基于X射线荧光技术的金矿石在线拣选方法研究

发布时间：2018-07-05 09:15

本文选题：激光诱导击穿光谱分析法 + 机器视觉检测法　；参考：《河南科技大学》2017年硕士论文

【摘要】：对于矿脉比较薄、矿石品位较低的金矿,其开采后产生大量的废石,实际可供利用的资源比较少,这会造成资源浪费和环境污染等难题。预选是降低废石比例、提高原矿品位最有效的手段之一。目前,大部分矿山将人工拣选作为首道工序,人工利用金矿石和废石颜色上的差别将废石拣出,在一定程度上降低入选原矿中废石的比例。但由于人工拣选效率低、误拣率高,拣出的废石量有限,仍有大量的废石进入后续破碎、粉磨、洗选等工序,造成极大的能源浪费和垃圾污染。因此,探索一种适合薄矿层金矿石在线快速分离的方法非常迫切和实用。论文以河南某金矿矿石为研究对象,对金矿石在线拣选方法展开了研究。通过多种拣选方法的分析与研究,确定了一种适合于河南某金矿的矿石在线拣选方法。全文主要工作如下:1.研究识别金矿石与废石的方法。机器视觉检测法,对河南某金矿中金矿石和废石颜色进行分类,采用机器视觉检测方法分析矿石颜色特征,总结人工拣选经验和离线矿石成分分析,得出绿色废石与金矿石不容易区分。而该矿山绿色废石占废石总量较大,采用机器视觉检测法进行拣选,会造成误拣率较高或者拣出率较低的问题。激光诱导击穿光谱分析法(LIBS),采用化学元素分析法确定金矿石和废石中含量差异明显的特征元素,通过对特征元素的LIBS光谱分析,根据相对强度的差异来判定金矿石和废石。但是,分析结果不稳定,容易受到矿石表面元素含量不均匀、矿石表面不平整等因素的影响,误拣率较高。由于这两种方法都不适合用于该金矿,仍需探索更加适应于河南某金矿矿石在线拣选的方法。2.研究X射线荧光拣选方法。分析了该矿区矿脉特征和矿石特性,对该矿区的矿层、矿石成分等有了深入的了解。采用X射线荧光分析法对该矿区中金矿石和废石进行分析,探索金矿石和废石中元素含量的变化规律,将含量差异明显的元素作为特征元素。采用基本参数法、单元素分析法等计算方法,对特征元素进行X射线荧光分析,根据分析时间、分析精度等因素,确定了最终的拣选特征元素。分析了X射线荧光拣选方法的影响因素,研究了X射线荧光强度与测量距离之间的关系,并将其关系式作为修正公式编入处理软件中,修正因测量距离的变化引起的测量误差,使得X射线荧光分析法在该金矿预选中更加快速与实用。3.根据该矿区矿脉特征以及矿石特性,设计了合适的拣选工艺及相关机械装置。搭建实验台,进行了金矿石在线拣选实验。实验结果表明,在矿石预选阶段拣出了大量的废石,矿石品位提高约60%,减少了无用的能源消耗和垃圾污染,具有较大的工程应用价值。
[Abstract]:For a gold mine with thin vein and low ore grade, a large amount of waste rock is produced after mining, and the actual resources available for utilization are less, which will cause problems such as resource waste and environmental pollution. Pre-dressing is one of the most effective means to reduce the proportion of waste rock and improve the grade of raw ore. At present, most mines take artificial picking as the first working procedure, and use the difference of color between gold ore and waste stone artificially to sort out the waste rock, to a certain extent, reduce the proportion of waste rock in the raw ore. However, due to the low efficiency of manual sorting, the high rate of mispicking and the limited amount of waste rock, there are still a large number of waste rock into subsequent crushing, grinding, cleaning and other processes, resulting in a great deal of energy waste and garbage pollution. Therefore, it is urgent and practical to explore a method suitable for rapid on-line separation of gold ore from thin ore beds. In this paper, a gold ore in Henan Province is studied. Through the analysis and research of various sorting methods, a method of ore on-line sorting suitable for a gold mine in Henan Province was established. The main work of this paper is as follows: 1. The method of identifying gold ore and waste rock is studied. The color of gold ore and waste rock in a gold mine in Henan Province was classified by machine vision detection method. The color characteristics of ore were analyzed by machine vision method, and the experience of artificial picking and the analysis of offline ore composition were summarized. It is concluded that it is not easy to distinguish green waste rock from gold ore. The green waste rock in this mine accounts for a large amount of waste rock, and the machine vision detection method is used to pick the waste rock, which will cause the problem of higher missorting rate or lower sorting rate. Laser induced breakdown spectroscopy (LIBS) was used to determine the characteristic elements in gold ore and waste rock by chemical element analysis. Through the LIBS spectrum analysis of characteristic elements, gold ore and waste rock were determined according to the difference of relative strength. However, the results of the analysis are unstable and easily affected by the uneven content of elements on the ore surface and uneven surface of the ore, resulting in a higher mispicking rate. Since neither of these two methods is suitable for this gold deposit, it is still necessary to explore a more suitable method for on-line sorting of a gold ore in Henan Province. The method of X-ray fluorescence sorting was studied. The characteristics of ore vein and ore in this mining area are analyzed, and the ore bed and ore composition are deeply understood. X-ray fluorescence analysis was used to analyze the gold ore and waste rock in the mining area, and to explore the change rule of the element content in the gold ore and the waste rock. The elements with obvious difference in content were taken as the characteristic elements. The method of basic parameter analysis and single element analysis were used to analyze the characteristic elements by X-ray fluorescence. According to the time and precision of the analysis, the final picking characteristic elements were determined. The influencing factors of X-ray fluorescence sorting method are analyzed. The relationship between the intensity of X-ray fluorescence and the measuring distance is studied, and the formula is used as the correction formula to correct the measurement error caused by the change of the measurement distance. It makes X ray fluorescence analysis more rapid and practical. 3. According to the ore vein characteristics and ore characteristics of the mining area, a suitable sorting process and related mechanical devices are designed. An online sorting experiment of gold ore was carried out. The experimental results show that a large number of waste rocks are picked out in the ore pre-separation stage, the ore grade is increased by about 60 percent, the useless energy consumption and garbage pollution are reduced, and it has great engineering application value.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD953;TP391.41

【参考文献】