TN1161 : Preprocessing the Jajarm low grade bauxite to remove the silica and iron and to increase the capacity of Alumina production line
Thesis > Central Library of Shahrood University > Mining, Petroleum & Geophysics Engineering > MSc > 2023
Authors:
Amir Hossein Ashrafi [Author], Asghar Azizi[Supervisor], [Supervisor]
Abstarct: Aluminum is one of the most significant and plentiful mextallic elements in the earth's crust and is widely applied in various industrial fields owing to the high electrical and thermal conductivity attributes, high strength and hardness, good corrosion resistance, lightweight, and mechanical particularities. The primary resource for extracting aluminum is bauxite, and above 90% of the world's aluminum is obtained from bauxite. The global growth of aluminum demand with the modernization of our society has led to the interest in developing methods to produce aluminum from non-bauxite and low-grade resources. Bauxite with Al2O3 grade less than 50% is classified as low-grade bauxite due to the presence of impurities such as silica and iron oxide. Low-grade bauxites, in case of no preprocessing and the remaining of these impurities in the input load, the issues such as reduced recovery of the target mineral, diminished plant capacity, increased red mud production, and elevated energy consumption in the Bayer process will occur. Thus, in this study, the feasibility of removing these impurities from the bauxite using the different magnetic and flotation methods was investigated on the representative sample with d80 of 106 µm. At the first step, the different magnetic methods were used to eliminate the iron impurities from the Bauxite, and the results indicated that the high-gradient magnetic separation with a magnetic field intensity of 18000 Gauss has the best performance in the reduction of iron. The efficiency of iron removal using this method was obtained 68.85%. In the second step, the reverse and direct flotation methods were applied to remove the silica content in the sample. The findings showed that the reverse flotation process using 750 g/t Armac C collector and 1200 g/t starch as the depressant and H40 g/t MIBC as the frother at pH of H11 has the best efficiency for the removal of silica from the bauxite. In this case, the efficiency of silica removal was 52.95%. Ultimately, the high-gradient magnetic separation with an intensity of 18000 gauss followed by reverse flotation process with Armac C collector under optimal conditions was implemented on the bauxite sample studied. baxsed on the XRF analysis of the final tailings obtained from the flotation process, the content of Fe2O3 and SiO2 was found to be 17.76 and 22.11%, respectively.
Keywords:
#Low-grade bauxite #Jajarm alumina #Iron and silica Impurity #Magnetic separation #Reverse flotation #Removal efficiency. Keeping place: Central Library of Shahrood University
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