National Repository of Grey Literature 5 records found  Search took 0.00 seconds. 
Kaoline whitness improvement by mechano-chemical treatment
Uher, Samuel ; Bartoníčková, Eva (referee) ; Šoukal, František (advisor)
The thesis deals with the issue of increasing the whiteness of kaolin by acid leaching simultaneously with milling. Kaolin was prepared from kaolin raw material from the Otovice quarry (Sedlecký kaolin a.s.), which was subsequently grined in suspension with oxalic acid, tartaric acid or citric acid in a ball planetary mill. We had been observing the influence of the type and concentration of acid and grinding time on many aspects, such as: the whiteness index, the amount of leached Fe and Ti, the distribution of Fe and Ti in kaolin, and the kaolin structure order.
Increasing the whiteness of kaoline
Bartošík, Jan ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The thesis deals with the issue of increasing the whiteness index of kaolin raw material. The research was focused on floating the kaolin suspension and the subsequent processes related to increasing the whiteness index. Increasing the whiteness of the kaolin raw material took place on the basis of acid leaching. The eluents were based on sulfuric acid, phosphoric acid, oxalic acid and sodium bisulfite. The leaching process was influenced by the temperature and concentration of the leaching agent. Floated and leached kaolin samples were characterized by several methods. The XRD method investigated the mineralogical composition and the kaolinite structure order. The distribution of chromogenic components was monitored by SEM-EDS. Residues of organic matter was determined by COD test and the concentration of chromogenic components in the extract was monitored by the ICP-OES method. Last but not least, the index of whiteness was measured, the increase of which is the aim of the diploma thesis, using a UV-VIS spectrometer with reflective extension.
Kaoline whitness improvement by mechano-chemical treatment
Uher, Samuel ; Bartoníčková, Eva (referee) ; Šoukal, František (advisor)
The thesis deals with the issue of increasing the whiteness of kaolin by acid leaching simultaneously with milling. Kaolin was prepared from kaolin raw material from the Otovice quarry (Sedlecký kaolin a.s.), which was subsequently grined in suspension with oxalic acid, tartaric acid or citric acid in a ball planetary mill. We had been observing the influence of the type and concentration of acid and grinding time on many aspects, such as: the whiteness index, the amount of leached Fe and Ti, the distribution of Fe and Ti in kaolin, and the kaolin structure order.
Increasing the whiteness of kaoline
Bartošík, Jan ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The thesis deals with the issue of increasing the whiteness index of kaolin raw material. The research was focused on floating the kaolin suspension and the subsequent processes related to increasing the whiteness index. Increasing the whiteness of the kaolin raw material took place on the basis of acid leaching. The eluents were based on sulfuric acid, phosphoric acid, oxalic acid and sodium bisulfite. The leaching process was influenced by the temperature and concentration of the leaching agent. Floated and leached kaolin samples were characterized by several methods. The XRD method investigated the mineralogical composition and the kaolinite structure order. The distribution of chromogenic components was monitored by SEM-EDS. Residues of organic matter was determined by COD test and the concentration of chromogenic components in the extract was monitored by the ICP-OES method. Last but not least, the index of whiteness was measured, the increase of which is the aim of the diploma thesis, using a UV-VIS spectrometer with reflective extension.
Photoinduced Darkening and Bleaching in Amorphous As2S3 Thin Films
Munzar, Martin ; Tichý, Ladislav
Photodarkening significantly depends on the (the excitation light wavelength, the penetration depth of the excitation light, the incident photon flux and the number of absorbed photons in a sample.

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