scholarly journals Effect of a calcined alumina additive amount on the properties of zirconia ramming mix on а phosphate bond

2020 ◽  
Vol 120 ◽  
pp. 52-65
Author(s):  
V. V. Martynenko ◽  
P. O. Kushchenko ◽  
V. V. Primachenko ◽  
I. G. Shulik ◽  
E. B. Protsak ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Technology Development ◽  
Cubic Phase ◽  
Phosphate Bond ◽  
Cold Crushing Strength ◽  
New Type ◽  
Shock Resistance ◽  
Scientific Results ◽  
Carbon Black Production

An effect of alumina additive amount on the main properties of ramming mix samples based on zirconia stabilized with calcium oxide on a phosphate bond was studied, as well as the processes of phase formation in these samples. It was found that, the alumina additive introduction activates the ZrO2 cubic phase destabilization, but does not cause softening of the samples structure. This is due to the fact that, as a result of the interaction of alumina with CaO released from the solid solution with ZrO2, elongated prismatic crystals of calcium hexaaluminate are formed, which reinforce and strengthen the samples structure. It was shown that, the samples composition containing 10 % alumina additive is optimal in terms of porosity, strength, and thermal shock resistance: ZrO2 + НfO2 — 83.52 wt. %; CaO — 3.86 wt. %; open porosity-— 15.9 %, cold crushing strength —62 N/mm2, thermal shock resistance (1300 ºС — water) — 6 thermal cycles, change in linear dimensions — 1 %. The obtained scientific results were used in the technology development of a new type of product — a mixture of powders for zirconia-alumina ramming mix, the manufacture of which was mastered at JSC "URIR named after A. S. Berezhnoy". The developed ramming mix is recommended for use, in particular, for making lining at the border of combustion and mixing zones of carbon black production reactors.

The Limitation of Evaluating Thermal Shock Resistance of Al2O3-SiO2 Refractory by Measuring Strength Loss Rate

2011 ◽  
Vol 295-297 ◽  
pp. 2309-2313
Author(s):  
Xin Liu ◽  
Dian Li Qu ◽  
Zhi Jian Li
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Loss Rate ◽  
Strength Loss ◽  
X Ray Diffraction ◽  
Initial State ◽  
X Ray ◽  
Cold Crushing Strength ◽  
Shock Experiment ◽  
Shock Resistance

This paper deeply studied the limitation of evaluating the thermal shock resistance of Al2O3-SiO2 refractory by measuring Strength Loss Rate (SLR). By means of supersonic, X-ray diffraction (XRD), the results were drawn as followed.1)After the thermal shock experiment for mullite based A-S refractory, which were composed by mullite and corundum, the supersonic velocity slowed down as it going through the sample while the cold crushing strength abnormally increased at initial state.2) The strength increased remarkably with the ascending of mullite fraction.3)It is inadequate to evaluate the thermal shock resistance of mullite based A-S refractory by strength loss rate.

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.

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.

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

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.

scholarly journals The effect of carbon and polypropylene fibers on thermal shock resistance of the refractory castable

2017 ◽  
Vol 23 (5) ◽  
pp. 672-678 ◽  
Author(s):  
Valentin ANTONOVIČ ◽  
Jerzy WITEK ◽  
Romualdas MAČIULAITIS ◽  
Renata BORIS ◽  
Rimvydas STONYS
Keyword(s):  
Thermal Cycling ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Mechanical Characteristics ◽  
Positive Impact ◽  
Temperature Treatment ◽  
Polypropylene Fibers ◽  
Channel Formation ◽  
Cold Crushing Strength ◽  
Shock Resistance

This work investigates medium cement refractory castable with additives of carbon and polypropylene fibers. The peculiarities of microstructure changes in the fiber and castable matrix contact zone, channel formation, and changes of cold crushing strength of fiber additives, which have a refractory castable matrix under temperature treatment, were investigated. The investigation results allowed to predict that using a mix of fibers more effective than using them indi­vidually. The influence of fiber additives on the mechanical characteristics and thermal shock resistance of the refractory castable with fiber additives was tested. It was found that the addition of carbon fiber has a positive impact on the ther­mal shock resistance of the investigated castable, which is confirmed by the results obtained by thermal cycling, as well as by the values calculated for thermal shock resistance R4 and Rst. In addition, the results of the investigation of thermal cycling show that the value of the thermal shock resistance was highest when a mixed fiber additive (CF+PP) was used.

scholarly journals Research of kind and quantity of chromic oxide addition influence on alumina-chromia-zirconium silicate refractories properties

2017 ◽  
Vol 117 ◽  
pp. 24-32
Author(s):  
V. V. Martynenko ◽  
V. V. Primachenko ◽  
I. G. Shulyk ◽  
Yu. Ye. Mishnyova ◽  
K. I. Kushchenko ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Open Porosity ◽  
Thermal Shock Resistance ◽  
Chromic Oxide ◽  
Crushing Strength ◽  
Mass Part ◽  
Oxide Addition ◽  
Zirconium Silicate ◽  
Cold Crushing Strength ◽  
Shock Resistance

Research of pigment chromic oxide addition influence on properties of alumina-chromia-zirconium silicate refractories simples with a mass part 30 and 15 % Cr2O3 got by the semidry pressing method is carried out. It is set, that in samples made from batch with 30 % Cr2O3 optimal quantity of pigment chromic oxide, which provide achieving close properties indexes compared to indexes of samples without this component should be considered 10 %, and in samples made from batch with 15 % Cr2O3 — 6 %. The properties indexes of samples with 30 % Cr2O3 containing 10 % pigment chromic oxide are: mass part of Al2O3 — 62.7 %, Cr2O3 — 30.3 %, ZrO2 — 5.8 %, open porosity 22.6 %, apparent density 3.27 g/cm3, cold crushing strength 123 N/mm2, thermal shock resistance on the mode 950 оC — water 4 thermal cycles, residual changes of sizes at a temperature 1650 оC, exposition 2 hours 0 %. The properties indexes of samples with 15 % Cr2O3 containing 6 % pigment chromic oxide are: mass part of Al2O3 — 76.4 %, Cr2O3 — 15.2 %, ZrO2 — 6.1 %, open porosity 22.4 %, apparent density 3.17 g/cm3, cold crushing strength 145 N/mm2, thermal shock resistance on the mode 950 оC — water 4 thermal cycles, residual changes of sizes at a temperature 1650 оC, exposition 2 hours 0 %. Obtained results are used at making of products for glass melting furnace of industrial lining for fiberglass production from E glass.

scholarly journals INVESTIGATIONS OF LOW-CEMENT CASTABLES WITH SHAMOTTE AGGREGATE/MAŽACEMENČIO KAITRAI ATSPARAUS BETONO SU ŠAMOTO UŽPILDU TYRIMAI

1999 ◽  
Vol 5 (1) ◽  
pp. 32-35
Author(s):  
Stasys Goberis ◽  
Liutauras Merlinskaja ◽  
Ina Pundienė
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
High Water ◽  
Furnace Lining ◽  
High Water Absorption ◽  
Cold Crushing Strength ◽  
Normal Quantity ◽  
Shock Resistance

The castables with low-cement and normal quantity cement in its composition physical and mechanical properties was investigated. Aggregates of recycled shamotte waste, which are characterised by high water absorption, were used for castables. The results of influence of firing temperature on density and cold crushing strength for three series castables were determined (Fig 1 and 2). Thermal shock resistance, bending strength and deformations of the castables were investigated additionally (Table 2 and Fig 4). The results of investigations showed the advantage of low-cement castables: better thermal shock resistance, higher cold crushing and bending strength after firing at high temperature. The properties of developed low-cement and traditional castables produced with schamotte waste aggregates were compared with the data from German, Danish and Polish castables, a special quality shamotte aggregate was used (Table 1). Low-cement castable based on shamotte waste aggregates were developed and used for producing “Ipsen” furnace lining items.

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