人工合成金刚石半成品中清除非金刚石碳的新方法——滴酸法

A new method for the removal of non-diamond carbon in the semi-product of diamond synthesis——A droping acid method

在人工合成金刚石的半成品中,都含有相当数量的非金刚石碳。为了清除这些非金刚石碳,最常用的是若干种液相氧化法,但是存在有成本高,废料中含有可能污染环境的物质等缺点。建立了一种用硫酸和硝酸在常压下清除人工合成金刚石半成品中非金刚石碳的新方法—滴酸法。其做法是,将半成品与浓硫酸混合,加热到200℃以上,将浓硝酸缓慢滴入,进行氧化处理,这样可以使混合物保保持较高温度,从而提高了硝酸的氧化能力。经过多次试用,其操作时间和得到的结果,与以前使用的硫酸、硝酸加发烟硫酸的方法基本相同。此方法具有成本低和不产生危害环境的含金属污染物的优点。

The semi - products of synthetic diamond always contain a significant amount of non - diamond carbons. Liquid - phase oxidation methods, the most commonly used purification methods, have a number of shortcomings, such as high cost and the waste materials, which will pollute environment. A new method to remove the non - diamond carbons in the semi - product of synthetic diamond using only sulfuric acid and nitric acid under atmospheric pressure is developed, in which the semi - product is mixed with concentrated sulfuric acid and the mixture is heated to above 200~C, then concentrated nitric acid is added dropwise into the mixture. The temperature of the mixture can be kept at above 200~C, thus the oxidation power of nitric acid can be kept at a rather high level and the non -diamond carbon can be removed completely. This method has been used for many times and similar operation time and product are obtained as that using the treatment with a mixture of sulfuric acid, nitric acid and fuming sulfuric acid. This new method is rather cheap and does not produce any metal containing pollutants.