@article{scholars11597,
            year = {2019},
         journal = {SN Applied Sciences},
       publisher = {Springer Nature},
          number = {5},
          volume = {1},
            note = {cited By 3},
             doi = {10.1007/s42452-019-0398-3},
           title = {Effect of pH on the stability of quartz in a multi-phase system of kaolinite, hydrous Al (hydr)oxide and quartz},
        abstract = {The stability of quartz in a multi-phase system of kaolinite and Al (hydr)oxides and quartz has been addressed in quite a few studies. However, the impact of pH on these multi-mineral interactions has not been elucidated. Therefore, this study shows the different dissolution behaviour and surface morphology of quartz admixed with hydrous kaolinite and aluminium (hydr)oxides under variable pH conditions. This will enhance the predictability of silica behaviour in natural rock weathering and reservoir systems. Scanning electron microscopy characterization shows that kaolinite and Al (hydr)oxides exhibit high-quality coating of quartz surface at acidic and alkali pH by creating a surficial secondary layer that allows agglomeration of other minerals, while Fourier transform infrared analysis showed shifts in peak positions of Si{\^a}??O quartz from 691{\^A} cm{\^a}??1 and 692{\^A} cm{\^a}??1 at pH 5 and 7 to 686{\^A} cm{\^a}??1 at pH13, and broadening of characteristic hydroxide and siloxane peaks as well as the formation of new Si{\^a}??O{\^a}??Al bonds at pH 13, suggesting structural changes in hydrous aluminosilicates and Al hydroxides (broken bonds of Al{\^a}??O{\^a}??Si, Al{\^a}??O{\^a}??Al and Si{\^a}??O{\^a}??Si) and Al substitution for Si in tetrahedral sheets. The dissolved silica in quartz{\^a}??kaolinite{\^a}??Al (hydr)oxides interactions is relatively lower under alkali conditions compared to acidic pH. Quartz dissolution was highest at pH 7; signifying the interaction of quartz with Al (hydr)oxides and kaolinite is favourable for quartz dissolution at neutral pH range. The results indicate that quartz interaction with kaolinite and Al (hydr)oxides is dependent on pH. Quartz coating by kaolinite and Al (hydr)oxides is more effective under alkali pH conditions, given the low solubility of Al within this pH range. {\^A}{\copyright} 2019, Springer Nature Switzerland AG.},
        keywords = {Aluminum coatings; Aluminum metallography; Dissolution; Hydraulic servomechanisms; Kaolinite; Morphology; pH; Quartz; Scanning electron microscopy; Silicon; Surface morphology; System stability; Weathering, Dissolution behaviour; Fourier transform infra reds; High quality coatings; Mineral interactions; Multi phase systems; Quartz dissolution; Reservoir systems; Tetrahedral sheets, Aluminum compounds},
             url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100721142&doi=10.1007\%2fs42452-019-0398-3&partnerID=40&md5=932fc20fc413a48aeab2d38b966b34c7},
            issn = {25233971},
          author = {Ali, A. M. and Padmanabhan, E. and Mijinyawa, A. and Kwaya, M. Y.}
}