The Effect of MgO-Al2O3 Spinel on Refractory Bricks Made from Al2O3-Cr2O3 Slag

2011 ◽  
Vol 291-294 ◽  
pp. 1795-1799 ◽  
Author(s):  
Li Jun Zheng ◽  
Guo Dong Zhang ◽  
Dian Li Qu ◽  
Feng Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Shock Resistance ◽  
Maximum Size ◽  
Raw Material ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance ◽  
Refractory Bricks ◽  
Scanning Electron

The Al2O3-Cr2O3 slag as raw material was analyzed by scanning electron microscopy (SEM). The effects of different size distribution of MgO-Al2O3 spinel grain on physical properties of refractory bricks made from Al2O3-Cr2O3 slag was studied according to YB/T376.1-1995（water quenching）, GB/T 5072－1985, GB/T 2997-1982 criterion. The results show that the main crystal phase of the refractory bricks were chromium corundum, corundum. The refractory bricks containing 10 wt% of the maximum size of 3.0 mm of MgO-Al2O3 spinel grain can significantly improve the thermal shock resistance of this refractory bricks. At the meanwhile, This kind of refractory bricks can be absolutely satisfied with the requirements about cold crushing strength, bulk density and apparent porosity.

Optimizing Performance of Magnesia-Spinel Brick Used at Cement Rotary Kiln

2011 ◽  
Vol 250-253 ◽  
pp. 588-594 ◽  
Author(s):  
Dong Wang ◽  
Yong Li ◽  
Yang Li ◽  
Rui Li ◽  
Yue Li
Keyword(s):  
Grain Size ◽  
Thermal Shock ◽  
Rotary Kiln ◽  
Thermal Shock Resistance ◽  
Raw Material ◽  
Crushing Strength ◽  
Magnesia Spinel ◽  
Cold Crushing Strength ◽  
Comprehensive Performance ◽  
Shock Resistance

Using high pure magnesia and magnesia-spinel as the main raw material, keeping the same quantity of spinel, specimens were made with different spinel size distribution (≤0.044mm, 1-0mm, 2-1mm, 3-2mm and 3-1mm). Dextrin and brine are the binder. Specimens were dried at the temperature of 110°C for 24 hours, sintered at the temperature of 1680°C holding 8 hours in a tunnel kiln. The properties and microstructure of the specimens were analyzed. The results are shown that the addition of spinel with grain size of 3-1mm improves sintering of magnesia-spinel brick, with the thermal shock resistance reaching 18 cycles, the cold crushing strength reaching 54 MPa, improving the comprehensive performance of the magnesia-spinel brick.

Preliminary Preparation and Characterization Studies of Cellulose from Merbau (Intsia bijuga)

2012 ◽  
Vol 620 ◽  
pp. 314-319
Author(s):  
Nur Amira Mamat Razali ◽  
Fauziah Abdul Aziz ◽  
Saadah Abdul Rahman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Alkaline Treatment ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Preliminary Preparation ◽  
Characterization Studies ◽  
Scanning Electron

Hardwood is wood from angiosperm trees. The characteristic of hardwood include flowers, endosperm within seeds and the production of fruits that contain the seeds. This paper aims to discuss the preparation and characterization of cellulose obtained from hardwood. The hardwood Merbau (Intsia bijuga) was chosen as raw material in this study. Alkaline treatment and delignification methods were used for the preparation of cellulose. Acid hydrolysis was employed to produce cellulose nanocrystal (CNC). The treated and untreated samples were characterized using x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The final product, from both trated and untreated samples were then compared.

Influence of Silicon Nitride on Properties of Corundum Based Castable

2013 ◽  
Vol 634-638 ◽  
pp. 2358-2361
Author(s):  
Jun Cong Wei ◽  
Li Rong Yang
Keyword(s):  
Electron Microscopy ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Cold Strength ◽  
X Ray ◽  
Refractory Castables ◽  
Shock Resistance ◽  
Scanning Electron

The effects of Si3N4 addition on the room temperature physical properties and thermal shock resistance properties of corundum based refractory castables were investigated using brown corundum, white corundum and alumina micropowder as the starting materials and pure calcium aluminate as a binder. The phase composition, microstructure, mechanical properties of corundum based castables were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that as the increase in Si3N4 addition, the bulk density decreased and apparent porosity increased, the cold strength deduced. However, the residual strength rate increased. That is, the thermal shock resistance was improved. This is because even though the introduction of Si3N4 inhibited the sintering of material and deduced the compactness, microcracks were produced in the materials due to a difference in thermal expansion coefficient. So the thermal shock resistance of corundum based castable was improved.

scholarly journals Influence of an addition amount of a new type of alumina on the properties of ramming mullite-corundum mixes and samples from them

2020 ◽  
Vol 120 ◽  
pp. 66-82
Author(s):  
V. V. Primachenko ◽  
I. G. Shulik ◽  
I. V. Khonchik ◽  
T. G. Tishina
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Chemical Properties ◽  
Size Composition ◽  
Synthesis Process ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance ◽  
Spherical Alumina ◽  
Addition Amount

Effect investigation of an addition amount of spherical alumina on the properties of ramming mullite-corundum mixes of the MMK-90 (on a binder of an aqueous solution of orthophosphoric acid) and MMKPBF (with a MgO addition on a borophosphate binder) brands, as well as samples from them, have been carried out. As a result of the carried out studies, it was found that the use of an optimal amount (4 %) of spherical alumina in the composition of ramming mullite-corundum mixes provides an increase in by 30 % in the cold crushing strength of samples made from them, fired at a temperature of 1580 °C, while maintaining at sufficiently high level indicators of their thermal shock resistance and slag resistance. The indicated alumina use in the composition of the MMK-90 mix during high-temperature firing of samples leads to an intensification of the mullite synthesis process. In fired samples from the MMKPBF mix, the spherical alumina forms a dense intergrowth of "felt-like" structure, which reinforces the structure, increasing the strength and thermal shock resistance of the samples. Indicators of physical and chemical properties of ramming mullite-corundum mixes of improved composition and samples made from them (for MMK-90 and MMKPBF mixes, respectively): chemical composition, wt. %: Al2O3 — not less than 90.0 and 85.0; SiO2 — within 3.2-5.0 and no more than 2.5; Fe2O3 — no more than 1.0 and 0.6; P2O5 — in the range of 2.5-3.5 and 0.5-1.0; grain size composition, mm — 3-0; cold crushing strength after firing at a temperature of 1580 °С — 110 and 70 N/mm2; thermal shock resistance — > 20 thermal cycles 950 °С — water. Ramming mullite-corundum mixes of improved composition are recommended for use in various heating units with high specific mechanical loads on the lining.

Preparation of Expanded Graphite Using Recycling Graphite Rods by Microwave Irradiation

2012 ◽  
Vol 610-613 ◽  
pp. 2356-2360
Author(s):  
Hong Liang Hua ◽  
Yun Wang ◽  
Yu Jia Wang ◽  
Shi Jun Ruan ◽  
Chao Zeng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Potassium Dichromate ◽  
Expanded Graphite ◽  
Chemical Oxidation ◽  
Raw Material ◽  
Expandable Graphite ◽  
Graphite Rods ◽  
Scanning Electron

After washing, milling and calcining, the graphite rods recycled from waste dry batteries were used as raw material to prepare expandable graphite by chemical oxidation (using acetic anhydride as inserting and potassium dichromate as oxidant), the expanded graphite was prepared from the obtained expandable graphite by microwave radiation (MW) at 1000W for 60s.The characterization of infrared spectroscopy (IR) and scanning electron microscopy (SEM) of obtained expanded graphite have been discussed. The results show that it is feasible to prepare expanded graphite using graphite rods recycled from waste dry batteries.

scholarly journals Microscopy Characterization of Silica-Rich Agrowastes to be used in Cement Binders: Bamboo and Sugarcane Leaves

2015 ◽  
Vol 21 (5) ◽  
pp. 1314-1326 ◽  
Author(s):  
Josefa Roselló ◽  
Lourdes Soriano ◽  
M. Pilar Santamarina ◽  
Jorge L. Akasaki ◽  
José Luiz P. Melges ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Saccharum Officinarum ◽  
Raw Material ◽  
Pozzolanic Reactivity ◽  
Bamboo Leaves ◽  
Bambusa Vulgaris ◽  
Microscopy Characterization ◽  
Scanning Electron

AbstractAgrowastes are produced worldwide in huge quantities and they contain interesting elements for producing inorganic cementing binders, especially silicon. Conversion of agrowastes into ash is an interesting way of yielding raw material used in the manufacture of low-CO2 binders. Silica-rich ashes are preferred for preparing inorganic binders. Sugarcane leaves (Saccharum officinarum, SL) and bamboo leaves (Bambusa vulgaris, BvL and Bambusa gigantea, BgL), and their corresponding ashes (SLA, BvLA, and BgLA), were chosen as case studies. These samples were analyzed by means of optical microscopy, Cryo-scanning electron microscopy (SEM), SEM, and field emission scanning electron microscopy. Spodograms were obtained for BvLA and BgLA, which have high proportions of silicon, but no spodogram was obtained for SLA because of the low silicon content. Different types of phytoliths (specific cells, reservoirs of silica in plants) in the studied leaves were observed. These phytoliths maintained their form after calcination at temperatures in the 350–850°C range. Owing to the chemical composition of these ashes, they are of interest for use in cements and concrete because of their possible pozzolanic reactivity. However, the presence of significant amounts of K and Cl in the prepared ashes implies a limitation of their applications.

scholarly journals EVALUATION AND CHARACTERIZATION OF GAKEM AND ABOUCHICHE CLAY SAMPLES IN BEKWARRA LGA OF CROSS RIVER STATE FOR USE AS REFRACTORY MATERIALS

2017 ◽  
Vol 36 (3) ◽  
pp. 844-848
Author(s):  
FA Ovat ◽  
DE Ewa ◽  
EA Egbe
Keyword(s):  
Bulk Density ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Linear Shrinkage ◽  
Apparent Porosity ◽  
Refractory Materials ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance

The characterization of some clay as refractory materials for furnace lining has become relevant to find solutions to the cost involved in the purchase and importation of these refractory materials. This work investigated the refractory properties of clay samples for their suitability for use in the industries. Clay samples were collected from Gakem and Abouchiche areas and analysed for physical and chemical properties to determine the suitability of the clays as refractory materials. The results showed cold crushing strength (21.46MN/m2), thermal shock resistance (27 cycles), bulk density (3.52g/cm3), linear shrinkage(3.80%), apparent porosity (28.84%) and permeability (80%) for Gakem; and cold cold crushing strength (18.40MN/m2), thermal shock resistance (25 cycles), bulk density(2.81g/cm3), linear shrinkage (3.70%), apparent porosity (25.86%) and permeability (77%) for Abouchiche respectively. The chemical compositions of these clay samples were also investigated. The results showed that the samples fall under Aluminosilicate type of clay because of their high values of Aluminium Oxide and Silicon Oxide. Tests showed that clay from these areas can be used to produce refractory materials that can withstand a furnace temperature of about 1600°C. http://dx.doi.org/10.4314/njt.v36i3.26

scholarly journals MICRO-MECHANICAL PERFORMANCE OF CONCRETE USED AS RECYCLED RAW MATERIAL IN CEMENTITIOUS COMPOSITE

2017 ◽  
Vol 13 ◽  
pp. 55 ◽  
Author(s):  
Vladimír Hrbek ◽  
Veronika Koudelková ◽  
Zdeněk Prošek ◽  
Pavel Tesárek
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Industrial Pollution ◽  
Mechanical Performance ◽  
Structural Parameters ◽  
Raw Material ◽  
Cementitious Composite ◽  
X Ray ◽  
The Impact ◽  
Scanning Electron

The reduction of industrial pollution is recently one of main goals over all fields. In civil engineering, re-cycling of structural waste provides wide opportunity contributing this effort. This paper focus on re-use of concrete waste, which after further processing can be used in new constructions as partial supplement to the mixture. To investigate the impact of re-cycled concrete addition, it is necessary to determine mechanical and structural parameters of individual phases in the “raw” material. For this purpose, grid indentation and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM, EDX) are combined to determine properties of concrete sample.

Effect of Gezawa Clay on the Properties of Silica Stone for Refractory Brick

2013 ◽  
Vol 315 ◽  
pp. 11-14 ◽  
Author(s):  
I.A. Rafukka ◽  
B. Onyekpe ◽  
Y. Tijjani
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Apparent Porosity ◽  
Chemical Compositions ◽  
Refractory Brick ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance ◽  
Made In ◽  
Fire Clay

The investigations centered on how addition of Gezawa clay (GC) affects the refractory properties of the Gezawa stone (GS) (Silica Stone) with a view to finding the optimum percentage of the blend that will give good refractory properties. The samples were crushed, ground, sieved and the chemical compositions were determined. Test samples were produced by blending the Gezawa stone with various proportions of Gezawa clay. The refractoriness of the samples was measured, and the samples were then fired to 1100and standard properties such as thermal shock resistance, cold crushing strength and apparent porosity were determined. The result shows that addition of Gezawa clay to Gezawa stone improves its thermal shock resistance but reduces the refractoriness, while the porosity was found to be within the specified range for fire clay and the cold crushing strength of the samples was high. Compromise could be made in selecting the percentage that would suit certain application.

Synthesis of Coal Dust Depressor and its Application in Preventing Coal Dust

2012 ◽  
Vol 482-484 ◽  
pp. 2301-2306 ◽  
Author(s):  
Fang Qin Cheng ◽  
Shu Yan Cheng ◽  
Yan Xia Guo ◽  
Li Qiong Cao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Coal Dust ◽  
Raw Material ◽  
Surface Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stock Pile ◽  
Scanning Electron

A novel coal dust depressor was prepared by alkalization and etherficayion reactions using wastepaper as raw material. The sample was characterized by means of FTIR spectroscopy (FTIR)、scanning electron microscopy (SEM)、X-ray diffraction (XRF) and viscometer measurements. The coal dust inhibitor was developed to suppress flying dust over coal dump and conveyor. The result shows that flying coal dust was prevented by intrinsic viscosity of coal dust depressor which was sprayed on the surface stock pile can make the surface material bond with each other to form layer of crust, having a role of dust prevention. Application of the coal dust depressor can reduce the losses of coal and protect the environment from being polluted.

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