Method for preparing aluminum-lanthanum master alloy by aluminothermic reduction method

Abstract

The invention discloses a method for preparing an aluminum-lanthanum intermediate alloy by using an aluminothermic reduction method. The method comprises the following steps that 1, lanthanum oxide, sodium chloride, potassium chloride and cryolite are uniformly mixed to prepare a salt-mixture; 2, pure aluminum is put into a crucible of a medium-frequency induction furnace for melting after dirt onthe surface of the pure aluminum is removed, and then the salt-mixture is added according to the proportion until the salt-mixture is molten; 3, heat preservation is carried out on the obtained mixture for 20-40 minutes at the temperature of 750-850 DEG C, the mixture is uniformly stirred, and then aluminothermic reduction reaction is carried out on the mixture; and 4, the mixture is cooled to 730-780 DEG C, waste residue on the surface of the mixture is removed, the mixture is poured into a metal mould, air cooling is carried out, and then an aluminum-lanthanum intermediate alloy ingot is prepared. The method adopts a chloride-fluoride mixed fused salt sysyem, wherein the oxide is taken as the raw material, the aluminum-lanthanum alloy is prepared through the fused salt metallothermic reduction method, and therefore the production process can be shortened, the energy consumption can be reduced, and the production cost can be reduced.

Description

technical field [0001] The invention relates to an alloy preparation technology, in particular to a method for preparing an aluminum-lanthanum master alloy by an aluminothermic reduction method. Background technique [0002] At present, the industrial production of aluminum-lanthanum master alloys mainly adopts the fusion method to prepare master alloys with low rare earth content. Rare earth metals are directly added to aluminum alloys to prepare master alloys, but rare earths are prone to peritectic reactions in molten aluminum, resulting in inclusions, making rare earth The burning loss is large, and the alloy composition is very uneven. Due to the high melting point of rare earth, the preparation process is complicated and the production cost is high. [0003] The use of molten salt electrolysis to prepare mixed rare earth aluminum alloys has the advantages of continuous operation, simple equipment, and low cost, but the molten salt electrolysis method has low current e...

AI Technical Summary

Problems solved by technology

[0002] At present, the industrial production of aluminum-lanthanum master alloys mainly adopts the fusion method to prepare master alloys with low rare earth content. Rare earth metals are directly added to aluminum alloys to prepare master alloys, but rare earths are prone to peritectic reactions in molten aluminum, resulting in inclusions, making rare earth Large burning loss, very uneven alloy composition

Due to the high melting point of rare earth, the preparation process is complicated and the production cost is high

[0003] The use of molten salt electrolysis to prepare mixed rare earth aluminum alloys has the advantages of continuous operation, simple equipment, and low cost, but the current efficiency of molten salt electrolysis is low, high energy consumption, and large pollution. La 2 o 3 - Fluoride system, which has higher requirements on raw materials; common Fe 3+ 、RE 3+ Other metal ions may also be reduced and precipitated on the cathode during the electrolysis process, the content of rare earths is difficult to control, and the composition fluctuates greatly, which affects the purity of the alloy; and the production of this method is likely to lead to changes in the process conditions of the aluminum electrolytic cell, and the common SO 4 2- , NO 3- , Cl - etc. may participate in the anode reaction, resulting in low efficiency of the electrolytic cell. At the same time, toxic gases will be produced during the electrolysis process, which will seriously pollute the environment and damage the health of operators.

[0004] Metal thermal reduction process is complex and costly