The intensified leaching behavior of potassium from phosphorus-potassium associated ore in HCl-CaF2 system with surfactant: Part I kinetics and modelling
The intensified leaching behavior of potassium from phosphorus-potassium associated ore in HCl-CaF2 system with surfactant: Part I kinetics and modelling
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DOI：
10.1016/j.seppur.2018.11.025
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发表时间：
2019-04-01
影响因子：
8.6
通讯作者：
Wang, Cunwen
中科院分区：
文献类型：
--
作者：
Liu, Cuncheng;Liu, Sucheng;Wang, Cunwen
研究了不同表面活性剂在HCl-CaF 2体系中对磷钾共生矿中钾的强化浸出行为。结果表明，阴离子表面活性剂能提高钾的溶出度，其中十二烷基硫酸钠（SDS）的效果最好。加入0 ~ 1.25 g/L SDS时，溶出度从89.50%增加到98.01%，加入5.00 g/L SDS时，溶出度下降到91.5%。阳离子表面活性剂只能缩短达到平衡的时间，而非离子表面活性剂则会阻碍钾的浸出。1.25 g/L SDS存在下的强化浸出是由于SDS吸附在矿物颗粒的表面和微孔裂纹上，形成吸附膜，使更多的SiF 4滞留在吸附膜中，产生更多的SiO2，使残留物变得光滑，从而产生更多的HF，使矿石被侵蚀得更彻底。但当SDS用量超过临界胶束化浓度（CMC）时（如5.00 g/L），在残渣表面形成较多的胶束覆盖，阻碍了酸和氟进入矿石内部，溶解分数降低。此外，钾的浸出动力学模型成功地基于改进的收缩核模型，化学反应是速率控制步骤的半经验动力学模型。
The intensified leaching behavior of potassium from phosphorus-potassium associated ore in HCl-CaF 2 system with different surfactants was investigated. It was found that anion surfactants could enhance the dissolution fraction of potassium and sodium dodecyl sulfate (SDS) had the best effect. The dissolution fraction increased from 89.50% to 98.01% with the addition of 0-1.25 g/L SDS, but dropped to 91.5% with 5.00 g/L SDS. The cationic surfactants could only shorten the time to the equilibrium, while the nonionic surfactant would hinder the leaching of potassium. The intensified leaching observed in the presence of 1.25 g/L SDS could be interpreted as follows: SDS was adsorbed on the surface and micro-porous cracks of mineral particles, then the adsorption film was appeared, which leaded to more SiF4 stayed in the adsorption film and more SiO2 produced, indicating the residual became smooth, thereby the ore was eroded thoroughly due to the produce of more HF. But much micelle covering on the residue was formed if the dosage such as 5.00 g/L SDS exceeded the critical micellization concentration (CMC), which hindered acid and fluorine entered into the interior of the ore, indicating dissolution fraction decreased. In addition, the leaching kinetics of potassium was successfully modeled by a semiempirical kinetic model based on the modified shrinking-core model with chemical reaction being the rate-controlling step.