Thermal analysis of Indonesian copper sulphide

The development of extracting hydrometallurgical process for copper sulphide mineral becomes one of the promising fields, not only for the copper production but also for the production of metal by-products. The advantage of the thermal analysis is to get the phase form of the minerals on a certain temperature. With this result, the chosen metal can be selectively extracted. The goal of this study is to understand the thermal reaction of the copper sulphide as the basic data to develop a process flowsheet of extracting copper and other important metals from the copper concentrates by using an alternative new hydrometallurgy process to increase the value of the minerals. The thermal behaviour was investigated by simultaneous thermal analysis consisting of differential scanning calorimetry (DSC) in combination with thermo gravimetry (TG) and fourier transform infrared (FTIR) spectroscopy. Samples were pre-treated by roasting at the several temperature transitions and subsequently characterized by XRD and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS).

Structural and geochemical ore-forming processes in deformed gold deposits: towards a multi-scale and -method approach

Integrating structural control on mineralisation and geochemical ore-forming processes is crucial when studying deformed ore deposits. Yet, structural and geochemical data are rarely acquired at the same scale: structural control on mineralisation is typically investigated from the district to the deposit and macroscopic scales whereas geochemical ore processes are described at the microscopic scale. The deciphering of a deformation-mineralisation history valid at every scale thus remains challenging.This study proposes a multi-scale approach that enables the reconciliation of structural and geochemical information collected at every scale, applied to the example of the Galat Sufar South gold deposit, Nubian shield, northeastern Sudan. It gathers field and laboratory information by coupling a classical petrological-structural study with high-resolution X-ray computed tomography, electron back-scattered diffraction and laser ablation inductively-coupled plasma mass spectrometry on mineralised sulphide mineral assemblages.This approach demonstrates that there is a linear control on mineralisation expressed from the district to microscopic scales at the Galat Sufar South gold deposit. We highlight the relationships between Atmur-Delgo suturing tectonics, micro-deformation of sulphide minerals, syn-pyrite recrystallisation metal remobilisation, gold liberation and ore upgrading. Our contribution therefore represents another step forward a holistic field-to-laboratory approach for the study of any other sulphide-bearing, structurally-controlled ore deposit type.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5635726

Removal of Major Phosphate Impurities by Flotation using DTAB Collector

Removal of phosphate impurities is a prerequisite for using phosphate ores in different applications. The flotation process is one of the most promising processes that have been used to improve the phosphate grade. However, the flotation performance depends on the type of the associated impurities to valuable minerals due to their different flotation behaviour that needs more attention. In this paper, the flotation response of impurities at different pH and dodecyl tri-methyl ammonium bromide (DTAB) collector concentrations was investigated using the statistical design of experiments. The results indicated that some impurities were completely removed such as silica and alumina while others are only partially removed at about 72% and 38%, respectively. Thus, based on the impurities response to flotation and their rejection by flotation using DTAB collector, they are classified into two groups. The first group is SiO2, MgO, and Al2O3, while the second group includes only sulphide mineral (FeS2). The lowest rejection percentage for pyrite is due to its chemical composition as a sulphide mineral that has a different interaction with DTAB collector in comparison to first group minerals.

The Solution Interaction of Tetrathionate Ions and Sodium Isobutyl Xanthate and Its Effect on the Flotation of Galena and Chalcopyrite

Tetrathionates have been found in significantly high concentrations in recycled process waters from massive sulphide ore processing plants. These polythionates react with xanthate added to flotation pulps thus reducing xanthate dosages in solution potentially affecting flotation performance. The current study focused on the effect of the tetrathionate-xanthate reaction on sulphide mineral recoveries. Ore dissolution studies confirmed the generation of tetrathionates by copper-lead-zinc ores. In 20 min, the tetrathionates consumed more than half of the xanthate in solution at pH 7. Rest potential measurements and Fourier transform infrared spectroscopy (FTIR) showed that the degree of collector-mineral interactions of xanthate and both galena and chalcopyrite was greatly reduced in the presence of a 2000 mg/L tetrathionate solution. Microflotation tests showed that chalcopyrite recovery was less sensitive to tetrathionates as indicated by small changes in mineral recoveries. Galena was sensitive to the action of tetrathionates on the mineral surface as the galena recovery significantly declined when floated with xanthate as a collector in both a 500 mg/L tetrathionate solution and a 2000 mg/L tetrathionate solution. These fundamental results lay a sound base on which more discussion into the significance and the effect of tetrathionates on flotation performance of sulphide ores can be developed.

Lipid-reducing effects of sulphate-sulphide mineral water in patients with knee osteoarthritis

Background/Aim: The positive effect of thermal mineral waters on human health has been known for a long time. Many pathophysiological mechanisms of action of balneotherapy are not specified. Patients with gonarthrosis often have elevated values of serum lipids. This study aimed to examine the effect of drinking sulphate-sulphide thermo mineral water on the lipid status of patients with gonarthrosis. Methods: A prospective clinical study followed 60 patients, both sexes, mean age 65.02 ± 1.03, with gonarthrosis. All inpatient underwent physical treatment with topical application of sulphate-sulphide mineral water. Patients of group A (N = 30) had the use of this mineral water as an additional therapy by drinking, unlike patients of group B (N = 30) who drank plain water. The level of serum lipids of these patients was monitored at admission and 4 weeks after. The variance analysis test (ANOVA) with a level of statistical significance p < 0.001 was used for statistical analysis. Results: A significant reduction in the levels of all lipid fractions in the serum of patients with gonarthrosis was found 4 weeks after the completion of inpatient physical treatment in both study groups. This decrease was statistically significant in patients of group A (p < 0.001). Conclusion: Drinking sulphate-sulphide mineral water in patients with gonarthrosis shows a positive effect on the reduction of serum lipid levels in the short-term follow-up period.

Determining Acid and Metalliferous Drainage Potential of Waste Rock on a Mine

Acid and Metalliferous Drainage (AMD) is recognised as serious environmental problem in the mining industry. This is because environmental issue of AMD poses serious threat to water quality, vegetation cover and social licence of the mining operations. AMD occurs when reactive sulphide bearing materials are exposed to oxidising conditions. It has now become imperative for some mining companies to test sulphide bearing minerals for their AMD potential before major mining excavations are done. This work determines the AMD potential of fifty (50) waste rock samples from a Mine using Acid Base Accounting (ABA) techniques. Mineralogical studies on the sample indicated that the major sulphide mineral assemblages present were pyrite, arsenopyrite and chalcopyrite. Paste pH showed that 20% of the samples had undergone weathering and as such AMD generation had already started. Approximately 22% of the sample had conductivity levels between 1000 to 10,000 µS/cm and this shows a typical AMD chemical characteristic of high salinity. Acid Base Accounting showed that 32% of the samples were acid generating. Exactly 16% were non-acid forming and 52% were uncertain. The analysis showed that the potential for AMD generation exists for the waste rock material and can affect the local environment, specifically water quality if preventive measures are not taken. Keywords: Sulphide, Waste Rock, Acid Base Accounting, Paste pH, Conductivity

Infrared Thermography: A Method to Visualise and Analyse Sulphide Oxidation

Environmental testing of sulphidic ores and wastes aims to assess the release of metals and metalloids at acid pH conditions and the samples’ likelihood to produce acid rock drainage (ARD). However, the majority of established ARD tests measure geochemical properties of samples and cannot visualise the exothermic oxidation reactions and their intensity leading to metalliferous drainage in all pH environments. This paper proposes a new protocol to detect and visualise the sulphide oxidation in ores and wastes. Six nearly monomineralic sulphides were crushed, sieved to two size fraction (0.09–4 mm), milled to powder and treated with H2O2. The thermal energy released upon sulphide oxidation was optically detected and temperatures measured using a portable infrared thermographic camera. Based on temperature–time progression curves, the oxidation reactivity of sulphides was derived from high to low: chalcopyrite > arsenopyrite > pyrite > sphalerite > stibnite > galena, which depends on grain size, amount of sulphides and other non-sulphide mineral phases present in the sample material. The study demonstrates that the application of H2O2 to sulphide sample powders and subsequent visualisation of the treated materials using a thermographic camera represents a rapid technique in revealing the presence of oxidising sulphides under all pH conditions.

Quantitative X-ray µCT Measurement of the Effect of Ore Characteristics on Non-Surface Mineral Grain Leaching

In heap (bio)leaching processes, a substantial fraction of the valuable mineral is positioned below the ore particle surface. X-ray micro-computed tomography (μCT) was used to quantify the effect of ore type and structure and operating temperature on the leaching of this mineral, to investigate the rate-controlling factors. Mini-leaching columns containing agglomerated chalcopyrite, pyrite, and malachite ores were scanned by X-ray μCT (13.40 µm resolution) at select time intervals. The leaching of a relatively porous malachite ore was reaction-controlled, with no leaching penetration limitation into the ore particles. For two less porous ore types, the structure and higher porosity of the agglomerate rim and conditions that resulted in the degradation of the full ore matrix structure were found to be the determining variables of the leaching extent and time. In the case of a chalcopyrite ore, an enhancement of copper recovery and sulphide mineral dissolution with increasing temperature was attributable to the increased leaching penetration distance and crack development in addition to thermodynamically expected increased leaching rate. Increasing temperature did not affect the maximum penetration distance for the waste rock containing pyrite, with no crack development observed. Overall increases in iron recovery were due to accelerated leaching rates, though diffusion or mineral access limitations were evident at a higher temperature.