Wet smelting method for nickel oxide ore

Patent metadata

Field	Value
Publication number	US-2018037972-A1
Application number	US-201515552307-A
Country	US
Kind code	A1
Filing date	Dec 8, 2015
Priority date	Feb 24, 2015
Publication date	Feb 8, 2018
Grant date	—

Abstract

A wet smelting method for nickel oxide ores from which nickel, cobalt, etc. are recovered is provided with which it is possible to reduce the consumption of an acid in leaching, such as sulfuric acid, and to recover valuable metals. The method comprises: step (A) in which nickel oxide ores as a raw material are separated into a limonite-type ore having a low magnesium content and a saprolite-type ore having a high magnesium content; step (B) in which the saprolite-type ore is subjected to normal-pressure leaching under given standardized leaching conditions using the pressure leachate obtained by pressure leaching in step (C); and step (C) in which the limonite-type ore obtained in step (A) is mixed with the normal-pressure leaching residue obtained in step (B) and the mixture is reacted with sulfuric acid in an acidic atmosphere having a high temperature and a high pressure, thereby conducting pressure leaching.

First claim

1 . A wet smelting method for nickel oxide ore by which valuable metals such as nickel and cobalt are recovered from the nickel oxide ore, the method comprising:
a step (A) of separating the nickel oxide ore into a limonite-type ore having a low magnesium grade with a magnesium grade of 2% by weight or less and a saprolite-type ore having a high magnesium grade with a magnesium grade of more than 2% by weight; a step (B) of normal-pressure leaching the saprolite-type ore obtained in the step (A) by adding a pressure leachate which is obtained by pressure leaching in a step (C) described below and in which the concentration of sulfuric acid is adjusted such that the value, which is obtained by dividing the total value of the concentration of free acid contained in the pressure leachate and the concentration of iron ions calculated on the assumption that the existence form is trivalent by the grade of magnesium contained in the saprolite-type ore, becomes 1.5 mol/mol equivalent or less, to obtain a normal-pressure leachate and a normal-pressure leaching residue; and a step (C) of performing pressure leaching by mixing the limonite-type ore obtained in the step (A) and the normal-pressure leaching residue obtained in the step (B) and then reacting the resultant mixture with sulfuric acid in an acidic atmosphere under high temperature and high pressure, to obtain a pressure leachate.

Assignees

• Sumitomo Metal Mining Co

Inventors

• Shouji Hirofumi
• Kudo Keiji
• Ozaki Yoshitomo
• Kobayashi Hiroshi
• Asano Satoshi

Classifications

• C22B1/00 Primary

  Preliminary treatment of ores or scrap · CPC title

• C22B23/043

  Sulfurated acids or salts thereof · CPC title

• C22B3/08

  Sulfuric acid {, other sulfurated acids or salts thereof} · CPC title

• C22B23/005 Primary

  Preliminary treatment of ores, e.g. by roasting or by the Krupp-Renn process · CPC title

• Y02P10/20

  Recycling · CPC title