DE2133417C3 - Process for the production of aluminum-silicon alloys - Google Patents

Description

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The invention relates to a method of manufacture of aluminum-silicon alloys by adding from the batch that consists of silica-alumina material and one of the reducing carbon supplying mixture of petroleum coke and another type of coal is formed using a binder or briquette and the batch in this form is implemented in an electric furnace, after which alloy and slag are separated from each other.

In the DT-PS 902 678 a process for the production of aluminum-silicon alloys is carried out Reduction of the oxidic raw materials briquetted with carbonaceous reducing agents in the electric Furnace described in which briquettes made of clay, quartz sand and coal pressure extract are used will. In these briquettes, part of the hard coal pressure extract can be replaced by extract coke and / or another low-ash carbonaceous reducing agent, such as. B. charcoal, be replaced. In this patent also states that the manufacture of aluminum-silicon alloys in the Way can be done that alumina and silicic acid-containing raw materials such. B. kaolin plus an additive of alumina, with the reducing carbon, such as. B. a mixture of charcoal and petroleum coke, briquetted and these briquettes together with lumpy quartz and also lumpy charcoal in the electric Arc furnace can be reduced.

Those used in the known processes for the production of aluminum-silicon alloys Batches have the following properties:

The batch obtained using charcoal as the sole reducing agent has Insufficient briquetting ability, requires the introduction of larger amounts of binder and complicates the technological transport scheme of the preparation of the batch as a result of the formation of larger ones Lots of greetings and broken briquettes. A major disadvantage of such a batch is that the Charcoal is expensive and in short supply.

If one uses batches that only use coal with a lower level of metamorphosis as a reducing agent are obtained, the aluminum-silicon alloy obtained becomes considerably iron and titanium contaminated, thereby reducing the yield of marketable product in the subsequent metallurgical process Processing of the primary alloy is adversely affected.

Batches that can be made thinner using charcoal or bituminous coal as a reducing agent without introducing any emaciation carbonaceous materials obtained, have the disadvantage that their use in the Production of aluminum-silicon alloys in industrial electric furnaces is severely limited.

Batches of the composition mentioned are characterized by poor sinterability, which means it leads to spontaneous collapse in industrial electric furnaces with a high specific power at the electrodes the batch arrives and the characteristic values of the furnace operation deteriorate significantly.

The use of sulnt-alcoholic storage calcium-based binder leads to contamination of the resulting alloy with calcium increasing slag formation when melting the batch and lowering the yield of the alloys when refining non-metallic additions.

In the OE-PS 119 307 is a method of extraction of aluminum and aluminum alloys through the reduction of aluminum oxide or those containing aluminum Material described in the electric furnace in which the raw material containing alumina is used with intimately mixed carbon-containing reducing agent in briquette form, only part of the reducing agent required for the reduction of the briquetted oxide is also briquetted is, while the other part in lumpy or gritty form of the charge is mixed loosely will. This patent also states that known processes and binders are used for briquetting Can be used, such as pitch, sulphite liquor, tar, lime, clay and water. More details on the type of sulphite waste liquor are not included in this patent specification and it is added that the sulphite waste liquor is used as a binder for the briquetting of only part of the batch, while Additional ingredients (coke and calcium sulfide) are then added to this briquetted part will.

The use of lampblack as a reducing agent is general in »Ullmanns Enzyklopadie der Technical Chemistry «Volume 14, 1963, p. 806 given, but with a reference to what is described here Procedure is not included.

The object of the present invention is to- The batch for the production of aluminum silage rounds To eliminate the above-described deficiency zium alloys, a mixture of the following is used Process for the production of aluminum-based grinding materials: silica-alumina-containing Specify silicon alloys with the optimal raw material, carbonaceous reducing agent, binding sinterability and gas permeability on the gout of the 5 means and additives in the form of chlorides or Ore reduction electric furnace with uniform low fluorides of the alkali and / or alkaline earth metals, where go of the batch, reduced slag formation in the mixture through briquetting or granulation Kiln and increase the yield in refining made lumpy and reduced to a residual content the aluminum-silicon alloy ensures humidity of no more than 1.0% is dried, are. In the manufactured alloy, the content should be. Kaoan Iron and titanium may be reduced. line, kyanite, thistle sillimanite and other pebble

To solve this problem, materials containing earth and alumina are used at the beginning, given method according to the invention thereby at most 0.7 to 1.0% iron and at most 0.6 to indicates that the mixture contains 0.7% titanium as a binder for the granulation. As a carbon or briquetting of the charge alcoholic sulphite-containing reducing agent, a mixture is used waste liquor based on the cations of sodium, of petroleum or pitch coci mn soot with a magnesium content or ammonium is used that as nis in relation to the non-volatile carbon in the second type of carbon soot is used and that earth-mentioned materials νυη 3.0 to 0.5: 1.0 what the Oil coke and carbon black are used in an amount when introduced into the batch of 25 to 67% carbon black which is the percentage of non-volatile carbon 96 to 20 total non-volatile carbon content in the 100 ° "corresponds to the stoichiometrically required amount loading charge.

carries and also the ratio of non-volatile. Sulphite-alcoholic binders are used

Carbon from petroleum coke and soot in the waste liquor area based on the cations of sodium,

3.0: 1 to 0.5: 1. Magnesium or ammonium. In addition, you bet

It is advantageous to add chlorides and fluorides to reduce the iron and titanium content in the

the alkali and alkaline earth metals individually or collectively alloy in the process of ore reduction melting

sam in an amount of 3% of the total weight of the batch chlorides and fluorides of the alkali and /

To use batch. or alkaline earth metals too. The named components

The present invention ensures that the batch is milled to advantage after the previous one Way the production of aluminum-silicon-30 given proportions dosed, mixed and the Alloys containing 55 to 68% aluminum and 44 to crumbling (by granulating or briquetting) Contains 31% silicon and is further subject to construction. The crumbled batch is up to or wrought alloys can be processed. Achieving a residual moisture content of Also in the production of silicon aluminum, which is dried at most 1% and ends up in the ore for the deoxidation of steel or as a reduction electric furnace.

Means for metallothermal processes to manufacture Depending on the specific electrical

different metals are used, depends on the performance of the furnace, based on the cross-sectional area

Alloy electrodes manufactured using the method according to the invention, one chooses the necessary weight

tion suitable. ratio of carbonaceous reducing agents

In addition, the invention can also be used in other 40 in the batch while maintaining a summary

neighboring electrothermal application area of non-volatile carbon content of the batch

chen, e.g. in the production of technical from 96 to 100% of the stoichiometric amount required for

Silicon, silicon calcium and other low-iron require the oxidation of the oxides of the charge to metals.

Ferro alloys, can be used. that is.

The alcoholic sulfite used as a binder 45 Examples of the implementation of waste liquor based on the cations of sodium of the invention are given below.
Magnesium or ammonium, which individually together _R. · 1 1
may be present causes a lowering of the example
Calcium admixtures in the batch, which favor the slag The batch is calculated on a content of kenbildung and the yield of refined 5 ° 60% of aluminum in the alloy, which is produced in an ore alloy with regard to the main constituent reduction furnace. The pieces together diminished. setting of the batch, in kilograms: kaolin 100.0;

The use of sodium chloride in raffi clay 38.84; Carbon black 22.75; Petroleum coke 24.55; Tie of aluminum-silicon alloys is at average 9.8.

known (cf. »Ullmanns Fnzyklopadie der tech- 55 In the example given, the ratio is

nischen Chemie ", Volume 3, 1953, p. 352). between the non-volatile content of the batch

In the present process, the use of carbon black and petroleum coke 1: 1 does what the formation of chlorides and fluorides of the alkali and / introduction into the batch of carbon black in an amount of or alkaline earth metals in the specified amount which lower 50% of the total content of non-volatile coal the content of the raw melt of iron and 60 material in the batch corresponds to that with the soot and Titanium impurities in the process of ore reduction petroleum coke is introduced.

melting, which makes it possible to further The above composition of the batch

Facilitating technological work operations and making it possible to maintain stable operating conditions of the

the yield of end products (cast and construction electric furnace with a specific electrical power

tion levels as well as silumines). 65 performance, based on the cross-sectional area of the elec-

In the following, the invention is carried out by means of a trench, in the range from 3000 to 3500 kW / m *

detailed description of examples for their guarantee. It is a content of the diluted

Implementation explained in more detail. Alloy of iron up to 0.47% and of titanium up to 0.14%

ensured while the yield in the filtration of such alloys makes up at least 94%.

Example 2

The batch is calculated based on an aluminum content of 60% in the alloy. The composition of the batch, in kilograms: kaolin 100.0; Alumina 38.84; Carbon black 15.05; Petroleum coke 32.80; binder 9.84; Total weight 196.53 kg.

In the said batch, the ratio between the petroleum coke and the soot is 2.0: 1.0, what a ratio of 67:33 based on the weight of non-volatile carbon in the mixture of Reducing agent corresponds.

The stated ratio between the reducing agents in the batch makes it possible to ensure stable operating conditions of the electric furnace with high (over 3500 kW / m ² ) specific electrical conduction on the electrodes. The iron content of such reducing agents in the diluted alloy is up to 0.52% and of titanium up to 0.15%. The yield of the finished product when filtering such alloys is at least 93.2%.

Example 3

The batch is calculated for the production of an alloy that contains 60% aluminum. The composition of the batch, in kilograms: kyanite concentrate 100; Carbon black 15.6; Petroleum coke 16.84; sulfite-alcoholic Waste liquor based on sodium cations 7.0.

The alloy obtained from such a batch contains 0.5 absolute percent less calcium than the alloy obtained from the batch using the binder based on calcium cations. Accordingly, the yield of refining the primary alloy obtained from one increases such batch, by 1.5%.

Example 4

The batch is calculated for the production of an alloy that contains 60% aluminum, a) The Zv.- composition of the batch, in kilograms: Kyanite concentrate 100; Carbon black 15.6; Petroleum coke 16.84; Binder 7.0; Sodium fluoride 4.6. b) The composition of the batch, in kilograms: Kyanite concentrate 100.0; Carbon black 15.6; Petroleum coke 16.84; Binder 7.0;

ao sodium chloride 4.6.

The aluminum-silicon alloy obtained from the batches mentioned contains 15 to 25 relative percent less iron and titanium additions than the alloy obtained from similar batches, but without introducing chlorides and fluorides into the batch. A lowering of the specific consumption of electricity and input materials per 11 refined alloy of 1.5 to 2% achieved.

The invention proposes a batch which makes it possible to operate the furnace at to stabilize increased performance in order to reduce the calcium content of the alloy by 0.5 absolute percent, the iron and titanium content of the alloy obtained by both using a purer carbon-containing reducing agent as well as by introducing additives of chlorides or Lower fluorides of the alkali and alkaline earth metals in the batch.

The result of the improvements mentioned is a reduction in the specific electricity consumption per ton Finished product, increasing the yield when refining the primary alloy by reducing it the content of the alloy in admixtures of calcium and the increase in the yield in the Filtration of the diluted alloy by reducing the content of the alloy in admixtures of Iron and titanium.

Claims (2)

Patent claims: 1. A process for the production of aluminum-silicon alloys by using a binder, granules or briquettes are formed from the charge, which consists of silica-alumina-based material and a mixture of petroleum coke and another type of carbon that provides the reducing carbon, and the charge is implemented in this form in an electric furnace, after which alloy and slag are separated from each other, characterized in that alcoholic sulphite waste liquor based on the cations of sodium, magnesium or ammonium is used as a binder for the granulation or briquetting of the batch, that as a second type of carbon Carbon black is used and that petroleum coke and carbon black are used in an amount in which the proportion of non-volatile carbon is 96 to 100 ° _{o of} the stoichiometric required amount and also the ratio of. nonvolatile carbon from petroleum coke and soot is in the range 3.0: 1 to 0.5: 1. 2. The method according to claim 1, characterized in that a batch is used, which in addition Chlorides and fluorides of the alkali and alkaline earth metals individually or together in one Contains an amount equal to 3% of the total weight of the batch.