METHOD FOR NEUTRALIZING SULFURIC ACID ACIDIC SOLUTION AND HYDROMETALLURGICAL METHOD FOR NICKEL OXIDE ORE

摘要

Provided is a method for neutralizing a sulfuric acid acidic solution, whereby the pH of a neutralized solution can be stabilized, and also provided is a hydrometallurgical method for nickel oxide ores.;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. This method is not affected by changes in the liquid temperature or by neutralized precipitates adhering to a pH meter, can prevent insufficient addition and excessive addition of the neutralizing agent, and can stabilize the pH of the neutralized solution. The removal efficiency of zinc can be maintained in the dezincification step, and the efficiency of solid-liquid separation can be maintained.

主权项

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.