Experimental Conditions for Zn-Fe Reduction Method of ¹⁴C Graphite Preparation

As a vital sample preparation method for ¹⁴C graphite, the Zn-Fe reduction method has been widely used in various laboratories. However, there is still insufficient to improve the efficiency of graphite synthesis and reduce modern carbon pollution and other conditions test methodology. In this work, ¹⁴C graphite samples were prepared based on the Zn-Fe reduction method, and the experimented key parameters such as the reduction reaction temperature, reaction time, reagent dosage, Fe powder precleaned, and other factors were investigated and determined. For ¹⁴C graphite sample(≈1 mg), the amount of Zn is between 18~22 mg, and the amount of Fe is between 2.5~3.0 mg. Fe is precleaned by heating to 400 °C for 3h under air environment, and the reduction process is treated by heating at 650 °C for 8 h in a condensing graphite reduction furnace. Compared with background samples (commercial graphite) and standard samples (OX-II, IECA-C8, CSC) the results showed that the performance under this condition is better than before. It provides a basis for optimizing the ¹⁴C graphite preparation method, and lays a foundation for reducing the background level of trace ¹⁴C graphite prepared by Zn-Fe reduction method.