It was proved that MgO and MicroSilica can react at room temperature, giving a hardened product primarily comprised of Mg （ OH ）2 and Magnesium Silicate Hydrate （ M- S- H ）. The reaction ratio and process and the ...It was proved that MgO and MicroSilica can react at room temperature, giving a hardened product primarily comprised of Mg （ OH ）2 and Magnesium Silicate Hydrate （ M- S- H ）. The reaction ratio and process and the chemical composion of M- S- H were studied and analyzed by QXRD and DTA- TG. The experimental results indicate that much Mg（ OH）2 and less M-S-H were formed at early period. After 7 days there is no change in the quantity of Mg（ OH）2, while M-S-H was increased slowly. The chemical composion of M-S-H would vary with the mix proportion in the hydrution process , but M1.32 SH2.37 is finally the approximute form.展开更多
Although high-performance basic refractory materials play an essential role in state-of-the-art steel-making,magnesia castables have not been widely used until now. A major challenge is that brucite formation（ Mg（ O...Although high-performance basic refractory materials play an essential role in state-of-the-art steel-making,magnesia castables have not been widely used until now. A major challenge is that brucite formation（ Mg（ OH）2） during Mg O hydration causes volume expansion and subsequent cracking—a phenomenon commonly called ＂slaking＂. To overcome problems related to slaking,a new specialty product,Siox X- Mag,has recently been developed for cement-free Mg O castables based on Mg O- SiO 2- H2 O bond. Specimens from industrial-scale-sized blocks after dry-out were characterised by SEM and XRD techniques. Using Siox X- Mag in combination with microsilica,cracking caused by brucite formation is suppressed. The results demonstrate that the dosage of microsilica plays essential roles in the crack formation in large samples. Furthermore,the compatibility of Siox X- Mag with different types of basic aggregates, medium to high-grade dead-burned magnesia and olivine, has also been evaluated. High-performance,self-flowing cement-free Mg O castables have been developed.展开更多
Microsilica-gel bonded bauxite based no-cement refractory castables（NCCs）have been produced using two readily available dispersants.These NCCs were compared to NCC with Siox X-Zero,a purposely-developed product for ...Microsilica-gel bonded bauxite based no-cement refractory castables（NCCs）have been produced using two readily available dispersants.These NCCs were compared to NCC with Siox X-Zero,a purposely-developed product for microsilica-gel bonded no-cement castable systems to control flow properties and setting characteristics.Three mixing and curing temperatures were applied：5℃,20℃and 35℃.The results show that setting-behaviour and mechanical properties strongly vary with the type of dispersant and the curing temperature.However,both setting and strength are less temperature dependent in the castables with Siox X-Zero.Furthermore,the drying and firing of microsilica-gel bonded NCCs were investigated.Since microsilica-gel bond system contains only a small amount of bound water,the castables can be fired at very high heating rates,once the free water has been removed.展开更多
文摘It was proved that MgO and MicroSilica can react at room temperature, giving a hardened product primarily comprised of Mg （ OH ）2 and Magnesium Silicate Hydrate （ M- S- H ）. The reaction ratio and process and the chemical composion of M- S- H were studied and analyzed by QXRD and DTA- TG. The experimental results indicate that much Mg（ OH）2 and less M-S-H were formed at early period. After 7 days there is no change in the quantity of Mg（ OH）2, while M-S-H was increased slowly. The chemical composion of M-S-H would vary with the mix proportion in the hydrution process , but M1.32 SH2.37 is finally the approximute form.
文摘Although high-performance basic refractory materials play an essential role in state-of-the-art steel-making,magnesia castables have not been widely used until now. A major challenge is that brucite formation（ Mg（ OH）2） during Mg O hydration causes volume expansion and subsequent cracking—a phenomenon commonly called ＂slaking＂. To overcome problems related to slaking,a new specialty product,Siox X- Mag,has recently been developed for cement-free Mg O castables based on Mg O- SiO 2- H2 O bond. Specimens from industrial-scale-sized blocks after dry-out were characterised by SEM and XRD techniques. Using Siox X- Mag in combination with microsilica,cracking caused by brucite formation is suppressed. The results demonstrate that the dosage of microsilica plays essential roles in the crack formation in large samples. Furthermore,the compatibility of Siox X- Mag with different types of basic aggregates, medium to high-grade dead-burned magnesia and olivine, has also been evaluated. High-performance,self-flowing cement-free Mg O castables have been developed.
文摘Microsilica-gel bonded bauxite based no-cement refractory castables（NCCs）have been produced using two readily available dispersants.These NCCs were compared to NCC with Siox X-Zero,a purposely-developed product for microsilica-gel bonded no-cement castable systems to control flow properties and setting characteristics.Three mixing and curing temperatures were applied：5℃,20℃and 35℃.The results show that setting-behaviour and mechanical properties strongly vary with the type of dispersant and the curing temperature.However,both setting and strength are less temperature dependent in the castables with Siox X-Zero.Furthermore,the drying and firing of microsilica-gel bonded NCCs were investigated.Since microsilica-gel bond system contains only a small amount of bound water,the castables can be fired at very high heating rates,once the free water has been removed.
