The aim of this study was kinetic investigations of aluminum extraction from Ethiopian kaolinite with hydrochloric acid. The effects of extraction parameters, namely, solid-to-liquid ratio (0.05, 0.075, 0.100, and 0.125 g·mL⁻¹), acid concentrations (2, 3, 4, and 5 M), reaction temperature (50, 60, 70, and 80°C), and time (20, 40, 60, 80, 100, 120, 140, 160, and 180 min), on yield of aluminum were investigated. The results revealed that the extraction yield of aluminum increased with increase of acid concentration, reaction temperature, and time and declined with increase of solid-to-liquid ratio. The kinetic analysis of aluminum extraction was evaluated using pseudohomogeneous, nucleation growth (Avrami), and shrinking core models. The results showed that kinetics of aluminum extraction were controlled by surface chemical reaction. The experimental results were well fitted by the shrinking core model of surface chemical reaction with first-order rate. The activation energy and the preexponential factor were 25.40 kJ·mol⁻¹ and 0.949 cm·min⁻¹, respectively. The leached solution samples were crystallized using evaporation and concentrated hydrochloric acid pouring. The volume ratios of concentrated hydrochloric acid to the samples were from 0.30 to 0.90 (v/v). The crystallization efficiency of aluminum chloride hexahydrate crystals increased with volume of hydrochloric acid and crystallization time. The crystallization yield of aluminum chloride hexahydrate crystals reached 90%. This study’s results clearly revealed that Ethiopian kaolinite could be a promising raw material to produce aluminum chloride hexahydrate, which could be used for water treatment application.

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盐酸从埃塞俄比亚高岭石中提取铝的动力学分析

本研究的目的是用盐酸从埃塞俄比亚高岭石中提取铝的动力学研究。萃取参数的影响，即固液比（0.05、0.075、0.100 和 0.125 g·mL ^-1)、酸浓度（2、3、4 和 5 M）、反应温度（50、60、70 和 80°C）和时间（20、40、60、80、100、120、140、160、和 180 分钟），对铝的产率进行了研究。结果表明，铝的提取率随着酸浓度、反应温度和时间的增加而增加，随着固液比的增加而下降。使用拟均质、成核生长 (Avrami) 和收缩核心模型评估铝提取的动力学分析。结果表明，铝萃取动力学受表面化学反应控制。实验结果与一级速率的表面化学反应收缩核模型拟合良好。活化能和指前因子为25.40 kJ·mol ^-1和0.949 cm·min ^-1，分别。使用蒸发和浓盐酸倾倒使浸出溶液样品结晶。浓盐酸与样品的体积比为 0.30 至 0.90 (v/v)。六水氯化铝晶体的结晶效率随着盐酸体积和结晶时间的增加而增加。六水氯化铝晶体的结晶收率达到90%。这项研究的结果清楚地表明，埃塞俄比亚高岭石可能是生产六水氯化铝的有前途的原料，可用于水处理应用。