Structure characterization and grinding performance of gas-quenched steel slag abrasive

The low utilization rate of steel slag in China has exposed serious environmental and social problems. In the present work, the basic oxygen furnace (BOF) slag was modified by blast furnace (BF) slag and then beaded by the means of gas quenching. The gas-quenching rate, bead formation rate, physical properties, microscopic characteristics and free lime (f-CaO) of gas-quenched slag beads were analyzed to broaden the utilization of BOF slag. The results show that the more BF slag is added, the higher the gas-quenching rate is, and the lower the bead formation rate becomes. When no BF slag is added, the beads are mainly composed of magnetite, limonite and melilite. After BF slag is added, a large amount of glass phase and a little amount of Ca2SiO4 and MgO are found in beads. The content of f-CaO beads decreases after the modified slag is gas quenched at high temperature. Moreover, the more BF slag is added, the higher the elimination rate of f-CaO becomes. Considering the industry standard of steel slag sand in China as well as the gas-quenching rate, physical and chemical properties, the gas-quenched steel slag beads with 5 and 15% BF slag better meet the medium sand standard, which can be used as fine aggregate.

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Characterization of microwave-sintered ceramic composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151519 ◽

1993 ◽

Vol 51 ◽

pp. 1136-1137

Author(s):

X. Zhang ◽

Y. Pan ◽

T.T. Meek

Keyword(s):

Matrix Material ◽

Maximum Output Power ◽

Ceramic Matrix Composite ◽

Ceramic Composites ◽

Processing Technique ◽

Structure Characterization ◽

Alumina Powder ◽

Maximum Output ◽

Sintered Ceramic

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

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Structure characterization of ground calcium carbonate flocs by fractal analysis and their effects on handsheet properties

TAPPI Journal ◽

10.32964/tj12.3.17 ◽

2013 ◽

Vol 12 (3) ◽

pp. 17-23 ◽

Cited By ~ 3

Author(s):

WANHEE IM ◽

HAK LAE LEE ◽

HYE JUNG YOUN ◽

DONGIL SEO

Keyword(s):

Fractal Analysis ◽

Structural Characteristics ◽

Fractal Dimensions ◽

Strength Loss ◽

Structure Characterization ◽

Uniform Size ◽

Cross Sectional ◽

Floc Size ◽

Mass Fractal ◽

Handsheet Properties

Preflocculation of filler particles before their addition to pulp stock provides the most viable and practical solution to increase filler content while minimizing strength loss. The characteristics of filler flocs, such as floc size and structure, have a strong influence on preflocculation efficiency. The influence of flocculant systems on the structural characteristics of filler flocs was examined using a mass fractal analysis method. Mass fractal dimensions of filler flocs under high shear conditions were obtained using light diffraction spectroscopy for three different flocculants. A single polymer (C-PAM), a dual cationic polymer (p-DADMAC/C-PAM) and a C-PAM/micropolymer system were used as flocculants, and their effects on handsheet properties were investigated. The C-PAM/micropolymer system gave the greatest improvement in tensile index. The mass fractal analysis showed that this can be attributed to the formation of highly dense and spherical flocs by this flocculant. A cross-sectional analysis of the handsheets showed that filler flocs with more uniform size were formed when a C-PAM/micropolymer was used. The results suggest that a better understanding of the characteristics of preflocculated fillers and their influence on the properties of paper can be gained based on a fractal analysis.

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