缅甸、越南红宝石的热处理研究  

Research on Heat Treatment of Ruby from Burma and Vietnam

作　　者：王文杰[1] 狄敬如[1] 

机构地区：[1]中国地质大学珠宝学院,湖北武汉430074

出　　处：《宝石和宝石学杂志》2014年第4期29-38,共10页Journal of Gems & Gemmology

摘　　要：对缅甸、越南带有蓝紫色调的天然红宝石样品进行了热处理改善工艺研究,采用激光诱导离解光谱仪(LIBS)和X射线荧光能谱仪(EDXRF)对样品进行定性和定量测试,结果显示,样品中含有Al、Fe、Cr、Ca、Mg、Ti、Si等元素,且随着红宝石紫色调的加深,Fe的质量分数增加。热处理实验中对加热温度、加热时间及速率、添加剂等适当调控,从而得出最佳实验方案;利用USB 4000对处理前、后的样品进行测试分析,结果显示在温度为1 580℃,氧化氛围,添加剂为硼酸钠和三氧化二铝的条件下的热处理工艺,能够很好地改变微量元素Fe,Ti的存在状态,减少由其产生的紫色调、蓝紫色调,使红色纯正。由于样品裂隙发育,即使有助熔剂充填,也并不能很好的改善其透明度,只是在裂隙中残留下白色物质。This research aimed to investigate the heat treatment changing the colour and clarity of natural rubies from Burma and Vietnam. The samples are rosy with purple and bluish violet hue and have much fracture. To support experiment with the preparation, the natural rubies were analyzed by LIBS and EDXRF to get the main elements and the colour causing elements. It shows that there are A1, Fe, Cr, Ca, Mg, Ti and Si and the purple and bluish violet is caused by Fe and Ti ions. It is known that the Cr^3＋ is responsible for the red colour of ruby and the d—d transition of Cr^3＋ leads to absorption band at 410 and 540 nm and absorption line at 692 nm. The bluish violet colour in ruby is the result of intervalence charge transfer between Fe^2＋ and Ti^4＋ ions and it causes absorption at 564 nm. In nature, Fe presents as Fe^3＋ ions and substitutes A1^3＋ , giving a slight yellow colour in the ruby. However, it affects little the red colour of the ruby. The heat treatment was divided into two parts according to the temperature setting and components of fluxing agent. One is in an oxidizing atmosphere with the fluxing agent of sodium borate at temperature of 1 500 ℃ and 1 580 ℃. After each heat treatment, USB 4000was employed to measure the absorption spectrum. The results suggested that after heat treatment, the colour of samples changed from deep purple red to slight purple red, but the change is not much obvious. In additional, when the temperature was setting at 1 500 ℃, there was some white substance on the surface of samples. And the white substance entered into the fractures when the temperature was setting at 1 580 ℃. The element of white substance was tested to be Na. It illustrated that the temperature of 1 580 ℃ contributed to the fluxing agent diffusion into the ruby. The absorption caused by Cr^3＋ according to the result of USB 4000 was enhanced, which can illustrate that after heat treatment the bluish violet hue diminished. The other part of the heat treatment was also setting in an oxi

关 键 词：红宝石 热处理 USB 4000 缅甸 越南 

分 类 号：TS93[轻工技术与工程]