Measuring the carbon and sulfur content in lead samples using an elemental analyzer

With the development of modern science, the quantitative analysis of non-metallic elements is becoming more and more important. The quantitative analysis of non-metallic elements such as C, S, and Cl is particularly necessary in geological surveys, chemical prospecting, environmental protection, hydrogeology, chemical industry, agriculture, pharmaceuticals, coal, thermal power plants, and biochemistry and other research and daily analysis. For example, in the full analysis of rocks and minerals in the geological field, C, S, and Cl are must-measure elements. However, the previous analytical technology required more than two instruments to complete the determination of the above three elements. The multi EA?000 element analyzer launched by Analytik Jena AG in Germany in recent years can complete the determination of the three elements of C, S, and Cl on one instrument. This article introduces the method of using this instrument to measure the carbon and sulfur content in lead-containing samples. The analysis is very simple and fast.
The multi EA2000 element analyzer is a new, high-end element analyzer designed specifically for analyzing the total carbon, total sulfur, and total chlorine content in solid samples and slurry samples. It is also a solid sample TOC analyzer.

Instrument Principle

The multi EA2000 elemental analyzer uses high temperature oxidation to completely decompose the sample, decomposing all carbon-containing compounds into carbon dioxide, and all sulfur-containing compounds into sulfur dioxide, which are measured by NDIR non-dispersive infrared detectors; chlorine-containing compounds are decomposed into HCl and measured by microcoulometric electrochemical detectors.

It is a very simple method to measure the content of carbon and sulfur elements in lead-containing samples by high temperature combustion. In the detection of lead-containing samples, high lead content will have a certain impact on the determination of sulfur. The following description is a solution to this problem.

测量过程

所有的样品都是粉末状的，根据不同的碳硫的含量，称取50～500mg样品置于陶瓷舟中，添加适量添加剂，在1450℃的条件下，在multi EA 2000 C/S分析仪上进行操作，每个单一样品进行十次分析。

■ 典型的含铅样品

典型的含铅样品包括锌和铅制品的灰尘和矿渣，和铅蓄电池回收中的铅糊，碎片。

样品中铅含量很高时，分析样品时问题会很显著地存在。氧化铅在高温下升华并且堆积在燃烧管内和气体管路当中乃致颗粒过滤器，它部分地吸收分析气体导致测量结果偏低并且不具有重复性。而且，氧化铅会导致分析仪的污染。为了解决这个问题，在含铅样品中检测碳硫必须找到适当的添加剂。
■ 使用添加剂

在燃烧分析当中，加入到样品中的添加物质被用来影响反应温度，减弱燃烧反应，补偿基体影响或者使含有难燃烧化合物的样品完全氧化。典型的添加剂如：FePO4，锡，石英砂，五氧化二钒等。

高铅含量的样品在检测过程中会存在很大的问题，导致测量结果偏低。锡和石英绵的加入对分析过程和测量结果没有任何影响，但当使用五氧化二钒做为添加剂时，硫的检测得到了预期的测量结果和重复性。

结论

在高温燃烧系统中（最佳温度：1450℃），加入添加剂使硫含量的测量呈上升的趋势，重复性的结果仅仅是通过选择合适的添加剂就可以实现。当添加强氧化剂V2O5的时候，和加入其它的各种添加剂相比较，在硫的检测中硫含量的波动就非常小。用这种方法，即使是铅含量非常高的样品也能用高温燃烧的方法很容易并且快速地检测出来。