Prevention and mitigation of acid rock drainage from mining are decisive for limiting environmental impact. Five by-products and industrial remnants (lime kiln dust, blast furnace slag, granulated blast furnace slag, cement kiln dust and fly ash) were investigated for their suitability to prevent acidity and metal(loid)s during leaching from highly sulfidic (50wt%, sulfide) waste rock in small ...

Algoritmus controly ohrievaného masívneho materiálu In numerous technological processes a change on the output follows change on the input pending specific time. This time is called dead time and if this time is too large, it causes problems in the control. This contribution is aimed at analyzing the algorithms of discreet regulation of the systems with dead time. Verified were classical PID re...

This paper presents a new application of a fractional order control system which controls the input energy to a three phase electric arc furnace. Graphite electrodes are used to convert electrical energy into heat via phase electric arcs. Constant arc length is desirable as it implies steady energy transfer from the graphite electrodes to the metallic charge in the furnace bath. With the charge...

The results of observation steelmaking oxidation stage at EAF-135 were analyzed with automated control system the electrical characteristics. There are three main zones in furnace working space, which differ by aggregate state materials them: arc discharge, melt and foamed slag. distribution data electric power over is given. active powers asymmetry arcs under single electrodes affected short n...

The rapid increase of non-linear loads in the last three decades has caused electrical quantities such as voltages and currents in 3-phase distribution systems to become distorted waveforms. This paper reviews, explains and discusses some new concepts, definitions and new available theory in the unbalanced and distorted systems. The usefulness of the proposed practical definitions is investigat...

Power quality determines the fitness of electrical power to consumer devices. .Voltage flicker and harmonics are the types of power quality problems that are introduced to the power system as a result of arc furnace operation. Utilities are concerned about these effects and try to take precautions to minimize them. Therefore an accurate model of an arc furnace is needed to test .In this paper a...

The rapid increase of non-linear loads in the last three decades has caused electrical quantities such as voltages and currents in 3-phase distribution systems to become distorted waveforms. This paper reviews, explains and discusses some new concepts, definitions and new available theory in the unbalanced and distorted systems. The usefulness of the proposed practical definitions is investigat...

The electric arc furnace (EAF) is used to produce high quality steel from steel scraps. The EAF uses plasma arc to generate heat for melting scarp or direct reduced iron (DRI). The liquid metal should be drained from the tap hole. Manual tapping operation of the EAF in the hot environment around the furnace is a potentially dangerous and time consuming task for the workers. Therefore, it is ess...

Research is made into the fuzzy control of electrode regulator systems of submerged electrical arc ferrosilicon furnace EAF. The equations of the electrode currents and furnace resistances are derived based on certain model for the submerged arc ferrosilicon furnace. This model takes into consideration the walls of furnace and the heat losses into external medium in addition to the heat transfe...

In this study electrical discharge process was used to increase surface wear resistance of pure aluminum. Pulse-on-time and pulse current were considered as input parameters of the electrical discharge process. Experimental results reveal that the electrical discharge process is a successful method for improving the surface wear resistance of aluminum, so that this method has greatly increased ...