Magistritöö tulemusena sai tõestatud, et seadme parameetrite optimeerimine muudab selle töörežiimid efektiivsemaks ja suurendab rikastamisefekti.

Põlevkivi märgrikastamine suruõhuga veejoas ei jää efektiivsusnäitajatelt alla hetkel Eestis kasutatavast magnetiidiga rikastamise tehnoloogiast ja mille täiustamise võimalused on aastakümnetega ammendunud.

Setitis rikastamise eelis olemasoleva tehnoloogia ees on keskkonnasäästlikus ja majanduslikult odavam veemajandus.

Setiti kasutamine allmaatingimustes loob eelduse allmaarikastamisel tekkiva aheraine ladustamisele maa all.

Põlevkivi kvaliteedi parendamine parimate võimalike tehnoloogiatega suurendab selle väärtust keemiatööstuse toorainena ja toodab lisandväärtust nii peenkeemia- kui plastitööstuse valdkonnas.

Abstract

In the extraction and processing of mineral resources, more and more attention is paid today to the development of resource-efficient, circular economic and environmentally friendly technologies. Mineral enrichment is the separation of valuable mineral resources and waste material from raw materials without changing their chemical composition. The most common enrichment methods are mechanical enrichment, gravity enrichment, magnetic enrichment and electrostatic enrichment.

In Estonian oil shale mines, a method of gravitation enrichment is currently used for enriching the ROM, which is based on wetting the ROM in magnetite suspension, during which the mineral part of the ROM, the organic part and the closures are separated. However, the water management involved in this process is not environmentally safe, and it also requires the construction of large-scale slime- and sedimentary pools and other high-cost infrastructure. The cost of the process is also increased by buying various additives such as magnetite, etc. and the work-intensity in carrying out the process.
In 2019-2021, the mining and mineral technology research group at the TalTech Department of Geology, including the present author, was engaged in the search for more efficient and environmentally friendly oil shale technologies. Within the framework of the study, a database of the technologies of possible enrichment of oil shale was compiled and a calculation model was created, with the help of which the author analyzed the suitability of different technologies for enriching oil shale ROM. As a result of the studies, the suitability of sediment with a pulsating jet of water for oil shale enrichment was accepted, as well as the greater environmental sustainability and economic efficiency of this process compared to the magnetic suspension enrichment.

The theoretical studies were followed by practical activities, in the framework of which the methodology of the experimental work carried out on the pilot device for German scientists was compiled, the author prepared a batch of ROM in the Ojamaa mine and its transport to Germany, the University of Aachen. After the test work, he participated in determining the calorific value of the samples from Germany at the Institute of Energy Technology of TalTech.

In the course of completing the master's thesis, a number of research materials have been prepared and a follow-up work has been carried out for the research, which also became the main theme of the thesis – to study AllJig-S400 technical parameters, water jet pulse frequency and water tank pressure, the effect of changing values to increase the enrichment effect of the device.

To this end, the author supplied the required amount of trenches for experimental work from the Ojamaa mine, processed and tested it on an AllJig-S400 device in the GI Mining Conditions Laboratory, analogous to the German device. After the enrichment work, he participated in determining the calorific value of the ROM samples tested at the Department of Energy Technology of TalTech.
The goal set for the thesis was achieved, as in the course of the work the desired connections were found between the compressed air directed to the water tank and the frequencies of the pulses of the aquatic environment of the tank. The course of the test work and the analysis of the results confirms that optimizing the values of the operating parameters of the AllJig-S400 makes the operating modes of enrichment more efficient, which in turn leads to an increase in the enrichment effect, i.e. an increase in the calorific value of the enriched material compared to the calorific value of the input raw material.