合成金刚石生产中叶蜡石传压密封材料矿物学研究

叶蜡石是高温高压合成金刚石的关键辅助材料。叶蜡石传压密封材料的性能主要取决于叶蜡石矿石的矿物组成。叶蜡石矿石中的杂质矿物主要是一水硬铝石、明矾石、长石、高岭石、绢云母、绿泥石、石英、赤铁矿、钛铁矿、褐铁矿、金红石等。具有层状结构的矿物－水硬铝石、高岭石、绢云母、绿泥石等总量不超过10％，不会影响制品的传压性能。明矾石在高温高压下不稳定，是有害组分。长石、石英等非层状结构的矿物含量高时，会使叶蜡石传压密封材料静压流变特性变差，对传压性能是有害组分，应控制在小于5％，非常纯净的叶蜡石矿石制成的粉压块传压性能良好，但内摩擦系数小，密封性能差，常发生高压挤出和顶锤破坏现象，少量的赤铁矿、钛铁矿、褐铁矿、金红石矿物存在可以提高密封性能。

MINERALOGICAL RESEARCH ON PYROPHILLITE-A PRESSURE-TRANSFER AND SEALING MATERIAL IN PRODUCTION OF SYNTHETIC DIAMOND

Pyrophyllite is a key assistant material in production of synthetic diamond. Capability of pressure-transferring and sealing relies on the mineral composition of pyrophyllite ore. Impurity minerals are diaspore, alunite, feldspar, kaolinite, sericite, chlorite, quartz, hematite, ilmenite, limonite and rutile in pyrophyllite ore. If the mineral sum of diaspore, kaolinite, sericite and chlorite which are sandwich is not more than 10%, the capability of pressure-passing and sealing of the products is not affected. Alunite is instable at high temperature and pressure. Feldspar and quartz are non-sandwich minerals. When more than 5%, the flowing transmutation speciality of pyrophyllite material passing pressure and sealing becomes worse. Materials passing pressure and sealing made-up by the ore of pure pyrophyllite is good in capability of passing pressure and bad in capability of sealing. If there are little hematite, ilmenite, limonite and rutile in pyrophyllite ore, the capability of sealing becomes good.