SU1723166A1 - Process for refining copper and copper base alloys - Google Patents

Abstract

The invention relates to non-ferrous metallurgy and can be used in the refining of copper and alloys based on it. The purpose of the invention is to reduce metal losses, improve the quality of the metal and reduce the consumption of refining materials due to the continuous sublimation of sodium compounds. The method of refining copper and alloys based on it involves feeding the sodium compound and the reducing agent to the surface of the metal melt. Initially, a reducing compound of sodium is supplied to the surface of the metal melt, it is held until the temperature of the metal melt is reached, and the sodium compound is continuously fed at a rate of 0.5-4.0 kg / min.

Description

The invention relates to color IU. tallurgy, can be used in the refining of copper and copper-based alloys .; ; . . ;,.:,; ;. Y: O -.- v ;;

There is a known method of refining copper and copper-based alloys, in particular copper-nickel alloys, including distance. no slag from the surface of the metal melt and the supply of sodium compounds, in particular soda, in a uniform layer over the entire surface of the metal melt. :

The closest to the proposed method is the refining of copper and copper-based alloys, in particular, copper-nickel alloys, including mixing sodium compounds, in particular soda with the charge, melting this mixture, settling before separation into two layers — a layer of metal melt and slag layer, slag removal and the supply of the reducing agent, in particular charcoal, to the clean surface of the metal melt. The disadvantages of the known methods are as follows: 1) a significant loss of metal with slag, since the melt layer of the sodium compound on the surface of the metal melt due to its viscosity is created during the refining process, conditions for depositing and accumulating in it. and then removal with the slag of the metal in a free and bound state; 2) insufficiently deep refining of metal from harmful impurities and nonmetallic inclusions, since the melt layer of the sodium compound on the surface of the metal melt, due to its viscosity, makes it difficult to remove the harmful impurities and nonmetallic inclusions from the metal melt and thus the utilization rate of the refining capabilities of the compounds on VI

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three, in particular soda, in the refining of copper and copper-based alloys, in particular copper-nickel alloys, by a known method is very low; 3) high consumption of refining materials, since, according to the known method, they should cover the entire surface of the metal melt with an even thick layer; 4) high refractory consumption, since the layer of molten sodium compounds, in particular soda, due to its high chemical aggressiveness, eats away at the lining, thus reducing the duration of operation; 5) the rapid overgrowth of the bath of the melting unit, and since the interaction of the melt of the sodium compound, in particular soda, with the casing of the lining leads to the formation of wall buildup, which reduces the useful section of the bath of the melting unit.

The purpose of the invention is to reduce metal losses, improve the quality of the metal and reduce the consumption of refining materials by continuous sublimation of sodium compounds.

The goal is achieved according to the method of refining copper and alloys based on it, which involves supplying sodium compounds and a reducing agent to the surface of the metal melt, in which the reducing agent of the sodium compound is initially supplied to the surface of the metal melt, is maintained until the temperature of the metal melt is reached, and sodium compounds are continuously fed. speed of 0.5-4.0 kg / min.

The essence of the invention is as follows.

A reducing agent is fed to the surface of the metal melt, kept up to the temperature of the metal melt, and a continuous supply of sodium compounds is started at a rate of 0.5-0.4 kg / min.

The feed rate of the sodium compound in this range ensures its continuous sublimation and thus excludes the possibility of the formation of a layer of molten sodium compounds on the surface of the metal melt.

As a result, the sodium compound interacts exclusively with the reducing agent, and the metal melt and the lining - only with the restorer products. This makes it possible to reduce metal losses, improve the quality of the metal and reduce the consumption of refining materials. In addition, the lining life is increased.

The principal difference of the proposed method of continuous supply of sodium compounds in a given range of feed rates to the surface of a metal melt covered with a layer of red-hot reducing agent, from a known method, while simultaneously supplying the required number of sodium compounds to the clean surface of the metal melt, the metal melt interacts with the proposed method with a gas phase saturated with sodium vapor. In the known method, the metal melt interacts only with the melt of the sodium compound, which isolates it from contact with the furnace atmosphere.

Sodium compounds are used to refine copper and copper-based alloys, since it has been found that sodium can be recovered from any of them. To do this, it is necessary for each particular molten metal to select the appropriate sodium compound and restore it, and the temperature of the metal melt must ensure optimal conditions for the reduction reaction to proceed. At the same timeTemperature

the following reactions

№2C03 + + 3COt1000 ° C

4NOON + 2С- №2CO3 + + 2Na + 2H2f + CQf900 ° C

N32B407 + 7C- 2Na + 7COF + 4B 950 ° C 2NaCI + CaO + C- 2Na + + CaCl2 + CO 950 ° C

2Na + S - Na2Sf 2Na + - NaaS2f MazR

As can be seen from the schemes provided for the example, as a result of such processes, sodium is recovered from the compounds and in the furnace atmosphere, near the copper melt or alloys based on it, is in the form of steam / saturation of the furnace atmosphere, ensuring its high refining potential. In addition, during the refining process, the reducing atmosphere saturated with sodium furnace atmosphere also performs a coating function, excluding oxidation of the surface of the metal melt with air and the formation of slag.

Metallic sodium is known to be a fairly effective means for refining copper and its alloys from various harmful impurities and non-metallic inclusions.

However, its use due to the low boiling point (877.5 ° C) is impractical, since at the melt temperature

Most of the sodium will escape to the atmosphere without reacting with the metal melt, and using it at high costs is unsafe.

Thus, the proposed method of refining copper and alloys based on it provides: the elimination of metal loss from the slag and metal contamination by nonmetallic inclusions, since in the created conditions on the surface of the metal melt the formation of the slag phase is impossible during the refining process.

Part of the slag formed before the refining agent is loaded is restored as a result of interaction with the reducing agent, activated sodium compounds, the products of the reduction are either distilled into the furnace atmosphere, the libre is returned to the metal (zinc, copper, nickel).

Slag formation in the process of refining in the conditions of isolating the surface of a metal melt with a layer of reducing agent and a furnace atmosphere saturated with sodium vapor, which is a strong reducing agent, is practically impossible.

Thus, the absence of slag eliminates the loss of metal with slag and the contamination of the metal with slag inclusions,

The method provides deep refining of the metal melt from harmful impurities, for example: sulfur, phosphorus, carbon, etc., which are removed from the metal melt into the furnace atmosphere of steam. -1. mi rub.

According to the method, the consumption of reducing agent and sodium compounds is reduced due to the increased yield of free sodium and the shortening of refining time, while the reducing agent is used repeatedly, reducing the consumption of refractories as a result of eliminating the interaction of the lining with the melt of sodium compounds and thus their erosion and formation of walling.

The sodium compounds are fed at a rate of 0.5-4.0 kg / min on the assumption that it will be equal to the sublimation rate.

When the feed rate of the sodium compound is less than 0.5 kg / min, the sodium vapor content in the furnace atmosphere will be insufficient for the process of refining the molten metal. All of the reduced sodium is consumed in the interaction with the furnace atmosphere.

At a feed rate of a compound of three more than 4 kg / min, the principle of continuous sublimation is violated. The fed sodium compound does not have time to sublimate and accumulate on the surface of the metal. then melt in the form of a liquid phase .. The process proceeds practically by a known method. Slag is formed, the fouling is corroded, the refining is slowed down. The main advantages of the proposed method are lost.

The feed rate of the sodium compound in the order of 0.5-2.0 kg / min is recommended mainly for the treatment of copper and relatively low-melting copper-based alloys (brass, bronze) with a pl. 1000-1100 ° C. As a sodium compound, a borax (MaaEMO) is preferable, as a reducing agent is an electrode fight.

The feed rate of the sodium compound is in the order of 2.0-4.0 kg / min. Preferred for the treatment of copper-nickel alloys. It is best to use soda with a melting point of about 4 times as a sodium compound. 1200-1 ZOR ° C (MaAS0). As a reductant, electrode combat, coke. .. When the reducing agent of sodium compounds is heated below the temperature of the metal melt, the reduction process is not sufficiently intense, and the sodium concentration will not be sufficient for the process of refining the metallic melt. When the reducing agent is heated above the temperature of the metal melt, the reduction process proceeds too intensively and most of the sodium vapor will

5 to be distilled outside the furnace atmosphere without reacting with the metal melt, the efficiency of the refining process is reduced,

Example 1. In channel induction

0 ILK-1.6 type furnaces melted 3,000 kg of L-63 brass brass. 50 kg of electrode booster was loaded onto the melt surface for 15 minutes, then heated to the temperature of the metallic melt (1100 ° С) and

5 for 30 minutes a borax was applied at a rate of 0.5 kg / min. After stopping the borax, the metal was poured, /

When smelting, there is no loss of metal with slag. Sulfur content in the melt

0 reduced to 0.003% (original content 0.02%). The content of non-metallic inclusions is up to 0.003% (initial 0.9%). The consumption of the reducing agent is 9 kg for smelting, the consumption of borax is 15 kg for smelting.

5 The electrode temperature was determined using an optical pyrometer. . With me p2. In the channel induction furnace of type I LK-1.6, 3000 kg of copper-nickel alloy of the MNC 15-20 were melted. On the surface of the metal melt downloaded

50 kg of electrode boil and held for 15 minutes letting it heat up to the temperature of the metal melt (1200 ° C). Then, water was supplied at a rate of 2 kg / min for 7.5 minutes, then the metal was poured.

Losses of metal with slag are absent. The sulfur content is reduced to 0.004% (initial 0.02%), the content of non-metallic inclusions is reduced to 0.003% (initial 0.7%), the consumption of the reducing agent is 5 kg for smelting, the consumption of soda is 15 kg for smelting.

Example 3. In a channel induction furnace of the type ILK-1.6, 3000 kg of MNZhMts 30-1-1 copper-nickel alloy were melted. 30 kg of coke was loaded onto the surface of the metal melt, held for 15 minutes, allowing it to heat up to the temperature of the metal melt (1300 ° C) and soda was supplied at a rate of 4 kg / min for 3.7 minutes, then the metal was poured.

Losses of metal with slag are absent. The sulfur content is reduced to 0.004% (initial 0.02%), the content of non-metallic inclusions - to 0.002% (initial 0.9%).

The consumption of the reducing agent is 6 kg per smelting, the consumption of soda 15 kg per smelting.

The test results for the proposed, well-known method are shown in the table.

As can be seen from the above data, the proposed method provides deeper melt refining from sulfur, non-metallic inclusions, a sharp decrease in metal losses from the slag, while reducing the consumption of refining materials.

Claims (1)

Claims The method of refining copper and alloys based on it, including the supply of sodium compounds and a reducing agent to the surface of a metal melt, is also distinguished by the fact that, in order to reduce metal losses, improve the quality of the metal and reduce the consumption of refined materials the sodium compounds, initially on the surface of the metal melt, are fed a reducing agent; the sodium compounds sustain it until the temperature of the metal melt is reached and the compound is continuously fed and sodium at a rate 0.5-4.0 kg / min. -four to with about O5