“LENNIIGIPROCHEM” LLC, Saint Petersburg, Russia

А. А. Pedro, Professor, Head of the Chair of High-temperature Processes and Instruments, phone: 8 (812) 592-64-45

National Mineral Resources University, Saint Petersburg, Russia
A. P. Suslov, Prorector

This article examines the nature of the valve effect in electrode furnaces and the emergence of a DC component of the phase voltage. It is noted that the nature of the valve effect in the electrode furnace is related to the nature of the conversion of electrical energy in it, i.e. the degree of development of AC arc and conditions of contact of the electrodes with the materials of the reaction zone, mainly with the melt. Valve effect of AC arc is due to different conditions of electron emission from the cathode spot, when it is placed on solid carbon electrode or in viscous melt. Valve effect of electrode contact with the melt in the oresmelting furnace is caused by the difference of the electrode reaction with the melt in the adjacent half-cycles. Depending on the extent of the development of the valve effect of an AC arc and the valve effect of electrode contact with the melt, the value and the behavior of the constant component of the total phase voltage change. Equations that relate the value of the constant component to the current of electric arc and its current shunt are given. It is noted that the link between the nature of conversion of electric energy in ore-smelting furnace with the conditions of the technological process, as demonstrated by the change in the constant component of phase voltage, can be used to characterize the technological process in ore-smelting furnace. The example of industrial electric furnaces for production of processed phosphate, normal oxide and calcium carbide shows the behavior of the DC component, depending on the extent of the development of electric arc in the furnace, the quantity and composition of the melt in it, and the location of the working tip of the electrode with respect to the melt. This confirms the possibility of using a valve effect that exists in electric furnace to control technological and electrical parameters of a furnace: the degree of development of electric arc and amount of power developed in it, melt composition and quantity of the reducing agent in the reaction zone, and eventually expand the area of making electrical electrode furnaces control systems.

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