攀枝花钛铁矿微波辅助磨细试验研究

【作者】 李军；

【导师】 彭金辉；

【作者基本信息】 昆明理工大学 ， 冶金物理化学， 2009， 硕士

【摘要】 矿物的碎磨过程被认为是一个能耗高且能量利用效率低的过程,为了降低能耗并提高能量利用效率,研究人员做了大量的研究工作。攀枝花的钛铁矿资源是我国重要的钛铁矿石基地,其他伴生资源如钒、铬、镍、钻、铂族等多种可利用组分也具有重要利用价值,但复杂的矿物组成及结构特点给传统的碎矿和磨矿过程带来了较大的难度。因此,寻求一种新的技术方法对该矿进行预处理,对降低磨矿过程的能耗,提高磨矿产品质量,具有重要的研究和利用价值。本研究在广泛查阅国内外论文资料的前提下,针对攀枝花钛铁矿的组成和结构特点及资源利用现状,采用微波加热技术对矿石进行预处理,重点考察微波预处理对矿石磨矿效率及后续磁选回收磁铁矿过程的影响,初步探讨了矿石的微波辅助磨细机理,确定了影响微波辅助磨细效果的主要因素,为该地区矿产资源的综合利用提供了一种切实有效的预处理新技术。论文首先分析了所选矿物的化学成分,通过试验确定了该矿石的主要矿物磁铁矿和钛铁矿具有良好的微波吸收性能。试验研究中,采用了SEM(EDS)、XRD以及激光粒度分析等手段对试验结果进行分析；以磨矿产品中-200目含量和磁铁矿磁选精矿产率的变化作为预处理效果的评价指标；确定了影响矿石被加热温度及辅助磨矿效果的主要因素是微波功率、微波加热时间、矿样重量、矿样粒度等,这些因素对后续的磁选回收磁铁矿精矿产率和回收产品品位也具有显著影响。研究发现,攀枝花钛铁矿可以很好的吸收微波能量而被迅速加热。该矿样50g在微波功率1kW、加热30s后可以被加热至300℃以上,且温升速率随微波功率的增大和微波加热时间的延长而增大,但是在额定的微波功率1kW和微波加热时间30s条件下,矿样重量为40～60g、矿样粒度为20-30mm时可以达到最高的加热温度。微波预处理矿石后,可以在矿石内部有用矿物和脉石晶粒边界上造成磨细所需要的热应力裂纹,这些裂纹显著提高了矿石的磨矿效率,并且矿物成分在预处理后没有发生改变。本研究中发现,虽然微波功率越高,预处理矿石的助磨效果越好,但需要跟处理量相配合才能在达到磨矿要求的同时做到节能；延长微波加热时间虽然可以提高被加热矿石的温度,矿石的磨矿效率没有随着微波加热时间的延长而一直提高,超过一定时间磨矿效率出现下降趋势,本研究中确定了最佳的微波加热时间是30s；在额定的微波功率和微波加热时间条件下,矿样在重量为50g、粒度20-30mm时可以达到最高的加热温度,也就具有最佳的磨矿效果。当功率为1kW时,在最佳条件：粒度20-30mm、物料量50g、加热处理30s后可以使矿样的-200目含量达到94%,较未处理过的原矿提高了28%。在对磨矿产品进行磁铁矿磁选回收的试验中发现,微波预处理可以显著提高磁铁矿的精矿产率,其回收产品品位也得到了提高。当微波功率达到3kW时,磁铁矿的磁选精矿产率由未处理时的44%提高到了72%；在各个功率条件下,其回收产品的品位均较原矿(50.2%)提高了6-8%。综上所述,利用微波加热技术对攀枝花钛铁矿进行预处理,可以显著提高矿石的磨矿效率,并且有效提高后续磁选回收磁铁矿的精矿产率及回收产品品位,基本实现了本课题研究的主要目的和意义,也为攀枝花地区的矿产资源综合利用提供了一种切实有效的矿物预处理新技术。更多还原

【Abstract】 It is generally believed that the size reduction of ores is an energy-intensive and highly inefficient process. The researchers have done many works in order to reduce the energy consumption and improve the energy efficiency. Panzhihua ilmenite resources are rich in Ti and Fe, which contain many associated minerals such as Vanadium, chromium, nickel, cobalt and platinum and so on. Both of them are important to use value. However, it has great difficulty for the traditional process of crushing and grinding because of the complex mineral composition and structural characteristics. Therefore, in order to reduce the energy consumption of grinding process and improve the quality of grinding products, it is great significance to search for a new technical approach for the pretreatment of the Panzhihua ilmenite.In this study, in connection of the composition and structural characteristics and resource utilization status of Panzhihua ilmenite and under the premise of a wide range access to paper information at home and abroad, microwave heating has been application in ore’s pretreatment. The efficiency of ore grinding and subsequent recovery of magnetite magnetic effects by microwave pretreatment was inspected. To a certain extent, the mechanism of microwave-assisted grinding and the main factors that affect the effects of microwave pretreatment have been researched. The research provides a new effective pretreatment technical for the utilization of the mineral resources in the region.In the first place, the paper analyzes the chemical composition of the selected ore. According to the testing, the main ore minerals magnetite and ilmenite have good microwave absorption properties. In the experiment, the SEM (EDS), XRD and particle size analysis are used of analyzing the test results. And the change in the -200 Mesh of mineral grinding and the recovery rate of magnetite magnetic separation are regarded as pretreatment evaluation index. So, the main factors that affect the ore’s heated temperature and the grinding effects are determined, which contains microwave power, microwave heating time, the weight of ore samples, mineral sample size, etc. These factors also have a significant impact on the magnetic separation of magnetite and the quality of recycling product.Research indicates that, the ore can be heated to above 300℃on condition that Mine-like is 50g, the microwave power is 1kW and the heating time is 30s. And the heating rate increases with the microwave power level and heating time increased. However, in the rated microwave power 1kW and heating time 30s, the ore can achieve the maximum heating temperature when the mass load is arrange from 40g to 60g and particle size of sample is 20-30mm.By the microwave heating pretreatment, the mineral liberation efficiency is improved by creating intergranular fracture on the ore and gangue grain boundaries, and the composition of ore has not been changed in the pretreatment. This study found that, although the higher power level, the better pretreatment efficiency, the handling capacity should couple with the power level so as to satisfying the grinding requirements without increasing the energy consumption. Although the extension of microwave heating time can raise the ore’s temperature, its grinding effect shows a declining trend. So this study identified the optimum heating time is 30s. On the conditions of rated microwave power level and heating time, when the mineral samples in the weight of 50g and particle size is 20-30mm, the highest heating temperature and the best grinding results would be achieved. Thus, on the optimum conditions that particle size is 20-30mm, mass load is 50g and heating time is 30s, the content of-200 Mesh can ascend to 94% when the power level is 1kW, compared with untreated ore increased 28%.According to the magnetic separation of magnetite, it is found that microwave pretreatment can significantly improve the recovery rate of magnetite. And the quality of recovery products also enhanced. When the microwave power level is 3kW, the recovery rate raise to 72%, compared with the untreated ore is 44%. On the conditions of the various power, the quality of recycling magnetite enhanced 6-8% than the untreated one (which quality is 50.2%).The result of this paper shows that, the efficiency of ore grinding can be significantly improved by utilizing microwave treated the Panzhihua ilmenite. And improve the magnetite recovery rate and the quality of recovery product effectively. To conclude, the main purpose of this research project and meaning is achieved. But also provides an effective new technique for the comprehensive utilization of mineral resources in Panzhihua region.更多还原