(中南大学 资源加工与生物工程学院，战略含钙矿物资源清洁高效利用湖南省重点实验室，长沙 410083)
摘 要: 探索矿物晶体断裂及晶面暴露机制，对于精准调控矿物表面性质具有重要指导意义。前期提出的断裂键密度Db法，可准确解析具有一种类型断裂键的矿物/材料晶体的断裂机制。然而，对于具有两种及以上类型断裂键的晶体，需要探索新方法。本文以具有3种类型断裂键的锆石晶体为例，采用第一性原理计算与Bader电荷分析，提出基于键级权重的晶面断裂能密度(Sc)方法，快速评估锆石沿各晶面断裂的难易度，揭示晶面暴露规律。晶体化学键键能计算分析表明，锆石晶体中各化学键键能大小顺序为Si—O(6.00 eV)＞Zr—Oβ(2.87 eV)＞Zr—Oα(1.60 eV)。晶面断裂能密度Sc计算表明，锆石晶体沿(200)面最易断裂，因此(200)面最易暴露。此外，Sc与表面能有良好相关性，在一定条件下，晶面断裂能密度Sc可用于快速评价晶面稳定性和反应性。
关键字: 锆石；晶面断裂能密度；断裂键密度；表面反应性
（Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:Exploring the mechanism of crystal fracture and crystal plane exposure is important for accurately controlling the surface properties of minerals. The fracture mechanism of mineral crystals with one type of fracture bond can be accurately analyzed by the surface fracture bond density Db method proposed by the author earlier. However, for crystals with two or more types of broken bonds, new methods need to be explored. Taking zircon crystal with two types of fracture bonds as an example, this paper proposes a method of crystal plane fracture energy (Sc) based on bond order weight by using first principles calculation and Bader charge analysis, which can quickly evaluate the degree of fracture difficulty of zircon along each facet and reveal the rules of surface exposure. The calculation and analysis of crystal chemical bond energy show that the size of chemical bond energy in zircon crystal is Si—O (6.00 eV)＞Zr—Oα (2.87 eV)＞Zr—Oβ (1.60 eV). The calculation of fracture energy shows that zircon crystals are most easily fractured along the (200) plane, so the (200) plane is the most easily exposed. In addition, we found a good correlation between the Sc and the surface energy, and the crystal plane fracture energy can be used to quickly evaluate the stability and reactivity of the facet under certain conditions.
Key words: zircon; crystal plane fracture energy; broken bonds density; surface reactivity
