硫铁矿渣的固体废物属性特征表征

硫铁矿渣是我国禁止进口的固体废物,由于其外观和元素组成与赤铁矿极其相似,需准确对其属性进行鉴别。实验利用X射线荧光光谱(XRF)、X射线衍射(XRD)、扫描电子显微镜(SEM)、体积密度分析和pH检测手段等对样品特征进行综合表征。与赤铁矿相比,硫铁矿渣的特征主要表现在以下几个方面:主要元素为Fe、Si、Al、S,S含量比一般赤铁矿高;主要物相为赤铁矿(Fe₂O₃)、磁铁矿(Fe₃O₄)、二氧化硅(SiO₂),少量黄铁矿(FeS₂),同时还有少量水合硫酸钙(Ca(SO₄)(H₂O)_0.5)、石膏(CaSO₄·2H₂O)等硫酸盐物相,石膏等硫酸盐是赤铁矿中不常见的矿物种类;扫描电镜及能谱分析发现样品含有很多主要成分是Fe₂O₃的球状颗粒,颗粒很细,常见结团;水浸出液的pH值为4,呈弱酸性;体积密度小于1.60 t/m³。通过以上特征,能够对硫铁矿渣的固废属性进行准确鉴别。

Comprehensive characterization of solid waste identification of sintered slag of pyrite

Sintered slag of pyrite is a kind of solid waste which is forbidden to be imported in China. Since the appearance and element composition are very close to hematite, its attribute should be accurately identified. The sample characteristics were comprehensive characterized in experiments by the means of X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), scanning electron microscope (SEM), bulk density analysis and pH detection. Compared with the hematite, the sintered slag of pyrite had the following characteristics: (1) the main elements were Fe, Si, Al, S; S content was usually higher than that of hematite; (2) the phases mainly included hematite (Fe₂O₃), magnetite (Fe₃O₄) and silica (SiO₂), and a small amount of pyrite (FeS₂) as well as a small amount of sulfate phases such as semi-hydrated gypsum (Ca(SO₄)(H₂O)_0.5) and gypsum (CaSO₄·2H₂O); the sulfates such as gypsum were rare minerals in hematite; (3) SEM and XPS analysis showed that the sample contained many spherical particles of Fe₂O₃, which were very tiny and often agglomerated; (4) the pH of aqueous leaching solution was 4, showing weakly acidic; (5) the bulk density was less than 1.60 t/m³. The solid waste attribute of sintered slag of pyrite could be accurately identified according to the characteristics above.