Abstract
Iron-bearing minerals are the most important interfering compounds that are found with bauxite reserves. The element iron has adverse effects on bauxite applications, including the use of bauxite in refractory soils. The purpose of this research is to investigate the possibility of iron removal from low-grade bauxite ores to utilize them in refractory industries. For achieving this purpose, iron removal tests were performed on bauxite samples with an alumina to silica modulus of 0.73. After determining the appropriate iron removal method among the magnetic separation, calcination, and leaching (with H2SO4 and HCl) processes, optimal separation conditions were determined by tests that were designed using the Taguchi method. According to leaching results, using HCl for raw feed (un-calcined) provided the best result for iron removal. During this test, Fe2O3 grade decreased from 5.14% to 0.08%, and the alumina to silica modulus increased to 0.75. Calcination of the concentrate obtained from this test has led to favorable results in reducing the Fe2O3 grade (0.04%) and increasing the Al2O3 grade. Afterwards, in tests designed by the Taguchi method, the effect of parameters such as time, process temperature, HCl concentration, and feed grain size on iron removal from bauxite by HCl leaching processes are discussed. According to the results, the best efficiency of iron removal for a feed grain size of 250 µm is achieved in the following conditions: 30% HCl, process temperature of 25°C, and process time of 120 minutes. In this case, iron removal efficiency and Fe2O3 grade in process concentrate are 92.78% and 0.56%, respectively.
Highlights
Bauxite ores are materials left over from the degradation and erosion of primary rocks such as granite, basalt, and nepheline syenite, or clay minerals
Afterwards, in tests designed by the Taguchi method, the effect of parameters such as time, process temperature, HCl concentration, and feed grain size on iron removal from bauxite by HCl leaching processes are discussed
Leaching tests using HCl and H2SO4 acids were performed on the studied low-grade bauxite samples to reduce the amount of iron content to the permissible stand
Summary
Bauxite ores are materials left over from the degradation and erosion of primary rocks such as granite, basalt, and nepheline syenite, or clay minerals. Bauxite reserves contain high amounts of aluminum and are one of the most important aluminum ores (Donaldson and Raahauge, 2017). More than 100 minerals have been identified for bauxites, of which only a few, including gibbsite Al(OH), boehmite (γ-AlO(OH)), and diaspore (α-AlO(OH)) are important reserves of aluminum (Pereira et al, 2019). In each case, depending on the type of application of bauxite, the standard and its chemical composition are varied. Bauxites used in the metal industry contain a high amount
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
