Chemical Forms And Leaching Experiment Of Heavy Metals In Coal Gangue

The coal resource is extremely rich in Shanxi Province and the coal reserve is in the forefront of the country. It brings economic benefits as well as tremendous impact on the environment and people's lives. In the process of coal production, there is a large amount of solid waste-coal gangue. Due to low utilization, a large number of heavy metals in the coal gangues accumulated in the earth's surface will be released through a series of external forces, such as efflorescence, rainfall leaching and so on. Thus, it can bring pollution to the local soil and water environment.In this paper, heavy metals of five coal mines in Shanxi were comparative analysed and evaluated.One of the coal mines was leached in the laboratory under natural conditions to study some of the factors and orderliness affecting the precipitation of heavy metals. And have studied the chemical forms of coal gangue and it's ash burned in a high-temperature. The major contents are summarized as follows:Chapterâ… :Shanxi is known as a coal production base, but it also brings a lot of solid waste-coal gangue and pollution to the environment. In this chapter, the production and composition of the coal gangue, the effect and damage on the environment, pollution of heavy metals were reviewed.Chapterâ…¡:In this chapter, the coal gangues of five coal mines in Gujiao, Jin cheng, Yangquan, Datong and Pingshuo were analyzed. The contents of trace elements in these coal gangues were measured and were compared.The possible harm to the soil was also evaluated.Chapterâ…¢:In this chapter analyzes the chemical forms of six heavy metals in coal gangue and its ash, most elements are in the form of silicate fraction and Oxidable fraction which is very stable,the reductive fraction which is kind of stable is secondary.After the coal gangue burning into ash by high temperature, most of the elements which include the most active exchangeable fraction and the carbonate fraction which can be extracted by weak acid will be decreased, the content of silicate fraction will increased and reduce environmental impact,except the element Cr.Chapterâ…£:In this chapter, the coal gangues of Gujiao were analyzed and simulated leaching in the laboratory. The leaching time, acidity, temperature, and leaching times were studied for the effect on the precipitation of heavy metals. The precipitation of heavy metals in the leaching was determined by the existent state in the coal gangues. Most of the heavy metals were stably precipitated within 24 hours and the precipitation concentration was related to the pH value.