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Effect of blunging process on purification of halloysite ore from ferrous impurities by dry magnetic separation

Durgut Emrah, Çınar Mustafa, Boylu Feridun, Ozdemir Orhan

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 2

art. no. 187186

EN

The objective of this research is to study the effects of feed particle size, splitter angle, and washing process on Fe2O3 removal efficiency in the separation of ferrous impurities from halloysite ore by dry magnetic separation in order to increase the purity of halloysite sample after crushing and blunging processes separately. Firstly, after crushing ore in a jaw crusher and sizing to -2+1 mm, -1+0.5 mm, and -0.5+0.212 mm fractions, the sized materials were fed to REMS-type dry magnetic separator at a constant belt speed of 300 rpm with the splitter angles of 0, 15, 30º separately. Maximum Fe2O3 removal efficiency (FRE) (97.1%) was obtained in the nonmagnetic product at -0.5+0.212 mm size fraction and 0º splitter angle. The minimum Fe2O3 content (1.3%) was reached in the nonmagnetic product obtained in the experiment with the feed size of -2+1 mm and a splitter angle of 0º. Secondly, dry magnetic separation was applied to the washed -2+0.212 mm size fraction after drying at room temperature to evaluate the coarse particle-sized halloysite ore that was gained by mechanical dispersion in the aqueous medium towards sodium hexametaphosphate (SHMP), while a significant part of the clay minerals went into fine size after the dispersion process. In the experiment performed with a 0º splitter angle after washing, it was determined that halloysite concentrate of 0.4% Fe2O3 content could be obtained with 98.8% Fe2O3 removal efficiency. As a result of dry magnetic separation experiments, it was seen that Fe2O3 removal efficiency decreased as the splitter angle increased, while Fe2O3 content in magnetic and nonmagnetic products increased. It was determined that washing and cleaning of finesized minerals plastered on particle surfaces after mechanical dispersion and particle release of minerals with different magnetic properties increased the dry magnetic separation efficiency, and nonmagnetic products with very low Fe2O3 (0.4%) and high Al2O3 (31.9%) content was obtained. The blunging process in the presence of dispersant caused the dispersion of clay minerals and allowed to liberating of the ferrous minerals from the halloysite ore, hence the increase in the FRE for the magnetic separation.

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Effect of crystallinity and surface silanol groups on rheological properties of different sepiolites

Çınar Mustafa, Gülgönül Ilhan, Ozdemir Orhan, Çelik Mehmet S.

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 153947

EN

In this study, differences in the rheological properties of three different types of brown sepiolites (K1, K2, and K3) along with one beige (B) sepiolite with different physicochemical properties were explained based on their crystallinity and level of surface silanol groups. Towards this aim, SEM images, XRD and chemical analyses, cation exchange capacity (CEC), and water absorption tests were conducted along with surface area measurements and time-dependent pH profiles. The pH profiles at 3% by wt. revealed that each sepiolite sample attained the equilibrium at different times. These differences showed a parallel behavior with the degree of crystallinity. While sepiolite with better crystallinity (K1) was rather slow in reaching the equilibrium pH, the sepiolites with poor crystallinity (B and K3) reached their equilibrium pH more quickly. The rheological studies conducted with different sepiolites at 3% solids concentration exhibited time-dependent flow of the Bingham plastic model and thixotropic. Differences observed in the rheological behavior of sepiolites were found to correlate with the fiber size, CEC, surface area, and water absorption. The results further indicated that sepiolites with low crystallinity or high level of surface silanol groups (K3 and B sepiolites) show the best rheological properties.

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Mineral beneficiation of nepheline syenite with combination of dry magnetic separation and flotation methods

Çınar Mustafa, Durgut Emrah

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 5

1227--1238

EN

Nepheline syenite is an important raw material for ceramic body composition as a melting agent. However, impurities such as iron, titanium, mica, and calcite minerals in nepheline syenite can lead to quality problems on the surface of floor tile because of different sintering properties. Therefore, these impurities should be eliminated from syenite before sintering process to increase its quality while reducing economic and environmental impacts. In this study, it was aimed to reduce impurities of nepheline syenite using dry magnetic separation and flotation methods. The dry magnetic separation results showed that the amount of TiO2+Fe2O3 in the sample decreased from 2.50% to 0.06%. In additio to this, optimum flotation conditions were determined while separating calcite, mica, and further iron bearing minerals from the nepheline syenite by using sequential flotation method. The optimum flotation conditions for calcite flotation were determined as natural pH: 7.9 and 500 g/Mg DER NA7 collector dosage; for mica removal pH: 3.1 and 500 g/Mg Custamine 9024 or A4 collector dosage. After overall mineral beneficiation experiments, albite+microcline mineral content increased from 78% to 97%. In conclusion, a clean concentrate for ceramic body and frit composition quality was gained from nepheline syenite containing high amount of Fe2O3 and TiO2 with dry magnetic separation and flotation experiments.