Abstract
In this research, the efficiency of magnetic separation methods for processing of a low-grade iron pigments ore (red ochre) has been studied. Based on the mineralogical analyses (XRD), thin section and polish studies, the reserve is an iron sedimentary deposit with an average Fe grade of %31.3. The most valuable minerals are Hematite and Goethite and main gangue minerals are Calcite and Quartz. Wet and dry high-intensity magnetic separation methods were applied for processing. The full factorial design was implemented for all of the wet high-intensity magnetic separation (WHIMS) experiments. Factors of magnetic field intensity, rotor speed and feed water flowrate were considered for design. In optimal conditions in rougher stage, WHIMS produced a concentrate with grade %42.92 Fe and recovery %62.23 in magnetic field intensity 1.7 Tesla, feed water flowrate 5 liter per minute and speed of rotor 3 rounds per minute; also after two stage cleaning WHIMS produced a concentrate with Fe grade and Fe recovery of %56.12 and %38.56, respectively. The results of the dry high-intensity magnetic separation for the two coarser fractions showed that size fraction of coarser than 1000 micron produced a concentrate with Fe grade %40.32 and relative Fe recovery %95.11 and size fraction of -1000+150 micron with Fe grade %45. 04 and relative Fe recovery %75.14. The results of experiments show that there is a low capability for improving quality and grade of this ore. Achieved concentrate from experiments could be used as an initial feed of producing pigment.
Highlights
Red ochre is one of the most important iron oxide forms
Mineralogical analyses, thin section and polish studies have specified that the deposit is a kind of low-grade iron pigment containing Fe grade 31% and earthy Hematite is main iron mineral
Rougher stage of wet high-intensity magnetic separation (WHIMS) experiments was completed using full factorial design and field intensity, feed water flowrate and speed of drum were the effective factors on separator performance
Summary
Red ochre is one of the most important iron oxide forms. The main mineral of red ochre is Hematite (Fe2O3) and it uses in many industries such as paint, cement, chemical, cosmetics, plastic, paper, glass, ceramic and etc. [1,2]. There are many red ochre reserves in Iran which are mainly located in southern and central parts [3]. The majority of these deposits has a low grade and they should be processed to use in various industries [3,4]. Different separation methods such as Gravity, magnetic, flotation are mainly used for processing of these kinds of deposits [5,6,7,8,9]. In this research dry and wet high-intensity magnetic separation methods were applied in processing of red ochre
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