New Dispersants for the Preparation of Y_2O_3 Spherical Powders by Homogeneous Precipitation at High Temperature

Spherical monodispersed and submicron-sized Y203 powders were successfully synthesized through the urea homogeneous precipitation method adding PVA, PVP, or PVA and PVP compound （PVA/PVP） as the dispersant which generated no impurity phases after calcining. The productivity is up to 60% at 107 ±2 ℃ for 3.5 h in an oil bath. The structure, phase composition and evolution, morphology and specific surface area of Y203 precursor and the calcined powders were explored by means of XRD, TG/DTA, FTIR, SEM, TEM and Micropore analyzer （BET）. The spherical particle size of the powders calcined at 900 ℃ for 2 h was 330-350 nm. In this study, 15.5 Wt.% PVA, 8.5 Wt.% PVP or the mixture of both is in favor of enhancing the dispersity of the products. Based on what we have already achieved, it is rather sinificant to advance this research.

模拟再生粗骨料及再生混凝土的制备与性能研究

为提高废弃混凝土资源化利用率,使用再生骨料制备再生混凝土,解决废弃混凝土的资源与环境问题。针对再生骨料来源复杂,采用三种不同强度等级的原生混凝土模拟制备再生粗骨料,测试其物理性能,分析其所制备混凝土的力学性能与耐久性能。试验结果表明:原生混凝土经过破碎加工处理后所制得的再生骨料,与天然再生粗骨料物理性能相当,然而,相较于天然骨料,其吸水率和压碎指标较大,而堆积密度和表观密度较小。再生粗骨料制得的混凝土的立方体抗压强度、轴心抗压强度与弹性模量相较于天然混凝土有所下降,而电通量有所提升。原生混凝土强度等级越高,骨料与水泥浆体的粘结性越好,制得的再生粗骨料表面粘附着越多的残余砂浆,使得再生粗骨料的物理性能下降,进而影响了再生混凝土的力学性能与耐久性。

混凝土废泥浆再生利用研究

通过C-S-H废浆不同用量、含固量、胶材用量及掺合料、促凝剂掺量的再生混凝土砖优选试验,为解决商品混凝土生产过程中废渣做出了有益探索,实现了商品混凝土无废排放生产的全链闭环,有效推进了商品混凝土真正意义上绿色建材化可持续生产。