SU1774964A3 - Method of obtaining alloying element for modifying aluminium alloys - Google Patents

Description

The invention relates to the metallurgy of non-ferrous metals, in particular to methods for producing alloys based on aluminum used for modifying wrought and cast aluminum alloys, one of the components of which may be silicon, magnesium or copper.

The closest to the claimed technical essence is a method of obtaining a master alloy for modifying aluminum alloys, including melting aluminum, introducing a component (Mg, SI or Cu) forming an alloy of eutectic composition with aluminum, loading potassium fluoroborate at 600-650 ° C, introducing spongy titanium under the layer of the formed flux at 800-950 ° C.

The disadvantage of this method is the loss of potassium fluoroborate, which is 20-30%.

The aim of the invention is to increase the degree of extraction of boron and titanium in the alloy, to reduce the loss of raw materials and emissions of harmful substances into the environment.

This goal is achieved by the fact that in the proposed method for producing a master alloy for modifying aluminum alloys, including melting aluminum, introducing a component that forms an alloy of eutectic composition with aluminum, loading potassium fluoroborate and spongy titanium, introducing potassium fluoroborate is carried out in a mixture with potassium chloride at a ratio of potassium fluoroborate to potassium chloride (4.3-4.9): 1 by weight.

The rationale for this method is as follows: as you know, the fusibility diagram of the KCI-KBF4 system belongs to the eutectic type with the eutectic point of the diagram corresponding to 483 ° C. with 18% KCI and 82% KBF. 1. which corresponds to the ratio KBF4: KCI = 4.6: 1.

The introduction of potassium fluoroborate in a mixture with potassium chloride makes it possible to reduce the melting point from 54 ° C for potassium fluoroborate

Joint venture

1774964 AZ to 483 ° C for the eutectic mixture and reduce the decomposition of KBFn.

Formed by the reaction AI + KBF4 = B + KF + AIF ₃ potassium cryolite in a mixture with potassium chloride acts as a covering flux. When the first portion of a mixture of fluoroborate and potassium chloride is introduced, due to the interaction of aluminum with potassium fluoroborate, a solid crust of a mixture of fluorides with potassium chloride is formed on the aluminum surface by reaction, which prevents gaseous boron fluorides from leaving the interaction zone. The introduction of subsequent portions of the mixture under the crust of the solid electrolyte layer formed on the surface leads to the accumulation of the coating flux and its melting. The introduction of titanium is carried out under a layer of liquid coating flux at 800-950 ° C.

Thus, the use of the KCI-KBF4 eutectic mixture and its portioned introduction, in comparison with the prototype, makes it possible to increase the degree of boron assimilation by reducing the decomposition of potassium fluoroborate.

An increase in the degree of boron assimilation helps to reduce harmful emissions into the atmosphere.

The use of mixtures of potassium fluoroborate with potassium chloride outside the limits. ratio (4.3-4.9): 1, the set goal is not achieved, since the melting point of the mixture rises and the decomposition of potassium fluoroborate increases.

Example 1. In a graphite crucible, 280 g of technical grade aluminum of grade A6 (GOST 1 1069-74) was melted, and at 680-700 ° C, cathode copper MOOK (GOST 859-78) with a mass of 170 g, preheated to 300 ° C, was introduced. To reduce the melt temperature to the required one (600-620 ° C), solid aluminum with a mass of 70 g was added. After dissolution of copper with stirring, 62 g of a mixture of fluoroborate and potassium chloride in a ratio of 4.3: 1 were introduced in ten portions of 6 g each for 20-30 minutes. Then the temperature of the melt was increased to 850 ° C, and a sponge titanium of the TG 110 grade (GOST 17746-79) weighing 30 g was loaded under the layer of the formed flux. The melt was kept under stirring for 30-35 min and was poured. In the master alloy, the content of boron, titanium, copper was determined, and the degree of assimilation of boron and titanium was calculated.

PRI me R 2. In a graphite crucible, 450 g of aluminum was melted at 700-720 ° C, preheated to

100-200 ° С silicon grade Kr1 (GOST 216969) weighing 60 g. After dissolving silicon with stirring, a mixture of fluoroborate and potassium chloride weighing 62 g was introduced in portions of ~ 6 g each. Further, the process was carried out as described in example 1.

Example 3. In a graphite crucible, 450 g of aluminum was melted at 670-690 ° C, and 3Or of magnesium grade Mg (GOST 804-74) was loaded. With the dissolution of magnesium at a melt temperature not higher than 650 ° C, which was obtained by introducing 50 g of solid aluminum in portions of 6 g each, a mixture of fluoroborate and potassium chloride weighing 62 g was fed. Further, the process was carried out as described in example 1.

The rest of the experiments were carried out by varying the ratio of fluoroborate to potassium chloride 4.6: 1.4.9: 1.4.0: 1. The results of the experiments are shown in the table.

For comparison, the ligature was obtained using the same equipment according to the prototype method.

In a graphite crucible, 280 g of aluminum of technical purity grade A6 (GOST G1069-74) was melted, and at 680 ° C, cathode copper of the MOOk grade (GOST 859-78) with a mass of 170 g, preheated to 300 ° C, was introduced. Then solid aluminum with a mass of 70 g was added. After dissolving copper and lowering the temperature, 50 g of chemically pure potassium fluoroborate (GOST 9532-75) was introduced. After stirring for 25 min, the temperature of the melt was increased to 800 ° C, and a spongy titanium grade TG 110 (GOST 17746-79) weighing 430 g was introduced under the layer of the formed fluid. The melt was stirred for 30 minutes and poured.

As can be seen from the data in the table, the use of the proposed method, in comparison with the prototype, increases the degree of assimilation of boron and titanium into the ligature, which reduces the loss of raw materials and emissions of harmful substances into the environment.

The resulting master alloy can be used for the modification of alloys based on aluminum.

The proposed method was tested at the Novokuznetsk aluminum plant.

Claims (3)

Claim A method for producing a master alloy for modifying aluminum alloys, including melting aluminum, introducing a component that forms an alloy of eutectic composition with aluminum, loading potassium fluoroborate and spongy titanium, characterized in that, in order to increase the degree of extraction of boron and titanium into the master alloy. reduction of losses of raw materials and 1774964 emissions of harmful substances into the environment are carried out in a mixture with potassium chloride in their medium, the loading of fluoroboron hectares of potassium is carried out in a ratio of (4.3-4.9): 1 by weight. n * np Way Ratio Content components, ma.t Degree assimilation, t Copper Silicon | Magnesium I Bor | Titanium bora J titanium 1 Declared 4.3: 1 30.70 - • 0.66 *, 68 82.5 86.7 2 4.3: 1 10.20 - ' 0.56 *, 01 75.6 78.6 3 4.3: 1 5.61 0.59 *, 26 76.6 80, * and 4.6: 1 32.82 - - 0.70 *, 71 88.6 87.2 5 *, 6: 1 - 9.85 - 0.58 *,12 78, * 80.8 6 *, 6: 1 - - 5.76 0.62 * .37 80.5 82, * 7 *, 9: 1 30.51 - - 0.68 *, 71 8b '> 87.2 eight nine .and- *, 9: 1 * "9: 1 - 9.91 5.70 0.56 0.61 3.97 *, zo 75.6 78.2 92.3 81.1 10 _W 11 * *, 0: 1 30.62 - - 0.61 *, 28 78.2 '76, * eleven 5.2: 1 32.00 - - 0.62 * .36 79.5 80,7 12 Prototype - 30.6 - · - 0.63 *, 59 80 85 13 - - 9.6 - 0.52 3.81 70 75 fourteen 5.8 0.58 *, 2 * 75 80 Compiled by T. Demikina Editor S. Kulakova Techred M. Morgental Proofreader N. Gunko Order 3944 Circulation Subscription VNIIPI of the State Committee for Inventions and Discoveries under the USSR State Committee for Science and Technology 113035. Moscow. F-35. Raushskaya nab., 4/5 Production and Publishing Plant Patent, Uzhgorod, Gagarina st., 101