Leaching Kinetics of Arsenic Sulfide-Containing Materials by Copper Sulfate Solution

Abstract

The overall decrease in the quality of mineral raw materials, combined with the use of arsenic-containing ores, results in large amounts of various intermediate products containing this highly toxic element. The use of hydrometallurgical technologies for these materials is complicated by the formation of multicomponent solutions and the difficulty of separating copper from arsenic. Previously, for the selective separation of As from copper–arsenic intermediates a leaching method in the presence of Cu(II) ions was proposed. This paper describes the investigation of the kinetics of arsenic sulfide-containing materials leaching by copper sulfate solution. The cakes after leaching of arsenic trisulfide with a solution of copper sulfate were described using methods such as X-ray diffraction spectrometry (XRD), X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy analysis (EDS). The effect of temperature (70–90 °C), the initial concentration of CuSO4 (0.23–0.28 M) and the time on the As recovery into the solution was studied. The process temperature has the greatest effect on the kinetics, while an increase in copper concentration from 0.23 to 0.28 M effects an increase in As transfer into solution from 93.2% to 97.8% for 120 min of leaching. However, the shrinking core model that best fits the kinetic data suggests that the process occurs by the intra-diffusion mode with the average activation energy of 44.9 kJ/mol. Using the time-to-a-given-fraction kinetics analysis, it was determined that the leaching mechanism does not change during the reaction. The semi-empirical expression describing the reaction rate under the studied conditions can be written as follows: 1/3ln(1 − X) + [(1 − X) − 1/3 − 1] = 4560000Cu3.61e−44900/RT t.

Hydrometallurgical Recovery of Cu and Zn from a Complex Sulfide Mineral by Fe3+/H2SO4 Leaching in the Presence of Carbon-Based Materials

“…1 mL of the supernatant liquor of each leaching experiment was withdrawn at different reaction times (2,4,24,48,72, and 96 h). The sampling was carried out, as follows: first, the stirring was stopped to let the sample stand and favors its decantation.…”

“…This means that it is necessary to possess a better knowledge of the mechanism of reaction in the presence of carbon-based materials and the optimization of the properties of the carbon-based material for its potential application as catalyst in the leaching of metals from sulfide ores. Figure 3 shows the Cu and Zn extracted in the leaching solution at different reaction times (2,4,24,48,72, and 96 h). It is observed that the extraction of both metals fluctuates along time, indicating that an amount of the dissolved Cu or Zn could be adsorbed on the surface of mineral and, especially, on the carbon-based material.…”

“…The exploitation of these reserves by traditional flotation methods followed by pyrometallurgical processes (smelting-converting-electrorefining route) is in the limit of economic viability. In addition, the presence of impurities, like As, the generation of large amount of wastes, like slags, and the control of atmospheric emissions, make the research of more eco-friendly processing technologies necessary [4]. The hydrometallurgical route has the advantages of being able to process low-grade ores, to allow better control of co-products, and to have a lower environmental impact [5].…”

Advances in Mineral Processing and Hydrometallurgy

“…Karimov et al [11] submitted two articles. The first is entitled "Leaching Kinetics of Arsenic Sulfide-Containing Materials by Copper Sulfate Solution".…”

Purification of Copper Concentrate from Arsenic under Autoclave Conditions

“…In the era of industrial growth and development, enterprises involved in the processing of copper-arsenic raw materials are striving to modernize and optimize their technological processes. They make significant efforts to introduce more sophisticated and effective methods such as acid leaching [3][4][5][6], ammonia leaching [7], alkaline methods [8][9][10], bioleaching [11], and alternative methods [12][13][14][15]. However, all these innovations carry certain difficulties with them.…”