中低品位铝土矿石灰拜耳法溶出的研究

对铝硅比为5.36的一水硬铝石型铝土矿进行了常规拜耳法和石灰拜耳法的溶出对比研究,主要分析了石灰添加量和预脱硅对铝土矿溶出赤泥成分的影响.结果表明,随着石灰添加量的增加,溶出赤泥的铝硅比呈明显的线性上升趋势,而钠硅比则呈下降趋势,且钙硅比小于2.0时,钠硅比呈近似直线迅速下降,当钙硅比大于2.0时,钠硅比变化逐渐变缓;石灰拜耳法溶出赤泥物相主要以水合铝硅酸钙为主,而常规拜耳法溶出赤泥主要以水合铝硅酸钠为主.预脱硅4 h可使溶出赤泥铝硅比从1.53降低到1.43,钙硅比可从0.28降低到0.24.

Study on Digestion of Chinese Middle/Low Grade Bauxite in Lime Bayer Process

Lime is used widely in the Bayer process, which plays an important role in various applications. In particular, it can minimize soda loss in red mud. The conventional and lime Bayer processes using diasporic bauxite (w(Al2O3/w(SiO2):5.36) were contrastively investigated. The effects of lime addition and pre-desilication on the composition of red mud were mainly studied. The results showed that the x(Al2O3/x(SiO2) in red mud increases linearly but the x(Na2O)/x(SiO2) decreases obviously with lime charge and that the main constituent of red mud in lime Bayer and conventional processes are 3CaO · Al2O3 · xSiO2 · nH2O and Na2O · Al2O3 · xSiO2 · nH2O by which a big amount of soda will be lost, respectively. After pre-desilicating for 4 h, the x(Al2O3)/x(SiO2) and x(Na2O)/x(SiO2) in red mud decrease from 1.53 to 1.43 and 0.28 to 0.24, respectively.