Preparation of CaO-containing carbon pellets from coking coal and calcium oxide: Effects of temperature, pore distribution and carbon structure on compressive strength in pyrolysis furnace

2021 ◽  
Vol 28 (7) ◽  
pp. 1153-1163
Author(s):  
Xiao-min You ◽  
Xue-feng She ◽  
Jing-song Wang ◽  
Qing-guo Xue ◽  
Ze-yi Jiang
Keyword(s):  
Compressive Strength ◽  
Calcium Oxide ◽  
Pore Distribution ◽  
Carbon Structure ◽  
Coking Coal ◽  
Pyrolysis Furnace ◽  
Effects Of Temperature ◽  
Carbon Pellets

scholarly journals Low-temperature degradation resistance and plastic deformation of ATZ ceramics stabilized by CaO

2021 ◽  
Vol 2103 (1) ◽  
pp. 012075
Author(s):  
AA Dmitrievskiy ◽  
DG Zhigacheva ◽  
VM Vasyukov ◽  
PN Ovchinnikov
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Plastic Deformation ◽  
Compressive Strength ◽  
Phase Composition ◽  
Low Temperature ◽  
Uniaxial Compression ◽  
Calcium Oxide ◽  
Tetragonal Phase ◽  
Room Temperature

Abstract In this work, the phase composition (relative fractions of monoclinic m-ZrO2, tetragonal t-ZrO2, and cubic c-ZrO2 phases) and mechanical properties (hardness, fracture toughness, compressive strength) of alumina toughened zirconia (ATZ) ceramics, with an addition of silica were investigated. Calcium oxide was used as a stabilizer for the zirconia tetragonal phase. It was shown that CaO-ATZ+SiO2 ceramics demonstrate increased resistance to low-temperature degradation. The plasticity signs at room temperature were found due to the SiO2 addition to CaO-ATZ ceramics. A yield plateau appears in the uniaxial compression diagram at 5 mol. % SiO2 concentration. It is hypothesized that discovered plasticity is due to the increased t→m transformability.

scholarly journals A Simple Method of Evaluating the Thermal Properties of Metallurgical Cokes under High Temperature

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5767
Author(s):  
Guangzhi Yang ◽  
Xiaoqiang Wang ◽  
Ting Shi ◽  
Xinci Wu ◽  
Yuhua Xue
Keyword(s):  
High Temperature ◽  
Reactivity Index ◽  
Gas Composition ◽  
Carbon Structure ◽  
Simple Method ◽  
Hot Strength ◽  
Optical Texture ◽  
Testing Method ◽  
Effects Of Temperature ◽  
Temperature Time

The reactivity index of weight loss (RI) and tumbling strength after the reaction (I10600) of manufacturing coke were first tested at a temperature series of 1100, 1200, and 1300 °C under CO2 atmosphere with different compositions and duration times to study the effects of temperature, time, and gas composition on coke hot strength. Then the RI/I10600, carbon structure, and optical texture of the cokes prepared from different single coals were mainly studied after a solution reaction with CO2 under a high temperature of 1300 °C and a standard temperature of 1100 °C. It was found that temperature greatly affects the RI/I10600 of coke, especially at high temperatures up to 1300 °C. Compared with standard tests under 1100 °C, the changes of RI/I10600 for different cokes are very different at 1300 °C, and the changes are greatly related to coke optical texture. Under a high temperature in the testing method, the tumbling strength of cokes with more isotropy increased, whereas it decreased for those with less isotropy. This simple method of using high temperature could yield the same results when compared with complicated simulated blast furnace conditions.

scholarly journals Gene-Expression Programming-Based Model for Estimating the Compressive Strength of Cement-Fly Ash Stabilized Soil and Parametric Study

2021 ◽  
Vol 6 (12) ◽  
pp. 181
Author(s):  
Van-Ngoc Pham ◽  
Erwin Oh ◽  
Dominic E. L. Ong
Keyword(s):  
Gene Expression ◽  
Compressive Strength ◽  
Fly Ash ◽  
Calcium Oxide ◽  
Parametric Study ◽  
Soil Stabilization ◽  
Gene Expression Programming ◽  
Superior Performance ◽  
Stabilized Soil ◽  
Research Findings

The study aims to develop a reliable model using gene-expression programming (GEP) technique for estimating the unconfined compressive strength (UCS) of soil stabilization by cement and fly ash. The model considered the effects of several parameters, including the fly ash characteristics such as calcium oxide (CaO) content, CaO/SiO2 ratio, and loss of ignition. The research results show that the proposed model demonstrates superior performance with a high correlation coefficient (R > 0.955) and low errors. Therefore, the model could be confidently applied in practice for a variety of fly ash qualities. Besides, the parametric study was conducted to examine the effect of fly ash characteristics on the strength of soil stabilization. The study indicates that if the fly ash contains a high amount of calcium oxide, the strength of fly ash stabilized soil is significant. In addition, fly ash could be used in combination with cement to increase the strength of the mixture. A fly ash replacement ratio is suggested from 0.19 to 0.35, corresponding to the total binder used from 10% to 30%. The research findings could help engineers in optimizing the fly ash proportion and estimating the UCS of soil stabilization by cement and fly ash.

Application of Immobilized Nitrifiers Gel to Removal of High Ammonium Nitrogen

1994 ◽  
Vol 29 (9) ◽  
pp. 241-250 ◽  
Author(s):  
Kazuhiro Tanaka ◽  
Masakazu Nakao ◽  
Naomichi Mori ◽  
Hiroyoshi Emori ◽  
Tatsuo Sumino ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Activated Sludge ◽  
Arrhenius Equation ◽  
Ammonium Nitrogen ◽  
Full Scale ◽  
Exhaust Gas ◽  
Municipal Sludge ◽  
Effects Of Temperature ◽  
Sludge Drying ◽  
Pilot Plant Study

Immobilized nitrifiers gel was used to remove high levels of ammonium nitrogen from the exhaust gas scrubber wastewater of a municipal sludge drying facility. Prior to full-scale application, the effects of temperature and pH on characteristics of immobilized gel pellets and the removal of ammonium nitrogen were investigated. The activated sludge was entrapped in polyethylene glycol gel, and elastic pellets containing activated sludge were obtained. The lifespan of the pellets in terms of compressive strength was estimated using Arrhenius equation. The results indicated that the lifespan of the pellets was at least five years at pH between 6 and 9, and at a temperature of 40 °C. The pilot plant study showed that wastewater containing 95-260 mg/l of ammonium nitrogen could be treated by immobilized pellets within a retention time of 6 hours and the removal of ammonium nitrogen was 98%. The 480 m3/d full-scale plant was constructed and has been operated successfully.

Hydration Properties of Steel Slag under Different Curing Temperatures

2014 ◽  
Vol 507 ◽  
pp. 295-299 ◽  
Author(s):  
Bo Zhang ◽  
Jin Hu ◽  
Meng Yuan Li
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Water Content ◽  
Cement Paste ◽  
Steel Slag ◽  
Pore Distribution ◽  
Curing Temperature ◽  
Hydration Properties ◽  
Evaporable Water ◽  
Temperature Conditions

The non-evaporable water content, compressive strength, and pore distribution of steel slag paste cured under different curing temperature conditions were investigated in this paper. The non-evaporable water content of steel slag paste at early ages is obviously larger at higher curing temperature. At the age of 28 days, the non-evaporable water content of steel slag paste at normal curing temperature is close to that at high curing temperature, but the compressive strength of steel slag paste at normal curing temperature is much lower than that at high curing temperature. The pore structure of steel slag paste is much coarser than that of cement paste under the same conditions.

scholarly journals Evaluation of the superplasticizer effect on the workability and strength of concrete

2020 ◽  
Vol 9 (1) ◽  
pp. 198
Author(s):  
Salahaldein Alsadey ◽  
Saieed Mohamed
Keyword(s):  
Compressive Strength ◽  
Adverse Effects ◽  
Water Demand ◽  
Fresh Concrete ◽  
Setting Time ◽  
Cement Ratio ◽  
Optimum Dosage ◽  
Effects Of Temperature ◽  
Hot Weather ◽  
Sive Strength

The adverse effects of temperature on the properties of fresh concrete include increased water demand, shorter setting time and increased slump loss. Superplasticizer (SP) is important for enhancing the workability and setting time of concrete in hot weather. Hence, an experi-mental investigation was conducted to determine the optimum dosage of an admixture and to study the effect of over dosing this admixture. Concrete mixes with SP dosages of 0.8%, 1% and 1.2% by weight of cement were prepared along with a control mix (water/cement ratio of 0.55). After casting, the concrete samples underwent normal curing. Among the properties of fresh concrete determined were compressive strength as well as workability. The over dosage of SP appeared to degrade the properties of concrete with an indication of lower compres-sive strength. However, if the dosage levels are lower than the optimum dosage, raising the admixture dosage might help enhance the con-crete characteristics. 

Behavior of Reinforced Concrete Subjected to High Temperatures-A Review

2013 ◽  
Vol 4 (4) ◽  
pp. 281-295 ◽  
Author(s):  
Aijaz Zende ◽  
A. Kulkarni ◽  
Aslam Hutagi
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Concrete Surface ◽  
Concrete Cover ◽  
Mechanical And Thermal Properties ◽  
Reinforcing Bars ◽  
Cover Layer ◽  
Higher Temperature ◽  
Effects Of Temperature

This paper reviews the research carried on effects of fire on the mechanical and thermal properties on concrete. Fire in the structure causes higher temperature at the concrete surface, which causes a reduction in compressive strength, modulus of elasticity of concrete. Though concrete is a poorer conductor than steel, sustained high temperature at the surface leads to progressive heating of the inner layers of concrete. This leads to exposing reinforcing bars to higher temperature; which causes a reduction in the yield stress, ductility and tensile strength of steel. This paper also focuses on the concrete cover, the reinforcement bars in a concrete structure are protected against fire only by the concrete cover layer thus higher is the cover more is the resistance and vice a versa. Effects of temperature on the thermal conductivity of concrete is also discussed in detail.

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