Crystalline Silica
Mostrando 1-12 de 55 artigos, teses e dissertações.
-
1. Microstructural characteristics, properties, synthesis and applications of mullite: a review
Abstract Mullite, an intermediate phase of the binary alumina-silica system, is one of the most important phases of ceramic products containing alumina and silica in the initial composition. Its stoichiometry ranges from 3Al2O3.2SiO2 (3:2) to 2Al2O3.SiO2 (2:1) and its crystalline structure is orthorhombic, characterized by the presence of octahedral chains o
Cerâmica. Publicado em: 2022
-
2. Reordering of Depolymerized Silicates as Adsorbents for Large Nitrogen Compounds
The adsorption capacities of two synthesized zeolites (crystalline ZSM-5 and semi-crystalline faujasite Y) for a mixture of indole, quinoline and carbazole were studied. The different samples obtained show different crystalline degree, mesoporosity and Si/Al ratios. The synthesis procedure is based on the simultaneous depolymerization of a mixture of high su
J. Braz. Chem. Soc.. Publicado em: 2021-01
-
3. Síntese de pigmentos de níquel utilizando areia descartada de fundição como fonte de sílica
Resumo Sintetizaram-se pigmentos do sistema Zn2-xNixSiO4 variando a proporção molar de zinco e níquel, partindo da estrutura willemita (Zn2SiO4) à olivina (Ni2SiO4), usando areia descartada de fundição (ADF) e sílica comercial como fontes de SiO2. A ADF foi caracterizada por análise química e DRX. A síntese dos pigmentos seguiu rota cerâmica, com
Cerâmica. Publicado em: 14/11/2019
-
4. An Alternative and Simple Method for the Preparation of Bare Silica Nanoparticles Using Sugarcane Waste Ash, an Abundant and Despised Residue in the Brazilian Industry
Sugarcane waste ash, a Si-rich waste product, is generated in large quantities and creates a serious disposal problem in the Brazilian ethanol-sugar industry, affecting the environment and public health. Here, a simple method capable of generating bare silica nanoparticles utilizing this residue is demonstrated. Firstly, the crystalline silica present in sug
J. Braz. Chem. Soc.. Publicado em: 04/07/2019
-
5. Fe3O4-TiO2 and Fe3O4-SiO2 Core-shell Powders Synthesized from Industrially Processed Magnetite (Fe3O4) Microparticles
The interest for core-shells has been increased in the recent years due to their improved and modifiable properties. In this work, Fe3O4-TiO2 and Fe3O4-SiO2 core-shells were successfully synthesized from an industrially produced magnetite-rich powder with micro- and nanometric particle sizes, superparamagnetic behavior and saturation magnetization of 49 emu/
Mat. Res.. Publicado em: 09/05/2019
-
6. Avaliação da eficácia de sistema de ventilação local exaustora utilizado no controle de sílica cristalina em indústria de borracha de silicone
Resumo Introdução: os sistemas de ventilação local exaustora (SVLE) podem ser utilizados para controlar a exposição ocupacional a agentes químicos. Contudo, muitas vezes são indevidamente concebidos, instalados ou operados, tornando-se ineficazes. Objetivo: avaliar a eficácia de um SVLE empregado para controle da sílica cristalina utilizada na pr
Rev. bras. saúde ocup.. Publicado em: 25/02/2019
-
7. A novel thermal plasma-based technology for submicronic silicon carbide production at pilot scale
Resumo Pó submicrométrico de carboneto de silício foi sintetizado em um novo reator piloto de tocha a plasma por radiofrequência. Os precursores foram pós de cinza de pirólise e sílica com tamanhos micrométricos. A taxa de massa do pó de precursor variou na faixa de 600-2500 g/h. O tempo máximo do teste foi de aproximadamente 3 h. Com o objetivo de
Cerâmica. Publicado em: 2019-01
-
8. Evaluation of the Toxicity of Silver/Silica and Titanium Dioxide Particles in Mammalian Cells
ABSTRACT The increasing concern over the spread of diseases has lead to a high consumption of antimicrobial additives in the medical and industrial fields. Since these particles can lixiviate from loaded materials, the contact between this additive and mammalian cells can occur during manufacture, use and disposal of the products. Silver on fumed silica (AgN
Braz. arch. biol. technol.. Publicado em: 14/11/2018
-
9. Preparation and Characterization of Mullite-Alumina Structures Formed "In Situ" from Calcined Alumina and Different Grades of Synthetic Amorphous Silica
The in situ reaction between alumina and silica to obtain mullite (Al6Si4O13) can be significantly affected by using synthetic amorphous silica (SAS) sources instead of crystalline ones (quartz and cristobalite). For instance, SASs promote early mullite formation (below 1300°C) and greater densification during sintering. This paper reports the "in situ" for
Mat. Res.. Publicado em: 12/03/2018
-
10. Crystallization of Zeolite A Coatings from Natural Zeolite
An investigation was carried out to determine the possibility of preparing coatings of synthetic zeolites on stainless steel from mixtures containing natural zeolite. Hydrothermal synthesis was applied and the coatings obtained were characterized by various techniques. It was observed that crystalline zeolite A coatings could be prepared from natural clinopt
Mat. Res.. Publicado em: 10/11/2016
-
11. Yerba Mate Tea Extract: a Green Approach for the Synthesis of Silica Supported Iron Nanoparticles for Dye Degradation
This work describes a green approach to the synthesis of iron nanoparticles supported in silica using tea extract of the South American plant yerba mate (Ilex paraguariensis). Catalysts with different iron contents were obtained according to the reaction conditions employed. Characterization by X-ray powder diffraction (XRD) and scanning electron microscopy
J. Braz. Chem. Soc.. Publicado em: 2016-11
-
12. Nucleation and growth process of sodalite and cancrinite from kaolinite-rich clay under low-temperature hydrothermal conditions
The synthesis of low-silica zeotypes by hydrothermal transformation of kaolinite-rich clay and the nucleation and growth processes of sodalite and cancrinite in the system Na2O-Al2O3-SiO2-H2O at 100 °C were investigated. The synthesis products were characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Fourier transform infr
Mat. Res.. Publicado em: 01/02/2013