基于密度泛函理论研究K对Li2CO3晶体影响规律

The Effect of K on Li2CO3 Crystals Based on Density Functional Theory

中文关键词:  盐湖Li₂CO₃  K  掺杂  第一性原理  缺陷形成能

英文关键词:Salt lake Li₂CO₃  K  Doping  First-principles  Defect formation energy

中文摘要:

      以盐湖卤水为原料提取并制备Li₂CO₃的过程中,共存离子对其结晶过程影响较大,尤其我国西藏盐湖卤水为原料制备碳酸锂的原料中,K/Li约为0.3左右,所以研究K⁺对Li₂CO₃晶体的影响具有重要意义。通过实验和计算模拟相结合研究不同K/Li条件下K⁺对Li₂CO₃晶体的影响程度,建立晶体中K⁺含量与比表面积关联式。实验结果表明,K⁺的存在对Li₂CO₃的高品质性影响较大,且随着钾离子含量增加,晶体比表面积增大易于吸附杂质离子,表面粗糙度增强,且K⁺存在对碳酸锂晶体的收率影响较大,而当K/Li控制在0.1以内时,K⁺对碳酸锂晶体的影响相对较小。通过第一性原理计算,计算并分析了K掺入碳酸锂晶体中的几何结构、缺陷形成能及态密度,结果表明K原子在碳酸锂晶体中更易替代晶体中的Li原子,K原子的掺入对碳酸锂晶体的晶格参数以及电子结构性质的影响较小。对西藏盐湖高效提锂和制备高附加值碳酸锂晶体提供了理论依据。

英文摘要:

      In the process of extraction and preparation of Li₂CO₃ from salt lake brine,coexisting ions have a great influence on its crystallization process.Especially in the preparation of lithium carbonate from salt lake brine in Tibet,China,K/Li is about 0.3,it is important to study the effect of K⁺ on Li₂CO₃ crystal.In this study,the effects of K⁺ on Li₂CO₃ crystals under different K/Li conditions were studied by combining experiments and computational simulations,and establishing the correlation formula between K^+content in crystal and specific surface area.The experimental results show that the presence of K⁺ has a great influence on the high quality of lithium carbonate,with the increase of potassium ion content,the specific surface area of lithium carbonate crystals increases,and the surface roughness enhances；moreover,the presence of K⁺ has a great influence on the yield of lithium carbonate crystals.However,when K/Li is controlled within 0.1,the effect of K⁺ on lithium carbonate crystals is relatively small.The geometrical structure,defect formation energy and density of states in K doped lithium carbonate crystal were calculated and analyzed.The results show that K atom can easily replace Li atom in lithium carbonate crystal,and the incorporation of K atom has little effect on lattice parameters and electronic structural properties of lithium carbonate crystal.This research provides a theoretical basis for high efficiency lithium extraction from salt lake in Tibet,China,and preparation of high added value lithium carbonate crystals.