scholarly journals Influence of SiO2 on the Compressive Strength and Reduction-Melting of Pellets

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 852 ◽  
Author(s):  
He Guo ◽  
Xin Jiang ◽  
Fengman Shen ◽  
Haiyan Zheng ◽  
Qiangjian Gao ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Reduction Process ◽  
Melting Behavior ◽  
Sio2 Content ◽  
Reduction Degree ◽  
Negative Effects ◽  
Experimental Conditions ◽  
Compact Structure ◽  
Reduction Behavior ◽  
Effective Utilization

The effects of SiO2 content on the compressive strength, reduction behavior and melting-dripping properties of the pellets were investigated under experimental conditions. The experimental results indicated that the compressive strength of pellets gradually decreased with increasing SiO2 content, mainly because the pellets with high SiO2 had poor crystallization capacity, a more liquid phase and more pores. With increasing SiO2 content from 2.19 wt% to 8.13 wt%, the reduction degree of pellets descreased due to the generation of 2FeO·SiO2. Based on the morphology analysis, inside of the pellets, 2FeO·SiO2 caused the compact structure and fewer microspores with increasing SiO2 content, which was unfavorable for the reduction process and resulted in the decrease of the reduction degree. Also, increasing the SiO2 content had negative effects on the melting-dripping properties of pellets. The melting-dripping properties can be improved by adding some sinter with high basicity in the mixed burden. The current work established the relation between SiO2 content and reduction-melting behavior of pellets, which can provide theoretical and technical support for the effective utilization of pellets with different SiO2 content in blast furnace process.

Effect of BaSO4 on the compressive strength and reduction behavior of pellets

2020 ◽  
Vol 117 (2) ◽  
pp. 207
Author(s):  
Jiantao Ju ◽  
Chenmei Tang ◽  
Xiangdong Xing ◽  
Shan Ren ◽  
Guangheng Ji
Keyword(s):  
Compressive Strength ◽  
Theoretical Basis ◽  
Energy Dispersive Spectrometer ◽  
Reduction Process ◽  
Reduction Degree ◽  
Experimental Conditions ◽  
Reduction Behavior ◽  
Influence Mechanism ◽  
Scanning Electron ◽  
Peak Value

To provide theoretical basis for the production of pellets, the effect of BaSO4 in the range of 0 to 5.0% on properties of pellets was studied under experimental conditions. The influence mechanism of BaSO4 on the compressive strength of preheated pellets as well as roasted pellets and reduction behavior of roasted pellets was investigated by means of scanning electron microscopy-energy dispersive spectrometer (SEM-EDS). From the results, it can be observed that the compressive strength of preheated pellets varies slightly whereas roasted pellets has a great change when BaSO4 content increases from 0 to 5%. The compressive strength of roasted pellets initially increases then decreases, which reaches the peak value of 3411 N with BaSO4 content of 1.5%. The reduction degree enhances from 80.7 to 97.9% and FeO content reduces from 2.33 to 1.57% with increasing BaSO4 content from 0 to 5.0%. The degree of polycrystalline of hematite improves and the hole size increases obviously when BaSO4 content varies from 0 to 1.5%. The crystallization of hematite decreases and the holes whose distribution is uneven increases when BaSO4 content is more than 1.5%. In reduction process, the wustite reduces and metallic iron increases with increasing BaSO4 content from 0 to 5.0%.

scholarly journals Effects of High Proportion Unground Sea Sand Ore on the Preparation Process and Reduction Performance of Oxidized Pellets

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 87 ◽  
Author(s):  
Gong-jin Cheng ◽  
Zhen-xing Xing ◽  
He Yang ◽  
Xiang-xin Xue
Keyword(s):  
Compressive Strength ◽  
New Zealand ◽  
Reduction Process ◽  
Spherical Particles ◽  
Detection Methods ◽  
Preparation Process ◽  
Reduction Degree ◽  
Sea Sand ◽  
Oxidized Pellets ◽  
Reduction Swelling

The New Zealand sea sand ore is a kind of vanadia–titania magnetite formed by erosion in the coastal zone. Because of its coarse particle size, smooth spherical particles, complex chemical composition, it has been added to sinter as an auxiliary material. Based on the principle of optimizing ore blending to strengthen advantages and weaken disadvantages, this paper used New Zealand sea sand raw ore that has not undergone any pretreatment as the main material and prepared it into oxidized pellets using a disc pelletizer and explored the influence of high-proportion unground sea sand ore on the preparation process and reduction performance of oxidized pellets. The influence of unground sea sand ore on the falling strength, compressive strength, reduction swelling index, and reduction degree of pellets was analyzed by the ICPAES, XRF, XRD, SEM-EDS, and other detection methods, and the change laws and influencing factors of oxidized pellets were analyzed. With the increase of the amount of unground sea sand ore used, the falling strength and compressive strength of the green pellets first decreased and then gradually increased, while the compressive strength of the oxidized pellets first increased and then decreased. At the same time, as the amount of sea sand ore used increased, the reduction process of pellets was restricted. The reduction swelling index and the reduction degree index generally show a downward trend. However, the compressive strength of the pellets gradually increased after reduction. Through the research on the pellet-forming performance and reduction properties of unground sea sand ore, it is shown that when the amount of unground sea sand ore used was 40%, it can still be used as raw material for blast furnace ironmaking. Thus, this research provided specific data support for iron and steel enterprises to improve the ratio of unground sea sand ore and reduce production cost.

scholarly journals Evaluation of Indigenous Olive Biocontrol Rhizobacteria as Protectants against Drought and Salt Stress

2021 ◽  
Vol 9 (6) ◽  
pp. 1209
Author(s):  
Nuria Montes-Osuna ◽  
Carmen Gómez-Lama Cabanás ◽  
Antonio Valverde-Corredor ◽  
Garikoitz Legarda ◽  
Pilar Prieto ◽  
...  
Keyword(s):  
Salt Stress ◽  
Abiotic Stresses ◽  
Biochemical Parameters ◽  
Biocontrol Agent ◽  
Negative Effects ◽  
Experimental Conditions ◽  
Acds Gene ◽  
Drought And Salt Stress ◽  
Physiological And Biochemical

Stress caused by drought and salinity may compromise growth and productivity of olive (Olea europaea L.) tree crops. Several studies have reported the use of beneficial rhizobacteria to alleviate symptoms produced by these stresses, which is attributed in some cases to the activity of 1-aminocyclopropane-1-carboxylic acid deaminase (ACD). A collection of beneficial olive rhizobacteria was in vitro screened for ACD activity. Pseudomonas sp. PICF6 displayed this phenotype and sequencing of its genome confirmed the presence of an acdS gene. In contrast, the well-known root endophyte and biocontrol agent Pseudomonas simiae PICF7 was defective in ACD activity, even though the presence of an ACD-coding gene was earlier predicted in its genome. In this study, an unidentified deaminase was confirmed instead. Greenhouse experiments with olive ‘Picual’ plants inoculated either with PICF6 or PICF7, or co-inoculated with both strains, and subjected to drought or salt stress were carried out. Several physiological and biochemical parameters increased in stressed plants (i.e., stomatal conductance and flavonoids content), regardless of whether or not they were previously bacterized. Results showed that neither PICF6 (ACD positive) nor PICF7 (ACD negative) lessened the negative effects caused by the abiotic stresses tested, at least under our experimental conditions.

Reduction Kinetics of Mill Scale Briquettes by Using A3 Fine Coal as a Reductant

2021 ◽  
Vol 21 (4) ◽  
pp. 2563-2567
Author(s):  
Nguyen Hoang Viet ◽  
Pham Ngoc Dieu Quynh ◽  
Nguyen Thi Hoang Oanh
Keyword(s):  
Reaction Rate ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Reaction Rate Constant ◽  
Reduction Degree ◽  
Furnace Temperature ◽  
Time Duration ◽  
Mill Scale ◽  
Fine Coal ◽  
Kinetics Of

In this work, a mixture of mill scale with 5 wt% molasses as binder was pressed under pressure of 200 MPa to prepare briquettes. The reduction process was performed at the temperature of 1000, 1050, 1100, 1150 and 1200 °C in the bed of A3 fine coal as the reductant. The degree of reduction was evaluated at time duration of 15, 30, 45, 60, 90 and 150 minutes, after the furnace temperature reached the predetermined reduction temperature. The highest reduction degree is 94.7% at the reduction process temperature of 1200 °C. Reaction rate constant (k) increased from 4.63×10-4 to 5.03×10-3 min-1 when the temperature increased from 1000 to 1200 °C. The apparent activation energy of the reduction reaction (Ea) is about 95.6 kJ/mole.

scholarly journals Hydration study of mechanically activated mixtures of Portland cement and fly ash

2007 ◽  
Vol 72 (6) ◽  
pp. 591-604 ◽  
Author(s):  
Gordana Stefanovic ◽  
Ljubica Cojbasic ◽  
Zivko Sekulic ◽  
Srdjan Matijasevic
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Mechanical Activation ◽  
Early Period ◽  
Negative Effects ◽  
Early Hydration ◽  
Cement Pastes ◽  
Dta And Tg ◽  
Low Activity

Fly ash (FA) can be used in cement mixtures with certain limitations. The problem of the mentioned mixtures lies in the insufficient activity of the particles of FA in the reactions which are important for the establishment of the mechanical characteristics of cement. This is particularly true for the hydration reactions. As a result of this, cement pastes formed by mixing ash and clinker have worse characteristics compared to those of pure Portland cement (PC), especially in the early period of setting. As is well known, FA can be a good solution for the neutralization of the negative effects generated due to the creation of free Ca(OH)2 during the hydration of PC, provided that the problems with the low activity of FAare overcome. For the experiments in this study, a mixture of Portland cement and fly ash was used, the content of ash in the mixture being 30 % and 50 %. Mechanical activation was performed in a vibrating ring mill. The goal of this study was to demonstrate, through experimental results, that during the mechanical activation of a PC and FA mixture, the components in the mixture which mostly affect the direction, rate and range of hydration reactions occurring in the mixture had been activated. The values of the compressive strength of the activated and non-activated mixtures and the changes of their specific surface area proved that during the grinding process, the mixture PC+FA had been mechanically activated. The highest increase of compressive strength was achieved in the early period of setting, which indicates an improvement in the early hydration of the mixture. XRD, DTA and TG analyses showed that the alite (C3S) and belite (C2S) from the PC and a part of the fly ash were activated. .

scholarly journals Religion, Moral and Modernisation of Urban Society: A Study on the Roles of Religion in Youth Development in Lampung, Republic of Indonesia

2020 ◽  
Vol 2 (2) ◽  
pp. 109-116
Author(s):  
Suhandi ◽  
Azhar Jaafar
Keyword(s):  
Youth Development ◽  
Rural Areas ◽  
Reduction Process ◽  
Negative Effects ◽  
Process Data ◽  
The People ◽  
Negative Impacts ◽  
Multi Access ◽  
Almost All ◽  
Role Of Religion

Modernisation is the consequence of the demands of the development that brings negative impacts to the society. It is undeniable that modernization also brings abundance of positive impacts that ease the life of people and that modernization and humanization cannot be separated. In this context, the youth are considered as unstable being, who easily being controlled by multi-access communication technology; from social, fashion, behaviour, lifestyle, and ideology. Almost all of the damaging sides of technology affect the youth. Religion as the spiritual agent has a major role in combating this change in the society. Religion can act as the social control to hinder from immoral behaviour and worthless actions among the society. The main issue in the current study is to investigate the role of religion in strengthening the moral among the teenagers. This research was conducted by using qualitative method. Data were collected through observation, interview and documentation. The participants of this research were the people of the rural areas in Bandar Lampung. After data collection was carried out, the data were processed qualitatively using the data reduction process, data exposure, and data verification. To conclude, the existence of the negative effects of modernization resulted from lack of religious virtues and parents’ control over their children’s social behaviour.

Evaluation of characteristics of fly ash-reinforced clay bricks as building material

2016 ◽  
Vol 40 (6) ◽  
pp. 530-543 ◽  
Author(s):  
Harjinder Singh ◽  
GS Brar ◽  
GS Mudahar
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Test Results ◽  
Excellent Performance ◽  
Additional Advantage ◽  
Effective Utilization ◽  
Clay Bricks ◽  
Filling Ability ◽  
Combined Use ◽  
Reinforced Clay

The main purpose of this study is to evaluate the technical possibilities of incorporating fly ash in clay bricks to produce an industry-acceptable bricks. The effect of fly ash with high replacing ratio from (0% to 50%) of clay on properties of bricks was analyzed. The tests of bulk density, porosity, water absorption, compressive strength, and flexural strength were conducted in accordance with relevant Indian standards in order to estimate the effect of the fly ash content on the performance of the hardened bricks. Novel lightweight bricks have been produced by sintering mixes of fly ash and clay. The results show that fly ash addition up to 50% (in weight) can be beneficial for properties of sintered bricks at temperature 1000°C. Test results revealed that the combined use of clay and fly ash exhibited excellent performance due to efficient micro-filling ability and pozzolanic activity. These bricks give better compressive strength with additional advantage of being lightweight and more environmentally friendly. Effective utilization of fly ash additive is not only for conservation of natural clay resources but also an alternative solution to difficult and expensive waste disposal problems.

Catalytic Reduction Performance of Carboxylated Alginic Acid Derivatives

2021 ◽  
Author(s):  
Raed H. Althomali ◽  
Khalid A. Alamry ◽  
Mahmoud Hussein Abdo ◽  
Shams H. Abdel-Hafez
Keyword(s):  
Metal Complexes ◽  
Metal Ion ◽  
Alginic Acid ◽  
Catalytic Reduction ◽  
Organic Dyes ◽  
Reduction Process ◽  
Spectroscopic Techniques ◽  
Reduction Behavior ◽  
Long Time ◽  
Ft Ir

Abstract In this study, the catalytic reduction behavior of carboxylated alginic acid derivatives has been investigated against the harmful organic dyes including Methyl Orange (MO) and Congo Red (CR). Alginic acid was firstly oxidized through an easy addition of KMnO4 as an oxidizing agent. A carboxylated alginic acid (CAA) has been interacted with selected metal ions (Sn, Fe, Ni, and Zr) through coordination bonds at the value of pH = 4 to form the corresponding metal complexes namely: Sn-CAA, Fe-CAA, Ni-CAA and Zr-CAA. The consistency of the coordination was confirmed by several spectroscopic techniques including FT-IR, XRD, SEM, and EDX. The catalytic reduction of these metal ion-based products was carried out against MO and CR in the presence of NaBH4 as a reducing agent under UV irradiation. All catalysts based metal complexes showed enhanced catalytic reduction against CR compared to MO. Among all those mentioned metal complexes Sn-CAA showed the best catalytic reduction of these dyes. The time taken by the Sn-CAA for CR, and MO is 5 and 7min respectively. Ni-CAA was classified as the second efficient product against both dyes, where the reduction process took 20 and 9 min respectively. The other two catalysts took a long time for CR and MO reduction. Zr-CAA showed more than 80 % reduction of only CR dye within 20 min. Whereas, Fe-CAA did not show any significant sign of reduction against both the dyes after the same time. The order of higher catalytic reduction was illustrated as: Sn-CAA > Ni-CAA > Zr-CAA = Fe-CAA.

scholarly journals Industrial Waste Utilization of Carbon Dust in Sustainable Cementitious Composites Production

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3295
Author(s):  
Mohammad R. Irshidat ◽  
Nasser Al-Nuaimi
Keyword(s):  
Compressive Strength ◽  
Industrial Waste ◽  
Cement Mortar ◽  
Waste Utilization ◽  
Cementitious Composites ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Compact Structure ◽  
X Ray ◽  
Industrial Waste Utilization

This paper experimentally investigates the effect of utilization of carbon dust generated as an industrial waste from aluminum factories in cementitious composites production. Carbon dust is collected, characterized, and then used to partially replace cement particles in cement mortar production. The effect of adding different dosages of carbon dust in the range of 5% to 40% by weight of cement on compressive strength, microstructure, and chemical composition of cement mortar is investigated. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF) analysis are used to justify the results. Experimental results show that incorporation of carbon dust in cement mortar production not only reduces its environmental side effects but also enhances the strength of cementitious composites. Up to 10% carbon dust by weight of cement can be added to the mixture without adversely affecting the strength of the mortar. Any further addition of carbon dust would decrease the strength. Best enhancement in compressive strength (27%) is achieved in the case of using 5% replacement ratio. SEM images show that incorporation of small amount of carbon dust (less than 10%) lead to produce denser and more compact-structure cement mortar.

Sign in / Sign up

Export Citation Format

Share Document