Arsenic Removal from Arsenopyrite-Bearing Iron Ore and Arsenic Recovery from Dust Ash by Roasting Method

Abstract

In most cases, arsenic is an unfavorable element in metallurgical processes. The mechanism of arsenic removal was investigated through roasting experiments performed on arsenopyrite-bearing iron ore. Thermodynamic calculation of arsenic recovery was carried out by FactSage 7.0 software (Thermfact/CRCT, Montreal, Canada; GTT-Technologies, Ahern, Germany). Moreover, the arsenic residues in dust ash were recovered by roasting dust ash in a reducing atmosphere. Furthermore, the corresponding chemical properties of the roasted ore and dust ash were determined by X-ray diffraction, inductively coupled plasma atomic emission spectrometry, and scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy. The experimental results revealed that the arsenic in arsenopyrite-bearing iron ore can be removed in the form of As 2 O 3 (g) in an air or nitrogen atmosphere by a roasting method. The efficiency of arsenic removal through roasting in air was found to be less than that in nitrogen atmosphere. The method of roasting in a reducing atmosphere is feasible for arsenic recovery from dust ash. When the carbon mass ratio in dust ash is 1.83%, the arsenic removal products is almost volatilized and recovered in the form of As 2 O 3 (g).Processes 2019, 7, 754 2 of 12 decreasing greatly in the earth, and arsenic-bearing ore needs to be comprehensively utilized through ore blending. Some metallurgical enterprises at home and abroad, such as Peru, Chile, Philippines, France, Mexico, and China, have adopted some arsenic-bearing ore in the metallurgical industry [11]. When these arsenic-bearing ores are used, they are faced with the problem of arsenic removal from ores and the problem of arsenic-bearing dust treatment from the point of view of environmental protection.Arsenic can be removed from arsenic-bearing ore by a roasting or sintering method due to the volatile nature of arsenic and its compounds [12]; thus, some scholars have explored the appropriate arsenic removal conditions by performing roasting or sintering experiments. Yin et al. and Lu et al. studied arsenic removal from copper-silver ore using a roasting method [13,14], and the impact of different parameters (e.g., temperature, atmosphere, and roasting time) on the arsenic removal ratio was also evaluated. Lu et al. investigated arsenic removal from arsenic-bearing iron ore during the sintering process [15,16]. The effects of temperature, bed depth, gas pressure, and coal ratio on arsenic removal during the sintering process were studied, and the reasonable technical parameters were obtained. In addition to the arsenic removal tests by roasting and sintering methods, a number of scholars also carried out thermodynamic calculations on arsenic removal, and discussed the arsenic-bearing products and suitable conditions for arsenic removal. Chakraborti and Lynch analyzed the As-S-O vapor system [17] and further identified the importance of bed depth in the rapid release of arsenic from arsenical materials under an oxidizing atmosphere. Contreras et al. ev...

Arsenic removal procedure for the electrolyte from a hydro-pyrometallurgical complex

“…suggesting the decomposition of iron arsenate anhydro (Cervando and Viraca, 2013;Cheng et al, 2019), according the chemical Eq. 3.…”

Special Issue on “Process Modeling in Pyrometallurgical Engineering”

“…Cheng et al [4] investigated the removal of arsenic from iron ore through roasting in air and nitrogen. They reported higher removal ratios using a reducing atmosphere.…”

First‐principles study on the effect of arsenic impurity on oxidation of pyrite surfaces

“…This leads to an inseparable relationship between As‐bearing pyrite and Au in nature [8–10]. In addition, in mineral processing, effective removal of As can prevent the generation of As compounds that pollute the environment, improves product quality, and enhances the safety of work environments [11–13]. Therefore, to effectively prevent acid mine drainage, protect human health and the ecological environment, and effectively remove As, it is important to clarify the microscopic mechanism of the effect of As impurities on the initial oxidation of the pyrite surface.…”