高频热等离子体热解水氯镁石沉积高纯氧化镁薄膜

The high temperature pyrolysis process from salt lake brine to high purity MgO is high energy consumption, low pyrolysis efficiency and badly corroded exhaust. In this project, based on the features of high temperature, high heat content and high reaction ability, rf (radio-frequency) thermal plasma is used as an ultra-high temperature heat source to intensify the pyrolysis process of bischofite (MgCl2·6H2O) from salt lake brine. The influence of plasma temperature, plasma gas, reaction time, feeding rate and other factors on the pyrolysis process of bischofite is investigated. Connecting the diagnostics of plasma characteristics and the analysis of phase composition and purity, the high temperature pyrolysis technique of bischofite in the rf thermal plasma is revealed. High purity MgO thin film is deposited in situ in the rf thermal plasma pyrolysis system, the temperature of substrate, temperature field in the reactor and reactor structure on the deposition rate, particle size and distribution, compactness of thin film are discussed, the deposition mechanism of pyrolysis particle is revealed. Furthermore, MgO thin film deposited is used as buffer layer for epitaxial growth of ferroelectric materials, and the influence of MgO thin film on the epitaxial growth of ferroelectric materials is analysized deeply for the reasonable, effective, and high value utilization of deposited MgO thin film. These fundamental researches will provide scientific guidance for the high temperature pyrolysis process of salt lake brine, development ideas for the comprehensive utilization of salt lake resources, and will contribute to width the application of plasma technology.

盐湖卤水高温热解制备高纯氧化镁过程耗能低效、污染严重。基于热等离子体的高温、高焓以及高反应活性，本课题采用高频热等离子体为超高温热源来强化盐湖水氯镁石高温热解过程，考察等离子体温度、气氛、反应时间、加料速率等因素对水氯镁石高温热解过程的影响，结合对等离子体特性诊断和热解产物的相成份及纯度分析，揭示水氯镁石在等离子体中的高温热解规律；在高频热等离子体热解系统中原位沉积氧化镁薄膜，探讨沉积基板温度、反应器温度场、反应器结构等因素对薄膜沉积速率、薄膜颗粒的粒径大小和分布、薄膜致密性的影响，揭示热解颗粒在等离子体系统中沉积行为规律；在此基础上，进一步将氧化镁薄膜应用于铁电缓冲层的应用中，深入分析薄膜特性对铁电材料外延生长的影响规律，指导热解后沉积薄膜的合理、有效、高价值利用。这些基础研究将为盐湖卤水的高温热解过程提供科学指导，为盐湖资源的综合利用提供发展思路，并有利于拓宽等离子体技术的应用领域。

盐湖卤水高温热解制备高纯氧化镁过程耗能低效、污染严重。基于热等离子体的高温、高焓以及高反应活性，本课题采用高频热等离子体为超高温热源来强化盐湖水氯镁石高温热解过程，考察等离子体温度、气氛、反应时间、加料速率、加料方式等因素对水氯镁石高温热解过程的影响，结合OES光谱诊断和热解产物的相成份及纯度分析，揭示水氯镁石在等离子体中的高温热解规律；在高频热等离子体热解系统中原位沉积氧化镁薄膜，探讨沉积基板温度、基板晶面取向、反应器温度场、反应器结构等因素对薄膜沉积速率、薄膜颗粒的粒径大小和分布、薄膜致密性、薄膜表面形貌等的影响，揭示热解颗粒在等离子体系统中沉积行为规律；在此基础上考察所制备的薄膜样品的光致发光性能，探索氧化镁薄膜在光电器件领域的应用潜力, 指导热解后沉积薄膜的合理、有效、高价值利用。这些基础研究将为盐湖卤水的高温热解过程提供科学指导，为盐湖资源的综合利用提供发展思路，并有利于拓宽等离子体技术的应用领域。