The investigation of the effects of design parameters of triboelectrostatic separator on mineral separation

In this thesis, it is aimed to design triboelectiric separation unit and investigate the effect of parameters in triboelectric separation performance. The separation of the particles according to their electrical charges is a very old separation method used in mineral processing. However, it is not a very common method because of its high operational cost. In this method, mineral particles have been charged in an electrical field according to their conductivity and separated by attracting or repelling between positively or negatively charged electrodes. Triboelectric is the name of static electric that is occurred by friction of two different materials. Friction of one particle to each other or to other material, loads the particles with negative or positive charges depending on its conductivity and surface properties. The particles, which have different electrical charge (negative or positive), move different directions in an electrical field. Hence, it is possible to separate a particle from each other according to their charges. In literature it is common to charge particles with friction. Investigation of the electric charge required for the high potential electric field and investigate of the effects of different parameters on the mineral separation are the main objective and original value of this thesis. For this purpose triboelectric seperaton unit is desiged and test are applied with changed varriables to understand separation performance of this unit. In this unit, the triboelectrical charging of the surfaces of the particles and the potential static charge required to separate the particles are provided by friction. Conventional electrostatic separators require external high potential transformers that convert alternative current to direct current. For this purpose, direct current transformers with high number of turn are required. Main problems with this tranformers are high consumption of power, cooling problems during operation and dangerous work enviroment. In this thesis, it is aimed to build a system that producing the required electrical potential by friction. Hence, required electrical vii energy consumption will be lower and there will be less operational problems. Considering to concentional system, innovative part of this system is required energy is supplied from produced from friction. In addition to these static charge is not provide high electric current and come in with more safe work environment. The operational cost of the conventional electrostatic separators is relatively high because of its high voltage requirements. Rather than electrostatic separators and other conventional processing equipment, triboelectric separator does not have high-energy consumption. Major advantage of setup, which is built in Mining Engineering Department of Hacettepe University, is to produce high voltage up to 35 kV with friction. This is the innovative part of the project. Furthermore this is dry equipment which reduces the water consumption and it does not need any chemicals. It is environmentally friendly method. In this study, artificial test samples are used to investigate the separation performance of the system. This study provides the required information about design parameter for this new equipment. The most important advantage of this system, which was established in the Department of Mining Engineering at Hacettepe University, is that it produce static loads up to 35 kV by friction. This method of separation is a dry separation method and one of the eco-friendly methods used in mining due to the fact that it does not requre water or any chemical. The main structure of the unit had been designed by computer program and then it is built with appropriate materials which are choosen from triboelectric series. The electricity produced is transferred to electrodes which have different size, shape and material. The mineral particles had been also charged by mixing in a mixer and then fed into the electrical field occurred between the electrodes via vibrating feeder. Tests are performed on synthetic mixtures of liberated magnetite-quartz samples to prevent any effect of ore in separation performance. After the promising result with the synthetic samples, tests are performed with industrial mineral, metal ore, coal and mixture of recyclable material samples. Results of these tests indicated that most of these samples could be separated successfully with this new method.