High Gradient Magnetic Separation Technology Research Articles

Mechanism analysis of enhanced desulfurization of pulverized coal through high-gradient magnetic separation with microwave radiation

Dry high gradient magnetic separation technology is a low-carbon green technology. It can be embedded in a power plant to remove coal pyrite with a high-efficiency magnetic separator and remarkable magnetic properties difference between coal pyrite and coal matrix. This study selected the microwave radiation method to improve the magnetic properties difference and carried out a desulfurization experiment with a self-developed high-gradient permanent magnetic separator using the tapered iron auxiliary magnetic pole. The results demonstrate that the pyrite content and specific magnetic susceptibility increase with the decrease in particle size. The desulfurization rate did not change significantly at 25 °C. The coal sample began to appear in the thermal reaction at 450 °C, and the pyrite can become a strong magnetic property pyrrhotite. The desulfurization rate can achieve 58.70 % at 700 °C, and is equivalent to the wet washing index, due to the supply of high magnetic field force. The dynamic characteristic response of magnetic particles becomes more obvious with short time adsorption, and the probability of carrying non-magnetic particles is reduced. This study demonstrates that the high-gradient magnetic separation technology of pulverized coal enhanced by microwave irradiation is feasible.

Pre-concentration of quartz from sea sand through superconducting high gradient magnetic separation technology

ABSTRACT In this study, a superconducting high gradient magnetic separation (S-HGMS) technology was used to separate and extract quartz from sea sand. Under optimal conditions (i.e., a magnetic flow ratio of 0.085 T·s/m, slurry flow velocity of 400 ml/min, and pulp concentration of 40 g/L), the SiO2 grade increased from 79.45% of the raw material to 91.35% of quartz concentrate, and the removal rate of Al and Fe reached 91.97% and 82.10%, respectively. Weakly magnetic particles in sea sand were selectively transformed to tailings, and the pre-concentration of quartz was achieved under a high magnetic field intensity. The high magnetic field intensity and mineral magnetic differences were the critical factors influencing the magnetic separation of quartz from sea sand. The S-HGMS technology achieved effective pre-concentration of quartz from sea sand, reducing the handling capacity and providing a high-quality material for subsequent quartz refinement processes.

FeOOH and nZVI combined with superconducting high gradient magnetic separation for the remediation of high-arsenic metallurgical wastewater

Metallurgical wastewater with high arsenic (As) concentration presents important challenges to human health and the environment because of its high toxicity and carcinogenicity. Iron (Fe)-based adsorbents can effectively detoxify low As-containing wastewater but are less helpful for high concentration of As and for solid–liquid separation. Herein, an advanced strategy is proposed to dispose high As wastewater using nano-zerovalent iron (nZVI) and ferric oxyhydroxide (FeOOH) combined with superconducting high gradient magnetic separation (HGMS) technology. The superconducting HGMS technology promoted the removal of As by nZVI and FeOOH via a magnetic flocculation reaction, while simultaneously separating reaction products adsorbed As from wastewater. Interestingly, nZVI could be corroded to release Fe(II) ions which then generated Fenton reaction under aerobic conditions, facilitating the oxidization of As(III)/Fe(II) to As(V)/Fe(III) ions. The Fe(II) and Fe(III) hydrolyzed in the form of hydroxy hydroxide and further generated the magnetic flocculates and coprecipitate. The results showed that 99.06% of As was successfully removed from wastewater with an initial As concentration of 5358 mg/L, at a dosage of 20 g/L, a magnetic field strength of 5 T, and a flow velocity of 500 mL/min. Compared with FeOOH, nZVI showed more favorable adaptability for lead smelting wastewater. Removal of As from wastewater by using nZVI combined with superconducting HGMS technology has a great potential to achieve industrial application for metallurgical heavy metal wastewater.

Numerical simulation and experimental verification for magnetic field analysis of thread magnetic matrix in high gradient magnetic separation

In this study, based on the characteristics of the rod matrix and the dentate plate magnetic matrix, the thread magnetic matrix is proposed. The numerical simulation technology and model test are utilized to analyze the magnetic field distribution characteristics of the thread magnetic matrix and the effects of structure parameters on magnetic field distribution characteristics are investigated. Firstly, the numerical simulation results indicate that the magnetic induction intensity on the sharp corner of the magnetic matrix is higher, which is inferred to be the magnetic particle adsorption zone, while the valley portion is inferred to be the magnetic particle exclusion zone owing to the low magnetic induction intensity comparing to the sharp corner. Besides, the suitable sharp angle of the magnetic matrix is 60° owing to the high magnetic field force and wide magnetic particle adsorption area and the magnetic particle exclusion zone on the valley region of the threaded magnetic matrix gradually shrink with the increase of the thread pitch and the appropriate thread pitch of the threaded magnetic matrix is 1.0 mm owing to the high magnetic field force. Moreover, the results of the model test indicate that the numerical simulation results are basically consistent with the measured results which prove the numerical simulation results are credible. Furthermore, the adsorption morphology of magnetic particles demonstrates that the magnetic particles are adsorbed on the sharp corner and the magnetic particle exclusion zone in the valley region gradually shrink with the increase of the thread pitch. These results further indicate the inference which the sharp corner of threaded matrix is the adsorption zone of the magnetic particle, while the valley region is the exclusion zone is correct. This study has certain guiding significance for the development of new type magnetic matrices and the application of high gradient magnetic separation technology.

Removal of sulfur element from high-sulfur coal by superconducting HGMS technology

Coal is the most abundant fossil fuel on Earth and is used in a wide range of applications. The direct combustion of high-sulfur coal produces a large amount of sulfur dioxide, which is a toxic and corrosive gas. A new superconducting high gradient magnetic separation (HGMS) technology was studied to remove sulfur from high sulfur coal. The magnetic separation concentrate was obtained under the optimum parameters, such as a particle size of -200 mesh, a magnetic field strength of 2.0 T, a slurry concentration of 15 g/L, and a slurry flow rate of 600 ml/min. The removal rate of sulfur is up to 59.9%. The method uses a magnetic field to remove sulfur-containing magnetic material from a pulverized coal solution. It is simple process with, high efficiency, and is a new way.

Review of Coal-Fired Electrification and Magnetic Separation Desulfurization Technology

This paper briefly introduces various methods of coal desulfurization (physical desulphurization, chemical desulfurization, biological desulfurization, etc.) and analyzes some problems existing in each method. The principle and research process of friction electrostatic separation technology and high gradient magnetic separation technology in pre-combustion desulfurization technology are emphatically introduced, and the development trend of coal-fired desulfurization technology in the future is prospected.

Recovery of silicon powder from kerf loss slurry waste using superconducting high gradient magnetic separation technology

A major challenge in recycling of silicon powder from kerf loss slurry waste is the complete removal of metal particles. The traditional acid leaching method is costly and not green. In this paper, a novel approach to recover high-purity Si from the kerf loss slurry waste of solar grade silicon was investigated. The metal impurities were removed with superconducting high gradient magnetic separation technology. The effects of process parameters such as magnetic flux density, slurry density, and slurry flow velocity on the removal efficiency were investigated, and the parameters were optimized. In one lot of control experiments, the silicon content was increased from 90.91 to 95.83%, iron content reduced from 3.24 to 0.57%, and aluminum content from 2.44 to 1.51% under the optimum conditions of magnetic flux density of 4.0 T, slurry density of 20 g/L, and slurry flow velocity of 500 mL/min. The result indicates that the superconducting high gradient magnetic separation technology is a feasible purifying method, and the magnetic separation concentrate could be used as an intermediate product for high-purity Si powder.

Application Of Superconducting High Gradient Magnetic Separation Technology On Silica Extraction From Iron Ore Beneficiation Tailings

ABSTRACTComprehensive utilization of tailings resources not only solves environmental problems but also creates huge economic benefits. In this paper, fine weakly magnetic particles were extracted from iron ore beneficiation tailings and silica (SiO2) was separated and purified using a superconducting high gradient magnetic separator. Based on plenty of contrast experiments, SiO2 content of the magnetic concentrate could be increased from 68.67% to 92.57% with the selected optimal parameter combination, i.e., a magnetic flux density of 3.2 T, a pulp concentration of 40 g/L and a slurry flow velocity of 500 mL/min. The concentrate can be utilized as low-grade normal SiO2 sands for industrial use, or act as the raw materials for preparing high-purity SiO2 product.

Application and Development of Superconducting High Gradient Magnetic Separation on Environmental Protection

Superconducting High Gradient Magnetic Separation (HGMS) is widely used with its advantages of high separation efficiency, high processing speed, low-running cost and low-space requirements. The basic theory of superconducting HGMS and the applications of superconducting HGMS on environmental protection in recent years were discussed in this paper. Superconducting HGMS technology has shown a promising future.

Application of Super Conducting High Gradient Magnetic Separation Technology on Resource Utilization of Low Grade Iron Ore

Nowadays, steel industry develops rapidly. However, lots of iron ore needed by China’s steel industry are imported from abroad. China’s dependence on foreign iron ore exceeds 70%. As a result, not only have large amounts of foreign currencies been spent but also a potential threat has been posed to the economic development of our country. Therefore, it is necessary for China to serve its economic production with lots of low grade iron ore. Since traditional beneficiation methods can cause serious environmental problems, High gradient magnetic separation(HGMS) is discussed in this paper. It can recycle tailings when disposing of low grade iron ore as well as solve the environmental problems caused by tailings and arising during the production process. Besides, high gradient magnetic separator can also raise the processing efficiency of low grade iron core. Therefore, high-gradient magnetic separation can not only increase economic returns but also protect ecological environment. With the maturity of super-conduction high gradient magnetic separation technology, super-conducting high gradient magnetic separation will produce better production effects.

磁分离技术在重金属废水处理中的应用及前景

随着磁分离技术的发展，磁分离已从传统选矿应用扩展到废气、废渣、废水处理等环保领域。高梯度磁分离(HGMS)技术作为一种新型的水处理技术，目前已在分离废水中的磁性物质及COD5等有机污染物方面已得到广泛应用，超导高梯度磁分离技术在分离重金属离子等微粒径无磁性污染物方面的研究也成为热点，具有污染物去除效率高、节能环保和设备简单等优势。本文介绍了此技术的基本原理，综述了国内外学者应用该技术处理重金属废水的研究现状，并做出了展望。With the development of magnetic separation technology, the technology has extended from the traditional dressing to the field of waste gas, waste residue, waste water treatment and other en-vironmental protection. As a new water treatment technology, high gradient magnetic separation (HGMS) technology has been widely applied in the separation of magnetic material and COD5 of organic pollutants in wastewater. Study of superconducting high gradient magnetic separation technology with advantages as high removal efficiency, energy saving and simple operation in the separation of small particle size and nonmagnetic contaminants such as heavy metal ions has be-come a hot research topic. This paper introduces the basic principle of this technology, the research results of this technique for the treatment of heavy metal wastewater at home and abroad, and has made the forecast.

Circulating Tumor Cell Microseparator Based on Lateral Magnetophoresis and Immunomagnetic Nanobeads

This paper presents a circulating tumor cell (CTC) microseparator for isolation of CTCs from human peripheral blood using immunomagnetic nanobeads with bound antiepithelial cell adhesive molecule (EpCAM) antibodies that specifically bind to epithelial cancer cells. The isolation is performed through lateral magnetophoresis, which is induced by high-gradient magnetic separation technology, involving a ferromagnetic wire array inlaid in the bottom substrate of a microchannel. Experimental results showed that the CTC microseparator isolates about 90% of spiked CTCs in human peripheral blood at a flow rate of up to 5 mL/h and purifies to approximately 97%. The overall isolation procedure was completed within 15 min for 200 μL of peripheral blood. CTCs from peripheral blood of patients with breast and lung cancers were isolated with the CTC microseparator, and the results were compared with those of healthy donors. Using a fluorescence-based viability assay, the viability of CTCs isolated from peripheral blood of patients with cancer was observed. In addition, the usefulness of the CTC microseparator for subsequent genetic assay was confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR) amplification of cancer-specific genes using CTCs isolated from patients with cancer.

Application of superconducting HGMS technology on turbid wastewater treatment from converter

Turbid return water from converter is a kind of dust scrubbing wastewater with both high suspended solid concentration and high turbidity, which contains suspended particles such as iron oxide, calcium oxide, silicon oxide, and so on. Usually, it is treated with flocculating sedimentation method, but the addition of flocculant would result in the higher operating cost. In this study, the wastewater from converter was disposed by superconducting high gradient magnetic separation technology. The experimental results showed us that it very useful for both pollutants separation and reuse of wastewater from converter. With the X-ray diffraction analysis, scanning electron microscopy and particles size analysis, the results indicated that not only the ferromagnetic iron oxide, but also weak magnetic substance such as calcium oxide and silica, and nanometer particles could be magnetically coagulated and trapped. Therefore, the suspended solid concentration could be stably controlled as less than 10 mg/L, and the wastewater could be recycled completely at the magnetic field gradient of 3 T. The data reported in this study suggest that the superconducting high gradient magnetic separation technology has a great application prospect: it could be applied without changing the main conventional wastewater treatment process, and it has the advantages of low investment and operating cost, easy and simple handling, and saving water and energy as well.

High gradient magnetic separation versus expanded bed adsorption: a first principle comparison.

A robust new adsorptive separation technique specifically designed for direct product capture from crude bioprocess feedstreams is introduced and compared with the current bench mark technique, expanded bed adsorption. The method employs product adsorption onto sub-micron sized non-porous superparamagnetic supports followed by rapid separation of the 'loaded' adsorbents from the feedstock using high gradient magnetic separation technology. For the recovery of Savinase from a cell-free Bacillus clausii fermentation liquor using bacitracin-linked adsorbents, the integrated magnetic separation system exhibited substantially enhanced productivity over expanded bed adsorption when operated at processing velocities greater than 48 m h(-1). Use of the bacitracin-linked magnetic supports for a single cycle of batch adsorption and subsequent capture by high gradient magnetic separation at a processing rate of 12 m h(-1) resulted in a 2.2-fold higher productivity relative to expanded bed adsorption, while an increase in adsorbent collection rate to 72 m h(-1) raised the productivity to 10.7 times that of expanded bed adsorption. When the number of batch adsorption cycles was then increased to three, significant drops in both magnetic adsorbent consumption (3.6 fold) and filter volume required (1.3 fold) could be achieved at the expense of a reduction in productivity from 10.7 to 4.4 times that of expanded bed adsorption.

The Application of High Field and High Gradient Methods to the Magnetic Separation of Mineral Matter from Micronized Coal

Abstract In exploratory laboratory measurements, high field high gradient magnetic separation (HGMS) has removed as much as 74% of the mineral matter and 99% of the pyritic sulfur from micronized coals with mineral contents up to 16.39 wt%. Magnetic cleaning methods are limited by the fact that not all mineral matter in coal is magnetic. HGMS methods are further restricted when mineral matter levels generally exceed about 2 to 3% because of excessive capture-matrix loading which leads to poor clean coal weight yields. The use of selective flocculation of coal mineral matter and processing at high flow velocities (made possible with the use of high field superconductive magnet technology) offer hope for overcoming these process limitations and for extending use of HGMS technology to preparation of low ash and low sulfur coal-slurry fuels. Measurements of mineral matter and sulfur removals achieved in high field HGMS processing of water slurries of dispersed micronized coals are presented. Field strengths u...

Magnetische separation mit hohen flussdichte-gradienten

With high gradient magnetic separation technology developed during the last years it is possible to separate small weakly magnetic particles of micron size. Applications in water purification, in the benefication of low grade ores, in the coal desulfurization and in the industrial cleaning of kaolin clay are reviewed.

Engineering development of high gradient magnetic separators

The commercial development of high gradient magnetic separation began in 1969 when the first industrial, cyclic high gradient magnetic separators were sold to the J.M. Huber Corporation by Magnetic Engineering Associates, Sala's predecessor, for processing high grade paper coating clays. Since that time, high gradient magnetic separation for the processing of high quality clays has come to be fully accepted in the United States kaolin industry. A number of large cyclic separators of the Sala design, with capacity ratings above 60 tph have been constructed under license from Sala and installed in major U.S. clay producers' facilities. Applications of high gradient magnetic separation technology to mineral processing and water treatment have been explored(1,2,3,4). The cyclic high gradient magnetic separators utilized in the clay industry may be employed for most water treatment applications since the volume of magnetic material to be removed is a relatively small percentage of the total flow volume through the machine. In the majority of mineral separation and beneficiation problems, the feed percentage of magnetics is more than 1 to 2 percent and to solve this problem efficiently a continuous high gradient magnetic separator has been developed by us. A 15 tph continuous pilot separator is now operating in our Cambridge pilot plant and is able to process ores with the effectiveness of the cyclic high gradient magnetic separators.