以锆英石为原料、Y2 O3为稳定剂,采用常压烧结工艺,制备了系列的硅酸锆陶瓷,并利用阿基米德法、维氏硬度法、XRD和SEM技术分别对硅酸锆陶瓷的密度、物相变化和显微结构进行了表征.结果表明,不同配比样品的密度随烧结温度的增加仅有较小幅度的增加,随着Y2O3添加量的增加样品维氏硬度先增大再减小,温度升高有助于硬度的提高,样品的物相均由ZrSiO4和稳定ZrO2组成,Y2 O3添加量的增加促进了ZrSiO4的分解和稳定ZrO2的生成,气孔及稳定ZrO2的存在是影响材料密度的重要因素.%Phosphogypsum (PG), an industrial by-production, is generated from the production of phosphoric acid by the wet process, and currently, stored in stockpiles in large quantities without any treatment. The storage of PG, containing heavy metals and presenting a low radioactivity, obviously will cause severe contamination with the time passing. A number of studies had been conducted on the feasibility of PG used for building blocks, this paper presents another method to achieve the optimum formulation of this binder, which consisted of 47% PG, 15% calcined lime,30% fly ash and 8% water. The results obtained by the calculation of exteeme vertex design demonstrate that the bricks successfully satisfied the standard requirements for mechanical testing. The analysis of scanning electron microscopy (SEM) and quantitative X-ray diffraction (XRD) shows that ettringite and calcium sulfate hydrate (C-S-H), form a dense network structure with the fly ash, and was found in the fly ash calcined lime cements pastes,and that might be the main cause to early strength of mortars.
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