Table 3-9 Comparison of Element Content in Coal from Other Mining Areas with Average Content in Relevant Range (wB/ 10-6)
sequential
Note: China and the world coal are based on Zhao Fenghua (1997), * elements are based on Zhao et al. (2002), and crustal abundance is based on et al. (1984).
Firstly, compared with the average content of elements in China and the world coal, the contents of La, Yb, Lu, U, As, Sb, K, Se, Sc, Cr, Fe, Sm, Eu, Tb, Yb, Lu and Br in Lilan coal are obviously higher. Thorium, tantalum, cobalt and bromine in Li Lan coal and arsenic, antimony, sodium, barium, selenium, rubidium, scandium, chromium, cobalt and zinc in Feicheng coal are obviously low. The average contents of cerium, neodymium, samarium, europium, terbium and sodium in Li Lan coal and lanthanum, cerium, neodymium, uranium, potassium and iron in Feicheng coal are higher than the world level, but lower than those in China coal. However, the average content of barium and rubidium in Lilan coal is lower than that in the world coal and higher than that in China coal.
Secondly, compared with the average contents of elements in the crust, the average contents of La, Ce, U, As, Sb, Se, Co, W, Ga and Mo in Li Lan coal and Eu, Tb, Lu, U, As, Sb, Se, Br and Mo in Feicheng coal are obviously higher. The average contents of nd, Sm, Eu, Tb, Yb, Lu, Na, K, Ba, Rb, Th, Cr, Hf, Cs, Sc, Fe, Ta, Br and La, Ce, Nd, Sm, Yb, Na, K, Ba, Rb, Th and Cr in Feicheng coal are obviously low.
Thirdly, by comparing the roof and floor, it can be known that the top and bottom elements of Lilan Mine are Tb, Yb, Lu, As, K, Rb, Cr, Hf, Cs, Sc, Fe, Ta, Co, Br, W, Ga and Mo, while the top and bottom elements of Yangzhuang Mine are La, Ce, nd, Sm, Eu and U.
Using the formula of enrichment coefficient (EF) proposed by Valkovic( 1983), the enrichment coefficients of 29 elements such As As in Li Lan coal and Feicheng coal (Table 3-9) and their frequency distribution (Figure 3- 17) are calculated. This book takes EF≥5 as the boundary of element enrichment and EF≤0.50 as the boundary of element dispersion. It is found that the dispersion and enrichment characteristics of 29 elements such as arsenic in Li Lan coal and Feicheng coal are as follows:
Figure 3- 17 Frequency Distribution of Element Enrichment Coefficient
The enrichment coefficient of 6.9%(2 kinds) elements in Lilan Mine is less than 0.5, and the enrichment coefficient of 17.24%(5 kinds) elements is greater than 5.0, that is, five elements As, U, Mo, Se and Sb are obviously enriched in coal, and the enrichment coefficients are 5 1.48 and 57.92 respectively. The enrichment coefficient of 17.24%(5 species) is between 0.5 ~ 1, that of 34.48%( 10 species) is between 1 ~ 2, and that of the other 7 elements is between 2 ~ 4. The enrichment coefficient of elements in Feicheng Mine is 13.79%(4 species) ≤0.5, and the enrichment coefficient of elements greater than 5.0 is 37.93%( 1 1 species), which is obviously larger than that in Lilan Mine. 1 1 The obviously enriched element is Sm. The enrichment coefficients are 9.77, 9.47, 13.95, 6.98, 19.74, 13.22, 8. 19, 22. 16, 26/kloc respectively.
From the content of trace elements in coal, Lilan Mine is rich in As, U, Mo, Se and Sb, with a few elements (6.9%) dispersed in coal, and most elements in coal are at a normal level. Feicheng Mine is rich in Sm, Eu, Tb, Yb, Lu, U, As, Sb, Se, Br, Mo, and a few elements (13.79%) are dispersed in coal, while the contents of other elements are at a normal level. The toxic elements listed In the handbook of toxic chemicals in the United States are As, Se, u, Mo, Sb, Br, Be, b, Co, Cd, Cl, Cu, f, Hf, in, Pb, Mn, Hg, ni, Ag, Sn, v, Zn, Ba, th, Tl and y, showing two. As and Sb are carcinogenic elements, U is radioactive, Se is toxic and Br is corrosive. These elements are easy to cause environmental pollution in the two mining areas. Bio-poisoning and environmental pollution caused by potentially toxic elements in coal have occurred in many countries around the world, such as North Carolina and Texas. Selenium produced by coal combustion leads to large-scale fish deaths. In the high selenium area of Enshi, Hubei, China, people and animals were poisoned by selenium because residents widely used high selenium stone coal as fuel. Arsenic discharged from coal-fired power plants in former Czechoslovakia delayed the growth of children's bones nearby, and more than 3,000 cases of arsenic poisoning were caused by the use of high arsenic coal in Guizhou, China. Therefore, from the perspective of environmental protection, the utilization of coal in these two mining areas should be deeply studied, and the environmental pollution caused by its combustion should be paid enough attention.