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![Fig. 1: Applications of antimony [20, 21]](profile/Samuel-Awe/publication/243971042/figure/fig1/AS:614066955497489@1523416379956/Applications-of-antimony-20-21_Q320.jpg)
Today, one of the major difficulties confronted during copper metallurgy is the elimination of antimony and arsenic impurities from the process. This is because the pure copper ore reserves are becoming exhausted and the resources of unexploited ores often contain relatively high amounts of antimony and arsenic. During smelting of copper concentrat...
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The Geghi Ore Belt is located within the Dastakertskoe Ore Field, which is part of the Zangezurski Ore Region, west of Kapan in South Armenia. The geology consists of Eocene Granitoids covered by Quaternary Andesite-basalt porphyritic lavas and tuffs, over a base of Proterozoic carbonate units. More recent dikes of andesite-dacite composition intru...
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... Sulphide ions dominate when pH is greater than 10. The alkaline environment is necessary to prevent sulphide ion hydrolysis and the release of toxic H 2 S gas [5]. Antimony minerals existing in galena concentrates as either antimony sulphide (Sb 2 S 3 , stibnite) or mixed sulphides such as bulangerite (Pb 5 Sb 4 S 11 ) are dissolved in alkaline sodium sulphide solutions to produce various thioanions such as thioantimonite (SbS 3 3− ) or thioantimonate (SbS 4 3− ), depending on reaction conditions. ...
The extraction of antimony and arsenic from galena concentrates by leaching with strongly alkaline sodium sulphide solution are investigated. The effects of leaching parameters including sodium sulphide and sodium hydroxide concentrations in the leaching solution, pulp density, reaction time and temperature on the extraction of antimony and arsenic are studied. It is indicated that high antimony extraction rates approaching 90–100% were obtained. However, arsenic extraction remained low at all experimental conditions considered, ranging between 2.5 and 4%, demonstrating that under these conditions, only certain arsenic-containing minerals are dissolved. The process presented is appropriate for antimony extraction with significant benefits associated with an increased value of galena concentrate and its own market value.
... The Eh-pH diagram of the stable forms for the Sb-S-H2O system is provided in Fig. 2. The most stable cations, Sb 3+ and Sb 5+ , form soluble sulfide complexes [10]. In the alkaline region at negative potentials, the solution contains mononuclear complex ions ( ...
... Eh-pH diagram of the system Sb-S-H2O at 25 ° [8,10] At the molar concentration ratio (Sb)/(S) = 1/3 the stability region for solid Sb2S3 is represented in the opposite part of the diagram. Regarding information [8,9] when the (Sb)/(S) ratio decreases to 0.25 or less, most of the area representing Sb2S3 in the diagram disappears and the solution area increases. ...
... Graph of sulfur compound forms against pH[10]. ...
This paper covers thermodynamic studies of sulfide-alkaline leaching of antimony from sulfide Au-Sb concentrates have been carried out. Sulfide alkaline leaching were chosen as the best method of dissolving antimony among other hydro and pyrometallurgical ways. The Pourbaix diagram for Sb-S-H2O, S-H2O and Au-S-H2O systems have been studied. The dissolution features of antimony and gold in sulfide-alkaline solutions have been analyzed. Conditions for efficient sulfide-alkaline leaching process, ensuring high antimony extraction along with minimization of losses of gold in the solutions were determined: Eh from -0.8 to -0.6 V at pH no less than 13, temperature – 50 °C, Sb:S molar concentration ratio = 1:3. Extensive laboratory experiments on sulfide-alkaline leaching were provided. Following parameters are recommended: L/S = 4.5:1; sodium sulfide concentration – 61 g/L; sodium hydroxide concentration – 16.5 g/L have confirmed a high antimony recovery rate into solution – 97.6%. Thereby the gold recovery into the cake of 96.9 % has been achieved.
... The high gangue content increasingly makes the processing of such deposits difficult. Furthermore, their complex nature and significant concentrations of undesirable metals such as Fe, Co, Mn, Pb, Zn, As and Ni, also leads to high processing costs (Awe, 2013). ...
... Besides the concerns of consumption by calcite of H2SO4, the reagent is aggressive with poor selectivity for copper, leading to the excessive dissolution of certain metals: Fe, Mn, Pb, Co, from the ore matrix into the leachate solution as impurities. The presence of these metals in the leachate usually result in additional processing cost in the downstream processing for copper recovery (Ekmekyapar et al., 2003;Künkül et al., 2013;Awe, 2013). These impurities have negative impact on the quality of copper metal produced unless removed (Fillipou et al., 2007). ...
... The heterogeneous fluid-solid reaction systems have been applied in hydrometallurgical and chemical reaction processes (Awe, 2013). The shrinking core model was used to investigate the mechanism of the leaching process because of its wide application (Aydogan et al., 2005;Levenspiel, 1999;Baba and Adekola, 2010;Awe, 2013, Baba et al., 2013. ...
Copper oxide ore was pre-concentrated using near infrared sensor-based method and classified as product, middling and waste. The product and middling fractions were leached with ammonium chloride reagent. The effect of temperature, ammonium chloride concentration, solid-liquid ratio, stirring speed and particle size experimental variables were investigated. Mineralogical and chemical analysis of the ore fractions indicated that copper content was in accordance with the pre-concentration strategy, with the product having a higher concentration than the middling and waste. The rate of copper extraction was found to be higher in the product than in the middling sample which further supports the near infrared classification, QEMSCAN ® , X-ray diffraction, SEM mineralogical and X-ray florescence and Inductively coupled plasma Mass spectrometry chemical data. It was revealed that the leaching rate increases with increasing ammonium chloride concentration, temperature and decreasing ore particle size, stirring speed and solid-liquid ratio. Analysis of the experimental data by shrinking core model indicated that the dissolution kinetics follow the heterogeneous reaction model for the chemical control mechanism where the activation energies of 45.9 kJ/mol and 47.5 kJ/mol for product and middling fractions respectively were obtained. Characterization of the residue obtained at optimum leaching condition with X-ray diffraction suggests that copper was selectively leached when compared to the profile of the raw ore. The trace levels of metals associated with abundant X-ray diffraction profiles of residue found in the leachate further confirm the selective leaching process.
... Unfortunately, most of these hydrometallurgical processes are not selective and, hence, result into complications in the separation process [7]. However, alkaline sulfide leaching has been reported elsewhere [8][9][10][11][12][13][14] as a potential hydrometallurgical technique for selective dissolution of arsenic, antimony, mercury, and tin from materials containing them. Other metals, like copper, zinc, bismuth, lead, iron, and nickel, form an insoluble metallic sulfide and hence precipitate from the solution [15]. ...
The aim of the present study is to selectively extract antimony and arsenic from decopperization slime through alkaline sulfide hydrometallurgy with a view to recycle the obtained solid residue within the copper smelter, and also regenerate the sulfide lixiviant during the process. Rechtschaffner experimental design was used to evaluate the joint influence of several experimental parameters such as leaching temperature, Na2S concentration, solid concentration, and reaction time on the extraction of antimony and arsenic from the material. The most active parameters influencing the extraction of the metals are solid concentration and reaction period. In addition, the results show that solid concentration interacted strongly with the leaching time and slightly with reaction temperature, which is an indication that solid concentration is the predominant influencing factor in removing antimony and arsenic from the material. It is also indicated from the results that about 95% Sb and 89% As were extracted when 50 g/L of the decopperization slime was dissolved in alkaline sulfide lixiviant containing 200 g/L Na2S + 20 g/L NaOH at 60 °C for 24 h. Moreover, analysis of the leach residue reveals that copper sulfide and lead sulfide remain as the main constituents of the residue. The bismuth-containing mineral phase was not observed in the residue because of its low concentration, and also the Sb/As-bearing mineral phases were not detected due to the selectivity of the leaching reagent to the metals. Based on the experimental results from this investigation, a process flowsheet for the alkaline sulfide treatment of a decopperization slime was proposed with a view to eliminating its antimony and arsenic contents in a sustainable manner.
... But the presence of arsenic and antimony impurities creates a build-up of these metals in the copper circuit, leading to problems during copper refining processes. Arsenic affects the electric conductivity of copper while antimony makes the copper product brittle (Viñals et al., 2003;Awe, 2013, Wang, 2004. Therefore, a removal or reduction of these impurities to acceptable levels is a necessary step before speiss can be recycled in the smelter for the recovery of valuable metals. ...
... wt% in copper (Cu) concentrates (Larouche, 2001). However, Sb has usage, for example as alloy in lead (Pb) batteries, if it can be separated from massive sulphide ores (Anderson, 2012;Awe, 2013). In addition to producing valuable products from massive sulphide ores, the Sb content of the tailings ought to be considered since the Sb content of the tailings is a potential environmental hazard, particularly in the discharge to rivers, comparable to arsenic (Wilson et al., 2010). ...
... Finer grinding could be considered, but this has cost implications and overgrinding might even have negative effects on the flotation of the main base metal sulphide minerals (Trahar, 1981;Trahar and Warren, 1976). However, it is expected that all main Sb minerals from Rockliden can be removed from the Cu-Pb concentrate by alkaline sulphide leaching before the product is sent to the smelter (Awe, 2013;Minz, 2013 and references therein). Thus, a forecast of the Sb grade of the Cu-Pb concentrate might help to evaluate an alternative treatment of the Cu-Pb concentrate. ...
The Rockliden massive sulphide Zn–Cu deposit contains minor amounts of Sb minerals. The Sb mineralogy is complex in terms of composition, micro textures and mineral associations. The main Sb minerals comprise tetrahedrite, bournonite, gudmundite and Sb–Pb sulphides such as meneghinite. The presence of these minerals is especially critical to the quality of the Cu–Pb concentrate. To study how they are distributed in a simplified flotation circuit and what controls their process behaviour Sb-rich drill core samples were selected from the Rockliden deposit and a standard laboratory flotation test was run on the composite samples. Scanning electron microscope-based automated mineralogy was used to measure the Sb mineralogy of the test products, and the particle tracking technique was applied to mass balance the different liberation classes to finally trace the distribution of liberated and locked Sb minerals. The mineralogical factors controlling the distribution of Sb minerals are mineral grain size, the degree of liberation, and associated minerals. Similarities in the distribution of specific particle types from the tested composites point towards systematics in the behaviour of particles and predictability of their distribution which is suggested to be used in a geometallurgical model of the deposit.
Antimony dissolution in alkaline sulfide solution is the most common wet method of extraction of antimony from primary and secondary sources. In this research, the effect of adding crystallization step before electrowining step on improvement of antimony extraction from sulphide ores was studied. Effect of time and temperature of crystallization step on the removal of antimony and other constituents from leaching solution was explored. Furthermore, effect of crystallization step on some important process parameters such as antimony recovery, current efficiency, type of antimony precipitation on cathode plate and purity of produced antimony was investigated. According to the results, a decrease in the temperature and an increase in the time of crystallization step tend to enhance antimony separation to solid crystals. Removal degree of 95.2 wt% was the best result for antimony separation which was achieved after 2 hour crystallization at 5 C. Additionally more than 90% of As, Fe, Al and sulfur components such as sulphates and thiosulphates were remained in the liquid phase. Results of electrowining step show that high concentration of sulfur component in the solutions that did not pass crystallization step, leads harmful reactions to take place at the electrodes and consumption of electrical energy. Therefore, removal of these harmful components by crystallization causes an increase in the antimony production rate and current efficiency and also improves antimony adherence to the cathode plate. Moreover, the purity of final antimony product was increased from 98.5 to 99.6 wt%.
The Rockliden Zn–Cu volcanic-hosted massive sulphide deposit is located approximately 150 km south of the Skellefte ore district, north-central Sweden. Most of the mineralisation is found at the altered stratigraphic top of the felsic volcanic rocks, which are intercalated in the metamorphosed siliciclastic sedimentary rocks of the Bothnian Basin. Mafic dykes cross-cut all lithological units, including the massive sulphides, at the Rockliden deposit. The relatively high Sb grade of some parts of the mineralisation results in challenges in handling of the Cu–Pb concentrate in the smelting process. The aim of this study is to characterise different host rock units and ore types by their main mineralogy, as well as by their trace mineralogy with focus on the Sb-bearing minerals. Ore types are distinguished largely on the basis of their main base-metal bearing sulphide minerals, which are chalcopyrite and sphalerite. Several Sb-bearing minerals are documented and differences in the trace mineralogy between rock and ore types are highlighted. Based on the qualitative ore characterisation, rock- and ore-intrinsic parameters, such as the pyrite, pyrrhotite and magnetite content of the massive sulphides, the trace mineralogy and its association with base-metal sulphide minerals, are outlined and discussed in terms of relevance to the ore processing. © 2014 Institute of Materials, Minerals and Mining and The AusIM.
