JPH06227814A - Method for producing high-purity zinc oxide powder - Google Patents

Abstract

(57) [Summary] [Purpose] In a method for producing zinc white from zinc dross, it is intended to prevent solid impurities in raw materials from being mixed in the product. [Constitution] A raw material zinc dross is put into a crucible, the surface thereof is covered with borax, and a raw material is evaporated and burned in a state where a molten layer is formed on the surface to produce zinc white. [Effect] Since the solid impurities in the raw material are dissolved by the borax, the mixing of the solid impurities into the product is reduced, and the quality of the product is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing zinc oxide powder of high purity from galvanized dross and other zinc dross.

[0002]

2. Description of the Related Art Zinc oxide powder (zinc white) is used as various industrial products, for example, as a vulcanization accelerator for rubber, as an additive for paints such as enamel, and as a raw material for materials for electronic parts such as ferrite. There is. The zinc oxide powder is produced by a method in which zinc vapor generated by melting metallic zinc is burned by supplying air in a combustion chamber and then rapidly cooled, as also disclosed in Japanese Patent Publication No. 60-5529. Has been done.
Further, in Japanese Patent Laid-Open No. 63-259035, a byproduct zinc-containing material such as a plating dross produced as a by-product in an iron mill has a temperature of 900.
It is a method for producing a zinc oxide powder, which is heated in a reducing atmosphere volatilization furnace at ˜1100 ° C. to make a jetted zinc-containing gas in an oxidized or reduced state and is recovered while being cooled. However, although a high-purity zinc oxide powder can be produced as such from a high-grade zinc metal raw material such as electric zinc, when a low-grade by-product zinc-containing material such as plated dross is used as a raw material, There is a problem that impure solids such as aluminum oxide and iron oxide contained in the raw material are scattered and mixed in the zinc oxide powder product, which deteriorates the quality of the product.

The present invention is intended to solve such a problem, and provides a method for producing high-purity zinc oxide powder containing few impurities from zinc-plated dross containing many impurities and other zinc dross raw materials. It is a thing. The gist is a method for producing high-purity zinc oxide powder in which borax is put on the surface of zinc dross melted in a melting furnace, the generated zinc vapor is oxidatively burned, and the cooled zinc oxide powder is recovered. .

The present invention will be described below with reference to the drawings. The figure shows an example of a manufacturing pattern presented for explaining the present invention. 1 is a melting furnace. Reference numeral 2 denotes a zinc dross raw material containing impurities such as metallic zinc, aluminum oxide and iron oxide, and other zinc dross raw materials, which are melted and housed in the melting furnace 1. A heating medium 3 such as a gas or an electric heating body melts the zinc dross raw material 2 in the melting furnace 1 and is provided on the furnace wall of the melting furnace 1. Reference numeral 4 is a lid of the melting furnace 1. Reference numeral 5 denotes a zinc vapor jet, which is provided on the lid 4. A combustion chamber (furnace) 6 is placed on the lid 4, and a combustion air suction hole 7 is provided at an arbitrary position.

That is, the surface layer portion of solid impurities such as aluminum oxide and iron oxide floating in a high-boiling point (907 ° C.) zinc dross bath melted in the melting furnace 1 has a low boiling point (741 ° C.). It reacts with sand and dissolves to form a molten layer 8 of borate in which solid impurities and borax are integrated on the surface of the dissolution bath. As a result, when the bubbles 9 of the zinc vapor rising in the zinc dross bath that is melted and boils in the melting furnace 1 are released from the bath surface, without scattering solid impurities,
In addition, the solid impurities that rise together with the solid impurities are also captured and reduced when passing through the molten layer 8. The high-temperature zinc oxide thus oxidized in the combustion chamber 6 is extracted from the discharge port 10 and cooled while being guided to the recovery container (not shown),
High-quality zinc oxide powder with extremely few impurities is recovered. Next, examples of the present invention will be described.

[0006]

EXAMPLE Zinc oxide powder was manufactured by charging zinc dross as a raw material into a melting furnace of an apparatus as shown in FIG. 1 and further adding borax on it. The raw material zinc dross amount is 1300 kg, and the added borax is 120 g. Induction heating device output 2
It is 0 kW. Table 1 shows the analysis results of impurities in the produced zinc oxide powder. The analysis of impurities was performed by a method in which zinc oxide powder was dissolved in acetic acid and insoluble matters were used as impurities. As shown in Table 1, the zinc oxide powder produced by the method of the present invention has a significantly lower amount of impurities than the conventional method and is of good quality.

[0007]

[Table 1]

[0008]

As described above, according to the present invention, the solid impurities in the raw material are dissolved by the borax even if the low-grade by-product zinc-containing material such as plated dross is used as the raw material. Mixing of solid impurities was reduced, and it became possible to manufacture high-purity zinc oxide powder.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus presented for explaining the method of the present invention.

[Explanation of symbols]

 1 Melting Furnace 2 Zinc Dross Raw Material 3 Heat Medium 4 Melting Furnace Lid 5 Zinc Vapor Jet 6 Combustion Chamber 7 Combustion Air Suction Hole 8 Borate Molten Layer 9 Zinc Vapor Bubble 10 Discharge Port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuko Tonooka 1-1 Tobahata-cho, Tobata-ku, Kitakyushu, Fukuoka Prefecture Inside the Yawata Works, Nippon Steel Corporation (72) Inventor Tadao Kitazawa Hachiman-higashi, Kitakyushu, Kitakyushu 1-3-1 Otani-ku, Astec Co., Ltd. Irie

Claims (1)

[Claims] 1. A borax is put on the bath surface of zinc dross melted in a melting furnace to oxidize and burn the generated zinc vapor,
A method for producing high-purity zinc oxide powder, which comprises recovering cooled zinc oxide powder.