沉积岩中有机碳的测定

引言在沉积岩的形成和变化过程中,特别是在成岩过程中,有机质在促进各种元素的迁移、富集和使它们从一种矿物转变为另一种矿物上,有着很大的作用。近年来,有机地球化学的研究,不仅在可燃性有机岩方面有很大的进展,而且在沉积非金属和金属矿床,特别是在稀有分散元素和放射性元素矿床的研究中,也得到了极大的重视和发展。在一般沉积岩中常或多或少的含有有机质,但目前还没有直接测定其总含量的简便完善的方法。由于碳是有机质的主要组成元素,因此普通采用岩石中的有机碳含量作为有机质总含量的标志。由于工作的需要,我们对测定有机碳的湿烧法进行了试验研究,并在测定方法上作了一些改进。现将该方法报导如下,请批评指正。

THE DETERMINATION OF ORGANIC CARBON IN SEDIMENTARY ROCKS

The "wet combustio" method for determining the organic carbon in sedimentary rocks is simple and reliable.The free carbonate in rocks may be removed by acid pre- treatment,and the pyrite will not do harm to the determination.The organic carbonic carbonaceous rocks cannot be oxidized completely unless the phosphoric acid must be added to the oxidation mixture,in which the concentration of sulphuric acid must have the acid-water ratio of 3:2(V/V).By this method seven to eight samples may be done a day.The results are as good as those obtained by the "dry combustion" method. But the rapid titration method of tyurin’s cannot be used to determine the organic carbon in sedimentary rocks,because the results obtained by this method are often high due to pyrite in the samples,and again,sometimes the results are low due to incomplete oxidation of the carbon.