Composite zircon ceramics based on raw materials activated by ammonium bifluoride

2021 ◽  
pp. 44-50
Author(s):  
Sh. M. Sharafeev ◽  
V. I. Vereshchagin
Keyword(s):  
Sintering Temperature ◽  
Raw Materials ◽  
Excessive Amount ◽  
Ammonium Bifluoride ◽  
Natural Zircon ◽  
Dissociated Zircon ◽  
High Degree

The results of studies of the synthesis processes of baddeleyite-zircon ceramics based on fluorinated plasmadissociated and natural zircon are presented. It was found that to obtain densely sintered ceramics based on fluorinated natural zircon, the introduction of CaO is required to stabilize free ZrO2 in the composition of the ceramics. The introduction of Y2O3 into the composition of ceramics based on plasma-dissociated zircon makes it possible to reduce the sintering temperature from 1600 to 1500 °C. It is difficult to obtain ceramics based on plasmadissociated zircon with a high degree of fluorination due to the formation of an excessive amount of ZrF4.

A possibility of using nickel concentrate, obtained as a result of hydrometallurgical enrichment of manganese-containing raw materials, at steel alloying

2020 ◽  
Vol 76 (7) ◽  
pp. 709-715
Author(s):  
O. Yu. Kichigina
Keyword(s):  
Raw Materials ◽  
Experimental Studies ◽  
Selective Extraction ◽  
Technological Parameters ◽  
Nickel Iron ◽  
Nickel Recovery ◽  
Nickel Concentrate ◽  
Steel Alloying ◽  
High Degree ◽  
Comprehensive Processing

At production of stainless steel expensive alloying elements, containing nickel, are used. To decrease the steel cost, substitution of nickel during steel alloying process by its oxides is an actual task. Results of analysis of thermodynamic and experimental studies of nickel reducing from its oxide presented, as well as methods of nickel oxide obtaining at manganese bearing complex raw materials enrichment and practice of its application during steel alloying. Technology of comprehensive processing of complex manganese-containing raw materials considered, including leaching and selective extraction out of the solution valuable components: manganese, nickel, iron, cobalt and copper. Based on theoretical and experiment studies, a possibility of substitution of metal nickel by concentrates, obtained as a result of hydrometallurgical enrichment, was confirmed. Optimal technological parameters, ensuring high degree of nickel recovery out of the initial raw materials were determined. It was established, that for direct steel alloying it is reasonable to add into the charge pellets, consisting of nickel concentrate and coke fines, that enables to reach the through nickel recovery at a level of 90%. The proposed method of alloying steel by nickel gives a possibility to decrease considerably steel cost at the expense of application of nickel concentrate, obtained out of tails of hydrometallurgical enrichment of manganese-bearing raw materials, which is much cheaper comparing with the metal nickel.

scholarly journals Pressureless Sintering of YIG Ceramics from Coprecipitated Nanopowders

2021 ◽  
Vol 7 (5) ◽  
pp. 56
Author(s):  
Yimin Yang ◽  
Xiaoying Li ◽  
Ziyu Liu ◽  
Dianjun Hu ◽  
Xin Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Calcination Temperature ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Secondary Phase ◽  
Coprecipitation Method ◽  
Pressureless Sintering ◽  
Densification Behavior ◽  
Sintering Process

Nanoparticles prepared by the coprecipitation method were used as raw materials to fabricate Y3Fe5O12 (YIG) ceramics by air pressureless sintering. The synthesized YIG precursor was calcinated at 900–1100 °C for 4 h in air. The influences of the calcination temperature on the phase and morphology of the nanopowders were investigated in detail. The powders calcined at 1000–1100 °C retained the pure YIG phase. YIG ceramics were fabricated by sintering at 1200–1400 °C for 10 h, and its densification behavior was studied. YIG ceramics prepared by air sintering at 1250 °C from powders calcinated at 1000 °C have the highest in-line transmittance in the range of 1000-3000 nm. When the sintering temperature exceeds 1300 °C, the secondary phase appears in the YIG ceramics, which may be due to the loss of oxygen during the high-temperature sintering process, resulting in the conversion of Fe3+ into Fe2+.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

Preparation and Electrical Property of Calcia Stabilized Zirconia Ceramics

2014 ◽  
Vol 616 ◽  
pp. 157-165 ◽  
Author(s):  
Chang Lian Chen ◽  
Hong Quan Wang ◽  
Jia You Ji ◽  
Ma Ya Luo ◽  
Bo Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Property ◽  
Arrhenius Equation ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Cubic Phase ◽  
Pressureless Sintering ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Sintering Method

In this paper, using ZrO2 and Ca (NO3)•4H2O as raw materials, we prepared a series of calica stabilized zirconia (CSZ) ceramics by pressureless sintering method. The results show that the relative densities of all sintered samples are above 90%, and the sintered samples are composed of cubic, tetragonal and monoclinic ZrO2, and the main phase is cubic ZrO2 and tetragonal ZrO2. The content of cubic phase increases with the increase of sintering temperature and adding CaO content. The grain size of the sintered samples is relatively uniform and some pores exist. Increasing the additive amount of CaO, the conductivity first rises and then decreases, and the conductivity value of the sample containing 5wt% CaO is the maximum. When the sintering temperature is up to 1600 oC, the conductivity of the sample containing 5wt% CaO is up to 0.016S•cm-1 at 800 oC. Furthermore, the conductivity of sintered samples is increasing with the increase of test temperature according to the Arrhenius equation.

Use of Sugarcane Bagasse Ashes as Raw Material in the Replacement of Fluxes for Applications on Porcelain Tile

2016 ◽  
Vol 881 ◽  
pp. 383-386 ◽  
Author(s):  
Raimundo J.S. Paranhos ◽  
Wilson Acchar ◽  
Vamberto Monteiro Silva
Keyword(s):  
Mechanical Properties ◽  
Environmental Impact ◽  
Physical Properties ◽  
Sugarcane Bagasse ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Raw Material ◽  
The Cost ◽  
Potential Use ◽  
Porcelain Tile

This study evaluated the potential use of Sugarcane Bagasse Ashes (SBA) as a flux, replacing phyllite for the production of enamelled porcelain tile. The raw materials of the standard mass components and the SBA residue were characterized by testing by XRF, XRD, AG, DTA and TGA. Test samples were fabricated, assembled in lots of 3 units and sintered at temperatures of 1150 ° C to 1210 ° C. The results of the physical properties, mechanical properties and SEM of the sintered samples, showed that the formulation, G4 - in which applied 10% of SBA replacing phyllite, sintering temperature 1210 ° C showed better performance as the previously mentioned properties due to the formation of mullite crystals, meeting the prerequisites of standards for enamelled porcelain tile, while reducing the environmental impact and the cost of production.

Microstructure, Mechanical Properties, and Electrical Resistivities of Mica Glass-Ceramics with Flake Phlogopite and Waste Glass

2014 ◽  
Vol 602-603 ◽  
pp. 640-643
Author(s):  
Yu Fei Chen ◽  
Yan Gai Liu ◽  
Xiao Wen Wu ◽  
Zhao Hui Huang ◽  
Ming Hao Fang
Keyword(s):  
High Speed ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Waste Glass ◽  
Raw Material ◽  
Bending Test ◽  
Electric Locomotive ◽  
Molding Process ◽  
Electrical Resistivities

Mica glass-ceramics can be applied in all kinds of electrical equipment, locomotive internal circuits in high-speed rail, ordinary electric locomotive and subway locomotive. In this study, mica glass-ceramics were prepared by sintering process using flake mica and waste glass as the main raw material with low cost. Different mica glass-ceramic samples were fabricated by changing the formula of raw materials, molding process and sintering temperature. X-ray diffraction, scanning electron microscopy, three-point bending test, and balanced-bridge technique were applied to investigate the phase, microstructure, mechanical and electrical resistivities of the samples, respectively. The results show that the optimum sintering temperature is 900 to 1000 °C holding for two hours, the desirable ratio is 70 wt% of mica powder while 30 wt% of glass powder. In that condition the sample could be less porosity, high flexural strength (63.3 MPa) and eligible electrical resistivity (0.4×1013 Ω·cm).

scholarly journals INVESTIGATION OF DECOMPOSITION OF PHOSPHATE RAW MATERIALS IN THE PRESENCE OF PEAT USING PHOSPHORIC ACID

2020 ◽  
Vol 55 ◽  
pp. 10-15
Author(s):  
Katerina I. Panova ◽  
◽  
Nicolay N. Pravdin ◽  
Аnatoliy О. Kiryanov ◽  
◽  
...  
Keyword(s):  
Nitric Acid ◽  
Phosphoric Acid ◽  
Raw Materials ◽  
Raw Material ◽  
Material Component ◽  
High Degree

In the process of decomposition of phosphate raw materials, the dynamics of transformation of its constituent mineral phosphoric components: fluorapatite and its derivatives into available for plants dihydro - and hydroorthophosphates of calcium and the influence of a natural organic activator on it are studied.. The composition of the obtained organomineral products was evaluated. The questions of intensification of processing of phosphorite in phosphate-peat systems with additional involvement of nitric acid are considered. The possibilities of reducing the amount of acidic reagents to 50% are shown, while guaranteeing a high degree of use of the target raw material component (94%) and the absence of waste.

Preparation of the System of BaO-MgO-Al2O3-TiO2 Acid-Resistant Fracturing Proppants

2011 ◽  
Vol 399-401 ◽  
pp. 855-859
Author(s):  
Ting Ting Wu ◽  
Bo Lin Wu
Keyword(s):  
Sintering Temperature ◽  
Raw Materials ◽  
Acid Resistance ◽  
Pressureless Sintering ◽  
Alumina Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Solubility ◽  
Resistance Performance ◽  
Scanning Electron

In order to improve the acid resistance and reduce the apparent density of fracturing proppants, TiO2 powder added in the system of BaO-MgO-Al2O3 fracturing proppants were prepared by the technique of pressureless sintering. The properties of the samples were investigated by the measurements of acid solubility, X-ray diffraction and scanning electron microscopy. The results show that the acid solubility of alumina matrix fracturing proppants contenting TiO2 of the 4wt% and BaO/MgO with the ratio of 3:7 is 0.15%. It is an important development in acid resistance performance of fracturing proppants research on laboratory. TiO2 is added to the raw materials and then calcine them to ceramics, which can reduces the sintering temperature, promote the densification and improve acid-resistant property of fracturing proppants.

Effect of Mineral Composition and Sintering Temperature on the Synthetic Cordierite

2014 ◽  
Vol 633 ◽  
pp. 61-64
Author(s):  
Lei Li ◽  
Rui Long Wen ◽  
Xiao Guang Zhang ◽  
Cheng Biao Wang ◽  
Ming Hao Fang ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Flexural Strength ◽  
Mineral Composition ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Temperature Reaction ◽  
Final Phase ◽  
High Temperature Reaction ◽  
Industrial Alumina

Cordierite samples were prepared using quartz sand tailings, industrial alumina and magnesite tailings as raw materials by high-temperature reaction. The influence of mineral composition and sintering temperature on the final phase composition and physical properties of cordierite were studied. The results shown that a large number of cordierite generated at 1300 °C. When the ratio of Al2O3/SiO2 equals to 1.08, the flexural strength of samples increased to 27.66 MPa.

The Preparation and Properties of Clay Bonded Silicon Carbide by Using Silicon Carbide Dusting Powder

2018 ◽  
Vol 922 ◽  
pp. 143-148 ◽  
Author(s):  
Shao Chun Xu ◽  
Zi Jing Wang ◽  
Ya Ming Zhang ◽  
Qiang Zhi ◽  
Xu Dong Wang ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Ball Milling ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Clay Content ◽  
Good Method ◽  
Sintering Additive ◽  
Carbide Refractory ◽  
Milling Method

In this paper, clay bonded silicon carbide was prepared through pressureless sintering process with silicon carbide dusting powder as raw materials and clay as sintering additive. The effects of the ball-milling method, sintering temperature and clay contents on the density, microstructure and mechanical properties of clay bonded silicon carbide refractory were studied. The planetary ball-milling was a good method to improve the density of the green body, and the density was increased simultaneously with an increase of the clay content. The liquid phase derived from low-melting eutectic mixtures of clay could prevent the superlative oxidation of silicon carbide. The mass increment of sintered samples decreased firstly and then increased at the sintering temperature range from 1250 to 1500 °C. The open porosity of samples decreased with the clay addition at a content range from 10 to 30 wt.%. The bending strength of the samples decreased firstly and then increased with the clay addition increasing. The optimum condition for preparing clay bonded silicon carbide with silicon carbide dusting powder was sintering at 1350 °C with 20 wt.% clay, and the obtained sample with a porosity of 24% achieved the bending strength of 78±7 MPa.

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