Grinding of wollastonite under gaseous environments: Influence on acidic/basic surface sites

Pugh, R.J.; Boutonnet-Kizling, Magali; Palm, C.

doi:10.1016/0892-6875(95)00088-8

Cited by 7 publications

(3 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While grinding wollastonite, the possible exposed sites with broken bonds are -O-Si + and -O-Ca + , which are electronpair acceptors (Lewis acids) and -Si-Oand -Ca-O -, which are electron-pair donors or bases. 38 It is plausible that Si-O bonds along the chain direction have a stronger linkage energy, of partial covalent nature, than Ca-O bonds between chains, which are weak ionic bonds. 11 Thus, Ca-O bonds break off earlier than Si-O bonds.…”

Section: Adsorption Of Dissociatedmentioning

confidence: 99%

Competitive Adsorption on Wollastonite: An Atomistic Simulation Approach

2005

View full text Add to dashboard Cite

Atomistic simulation techniques are used to simulate surface structure and adsorption behavior of scarcely floatable wollastonite mineral in the presence of molecular and dissociated water, methanoic acid, and methylamine. The latter two additives represent the two widely used collector head-group molecules. The static energy minimization code METADISE was used to perform the simulation to obtain pure surface energy and adsorption energy in the presence of added molecule. The hydroxylation was performed on those surfaces where low-coordinated silicon was made to saturate by bonding with hydroxyl group, and the subsequent charge neutralization was maintained by adding proton on single-coordinated surface oxygen. A comparison of surface energies revealed that all the surfaces become stabilized in the presence of added molecules; however, the presence of methylamine decreased the surface energy to lower values. Adsorption of dissociated water is preferred by the {100} and {102} surfaces, whereas the {001} surface preferred methylamine adsorption, because these show highly negative adsorption energies. In terms of molecular adsorption, the preferred adsorption sequence for all the surfaces is methylamine > methanoic acid > water without considering coadsorption. For the {100} and {102} surfaces, the adsorption energy values of carboxylic acid and amine are more negative than that of water and therefore we conclude that both carboxyl and amine head-group molecules adsorb preferably on wollastonite. Our simulation verify usability of carboxylic acid head group as widely used collectors for wollastonite flotation and, at the same time, it predicts the use of amine head-group collectors as possible modifiers, which corresponds well with our experimental findings.

show abstract

Section: Adsorption Of Dissociatedmentioning

confidence: 99%

Competitive Adsorption on Wollastonite: An Atomistic Simulation Approach

2005

View full text Add to dashboard Cite

show abstract

“…In more detail, acidic, basic, and non-polar solvents were tested, and the authors concluded that non-polar solvents resulted in higher acid absorption on the surface of the particles, while the absorption decreased with increasing acidity or basicity of the solvents [ 40 ]. In some cases, hybrid processes to modify wollastonite have been investigated, such as grinding in the presence of organic acids [ 31 , 38 , 42 , 43 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Filler Modification on the Thermal and Mechanical Properties of Composite Polypropylene/Wollastonite Drawn Fibers

2023

View full text Add to dashboard Cite

Polypropylene (PP) is one of the most commercially used thermoplastics, while a significant amount of PP is used in the form of fibers. In this study, the effects of modification of the filler on the thermal and mechanical properties of composite polypropylene/wollastonite drawn fibers were investigated. In this direction, the surface modification of wollastonite with various organic acids, such as myristic, maleic, malonic glutaric, pimelic, and suberic acid, and the use of two solvents were studied. The surface-modified wollastonite particles were used to produce composite polypropylene drawn fibers. The modification efficiency was found to be slightly better when a non-polar solvent (carbon tetrachloride) was used instead of a polar one (ethanol). FTIR experiments showed that myristic, maleic, malonic, and pimelic acid can strongly interact with wollastonite’s surface. However, the mechanical strength of the composite fibers was not increased compared to that of the neat PP fibers, suggesting inadequate interactions between PP and wollastonite particles. Furthermore, it was observed that the drawing process increased around 10% the crystallinity of all samples. Wollastonite modified with malonic acid acted as a nucleating agent for β-crystals. The onset decomposition temperature increased by 5–10 °C for all samples containing 2% wollastonite, either modified or not. The suggested modifications of wollastonite might be more suitable for less hydrophobic polymers.

show abstract

“…Different methods such as wetting experiments (contact angles) [3][4][5], inverse gas chromatography (IGC) [6,7], atomic force microscopy (AFM) [8,9], adsorption [10][11][12][13], microcalorimetry [14], titration [15,16], temperatureprogrammed desorption (TPD) [17][18][19], nuclear magnetic resonance spectroscopy (NMR) [20][21][22][23][24], X-ray photoelectron spectroscopy (XPS) [25][26][27], indicator dye adsorption [28,29,31], and infrared (IR) and Raman spectroscopy [30] are often used for acid/base characterization. However, it is rare that two or more methods are used in the same study for comparing or verifying the results.…”

Section: Introductionmentioning

confidence: 99%