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 Effect of Incremental Utilization of Unground Sea Sand Ore on the Consolidation and Reduction Behavior of Vanadia–Titania Magnetite Pellets

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 269
Author(s):  
Zhenxing Xing ◽  
Gongjin Cheng ◽  
Zixian Gao ◽  
He Yang ◽  
Xiangxin Xue
Keyword(s):  
Compressive Strength ◽  
New Zealand ◽  
Reduction Rate ◽  
Reduction Process ◽  
Production Costs ◽  
Raw Material ◽  
Iron And Steel ◽  
Sea Sand ◽  
Oxidized Pellets ◽  
Magnetite Pellets

In the iron and steel industry, improving the usage amount of New Zealand sea sand ore as a raw material for ironmaking can reduce the production costs of iron and steel enterprises to a certain extent. In this paper, New Zealand sea sand ore without any grinding pretreatment was used as a raw material, oxidized pellets were prepared by using a disc pelletizer, and the effect of sea sand ore on the performance of green pellets and the metallurgical properties of oxidized pellets was investigated. The effects of sea sand ore on the compressive strength, falling strength, compressive strength of oxidized pellets, and reduction performance were mainly investigated. X-Ray Diffraction (XRD) patterns and Scanning Electron Microscope (SEM) analysis methods were used to discuss the influence of sea sand ore on the microstructure of the pellets’ oxidation and reduction process. As the amount of sea sand ore used increased, the compressive strength of green pellets was gradually decreased, and the falling strength of green pellets and the compressive strength of oxidized pellets were gradually increased. When the amount of sea sand ore used was 40%, the reduction swelling index of pellets was 16.31%. The increase of sea sand ore used made the reduction of pellets suppressed and the reduction rate decreased. When the amount of sea sand ore used increased to 40%, the reduction degree of sea sand ore pellets was only 60.06%. The experimental results in this paper provide specific experimental data for the large-scale application of New Zealand sea sand ore in the blast furnace ironmaking process.

Optimization of experimental conditions on preparation of oxidized pellets with New Zealand sea sand ore

2020 ◽  
Vol 117 (4) ◽  
pp. 411
Author(s):  
Zhenxing Xing ◽  
Gongjin Cheng ◽  
Zixian Gao ◽  
He Yang ◽  
Xiangxin Xue
Keyword(s):  
Compressive Strength ◽  
New Zealand ◽  
Raw Material ◽  
Process Conditions ◽  
Experimental Conditions ◽  
Iron And Steel ◽  
Sea Sand ◽  
Oxidized Pellets ◽  
Roasting Temperature ◽  
Roasting Time

In the iron and steel industry, improving the usage amount of New Zealand sea sand ore as a raw material for ironmaking can reduce the production costs of iron and steel enterprises to a certain extent. In this paper, the New Zealand sea sand ore without any grinding pretreatment was used as raw material, oxidized pellets were prepared by using a disc pelletizer, and the experimental conditions for preparing oxidized pellets were investigated and optimized. The effects of binder dosages, roasting temperature and roasting time on the properties of pellets were mainly investigated, and the effects of roasting temperature and roasting time on the microstructure of oxidized pellets was discussed by researching XRD patterns and SEM-EDS. With the increase of binder dosages, the drop strength of green pellets and the compressive strength of oxidized pellets were gradually increased. With the increase of roasting temperature and roasting time, the compressive strength of oxidized pellets increased gradually. When the amount of New Zealand sea sand ore was increased to 40–50%, the optimal process conditions for the preparation of oxidized pellets were as follows: the dosage of binder was 1.5%, the roasting temperature was 1200 °C, and the roasting time was 20 min.

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%.

Preparation of Direct Reduction Sponge Iron (DRI) Using Pyrite Cinder Containing Nonferrous Metals

2017 ◽  
Vol 36 (10) ◽  
pp. 971-978
Author(s):  
Tiejun Chun ◽  
Hongming Long ◽  
Zhanxia Di ◽  
Qingmin Meng ◽  
Ping Wang
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Removal Rate ◽  
Direct Reduction ◽  
Reduction Process ◽  
Nonferrous Metals ◽  
Reduction Roasting ◽  
Pyrite Cinder ◽  
Direct Reduction Iron ◽  
Oxidized Pellets

AbstractPyrite cinder is a solid waste generated by the sulfuric acid industry and is considered environmentally hazardous. It contains abundant iron, such as Fe2O3 and Fe3O4, and nonferrous metals, such as zinc, lead and copper. In order to try and recycle this material as a source of Fe units, preparation of direct reduction iron (DRI) using pyrite cinder was investigated by coal-based grate rotary kiln process. This process includes chloridizing and reduction roasting. The results show that 97 % lead was removed after the chloridizing process. Copper was only detached in chloridizing process with the removal rate of 78.49 %. Furthermore, the removal of zinc was carried out in both chloridizing and reduction process, and the removal rate of 96.76 % was achieved after reduction roasting. The final product representing a metallization degree of 93.36 % with compressive strength of 1,198 N/pellet was obtained after the oxidized pellets were reduced at 1,050 °C for 80 min.

Oxidizing Roasting Performances of Coke Fines Bearing Brazilian Specularite Pellets

2016 ◽  
Vol 35 (6) ◽  
pp. 615-620 ◽  
Author(s):  
Tiejun Chun ◽  
Deqing Zhu
Keyword(s):  
Compressive Strength ◽  
Partial Reduction ◽  
Degradation Index ◽  
Initial Stage ◽  
Oxidized Pellets ◽  
Roasting Process ◽  
Reduction Swelling ◽  
Coke Fines ◽  
New Generation ◽  
Peak Value

AbstractOxidized pellets, consisting of Brazilian specularite fines and coke fines, were prepared by disc pelletizer using bentonite as binder. The roasting process of pellets includes preheating stage and firing stage. The compressive strength of preheated pellets and fired pellets reached the peak value at 1.5% coke fines dosage. During the initial stage of preheating, some original Fe2O3 was reduced to Fe3O4 because of partial reduction atmosphere in pellet. During the later stage of preheating and firing stage, coke fines were burnt out, and the secondary Fe2O3 (new generation Fe2O3) was generated due to the re-oxidization of Fe3O4, which improved the recrystallization of Fe2O3. Compared with the fired pellets without adding coke fines, fired pellets with 1.5% coke fines exhibited the comparable RSI (reduction swelling index) and RDI+3.15 mm (reduction degradation index), and slightly lower RI (reducibility index).

Study on Preparation of Solid Concrete Brick with Recycled Aggregate

2013 ◽  
Vol 648 ◽  
pp. 108-111
Author(s):  
Qi Jin Li ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Mass Fraction ◽  
Recycled Aggregate ◽  
Preparation Process ◽  
Mass Ratio ◽  
Construction Waste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Optimal Value

The construction waste was processed into recycled aggregate to produce solid construction waste brick with grade of MU20. The preparation process of recycled aggregate and the optimal value of mass ratio of water to cement (water cement ratio) and mass ratio of recycled aggregate to cement was studied. The results shows that when the water cement ratio is 0.86 and the mass ratio of recycled aggregate to cement is 5.5 and the dosage of activator is 0.25% (mass fraction with recycled aggregate), the compressive strength of sample is 22.5MPa and can be satisfied with the requirement of MU20 solid concrete brick.

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 The Effect of Fly Ash Microspheres on the Pore Structure of Concrete

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 58 ◽  
Author(s):  
Elzbieta Haustein ◽  
Aleksandra Kuryłowicz-Cudowska
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Total Content ◽  
Spherical Particles ◽  
Hardened Concrete ◽  
Image Analysis System ◽  
Micro Computed Tomography ◽  
Concrete Technology ◽  
Air Voids ◽  
X Ray

The fly ash microspheres (FAMs) formed during the mineral transformation stage in coal combustion are hollow spherical particles with a density less than water. This paper presents the results of X-ray micro-computed tomography and an automatic image analysis system of the porosity in the structure of hardened concrete with microspheres. Concrete mixtures with ordinary Portland cement and two substitution rates of cement by microspheres—5% and 10%—are investigated. For all considered mixes, a constant water/binder ratio (w/b) equal to 0.50 was used. The distribution of the air voids and the compressive strength of the concrete were tested after 28 days. With the increasing mass of cement replacement by FAMs, the compressive strength decreases after 28 days. The total volume of the air voids in hardened concrete with fly ash microspheres tested by X-ray varies from 5.1% to 7.4%. The closed pores constitute more than 80% of the total content of air pores. The study proves that the use of microspheres grains with specific dimensions has a significant impact on concrete porosity. Their application in concrete technology can be an alternative aeration solution for fresh concrete mixes and an effective method for utilization.

Use of Water Glass from Rice Husk and Bagasse Ashes in the Preparation of Fly Ash Based Geopolymer

2019 ◽  
Vol 798 ◽  
pp. 364-369 ◽  
Author(s):  
Khemmakorn Gomonsirisuk ◽  
Parjaree Thavorniti
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Ball Mill ◽  
Water Glass ◽  
Rice Husk Ash ◽  
Raw Materials ◽  
Agricultural Waste ◽  
Preparation Process

The aim of this work is to study the feasibility of preparation of fly ash based geopolymer using sodium water glass from agricultural waste as alternative activators. Rice husk ash and bagasse ash were used as raw materials for producing sodium water glass solution. The sodium water glass were produced by mixing rice husk ash and bagasse ash with NaOH in ball mill and boiling. The prepared sodium water glass were analyzed and used in geopolymer preparation process. The geopolymer paste were prepared by adding the obtained water glass and NaOH with fly ash. After cured at ambient temperature for 7 days, mechanical properties were investigated. Bonding and phases of the geopolymer were also characterized. The geopolymer from rice husk ash presented highest compressive strength about 23 MPa while the greatest for bagasse ash was about 16 MPa.

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