diplomsko delo
Eva Gabrijel (Author), Amalija Golobič (Mentor)

Abstract

Trdne snovi so lahko kristalinične ali amorfne. Amorfne imajo red kratkega dosega, medtem ko je za kristalinične snovi značilen red dolgega dosega. Red dolgega dosega je v pravih kristalih povezan s tem, da njihovo zgradbo lahko opišemo s periodičnim ponavljanjem osnovne celice. Zaradi reda dolgega dosega pri kristaliničnih vzorcih pride, če jih obsijemo z rentgensko svetlobo do uklanjanja (diskretnih) rentgenskih žarkov, kar pa nam s pomočjo računalniških programov omogoči identifikacijo snovi v vzorcih. Žarki se namreč uklonijo pod določenimi koti, ki so ob izbrani valovni dolžini rentgenske svetlobe značilni za vsako snov, zato lahko na podlagi uklonske slike, ki ji rečemo tudi difraktogram, ugotovimo, katere snovi se nahajajo v trdnem vzorcu. V diplomskem delu sem tako z rentgensko praškovno difrakcijo ugotavljala, kateri minerali sestavljajo kamnine in prst v vzorcih, ki sem jih nabrala v okolici mojega doma na Otočcu na Dolenjskem. Pri karakterizaciji sem uporabljala program Crystallographica Search Match - CSM, ki bere podatkovno zbirko praškovnih difraktogramov številnih standardov (PDF), in jih primerja z izmerjenim difraktogramom obravnavanega vzorca. Za vzorčenje na Otočcu sem se odločila, ker sem želela izvedeti več o sestavi tal v mojem domačem kraju. Približno 10 centimetrov pod površjem sem nabrala 8 vzorcev. Na vsaki lokaciji sem nabrala prst in kamenje. Pred merjenjem difraktogramov vzorcev na difraktometru sem vsak vzorec zmlela in homogenizirala v ahatni terilnici. S kvalitativno fazno analizo s programom CSM sem ugotovila, da so bili vsi vzorci kamnin v pretežni meri sestavljeni iz dolomita. Vsebovali so še majhno količino kremena, v dveh sem identificirala tudi zelo majhno količino kalcita. Vzorci prsti pa so vsebovali veliko kremena, razen enega vzorca tudi precej dolomita. Vse prsti so vsebovale še malo silikatnega minerala mikroklina, nekatere pa še malo klinoklora in rutila. Sestava prsti je smiselna glede na kemično preperevanje opisanih kamnin.

Keywords

rentgenska praškovna difrakcija;difraktogrami;Braggova enačba;kvalitativna fazna analiza;kamnine;prst;diplomske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher: [E. Gabrijel]
UDC: 543.442.3:549(043.2)
COBISS: 41497859 Link will open in a new window
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Downloads: 142
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Other data

Secondary language: English
Secondary title: MINERAL COMPOSITION OF ROCKS AND SOILS AT OTOČEC REGION
Secondary abstract: Solids can be crystalline or amorphous. Amorphous have a short-range order, while crystalline solids have a long-range order due to the fact that their structure can be described by periodic repetition of the unit cell. If crystals are exposed to X-rays, discrete diffracted X-rays are emitted, which enables us to identify substances in the samples with the help of computer programs. The rays are diffracted at angles, which are characteristic for each substance at the selected X-ray wavelength, so we can determine which substances are in the solid sample on the basis of the diffraction pattern, also called the diffractogram. In my diploma work, I used X-ray powder diffraction to determine which minerals make up the rocks and soil in the samples I collected in the vicinity of my home at Otočec in the Dolenjska region. For the characterization, I used the program Crystallographica Search Match - CSM, which reads a database of powder diffractograms of many standards (PDF) and compares them with the measured diffractogram of the sample. I decided to sample at Otočec because I wanted to know more about the composition of the soil in the vicinity of my home. About 10 cm below the surface I collected 8 samples. I collected soil and stones at each location. Before measuring the diffraction patterns of the samples on the diffractometer, I ground and homogenized each sample in an agate mortar. By qualitative phase analysis with the CSM program I found that all rock samples were predominantly composed of dolomite. They also contained a small amount of quartz. In two of them I also identified a very small amount of calcite. The soil samples, however, contained a lot of quartz, except for one sample also a lot of dolomite. All soils contained a small amount of the silicate mineral microcline, and some of them also clinochlore and rutile. The composition of the soil is reasonable regarding to chemical weathering of such rocks.
Secondary keywords: X-ray powder diffraction;qualitative phase analysis;rocks;soil;
Type (COBISS): Bachelor thesis/paper
Study programme: 1000374
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, VSŠ Kemijska tehnologija
Pages: 31 str.
ID: 12208360