SU1425239A1 - Method of melting an alloying composition - Google Patents

Abstract

The invention relates to the field of metallurgy, in particular to methods of smelting master alloys based on ferronickel. The aim of the invention is to reduce the loss of molybdenum and tungsten with a reduced content of hydrogen in the ligature. The method of smelting ligatures includes the melting of periodically loaded portions of the mixture from fluxes and nickel-containing wastes, which include iron and nickel hydroxides, in an electric arc furnace. In this case, the charge portions are loaded into the furnace so that the waste with iron and nickel hydroxides is located in the upper layers of each portion. The amount of iron and nickel hydroxides in a portion of the charge is 1–5 May. % Chromium is introduced into portions of the charge 5–15 times more than molybdenum with tungsten. The method of smelting the ligature makes it possible to reduce the waste of molybdenum with tungsten by 70-75% and at the same time to obtain ligatures with a reduced hydrogen content. 2 tab. (I

Description

4ii S

sd tc

Ltd

This invention relates to metallurgy, in particular to methods for smelting ferronickel-based master alloys.

The aim of the invention is to reduce the loss of molybdenum and tungsten with a reduced content of hydrogen in the ligature.

The proposed method of smelting the master alloy includes the melting of periodically loaded portions of the charge from fluxes and nickel-containing wastes, which include molybdenum, tungsten and hydroxides of iron and nickel, in the electric arc furnace, while the batches of the charge are loaded into the furnace so that - iron and nickel cides located in the upper layers of each portion, with the amount of iron and nickel hydroxides in the charge portion being 1-5 May. %, and chromium is 5-15 times more than molybdenum with tungsten.

With this batching of portions, waste containing molybdenum, tungsten and hydroxides of iron and nickel and located in the upper part of each portion, get into the melt after they have reached the temperature of dissociation of all nickel and iron hydroxides into oxides and water. If there are no more than 5% of them in the batch, they will be completely decomposed into oxides and water and the hydrogen will not get into the melt from the waste. When the content in the mixture is more than 5% hydroxide, it does not have time to completely dissociate until the waste enters the liquid metal bath. Thus, IB of the final metal will have an increased hydrogen content.

I If the waste is contained in the lower portion of the | portion, then it will get into the melt too early, even without warming up to the dissociation temperatures of all the hydroxides, which will lead to contamination of the melt with hydrogen. With the introduction of less than 1% of iron hydroxides 1 and nickel in the composition of the portion in the mixture use a small amount of waste (less than 10%) containing these hydroxides. The involvement of these wastes in smelting requires their preliminary preparation at a special site (sorting, cutting, briquetting, etc.). This becomes economically inexpedient if they are used in a charge of less than 10%.

In order to prevent molybdenum and tungsten from being oxidized by iron and nickel oxides formed after decomposition of hydroxides and entering the melt together with the waste containing them, chromium containing waste is added to the melt so that chromium in the charge portions It was not less than 5 times more than molybdenum With tungsten. In this case, only chromium is predominantly oxidized in the melt. If chromium is more than 15 times greater than molybdenum with tungsten, then chromium waste becomes so refractory that it is

is melted later than waste with molybdenum and tungsten m, and chromium does not fulfill its protective role in the melt. If the chromium is less than 4%, molybdenum and tungsten begin to oxidize vigorously due to the lack of chromium in the melt. Thus, at non-optimal chromium content in waste products, the loss of molybdenum and tungsten increases significantly.

The results of the experimental heats ligatures are given in table. one.

Example. In a DSP-6N2 furnace, a series of 6-ton iron-based melts was made, in May. %: molybdenum 0.8-1.0; tungsten 0.2-0.3; chromium 5.0-10.0; impurities

r the rest (from waste containing nickel, battery scrap, trimmings, chips). Melting lead by periodic loading into the furnace portions of waste weighing 200-300 kg. Each subsequent batch is loaded as the previous one melts, but not

0 to an open bath to avoid metal spills. In smelting 11 (Table 1), a 30-minute holding of the melt is obtained according to the known technology for the removal of hydrogen after complete melting. Wherein

The loss of tungsten and molybdenum is 80%. On the remaining swimming trunks excerpt completely excluded.

In smelting, 3 battery waste with hydroxides is given in the lower layer of each

Q portions. You get a ligature with a high content of hydrogen. In swimming trunks 2,2,4-10 battery waste is given in the upper layer of each portion. It was established that with the introduction of more than 5% iron and nickel hydroxides with waste, the content of water 5 in the ligature is two times higher than in the case when the hydroxides are less than 5%. If in the first case, in smelting 4, the hydrogen content in the metal is 2.0X10%, in the second case, in the melts 1-2, 5-10 its content does not exceed 1.1X10%. Swimming trunks

0 1-5,7,10, when chromium in the waste is 5-15 times more than molybdenum with tungsten, the waste of the latter is two times lower than with other ratios (smelting 6, 8, 9). Smelting 12 is not economically viable because

less than 9% of accumulator wastes are involved in the remelting of hydroxides. Such a restriction does not allow to fully engage in the remelting all waste of this type formed in the national household.

0 The chemical composition of the obtained ligatures is given in table. 2

The proposed method has the following technical and economic advantages: involvement of waste containing iron and nickel hydroxides in overproduction, with simultaneous preservation of molybdenum and tungsten in the composition of the produced master alloys with reduced hydrogen content; 75% reduction of molybdenum carbon loss with tungsten.

Claims (1)

Invention Formula The method of melting the master alloy, including the melting of periodically charged portions of the mixture of fluxes and nickel-containing wastes in the arc steel-smelting furnace, which include molybdenum, iron hydroxides and nickel hydroxides, in order to reduce molybdenum and tungsten carbon monoxide with reduced content of hydrogen in the ligature, chromium in an amount 5-15 times more than molybdenum and tungsten is introduced into the mixture, and the charge portions are loaded into the furnace with waste disposition with iron and nickel hydroxides in the upper layers of each portion while the amount of iron and nickel hydroxides per portion of the mixture is 1-5 May. /about The content in portions of the mixture, wt.% No. 1 Fe (OH), Mo + U CrHydrocks Ni (OH) 5 + Fe 10 10 10 10 15 18 five 4 4 5.0 1.0 1.0 5.5 4.0 4.0 5.0 5.0 1.0 1.0 5.5 12 ten 0.9 Spreadsheets not % H x lO in LIGZ-tour Ugar Mo + W, OTH,% Indications 1.1 1.0 2.1 2.0 1.0 1.0 1.1 1, 1 1.0 1.0 1, 0 1.0 5 5 5 five 4 s five 10 10 A 80 Hydroxide wastes are given in the lower layers of each batch. Hydroxide wastes are mixed with other wastes. After the complete melting of the mixture gives a 30-minute melt exposure (a known method) Recycling waste with hydroxides is not economically feasible. table 2 Continuation of table 2