Influence of Grinding and Sonication on the Crystal Structure of Talc

Abstract

Talc is an important industrial mineral with a broad range of applications. Particle size and crystal structure have a significant influence on the potential uses. The present study examined the influence of grinding and ultrasound treatment on talc from a new deposit, Gemerská Poloma, in Slovakia. The general knowledge that grinding produces progressive structural disorder leading to amorphization, whereas sonication has a negligible effect on the talc crystal structure, was confirmed by X-ray diffraction (XRD), infrared (IR) spectroscopy, and transmission electron microscopy (TEM). Partial reduction of particle size along with delamination was observed by XRD after sonication, low-angle laser light scattering (LALLS), scanning electron microscopy (SEM), and TEM. The specific surface area (SSA) increased slightly after prolonged sonication, but grinding initially caused a rapid increase in SSA followed by a drastic decrease after prolonged grinding time of up to 120 min which was attributed to the aggregation of amorphized talc. Sonication and grinding had different influences on the thermal behavior of the talc studied. Sonication decreased slightly the dehydroxylation temperature, whereas grinding added a significant mass loss at low temperature, arising from the dehydration of hydrated Mg cations released from the talc structure during amorphization. The initial high whiteness value of talc decreased slightly after grinding or sonication. Thermogravimetry was suggested as a useful tool to track and predict changes in the talc structure upon sonication and grinding.

Effects of inorganic filler on performance and cost effectiveness of a soybean‐based adhesive

“… After LCC and HCC were introduced into the DSF adhesive, these characteristic calcite peaks became weak but were still present, suggesting poor compatibility with the DSF adhesive, as indicated by the discontinuous cracks and grooves on the fracture surface of DSF‐LCC and the notable HCC aggregation on the fracture surface of DSF‐HCC in Figure , both of which were detrimental to the adhesion performance. The filler TC had obvious IR absorption at approximately 3676, 1431, and 1009 cm −1 , which was assigned to the stretching modes of OH, CO 3 2− , and SiO, respectively, and the absorption at 670 cm −1 was attributed to OH bending . These characteristic IR peaks of TC still appeared with high intensity in the IR spectra of DSF‐TC, demonstrating that TC was least compatible with the DSF adhesive matrix among the five selected fillers.…”

Synthesis of cyclic carbonates from epoxides and carbon dioxide catalyzed by talc and other phyllosilicates

“…The shape of the peaks between 15° and 40° could be attributed to structure distortion usually caused by conditions of growth and/or metamorphization of the mineral. In addition, the distortion can be due to effects of grinding that could cause progressive structural disorder and subsequent amorphization of crystallites [ 41 ]. It is also common that during intensive grinding, the XRD basal 001 peak of talc decreases in intensity, whereas the 002 peak may disappear completely and an increase in back-ground in the 2θ = 15°–40° due to the formation of amorphous material is also expected [ 41 ].…”

“…In addition, the distortion can be due to effects of grinding that could cause progressive structural disorder and subsequent amorphization of crystallites [ 41 ]. It is also common that during intensive grinding, the XRD basal 001 peak of talc decreases in intensity, whereas the 002 peak may disappear completely and an increase in back-ground in the 2θ = 15°–40° due to the formation of amorphous material is also expected [ 41 ]. Another important observation made is the similarity of the XRD pattern to the one obtained by Kogure and co-workers [ 47 ] in which the authors suggested that such a pattern is typical for silicates with extensive stacking disorder.…”

“…The absorption band at 1014 cm −1 is due to stretching vibration of Si-O of the [SiO 4 ] tetrahedra [39,40]. However, the observed intensities of some bands were relatively weak compared to those reported in previous studies [35,41,42]. This could be attributed to structural degradation of the octahedral and tetrahedral sheets under mechanical stress of grinding, and possibly lower content of OH groups in the pristine mineral.…”

“…This could be attributed to structural degradation of the octahedral and tetrahedral sheets under mechanical stress of grinding, and possibly lower content of OH groups in the pristine mineral. Some bonds in the talc structure such as Mg-O and Mg-OH may break during grinding, resulting in disruption of linkages between octahedral and tetrahedral sheets [41].…”