Method for producing hematite for ironmaking

Patent metadata

Field	Value
Publication number	US-9828256-B2
Application number	US-201314777561-A
Country	US
Kind code	B2
Filing date	Dec 12, 2013
Priority date	Mar 26, 2013
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

Provided is a method for producing hematite for ironmaking, capable of using a conventional Ca-based neutralizing agent and a base rock-derived neutralizing agent other than the Ca-based neutralizing agent. The method is performed by a process of adding a mineral acid and an oxidizing agent to an ore containing iron and a valuable metal and then leaching the valuable metal under high temperature and pressure, and includes (1) a high-pressure acid leaching step, (2) a preliminary neutralization step, (3) a first solid-liquid separation step, (4) a neutralization step, (5) a second neutralization step, (6) a third solid-liquid separation step, (7) a step of adding part of the Fe-enriched slurry as a seed crystal in the neutralization step (4), and (8) a second solid-liquid separation step.

First claim

The invention claimed is:

1. A method of producing hematite for ironmaking, the method comprising:
a high-pressure acid leaching step of mixing an ore slurry with a mineral acid and leaching under a high temperature and pressure to form a leach slurry;
a preliminary neutralization step of adding a base rock or magnesium hydroxide to the leach slurry;
a first separation step of separating the leach slurry after preliminary neutralization into a Ni-enriched slurry and an Fe-enriched slurry;
a first neutralization step of neutralizing the Ni-enriched slurry with limestone or slaked lime, the first neutralization step including adding to the Ni-enriched slurry an amount of the Fe-enriched slurry as a seed crystal;
a second separation step of solid liquid separating a precipitate that is obtained from the first neutralization step of neutralizing the Ni-enriched slurry;
a second neutralization step of neutralizing the Fe-enriched slurry obtained in the first separation step with sodium hydroxide or potassium hydroxide; and
a third separation step of separating the Fe-enriched slurry that is neutralized in the second neutralization step into hematite and a liquid component.

2. The method of producing hematite for ironmaking according to claim 1 , wherein the amount of the Fe-enriched slurry added as the seed crystal in the first neutralization step is 50% by weight to 80% by weight with respect to the precipitate that is generated due to the neutralization in terms of a weight ratio.

3. The method of producing hematite for ironmaking according to claim 1 , further comprising:
adjusting a moisture content of the hematite obtained in the third separation step to provide a hematite with a moisture content of 10% by weight to 17% by weight, the step of adjusting the moisture content being carried out subsequent to the third separation step.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Ohara Go
• Sasaki Hideki
• KAN Yasumasa
• Imamura Masaki

Classifications

• C22B3/44

  by chemical processes (treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42) · CPC title

• Y02P10/234

  Cross-Sectional Technologies · mapped topic

• C22B23/00

  Obtaining nickel or cobalt · CPC title

• C01G49/06 Primary

  Ferric oxide [Fe2O3] · CPC title

• C22B3/06

  in inorganic acid solutions {, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions} · CPC title