JP2000290650A - Method for decomposing aluminum nitride in aluminum dross by adding aluminum dross and aqueous sodium hydroxide solution - Google Patents

Abstract

(57) [Problem] To provide aluminum dross during the production and recycling of aluminum, aluminum nitride is contained. If this nitrogen is not removed, it will react with water to produce ammonia, resulting in harmful industrial waste. Therefore, it is required to remove nitrogen at low cost. SOLUTION: Calcium hydroxide or calcium oxide is mixed with aluminum dross. By adding an aqueous solution of sodium hydroxide to this mixture, the aluminum nitride in the aluminum dross is hydrolyzed and removed as ammonia gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inexpensively removing aluminum nitride from aluminum dross generated during the production and recycling of aluminum, and effectively utilizing the same.

[0002]

2. Description of the Related Art Conventionally, there are two methods for decomposing aluminum nitride in aluminum dross: (1) a water immersion method and (2) a melting method.
In addition, there is a disadvantage that the solidification property is weakened. (2)
Is expensive and industrial use is not economically competitive. As a reference on such a situation, there is “Survey and Research Report on the Treatment and Recycling of Aluminum Dross” (March 1997, Japan Light Metal Association).

[0003]

The present invention relates to the above (1),
It is an object of the present invention to solve the problem (2) and to process aluminum dross in a short time and to make it a reusable resource at a low cost.

[0004]

Means for Solving the Problems As a specific method,
An aqueous solution of sodium hydroxide is added to aluminum dross for reaction. The reaction occurs rapidly and the nitrogen in the aluminum nitride in the dross is removed as ammonia gas.
The dross thus treated can be used as a soil improvement material for excavated mud in civil engineering works and the like.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In order to treat a large amount of dross as industrial waste, a dedicated facility is made.

[0006]

EXAMPLE 800 ml of an aqueous solution of 3,5 mol / l sodium hydroxide is added to 1 kg of dross. The reaction is completed in about 3 minutes, depending on the ratio of the constituent components of the dross, and nitrogen of AlN is removed as ammonia gas. Ammonia is not generated even when water is added to the treated material, and when 5% of the treated material is added to mud from which water can be isolated, it solidifies in about 2 days.

[0007]

According to this method, it is expected that aluminum dross, which has been regarded as industrial waste, is reused by relatively inexpensive chemical treatment. This is an epoch-making thing that not only makes the aluminum dross disposal site unnecessary, but also can be used for soil improvement.

Claims (1)

[Claims] 1. A method for removing nitrogen contained in aluminum dross, comprising adding an aqueous solution of sodium hydroxide to aluminum dross to hydrolyze aluminum nitride and rapidly removing the aluminum nitride.