河南某地粘土矿物新型传压介质研制及金刚石合成工业试验

Preparation of Pressure Transmitting Medium Composed of Clay Minerals Produced in Henan Province and Enlarged Scale Tests on Diamond Synthesis

河南某地粘土矿物具有优异的传压和密封性能,是传统金刚石合成用传压介质辅料叶蜡石的替代品。将该粘土矿物按照粗(-1.4 mm+0.5 mm)、中(-0.5 mm+0.25 mm)、细(-0.25 mm)三个粒级进行配比,重量比为4∶4∶2,并添加5%水玻璃作为粘结剂,混合均匀,作为密封材料。白云石按照粗(-0.18 mm+0.15 mm)、细(-0.15 mm)两个粒级进行配比,重量比为8∶2,添加8%水玻璃,混合均匀,作为传压材料。经粉压成型和焙烧热处理,制成传压层在内部,密封层在外部,外形尺寸为65 mm×65 mm×32.5 mm,内径为38.5 mm的分体型复合传压介质。经金刚石合成工业试验得出,金刚石产品单产量为116.0 ct,≥130 N颗粒含量为28.0%,≥40/60目颗粒含量为77.5%,单位锤耗为0.28 g。该新型传压介质的使用性能跟常规叶蜡石传压介质相当,合成出的金刚石产品两者之间没有明显差异。

Clay minerals produced in Henan procince,which have good sealing performance and pressure transmitting property,can take place of pyrophyllite in the use of pressure transmitting medium. The new pressure transmitting medium introduced in the paper was made by sealing layer and pressure transmitting layer together. The sealing layer was made by the clay minerals,which were divided into three size range（-1. 4 mm ＋ 0. 5 mm,-0. 5 mm ＋ 0. 25 mm and-0. 25 mm） and the weight proportion was 4：4：2.whereas the pressure transmitting layer was made by dolomite,which was divided into two size range（-0. 18 mm ＋ 0. 15 mm and-0. 15 mm） and the weight proportion was 8：2. In addition,adding 5% and 8% binder（ sodium silicate） to the sealing material and pressure transmitting material respectively. The two kinds of materials were molded by pressure,in which the sealing material was in the outside and pressure transmitting material was in the inside,and roasted at a certion temperature. The external sizes of the new medium were 65 mm × 65 mm × 32. 5 mm,and the size of internal cavity was 38. 5 mm. With the pressure transmitting medium,a large number of diamond synthesis tests were conducted. The tests results showed that the per unit yield of diamond was 116. 0 ct,the proportion of crystals whosecompression strength and grain size were more than 130 N and 40/60 mesh were 28. 0% and 77. 5%respectively,as well as the cemented carbide anvil consumption was less than 0. 28 g per 1 g of the produced diamond. The new medium made by clay minerals has the same effect as that made by pyrophyllite material on diamond synthesis.