高岭石碱石灰的烧结过程

SINTERING PROCESS BETWEEN KAOLINITE AND ALKALI LIME

以CaO–Al2O3–SiO2–H2O和Na2O–CaO–Al2O3–SiO2–H2O体系为对象,通过热力学计算研究了高岭石(Al2O3·2SiO2·2H2O)在碱石灰烧结过程中的反应行为。结果表明:在n(CaO)/n(SiO2)为1的高岭石与氧化钙烧结过程中,形成了不能被碱液溶出的2CaO·Al2O3·SiO2和CaO·Al2O3·2SiO2。在n(CaO)/n(SiO2)为1,1.5或2的高岭石碱石灰烧结反应中,CaO·SiO2会与Na2O·Al2O3反应形成Na2O·Al2O3·2SiO2,从而导致在碱性体系中氧化铝的溶出率降低,而3CaO·2SiO2与2CaO·SiO2不与Na2O·Al2O3反应。CaF2对烧结反应有促进作用。

The characteristics of kaolinite reaction with alkali lime in the sintering process was studied by thermodynamic calculation in CaO- Al2O3- SiO2- H2O and Na2O- CaO- Al2O3 -SiO2- H2O systems. The results show that 2CaO. Al2O3 · SiO2 and CaO ·Al2O3 ·2SiO2 can not be digested in caustic solution when kaolinite reacts with calcium oxide with a molar ratio of CaO to SiO2 of 1. When the molar ratio of CaO to SiO2 is 1, 1.5 or 2 in the sintering process of kaolinite and alkali lime, the reaction between CaO · SiO2 and Na2O· Al2O3 can result in the formation ofNa2O· Al2O3· 2SiO2, which decreases the alumina extraction rate in caustic solution, and the 3CaO ·2SiO2 and 2CaO · SiO2 can not react with Na2O· Al2O3. Calcium fluoride can accelerate the reaction in the sintering process.