SU846591A1 - Unit for metal refining - Google Patents

Description

(54) DEVICE FOR METAL REFINING

The invention relates to non-ferrous metallurgy, in particular to the field of CASTING and the refining of aluminum and its alloys. The refining of light alloys from non-metallic inclusions and gas is carried out in various ways on various devices: filtration through solid and liquid filters; vacuuming in furnaces, ladles and in a stream; purging with inert gases, etc. A device for refining liquid metal is known. It consists of tubular filter elements. Meta filtration is provided by flowing it through the walls of filter elements made of porous ceramic material LI. However, this device does not ensure the degassing of the melt, does not cause fine impurities, and the service life of the filter elements is limited. A device for refining aluminum alloys, consisting of a tank in which two gas-permeable elements are immersed, is known. The vacuum system G2 is connected to the inside of the elements. This device does not provide CLEANING metapl. From non-metallic impurities, during long-term operation the filters are clogged with fine impurities adsorbed on the gaseous bubbles and are OVERCOMMONENT and regeneration of such filters is impossible. The filtering process is ideally stationary and therefore periodic. A device for refining metals is known, including hollow gas permeability: elements that are connected to a vacuum system and a compressed gas supply line. The elements are periodically flushed with an inert gas. The disadvantage of the device lies in the fact that the refining process is stationary and not the entire volume of the metal is subjected to vacuum. Cleaning from solid non-metallic impurities does not occur at all. When the element is purged with compressed gas, fine impurities adsorbed on the surface of the element are returned back to the melt. Thus, the final goal of refining the purification of both gas and solid non-metallic impurities is not achieved.

The purpose of the invention is to increase the efficiency of refining through the complex cleaning of the melt from gas and solid non-metallic inclusions and to ensure the continuity of the process.

The goal is achieved by the fact that in a device for refining metals, including hollow gas-permeable elements connected to a vacuum system and a compressed gas supply pipeline, the elements are installed with a gap between them not more than 2 and form internal removable and external stationary chambers, and facing the refined metal the surface of the elements forming the stationary chamber is gas-tight,

The elements are installed in a checkerboard pattern.

FIG. 1 shows a device installed in a casting chute, side cut; in fig. 2 - the same, top view.

The device consists of hollow gas-permeable elements 1 arranged in two rows, the inner row forms a removable metal refining chamber 2 where the metal is fed, and the outer row forms a stationary chamber 3. The gas-permeable elements 1 are connected to the vacuum system 4 by pipeline 5 gas through valves. Gas permeable elements mounted on pdone b. The number of hollow gas-permeable elements and the gap between them is selected depending on the type of metal and the number of non-metallic inclusions and the gas contained in it. The elements can be made in the form of cylinders or in other configurations, for example, rectangular.

The device works as follows.

Preheated to 400500 With the device is placed in a foundry chute. A liquid metal is continuously supplied from the mixer to the internal removable KeiMepy 2, the vacuum system 4 is switched on and the hollow gas-permeable elements 1 of both chambers are connected to it. Didek metal flowed into the gap between the elements (for example.

0.18

150

Aluminum

0.30

230

Aluminum

graphite), in which discharges of the order of 1-10 mm Hg are created, is degassed. Large inclusions, the dimensions of which exceed the size of the gap, are retained in the device, and the fine dispersed are deposited on the walls of hollow gas-permeable elements due to the floating effect of the directional gas flow evacuated from the metal. Fine impurities adsorbed on the walls of the elements are retained on them due to the significant difference in pressure between the metal layer and the gas-permeable elements. As the impurities accumulate on the pallet B of the inner removable chamber 2 and the pores of the gas-permeable elements are clogged, which is indicated by an increase in the degree of discharge in the vacuum system, the evacuation is switched off and compressed gas is supplied through pipeline 5. The compressed gas blows through the pores of the elements, after which the inner chamber 2 is removed and the pan of the chamber is cleaned of impurities. The refining of the metal at this time is carried out by the external chamber 3. After cleaning, the removable chamber 2 is inserted into the stationary chamber and connected to the vacuum system and the compressed gas supply system. The outer surface of the elements forming the stationary chamber is made gas-tight to prevent contamination of the refined metal when the elements are purged with compressed gas.

For example, a lined box preheated to 500 ° C is installed in a lined container with a drain hole, one of the walls of which is made of eight hollow elements (graphite tubes 30 mm in diameter with a wall thickness of 5 mm). The tubes are installed with a gap of 2 mm relative to each other, the lower ends of the tubes are fixed in the lining of the box, and the upper ends in the manifold. A manifold is introduced into the collector, to which a vacuum system and a gas supply system are connected. Vacuum is provided by a VN-3 fore pump.

Refined molten aluminum and silumin. Volumes of heats - 25-300 kg of melt with continuous refining.

The results of the experiments are given in the table.

0,002

0,006

0.08

0,004

0,0}. .

0.08

Claims (2)

Claim This device allows you to clean metal from solid non-metallic inclusions, to degass the metal during the filtration process, to reuse the elements, since their periodic blowing with compressed gas eliminates the filling of pores of hollow elements with non-metallic inclusions and metal, and to carry out a continuous refining process. 1. A device for refining metals, including hollow gas-permeable elements connected to a vacuum system and a compressed gas supply pipe, characterized in that, in order to improve the refining efficiency due to the complex cleaning of the melt from gas and solid non-metallic inclusions and ensuring the continuity of the process, the elements are installed with a gap between them of no more than 2 mm, the formation of internal removable and external stationary cameras, and the surface of the elements facing the refined metal, the image stationary guides chamber formed gastight. 2. The device according to claim 1, about t l and the fact that the elements are installed in a checkerboard pattern.