Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pell...Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.展开更多
In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners ...In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners with different surfactant dosages and constituents were synthesized through intercalation reaction between sodium montmorillonite(NaM MT) and quaternary ammonium surfactants in aqueous solvents. The lubricating greases were prepared with the resulting organoclays, while the penetration and oil separation of lubricating greases were evaluated, respectively. The surface modification process of montmorillonite(MMT) was analyzed and the thickening mechanism of OMMT was discussed in this study. The experimental results showed that, with an increasing amount of surfactant, the basal spacing between the clay platelets was increasing and the structure of modifier molecules layer in the interlayer was changing from lateral bilayer to paraffin-type bilayer. The optimal properties of lubricating greases were achieved, when the structure of surfactant molecules loaded in the interlayer was the paraffin-type monolayer, which meant that the dosage of modifier was equal to 120—140 mmol/(100g). Meanwhile, it was found that the thickening performance, colloid stability, anti-wear and friction-reducing performance of lubricating greases were improved, when the surfactants were mixed with octadecyl trimethyl ammonium chloride(OTAC) and hexadecyl trimethyl ammonium chloride(HTAC). And the optimum mole ratio of two surfactants is was 1:1.展开更多
基金financial support by the National Key Research and Development Program of China(No.2023YFC2907801)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40760)the Scientific and Technological Project of Yunnan Precious Metals Laboratory,China(No.YPML-2023050276)。
文摘Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.
基金financially supported by the Chongqing Construction Project of Innovation Teams in Colleges and Universities-Petroleum Products Application Engineering and Technology(Project No.KJTD201342)the Chongqing Project of Innovation Research by Postgraduates(Project No.CYB16130)
文摘In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners with different surfactant dosages and constituents were synthesized through intercalation reaction between sodium montmorillonite(NaM MT) and quaternary ammonium surfactants in aqueous solvents. The lubricating greases were prepared with the resulting organoclays, while the penetration and oil separation of lubricating greases were evaluated, respectively. The surface modification process of montmorillonite(MMT) was analyzed and the thickening mechanism of OMMT was discussed in this study. The experimental results showed that, with an increasing amount of surfactant, the basal spacing between the clay platelets was increasing and the structure of modifier molecules layer in the interlayer was changing from lateral bilayer to paraffin-type bilayer. The optimal properties of lubricating greases were achieved, when the structure of surfactant molecules loaded in the interlayer was the paraffin-type monolayer, which meant that the dosage of modifier was equal to 120—140 mmol/(100g). Meanwhile, it was found that the thickening performance, colloid stability, anti-wear and friction-reducing performance of lubricating greases were improved, when the surfactants were mixed with octadecyl trimethyl ammonium chloride(OTAC) and hexadecyl trimethyl ammonium chloride(HTAC). And the optimum mole ratio of two surfactants is was 1:1.
