| Aiming at the current situation of industrial applications of high gradient magnetic separation equipment, this paper analyzes the advantages and disadvantages of different types of magnetic matrices in industrial applications. A kind of magnetic matrix has been designed in the study which can be used in high intensity magnetic separation and can enhance the recovery of fine and weak magnetic iron mineral particles. The magnetic field characteristics of unity magnetic matrix and combined salient magnetic matrices have been studied with Ansoft 3-demention magnetic field imitation technology. System magnetic separation tests had been performed on specularite pure minerals magnetic adsorption behavior on surface of salient rods and separating effects of several hematite samples. The predicted results of 3-demention magnetic field imitation have been certified. Lately the reasonable matrix structural parameters which are good for enhancing the fine iron minerals particles recovery have been made out.Study the mineral kinds of specularite pure mineral, determine the Fe content, measure Fe bearing minerals and Fe distribution rate in them by several analysis and detecting methods, such as XRD, chemical analysis, Fe phase analysis and detecting with micro-scope. As the study results reveal,α-hematite is the main Fe-bearing mineral in specularite, and 99% Fe of all Fe-bearing minerals distributes in α-hematite. The hematite content of coarser particles is relatively low. The Fe bearing minerals’ liberation degree in different grain size fractions have been measured. By chemical analysis, screening and elutriation, Fe phase analysis etc. methods, ores characteristics and properties of several kinds have been studied, including the tailings of high intensity magnetic separation scavenger in Meishan Mining Cor. Bao Steel Ltd.,feed and tailings of high intensity magnetic separation in Dong’ anshan, tailings in Shilu Hainan. As the results shows, hematite is the main Fe-bearing minerals in the several kinds of weak magnetic iron ore samples, the -0.043mm particles in ROM takes up over 80%. The hematite is one of the object Fe-bearing mineral in the weak magnetic iron ores.The magnetic field characteristics of unity magnetic matrix and combined salient magnetic matrices have been studied with Ansoft 3-demention magnetic field imitation technology. Study the effect of assisted structure parameters on magnetic field distribution rule of the unit matric, such as pole shape, angle, and pole distance. The inter-affecting mechanism of magnetic induction field among matrices in multi-matrices combined system had been revealed. The impossible effect of magnetic field characteristics of different matrices on separation process had been predicted. As results reveal, the magnetic flus density and magnetic field irregularity of salient matrices have been increased comparing to rod magnetic matrix with identical diameter, which is much more prominent in low background magnetic induction intensity. It’s not good for separation if the pole angle is too obtuse or acute. The reasonable pole angle determined is 60 degree.When the poles’ center distance is 2mm or 4mm, the alternative appearance frequency of magnetic induction density of pole point and sunken part is high. The magnetic field intensity irregularity increases along the magnetic matrix shaft direction, and the better separation effect is expected. The smaller the center distance of matrices is, the more prominent magnetic induction cloud nestification is, the greater magnetic induction intensity of surface poles and their clearance is. Magnetic induction intensity of matrix decreases as the center distance increases. And if the center distance increases to a certain degree, the inter-affection between matrices weakens and magnetic induction distribution is identical to that unity matrix.Separation tests have been performed in horizontal and vertical magnetic field of different matrices on several samples, including fine hematite in India, high intensity magnetic separation limonite tailings in Yingde Guangdong Provience, high intensity magnetic scavenger separation tailings in Meishan Mining Bao Steel Corp. It’s assured preliminarily that the magnetic field gradient is enhanced by the poles’s edges on the salient matrix surface, what’s more the magnetic force between matrix and magnetic particles is strengthened, and the recovery in concentrate is increased. It’s proved that changing surface structure of matrix is an effective way to enhance the effect of magnetic field gradient and to increase magnetic force through exploratory tests. The separation effect identical to smaller diameter matrix can be obtained by decreasing matrix’ center distance and increasing filling ratio in certain degree. Although the magnetic induction density of bigger matrix diameter is increased, but the matrix specific area decreases, so the effective adsorption area decreases. While the smaller diameter matrix is, the more rapidly magnetic field gradient and specific area increase, but filling ratio decreases, while magnetic loss increases. So the matrix diameter and filling ratio should be determined according to different processing materials.The effects of salient matrix arrangement and pulsating fluid on hematite pure minerals magnetic adsorption behavior have been studied by adsorption tests of specularite pure minerals in different grain size fractions. The effects of matrix structure parameters on adsorption behavior of weak magnetic pure minerals have also been investigated. Further more, the affecting mechanism of grain size on pure mineral magnetic adsorption system has been found. Lately the predicted results of 3-demention magnetic field imitation have been certified. As the above research results showed that the adsorption rate of staggered pattern matrix on specularite is higher than that of parallel arrangement matrix. If the feed grain size decreases, the difference value of adsorption rate between staggered pattern matrices and parallel arrangement matrices increases. Comparing to without pulsating fluid, the adsorption difference of the matrix with homogeneous clearance but different pole distance is much more prominent when adds pulsating (pulsating stroke length 11.4mm, stroke frequency 150 times/min). The adsorption performance is the best when salient pole magnetic matrices’pole center distance is 1.0mm. In the same clearance, the magnetic force of salient pole magnetic matrices on specularite pure minerals is greater and the recovery is higher than that of rod magnetic matrices.System magnetic separation tests had been performed on several samples including high intensity magnetic separation feed and tailing in Dong’anshan, tailing in Shilu Hainan. The differences of matrix structural parameters on separation effect have been studied. The reasonable matrix structural parameters which are good for enhancing the fine iron minerals particles recovery have been made out. The separation behaviors of matrices on weak magnetic materials have been found. The affecting rules of matrix parameters and structures on grain size distribution of magnetic products have been worked out. Technology and economic indices of salient pole magnetic matrices and rod matrices have been compared. As research results reveals, to high intensity magnetic separation feed in Dong’anshan, separation effect is the best when the pole center distance between poles is 1.0mm and clearance between matrices is 3mm. While to high intensity magnetic separation tailing in Dong’anshan and Shilu Hainan, separation result is the most effective when the pole center distance between poles is 0.5 mm and clearance between matrices is 2mm. Grain size limit of magnetic products recovered by salient pole magnetic matrices is lower than that by rod matrices. And the recovery has been increased due to the recovery of fine particles, the aim of enhancing fine particles’recovery has been achieved. When the magnetics’ recovery of the two kind matrices reach to the same value, the background magnetic field of salient pole magnetic matrices needed is 0.2T lower than that of rod magnetic matrices, which is good to energy saving and reduction of high intensity magnetic separators.The results of the dissertation provide new technology thoughts for the recovery of enhancing weak magnetic minerals and high intensity magnetic separation, offer direction guidance and theory support for matrices development and improvement, and supply important technology accumulations for separation indices of refractory iron resources with high intensity magnetic separation. |
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