Agglomeration and bonding mechanism of typical metallurgical solid wastes

The agglomeration of solid wastes is a key factor for subsequent utilization,while the difficulty in agglomeration and high cost have become common problems in the recycling process.The disk pelletizing process was adopted,based on the optimization method by liquid binder addition,and the influence mechanism of the ratio of typical solid wastes as blast furnace dust(BFD)and sludge generated by oxygen converter gas recovery(OGS)was explored.Meanwhile,the effect of binder solution concentration on the quality of green pellets was studied.Derived from the contact angle detection and infrared spectrum analysis,the liquid bridge model was established to study the bonding mechanism.The results showed that OGS had stronger adsorption effect with binder,and the hydrophilicity of BFD was better.When the concentration of binder was higher than 0.2 wt.%,the contact angle between the binder and BFD was bigger than that with OGS,while the capillary force between particles reduced with larger contact angle.The increment in the binder concentration increased the viscous force between particles and the maximum separation distance.The ultimate drop strength and compressive strength were related to the type of viscous force,and the compressive strength reflected the strength of the force between particles intuitively,while the drop strength represented the comprehensive forces of green pellets.Reasonable combination of BFD and OGS was available for pelletizing process,while the ratio of BFD should not exceed 32.0%,and binder C was added in the form of solution with the addition amount of 0.4 wt.%,which can reduce the cost of binder by 20–30¥/t.

基于数字图像的非均匀岩土材料渗透系数研究（英文）

目的:建立一种较为快速和快速确定非均匀岩土材料渗透系数的方法。创新点:建立了一种可以从图像到数值模型的数字图像方法:通过拍照、CT等手段获取岩土材料的图像,进而通过数值分析确定等效参数。方法:1.将采集到彩色图像从RGB空间转化到HSI空间,选取识别度较高的空间进行二值化处理;2.获取二值化图像后采用邻域标记算法标记,结合本文提出的算法提取边界(图9和10);3.结合边界修正算法对锯齿状边界进行修正(图11);4.确定表征细观几何模型(图12和表1);5.绘制网格开展数值分析,确定宏观参数。结论:1.基于数值图像的非均匀岩土材料渗透系数确定方法可以较为准确地估算渗透系数,可以为工程设计提供初步依据。2.非均匀岩土材料具有明显的尺寸效应,随着尺寸增加,渗透率的变化逐渐趋于稳定;当材料视为岩石和土体的二元介质时,两种性质差异在10倍以内对宏观特性的影响较大,大于10倍之后影响减弱。3.岩土材料渗透率随着内部块石含量的增加而减小,但是内部块石的形态对渗透率也有一定的影响。