The effect of shungite pretreatment on quantitative extraction of metals

Abstract

One of the most interesting natural materials with a rich composition of various elements, including rare earth elements, is shungite. Inductively coupled plasma mass spectrometry (ICP-MS) was successfully used to detect metals in various ores, which has high sensitivity for determining elements even in trace amounts. ICP-MS analysis revealed 53 elements in shungite, the total content of which in the original sample did not exceed 3 wt%. The effect of preliminary treatment with various solvents (extraction) on the isolation and determination of the maximum content of elements in shungite was considered. The effect of parameters such as the nature of the extractant, sample mass, extraction time, and preliminary heat treatment on the total content of elements in the original shungite sample was studied. It was found that extraction with water, methanol, potassium hydroxide, or hydrochloric acid significantly increased the total detected content of elements in shungite; the total content of elements can reach 20 wt%. Data analysis showed that the detectable content of elements in a 0.2 g sample was higher than in a 0.5 g sample, and an increase in extraction time led to an increase in the detectable amounts of metals. Recommendations were given on sample preparation to achieve effective extraction and determination of metals by the ICP-MS method. The most comprehensive information on the content of elements in shungite can be obtained by extracting the sample with methanol.