Metal oxide smelting method

Patent metadata

Field	Value
Publication number	US-2020010925-A1
Application number	US-201816484654-A
Country	US
Kind code	A1
Filing date	Jan 31, 2018
Priority date	Feb 9, 2017
Publication date	Jan 9, 2020
Grant date	—

Abstract

Provided is a smelting method in which, for example, a metal oxide such as a nickel oxide ore including nickel oxide is used as a source material and is reduced with a carbonaceous reducing agent to obtain a reduced product, with which method efficient processing can be achieved. This metal oxide smelting method is, for example, a nickel oxide ore smelting method. Specifically, the method includes a reduction process step that has: a drying step in which a mixture that was obtained by mixing a metal oxide and a carbonaceous reducing agent is dried; a preheating step in which the dried mixture is preheated; a reduction step in which the preheated mixture is reduced using a rotary hearth furnace, said rotary hearth having a hearth that rotates and not having a partition structure in an interior; and a cooling step in which the obtained reduced product is cooled.

First claim

1 . A metal oxide smelting method comprising a reduction treatment step including:
a drying step in which a mixture obtained by mixing a metal oxide and a carbonaceous reducing agent is dried; a preheating step in which the dried mixture is preheated; a reduction step in which the preheated mixture is reduced using a rotary hearth furnace, the rotary hearth having a hearth that rotates and not having a partition structure in an interior; and a cooling step in which the obtained reduced product is cooled.

2 . The metal oxide smelting method according to claim 1 , wherein the reduced product obtained through the reduction step is subjected to a temperature maintenance step in which the reduced product is maintained at a prescribed temperature in the rotary hearth furnace, and after maintained for a prescribed time, the reduced product is supplied to the cooling step.

3 . The metal oxide smelting method according to claim 2 , wherein a treatment in the reduction step and a treatment in the temperature maintenance step are performed using the same rotary hearth furnace.

4 . The metal oxide smelting method according to claims 2 , wherein the reduced product is maintained at a temperature of 1300° C. or higher and 1500° C. or lower in the temperature maintenance step.

5 . The metal oxide smelting method according to claim 1 , wherein in the reduction step, reduction is performed while a reducing temperature is set to 1200° C. or higher and 1500° C. or lower.

6 . The metal oxide smelting method according to claim 5 , wherein in the reduction step, the mixture is reduced at reducing temperatures of two steps,
the reducing temperature at the first step is 1200° C. or higher and 1450° C. or lower, and the reducing temperature at the second step is 1300° C. or higher and 1500° C. or lower.

7 . The metal oxide smelting method according to claim 6 , wherein the rotary hearth furnace includes a plurality of heating sources, and a temperature distribution inside the rotary hearth furnace is controlled by controlling an amount of energy supplied to each heating source.

8 . The metal oxide smelting method according to claim 1 , wherein the mixture to be dried in the drying step is obtained through
a mixing treatment step in which at least a metal oxide and a carbonaceous reducing agent are mixed to obtain a mixture, and a pretreatment step in which a treatment of forming the obtained mixture into a lump product or a treatment of filling the mixture in a prescribed container is performed.

9 . The metal oxide smelting method according to claim 1 , further comprising a separating step in which the reduced product cooled in the cooling step in the reduction treatment step is separated into a metal and slag and the metal is recovered.

10 . The metal oxide smelting method according to claim 1 , wherein the metal oxide is nickel oxide ore.

11 . The metal oxide smelting method according to claim 1 , wherein the reduced product contains ferronickel.

12 . The metal oxide smelting method according to claim 2 , wherein in the reduction step, reduction is performed while a reducing temperature is set to 1200° C. or higher and 1500° C. or lower.

13 . The metal oxide smelting method according to claim 3 , wherein in the reduction step, reduction is performed while a reducing temperature is set to 1200° C. or higher and 1500° C. or lower.

14 . The metal oxide smelting method according to claim 4 , wherein in the reduction step, reduction is performed while a reducing temperature is set to 1200° C. or higher and 1500° C. or lower.

15 . The metal oxide smelting method according to claim 12 , wherein in the reduction step, the mixture is reduced at reducing temperatures of two steps,
the reducing temperature at the first step is 1200° C. or higher and 1450° C. or lower, and the reducing temperature at the second step is 1300° C. or higher and 1500° C. or lower.

16 . The metal oxide smelting method according to claim 15 , wherein the rotary hearth furnace includes a plurality of heating sources, and a temperature distribution inside the rotary hearth furnace is controlled by controlling an amount of energy supplied to each heating source.

17 . The metal oxide smelting method according to claim 2 , wherein the mixture to be dried in the drying step is obtained through
a mixing treatment step in which at least a metal oxide and a carbonaceous reducing agent are mixed to obtain a mixture, and a pretreatment step in which a treatment of forming the obtained mixture into a lump product or a treatment of filling the mixture in a prescribed container is performed.

18 . The metal oxide smelting method according to claim 2 , further comprising a separating step in which the reduced product cooled in the cooling step in the reduction treatment step is separated into a metal and slag and the metal is recovered.

19 . The metal oxide smelting method according to claim 2 , wherein the metal oxide is nickel oxide ore.

20 . The metal oxide smelting method according to claim 2 , wherein the reduced product contains ferronickel.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Iseki Takashi
• Goda Yukihiro
• Kobayashi Jun-Ichi
• Okada Shuji

Classifications

• C22B23/021

  by reduction in solid state, e.g. by segregation processes · CPC title

• C22B1/216

  in rotary furnaces · CPC title

• C22B23/023 Primary

  with formation of ferro-nickel or ferro-cobalt · CPC title

• C22B1/242

  with binders · CPC title

• C22B5/10 Primary

  by solid carbonaceous reducing agents · CPC title