Using differential thermal analysis, X-ray phase analysis, electron microscopy, and optical microscopy, the nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied...Using differential thermal analysis, X-ray phase analysis, electron microscopy, and optical microscopy, the nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied. The type of crystallization (homogeneous or heterogeneous, volume or surface) is revealed for each of nine compositions of synthesized glass. It is shown that the first crystalline phase in a volume crystallizing glass is perovskite (CaO·TiO2);in this phase a nucleation of the main phase occurs: melilite (solid solution of gehlenite 2CaO·Al2O3·SiO2 in akermanite 2CaO·MgO·2SiO2). The fundamental characteristics of homogeneous (for a catalizing phase, perovskite) and heterogeneous (for a catalyzed phase, melilite) of crystallization are determined: the steady state nucleation rate Ist, time of unsteady state nucleation τ, crystal growth rate U, and activation energy of frictional flow. The temperature dependences of Ist, τ, and U are obtained. The kinetics of the crystallization of glass is studied and the rates of the surface crystal growth are determined in the glass of nine compositions. The influence of grinding the particles of the original glass on the sequence of deposition of the crystalline phases was studied. Practical recommendations are presented for the use of blast-furnace slag as a raw material for the synthesis of glass and their further utilization.展开更多
含钛高炉渣中钛组分弥散分布于多种矿物相中 ,很难直接用选矿方法分离。在高炉渣中加入 Ca O和 Mn O可使钛富集于充分结晶长大的钙钛矿相中 ,为选矿分离创造必要条件。作者借助多视场图像分析及粘度测定研究了 Ca O、Mn O对钙钛矿相结...含钛高炉渣中钛组分弥散分布于多种矿物相中 ,很难直接用选矿方法分离。在高炉渣中加入 Ca O和 Mn O可使钛富集于充分结晶长大的钙钛矿相中 ,为选矿分离创造必要条件。作者借助多视场图像分析及粘度测定研究了 Ca O、Mn O对钙钛矿相结晶的影响。实验结果表明 :Ca O加入量对钙钛矿结晶及晶体生长有双重影响。加入适量 Ca O,有利于钙钛矿相结晶量的增加 ,但 Ca O加入量过多 ,使熔渣粘度及熔化性温度显著提高 ,反而抑制钙钛矿结晶长大。加入适量 Mn O可显著降低熔渣粘度及熔化性温度 ,促进钙钛矿结晶长大。随 Ca O加入量提高 ,钙钛矿由粗大的树枝晶转变为细小等轴晶 ,说明加入过多 Ca O不利于钙钛矿晶体粗化。展开更多
文摘Using differential thermal analysis, X-ray phase analysis, electron microscopy, and optical microscopy, the nucleation of crystals in glass obtained by blending metallurgical slag with silicon dioxide has been studied. The type of crystallization (homogeneous or heterogeneous, volume or surface) is revealed for each of nine compositions of synthesized glass. It is shown that the first crystalline phase in a volume crystallizing glass is perovskite (CaO·TiO2);in this phase a nucleation of the main phase occurs: melilite (solid solution of gehlenite 2CaO·Al2O3·SiO2 in akermanite 2CaO·MgO·2SiO2). The fundamental characteristics of homogeneous (for a catalizing phase, perovskite) and heterogeneous (for a catalyzed phase, melilite) of crystallization are determined: the steady state nucleation rate Ist, time of unsteady state nucleation τ, crystal growth rate U, and activation energy of frictional flow. The temperature dependences of Ist, τ, and U are obtained. The kinetics of the crystallization of glass is studied and the rates of the surface crystal growth are determined in the glass of nine compositions. The influence of grinding the particles of the original glass on the sequence of deposition of the crystalline phases was studied. Practical recommendations are presented for the use of blast-furnace slag as a raw material for the synthesis of glass and their further utilization.
文摘含钛高炉渣中钛组分弥散分布于多种矿物相中 ,很难直接用选矿方法分离。在高炉渣中加入 Ca O和 Mn O可使钛富集于充分结晶长大的钙钛矿相中 ,为选矿分离创造必要条件。作者借助多视场图像分析及粘度测定研究了 Ca O、Mn O对钙钛矿相结晶的影响。实验结果表明 :Ca O加入量对钙钛矿结晶及晶体生长有双重影响。加入适量 Ca O,有利于钙钛矿相结晶量的增加 ,但 Ca O加入量过多 ,使熔渣粘度及熔化性温度显著提高 ,反而抑制钙钛矿结晶长大。加入适量 Mn O可显著降低熔渣粘度及熔化性温度 ,促进钙钛矿结晶长大。随 Ca O加入量提高 ,钙钛矿由粗大的树枝晶转变为细小等轴晶 ,说明加入过多 Ca O不利于钙钛矿晶体粗化。
