MECHANOCHEMICAL ACTIVATION IN THE TECHNOLOGY OF GYPSUM RAW PROCESSING

2011 ◽  
Vol 1 (4) ◽  
pp. 82-86 ◽  
Author(s):  
V. P SUChKOV
Keyword(s):  
Hydrothermal Treatment ◽  
Mechanochemical Activation ◽  
High Strength ◽  
Raw Material ◽  
Recrystallization Process

There has been offered the technology for getting high-strength gypsum binder on the bases of the macroexamination of natural gypsum recrystallization process with hydrothermal treatment. Mechanochemical activation of raw material allows to cut the time and to low the temperature of autoclaving and to avoid the binders grinding.

Facile Fabrication of Flower-Like LLM-105 Three-Dimensional Microstructures

2011 ◽  
Vol 239-242 ◽  
pp. 2942-2945 ◽  
Author(s):  
Jin Chen ◽  
Li Li Wang ◽  
Guang Cheng Yang ◽  
Zhi Qiang Qiao ◽  
Fu De Nie
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Raw Material ◽  
Differential Scanning Calorimetric ◽  
Recrystallization Process ◽  
X Ray ◽  
Facile Fabrication ◽  
Lower Temperature ◽  
Scanning Electron ◽  
Poor Solvent

Flower-like LLM-105 three-dimensional microstructures, which consisted of LLM-105 microrods with rectangular cross-sections, were prepared via a smiple template- and surfactant-free recrystallization process using [Bmim]CF3SO3as good solvent and water as poor solvent. A tentative mechanism for the growth of the flower-like LLM-105 three-dimensional microstructures was proposed on the basis of the analysis of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Comparing with LLM-105 raw material, the thermal decomposition took place at lower temperature and the weight loss has increased for the flower-like three-dimensional microstructures in the differential scanning calorimetric/thermogravimetric (DSC/TG) measurements.

scholarly journals Aplicação de óxidos mistos de molibdênio, vanádio, tungstênio e cobre como catalisadores na produção do ácido acrílico

2020 ◽  
Author(s):  
◽  
W. M. Fantim
Keyword(s):  
Block Copolymer ◽  
Acrylic Acid ◽  
Hydrothermal Treatment ◽  
Crystalline Phase ◽  
Heterogeneous Catalysts ◽  
Raw Material ◽  
Oxide Content ◽  
Propene Oxidation ◽  
Synthesis Conditions ◽  
Catalyst Composition

Acrylic acid is a product with several applications in the chemical industry, the main one is the production of sodium polyacrylate, a superabsorbent material used in the toiletries manufacture. Currently acrylic acid is obtained from propene oxidation using heterogeneous Mo/Bi and Mo/V oxide-based catalysts. In this process, propene is first oxidized to acrolein, which is then oxidized to acrylic acid. Although this is already a consolidated process, propylene comes from petrochemical sources and thus there is a concern to search for alternative routes to the use of this raw material and one of the possibilities is to synthesize acrolein from glycerol dehydration using specific catalysts. For the project, heterogeneous catalysts were prepared to obtain the acrylic acid, first evaluated in the oxidation of acrolein and later in the glycerol oxideshydration. Three types of samples were synthesized with different compositions B1- Mo12V4,8W2,4Cu2,2Si8,4; B2-Mo12V2W0,5Si6,2 and B3-Mo12V2,7Si6,2) by four preparation methods, namely by evaporation, evaporation followed by hydrothermal treatment, hydrothermal treatment (TH) and using a block copolymer. For the last two methods a more detailed study was performed to determine the best synthesis conditions (Phase I), and it was found that the total dissolution of the reagents in the mixture before TH resulted in samples with higher crystallinity and less active phase loss in the liquid and the use of a cold dissolved block copolymer contributed to an increase in pore volume. In the second stage, the materials synthesized by the four proposed methods were characterized and evaluated in reactor in acrylic acid production. The samples B1 showed different crystalline phase formation depending on the preparation method used, and in samples B2 and B3 the main phase was identified as a-MoO3, regardless of the method used. The samples synthesized by evaporation followed by TH showed the highest selectivity for acrylic acid formation from acrolein for the same catalyst composition, which may be related to the higher vanadium oxide content present in samples identified by FRX and the formation of the crystalline phase V0.35Mo4,65O14. The best performance was observed in sample B1-EV+TH with selectivity of 50.59% and 3.61% for acrylic acid in the processes from acrolein and glycerol, respectively

scholarly journals High strength glass-ceramics sintered with coal gangue аs а raw material

2019 ◽  
Vol 51 (3) ◽  
pp. 285-294
Author(s):  
Dang Wei ◽  
H.-Y. He
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
Glass Ceramics ◽  
High Strength ◽  
Coal Gangue ◽  
Raw Material ◽  
Sintering Process ◽  
Forming Process ◽  
Sintered Glass ◽  
Utilization Ratio

High strength lightweight glass-ceramics were fabricated with coal gangue and clay as main raw materials. The utilization ratio of coal gangue, the ratio of the coal gangue with clay, mineralization agents, forming process and sintering process on the properties of the fabricated glass-ceramics were optimized. The utilization ratio of coal gangue reached 75, and the ratio of coal gangue to clay was 3/1, as an optimal property was observed. The optimal sintering temperature was found to be 1370?C. At this optimal temperature, the sintered glass-ceramics showed the main phase of mullite and spindle and so showed high strength, low density, and low water absorbance. The appropriate amounts of codoping of the TiO2, ZnO, and MnO2/dolomite as mineralization agents obviously enhanced the properties of the glass-ceramics. Process optimizations further determined reasonable and optimal process parameters. The high strength lightweight glass-ceramics fabricated in this work may be very suitable for various applications including building materials, cooking ceramics, and proppant materials, et al.

scholarly journals The influence of metahalloysite addition on tobermorite formation studied by X-ray powder diffraction and scanning electron microscope

2018 ◽  
Vol 163 ◽  
pp. 05008
Author(s):  
Anna Skawińska
Keyword(s):  
Phase Composition ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Hydrothermal Treatment ◽  
Powder Diffraction ◽  
Quartz Sand ◽  
Raw Material ◽  
Model Systems ◽  
X Ray ◽  
Scanning Electron

This paper presents the results of the studies carried out in the model systems and concerning the tobermorite synthesis with an addition of metahalloysite. Quartz sand and quicklime were the main raw material constituents. The mixtures in the form of slurries underwent hydrothermal treatment with an addition of metahalloysite (5%, 10%, 15%, 20% and 30%) for 4 hours and 12 hours. The resultant composites were analysed for their phase composition using X-ray powder diffraction. The microstructure was examined using the Scanning Electron Microscope. Tobermorite was the principle reaction product. When 30% metahalloysite was added to the mixture containing CaO and SiO2, the formation of katoite was found.

Mechanochemical Activation of Polymetallic Ore and Further Selective Floatation

2020 ◽  
Vol 844 ◽  
pp. 65-76
Author(s):  
Olena Svietkina ◽  
Kostiantyn Bas ◽  
Jamil Haddad ◽  
Kyrylo Ziborov ◽  
Valentyna Olishevska
Keyword(s):  
Interlayer Space ◽  
Mechanochemical Activation ◽  
Process Intensification ◽  
Raw Material ◽  
Octahedral Layer ◽  
First Case ◽  
Loose Packing ◽  
Elementary Constituent ◽  
Chlorhydric Acid ◽  
Polymetallic Ore

It has been demonstrated that shock-vibrating activation of minerals is a prospective method to impact the ore; it may be used to intensify chemical and physical-chemical processes of mineral raw material processing and preparation. Differences in the composition and phase properties, obtained both in terms of continuous and periodic modes, are in the fact that in the first case loadings deal with interlayer space preserving layered nature of the mineral. When the mode is continuous, then the disturbances cover the octahedral layer though elementary constituent – tetrahedrons – are preserved. It has emerged that the most important advantage of high reacting capability of activated minerals is in the fact that leaching of some ores may be performed in chlorhydric acid at the expense of transformation of some silicate components into a specific state – loose packing of basic silicate chain. Consequently, shock-vibrating activation has become a basis to develop a method of leaching process intensification as well as a method to control phase formation.

Hydrothermal grain pre-processing and ultra-fine milling for the production of durum wheat flour fractions with high nutritional value

2017 ◽  
Vol 24 (3) ◽  
pp. 242-250 ◽  
Author(s):  
Roberto Ciccoritti ◽  
Giovanna Terracciano ◽  
Alessandro Cammerata ◽  
Daniela Sgrulletta ◽  
Viviana Del Frate ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Hydrothermal Treatment ◽  
Wheat Flour ◽  
Nutritional Value ◽  
Fine Fraction ◽  
Raw Material ◽  
Air Classification ◽  
The Difference ◽  
Ultra Fine Grinding ◽  
Water Extractable

This work describes a process for producing durum wheat flour fractions with high potential nutritional value using grain pre-milling hydrothermal treatment and ultra-fine grinding (micronization), coupled with air classification. The difference of bioactive value of the flour fractions in relation to dietary fibre and phenolic compounds was monitored on four durum wheat cultivars by analysing total arabinoxylans, water extractable arabinoxylans and 5- n-alkylresorcinols. The extractability of the analysed compounds was most significantly affected by hydrothermal treatment. On average, the hydrothermally treated kernels compared with the untreated ones presented a marked increase of water extractable arabinoxylans and alkylresorcinols (about 25 and 48%, respectively), whereas slightly lower total arabinoxylans content (about 9%) was detected. The air classification applied on micronized kernels produced two flour fractions, coarse and fine, with the last showing, irrespective of the hydrothermal treatment, an increment of alkylresorcinols (24 and 22% in untreated and treated samples) and of total arabinoxylans (13 and 20% in untreated and treated samples) in comparison with the coarse one. The fine fraction (particles ≤ 120 µm), resulting richer in bioactive compounds, provides an interesting raw material to enrich traditional semolina in which, due to the removal of the external layers, the losses of total arabinoxylans and of alkylresorcinols were more than 60 and 90% alkylresorcinols, respectively, if compared with whole wheat grain.

Experimental Study on Stainless Steel Slag Used in Ceramic Making

2010 ◽  
Vol 105-106 ◽  
pp. 758-760 ◽  
Author(s):  
Yan Bing Zong ◽  
Yu Li ◽  
Da Qiang Cang
Keyword(s):  
Stainless Steel ◽  
Steel Slag ◽  
High Strength ◽  
National Standards ◽  
Raw Material ◽  
Added Value ◽  
Building Ceramic ◽  
Stainless Steel Slag ◽  
Ceramic Samples ◽  
Dta Curves

Composition of stainless steel slag was compared with that of ceramic paste first. DTA curves of ceramic samples were obtained to determine the firing temperature schedule. It is concluded that the stainless steel slag mixed with certain chemically pure materials can serve as raw material for the production of high added value ceramics. Pilot plant scale tests show that the principal crystal phase is diopside, contributing to the making of high strength and high density ceramics. Heating rate, cooling rate and holding time should be controlled appropriately during sintering process for the sake of forming and growth of crystals. The total performance detection of ceramic samples accords with national standards in China when stainless steel slag is used to sinter calcium-magnesium-silicon type ceramic in roller kiln. The proportion of stainless steel slag is 45% during pilot tracey. Dissolution rate of chromium during stainless steel slag used as mainly diopside type of building ceramic is only 25.17 mg/kg ceramic, which resolves the harmless of chromium. This work provides a feasible and effective way for resource of stainless steel slag.

scholarly journals Improvement in mechanical properties in AlN-h-BN composites with high thermal conductivity

2021 ◽  
Author(s):  
Zetan Liu ◽  
Shiqiang Zhao ◽  
Tian Yang ◽  
Ji Zhou
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Hexagonal Boron Nitride ◽  
Relative Dielectric Constant ◽  
High Strength ◽  
Secondary Phase ◽  
High Thermal Conductivity ◽  
Raw Material ◽  
Composite Ceramics ◽  
Powder Particles

AbstractIt is possible to improve the machinability of aluminum nitride-hexagonal boron nitride (AlN-h-BN) ceramics while maintaining high strength and high thermal conductivity. The composite ceramics with 0–30 wt% BN as secondary phase were prepared by hot pressed sintering, using yttrium oxide (Y2O3) as sintering aid. The phase composition, density, microstructure, mechanical properties, thermal conductivity, and dielectric properties were investigated. The sintering additives were favorable to purify the grain boundaries and improve densification, reacting with oxide impurities on the surface of raw material powder particles. The optimum BN content improved the flexural strength and fracture toughness of composite ceramics with 475 MPa and 4.86 MPa·m1/2, respectively. With increasing the amount of BN, the thermal conductivity and hardness of composites gradually decreased, but the minimum value of thermal conductivity was still 85.6 W·m−1·K−1. The relative dielectric constant and dielectric loss tangent of the samples ranged from 6.8 to 8.3 and from 2.4 × 10−3 to 6.4 × 10−3, respectively, in 22–26 GHz.

scholarly journals NON-PLASTIC RAW MATERIALS FOR THE PRODUCTION OF CONSTRUCTION CERAMICS

2020 ◽  
Vol 3 (4) ◽  
pp. 31-38
Author(s):  
V. Men'shikova ◽  
L. Demina
Keyword(s):  
Raw Materials ◽  
Earth Metal ◽  
High Strength ◽  
Ceramic Materials ◽  
Component Composition ◽  
Magnesium Carbonate ◽  
Raw Material ◽  
Building Ceramic ◽  
Alkaline Earth Metal Oxides ◽  
The Cost

research by some scientists shows that the most expensive element in the manufacture of construction ceramics are clay materials, in particular kaolins. They allow getting products with high strength, but at the same time increase significantly the mass refractoriness. In this connection, a significant amount of melt is added or the firing temperature is increased. Of course, this leads to an increase in the cost of products. In Russia, the reserves of these raw materials are insufficient and it is advisable to look for new non-traditional types of raw materials. There is a need to adjust the component composition of ceramic masses and use non-plastic raw materials. An example is natural wollastonites or their analogues in the form of diopside, which are a little-used type of mineral raw material. In the Siberian region, there are several deposits of non-plastic varieties of raw materials for the production of fired construction products. The most famous are the deposits of the Slyudyansky and Sayan districts. The authors present the results of analysis of diopside rocks, where the chemical, mineral compositions and behavior of samples under heating are studied. The absence of alkali and alkaline earth metal oxides in diopsides was determined. The content of iron oxide in the amount of 0.1% indicates the purity of the raw material. More than half of the composition is occupied by silica, which is 53% and 58% in the rocks of the Burutuysky and Sayan deposits, respectively. The basis of the mineral composition of the samples is diopside, with the presence of quartz, calcite, mica and magnesium carbonate. This range of minerals is traditional in many charges of ceramic materials. Therefore, the possibility of using diopside rocks in the production of building ceramic materials is quite high.

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