In this work the sintering ability of borosilicate (S53B50), borophosphate (P40B10) and phosphate (Sr) bioactive glasses was investigated. The glass powders were crushed and sintered in air at a heating rate of 10 °C/min for 2 hours at sintering temperatures between 480 °C–600 °C. The aim was to define the optimum sintering temperature prior to glass crystallization. The density of the samples was found to decrease when the temperature was increased up to 580 °C; probably due to the inhibition of the viscous flow of the particles during sintering thereby reducing the densification of the material. Such low porosity is not suitable in tissue engineering. To process highly porous scaffolds with porosity required for scaffold applicable to tissue engineering, the powders were further mixed with 60 vol.% and 70 vol.% of NH₄(HCO₃) foaming agent. Meanwhile, the density of the samples sintered with NH₄(HCO₃) was found to decrease with an increase in NH₄(HCO₃) content. This indicates an increase in porosity of the samples. The glass compositions reached an open porosity of more than 60% at the addition of 70 vol.% NH₄(HCO₃). In addition, SEM micrograph revealed large pores with good interconnection between the pores.

In this work, glasses within the borosilicate borophosphate and phosphate family were sintered into 3D porous scaffolds using 60 and 70 vol. % NH₄(HCO₃) as a foaming agent. All scaffolds produced remained amorphous; apart from one third of the glasses which crystallized. All produced scaffolds had porosity >50% and interconnected pores in the range of 250–570 µm; as evidenced by µCT. The in-vitro dissolution of the scaffolds in SBF and changes in compression were assessed as a function of immersion time. The pH of the solution containing the borosilicate scaffolds increased due to the typical non-congruent dissolution of this glass family. Borophosphate and phosphate scaffolds induced a decrease in pH upon dissolution attributed to the congruent dissolution of those materials and the large release of phosphate within the media. As prepared, scaffolds showed compressive strength of 1.29 ± 0.21, 1.56 ± 0.63, 3.63 ± 0.69 MPa for the borosilicate, borophosphate and phosphate samples sintered with 60 vol. % NH₄ (HCO₃), respectively. Evidence of hydroxyapatite precipitation on the borosilicate glass scaffolds was shown by SEM/EDS, XRD and ICP-OES analysis. The borophosphate scaffolds remained stable upon dissolution. The phosphate scaffolds were fully crystallized, leading to very large release of phosphate in the media.

Recent advancements in nano-enhanced froth flotation technology have significantly transformed the mineral processing landscape, particularly in the efficient recovery of fine mineral particles. This paper provides a comprehensive review of published literature regarding recent advancements in nanotechnology aimed at improving the flotation of fine minerals. The integration of nanobubbles and nanoparticles such as collectors, depressants, and frothers into conventional froth flotation systems, has been found to improve both the efficiency and selectivity of fine particle separation. The effects of nanoparticles (NPs) and nanobubbles (NBs) on the flotation of fine minerals are also examined. NPs and NBs can enhance the hydrophobicity selectivity of targeted minerals, thereby improving the performance of mineral flotation. The synthesis and characterization methods of the nanoparticles are also briefly outlined. Furthermore, the implications of nanotoxicology, addressing potential environmental and health concerns associated with the use of nanomaterials are also highlighted. This review highlights notable advancements in the application of nanoparticles and nanobubbles in the flotation of minerals, indicating their potential to enhance or replace the traditional reagents that are currently utilized.