Method for neutralizing sulfuric acid acidic solution and hydrometallurgical method for nickel oxide ore

Patent metadata

Field	Value
Publication number	US-9512503-B2
Application number	US-201515021364-A
Country	US
Kind code	B2
Filing date	Jan 21, 2015
Priority date	May 13, 2014
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

A hydrometallurgical method for nickel oxide ores, whereby the pH of a neutralized solution can be stabilized. The hydrometallurgical method comprises a sulfuric acid leaching step of leaching an ore slurry of a nickel oxide ore with sulfuric acid, a neutralization step of neutralizing a crude nickel sulfate aqueous solution by adding a neutralizing agent thereto, and a dezincification step of removing zinc as zinc sulfide by adding a sulfurizing agent to a neutralized solution; wherein in the neutralization step, the amount of the neutralizing agent added is adjusted using, as an index, a neutralizing agent addition ratio that indicates the amount of the neutralizing agent added relative to the amount of free sulfuric acid in the crude nickel sulfate aqueous solution.

First claim

The invention claimed is:

1. A method for neutralizing a sulfuric acid acidic solution by adding a neutralizing agent thereto,
wherein the flow rate of the sulfuric acid acidic solution is measured to determine a neutralization start solution flow rate,
the flow rate of the neutralizing agent is measured to determine a neutralizing agent addition flow rate,
the sulfuric acid acidic solution is sampled at predetermined time intervals to measure a free sulfuric acid concentration by a titration method, and the free sulfuric acid concentration is used as a free sulfuric acid coefficient,
a neutralizing agent addition ratio is determined using the neutralization start solution flow rate, the neutralizing agent addition flow rate, and the free sulfuric acid coefficient,
wherein the neutralizing agent addition ratio is represented by the following formula:
R=Qc /( Qs×C )

wherein R is the neutralizing agent addition ratio, Qc is the neutralizing agent addition flow rate, Qs is the neutralization start solution flow rate, and C is the free sulfuric acid coefficient, and
the amount of the neutralizing agent added is adjusted using, as an index, the neutralizing agent addition ratio to thereby neutralize the sulfuric acid acidic solution to a desired pH without using a pH meter.

2. The method for neutralizing a sulfuric acid acidic solution according to claim 1 , wherein the amount of the neutralizing agent added is adjusted so that the neutralizing agent addition ratio is maintained at a predetermined target value.

3. The method for neutralizing a sulfuric acid acidic solution according to claim 1 , wherein the amount of the neutralizing agent added is adjusted so that the neutralizing agent addition ratio is within a predetermined range.

4. A hydrometallurgical method for nickel oxide ores, is the method comprising:
a sulfuric acid leaching step of leaching an ore slurry of a nickel oxide ore with sulfuric acid;
a neutralization step of neutralizing a crude nickel sulfate aqueous solution obtained in the sulfuric acid leaching step by adding a neutralizing agent thereto; and
a dezincification step of removing zinc as zinc sulfide by adding a sulfurizing agent to a neutralized solution obtained in the neutralization step;
wherein in the neutralization step,
the flow rate of the crude nickel sulfate aqueous solution is measured to determine a neutralization start solution flow rate,
the flow rate of the neutralizing agent is measured to determine a neutralizing agent addition flow rate,
the crude nickel sulfate aqueous solution is sampled at predetermined time intervals to measure a free sulfuric acid concentration by a titration method, and the free sulfuric acid concentration is used as a free sulfuric acid coefficient,
a neutralizing agent addition ratio is determined using the neutralization start solution flow rate, the neutralizing agent addition flow rate, and the free sulfuric acid coefficient,
wherein the neutralizing agent addition ratio is represented by the following formula:
R=Qc /( Qs×C )

wherein R is the neutralizing agent addition ratio, Qc is the neutralizing agent addition flow rate, Qs is the neutralization start solution flow rate, and C is the free sulfuric acid coefficient, and
the amount of the neutralizing agent added is adjusted using, as an index, the neutralizing agent addition ratio to thereby neutralize the crude nickel sulfate aqueous solution to a desired pH without using a pH meter.

5. The hydrometallurgical method for nickel oxide ores according to claim 4 ,
wherein the amount of the neutralizing agent added is adjusted so that the neutralizing agent addition ratio is maintained at a predetermined target value.

6. The hydrometallurgical method for nickel oxide ores according to claim 4 , wherein the amount of the neutralizing agent added is adjusted so that the neutralizing agent addition ratio is within a predetermined range.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Nakamura Shinichiro
• Nakano Osamu

Classifications

• Y02P10/20

  Recycling · CPC title

• Y02P10/234

  Cross-Sectional Technologies · mapped topic

• C22B23/00

  Obtaining nickel or cobalt · CPC title

• C02F1/66

  by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58) · CPC title

• C22B23/0461 Primary

  by chemical methods · CPC title