贵县式三水铝土矿微量元素地球化学特征及其意义

本文应用微量元素地球化学理论,通过研究区内地层、红土剖面及矿物相中微量元素含量分配特点,结合野外观察结果,得出了本区三水铝土矿的成矿源岩是郁江组地层的结论,为本区找矿提供了新的线索。     

氧化铝种分过程浓度及质量比模型的研究

从种分过程的动力学机理出发,结合实验室实验和生产现场的工业试验,以铝酸钠溶液分解过程的动力学方程为数学模型,利用Simulink软件包建立种分过程的浓度变化的动态模型对种分过程进行模拟,预测不同工艺条件下连续分解槽的氧化铝浓度变化。基于分解槽浓度变化直接影响铝酸钠溶液的分解率,利用模型来研究不同工艺制度下种分过程分解率的变化,同时建立连续分解槽的质量比(Rp)模型,通过Rp模型预测不同工艺条件下种分过程的分解率。研究结果表明：降低初温和降低末温有利于提高分解率;实际生产过程的温度是波动变化的,温度异相位波动比同相位波动对分解率影响更大,故可根据天气状况及时调整种分工艺条件,为分解工艺参数的调整和优化提供一定的参考依据。     

漳浦沿海新生代玄武岩的风化成矿作用

玄武岩红土壳具帝状结构。本文叙述了红土壳各带的岩石、矿物特征,风化过程中元素的迁移和聚散,硅铝分离、铁铝分离在铝土矿形成上的重要意义;用扫描电镜和能谱仪对各带样品作了系统观测;探讨了矿物的风化和演变;认为三水铝石可通过多种方式形成于风化作用的不同阶段。     

以韦帕矿为后加矿的增溶溶出技术

对澳大利亚韦帕矿的溶出性能及以韦帕矿为后加矿的增溶溶出技术进行了实验研究.考察了增溶温度,增溶时间,后加矿加入量对溶出效果的影响,同时对后加矿增溶溶出的矿浆性能进行了对比性研究.结果表明:韦帕矿为三水铝石矿,在200℃以上溶出时,浸出率较高,适宜作为增溶溶出过程的后加矿.以韦帕矿为后加矿,其适宜的增溶溶出条件为:增溶温度195~200℃,增溶时间15~20 min,后加矿的质量分数为15%~20%.后加矿增溶溶出矿浆具有优良的沉降压缩性能.     

石灰对三水铝石型铝土矿低温溶出行为的影响

研究了不同石灰添加量对3种国外三水铝石型铝土矿在145℃时溶出性能的影响规律及其作用机理.国外三水铝石型铝土矿主要由三水铝石、针铁矿、赤铁矿、高岭石和石英等组成,并含有一定的锐钛矿和一水软铝石.研究结果表明,添加石灰能够促进脱硅反应的进行,降低溶出后铝酸钠溶液中二氧化硅的质量浓度,随着石灰质量分数的增加,溶液的硅量指数逐渐提高;添加石灰降低三水铝石型铝土矿的氧化铝溶出率,其与石灰的质量分数呈线性递减关系;石灰促进脱硅产物由水合铝硅酸钠向水化石榴石转变,随着石灰质量分数的增加,溶出液中的苛碱质量浓度逐渐提高,赤泥中碱的质量分数逐渐降低.     

Precipitation of spherical boehmite from concentrated sodium aluminate solution by adding gibbsite as seed

The precipitation of spherical boehmite was studied by surface energy calculations, measurements of precipitation ratios, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The surface energy calculation results show that the (001) and (112) planes of gibbsite surfaces are remarkably stable because of their low surface energies. In addition, the (010) plane of boehmite grows preferentially during precipitation because of its low surface energy. Thus, we propose a method to precipitate spherical boehmite from a supersaturated sodium aluminate solution by adding gibbsite as seed in a heterogeneous system. In this method, gibbsite acts as the preliminary seed and saturation modifier. The results show that the fine boehmite first nucleates on the (001) and (112) planes of gibbsite and then grows vertically on the (001) and (112) basal planes of gibbsite via self-assembly, thereby forming spherical boehmite. Simultaneously, gibbsite is dissolved into the aluminate solution to maintain the saturation for the precipitation of boehmite. The precipitation ratio fluctuates (forming an M-shaped curve) because of gibbsite dissolution and boehmite precipitation. The mechanism of boehmite precipitation was further discussed on the basis of the differences in surface energy and solubility between gibbsite and boehmite. This study provides an environmentally friendly and economical method to prepare specific boehmite in a heterogeneous system.