Prospects of generation of high technologies of recycling of ash-and-slag waste of thermal power stations
The aim of our investigation was definition of the high technology directions of processing and recycling of ash waste and slags of thermal power stations. As a result of research compoundings of preparation are developed and experimental samples of ceramics (including porous ceramics), protectively-decorative coverings, glazes, enamels and engobes, porous ceramics, refractories, facing tiles are received.
High infrared radiance glass-ceramics obtained from fly ash and titanium slag.
A new glass-ceramic was synthesized by crystal growth from a homogenous glass obtained by melting a mixture of fly ash collected from a power plant in Hebei province of China, titanium slag collected from a titanium factory in Sichuan province of China, and MgCO(3) as an additive. According to the measurement results of differential thermal analysis, a thermal treatment of nucleating at 850 degrees C for 2h and crystallizing at 985 degrees C for 1.5h was used to obtain the crystallized glass. X-ray diffraction and scanning electron microscopy measurements showed that the main crystalline phase of this material was iron-ion substituted cordierite, (Mg,Fe)(2)Al(4)Si(5)O(18), which is homogeneously dispersed within the parent glass matrix. The infrared radiance and thermal expansion coefficient of this material have been examined, and the results demonstrate that this glass-ceramic material has potential for application in a wide range of infrared heating and drying materials.
Crystallization behaviour in the system MgOAl2O3SiO2
Abstract Several glasses were prepared in the MgOAl2O3SiO2 system with different compositions within the formation zone for cordierite. The samples were examined after crystallization to investigate the influence of the composition on the phases formed. Dilatometric measurements were performed on the glasses and the results compared with those relative to stoichiometric cordierite. The nature of the excess component actually changes the stability ranges of cordierite μ and α, and the presence of sillimanite and forsterite is also revealed in samples containing an excess of alumina and magnesia, respectively. For the glass with composition 2MgO · 2Al2O3 · 5SiO2, corresponding to stoichiometric cordierite, the crystallization kinetics have been studied by both the non-isothermal method, based on differential thermal analysis and the isothermal method, based on diffractometric measurements. For the crystallization of the cordierite μ-phase, the calculated activation energy with non-isothermal method is Ea = 85 ± 5 kcal/mol, and the reaction order is n = 0.98 ± 0.1, while for the cordierite α-phase Ea = 135 ± 5 kcal/mol and n = 0.90 ± 0.1. The values for Ea(α) and n(α) determined by the isothermal method are 114 ± 20 kcal/mol and 1.2 ± 0.2, respectively. The value of n is consistent with surface growth of the crystallites.