磁力旋流器脱泥浓缩规律研究

发布时间：2018-07-20 19:10

【摘要】：铁矿石是钢铁工业的主要原料。炼铁工业要求较高的铁精矿品位，国内外铁精矿生产发展趋势主要有三个方面，即新型高效磁选设备、反浮选工艺以及磁选和反浮选联合流程。在磁铁矿选矿过程中，大量细泥的存在对选别过程和精矿产品的质量有重大影响，为给选别过程创造有利条件，得到合格的精矿，通常要对物料进行入选前的脱泥作业。因此，本论文设计、使用磁力旋流器对磁铁矿进行脱泥浓缩试验研究，以达到脱除细泥“提铁降硅”的目的。设计并加工Φ100mm磁力旋流器，构建试验系统，研究了旋流器锥角、磁场位置和大小、组合磁场、入料压力和浓度等对磁力旋流器脱泥浓缩效果的影响。 90°锥角下磁场作用在锥中时，在单线圈作用下得到了产率82.20%、铁品位61.49%、SiO2含量10.75%的底流产品；采用双线圈增大磁场强度和磁场作用空间，可使底流铁回收率达到98.96%，底流品位从57.95%提高到60.36%，进一步降低溢流中金属损失，达到了脱除部分细泥，提高底流品位的目的，可使矿浆浓度从15%浓缩至48.83%，降低后续选别作业的处理量。磁力旋流器对较细粒级磁铁矿物料脱泥效果明显，对粗粒级物料分选效果不明显，将粗粒级预先去除有利于提高底流产品的铁精矿品位。 20°锥角下多线圈磁场作用在锥中位置时效果较好，较小电流时底流产率即可达到90.91%，金属损失很少；单线圈作用下，随着电流的增大，底流产率随之增大，溢流和侧溢流产率都随之减小，0.08MPa压力时，随着电流的增大，底流产率从67.49%升至90.37%，溢流产率从28.86%降至8.35%，侧溢流产率从3.65%降至1.28%，较低的压力有利于减少金属损失；随着入料浓度的增大，底流产率减小，高浓度下增大了金属的损失，15%质量浓度效果较好。在溢流室施加磁场，永磁场作用下未能实现进一步回收金属的目的；电磁场作用下可以不同程度地增加底流和侧溢流产率，降低溢流产率，减少金属损失；在锥体中部和溢流室同时施加磁场，可强化底流的金属回收，但对侧溢流进一步回收基本无效。采用ANSYS有限元分析软件的磁场分析功能，对所用磁系进行了模拟。模拟结果表明：由ANSYS模拟得到的线圈中心轴线上的磁感应强度变化与实际测量值规律一致，吻合度较高，可以较真实的反应磁场特性。线圈通电后轴向和径向上均有磁场力的存在，线圈上下平面附近磁场梯度较大，磁场力也相应较大，，可以吸引磁性颗粒向该区域聚积；越靠近线圈内壁磁场梯度越大，磁性颗粒在径向上受到的磁场力指向外部，可以强化其向外旋流的运动。磁力旋流器对磁铁矿具有一定的脱泥作用，可提高磁铁矿精矿品位，是一个良好的磁力浓缩设备。
[Abstract]:Iron ore is the main raw material of iron and steel industry. The development trend of iron concentrate production at home and abroad mainly includes three aspects: new high efficiency magnetic separation equipment reverse flotation process and combined process of magnetic separation and reverse flotation. In the process of magnetite processing, the existence of a large amount of fine mud has a significant impact on the separation process and the quality of concentrate products. In order to create favorable conditions for the separation process and to obtain qualified concentrate, the material usually needs to be deslimed before being selected. Therefore, in this paper, the magnetic cyclone is used to study the desliming and concentration of magnetite in order to remove the fine mud from iron and silicon. The 桅 100mm magnetic hydrocyclone is designed and fabricated. The test system is constructed. The cone angle, magnetic field position and size, combined magnetic field are studied. The effect of feed pressure and concentration on the desliming effect of magnetic hydrocyclone. When the magnetic field is in the cone at 90 掳angle, the bottom flow product with the yield of 82.20 and the iron grade of 61.49SiO2 10.75% is obtained under the action of single coil. Using double coils to increase magnetic field intensity and magnetic field action space, the recovery rate of bottom flow iron can reach 98.96 and the bottom flow grade will be raised from 57.95% to 60.36. The loss of metal in overflow can be further reduced, and the purpose of removing some fine mud and improving bottom flow grade can be achieved. The pulp concentration can be concentrated from 15% to 48.83%, and the treatment capacity of subsequent separation operation can be reduced. The effect of magnetic cyclone on desliming of fine grained magnetite is obvious, but it is not obvious for coarse grained material. The iron concentrate grade can be improved by removing coarse-grained grade in advance. Under 20 掳cone angle, the effect of multi-coil magnetic field in the cone is better, the bottom flow rate can reach 90.91 when the current is small, and the loss of metal is very little. Under the action of single coil, the bottom flow rate increases with the increase of current. When the overflow rate and side overflow rate decrease with 0.08MPa pressure, the flow rate increases with the increase of current. The bottom abortion rate increased from 67.49% to 90.37%, the overflow rate decreased from 28.86% to 8.35, and the side discharge rate decreased from 3.65% to 1.28%. At high concentration, the loss of metal is increased by 15% mass concentration. When the magnetic field is applied in the overflow chamber, the purpose of further recovery of metal can not be realized under the action of permanent magnetic field, and the bottom current and side overflow rate can be increased, the overflow rate and metal loss can be reduced in varying degrees under the action of electromagnetic field. When the magnetic field is applied simultaneously in the middle of cone and overflow chamber, the metal recovery of bottom flow can be enhanced, but the further recovery of contralateral overflow is basically ineffective. The magnetic field analysis function of ANSYS finite element analysis software is used to simulate the magnetic system. The simulation results show that the variation of magnetic induction intensity on the central axis of the coil obtained by ANSYS is consistent with the measured values, and the degree of coincidence is high, and the real response magnetic field characteristics can be obtained. The magnetic field force exists in the axial and radial direction after the coil is electrified. The magnetic field gradient near the upper and lower plane of the coil is larger, and the magnetic field force is also larger, which can attract the magnetic particles to accumulate in this region. The closer the magnetic field gradient is to the inner wall of the coil, the greater the magnetic field gradient is. The magnetic force acting on the magnetic particles in the radial direction points to the outside, which can strengthen the motion of the outward swirling flow. Magnetic cyclone has a certain desilting effect on magnetite, it can improve the grade of magnetite concentrate, and it is a good equipment for magnetic concentration.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD457;TD951

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