Migration and enrichment of arsenic during coal washing

Abstract

During the processing and utilization of coal resources, some heavy metal elements will be enriched in the environment, which is harmful to the environment and the human body.In this study, low-ash, high-sulfur coal samples and high-ash, low-sulfur coal samples from Inner Mongolia were selected for float-and-sink test and flotation, and were analyzed by inductively coupled plasma mass spectrometer (ICP-MS), X-ray diffraction analysis, X-ray fluorescence analysis, and scanning electron microscopy energy spectrum analysis.Infrared spectroscopy and other test methods were used to study the occurrence form of heavy metal arsenic in coal and its migration and enrichment law during the processing.The experimental results show that the two coal samples demonstrates the highest proportion of arsenic present in the aluminosilicate bound state, reaching more than 50 %, but the types of aluminosilicate minerals are not the same, and the occurrence of arsenic has obvious differences.Flotation results show that arsenic in low-ash and high-sulfur coal sample is mainly associated with minerals and concentrated in the denser part, while high-ash and low-sulfur coal is mainly concentrated in the part with lower density and higher organic content; there are also differences in the migration law of arsenic in flotation.During the flotation, the arsenic in low-ash and high-sulfur coal migrates to the tailings, while the arsenic in the high-ash and low-sulfur coal migrates to the clean coal.The above findings show that it is feasible to remove arsenic from low-ash and high-sulfur coal sample by flotation but the effect is not so good for high-ash and low-sulfur coal sample, indicating that the removal of arsenic must consider the impact of coal type.

Keywords

• inner mongolia coal
• heavy metal elements
• float-and-sink test
• flotation
• migration and enrichment