Optimization of the conditions for leaching-out of mercury from coal with strain Aspergillus flavus M-3

Mercury is one of the toxic metallic elements in coal. How to remove it from coal remains a knotty problem in the research work on clean and high-efficiency utilization of coal. In order to explore the optimal conditions for extraction of mercury from coal, the mercury-rich coal produced from Laoyingshan Coal Mine in Guizhou Province is taken as the object to explore by using the response surface method the influential factors involved in mercury extraction process with the use of M-3-a kind of strain identified by molecular biology as Aspergillus flavus M-3 which is separated from the soil in the local area and can produce the intended mercury leaching effect. It is aimed to determine revealed by test results, the amount of coal added, dosage of surfactant and dose of innoculation are the main factors influencing the mercury extraction effect; and when the coal is added at an amount of 3 g with a dosage of surfactant of 1 mL and an innoculation dose of 10%, a best mercury extraction effect with a mercury extraction rate up to 84.89% can be obtained. It is suggests that there exists a certain feasibility to remove mercury from coal using bioleaching method. The test results may provide a technical support for clean and high-efficiency utilization of coal.