钨渣制备玻璃化产物危险特性与力学性能研究

Hazardous Characteristics and Mechanical Properties of Vitrification Product of Tungsten Slag

为降低危险废物钨渣的危险特性及处置利用过程中的生态环境污染风险,采用高温熔融玻璃化处置技术,实现钨渣中毒害组分安全转化及钨渣资源化利用。以钨渣为研究对象,通过掺杂不同比例硅藻土、膨润土、氧化钙及氧化铝控制生料的碱基度,在不同熔融温度、不同保温时间条件下制备玻璃化产物。结果表明,钨渣主要重金属为Mn、As、Pb、Hg、Cr、Cu和Zn。经掺杂无定形结构调制剂,在熔融温度为1500℃、保温时间为1.0 h、碱基度为0.15~0.46条件下,用钨渣可以制备出微观结构致密、连续性好、孔隙率低、表面光滑的玻璃体,且玻璃体中As、Pb、Hg、Cr、Cu和Zn的浸出毒性远低于相关标准限值要求。制备的玻璃体结构致密,力学强度高,其坚固性范围为1.08%~3.47%,压碎值范围为2.47%~10.05%,满足普通混凝土用砂对坚固性和压碎值的质量要求。玻璃体渗透系数达1×10^(-8)~1×10^(-9) cm·s^(-1)。研究结果表明,用钨渣制备玻璃体后重金属浸出毒性及危险特征明显降低,可以实现钨渣的无害化处置,制备的玻璃体物理化学性质与防渗效果能满足混凝土用砂等潜在应用的性能要求。

In order to reduce the hazardous characteristics of tungsten slag from the manufacturing of ammonium paratungstate and to minimize the ecological environment pollution risk in the process of disposal and utilization,vitrification,considered as a promising technology for the management of hazardous wastes,is adopted to dispose the hazardous wastes for tungsten slag,which achieves the goals of reduction,innocent treatment and resource utilization.This study focused on the utilization of tungsten slag.Various proportions of diatomite,quicklime and aluminum oxide were adjusted to control the alkalinity of raw material,and the different melting temperatures as well as the holding times were set to prepare the glassy product.The results show that the main heavy metals in tungsten slag were Mn,As,Pb,Hg,Cr,Cu and Zn.By means of an appropriate technique(temperature:1500℃,holding time:1.0 h,alkalinity:0.15-0.46),a vitrified product characterized with dense homogenous structure,low porosity and smooth appearance can be made.Compared with HJ/T 299-2007 and HJ/T 300-2007,the toxic substances in the finished samples were much lower than that of the limited value in GB 5085.3-2007 and GB 16889-2008,respectively.Furthermore,the vitrified product had excellent mechanical properties(robustness value:1.08%-3.47%,crushing value:2.47%-10.05%),which were much lower than that of the limited value in Standard for JGJ 52-2006.Therefore,this vitrified product is qualified as an alternative impermeable material for landfill use since it has excellent impermeability and permeability coefficients ranged from 1×10^(-8)-1×10^(-9) cm·s^(-1).The results also show that after being disposed by the vitrification technology,the heavy metal leaching toxicity and the hazardous characteristics of vitrified samples were significantly reduced to satisfy the harmless disposal.The physical chemistry properties and anti-seepage effect of vitreous met the performance requirements of potential applications such as the concrete sand and the alternative impermeable material.