SU957081A1 - Melted slag electric conductivity measuring device - Google Patents

Description

(54) DEVICE FOR MEASURING THE ELECTRICAL CONDUCTIVITY OF THE MELTED SLAG

The invention relates to a physicochemical analysis and can be used to determine the electrical conductivity of ionic liquids, mainly molten slags at high temperatures.

A device for determining the electrical conductivity of ionic liquids is known, which contains electrodes connected to an alternating current source and a recorder I.

The disadvantage of the device is the instability of the measurements.

Closest to the proposed technical solution is a device for measuring the electrical conductivity of molten slag, containing electrodes connected to a measuring unit, located in the crucible with the melt 21.

A disadvantage of the known device is the low measurement accuracy due to errors that can exceed more than 100% of the measured value. Errors are caused by influencing the measurements of the active resistances of the near-electrode resistivity depending on the nature and chemical composition of the expansion Ba, the material of the electrodes, and the density and frequency of the measuring current.

The purpose of the invention is to improve the measurement accuracy.

The goal is achieved by the fact that in the device containing electrodes connected to the measuring unit, located in the crucible with the melt, there are three electrodes,

10 located at the vertices of a non-sided triangle inscribed in a circle, the diameter of which is 0.55 + 0.15 of the inner di-, crucible meter, concentric with the walls of the crucibles.

The conductivity of the slag is determined by the formula

  44-.

D1

20

where the difference of the constant devices for different pairs of electrodes, determined from the melt with a known electrical conductivity;

25

D2 the difference of the measured interelectrode resistances for the same pairs of electrodes

Claims (2)

in molten slag. The formula shows how the methodological errors caused by the dependence of the processes in the near-electrode layers on the chemical composition of the slag and the electrode, as well as on the characteristics of the measuring current, ensure self-compensation. Fig. 1 is a schematic of the proposed conductometer; in Fig. 2, a crucible with electrodes, top view (holder removed). The device consists of electrodes 1,2 and. 3 and an electrical measuring unit 4. The device is equipped with a switch 5, which allows alternately connecting electrodes 1, 2 and 3 in pairs of 1-2 or 1-3 volts. measuring circuit. Electrodes 1-3 are enclosed in holder b of refractory electrically insulating material — for example, boron aluminide or boron carbonitride. The material of electrodes 1-3 can serve as refractory metals - wolfram, molybdenum, platinum or iridium. As a measuring unit, it is preferable to use a fast acting automatic digital AC bridge. Electrodes 1–3 are placed in molten slag 7, a crucible in a crucible, like electrodes, is made of a refractory metal, such as tungsten, molybdenum, platinum, or iridium. The holder 6 is fixed on the crucible 8 and at the same time serves as its lid, electrodes 1,2 and 3 in the holder b are located along the tops of an unilateral triangle inscribed in a circle with diameter d (0.5 + 0.15) D, where D is the inside diameter of the hole crucible 8. A circle with diameter d is concentric with respect to steaks (hole), crucible 8. The ratio of distances 1 and i, j between electrodes 1,2 and 3 is in the limit (1: 1.5) - (1: 5) , preferably in the range (1: 2) - (1: 3). At the specified electrode location, the smallest methodical error is achieved. In holder 6 electr One or three has an opening 9 through which a thermocouple or probe can be introduced into the crucible 8 to control the level of molten slag 7. The device operates as follows. Before determining the conductivity of the molten slag, the dependence of lА on the level of the melt and the depth of the electrodes 1-3 is established. This is done using a melt with well-known electrical conductivity, usually potassium chloride. Then the crucible 8 is filled with the slag under study, heated, and measured, controlling the temperature of the slag 7 and the depth of the electrodes 1-3 in the molten slag 7. Testing the conductometer showed that it has a simple design and provides a reduction (more than v. 10 times), the systematic measurement error of the electrical conductivity of the slag due to its self-compensation. Apparatus of the Invention A device for measuring the electrical conductivity of a molten ass,. containing electrodes connected to a measuring unit and located in a crucible with a melt, characterized in that, in order to improve measurement accuracy, the number of electrodes is chosen to be three, while the electrodes are located at the vertices of a non-equilateral triangle inscribed in a circle whose diameter is 0, 55 ± 0.1 $ of the inner diameter of the crucible, concentric with the walls of the thiul. Sources of information taken into account in the examination 1.Linchevsky B.V. Metallurgical experiment technique. M., Metallurgists, 1967, p. 2. The same, p.249 (prototype). N 1 and "/" 1TD about g I I I I: h