Escuela de Ingeniería Química, Facultad de Ingeniería, Universidad del Bío-Bío, Concepción 4081112, Chile.
Faculty of Engineering and Architecture, Universidad Arturo Prat, Iquique 1100000, Chile.
Molecules. 2023 Apr 21;28(8):3629. doi: 10.3390/molecules28083629.
Iron ore is a fundamental pillar in construction globally, however, its process is highly polluting and deposits are becoming less concentrated, making reusing or reprocessing its sources a sustainable solution to the current industry. A rheological analysis was performed to understand the effect of sodium metasilicate on the flow curves of concentrated pulps. The study was carried out in an Anton Paar MCR 102 rheometer, showing that, in a wide range of dosages, the reagent can reduce the yield stress of the slurries, which would result in lower energy costs for transporting the pulps by pumping. To understand the behavior observed experimentally, computational simulation has been used by means of quantum calculations to represent the metasilicate molecule and the molecular dynamics to study the adsorption of metasilicate on the hematite surface. It has been possible to obtain that the adsorption is stable on the surface of hematite, where increasing the concentration of metasilicate increases its adsorption on the surface. The adsorption could be modeled by the Slips model where there is a delay in adsorption at low concentrations and then a saturated value is reached. It was found that metasilicate requires the presence of sodium ions to be adsorbed on the surface by means of a cation bridge-type interaction. It is also possible to identify that it is absorbed by means of hydrogen bridges, but to a lesser extent than the cation bridge. Finally, it is observed that the presence of metasilicate adsorbed on the surface modifies the net surface charge, increasing it and, thus, generating the effect of dispersion of hematite particles which experimentally is observed as a decrease in rheology.
铁矿石是全球建筑的基本支柱，但它的生产过程高度污染，且矿床的浓度越来越低，因此，重新利用或处理其来源是当前工业的可持续解决方案。本研究进行了流变学分析，以了解偏硅酸钠对浓缩纸浆流动曲线的影响。该研究在安东帕 MCR 102 流变仪上进行，结果表明，在较宽的剂量范围内，该试剂可以降低浆料的屈服应力，从而降低泵送输送纸浆的能源成本。为了理解实验中观察到的行为，通过量子计算来表示偏硅酸钠分子，并通过分子动力学来研究偏硅酸钠在赤铁矿表面的吸附，进行了计算模拟。已经可以获得吸附在赤铁矿表面是稳定的，随着偏硅酸钠浓度的增加，其在表面的吸附量增加。吸附可以通过 Slips 模型来建模，其中在低浓度下存在吸附延迟，然后达到饱和值。发现偏硅酸钠需要钠离子的存在才能通过阳离子桥型相互作用吸附在表面上。也可以通过氢键来识别它的吸附，但程度低于阳离子桥。最后，观察到吸附在表面上的偏硅酸钠会改变净表面电荷，从而增加表面电荷，并因此产生赤铁矿颗粒分散的效果，这在实验中表现为流变学的降低。
