Search Results (13)

With the increasing demand for nickel, relentless efforts have been made to find alternative and highly selective collectors for recovering pentlandite. This study employed density functional theory (DFT) with dispersion correction to examine the interactions of iron-rich pentlandite (Fe₅Ni₄S₈) mineral surface with various collectors: S-allyl-N-diethyl-dithiocarbamate (ADEDTC), O-isopropyl-N-diethyl-thionocarbamate (IPDETC), sodium mercaptobenzothiazole (SMBT), and sodium-2,6-dithio-4-butylamino-1,3,5-triazine (SDTBAT). The plane surface of (311) proved to be the most stable surface with a surface energy of 1.48 J.m⁻², aligning well with the experimental X-ray diffraction (XRD) results and morphology. Adsorption simulations were performed on both Ni and Fe atoms of the plane surface of (311). ADEDTC exhibited the most exothermic adsorption energy of −460.58 kJ.mol⁻¹, compared to SMBT (−249.59 kJ.mol⁻¹), IPDETC (−161.01 kJ.mol⁻¹), and SDTBAT (−352.48 kJ.mol⁻¹). The adsorption strengths followed the order ADEDTC > SMBT > SDTBAT > IPDETC. Importantly, these collectors showed a preferential adsorption on the Ni atoms over Fe atoms, indicating selectivity towards Ni sites on the pentlandite mineral surface. These findings suggested that ADEDTC was the most effective collector for flotation applications involving pentlandite. As such, ADEDTC could potentially replace commonly used collectors or be used as a co-collector in the recovery of pentlandite minerals. Full article

Copper polymetallic sulfide ore from the Asgat copper polymetallic deposit in Mongolia has been found to contain a high grade of antimony and silver in addition to copper. In this research, flotation experiments using sodium butyl xanthate (SBX), ammonium dibutyl dithiophosphate (ADD), isopropyl ethyl thionocarbamate (Z-200), and their mixtures were conducted on a sample from the deposit under natural pH conditions. The results of the flotation tests indicate that optimal conditions were achieved with a feeding of 92% −0.074 mm (92% finer than 0.074 mm), sodium silicate dosage of 800 g/t, sodium humate dosage of 300 g/t, sodium sulfite dosage of 300 g/t, and collectors of 60 g/t of ADD and 60 g/t of Z-200. The closed-circuit flotation tests showed that the recovery of copper, antimony, and silver from the ADD/Z-200 combination was 8.13%, 5.41%, and 9.26% higher than that form the single Z-200 while reducing the reagent cost by 12.75%. Full article

To reduce lead content in copper concentrates, this study developed a novel galena depressant, TA (thioureidoacetic acid). This study utilizes a synthetic mineral feed with fully liberated galena and chalcopyrite from separate sources to establish baseline separation conditions. The adsorption capability of TA on galena surfaces was systematically investigated through micro-flotation tests, surface characterization, and first-principles calculations. Results demonstrate that TA effectively reduces galena recovery (from 82.92% to 12.29%) without compromising chalcopyrite flotation efficiency (>83.2% recovery) when using thionocarbamate (Z200) as the collector. FTIR and XPS analyses confirm that TA chemisorbs onto galena surfaces via its C=S and C=O functional groups. First-principles calculations reveal dual Pb-S and Pb-O bond formation during TA adsorption, resulting in stronger interfacial binding energy compared to Z200. This work establishes a molecular engineering framework for designing high-selectivity depressants. Full article

Ester collectors have rapidly developed into the main flotation collectors for copper sulfide minerals since they were developed. In this study, the collecting performance of four collectors, O-isopropyl-N-ethyl thionocarbamate ester (IPETC), 3-pentyl xanthate acrylate ester (PXA), O-isobutyl-N-allyl-thionocarbamate (IBALTC), and O-isobutyl-N-isobutoxycarbonyl-thionocarbamate (IBIBCTC), was investigated through microflotation tests, microcalorimetric measurements, and quantum chemical calculations. The results of the microflotation tests show that IBALTC and IPETC have stronger collecting abilities than IBIBCTC and PXA; the order of collecting ability is IBALTC > IPETC > IBIBCTC > PXA. The microcalorimetry test also shows that the adsorption heat of the former two is higher. Quantum chemical calculations show the energy difference between the HOMOs of the collector and the LUMOs of minerals. The electrostatic potential extremum around S atom and the first ionization potential of IPETC and IBALTC are similar and were smaller than IBIBCTC and PXA, which shows that the collecting ability of the former two is similar and stronger than the latter two. Among the collectors, the S atom polarizability, electrophilic, and nucleophilic attack index of IBALTC are the largest, indicating that its electronic deformation capability and nucleophilic properties are the strongest, which results in the strongest coordination interaction with the copper ions in copper sulfide minerals and thus the highest collecting ability. The S atom polarizability, electrophilic, and nucleophilic attack index of PXA are the smallest, indicating that its electronic deformation capability and nucleophilicity are the weakest, and its collecting ability is the weakest. The coordination between collector and mineral surface was analyzed theoretically. The research results are of great help to the design and development of ester collectors. Full article

The search for effective reagents for the flotation of non-ferrous metals from mineral raw materials is an actual problem. The article discusses the results of research on improving the technology of processing copper–molybdenum ores using a combined collector emulsion. The object of research was copper–molybdenum ore containing 0.43% copper and 0.0089% molybdenum. Copper minerals are represented by chalcopyrite 1.2% and chalcocite 0.015%, while covellite is present in a much smaller amount. The main mineral of molybdenum is molybdenite. The cycle of collective copper–molybdenum flotation includes the main flotation, control flotation, and three re-cleanings of concentrate. In the basic mode, the collective Cu–Mo concentrate was produced with the copper content of 16.25% with an extraction of 77.79% and with the molybdenum content of 0.45% with an extraction of 79.38%. Reaflot, thionocarbamate, and butyl xanthate were used in a ratio of 1:3:15 to prepare a combined collector agent. In order to produce the combined collector emulsion, the best degree of dispersion, which amounted to 99.5% of particles with a size of −3.6 μm, was chosen. During the Cu–Mo ore flotation using an optimally dispersed microemulsion of the combined collector agent, a collective Cu–Mo concentrate was obtained with a copper content of 18.2% with an extraction of 83.58%, and with a molybdenum content of 0.49% with an extraction of 88.46%. The use of a combined collector agent increases the extraction of copper into the collective Cu–Mo concentrate by 5.79%, while the extraction of molybdenum increases by 9.08%. Full article

Thionocarbamates are the group of collectors that are mostly used for flotation of sulphide copper minerals, alone or in combination with xanthates depending on a mineralogical composition of the ore. In this paper, the results of the study of application of thionocarbamates in copper slag flotation are presented. Chemical analysis of smelter slag sample obtained from Flotation plant in Bor, Serbia, showed that it contains 3.56% of copper, of which over 73% is in the sulphide form, as well as 0.58 g/t of gold and 11.30 g/t of silver. XRD analysis identified fayalite and magnetite as main minerals present in the slag and SEM-EDS analysis showed that copper is mainly present in the form of sulphide minerals, thus making it suitable for flotation with thionocarbamates. Two thionocarbamates MX 980 and TC 1000 and one xanthate SIPX, along with their mixtures MX 980 + SIPX and TC 1000 + SIPX, were investigated. The influence of parameters such as collector type and dosage, grinding fineness, pulps’ pH and flotation time, on flotation indicators (recovery, yield and copper grade in concentrate) were determined. Smaller dosages of thionocarbamates (40 g/t) provided concentrates with high copper grades, 22.34% (MX 980) and 18.42% (TC 1000) and lower recovery rates, 83.98% (MX 980) and 87.78% (TC 1000), while the increase of dosages to 200 g/t led to the increase of recovery rates for more than 4% and a significant decrease in copper grades. The increase of grinding fineness from 50% to 70% of grain size < 0.074 mm showed a positive impact on flotation indicators, recovery rate, copper grade and yield, for all investigated collectors and their mixtures, while, with the further increase from 70% to 90%, recovery rates continued to increase while copper grades decreased. The increase of pulps’ pH had a positive influence, especially for MX 980, for which recovery rates increased with the increase of pH from 8 to 10 (12). A flotation kinetics test showed that flotation with TC 1000 was the fastest, i.e., recovery rate after 20 min of flotation was over 91%, while recoveries obtained with other collectors were a few percentage points lower. Full article

A comprehensive recovery process for the selective separation and enrichment of copper, zinc and iron minerals from a polymetallic ore was developed, which consisted of copper flotation, zinc flotation, and iron magnetic separation, and the adsorption mechanism of the copper collector Z-200 (O-isopropyl-N-ethyl thionocarbamate) was also studied in this work. The contents of the main valuable metallic elements of Cu, Zn and Fe in the ore were respectively 0.61%, 1.68% and 14.17%, and they mainly existed as chalcopyrite, sphalerite and magnetite, whose dissemination relationship was complex. Under the optimal conditions of this process, the recoveries of Cu, Zn and Fe in their respective concentrates reached 86.1%, 87.6% and 77.8%, and their grades were separately 20.31%, 45.97% and 63.39%. This process realized the selective separation and beneficiation of copper, zinc, and iron minerals from the ore, and had promising industrial application prospects. The adsorption configuration analysis demonstrated that the steadiest adsorption configurations of Z-200 on the surfaces of chalcopyrite, sphalerite and magnetite were the simultaneous adsorption of carbonyl S together with the O atom. Compared with sphalerite and magnetite, Z-200 was more prone to adsorb on the chalcopyrite surface. The Mulliken charge population and bond length analyses manifested that Z-200 chemically adsorbed on the chalcopyrite surface by forming a normal covalent bond and a back donation covalent bond, and the normal covalent bond played a leading role. The chemisorption of Z-00 was supported by the FTIR spectrum analysis result. Full article

In the present study we tested, using the microscale thermophoresis technique, a small library of thionocarbamates, thiolocarbamates, sulfide and disulfide as potential lead compounds for SARS-CoV-2 Mpro drug design. The successfully identified binder is a representative of the thionocarbamates group with a high potential for future modifications aiming for higher affinity and solubility. The experimental analysis was extended by computational studies that show insufficient accuracy of the simplest and widely applied approaches and underline the necessity of applying more advanced methods to properly evaluate the affinity of potential SARS-CoV-2 Mpro binders. Full article

O-isopropyl-N-ethyl thionocarbamate (IPETC) collector was used to selectively recover elemental sulfur from a high-sulfur residue, and its flotation performance, structure–property relationship and adsorption mechanism to elemental sulfur were studied. The raw ore flotation test showed that IPETC displayed superior flotation performance to the elemental sulfur compared with sodium ethyl xanthate (SEX) and ammonium dibutyl dithiophosphate (ADDTP) collectors. Pure mineral flotation and adsorption experiments further demonstrated that among the three collectors, IPETC had the strongest collecting power and the optimum selectivity towards elemental sulfur. The structure–property relationship research based on density functional theory (DFT) calculation supported the above conclusion. The adsorption mechanism analysis manifested that IPETC adsorption on elemental sulfur surface was a chemical process by separately generating normal covalent bond between carbonyl S atom and S atom and a backdonation covalent bond between O atom and S atom, which was confirmed by the FTIR spectrum analysis result. IPETC exhibits excellent collecting ability and selectivity for elemental sulfur and therefore it has bright application prospects. Full article

Norway has newly seen an upsurge of interest in exploiting its mineral deposits influenced by fresh Government focus and survey support for previously under-prospected areas. One of the major areas of interest is a huge copper deposit, operated by Nussir ASA, located in the Repparfjord tectonic window in the Caledonides of west Finnmark. The latest mineral resource estimation is from July 2014, which states that Nussir consists of 5.8 million tonnes of indicated resources and 60.2 million tonnes of inferred resources, giving 66 million tonnes of copper ore. This paper represents the first study on processing characteristics of this ore to date. Our parallel studies using xanthates and dithiophosphates as collectors for Nussir ore flotation examined the grade and recovery of copper, silver, gold, and platinum group (PGM) minerals. Therefore, in this subsequent study, a chelating agent n-Butoxycarbonyl-O-n-butyl thionocarbamate (BBT) is used as a collector and it was found that the recovery and grades of the economically interesting minerals are improved at as low as 2 × 10⁻⁵ M collector concentration. Zeta potential, Hallimond flotation and adsorption studies were initially performed in order to assess the selective interaction of BBT and its blend with SIBX (Sodium Isobutyl xanthate) on the three copper minerals of the ore. The bench scale flotation experiments were performed using mixtures of xanthate and thionocarbamate collectors of the Nussir ore and both the resulting copper recovery and grade employing these collector mixtures is observed to be 2–8% superior to the use of a single collector system. Additionally, the current study revealed that the metallurgical results are strongly influenced by the ratio of the collectors in the mixture and particularly the sequence of the collector addition. Full article

Ozonation at a high O₃ dosage can achieve high efficiencies in removing flotation reagents but it has a low ozone-utilization rate. The ozonation of potentially toxic thiol collectors (potassium ethyl xanthate (EX), sodium diethyl dithiocarbamate (SN-9), O-isopropyl-N-ethyl thionocarbamate (Z-200) and dianilino dithiophoshoric acid (DDA)) was investigated in an ozone-bubbled reactor at a low O₃ dosage of 1.125 mg/(min·L). The degradation kinetics, mineralization, ozone utilization, changes of biodegradability, and water quality parameters were studied, and the degradation behaviors of four collectors were compared. Thiol collectors could be effectively degraded with a removal ratio of >90% and a mineralization ratio of 10‒27%, at a low O₃ dosage. The ozonation of thiol collectors followed the pseudo first-order kinetics, and rate constants had the order of k_SN-9 > k_EX > k_Z-200 > k_DDA. The Z-200 and DDA were the refractory flotation reagents treated in the ozonation process. After ozonation, the biodegradability of EX, SN-9, and DDA solutions was remarkably raised, but the biodegradability of Z-200 only increased from 0.088 to 0.15, indicating that the Z-200 and its intermediates were biologically persistent organics. After ozonation, the solution pH decreased from 10.0 to 8.0‒9.0, and both the conductivity and oxidation-reduction potential increased. The ozone utilization ratio in decomposing thiol collectors was above 98.41%, revealing almost complete usage of input O₃. The results revealed that thiol collectors could be effectively degraded by O₃, even at a low dosage, but their degradation behaviors were quite different, due to intrinsic molecular properties. Full article

Copper and lead are two important and widely used metals in industry. Chalcopyrite (CuFeS₂) is associated with galena (PbS) in ore, and it has been a research hotspot in separating galena from chalcopyrite by flotation. In this study, the flotation behaviors of chalcopyrite and galena were studied through flotation tests, adsorption measurements, solution chemistry calculation, Fourier transform infrared spectroscopy (FTIR) and molecular dynamics (MD) simulations. The results show that the floatability of chalcopyrite is better than that of galena in the presence of O-isopropyl-N-ethyl thionocarbamate (IPETC), and the recovery difference between chalcopyrite and galena is about 20% when IPETC is 7 × 10⁻⁴ mol/L at pH 9.5, while the floatability difference between the two minerals is significant. Competitive adsorption of OH⁻ and IPETC on mineral surfaces leads to lower floatability of galena than that of chalcopyrite. IPETC is able to remove the hydration layer on mineral surfaces and then adsorb on active sites. The floatability of minerals is enhanced with the increase of their hydrophobicity. This study provides a reference to separate galena from chalcopyrite. Full article

Novel ether thionocarbamates, O-butoxy isopropyl-N-ethoxycarbonyl thionocarbamate (BIPECTC) and O-(2-butoxy-1-methylethoxy) isopropyl-N-ethoxycarbonyl thionocarbamate (BMIPECTC), were synthesized in this study. Their collecting efficiencies in the flotation of chalcopyrite were investigated using flotation tests, adsorption measurements, ultraviolet spectra (UV) and Fourier transform-infrared spectroscopy (FT-IR) and density functional theory (DFT) calculations. The synthesized ether thionocarbamates showed better frothing properties than methyl-isobutyl-carbinol (MIBC) and stronger affinity to chalcopyrite compared with O-isopropyl-N-ethyl thionocarbamate (IPETC) and O-isobutyl-N-ethoxycarbonyl thionocarbamate (IBECTC). UV spectra analysis showed that the ether thionocarbamates react with Cu²⁺, with the exception of Fe²⁺, Ni²⁺, Zn²⁺ and Pb²⁺. Additionally, it was further confirmed by FTIR spectra that a chemical reaction occurs between copper ion and BIPECTC and BMIPECTC. The adsorption capacity measurements revealed that chalcopyrite exhibits good adsorption ability for ether thionocarbamates at an approximate pH of 8–10, which agrees with the flotation tests. The quantum chemistry calculation results indicated that the ether thionocarbamates exhibit stronger collecting ability for copper mineral in terms of frontier molecular orbital analysis, binding model simulation with copper ions and the molecular hydrophobicity compared with IPETC and IBECTC. The computational results are in very good agreement with the experimental results. Full article