Production method for hematite for iron production

Patent metadata

Field	Value
Publication number	US-10457565-B2
Application number	US-201715724624-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Sep 18, 2014
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

Provided is a production method for refining iron oxide (hematite), which has such a low sulfur content as to be used as a raw material for ironmaking from a leach residue containing iron oxide, the leach residue being produced by a high pressure acid leach (HPAL) process and being a raw material that can be cheaply and stably procured. In the method of producing (high purity) hematite for ironmaking by a process of adding an oxidant and sulfuric acid to nickel oxide ore and then leaching nickel, a leach residue obtained after the leaching of nickel is heated to 600° C. or more, and preferably 800° C. or more and 1400° C. or less.

First claim

What is claimed is:

1. A method of producing hematite for ironmaking comprising:
mixing sulfuric acid and nickel oxide ore to form a slurry;
heating the slurry in a pressure vessel at a temperature of 240° C. to 250° C. wherein nickel is leached from the ore, thereby forming a nickel containing leachate slurry;
adding a neutralizer to the leachate slurry thereby neutralizing any sulfuric acid and forming a neutralized leachate slurry, wherein a reaction of the neutralizer and the sulfuric acid yields a calcium sulfate; and then
separating the neutralized leachate slurry into a leach residue and a leachate, where the leach residue includes iron oxide and calcium sulfate, and where the leachate includes nickel; and then
heating the leach residue that includes iron oxide and calcium sulfate to 600° C. or more and thereby providing hematite having a sulfur grade of less than 1%.

2. The method of claim 1 , wherein the leach residue is heated to a temperature of 800° C. to 1400° C.

3. The method of claim 2 , wherein the hematite has a sulfur grade of 0.8% to 0.1%.

4. The method of claim 2 further comprising heating the leach residue in an oxidizing atmosphere and removing sulfur from the leach residue as sulfur dioxide.

5. The method of claim 1 , wherein the neutralizer is a limestone or slaked lime.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Sasaki Hideki
• Mitsui Hiroyuki
• KAN Yasumasa

Classifications

• C01P2006/80

  Compositional purity · CPC title

• C22B3/22

  by physical processes, e.g. by filtration, by magnetic means {, or by thermal decomposition} (treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title

• C22B23/043

  Sulfurated acids or salts thereof · CPC title

• C01G49/06 Primary

  Ferric oxide [Fe2O3] · CPC title

• Y02P10/212

  Cross-Sectional Technologies · mapped topic