Wang Yunshan, Shi Lufang, Li Houli, Wang Yixiao, Wang Zhiying, An Xuebin, Tang Mingzhu, Yang Gang, He Jun, Hu Jing, Sun Yong
National Engineering Research Center of Green Recycling for Strategic Metal Resources, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
Each Energy Technology (Suzhou) Co., Ltd., Suzhou 215021, China.
ACS Omega. 2022 Jul 7;7(28):24561-24573. doi: 10.1021/acsomega.2c02362. eCollection 2022 Jul 19.
In this paper, a clean process based on the steam-mediated reactions for simultaneous HCl and KCl production using the potassium (K)-containing phosphorous rock as a precursor is proposed. Through hydrochloric acid (HCl) leaching, not only the generation of HPO and CaCl (via further precipitation) were realized but also the acid-insoluble residue [phosphorous-rock slag (PS)] rich in elements, that is, K, Al, Si, and so on, in the form of microcline (KAlSiO) and quartz (SiO) was obtained and became readily available for further HCl and KCl generation. Over 95% of the elements, that is, K, Al, and Si, come into the final products, and the overall acid consumption (based on HCl) is significantly reduced (90%) due to recovery of acids. The impacts of the key operational parameters such as temperature, duration, and reagent impregnate ratio were rigorously analyzed via a supervised machine learning approach, and the optimal conditions were determined [reaction temperature, X, 850 °C; reaction duration, X, 40 min; and impregnate ratio (PS over CaCl), X, 2.5] with approximately ±10% uncertainties. Thermodynamic analysis indicates that the introduction of steam to PS + CaCl not only enhances the chemical potential for the formation of HCl and KCl but also provides the transport advantage in continuously removing the generated products, that is, HCl and KCl, out of the system. Molecular simulation indicates that the presence of both steam and SiO in the PS matrix plays critical roles in decomposing PS + CaCl at high temperature. The shrinking core model shows that both the intrinsic kinetics and transport are influential with the activation energy being around 14.63 kJ/mol. The potential reaction pathway is postulated.
本文提出了一种基于蒸汽介导反应的清洁工艺，该工艺以含钾磷矿为前驱体同时生产HCl和KCl。通过盐酸（HCl）浸出，不仅实现了HPO和CaCl（通过进一步沉淀）的生成，还获得了富含钾（K）、铝（Al）、硅（Si）等元素的酸不溶性残渣[磷矿渣（PS）]，其形式为微斜长石（KAlSiO）和石英（SiO），并且易于用于进一步生成HCl和KCl。超过95%的K、Al和Si等元素进入最终产物，并且由于酸的回收，总的酸消耗（基于HCl）显著降低（90%）。通过监督机器学习方法严格分析了温度、持续时间和试剂浸渍比等关键操作参数的影响，并确定了最佳条件[反应温度，X，850℃；反应持续时间，X，40分钟；浸渍比（PS与CaCl之比），X，2.5]，不确定性约为±10%。热力学分析表明，向PS + CaCl中引入蒸汽不仅增强了HCl和KCl形成的化学势，还提供了将生成的产物HCl和KCl连续从系统中移除的传输优势。分子模拟表明，PS基质中蒸汽和SiO的存在在高温下分解PS + CaCl中起关键作用。收缩核模型表明，本征动力学和传输都有影响，活化能约为14.63 kJ/mol。推测了潜在的反应途径。
