CS205408B1 - Manufacturing process of aluminium-titanium master alloy - Google Patents

Description

(54)

Method of production of aluminum-titanium master alloy

The invention relates to a method for producing an aluminum-titanium master alloy in a reducing aluminum electrolyser.

Industrially, the aluminum-titanium master alloy is mainly produced by dissolving sponge metal in molten aluminum. The disadvantage of this method is the high cost of the titanium sponge and the considerable energy consumption to turn the aluminum and titanium into a liquid state and the need for further remelting at the point of consumption and loss of burn-through to aluminum at each remelting.

The disadvantages of the present invention are to eliminate the process for the production of an aluminum-titanium alloy according to the invention, which consists in the fact that during the production of aluminum on a Mall-Heroult electrolyser, regular slag is fed to the electrolyte. fractions below 40 µm and containing predominantly alumina and titanium dioxide and partially dextrous, magnesium, ferric and silicon oxides, where it is reduced, while the calcium and magnesium fluoride concentrations are kept together in the electrolyte together up to 9% by weight and the aluminate titanium is retained Titanium content up to 1% by weight.

The slag used in the ferrotitanium production is a material with a high content of alumina and titanium dioxide, which can be electrochemically reduced after dissolution in the cryolite melt. Calcium and magnesium, as more electronegative elements, will not be eliminated from the electrolyte, but will affect its physicochemical properties, for example, the solubility of alumina and their total concentration should not exceed 9% by weight. Iron oxide and silica due to their low slag contents and the reason why the aluminum-titanium master alloy is mostly used for alloying

20S 408 of such aluminum alloys, in which it is often necessary to additionally add some of these components, is not a defect. Also important is the correct slag grain size, which must be finely ground so that the particles do not exceed 100 µm. The phase diagram of the aluminum-titanium system shows that titanium forms an intermetallic compound TiAlg with aluminum. In order to completely eliminate the risk of this compound falling out of the liquid metal to the cathode bottom of the electrolyzer, the maximum titanium concentration in aluminum should not exceed 1%,

The proposed technology reduces aluminum losses by burn-through, reduces handling requirements, because at the production site of the electrolytic aluminum, the pre-alloy in liquid form is produced and consumed at the same time. Titanium and aluminum contained in the slag are effectively utilized, it positively influences the physicochemical properties of the electrolyte, and is advantageous from the energy and environmental point of view.

The slag dosing can be leveled together with alumina or separately, it is not necessary to maintain an exact ratio of aluminum oxide. Even with separate slag dosing, the situation is more favorable from a technological point of view, or more easily, the electrolyte is supersaturated and thus cathodic deposits are formed.

The produced aluminum-titanium master alloys are used for grain refinement of aluminum alloys intended for forming and to a lesser extent also for ingot molding and sand casting.

By way of example, an operating experiment on an industrial 75 kA self-baking anode electrolyzer, which does not limit the scope of the invention, serves to illustrate the production method of the invention.

Priklad prevedenia

100 kg of slag from ferrotitanium production, containing 60% by weight of alumina, 25% by weight of titanium dioxide, 8% by weight of calcium oxide, 3% by weight of magnesium oxide, 3% by weight, were initially metered into industrial 75 kA electrolysis for electrolytic aluminum welding. iron oxide, 3 wt.% silica and 1 wt.% impurities, finely milled to contain no more than 100 µm particles, and additionally 50 x 50 kg slag 3 times a week during production. The experiment ran for 2 and a half months, with the titanium concentration in the product ranging from 0.4 to 0.6% by weight and the calcium fluoride content together with the magnesium fluoride in the electrolyte did not exceed 5% by weight.

This alloy was used to alloy the Al-lg-Si 05 alloy containing 0.05 to 0.2% by weight of titanium.

In electrolysers, where the method of technology management, the quality of the raw materials used and their construction allows to work with higher contents of calcium and magnesium fluoride, it is possible to achieve with a slag of this composition up to 1% titanium content in the excreted aluminum.

Claims (1)

Such aluminum alloys, in which one of these components is often required to be removed, are not a problem, so is the proper grain size, which must be finely ground so that the particles do not exceed 100 µm. It follows from the phase diagram of the aluminum-titanium system that titanium forms an intermetallic TiAlg compound with aluminum. In order to completely eliminate the risk of the liquid metal coming out of the liquid metal to the bottom of the electrolyzer cathode, the maximum titanium concentration in aluminum should not exceed 1%. The proposed technology reduces aluminum loss through burns, reduces handling requirements, because at the point of production of electrolytic aluminum there is also produced and consumed master alloy in liquid form. Titanium and aluminum are utilized efficiently in the slag, positively influencing the physico-chemical properties of the electrolyte, it is advantageous from the energetic and ecological point of view. The dosing of the slag can be aligned with the alumina or separately, that is, it is not necessary to keep the exact ratio of alumina. Even with the separation of the slag dosing, the technological situation is more favorable, or the harder one to reach the supersaturation of the electrolyte and thus the formation of cathode sediments. The aluminum-titanium alloys produced are used to refine the aluminum alloy grains for molding and, to a lesser extent, to mold and sand castings. As an example, an industrial 75 kA self-inducing anode industrial electrolyser, which does not limit the scope of the invention, serves as an example to illuminate the process of the invention. EXAMPLE OF EMBODIMENT Into an industrial 75 kA electrolytic cell for aluminum electrolytic, 100 kg of ferrotitanium slag containing 60% by weight of aluminum oxide, 25% by weight of titanium dioxide, 8% by weight of calcium oxide, 3% by weight of magnesium oxide, 3% The weight of iron oxide, 3% by weight of silica and 1% by weight of impurities, finely divided to not contain more than 100 µm and more during production 3 times per week for 50 kg of slag. The experiment ran for 2 and a half months, with the titanium concentration in the product ranging from 0.4 to 0.6% by weight, and the calcium fluoride content with the fluoride in the electrolyte did not exceed 5% by weight. This alloy was used to alloy Al-Li-Si-05 alloy containing 0.05 to 0.2% by weight of titanium. Up to 1% of the titanium content of the precipitated aluminum can be achieved with the slag of the composition on the electrolysers where the technology of the process, the quality of the raw materials used and the construc- tion allows it to work with higher levels of calcium and magnesium fluoride. BRIEF DESCRIPTION OF THE INVENTION The process for the production of alumina titanium alloy has been characterized in that the alumina in the Uall-Heroult electrolytic cell is regularly fed with alumina to produce a ground slag resulting from the aluminothermic production of ferrotitanium, grains up to 100 µm with a fraction fraction below 40 µm and containing predominantly aluminum alumina and titanium oxide and partly calcium, magnesium, ferric and silicon oxides, whereby the concentration of calcium and magnesium fluoride is maintained in the electrolyte up to 9% by weight and the resulting aluminum-titanium alloy is maintained in the content % titanium to 1% by weight.