Process for producing hematite for ironmaking

Patent metadata

Field	Value
Publication number	US-9914648-B2
Application number	US-201414900806-A
Country	US
Kind code	B2
Filing date	Jun 3, 2014
Priority date	Jul 3, 2013
Publication date	Mar 13, 2018
Grant date	Mar 13, 2018

Abstract

A process is provided for obtaining a hematite-containing material that can be used for ironmaking. The process includes separating a leach residue from a hydrometallurgical refining plant into an overflow and an underflow using a wet cyclone under a condition that the wet cyclone is adjusted to have a setting between 1 μm or less and 2 μm or less as a classification particle size for the overflow. The process then includes separating the overflow into a strong magnetic substance and a weak magnetic substance using a strong-magnetic-field magnetic separator under a condition that magnetic field intensity is 5 to 20 [kGauss]. The process then includes using a superheated steam drying system for adjusting a moisture content of the strong magnetic substance after the separation, to be 10 wt % to 17 wt %.

First claim

The invention claimed is:

1. A process for producing hematite for ironmaking that utilizes a leach residue as a raw material, the leach residue being obtained from a hydrometallurgical refining plant where a nickel oxide ore is treated by a high pressure acid leach process, the process for producing hematite comprising at least the following three steps in sequence:
a separation step of separating the leach residue into an overflow and an underflow by a wet cyclone so that particles of a selected size or smaller than the selected size are separated into the overflow, and particles greater than the selected size separated into the underflow, the selected size being selected from a range of 1-2 μm;
a physical separation step of separating the overflow into a strong magnetic substance and a weak magnetic substance with magnetic force using a strong-magnetic-field magnetic separator under a condition such that magnetic field intensity is 5 to 20 kGauss; and
a dehydration step of using a superheated steam drying system for adjusting the moisture content of the strong magnetic substance of the overflow after the physical separation step, to be 10% to 17% by weight, thereby producing a hematite cake.

2. The process for producing hematite for ironmaking according to claim 1 , wherein the moisture content of the strong magnetic substance of the overflow after the physical separation step is 35% to 45% by weight, and
a pressure of superheated steam in the superheated steam drying system is 0.5 MPa to 0.7 MPa and a temperature of the superheated steam is 150° C. to 180° C.

3. The process for producing hematite for ironmaking according to claim 2 , wherein the wet cyclone is adjusted in the separation step to have a setting of 1 μm or less as a classification particle size for the overflow.

4. The process for producing hematite for ironmaking according to claim 1 , wherein the wet cyclone is adjusted in the separation step to have a setting of 1 μm or less as a classification particle size for the overflow.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Ohara Go
• KAN Yasumasa
• Imamura Masaki

Classifications

• Y02P10/212

  Cross-Sectional Technologies · mapped topic

• C22B23/0407

  Leaching processes · CPC title

• C01G49/06 Primary

  Ferric oxide [Fe2O3] · CPC title

• B03C2201/22

  characterised by the magnetic field, e.g. its shape or generation · CPC title

• B03C1/30

  Combinations with other devices, not otherwise provided for · CPC title