硫化矿石自热过程的分维特性

Fractal dimension characteristics of self-heating process of sulfide ores

为揭示硫化矿石自热过程的分形特征,以从现场采集的矿石样品作为实验材料,开展矿石自热特性实验,集成小波技术和分形理论对实测温度数据进行研究。结果表明:仅矿样1、2、3和8出现明显自热现象,自热起始温度分别为136.3、178.5、195.4和200℃,在正常采矿条件下,矿石不易产生自热现象;矿样自热过程具有稳定的关联维数,验证了基于分形理论研究自热过程的可行性;在实验条件基本一致的前提下,随着自热起始温度的增大,矿样自热过程的关联维数逐渐减小,可采用关联维数来定性判断自热倾向性强弱;自热效果明显的矿样,其实验后期的关联维数大于实验前期的值,因此,可根据关联维数的变化特征来判定矿样出现明显自热的可能性,从而可减少重复实验的工作量。

To reveal the fractal characteristics of self-heating process of sulfide ores, ore samples from a copper mine were taken as experimental materials, and the self-heating characteristics were measured in laboratory. Furthermore, the measured temperature was studied by integrating wavelet technology and fractal theory. The results indicate that only the ore samples 1, 2, 3 and 8 appear obvious self-heating tendency, and their self-heating initiative temperatures are 136.3, 178.5, 195.4 and 200 ℃, respectively, which mean that they are difficult to show self-heating tendency under normal mining conditions. The correlation dimension of self-heating process of ore samples is stable, meaning that it is feasible to study the self-heating process based on fractal theory. If the experimental conditions are basically consistent, the correlation dimension of self-heating process of ore samples decreases with the increase of he self-heating initiative temperature. So, the correlation dimension can be applied to qualitatively determine the self-heating tendency. For the ore samples appearing obvious self-heating tendency in the experiment, the correlation dimension of the late period is greater than that of the previous period. Therefore, the possibility for obvious self-heating tendency of ore samples can be determined according to the variation characteristics of the correlation dimension, which can reduce the workload of repeated experiments.