低钙铝酸钙熟料的物相转变和浸出性能

Phase Transformation and Leaching Property of Low-Lime Calcium Aluminate Clinker

以分析纯CaCO_3,Al_2O_3和SiO_2为原料,研究了n_(CaO)/n_(Al2O3)=1.0,w_(Al2O3)/w_(SiO2)=3.0时物料的熔化温度以及熟料的物相组成、自粉化性能和氧化铝浸出性能.结果表明:物料熔化温度为1 392℃;烧结温度为1 350℃时熟料物相为CaAl_2O_4,Ca_(12)Al_(14)O_(33)和γ-Ca_2SiO_4,自粉化性能和氧化铝浸出性能良好,氧化铝浸出率为93.37%;1 400℃物料局部熔化,非均相的形成造成物料扩散受阻和物相分布不均匀,阻止β-Ca_2SiO_4向γ-Ca_2SiO_4转化,熟料自粉化性能变差,且有Ca_2Al_2SiO_7生成,二者均使氧化铝浸出性能变差,氧化铝浸出率仅为74.50%;1 450℃物料完全熔化,熟料自粉化性能和氧化铝浸出性能得到改善.

The melting temperature, mineral phases, pulverization and alumina-leaching properties of clinkers were studied by using analytical reagent CaCO3, A12O3 and SiO2 as raw materials. The molar ratio of CaO to A12O3 is 1.0 and the mass ratio of A12O3 to SiO2 is 3.0. The results showed that the melting temperature of the sample is 1 392 ℃. The clinker sintered at 1 350 ~（2 is composed of CaA12O4, Ca12 All4 033 and y-Ca2SiO4, which has good pulverization property and alumina leaching rate of 93.37%. The materials melt locally and turn into heterogeneous phases at 1 400 ℃, which blocks the elemental diffusion, results in non- homogeneous phases, and inhibits the conversion of β-Ca2SiO4 to Y-Ca2SiO4. The formation of Ca2A12SiO7 and deterioration of pulverization property sintered at 1 400 ℃ are the main reasons for the low alumina leaching rate of 74. 50%. The clinker sintered at 1 450 ℃ melts completely, which improves the pulverization property and the alumina leaching property of clinker.