Clay and refractory materials slurries in inductively coupled plasma optical emission spectrometry: effects of mechanochemical synthesis on emission intensities of analytes

Abstract

Neste trabalho foi investigada a aplicação da síntese mecanoquímica para promover reações na amostra e sintetizar novos compostos visando aumentar as intensidades de emissão de elementos presentes em suspensões de argilas e materiais refratários quando introduzidas em espectrômetro de emissão óptica com plasma acoplado indutivamente com configuração axial. A hipótese formulada é que é possível gerar compostos mais voláteis durante a moagem e esses novos compostos causam aumento da intensidade dos sinais de emissão para os analitos em suspensões introduzidas no plasma. A ação de dois modificadores, LiBO 2 e Na 2 CO 3 , adicionados durante a etapa de moagem foi investigada.As argilas e materiais refratários foram moídos juntamente com os modificadores químicos durante 2 h usando um moinho de bolas de alto impacto com recipiente e bolas de carbeto de tungstênio. As suspensões foram preparadas dispersando as argilas e os materiais refratários modificados em solução 10% v v -1 HNO 3 e, posteriormente, sonicadas em banho de ultra-som para melhorar a homogeneização. Os compostos produzidos durante a etapa de moagem foram caracterizados por difração de raios X e análise termogravimétrica. Ambas as técnicas indicaram a formação de novos compostos nas argilas e materiais refratários por síntese mecanoquímica. Os efeitos da modificação química foram avaliados pelas mudanças nas intensidades de emissão dos analitos Al, Ca, Fe, K, Mg, P, Si e Ti. Ambos modificadores causaram aumento na sensibilidade para todos os analitos de até 665% (Na 2 CO 3 ) e 583% (LiBO 2 ) quando comparados às intensidades dos sinais de emissão obtidos para os analitos nas suspensões preparadas com as amostras sem modificação química.The developed work investigated the application of mechanochemical synthesis for promoting reactions in the samples and for synthesizing new compounds for increment of emission intensities of analytes in clays and refractory materials slurries in inductively coupled plasma optical emission spectrometry with axial viewing. The hypothesis is that it is possible to generate more volatile compounds during the grinding step and these new compounds will increase the intensities of emission signals for slurries introduced in the plasma. The action of two chemical modifiers, LiBO 2 and Na 2 CO 3 , added during the grinding step was evaluated. The clays and refractory materials mixed with the chemical modifier were ground for 2 h using a high impact ball mill with a tungsten carbide grinding container and balls. Slurries were prepared by dispersing the modified clays and refractory materials in 10% v v -1 HNO 3 solution and by shaking them in an ultrasonic bath to ensure good dispersion. The compounds produced during the grinding step were characterised by X-ray diffraction and thermogravimetric analysis. Both techniques indicated the formation of new compounds in clays and refractory materials by mechanochemical synthesis. Chemical modification effects were evaluated by changes of the emission intensities of Al, Ca, Fe, K, Mg, P, ...

The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties: insights from theory

“…It is an excellent basic flux for silicate analysis [63], for the synthesis of low-density γ -Al 2 O 3 from high-density α-Al 2 O 3 [64], for the identification and characterization of resistant minerals containing uranium and thorium [65] and for the growth of single crystals [66][67][68]. LMB is also used as a chemical modifier during mechano-chemical synthesis processes for generating new compounds from clays and refractory materials [69]. Because of its deep-ultraviolet transparency combined with mechanical durability and high optical damage thresholds [70,71], LMB is one of the most attractive materials for wide bandgap non-linear optics.…”

Formation and Mobility of Li Point Defects in LiBO2: A First-Principles Investigation

“…5À7 LMB is also used as a chemical modifier during the mechano-chemical synthesis processes for generating new compounds from clays and refractory materials. 8 Because of its deep ultraviolet transparency combined with mechanical durability and high optical damage thresholds, 9,10 LMB is one of the most attractive materials for wide-band-gap nonlinear optics.…”

Microsolvation of LiBO2 in water: anion photoelectron spectroscopy and ab initio calculations

“…Interesting results have been obtained for several salts by anion PES combined with theoretical calculations. LiBO 2 melt is widely used as a flux or a chemical modifier [43][44][45][46][47][48] due to its low melting point, favorable dissolvability, high SHG coefficient, 49 high hardness and its ability to prevent transition-metal contamination. 28 Metaborate (BO 2 À ) is a popular and important boron oxide anion and has been extensively studied both experimentally and theoretically.…”

“…26 Lithium metaborate is an important alkali metaborate. LiBO 2 melt is widely used as a flux or a chemical modifier [43][44][45][46][47][48] due to its low melting point, favorable dissolvability, high SHG coefficient, 49 high hardness and its ability to prevent transition-metal contamination. 50 Aside from LiBO 2 melt, nanostructurisation of LiBO 2 can be utilized in ion conductors, battery systems, fuel cells or sensors 51,52 because of the Li ion conductivity.…”