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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Novel Colloidal Silica Technology For In Situ Spinelization in MgO-Containing Refractories

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Author(s):
Rafael Salomão [1] ; Leandro Fernandes [2] ; Andreas Sundblom [3] ; Peter Greenwood [4] ; Isabela Santos Martinatti [5] ; Paulo Roberto Teruo Tiba [6]
Total Authors: 6
Affiliation:
[1] Universidade de São Paulo. Escola de Engenharia de São Carlos. Departamento de Engenharia de Materiais - Brasil
[2] Universidade de São Paulo. Escola de Engenharia de São Carlos. Departamento de Engenharia de Materiais - Brasil
[3] Nouryon AB - Suécia
[4] Nouryon AB - Suécia
[5] Nouryon South America - Brasil
[6] Nouryon South America - Brasil
Total Affiliations: 6
Document type: Journal article
Source: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 27, 2024-03-29.
Abstract

This study used an aqueous dispersion of silanized colloidal silica (SCS), whose particles’ surfaces were modified with an epoxysilane-based coupling agent, as the liquid medium and binder for MgO-Al2O3-containing suspensions. Fine calcined alumina and magnesia sinter particles were dispersed in SCS to form a 65 vol% solids suspension. Equivalent silica-free compositions containing calcium aluminate cement or unsilanized colloidal silica were tested as references. After mixing, the SCS-suspension showed low viscosity and suitable workability and, after curing, a thin protective coating of magnesium silicate hydrate (MSH) was formed, thus preventing MgO hydroxylation and improving bonding strength, generating green-dried structures of significant flexural strength (8 MPa). During initial heating, the decomposition of MSH and the softening of amorphous silica particles reduced the overall expansion of spinel (MgAl2O4) formation. After sintering at 1600ºC, the structure showed intense densification (total porosity of 8%) high flexural strength (73 MPa) and large spinel crystals surrounded by a thin layer of amorphous silica and magnesium silicates. (AU)

FAPESP's process: 18/19773-3 - Microporous castable refractories in the Al2O3-MgO-CaO system for thermal insulation above 1200ºC
Grantee:Rafael Salomão
Support Opportunities: Scholarships abroad - Research
FAPESP's process: 10/19274-5 - Novel methodology for hydrotalcite (Mg6Al2(OH)16CO3.4H2O) synthesis from aqueous suspensions of magnesium oxide (MgO) and aluminum hydroxide (Al(OH)3) and its application in porous ceramics for high temperature thermal insulation
Grantee:Rafael Salomão
Support Opportunities: Research Grants - Young Investigators Grants
FAPESP's process: 22/03655-7 - Reducing energy losses in industrial processes with high-efficiency thermal insulation of microporous castable calcium silicate produced from elements of biomass: eggshells and rice husk ash
Grantee:Rafael Salomão
Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants