Purification of quartz using an environment-friendly method is important in the contaminants removal. This paper presents advanced method based on calcination pretreatment combined with ultrasound-assisted leaching, for removing iron impurities from industrial quartz. The solvent used is a mixture comprised by diluted hydrochloric acid and oxalic acid. The effects of experimental parameters were investigated and the purification mechanism was discussed using particle size analyzer, scanning electron microscope and polarized light microscope. SiO2 content of concentrate could be increased from 99.6828% to 99.9047%, which achieved 3N level high purity quartz, and Fe2O3 content reduced from 0.0857% to 0.0223%, under the optimal conditions, i.e., calcination temperature of 900 °C, holding time of 2 h, oxalic acid concentration of 10 g/L, hydrochloric acid concentration of 5%, liquid solid ratio of 5, leaching temperature of 60 °C, ultrasound power of 400 W and treatment time of 30 min. Compared to conventional method, the proposed method significantly accelerates the leaching process and increases the iron removal rate. At the same time, the method also can remove gas-liquid inclusions. and Yang Changqiao, Li Suqin, Bai Jiaxing, Han Shuaishuai.
The objective of this work is the chemometric quantification of minerals in rocks. A chemometric method was developed for the determination of chlorite, muscovite, albite and quartz in claystones and clay shales using infrared spectroscopy. Bromide pellets and diffuse reflectance were used to measure the infrared spectra; principa l component analysis and partial least-squares regression were used as chemometric methods. Spectral regions (4000-3000 cm-1 and 1300-400 cm-1) containing important spectral information were chosen by principal compone nt analysis. The calibration models were created by a partial least-squares regression. The mean relative error and relative standard deviation were calculated for the assessment of accuracy and reproducibility. The value of the mean relative error was about 10 % for most of the calibration models. The value of the relative standard deviation ranged from 1.1 to 3.0 % for most calibration models based on diffuse reflectance spectra and from 4.0 to 9.2 % for most calibration models based on spectra obtained with bromide pellets., Michal Ritz, Lenka Vaculíková, Eva Plevová, Dalibor Matýsek and Jiří Mališ., and Obsahuje bibliografické odkazy
The paper studies the connection between the X-ray and thermo quartz luminescence, the massif formation facie features and differentiation of magmatic melt features, using the example of the Permian-Triassic granitoids from the Kolyvan-Tomsk folded belt (KTFB; the Kolyvan, the Barlak, the Ob, and the Novosibirsk rock massifs). The X-ray luminescence optical spectra and the thermoluminescence curves of quartz from the massifs listed above are obtained. The quartz luminescence is proven to be linked to the features of the magmatic melt differentiation. It is shown that the equivalence of the X-ray- and the thermoluminescence of granitoids quartz from different massifs are the result of similar conditions and mechanisms of the granitoids formation with close establishment periods. The obtained data make it possible to consider the KTFB granitoid magmatism as a result of natural magmatic differentiation of the original magma and to use the quartz emission spectra for typing granitoid massifs. The individuality of the Novosibirsk massif quartz, manifested in intense luminescence of Fe 3+, defects of O * (370 nm) and thermoluminescence (TL) at 180-220 °C, can be associated with high fugacity of oxygen, increased temperature and rate of mineral formation in rock collapse mode under tectonically active zone conditions. At the same time, the obtained data provides evidence for the differences in the leucocratic magmatism of the area, allowing differentiation of the Kolyvan-Tomsk folded belt leucogranites into the leucogranites of the Novosibirsk massif (Mo-W type of mineralization) and the leucogranites of the Kolyvan and the Barlak massifs characterized by rare metal mineralization (stannic-tungstic-beryllic with silver). and Boroznovskaya Nina Nikolayevna, Nebera Tatyana Stepanovna.