# Micro-Nanobubble Technology in Surface Cleaning and Defouling
## 3 Advanced Applications of NBs in Precision Surface Cleaning
### Flotation and Mineral Processing  
NBs are useful for altering surface interactions, which are essential for separating fine and ultrafine particles in mineral processing, because of their small size, large surface area, and energy release upon collapse [74]. NBs significantly increase flotation efficiency and recovery rates by encouraging particle agglomeration, changing surface hydrophobicity, and facilitating reagent desorption [66]. This section examines several studies that demonstrate the potential of NBs in mineral processing, with an emphasis on how they can be used to improve flotation performance, clean mineral surfaces, and streamline separation procedures. Bubble visualization of apatite and quartz grain surfaces was studied by [PERSON] et al. [75]. They found that MBs (mean diameter of 70 \(\upmu\)m) nucleated and grew, while the population of macrobubbles (mean diameter of 1 mm) increased only after conditioning with NBs (mean diameter of 150-200 nm) (Figure 11). The hypothesis of \"surface conditioning\", according to which BNBs seem to adhere quickly to pulverized mineral surfaces, especially if those surfaces are hydrophobic, was confirmed by this investigation. In this case, the attachment of larger bubbles was improved by the NBs, which increased flotation recovery and process kinetics. Consequently, at the first 1.5 min, approximately 95% P\({}_{2}\)O\({}_{5}\) recovery was attained, which was 9% higher than the maximum flotation in the normal tests at 4 min. Compared with the normal test, flotation recoveries were boosted by approximately 23% when quartz was conditioned with NBs. Quartz particle recovery in the first minute was approximately double that of the standard. NBs are believed to offer good potential for material flotation. [PERSON] et al. [76] examined the function of MNBs produced during hydrodynamic cavitation in a diaspore flotation system to desorb flotation chemicals, especially sodium oleate (NaOl). In particular, when the amount of pre-adsorbed NaOl was low, the results demonstrated that MNBs could efficiently remove NaOl from diaspore surfaces. By decreasing the hydrophobicity of diaspore particles, desorption increased the flocs' friability and breakage propensity, thereby increasing the efficiency of mineral separation. It is probable that the MNBs' increased surface area and energy release during the collapse led to improved reagent desorption. According to these results, which were validated by  
Figure 11: Graphical representation of the main mechanisms involved in the flotation assisted by NBs. Reproduced with permission from [75], © 2018 Elsevier Ltd.  
flotation tests on a diaspore/kaolinite mixture, MNBs may enhance the flotation process by lowering gangue entrapment in flocs and improving mineral separation. [PERSON] et al. [24] reviewed the potential of NBs for enhancing froth flotation during mineral processing, particularly for fine and ultrafine particles. Compared with traditional flotation bubbles, NBs have smaller radii and are more stable, which makes them useful for increasing recovery rates. By facilitating particle agglomeration and enhancing the electrostatic attraction between particles through charge inversion, NBs increase flotation efficiency. There are still issues, such as competition from other materials in the flotation environment and the requirement for more effective NBs production and characterization techniques, even though NBs flotation has demonstrated promise in enhancing particle recovery. The review highlighted that to facilitate industrial-scale use, a thorough theory of NB stability and behavior is required along with developments in NB manufacturing technology and particle identification methods. [PERSON] et al. [77] emphasized the special qualities of NBs and their use in froth flotation, particularly in wastewater treatment and mineral processing. Given their unique physical properties, including stability, large surface area, and small size, NBs show great promise for enhancing flotation performance, particularly for fine particles.