RU2524408C1 - Lining of retorts for production of metals and alloys by metal-thermal reducing fusion - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: proposed method comprises fitting of detachable insert in retort with clearance between return wall and insert. Lining material is filled in clearance between insert and return wall to make return lining. Insert is withdrawn to fit return in place with made lining into furnace. Note here that liquid slag of previous smelting is used as retort lining tapped from the furnace via tap hole into the other, specially prepared retort outside the furnace. Retort with discharged slag is withdrawn from the furnace and lined with application of liquid slag of previous melting for next melting in the furnace for metal-thermal reducing fusion. Insert can be composed of several parts.

EFFECT: shortened melting cycle, controlled lining wall quality.

2 cl

Description

The invention relates to metallurgy associated with the production of rare metals and alloys, for example, for producing high-energy Nd-Fe-B magnets, by the method of metallothermal reduction melting.

A known apparatus for metallothermal production of metals and alloys [RU No. 2059007, C22B 5/04; publ. 04/27/1996, bull. No. 13], consisting of a hopper with a loading pipe and a housing with a cooling jacket. The apparatus is equipped with a hollow punch located on the lower end of the loading pipe with an end part, which is made in the form of a tube removed inside the loading pipe, and an ignition device, the loading pipe is made with the possibility of reciprocating movement, and the housing with a movable bottom, while the ignition device is placed in the cork, and the side wall of the lower part of the body is made with a semicircular slot to remove the product. After loading the apparatus with a charge in it, a reaction of calcium thermal reduction is initiated. The metal formed during the reaction is formed in the lower part of the crucible, and the slag melt is located above the metal. After melting, without waiting for the slag to solidify (crystallize), a punch is lowered into it and, thus, a crucible is formed from the slag of the previous melting with the specified geometric dimensions for the next melting. The crucible is cooled, loaded with a charge and the melting process is repeated.

The disadvantage of the apparatus is the inability to use it for large-scale melting (ingot diameter of 1 meter or more and height 1 meter or more) due to the inaccessibility of quality control of the walls of the formed crucible (with a large diameter of the lining, through holes, sinks and other defects in the cylindrical and bottom walls). In addition, the large dimensions of the punch increase its mass and complicate the mechanisms for raising and lowering it.

A known method of lining retorts for producing metals by metallothermal reduction melting [RU No. 2034058, C22B 5/04, C22B 34/00, F27D 1/16; publ. 04/30/1995], adopted as a prototype. The method includes preparing the lining powder, installing a cylindrical removable insert on the metal receiver, filling the gap between the retort body and the removable lining powder insert, loading the reaction charge inside the insert and removing the insert from the retort, the insert being wrapped with paper before being inserted into the retort and left in the retort after extract the insert, and as the powder of the lining use pre-ground sinter obtained from the previous recovery smelting.

The disadvantage of this method is the presence of additional operations for cooling and grinding the cooled slag cake obtained from the previous reduction smelting.

The objective of the invention is to simplify the manufacturing technology of crucibles of a given quality, designed for large-capacity melting.

The problem is solved in that the method of lining retorts for producing metals and alloys by metal thermal reduction smelting involves installing a removable insert with a gap in the tank for melting, loading the lining into the gap and removing the insert, and the lining is liquid slag obtained from the previous metallothermic melting, and an insert may consist of several parts.

The essence of the method of lining retorts is as follows. In a furnace for metallothermal reduction, metal or alloy is melted in a vessel. For the first heat, the container is lined with a powder material in any known manner, for example, described in the prototype. After melting, the formed metal or alloy is poured through a hole in the bottom into a metal receiver, and slag is removed from the apparatus through a special notch to another container outside the apparatus that is identical to that in the furnace. A tank outside the furnace is preliminarily prepared for receiving slag. A removable insert with the required clearance along the cylindrical wall and the bottom is coaxially inserted into it. The outer surface of the removable insert may be any necessary to obtain the internal shape of the lining, because this form may affect the quality of the heat. In the process of pouring slag into the gap between the removable insert and the container, due to the sufficient dimensions of the insert, it is possible to monitor the quality of the resulting lining, for example by “transillumination” by ultrasound. If a defect is detected (for example, a gas bubble), it can be removed by local vibration or by tapping the wall of the insert and (or) the wall of the container. Liquid slag will squeeze out the resulting gas bubble. After the lining has cooled to the crystallization temperature of the slag, the insert is removed from the container; to facilitate this operation, the insert can be made of several parts.

The vessel from which the slag was drained is removed from the furnace and lined for the next melting, and the vessel with the resulting lining is loaded with a charge and installed in a furnace for metallothermic reduction using a lifting mechanism.

Thus, using the proposed method of lining retorts, the time of the melting production cycle is reduced due to the absence of cooling and extraction stages of slag from the tank for melting and its crushing. Slag filling takes place in a fairly short time, and the quality of the lining walls is controlled at the stage of slag pouring with the possibility of correcting possible defects.

Claims (2)

1. A method of lining a retort for metallothermal smelting of metals and alloys in a furnace, including installing a removable insert in the retort with a gap between the wall of the retort and the insert, loading the lining material in the gap between the insert and the wall of the retort to obtain a lining of the retort, removing the insert and installing the retort with obtained by lining in the furnace, while the slag from the previous heat is used as the lining of the retort, which is removed from the furnace through a notch to another retort outside the furnace, previously prepared data for its reception, and the retort, from which the slag was drained, is removed from the furnace and lined using liquid slag from the previous melting for subsequent melting in the furnace for metallothermic reduction. 2. The method according to claim 1, characterized in that the insert is made of several parts.