【摘要】 在242℃,203.2g/1 Na₂O_κ,原液α_κ=3.38,配料α_κ=1.55,溶出85分钟,石灰添加量分别为4.73％、6.75％、10.13％、12.15％和16.2％CaO的条件下,溶出贵州铝土矿。溶出拜耳法赤泥,经X射线衍射、电子显微镜观察及电子探针微区成分分析、化学分析等方法鉴定,查明有10个相。发现了羟基钛酸钙相和含钛水化石榴石相,并求出了他们的分子式: 3CaO·[（Al₂O₃）_0.95（TiO₂）_0.04]·0.94[（SiO₂）_0.34（TiO₂）_0.66]·4.2H₂O和CaTi₂O₄（OH）₂。 C₃AH₆在五个赤泥试样中的含量都是微量的。溶出时,随石灰添加量的增加,赤泥发生如下相变: 还查明了随石灰添加量的增加,Al₂O₃溶出率减少的幅度及碱耗下降的幅度及原因。两种水化石榴石中SiO₂的含量随溶液中SiO₂浓度减少和石灰添加量增加而减少。更多还原

【Abstract】 Ten phases of the red mud digested from Guizhou bauxite were determined by means of chemical analysis, quantitative EPMA, SEM and x-ray diffraction. The co- nditions of the digestion were as follows: Na₂O_k 203.2g/1, 242℃, 85 min, a_k=3.38 （before digestion） and a_k=1.55（burden calculation）. Five determinations were conducted successively. The amounts of CaO contained in the lime added were 4.73%, 6.75%, 10.13%, 12.15% and 16.2% respectively.Among the ten phases, the phases of kassite and the phase of hydrosehorlomite had not been found out before. Their molecular formulas were CaTi₂O₄（OH）₂ and 3CaO[（Al₂O₃）_0.95（TiO₂）_0.04] [（SiO₂）_0.34（TiO₂）_0.66]·4.2H₂O There existed only a little C₃AH₆ in the five samples of the red mud. In the process of digestion, as the amount of lime rose, the phases of the red mud changed gradually in the following way: sodalite→cancrinite （alkali cancrinite）→hydrogrossularite kassite hydrosehorlomite.With the increasing of the amount of lime from 4.73% to 16.2% the phase contents of alkali cancrinite, sodalite, cancrinite and kassite were decreased from 16.3% to 6.2%, 12.6% to 3.5%, 15.5% to 6.1% and 13.5% to 1% respectively. At the same time, the phase contents of hydrogrossularite and hydroschorlomite were increased from 20% to 35.4% and 12% to 40.5% respectively. The content of SiO₂ in the two kinds of hydrogrossularite was decreased as the concentration of SiO₂ in the liquid phase became lower and as the amount of lime was increased. Thus, the extent and the reason for the decrease in the leaching rate and in the consumption of sodium hydroxide were determined by the increase of the amount of lime added.更多还原