Sulfation roasting characteristics of copper‐bearing materials

Abstract

In this study, the sulfation roasting characteristics of copper-bearing ore and its flotation products as chalcopyrite concentrate and tailings were investigated in detail. For this aim, the roasting-leaching experiments and thermal analyses were conducted on the samples. As a result of the leaching of sulfated products obtained from the roasting experiments, the maximum Cu extractions were achieved as 94.7%, 99.5% and 82.7%, for run of mine, chalcopyrite concentrate and the flotation tailings, at the roasting temperatures of 550, 650 and 525°C, respectively. It was also found that the copper extractions began to decrease owing to decomposition of copper sulfates above these temperatures. It was indicated that the decomposition temperature of copper sulfates differ for each samples. On the other hand, thermal gravimetric and differential thermal analyses were subjected to identify the thermal behaviors of the samples. The results showed that the formation of metal sulfates occurred in a wide temperature range (394-650°C) for chalcopyrite. On the contrary, copper sulfation reactions took place at narrow temperature ranges of 450-560°C and 480-550°C for the run of mine ore and the flotation tailing, respectively. Figure 5. Differential thermal analyses (DTA) and thermal gravimetric (TG) curves for run of mine ore (a) and flotation tailing (b). Asia-Pacific Journal of Chemical EngineeringROASTING OF COPPER-BEARING MATERIALS 371

Cobalt and copper recovery from the ancient flotation tailings by selective sulfation roast - leaching process

“…Although the majority of research present in the literature [17,22,23] is about the chemistry and thermodynamics of the sulfation roasting process using synthetic mixtures as well as natural chalcopyrite concentrates, studies about the thermodynamic and kinetic behavior of low-grade and complex secondary metal sources are very limited. Thus, Ozer et al (2017) stated that it was not possible to obtain a selective sulfation without any additive between copper and iron in the roasting of tailings that had been stored for a long time and oxidized under atmospheric conditions, at any temperature due to their heterogeneous structure and mineralogicalchemical compositions [24]. [21] In order to improve the sulfation conditions and obtain higher selectivity, a number of promoters such as Fe 2 [23,[25][26][27][28][29].…”

“…Previous studies showed that these kinds of materials had different roasting behavior due to their mineralogical and chemical structures. It was also concluded that the decomposition of non-ferrous metal sulfates took place at a lower temperature, similar to ferrous sulfates [24]. Hence, it is worth noting that, during the recovery of copper and cobalt from that type of material, the most important issue is to prevent iron dissolution during leaching by selective sulfation [10,11].…”

Extraction of Copper from Copper-Bearing Materials by Sulfation Roasting with SO2-O2 Gas

“…In the diagram, the double oxides of copper and iron have been omitted. Considering the decomposition phenomena and energy-saving aspect, as well as some previous roasting studies, 8,33 600°C was selected as the set temperature for the experiments.…”

“…However, for low-grade ores and complex copper-bearing materials, it is often unfeasible to produce copper concentrates with the target assay for smelting. 8 What is even more relevant is that uncontrolled off-gas and fugitive emissions from pyrometallurgical plants may cause serious pollution.…”

“…Recently, some studies have been published on the sulfation roasting phenomena in copper recycling from industrial slags in a laboratory-scale furnace. 33,37,38 Besides slags, sulfation-roasting techniques have also been applied by roasting a smelting slag 31 as well as flotation tailings 8 together with pyrite. However, the roasting characteristics between different copper-bearing materials have not been compared before, and few studies have been carried out on the sulfation roasting mechanism itself.…”