USE OF HIGH GRADIENT MAGNETIC SEPARATION IN DETAILED CLAY MINERAL STUDIES

1988 ◽  
Vol 68 (3) ◽  
pp. 645-655 ◽  
Author(s):  
S. K. GHABRU ◽  
R. J. ST. ARNAUD ◽  
A. R. MERMUT
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Separation ◽  
Mixed Layer ◽  
Clay Mineralogy ◽  
Magnetic Flux Density ◽  
High Gradient Magnetic Separation ◽  
High Gradient ◽  
The Stability ◽  
Iron Bearing

High gradient magnetic separation is a simple, inexpensive, nondestructive and rapid means of concentrating iron-bearing minerals to nearly monomineralic levels, particularly those present in undetectable proportions in soil clays. The use of variable magnetic flux density further allows subfractionation of the iron-bearing minerals. Besides iron content, the efficiency of high gradient magnetic separation is highly dependent on the particle size. The stability of suspension, suitable flow rates, contact time and the packing of steel wool are significant factors. The experimental setup used in this study was effective for 2–0.2 μm clays but modifications are necessary to adapt the technique to finer (< 0.2 μm) particle sizes. This resulted in the separation of three distinct mineral groups: (a) smectite, kaolinite, quartz and feldspars, which were entirely associated with the > 1.38 Tesla (T) fraction, suggesting that the smectite and kaolinite present in these soils contain little or no iron; (b) vermiculite, mixed-layer minerals and mica, which were present in all the high gradient magnetic separation fractions; and (c) amphiboles and hydroxy interlayered minerals concentrated only in the < 1.38 T fractions. The contents of hydroxy interlayered minerals and amphiboles increased with decreasing levels of magnetic flux density and concentrated in the < 0.20 T fraction, from which they were further separated into monomineralic separates. A very small proportion of the interlayered mineral present in the total clay had a non-iron-bearing (probably Al-Mg interlayered) counterpart. The iron-bearing vermiculite, mixed-layer minerals (weathering products of biotite) and mica showed different iron contents. Key words: Magnetic separation, iron-bearing minerals, clay mineralogy, X-ray diffraction, scanning electron microscopy

LIQUID MAGNETIC SEPARATION OF IRON-BEARING MINERALS FROM SAND FRACTIONS OF SOILS

1987 ◽  
Vol 67 (3) ◽  
pp. 561-569 ◽  
Author(s):  
S. K. GHABRU ◽  
R. J. St. ARNAUD ◽  
A. R. MERMUT
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Separation ◽  
Effective Means ◽  
Soil Samples ◽  
Magnetic Flux Density ◽  
Solid Solution Series ◽  
Ultrasonic Dispersion ◽  
Untreated Soil ◽  
Iron Bearing

The study provides a new liquid magnetic separation (LMS) technique for concentrating sand-sized iron-bearing minerals, in general, and for quantitative isolation of biotite, in particular, from soils. Sand fractions (100–250 μm), separated from untreated soil samples from a Gray Luvisol from Saskatchewan by ultrasonic dispersion and sieving, were processed by LMS at various levels of magnetic flux density. The LMS separates obtained at increasing level of magnetic flux density showed a decreasing iron content. A linear relationship was observed between the two variables within the range of 2.5–28.0% Fe2O3 and 0.15–0.92 Tesla (T) magnetic flux density with a correlation value of R = 0.99. Mineral grains with as low as 1.09% Fe2O3 content could be isolated from sand fractions at 1.31–1.45 T. The XRD analyses of LMS separates obtained at 0.305–0.58 T showed only biotite and its weathered products. The XRD analyses of other LMS separates showed a concentration of different solid solution series of the amphiboles, pyroxenes, garnets, tourmaline and other iron-bearing minerals in different fractions. The LMS technique is physical in nature and provides a simple, quick and effective means of isolating iron-bearing minerals from sand fractions of soils. Key words: Liquid magnetic separation, iron bearing minerals, biotite separation, sand mineralogy

scholarly journals Removal of Impurities from Shungite Via a Combination of Physical and Chemical Treatments

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 245
Author(s):  
Toyohisa Fujita ◽  
Taichi Aoki ◽  
Josiane Ponou ◽  
Gjergj Dodbiba ◽  
Chunlin He ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Sulfur Removal ◽  
Nitrilotriacetic Acid ◽  
Microwave Treatment ◽  
Magnetic Flux Density ◽  
High Gradient Magnetic Separation ◽  
Chemical Leaching ◽  
Inorganic Acids ◽  
Mineralogical Study ◽  
Physical And Chemical

This study investigated the removal of sulfur and iron from shungite rocks through different methods after fine grinding: flotation, magnetic separation, microwave treatment, and chemical leaching. In this work, first, a mineralogical study of shungite was conducted. The carbon, silica, iron, and sulfur compositions in the as-received shungite were 45.4%, 38.3%, 4.6%, and 2.4%, respectively. In flotation, a sulfur grade of 1.4% was obtained. In the wet high-gradient magnetic separation at a magnetic flux density of 1 tesla, the iron and sulfur grades in the nonmagnetic fraction were 2.8% and 1.9%, respectively. Furthermore, the sulfur reduced to 0.2% by the 9 min microwave irradiation. In addition, chemical leaching using chelating reagents and inorganic acids was utilized to remove iron and sulfur. Nitrilotriacetic acid (NTA) could reduce the iron and sulfur grades to 2.0% and 0.9%, respectively. For leaching using reverse aqua regia, the iron and sulfur grades were reduced to 0.9% and 0.23%, respectively. For leaching using a 6N HCl with H2O2 aqueous solution, the iron and sulfur grades were reduced to 0.8% and 0.34%, respectively. Overall, chemical leaching using HCl with H2O2 was the most effective for iron and sulfur removal from shungite.

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

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