Chemical composition of bauxite deposits in Henan province

Bauxite in Henan province has the characteristics of high aluminum, high silicon and low iron. The main chemical components are shown in Table 4.4.

Table 4.4 Chemical Composition wB/% of Bauxite in Henan Province

(According to Lv Xia 1985, 1996)

1)Al2O3: The mass fraction of Al2O3 in bauxite in Henan is generally 60%~70%, and the highest is 82.82%. Generally speaking, the mass fraction of Al2O3 in earthy and sandy ores is higher, often above 70%. The Al2O3 content of dense, oolitic and breccia ores is low. Especially, the Al2O3 mass fraction of dense ore is lower. Al2O3 in bauxite in Henan Province mainly occurs in diaspore. The more Shi Yue in hard water, the higher the Al2O3 content. Another part of Al2O3 exists in clay minerals such as kaolinite, illite, chlorite, montmorillonite and pyrophyllite, and only a small amount exists in gibbsite and boehmite.

2) SiO _ 2: The mass fraction of SiO _ 2 in bauxite in Henan Province is generally 5%~ 15%, with the highest being 22% and the lowest being 0.5%. Silica mainly exists in clay minerals such as kaolinite, illite, chlorite, montmorillonite and halloysite, with a small amount of feldspar, quartz and zircon.

3)Fe2O3: The mass fraction of Fe2O3 in bauxite in Henan is generally 2%~4%, the highest is 29. 19%, and the lowest is 0.5%. Iron mainly exists in the form of hematite and goethite, followed by siderite, pyrite and tantalite.

4) TiO _ 2: The general mass fraction of TiO _ 2 in bauxite in Henan is 2.5%~3.5%, the highest is 5.58%, and the lowest is 1.38%. The main minerals of titanium dioxide are anatase, rutile, titanium dioxide and a small amount of brookite.

5)K2O and Na2O: The mass fraction of K2O and Na2O in bauxite is generally less than 1%, and the mass fraction of K2O in some mining areas can be as high as 4.65%. K ions mainly occur in illite, followed by kaolinite, montmorillonite and other minerals.

6)S: The mass fraction of S in bauxite in Henan Province is generally less than 1%, and it can reach 13.44% in some cases, mainly occurring in pyrite.

7)CaO and MgO: The mass fraction of calcium and magnesium in bauxite is low, generally 0.2%~0.4%, and can reach 2.65% in some cases. They are mainly produced in calcite and dolomite.

Trace elements in bauxite in Henan, 4.3.2.2.

The trace elements in bauxite in Henan are generally phosphorus, vanadium, cerium, lithium, gallium, zirconium, strontium, barium, manganese, boron, chromium, nickel, copper, lead, thorium, uranium, niobium and tantalum. See Table 4.5 for trace elements in bauxite.

Table 4.5 Average Mass Fraction and Clark Value of Trace Elements in Bauxite in Henan Province

(According to the internal data of the Second Geological Survey Team of Henan Geological Bureau)

Correlation of Elements in Bauxite in 4.3.2.3

Cui Bo et al. (1980) calculated the element correlations of Al2O3, SiO2, Fe2O3, TiO2, CaO, MgO, K2O and Na2O in 260 bauxite samples, and the results are shown in Table 4.6. As can be seen from the table, Al2O3 has a positive correlation with TiO _ 2, with a correlation coefficient of 0. 193, while Al2O3 has a negative correlation with SiO _ 2, Fe2O3, CaO, MgO, K2O and Na2O, and has the best correlation with SiO _ 2, with a correlation coefficient of -0.926, indicating that lA and Si in the ore have a growth and decline relationship. With the increase of Al content, The correlation coefficients of Fe2O3 and K2O with Na2O and Al2O3 are -0.348, -0.3 19 and -0.648 respectively. Among these elements, except TiO2, the mass fraction of Al2O3 decreases with the increase of other elements, and vice versa.

Table 4.6 Correlation Matrix of Chemical Composition of Bauxite in Henan Province