Adsorption Mechanism of 4-Amino-5-mercapto-1,2,4-triazole as Flotation Reagent on Chalcopyrite.

A novel compound 4-amino-5-mercapto-1,2,4-triazole was first synthesized, and its selective adsorption mechanism on the surface of chalcopyrite was comprehensively investigated using UV-vis spectra, zeta-potential, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy measurements (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and first principles calculations. The experimental and computational results consistently demonstrated that AMT would chemisorb onto the chalcopyrite surface by the formation of a five-membered chelate ring. The first principles periodic calculations further indicated that AMT would prefer to adsorb onto Cu rather than Fe due to the more negative adsorption energy of AMT on Cu in the chalcopyrite (001) surface, which was further confirmed by the coordination reaction energies of AMT-Cu and AMT-Fe based on the simplified cluster models at a higher accuracy level (UB3LYP/Def2-TZVP). The bench-scale results indicated that the selective index improved significantly when using AMT as a chalcopyrite depressant in Cu-Mo flotation separation.

Investigating the Mechanism of Diethylenetriamine Pentamethylene Phosphonic Acid as a Depressant for Calcite Flotation of Fluorite.

Fluorite and calcite have been attracting research attention for a long time. This paper reports on an investigation of the use of diethylene triamine pentamethylphosphonic acid (DTPMPA) as a chelating inhibitor. DTPMPA was used as a chelating inhibitor to study the flotation, separation, and adsorption behaviors of fluorite and calcite minerals. The microflotation experiment showed that the maximum separation of fluorite and calcite can be achieved with a DTPMPA dosage of 1.5 × 10-4 mol/L under weakly alkaline conditions (pH = 8). Zeta potential measurement, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to confirm that DTPMPA was adsorbed on the surface of calcite, inhibiting NaOl adsorption. Additionally, density functional theory calculations showed that oxygen in the DTPMPA phosphate group formed the most stable bidentate binuclear adsorption configuration by chelating with calcium on the calcite surface. Through detection analysis and simulation calculations, the results showed that DTPMPA exhibited significantly weaker adsorption on fluorite compared to that on calcite, highlighting its selective inhibition ability on calcite.

Research on prediction of coal water medium separation effect based on multi-models.

To improve the separation efficiency of raw coal and ensure clean use, the accurate calculation of the partition coefficients (PCs) in coal water medium sorting is required. Single models have been used to predict the partition coefficient (PC) for decades, but their accuracy remains constrained. This study proposes a multi-model (MM) calculation method based on the Gompertz model (GM), the Logistic model (LM), the Arctangent model (AM), and the Approximate formula (AFM) to improve the accuracy of the predicted coal water medium sorting PCs. Four groups of coal samples and two specific cases were used to verify the accuracy of the MM calculation method. The PCs of the MM method had a minimal Ef (0.91-8.84), a maximal R2 (0.9648-0.9994), a maximal F-value (199.17-11352.31), and the highest significance of all the models. The MM method was found to be the most suitable of all the models for predicting any coal water medium separation process. Further, when calculating the PC for cleaned coal ash, the separation density of MM is closer to the actual separation density than that of either the GM, LM, AM, or AFM models. The MM method, therefore, produces more accurate results compared to a single model. MM is expected to predict the PC based on the required cleaned coal ash, and then regulate the sorting density to improve the production efficiency.

Selective adsorption of tannic acid on calcite and implications for separation of fluorite minerals.

Selective adsorption of tannic acid (TA) on calcite surfaces and the implications of this process for the separation of fluorite ore were studied by microflotation tests, surface adsorption experiments, zeta potential measurements, UV-vis analysis, and X-ray photoelectron spectroscopy (XPS) analysis. The microflotation tests indicated that TA, when added before sodium oleate (NaOl), could selectively depress calcite from fluorite at pH 7. Surface adsorption experiments revealed that TA hinders the interaction of NaOl with calcite. The zeta potential of calcite became more negative with TA than with NaOl. However, the characteristic features of TA adsorption were not observed on fluorite, suggesting that the dominant adsorption sites are dissimilar on the fluorite and calcite surfaces in the pulp. UV-vis spectroscopy, XPS, and solution chemistry analysis were utilized to obtain a better understanding of the mechanism for selective adsorption of TA as well as the key factors determined by the Ca2+ and Ca(OH)+ components on the mineral surfaces. A possible adsorption mechanism along with an adsorption mode is proposed for the surface interaction between TA and calcite.