Producing Clay-Coated Quartz Powders for Semidry Pressing of Wall Ceramics

1998 ◽  
Vol 520 ◽  
Author(s):  
G.N. Kryukova ◽  
P.A. Simonov ◽  
G.I. Storozhenko ◽  
G.V. Boldyrev
Keyword(s):  
Mechanochemical Activation ◽  
Raw Materials ◽  
Low Grade ◽  
High Quality ◽  
Processing Steps ◽  
Semidry Pressing

ABSTRACTThis paper discusses the potential of mechanochemical activation of low grade raw materials with carbonaceous inclusions to achieve high-quality building ceramics. The procedure proposed enabled us to produce clay-coated quartz powders thus facilitating further processing steps of semidry pressing and firing of the bricks, tiles and flagstones.

Synthesis of Low Viscosity Polydimethylsiloxane Using Low Grade of Octamethylcyclotetrasiloxane

2021 ◽  
Vol 1028 ◽  
pp. 365-370
Author(s):  
Diba G Auliya ◽  
Soni Setiadji ◽  
Zulfi Mofa Agasa ◽  
Fitrilawati ◽  
Norman Syakir ◽  
...  
Keyword(s):  
Ring Opening ◽  
Raw Materials ◽  
Vitreoretinal Surgery ◽  
Production Costs ◽  
Low Grade ◽  
High Grade ◽  
High Quality ◽  
Low Viscosity ◽  
Polymerization Method

Polydimethylsiloxane (PDMS) has been widely used as a vitreous humour substitution in vitreoretinal surgery. Due to its limited availability and increasing domestic needs, the price of PDMS in Indonesia became very expensive. Previously, we reported the synthesized of PDMS from a high grade of monomer of 98% of Octamethylcyclotetrasiloxane (D4) and found that all PDMS samples produced high quality samples similar to that of commercial one. However, by considering the ease of obtaining raw materials and also the production costs, the synthesis of PDMS using monomer which easy to be found in Indonesia and low production costs is needed to be developed. Here, we reported the synthesis of PDMS using low grade of 96% of D4 in order to produce high quality of PDMS with low viscosity that can be used for vitreous humous substitution in vitreoretinal surgery. PDMS samples with low viscosity value of 0.94-1.35 Pa.s have been successfully synthesized from low grade of D4 and MM using ring-opening polymerization method. The yields of PDMS resulted in this research were in the range between 67.27% and 76.26%. From FTIR spectroscopy, it is found that all synthesized samples have structure and functional groups similar to PDMS using high grade of monomer of 98% Octamethylcyclotetrasiloxane (D4). From refractometer and surfgauge measurements, all samples have refractive index in the range of 1,4034-1,4040 and the value surface tension was 21 m.N/m.

Application of mechanical activation to obtain target products in fused periclase and slags processing

2020 ◽  
pp. 33-40
Author(s):  
M. S. Garkavi ◽  
◽  
N. N. Orekhova ◽  
O. E. Gorlova ◽  
E. V. Kolodezhnaya ◽  
...  
Keyword(s):  
Mechanical Activation ◽  
Mechanochemical Activation ◽  
Raw Materials ◽  
Converter Slag ◽  
Particle Surface ◽  
Surface Reactivity ◽  
Low Grade ◽  
Steelmaking Slag ◽  
Target Product ◽  
Active Centers

The article presents the results for obtaining the conditioned target product from metallurgical waste, such as vanadium-containing converter slag, steelmaking slag and magnesium-containing fused periclase, by increasing their particle surface reactivity through mechanical activation at the grinding stage. The paper presents the characteristics of the feed and grinding products and the process flows for the processing of respective technogenic raw materials. The dispersion and reactivity of the finely dispersed product, established by the change in the material wetting heat, and the role of mechanical activation for the subsequent processing and improvement of the resulting product grade are evaluated. Mechanical activation of magnesium oxide powder at the last processing stage for low-grade fused periclase promotes an increase in the energy of surface-active centers of the ground material and an improvement in its electrical insulating properties (as compared with ball grinding). Mechanochemical activation of vanadium slag promotes the formation of homogeneous, well-permeable granules, intensification of redox processes during leaching and obtaining the target product (V2O5 paste) with the mass fraction of vanadium pentoxide of 84–86 %. An increase in the reactivity of the dump steelmaking slag during mechanochemical activation allows obtaining high-activity composite cements with the slag content of up to 20 wt.%.

TECHNOLOGICAL ASPECTS OF HIGH QUALITY RAW MATERIAL OBTAINING FOR PECTIN PRODUCTION

1970 ◽  
pp. 47-50
Author(s):  
I. A. Ilina ◽  
I. A. Machneva ◽  
E. S. Bakun
Keyword(s):  
Raw Materials ◽  
Thermal Characteristics ◽  
Environmental Safety ◽  
Raw Material ◽  
High Quality ◽  
Temperature Conductivity ◽  
Drying Temperature ◽  
Plant Raw Materials ◽  
Gel Forming Ability

  The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.

scholarly journals Novel Cs2HfCl6 Crystal Scintillator: Recent Progress and Perspectives

Physics ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 320-351
Author(s):  
Serge Nagorny
Keyword(s):  
Recent Progress ◽  
Raw Materials ◽  
Light Output ◽  
Light Yield ◽  
Thermal Conditions ◽  
Pulse Shape Discrimination ◽  
Main Element ◽  
High Quality ◽  
Crystal Sample ◽  
Discrimination Ability

Recent progress in Cs2HfCl6 (CHC) crystal production achieved within the last five years is presented. Various aspects have been analyzed, including the chemical purity of raw materials, purification methods, optimization of the growth and thermal conditions, crystal characterization, defect structure, and internal radioactive background. Large volume, crack-free, and high quality CHC crystals with an ultimate scintillating performance were produced as a result of such extensive research and development (R & D) program. For example, the CHC crystal sample with dimensions ∅23 × 30 mm3 demonstrates energy resolution of 3.2% FWHM at 662 keV, the relative light output at the level of 30,000 ph/MeV and excellent linearity down to 20 keV. Additionally, this material exhibits excellent pulse shape discrimination ability and low internal background of less than 1 Bq/kg. Furthermore, attempts to produce a high quality CHC crystal resulted in research on this material optimization by constitution of either alkali ions (Cs to Tl), or main element (Hf to Zr), or halogen ions (Cl to Br, I, or their mixture in different ratio), as well as doping with various active ions (Te4+, Ce3+, Eu3+, etc.). This leads to a range of new established scintillating materials, such as Tl2HfCl6, Tl2ZrCl6, Cs2HfCl4Br2, Cs2HfCl3Br3, Cs2ZrCl6, and Cs2HfI6. To exploit the whole potential of these compounds, detailed studies of the material’s fundamental properties, and understanding of the variety of the luminescence mechanisms are required. This will help to understand the origin of the high light yield and possible paths to further extend it. Perspectives of CHC crystals and related materials as detectors for rare nuclear processes are also discussed.

scholarly journals Synthesis of high quality 2D carbide MXene flakes using a highly purified MAX precursor for ink applications

2021 ◽  
Author(s):  
Shi-Hyun Seok ◽  
Seungjun Choo ◽  
Jinsung Kwak ◽  
Hyejin Ju ◽  
Ju-Hyoung Han ◽  
...  
Keyword(s):  
Raw Materials ◽  
High Quality ◽  
Max Phases ◽  
Painting Process ◽  
Manufacturing Techniques

A method of pelletizing raw materials was used to tackle unwarranted variations in MXene products depending on the parent MAX phases, manufacturing techniques, and preparation parameters, enabling a direct painting process on various surfaces for ink applications.

Research on Properties of Low Grade Cement-Based Composite Materials Modified by Silica Fume

2012 ◽  
Vol 174-177 ◽  
pp. 751-756
Author(s):  
Zi Fang Xu ◽  
Ming Xu Zhang ◽  
Jin Hua Li
Keyword(s):  
Silica Fume ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Cement Matrix ◽  
Hardened Cement ◽  
Low Grade ◽  
X Ray ◽  
Matrix Microstructure ◽  
Nano Powder ◽  
Strength And Durability

In order to notably improve the mechanical properties and durability of low-grade cement-based material, superfine silica fume was used to modify the cement-based composite based on special perfomance and effects of nano powder. The mechanical performance and durability were investigated.Then the phase compositions,microstructure and morphologies of as-received cement-based composite were studied by X-ray Diffractometer、TGA-DTA and SEM. The results show that： the best formula of raw materials is 1:1:0.025:0.015, and hydration can be accelerated and increasing of hydration products is observed after modification. In the hardened cement matrix, microstructure is very compacted and C-S-H gel forms densed structure, so the structure defect is notably reduced. This means that both strength and durability of cement-based composite are notably improved by the addition of superfine silica fume.

The Preparation of High Quality CIS Films by Spraying Citrate-Capped Cu11In9 Alloy Nanoparticles Ink and RTP Process

2013 ◽  
Vol 787 ◽  
pp. 382-387
Author(s):  
Li Zhou ◽  
Yuan Kui Ding ◽  
Pai Feng Luo
Keyword(s):  
Raw Materials ◽  
Low Cost ◽  
Chalcopyrite Structure ◽  
Alloy Nanoparticles ◽  
System Research ◽  
Spherical Nanoparticles ◽  
Particle Agglomeration ◽  
Energy Band Gap ◽  
High Quality ◽  
Selenization Process

A facile low-cost non-vacuum process for fabrication of high quality CuInSe2(CIS) films is described, which indicates a promising way for the application in thin film solar cells. First, citrate-capped Cu11In9alloy nanoparticles are synthesized by hot-injection method after a system research on the different reaction time and Cu-In ratio of the raw materials. From the TEM and XRD results, we can see that uniform spherical nanoparticles with dominant Cu11In9phase and less particle-to-particle agglomeration are successfully achieved in this study. Then, employing spray and RTP selenization process, high quality CIS films with dense and big grains are obtained, which show the single chalcopyrite structure and the preferred (112) orientation. An energy band gap about 1.01 eV is measured through the absorption spectroscopy measurement in our work.

scholarly journals Impact of Sodium Hexametaphosphate on the Flotation of Ultrafine Magnesite from Dolomite-Rich Desliming Tailings

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 499
Author(s):  
Duong Huu Hoang ◽  
Doreen Ebert ◽  
Robert Möckel ◽  
Martin Rudolph
Keyword(s):  
Ultrafine Particles ◽  
Raw Materials ◽  
Low Cost ◽  
Froth Flotation ◽  
Open Circuit ◽  
Ore Deposits ◽  
Sodium Hexametaphosphate ◽  
Low Grade ◽  
Low Contrast ◽  
The Impact

The depletion of ore deposits, the increasing demand for raw materials, the need to process low-grade, complex and finely disseminated ores, and the reprocessing of tailings are challenges especially for froth flotation separation technologies. Even though they are capable of handling relatively fine grain sizes, the flotation separation of very fine and ultrafine particles faces many problems still. Further, the flotation of low-contrast semi-soluble salt-type minerals with very similar surface properties, many complex interactions between minerals, reagents and dissolved species often result in poor selectivity. This study investigates the flotation beneficiation of ultrafine magnesite rich in dolomite from desliming, currently reported to the tailings. The paper especially focuses on the impact of the depressant sodium hexametaphosphate (SHMP) on the following: (i) the froth properties using dynamic froth analysis (DFA), (ii) the separation between magnesite and dolomite/calcite, and (iii) its effect on the entrainment. As a depressant/dispersant, SHMP has a beneficial impact on the flotation separation between magnesite and dolomite. However, there is a trade-off between grade and recovery, and as well as the dewatering process which needs to be considered. When the SHMP increases from 200 g/t to 700 g/t, the magnesite grade increases from 67% to 77%, while recovery decreases massively, from 80% to 40%. The open circuit with four cleaning stages obtained a concentrate assaying 77.5% magnesite at a recovery of 45.5%. The dolomite content in the concentrate is about 20%, where 80% of dolomite was removed and importantly 98% of the quartz was removed, with only 0.3% of the quartz in the final concentrate. Furthermore, the application of 1-hydroxyethylene-1,1-diphosphonic acid (HEDP) as a more environmentally friendly and low-cost alternative to SHMP is presented and discussed. Using only 350 g/t of HEDP can achieve a similar grade (76.3%), like 700 g/t of SHMP (76.9%), while obtaining a 17% higher magnesite recovery as compared to 700 g/t of SHMP. Interestingly, the proportion of hydrophilic quartz minerals ending up in the concentrate is lower for HEDP, with only 1.9% quartz at a recovery of 21.5% compared to the 2.7% of quartz at a recovery of 24.9% when using SHMP. The paper contributes in general to understanding the complexity of the depressant responses in froth flotation.

Research of pneumatic conveyor for overloading of fuel pellets

2021 ◽  
pp. 88-96
Author(s):  
N. Spodyniuk ◽  
◽  
L. Horbachenko ◽  
Keyword(s):  
Key Words ◽  
Agricultural Sector ◽  
Raw Materials ◽  
Agricultural Waste ◽  
High Quality ◽  
Fuel Pellets ◽  
Energy Consuming ◽  
Loading And Unloading

The constant development of the country's agricultural sector allows the production of biofuels, such as fuel pellets, from agricultural waste - straw, corn and sunflower husks. However, the transportation of fuel pellets is quite energy consuming. The process of loading and unloading, transportation over long distances requires complex mechanized equipment. The use of a pneumatic conveyor for grain reloading will allow to provide high-quality transportation of fuel pellets. The aim of the article was to investigate the operation of the pneumatic conveyor for overloading fuel pellets, to determine the optimal indicators that affect the productivity of the pneumatic conveyor. Since fuel pellets, as raw materials, are structurally similar to cereals, a study of the pneumatic grain conveyor PTZ-25 was conducted. The dependence of the productivity of the pneumatic conveyor on the lifting height h, m and the length of the pipelines L, m was obtained. The obtained results showed that by reducing the length of the pipelines by four times and the lifting height by half, the productivity of the pneumatic conveyor will increase by 1.15 times. Key words: fuel pellets, pneumatic conveyor, productivity

scholarly journals P397 Surveillance in ulcerative colitis: Can we predict the risk for intraepithelial neoplasia?

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S368-S369
Author(s):  
J Estorninho ◽  
P Freire ◽  
S Lopes ◽  
M Ferreira ◽  
M Ferreira ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Disease Duration ◽  
Intraepithelial Neoplasia ◽  
Screening Colonoscopy ◽  
Low Grade ◽  
Surveillance Colonoscopy ◽  
High Quality ◽  
Increased Risk ◽  
History Of ◽  
Low Grade Dysplasia

Abstract Background Ulcerative colitis (UC) has been associated with an increased risk of colorectal cancer (CRC). Although dye spray chromoendoscopy showed superiority to standard colonoscopy in surveillance studies, with the availability of higher-resolution colonoscopes, the utility of chromoendoscopy (CE) has been questioned. We aimed to evaluate the risk of intraepithelial neoplasia (IN) after a high-quality screening colonoscopy (making use of CE or random biopsies (RB) and removing all detected lesions) in a population with longstanding UC and to identify potential risk factors for dysplasia incidence. Methods In a previous study, 145 patients with clinically and endoscopic longstanding (≥8 yr) distal/extensive UC without primary sclerosing cholangitis and/or history of IN were prospectively randomised to undergo CE or RB. In this study, after a median follow-up of 5 additional years, we evaluated subsequent IN incidence in these patients, submitted to surveillance colonoscopy. Patients without high-quality surveillance colonoscopy (with good bowel preparation and cecum intubation) using high-definition were excluded. Results One hundred and twenty-one patients were included. Nine had removed adenomas with low-grade dysplasia in the index colonoscopy. Now, in surveillance colonoscopy, we detected 9 (7.4%) IN: low-grade dysplasia was found in 8 (6.6%) patients and a colorectal adenocarcinoma in 1 (0.008%) patient. After multivariate analysis, IN was significantly associated with older age (68 vs. 52 years, p < 0.05) and higher disease duration (26 vs. 20 years, p < 0.05). No association was found between IN and previous detection of IN in screening colonoscopy sex, the CE or RB use in index colonoscopy, extent of disease, The presence of pseudopolyps, smoking habits, familial history of CRC or maintenance therapy for UC. Conclusion In this study, older patients and higher disease duration were associated with a higher risk of IN in surveillance colonoscopy.

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