eight samples, the comprehensive potential ecological risk of all samples did not reach high risk, and there are two kinds of CGCS and two kinds of CGFS reach middle risk. In general, CGS is not hazardous solid wastes, most of which are Class I general industrial solid wastes, and a few are Class II general industrial solid wastes. These conclusions indicate that heavy metals in CGS have certain potential ecological risks. Under different leaching conditions, except for Be, the precipitation amount of heavy metals in CGS is basically within the limited range of relevant standards, but its environmental risks cannot be ignored.

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“…However, the enrichment of the residual carbon in the fine slag by sieving separation suffers from a significant challenge. The molten ash and residual carbon are often closely embedded, in particular, a large number of the high ash fine particles are attached on the surface of the partly gasified carbon particles . Such a unique tightly wrapped combination makes it nearly impossible to achieve an effective separation even by mechanical stirring and wet sieving, thus, leading to a high ash content in the concentrates as well a low separation efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…The molten ash and residual carbon are often closely embedded, in particular, a large number of the high ash fine particles are attached on the surface of the partly gasified carbon particles. 16 Such a unique tightly wrapped combination makes it nearly impossible to achieve an effective separation even by mechanical stirring and wet sieving, thus, leading to a high ash content in the concentrates as well a low separation efficiency. Indeed, for closely embedded minerals, the effective dissociation, cleaning and dispersion are often prerequisites for an efficient separation.…”

Section: Introductionmentioning

confidence: 99%

Enrichment of Residual Carbon in Coal Gasification Fine Slag via Wet Sieving Separation with Ultrasonic Pretreatment

Sun

Liu

et al. 2022

ACS Omega

Self Cite

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To overcome the environmental and economic challenges posed by the increasing amounts of the coal gasification slag, here, a simple and efficient method for enriching the residual carbon from the coal gasification fine slag was proposed. The residual carbon enrichment pattern in the particle size distribution of coal gasification fine slags after the ultrasonic pretreatment was mainly enriched toward the 500–250 μm and 250–125 μm particle size classes by analyzing the changes in the particle size distribution and apparent morphology. The pulp pretreatment at the ultrasonic output power of 270 W for 4 min was determined as the optimal experimental condition with respect to the yield, ash content, and ash rejection of the concentrates. Compared to the conventional wet sieving separation, the yield and ash content of the final concentrates were reduced by 7.99 and 14.96%, respectively. Moreover, the ash rejection of the final concentrates was as high as 88.51%, indicating an increment of 11.63% than the conventional wet sieving separation. Furthermore, thermogravimetric analysis confirmed that the final concentrates exhibited the lowest reactivity; however, these demonstrated had the highest carbon content (nearly 70%) with 27.27% ash content. The combustion characteristics analysis showed that the wet screening concentrate after ultrasonic pretreatment had the highest composite combustion characteristic index (S) of 3.17 × 10–8, as compared to the raw and conventional sieving concentrates.

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Flotation specificity of coal gasification fine slag based on release analysis

Cited by 40 publications

References 34 publications

Experimental Study on the Thermal Reduction of CO2 by Activated Solid Carbon-Based Fuels

Experimental Study on the Thermal Reduction of CO2 by Activated Solid Carbon-Based Fuels

Ecological risk assessment of heavy metals in coal gasification slags and their leaching toxicity from China

Enrichment of Residual Carbon in Coal Gasification Fine Slag via Wet Sieving Separation with Ultrasonic Pretreatment

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