Real Ore Research Articles

Application and electrochemical depression mechanism of sodium sulfite on the flotation separation of galena–pyrite mixed concentrate in Yiliang typical high‑sulfur lead–zinc deposit

The high content of pyrite in high‑sulfur lead–zinc sulfide resources affects the electrochemical properties and floatability of galena and sphalerite, which results in difficult flotation separation. In this study, the negative effects of a high-alkaline process were weakened by introducing an efficient mixed depressant CaO + Na2SO3 in selective flotation separation of galena from pyrite. Flotation separation tests of real ore samples showed that the mixed depressant was more efficient than single CaO (5000 g/t), and the best process conditions of Pb grade 64.01 % and Pb recovery 88.45 % were obtained. The effects of Na2SO3 on the electrochemical interaction between the two minerals were studied by micro-flotation tests, electrochemical, ion dissolution, UV–Vis measurements, zeta potential measurements, and X-ray photoelectron spectroscopy (XPS) detections. Results indicated that Na2SO3 could weaken the galvanic interaction between galena–pyrite and reduce the Pb2+ dissolution from the galena surface. Na2SO3 could desorb the collector ethyl xanthate pre-adsorbed on the pyrite surface.

Integration of stability factors A, B and C on the Mathews Stability Graph into a mining-level optimization algorithm

Purpose. This study aims to enhance the optimization approach by integrating stability analysis using Mathews Stability Graph into stope mining-level optimization algorithm. Methods. The programming language is employed to integrate the Mathews Stability Graph into the stope mining-level optimization algorithm at the preliminary optimization stage, providing dimensional constraints based on rock conditions. Algorithm validation is conducted using three scenarios reflecting rock conditions in the block model: fixed stope dimensions with a maxi-mum stope size, fixed stope dimensions with a minimum stope size, and variable stope dimensions based on the proposed algorithm. Additionally, to validate the stability of the stope in the optimization algorithm, the stability of each stope wall is confirmed by back plotting on a stability graph. Findings. The algorithm manages to create a stope design that complies both with geotechnical and economic aspects, based on the data provided in the synthetic block model. Originality. Optimal stope design is often determined by the stope’s economic parameter, whereas geotechnical variables, easily available in the block model, are neglected. The proposed algorithm aims to include stability analysis using the Mathews Stability Graph into the stope mining-level optimization algorithm. Practical implications. The method was successfully tested using data from a block model simulating the conditions of a real ore body in Indonesia. In addition, the method may be used by mine planners during the early stage of feasibility assessment.

Industry relevant microfluidic platforms for mineral leaching experiments

Microfluidic and lab-on-a-chip devices offer exquisite temporal and spatial control over chemical and physical processes that are important in mineral exploration and mining. These include mineral-water interfacial reactions, dissolution, and adsorption/desorption in pores, fractures, or other micro/nanostructures. Microfluidic mineral studies offer advantages of small sample and reagent volumes, high throughout, and short analytical cycles that may enable in-field mining decisions. However, not many microfluidic studies have targeted these mining sector challenges for mineral leaching. In this review, special attention is given to microscale experimental platforms for predicting extraction and leaching of industrially-relevant samples (real ore samples). Advantages and challenges of these platforms are given. The review concludes that there are significant opportunities for microfluidics in mineral analysis, screening, process intensification, and process control in the resource and minerals sector.

Study on the selective separation mechanism of tannin acid in chalcopyrite and talc: Insights from adsorption morphology and electrochemical analysis

A key strategy for achieving the selective separation of talc and chalcopyrite is the development of chemical depressants with high solubility and strong selectivity. Tannic acid (TA), a polyphenol found in green plants and has good solubility, contains abundant phenolic hydroxyl groups. Moreover, the adsorption mechanism of TA with chalcopyrite and talc was examined after TA was chosen as the separation depressant for chalcopyrite and talc. Single-mineral flotation test results found that at optimal pH and TA and sodium butyl xanthate (SBX) dosages, the flotation recoveries of talc and chalcopyrite were 9% and 92.17%, respectively, and the difference in recovery between them was 83.17%. Results from real ores and artificially mixed minerals tests also confirmed that TA can achieve selective separation of chalcopyrite and talc. Since chalcopyrite has distinct electrochemical properties, the results of atomic force microscope and electrochemical tests demonstrated that there are significant differences in the adsorption behavior of TA on the surface of chalcopyrite and talc. And the adsorption selectivity of SBX on the chalcopyrite surface is better than that of TA on the chalcopyrite surface, which is an important reason for the selective separation of chalcopyrite and talc.

ConGCNet: Convex geometric constructive neural network for Industrial Internet of Things

The intersection of the Industrial Internet of Things (IIoT) and artificial intelligence (AI) has garnered ever-increasing attention and research interest. Nevertheless, the dilemma between the strict resource-constrained nature of IIoT devices and the extensive resource demands of AI has not yet been fully addressed with a comprehensive solution. Taking advantage of the lightweight constructive neural network (LightGCNet) in developing fast learner models for IIoT, a convex geometric constructive neural network with a low-complexity control strategy, namely, ConGCNet, is proposed in this article via convex optimization and matrix theory, which enhances the convergence rate and reduces the computational consumption in comparison with LightGCNet. Firstly, a low-complexity control strategy is proposed to reduce the computational consumption during the hidden parameters training process. Secondly, a novel output weights evaluated method based on convex optimization is proposed to guarantee the convergence rate. Finally, the universal approximation property of ConGCNet is proved by the low-complexity control strategy and convex output weights evaluated method. Simulation results, including four benchmark datasets and the real-world ore grinding process, demonstrate that ConGCNet effectively reduces computational consumption in the modelling process and improves the model’s convergence rate.

Novel approach to locate micro-scale mineral regions of interest in real ores

The surface of minerals plays a pivotal role throughout the process of mineral beneficiation and utilization. Studies on surface properties, such as surface chemistries, of mineral phases of interest in real ores enable the selective separation of minerals, thereby enhancing the utilization of mineral resources. Nevertheless, obtaining specific mineral phases, especially for finely disseminated or poorly crystalized minerals, from real ores without altering their surface chemistries remains a challenge. The challenge also persists in investigating the same micro-scale mineral region in real ores using various surface characterization techniques, such as scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). This paper proposes a novel approach and procedures for locating micro-scale mineral regions of interest in real ores based on a three-dimensional coordinate system etched onto the ore surface using laser etching technology. A copper-nickel ore from Jinchuan, China, served as an illustrative example, with the finely disseminated chalcopyrite and pentlandite regions in the real ore sample being located and investigated using SEM and XPS. The approach presented in this study enables the in-situ detection of surface chemistries of specific mineral phase in real ores, ensuring the homogeneity and in-situ nature of the obtained surface chemistry data. This approach holds considerable promise, especially in the investigation of surface chemistries of minerals with fine dissemination and poor crystallization.

Application and depression mechanism of sodium humate on flotation separation of molybdenite and pyrite

ABSTRACT The depression of pyrite in the flotation separation of molybdenum-sulfur (Mo-S) mixed concentrate has become a significant issue. This study aimed to examine the process of separating molybdenite and pyrite in the presence of sodium humate (NaHA). The results of micro-flotation tests indicated that NaHA exhibited significant pyrite depression capabilities and displayed remarkable selectivity toward both pyrite and molybdenite. Real ore flotation experiments have shown that adding 22.5 mg/L of NaHA to the pulp of Mo-S mixed concentrate at a pH of 6.5, the flotation indexes achieved 46.01% Mo grade and 90.11% Mo recovery. It is noteworthy that the dosage of NaHA was significantly lower compared to the 505 utilized in the mineral processing plant. Contact angle measurements revealed that NaHA effectively increased the surface hydrophilicity of pyrite. Adsorption amount measurements, zeta potential measurements, and Fourier infrared spectroscopic (FT-IR) analysis indicated that the adsorption capacity of NaHA on pyrite was higher than on molybdenite. NaHA had a highly selective inhibitory capacity for Mo-S mixed concentrate and is an ideal separation depressant.

Flotation separation mechanism of malachite from calcite using the pentyl xanthate as the collector

Calcite is a commonly associated gangue mineral in oxidized copper ore, while the flotation separation of oxidized copper ore from calcite is a bottleneck technology in the utilization of carbonate-type oxidized copper ore. The present study applied the pentyl xanthate (PX) as a collector to efficiently separate malachite and calcite without any other reagents. The flotation results indicate that the PX dosage is a key factor determining the flotation separation results of malachite and calcite. When its dosage reaches 1000 mg/L, the flotation recovery rate of malachite can reach 88.7 %, while calcite is less than 5 %. The flotation test of real ore contained these two minerals further confirmed that the malachite could be separated from calcite using PX as the collector. The mechanism and characterization analysis show that the selective substitution reaction between xanthate ions and OH ions on the malachite surface could generate hydrophobic substances of copper xanthate, which largely improves the hydrophobicity of the malachite surface. This study is expected to provide theoretical and practical assistance for the efficient flotation beneficiation of low-grade marble-type copper oxide ore.

Efficient flotation separation of picromerite and halite by a novel collector of sodium dodecyl benzene sulfonate

Common reverse flotation is difficult to separate efficiently picromerite with a high halite content. This work employed direct flotation to separate picromerite and halite, using sodium dodecyl benzene sulfonate (SDBS) as a novel picromerite collector. The flotation performances were evaluated by single and real ore flotation tests, with results indicating that K+ recovery was 95.89%, while Na+ content was less than 2% in the concentrate at an SDBS dosage of 200 g/t, which suggested SDBS was an effective picromerite collector with excellent separation performance. The interaction mechanism was investigated by adsorption experiment, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope and Energy Dispersive Spectrometer (SEM-EDS), and X-ray Photoelectron Spectroscopy (XPS) analysis. The adsorption experiments demonstrated that picromerite had a stronger affinity to SDBS than halite, confirming that SDBS exhibited good selectivity in the flotation of picromerite and halite. FTIR and SEM-EDS analysis revealed that SDBS adsorbed on the picromerite surface. XPS results further unveiled that SDBS chemisorbed on the picromerite surface through the strong complexation between sulfonic acid groups and Mg atoms on the picromerite surface, forming O-Mg bonds. This study provides a new perspective on the efficient separation of picromerite and halite, facilitating a high production efficiency of picromerite.

Improving xanthate flotation of fine pyrite using SPAM and the mechanism

ABSTRACT This paper focuses on the promotion mechanism of sulfonated polyacrylamide (SPAM) on SBX flotation performance on fine pyrite, and verifies the positive effect for a gold ore with pyrite as the main Au-bearing mineral. Micro flotation showed that fine pyrite (−26 + 15 μm) floated poorly compared with coarser ones (−74 + 38 μm), and this cannot be completely filled through increasing the SBX dosage; however, by adding moderate SPAM into the pulp after SBX the flotation of fine pyrite was obviously improved. The real ore flotation revealed that SPAM decreased total reagent dosage and improvement on the concentrate indexes. SBX/SPAM system enabled faster settlement of fine pyrite compared with only SBX or SPAM system, indicating that larger particle size was obtained through hydrophobic and bridging flocculation. Zeta potential results showed that the pre-adsorbed SBX had little effect on the further adsorption of SPAM. Contact angle measurements suggested that the addition of moderate SPAM (50 μg/L) had almost no effect on pyrite surface hydrophobicity, illustrating that SPAM just bridged different fine particles adsorbed SBX rather that covered them. FTIR results showed that the amount of SPAM participating in bridging action was few.

Ethylenediamine tetramethylenephosphonic acid as a selective collector for the improved separation of chalcopyrite against pyrite at low alkalinity

Chalcopyrite is the main Cu-containing mineral and cannot be separated well from pyrite using traditional xanthate collectors with large amounts of lime depressant, resulting in difficulties of the tailing treatment and associated precious metals recovery. Therefore, in this study, the green and odourless ethylenediamine tetramethylenephosphonic acid (EDTMPA) was introduced as a novel chalcopyrite collector. Flotation results from the binary mineral mixture and real ore demonstrated that EDTMPA could realize the selective separation of chalcopyrite from pyrite relative to ethyl xanthate (EX) without any depressants within the wide pH range of 6.0–11.0, and might replace the traditional high-alkaline lime process. Electrochemical and Fourier transform infrared spectra measurements indicated that the difference in adsorption performance of EDTMPA on chalcopyrite and pyrite was larger than that of EX, suggesting a better selectivity for EDTMPA. Density functional theory calculations demonstrated that there were stronger chemical bonds between P—O groups of EDTMPA and the Fe/Cu atoms on chalcopyrite in the form of a stable six-membered ring. Crystal chemistry calculations further revealed that the activity of metal atoms of chalcopyrite was higher than that of pyrite. Therefore, these basic theoretical results and practical application provide a guidance for the industrial application of EDTMPA in chalcopyrite flotation.

Desorption and Reuse of Pb-BHA-NaOL Collector in Scheelite Flotation

Pb and BHA in Pb-BHA-NaOL collector assembled by lead nitrate (Pb), benzohydroxamic acid (BHA), and sodium oleate (NaOL) with a 240:120:1 molar ratio in scheelite flotation have the common defects of flotation reagents including high cost, environmental pollution and reducing hydrometallurgy efficiency. Therefore, in this study, the efficient desorption and reuse of Pb and BHA adsorbed on the scheelite surfaces was first proposed. The desorption test results showed that 80.71% Pb and 70.93% BHA could be efficiently desorbed from the scheelite concentrate surfaces through strong stirring for 15 min at pH 13.0 and a speed of 1600 r/min. The reuse of the desorbed collector could save 67% Pb and 75% BHA. The results of desorption and reuse tests of the real ore also exhibited high feasibility in industrial application. Fourier transform infrared spectroscopy analysis revealed that Pb-O, C=O, and C-N groups of Pb and BHA adsorbed on the scheelite surfaces obviously weakened or disappeared. Atomic force microscopy analysis further confirmed that most of the Pb and BHA on the scheelite surfaces were removed. Therefore, this work not only solves the above defects of the collector but also provides a reference for the desorption and reuse of other flotation reagents.

Selective Heavy Atom Effect-Promoted Photosensitization Colorimetric Detection of Ag+ in Silver Ore Samples

Analytical methods capable of facile screening of silver ore samples are of vital importance for resource exploration and ore mining. Due to its extreme simplicity, colorimetric detection is desired for silver ore screening, but the analytical sensitivity of existing approaches is typically not sufficient. Here, an Ag+-selective heavy atom effect-promoted photosensitization colorimetric assay was developed. Specifically, Ag+ and dsDNA-staining dye (photosensitizer) were spatially adjoined in close proximity in dsDNA bearing several cytosine (C) mismatches, leading to enhanced 1O2 generation for photosensitized oxidation of chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB). Due to the stable C-Ag(I)-C metallo-base pair, the C-C mismatches in dsDNA can selectively capture Ag+, thus allowing highly selective colorimetric detection of Ag+ with a visual limit of quantification (LOQ) as low as 0.2 ng/mL. For ore sample analysis, the visual LOQ was about 2 g/t, which was suitable for colorimetric screening analysis of ores of different values. The accuracy of the proposed method was verified through analyzing both certified reference material and real ore samples, the results of which agreed well with those obtained by electrothermal atomic absorption spectrometry (ET-AAS). To facilitate field silver ore screening, acid leaching of the samples was also adopted, and satisfactory analytical accuracy was also obtained at a rough leaching efficiency of 20%.

球面調和関数－主成分分析による粒子形状生成と個別要素法への適用

In various fields, most raw materials are in a granular state: their bulk properties are therefore of interest. The discrete element method (DEM) is frequently used to determine these properties. As numerous particles can be simulated by DEM, and particle shapes affect bulk properties, effective modeling of realistic particle shapes is required. In this study, two types of DEM simulations were compared: one using real ore particle shape, and one using particle shape computed by spherical harmonic-based principal component analysis. We confirmed the latter to successfully reproduce the bulk properties (repose angle, porosity, and coordination number) of the former.

Reducing the adhesion of mica on arsenopyrite surface using sodium phytate and the application in flotation separation

ABSTRACT The adhesion of clay minerals into sulfides concentrate is one of the key problems of mineral processing industry. In this study, sodium phytate (SP) was used as a dispersant in mixed mica and arsenopyrite system. The addition of mica affected the rheological property of arsenopyrite pulp, and this effect could be mostly reduced after the addition of SP. The reflection polarizing microscope results confirmed the adhesion behavior of mica with arsenopyrite to form the aggregate structure; and the addition of SP could disperse them from each other, which is regarded as advantageous to the flotation separation. Adsorption test results revealed that the SP molecules selectively adsorbed onto mica surface. XPS results showed that the P-O groups in SP anions mainly adsorbed with the Al active sites on mica surface, resulting in the greater electrostatic repulsion between mica particles, mica and arsenopyrite particles. This is the mechanism for mica/arsenopyrite dispersion. In flotation tests, SP exhibited well performance in increasing the flotation indexes. A 6 × 10−5mol/L of SP enlarged the recovery difference between arsenopyrite and mica from 19% to 60.0%. In real ore flotation, it also showed better performance regardless compared with the system without dispersant or with traditional dispersant SHMP.

Selective flotation separation of magnesite from dolomite and calcite using the mixed WG + HEDP depressants

The decalcification of magnesite remains a difficult subject in mineral flotation. In this work, water glass and HEDP (1-hydroxyethylene-1,1-diphosphonic acid, expressed as WG + HEDP) were performed as the mixed depressants in magnesite-dolomite-calcite flotation separation. Micro-flotation test was conducted to study the inhibition effect of the mixed depressants, it indicated that 20 mg/L water glass and 15 mg/L HEDP were the optimal dosages because of the maximum differences in flotation recoveries. The inhibition mechanism of the mixed depressants was revealed by ways of zeta potential measurement, contact angle test and X-ray photoelectron spectroscopy (XPS) test. It could be concluded that WG + HEDP could co-adsorb on minerals surface, but they co-adsorbed stronger on dolomite and calcite surface than magnesite. Furthermore, sodium oleate (NaOL) could further adsorb on magnesite but not dolomite and calcite surface, resulting in the differences in wettability and floatability of minerals. At last, the real ore experiment confirmed the effectiveness of WG + HEDP on magnesite flotation.

Identification of Valuable Minerals or Metals in Ores Using Microwave Imaging

This study investigates the potential application of microwave imaging (MWI) in ore sorting systems for mineral processing. Modern sensor-based ore sorting employs various sensing methods, such as X-ray transmission (XRT), X-ray fluorescence (XRF), optical sensing, and inductive sensing. We aim to apply MWI techniques in sensor-based ore sorting to separate ore particles containing valuable minerals or metals from barren particles. Compared to existing ore sensing methods, MWI has the potential to penetrate deeper into rock particles and to be used as a supplementary method for analyzing those ores with high contrast in electromagnetic (EM) properties between valuable minerals/metals and gangue minerals. Microwave scattering simulations are performed on realistic ore models. Measurements on real ore samples are also conducted. The confocal microwave imaging (CMI) algorithm is used for image formation. The simulation and measurement results both successfully identify the presence of valuable minerals or metals in ores, thereby demonstrating the feasibility of applying MWI in ore sorting.

A novel electrooxidation vapor generation technique for the direct analysis of trace Os in ore/water samples

All electrolytic vapor generation technologies are based on cathodic reduction, but this paper focuses on how to use anodic oxidation to realize the gaseous transformation of noble metal Os. Supported by RuO2-based dimensionally stable anode (DSA), we found that the conversion from trivalent/tetravalent Os to the OsO4 can be carried out continuously and stably, even at the μg L−1 level. Interestingly, there was a negative correlation between the conversion of OsO4 and the RuO2 content in the DSA. The decrease of oxygen absorption potential and the increase of current density suggest that the oxidation process of Os belongs to electrocatalytic behavior. The catalytic activity of the material has an obvious influence on the conversion of osmium while the formation of free radical may be crucial for the effective oxidation. Under the optimum conditions, this electrocatalytic synthesis of OsO4 combined with ICP-MS can realize the same effect of oxidation and detection of two osmium species [Os(III) and Os(IV)]. The proposed method exhibits a low limit of detection (5 pg kg−1), a wide linear range (0.1–100 μg L−1) and excellent anti-interference performance, which promotes the direct analysis of total Os in real ore samples without separation. Considering the catalytic activity of OsO4 in specific reactions, this green anodic electrosynthesis technology is also expected to provide more possibilities.

Enhanced flotation of chalcopyrite particles by grinding with short cylinder media

In mineral processing, sufficiently liberated target minerals by grinding is a prerequisite for successful flotation. Rod grinding produces particles with a narrower size range and better floatability through line contacts, but with a lower production capacity compared to balls (point contacts). As a result, balls remain as the preferred media for most dressing plants. However, balls produce many ultra-coarse and ultra-fine particles. Hence, grinding media with multiple contact forms could offer a compromise, which can combine the advantages of both rods and balls. In this paper, the performance of short cylinders which comminute minerals in point and line contact modes and ball grinding media were compared and evaluated using chalcopyrite as a test mineral. The grinding results show that short cylinders generate more angular particles with intermediate particle sizes and have a higher grinding efficiency compared with balls. Short cylinders selectively produce more active {112} surfaces of chalcopyrite, which possess higher adsorption capacity with collectors and were preferentially floated as the concentrate. Flotation tests confirm that the real ore particles ground by short cylinders have higher liberation degree and exhibit a higher flotation recovery of chalcopyrite than ore ground using balls. This study provides a reference scheme for the grinding and flotation optimization of valuable minerals.

Interaction mechanism of a novel reagent scheme in the selective separation of scheelite from calcite

Up to now, the selective separation of scheelite and calcite is still tricky. Etidronic acid (abbreviated as EA or H4L) is an environmental scale inhibitor capable of chelating metal ions. This research adopted the EA as a selective depressant to separate scheelite from calcite. Flotation results of the single mineral, binary mixed minerals, and real ore showed that EA had better selectivity for calcite at pH 10.0 with sodium oleate (NaOL) as a collector. Zeta potential results found that EA adsorption amount on the positively charged calcite surfaces was more significant than that on the negatively charged scheelite surfaces. X-ray photoelectron spectroscopy, solution chemistry, and density functional theory (DFT) calculation further proved that on calcite, the active O atoms in the dominant species (HL3-) of EA had a strong chemical interaction with Ca sites to form a hydrophilic Ca–EA complex by O 2 s and Ca 3p orbitals hybrid. In contrast, the interaction with these on scheelite was significantly weaker. Afterward, NaOL tended to occupy the scheelite surfaces due to its higher activity of Ca rather than the calcite surfaces. Therefore, the difference in HL3- and OL- adsorption on both minerals achieved the selective separation of scheelite and calcite.