RU169047U1 - PLASMA PLANT FOR PROCESSING REFRIGERANT SILICATE-CONTAINING MATERIALS - Google Patents

Abstract

The utility model can be used to obtain melts from refractory silicate raw materials in the manufacture of mineral fibers and nanopowders used in the manufacture of building materials. The installation comprises a melting furnace with a water-cooled metal casing. A plasma torch is installed in the lid of the melting furnace through an insulator. A graphite anode is installed at the bottom of the melting furnace. Under the cover of the melting furnace, a metal washer is fixed perpendicular to it on the plasma torch body. The metal washer serves as a protective shield, for which its diameter exceeds the diameter of the plasma torch insulator by at least 1.5 times. The protective screen is continuously cooled by air through a channel made in an insulator located in the lid of the melting furnace. In the middle side of the melting furnace is a drain chute for the exit of the melt. To feed the powdered raw materials into the melting furnace, a screw feeder is used, mounted on the opposite drain chute of the side surface of the body of the melting furnace. The screw feeder is connected to a feed hopper and an electric drive. In the upper part of the melting furnace above the melting zone, a nozzle for removing nanoparticles is additionally fixed. The design of the plasma torch protects the insulator from exposure to high temperature, thereby preventing burnout and destruction, and also eliminates breakdown between the cathode and anode. As a result, the reliability and service life of the plasma system are increased. 3 ill.

Description

The utility model relates to the field of plasma technologies and can be used in the production of building materials from refractory silicate raw materials, and more specifically for producing melts for the manufacture of mineral fibers and nanopowders, which can be used, for example, as modifying additives for building materials.

The prior art installation for producing mineral wool (RU 2270810, С03В 37/06, publ. 02.27.2006), which is used for processing ash and slag waste from thermal power plants into mineral wool using plasma technology. The installation contains a combined plasma reactor with a graphite anode and cathode. The anode is made cylindrical and is a crucible for ash melt. To form a rotating electric arc in the cross section of the reactor chamber, an electromagnetic coil is installed outside the reactor in its middle part. Below, under the plasma reactor, there is a site for blowing cotton wool flowing out of the reactor through a tray. The installation also contains a fiber deposition chamber. This design provides the melting process of ash and slag waste and the process of fiber production in one stage, and also allows you to get a uniform full temperature profile of 1400-1600 K due to the formation in the cross section of the chamber of a rotating electric arc. As a result of direct exposure to the plasma jet, the degree of thermal processing of ash and slag waste increases, and the time for obtaining the melt decreases. However, the use of a cylindrical graphite anode reduces the quality of the melt and the mineral fibers obtained from it due to the "contamination" of the melt with a graphite mass.

Also known is a plant for producing a mineral melt by plasma heating (RU 2355651, С03В 37/04, published May 20, 2009), containing a plasma torch, a circular circular reactor coupled to it in one assembly, a device for supplying a mixture of powder raw materials and air and a module additional melt (melting furnace) with an outlet notch (drain trough) in its lateral part, mounted under the plasma reactor. The body of the plasma reactor is hollow, forming an annular channel for supplying water cooling the reactor. During the operation of the plasma torch, molten particles are deposited on the wall of a water-cooled plasma reactor, forming a skull layer, which, having low thermal conductivity, protects the walls of the reactor from destruction. A device for supplying powdered raw materials and air is made in the form of a cochlea with a spiral channel and mounted under a plasma torch on the plasma reactor housing. The spiral channel is docked with a hole in the reactor vessel. The plasma torch cathode is connected to the negative pole of the DC power source, and a graphite anode is mounted at the bottom of the additional melt module. The module has a partition that divides the module into two zones: the larger - the cooking zone and the smaller - the zone of melt production. The module and the partition are made of refractory material. The uniformity of the heating of the melt is achieved due to the swirling of the incoming stream of raw materials, which increases the time spent in the plasma stream, and the joint heating of the raw materials by the plasma arc and Joule heating due to the electrical conductivity of the melt that accumulates in the module.

The disadvantage of this installation is that during its operation the walls of the refractories wear out and require repair, which requires stopping the melting process and its subsequent repair. In addition, the swirling powder raw material is fed from above into the plasma reactor directly into the plasma jet. In this case, there is a likelihood of fine particles being blown out by a stream of low-temperature plasma and their underfusion, which is also a drawback.

The closest in technical essence is a plasma installation for the production of refractory silicate melt (RU 2503628 C1, C03B 37/04, publ. 10.01.2014). The installation contains a plasma torch, from the bottom of which a melting furnace is installed, which can be made of any section, for example, round. The body of the melting furnace is made hollow with the formation of a water-cooling channel. A drain chute is fixed in the upper side of the melting furnace to exit the melt. A graphite anode is mounted at the bottom of the smelter. A device for supplying powdered raw materials is fixed on the side surface of the melting furnace body opposite to the drain chute. A device for supplying powdered raw materials is made in the form of a screw feeder. The screw feeder is connected directly to the melting zone of the melting furnace, as well as to a loading hopper and an electric drive. Typically, a plasma torch is installed in the furnace lid through insulation. Installation RU 2503628 is relatively simple in design, but has a significant drawback. During the operation of the installation, under the influence of convective flows and radiant energy, the dielectric material, which serves as an insulator of the plasma torch in the furnace lid, is destroyed and covered with an electrically conductive layer of carbon, as a result of which a breakdown occurs between the cathode and anode. The breakdown violates the operation mode of the installation and is dangerous for the operation of the electrodes, as a result of which the reliability and service life of the installation is reduced. In addition, in the installation of the prototype, the melting zone occupies almost the entire volume of the furnace, and the melt is discharged through the drain trough in its upper part. In this design, the installation allows to obtain only melts.

The utility model is aimed at solving a technical problem, which consists in increasing the reliability and service life of a plasma installation by reducing the impact of high energy and temperature on the insulator, as a result of which it does not fade, and at the same time expanding the scope of the installation.

The technical problem is solved as follows.

The plasma installation for processing refractory silicate-containing materials, like the prototype, contains a plasma torch installed through an insulator in the furnace lid and a melting furnace with a metal body, which is hollow with the formation of a water-cooling channel. In the side part, as in the prototype, there is a drain trough for the exit of the melt. A device for supplying powdered raw materials is fixed on the side surface of the melting furnace body opposite to the drain chute. The device for supplying powdered raw materials is made in the form of a screw feeder connected directly to the melting zone of the melting furnace, a loading hopper and an electric drive. A graphite anode is installed at the bottom of the melting furnace.

Unlike the prototype, the inventive plasma installation further comprises a protective shield made in the form of a metal washer mounted perpendicularly to the plasma torch body under the cover of the melting furnace. The diameter of the metal washer exceeds the diameter of the plasma torch insulator by at least 1.5 times. The protective screen is installed with the possibility of continuous cooling by air, for the supply of which an additional channel is made in the insulator. The drain chute for the exit of the melt in the inventive installation, in contrast to the prototype, is located in the middle part of the melting furnace, and in the upper part of the melting furnace above the melting zone, a nozzle for removing nanoparticles is additionally fixed.

An air-cooled shield creates an obstacle to radiant energy and convective flows coming from below and containing conductive graphite particles. It was experimentally established that with a screen diameter equal to or 1.5 times the diameter of the plasma torch insulator, the protective screen prevents burnout and destruction of the insulator and eliminates breakdown between the cathode and anode. The reliability and service life of the plasma system is increased. The location of the melting zone with a drain trough in the middle of the melting furnace and the presence in the upper part of the free zone contribute to the formation of nanoparticles as a result of evaporation and sublimation of the material.

In FIG. 1 presents a General view of the claimed device. In FIG. Figures 2, 3 separately show the installation diagram of the protective screen, front view and bottom view, respectively.

The plasma installation consists of an arc plasmatron 1, a protective screen 2, which is made in the form of a metal washer, insulator 3, water-cooled cover 4, insulator of cover 6, feed device 8, water-cooled metal case 10, graphite anode 12. Silicate melt is indicated by 7, a plasma stream 11, a crucible for collecting melt 9, a pipe for outputting nanoparticles 5. The diameter of the metal washer 2 exceeds the diameter of the insulator by at least 1.5 times.

The device operates as follows.

Preliminarily, the volume of the melting furnace is filled with refractory silicate raw materials. In the cover 4 and the housing 10 serves water. Then, the plasma flow is initiated using the plasma torch 1. Under the influence of high temperature (about 3000-5000 ° C), the raw material begins to melt. After the entire volume of the loaded raw materials passes into the phase of the melt 7, using the feed device 8, an additional volume of powdered raw material is fed into the furnace, which is mixed with the melt and evenly melted in it. As soon as the melt in the furnace reaches the level of the drain trough, it flows into the collecting crucible 9. In this case, under the influence of evaporation and sublimation processes, silica nanoparticles are also formed in the furnace, which in the gas phase follow the collection device through the nozzle 5.

Claims (1)

Plasma installation for processing refractory silicate-containing materials, containing a melting furnace with a metal body, which is hollow with the formation of a water-cooling channel, a plasma torch installed through an insulator in the furnace lid, a drain chute for the melt exit, made in the side of the melting furnace, a device for supplying powdered raw materials mounted on the opposite side of the drain chute of the housing of the melting furnace and made in the form of a screw feeder connected directly but with a melting zone of the melting furnace, a loading hopper and an electric drive, a graphite anode mounted on the bottom of the melting furnace, characterized in that it further comprises a protective shield made in the form of a metal washer mounted perpendicularly to the plasma torch body under the cover of the melting furnace, the diameter the metal washer exceeds the diameter of the insulator in the furnace lid by at least 1.5 times, in addition, the protective screen is installed with the possibility of continuous cooling by air, for supplying which to the isolate D plasmatron formed an additional channel, in addition, the drain chute exit melt located in the middle of the melting furnace and the top of the melting furnace over the melting zone is further secured to manifold output nanoparticles.

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