Calcination-carbonization two-step process to improve the brightness of fly ash and its application in paper filling

2019 ◽  
Vol 34 (1) ◽  
pp. 59-66
Author(s):  
Hui-ming Fan ◽  
Gao-peng Zhu ◽  
Ya-nan Qi ◽  
Jian-an Liu
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Magnetic Particles ◽  
Unburned Carbon ◽  
Key Factors ◽  
Step Method ◽  
Carbonation Reaction ◽  
Carbon Particles ◽  
Composite Filler ◽  
High Temperature Calcination

Abstract Chromogenic sources such as carbon particles and magnetic particles are the key factors restricting the brightness of fly ash. This study explored the feasibility of calcination-carbonation two-step method to improve the brightness of fly ash and apply it to paper filling. The results show that Under the condition of high temperature, the unburned carbon particles in fly ash are removed, and the brightness of fly ash is increased from 30 %ISO to 49 %ISO with the increase of burning loss. The dense calcium carbonate coating can be formed on the surface of fly ash particles modified by the carbonation reaction process after high temperature calcination, and the brightness of fly ash can be further raised to about 66 %ISO. The composite filler prepared by two-step method can be used to paper filling, the brightness of the paper can reach 76 % ISO, and it has good opacity at 20 % filling. Therefore, it is feasible to prepare fly ash-based composite filler by calcining-carbonization method.

Investigation of unburned carbon particles in fly ash by means of laser light scattering

2010 ◽  
Vol 102 (2) ◽  
pp. 357-365 ◽  
Author(s):  
R. Q. Iannone ◽  
R. Morlacchi ◽  
R. Calabria ◽  
P. Massoli
Keyword(s):  
Fly Ash ◽  
Light Scattering ◽  
Laser Light ◽  
Laser Light Scattering ◽  
Unburned Carbon ◽  
Carbon Particles

scholarly journals Magnetite and Carbon Extraction from Coal Fly Ash Using Magnetic Separation and Flotation Methods

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 320 ◽  
Author(s):  
Dmitry Valeev ◽  
Irina Kunilova ◽  
Alexander Alpatov ◽  
Alika Varnavskaya ◽  
Dianchun Ju
Keyword(s):  
Fly Ash ◽  
Magnetic Separation ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Carbon Surface ◽  
Unburned Carbon ◽  
Magnetic Fraction ◽  
Carbon Particles

In this study, enrichment methods for coal fly ash (CFA) from Omsk thermal power station No. 4 (TPS-4) were investigated. The magnetite and unburned carbon concentrates were obtained by magnetic separation and flotation methods. The wet magnetic separation used in the study increased the magnetite content in the magnetic fraction from 10.48 to 12.72 wt % compared to dry magnetic separation. The XRD analysis showed that the magnetic fraction primarily consists of magnetite, mullite, and quartz. The SEM analysis demonstrated that magnetite is located primarily on the surface of alumosilicate spheres and has three types of shape: dendritic structures, hexagonal bulk agglomerates, and star-like structures. For the flotation tests, a low-price diesel was used as the collector. It was found that, if CFA particles of 40–71 µm are used, ~99% of unburned carbon can be recovered. It was also found by SEM that, if CFA particles of 71–100 µm are used, alumosilicates on a carbon surface prevent complete interaction of diesel with carbon particles and decrease thereby carbon recovery to 83%.

HAYNES STELLITE ALLOY No. 4

Alloy Digest ◽  
1969 ◽  
Vol 18 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Cast Alloy ◽  
Heat Treating ◽  
Carbon Particles ◽  
Stellite Alloy ◽  
Temperature Performance ◽  
Cobalt Base

Abstract Haynes Stellite No. 4 is a cobalt-base cast alloy recommended for handling severe conditions of abrasion, heat and corrosion. It is especially recommended to resist the severe abrasive and corrosive action of manganese dioxide, carbon particles, and ammonium and zinc chlorides in the battery mix used in the manufacture of dry batteries. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as heat treating, machining, and joining. Filing Code: Co-59. Producer or source: Union Carbide Materials Systems Division.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

In-situ reaction between arsenic/selenium and minerals in fly ash at high temperature during blended coal combustion

2020 ◽  
Vol 48 (11) ◽  
pp. 1356-1364
Author(s):  
Jun HAN ◽  
Yang-shuo LIANG ◽  
Bo ZHAO ◽  
Zi-jiang XIONG ◽  
Lin-bo QIN ◽  
...  
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Coal Combustion ◽  
In Situ Reaction ◽  
Blended Coal

scholarly journals Fly Ash Utilisation in Mullite Fabrication: Development of Novel Percolated Mullite

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Pramod Koshy ◽  
Naomi Ho ◽  
Vicki Zhong ◽  
Luisa Schreck ◽  
Sandor Alex Koszo ◽  
...  
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Mineral Resources ◽  
Nucleating Agent ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Stable Phase ◽  
Power Stations ◽  
Firing Shrinkage

Fly ash is an aluminosilicate and the major by-product from coal combustion in power stations; its increasing volumes are major economic and environmental concerns, particularly since it is one of the largest mineral resources based on current estimates. Mullite (3Al2O3·2SiO2) is the only stable phase in the Al2O3-SiO2 system and is used in numerous applications owing to its high-temperature chemical and mechanical stabilities. Hence, fly ash offers a potential economical resource for mullite fabrication, which is confirmed by a review of the current literature. This review details the methodologies to utilise fly ash with different additives to fabricate what are described as porous interconnected mullite skeletons or dense mullite bodies of approximately stoichiometric compositions. However, studies of pure fly ash examined only high-Al2O3 forms and none of these works reported long-term, high-temperature, firing shrinkage data for these mullite bodies. In the present work, high-SiO2 fly ashes were used to fabricate percolated mullite, which is demonstrated by the absence of firing shrinkage upon long-term high-temperature soaking. The major glass component of the fly ash provides viscosities suitably high for shape retention but low enough for ionic diffusion and the minor mullite component provides the nucleating agent to grow mullite needles into a direct-bonded, single-crystal, continuous, needle network that prevents high-temperature deformation and isolates the residual glass in the triple points. These attributes confer outstanding long-term dimensional stability at temperatures exceeding 1500 °C, which is unprecedented for mullite-based compositions.

scholarly journals An Experimental Study on the Melting Solidification of Municipal Solid Waste Incineration Fly Ash

2021 ◽  
Vol 13 (2) ◽  
pp. 535
Author(s):  
Jing Gao ◽  
Tao Wang ◽  
Jie Zhao ◽  
Xiaoying Hu ◽  
Changqing Dong
Keyword(s):  
Heavy Metals ◽  
High Temperature ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Liquid Slag ◽  
Melting Process ◽  
Waste Incineration ◽  
Municipal Solid Waste Incineration ◽  
Mswi Fly Ash

Melting solidification experiments of municipal solid waste incineration (MSWI) fly ash were carried out in a high-temperature tube furnace device. An ash fusion temperature (AFT) test, atomic absorption spectroscopy (AAS), scanning electron microscope (SEM), and X-ray diffraction (XRD) were applied in order to gain insight into the ash fusibility, the transformation during the melting process, and the leaching behavior of heavy metals in slag. The results showed that oxide minerals transformed into gehlenite as temperature increased. When the temperature increased to 1300 °C, 89 °C higher than the flow temperature (FT), all of the crystals transformed into molten slag. When the heating temperatures were higher than the FT, the volatilization of the Pb, Cd, Zn, and Cu decreased, which may have been influenced by the formation of liquid slag. In addition, the formation of liquid slag at a high temperature also improved the stability of heavy metals in heated slag.

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