EP2270241A1

EP2270241A1 - A method of extracting ni and/or co

Info

Publication number: EP2270241A1
Application number: EP09737668A
Authority: EP
Inventors: Nengdi Lu; Hong Ouyang; Fangchun Xiao; Yuanfa Cui
Original assignee: Jiangxi Rare Earth and Rare Metals Tungsten Group Holding Co Ltd
Current assignee: Jiangxi Rare Earth and Rare Metals Tungsten Group Holding Co Ltd
Priority date: 2008-04-30
Filing date: 2009-04-21
Publication date: 2011-01-05
Also published as: AU2009242827A1; CN101270417A; WO2009132558A1; EP2270241A4; CN101270417B; AU2009242827B2

Abstract

A method for extracting nickel and/or cobalt, comprising a process of heap leaching and a process of atmospheric warming, stirring and leaching, characterized in that the limonite-type ore is leached by atmospheric warming and stirring, while the serpentine-type ore is leached by heap leaching. According to the invention, different leaching processes are employed for the serpentine-type ore and the limonite-type ore in the laterite-nickel ore, respectively, the serpentine-type ore is leached by a process of heap leaching to obtain a faster leaching speed, and the limonite-type ore is leached by a process of atmospheric warming and stirring, thus the problems of extremely low heap leaching speed and long leaching period are avoided.

Description

FIELD OF THE PRESENT INVENTION

The present invention relates to a method for extracting nickel and/or cobalt, particularly to a method for extracting nickel and/or cobalt from a laterite-nickel ore, and in particular to a method for extracting nickel, cobalt, or both nickel and cobalt by separately collecting and processing laterite-nickel ores of the limonite-type and the serpentine-type (also called serpentite-type). It is related to a technology of hydrometallurgy.

PRIOR ART

According to prior art, the method for extracting nickel, cobalt, or both nickel and cobalt from a laterite-nickel ore comprises a process of heap leaching and a process of atmospheric warming, stirring and leaching for the laterite-nickel ore.
However, in the current process of heap leaching, the serpentine-type ore and the limonite-ore are mixed together for heap leaching, resulting in a slow permeation and a long leaching period.
Further, in the current process of atmospheric warming, stirring and leaching, the serpentine-type ore, which could have obtained a shorter leaching period by a heap leaching process, is mixed together with the limonite-type ore for warming, stirring and leaching, while the latter cannot obtain a shorter leaching period by a heap leaching process. As a result, the volume for processing becomes too much, so more equipments are needed with a high energy consumption.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of prior art, the object of the present invention is to provide a method for extracting nickel and/or cobalt, with a fast leaching speed, a short leaching period, and a brief technical process.
Another object of the present invention is to provide a method for extracting nickel and/or cobalt, with simple, less equipments and a lower cost.
Still another object of the present invention is to provide a method for extracting nickel and/or cobalt, with a lower energy consumption and a higher cost effectiveness.
Still another object of the present invention is to provide a method for extracting nickel and/or cobalt, with a high leaching rate for nickel.
Accordingly, the present invention provides a method for extracting nickel and/or cobalt, which comprises a process of heap leaching and a process of atmospheric warming, stirring and leaching, characterized in that, a limonite-type ore is leached by atmospheric stirring, while a serpentine-type ore is leached by heap leaching.
Preferably, both nickel and cobalt, as well as nickel or cobalt are extracted from a laterite-nickel ore.
Preferably, the process of the atmospheric stirring and leaching for the limonite-type ore comprises the following procedures:

controlling the grain size of the ore to be less than 1cm;
adding an ore leaching agent with a concentration of 20 to 30% in an ore/ore leaching agent ratio (W/V, Weight/Volumn) of 1.0:1.5 to 1.0:2.5, leaching at a temperature of 70 to 100°C under stirring for 48 to 4h; and
filtering the ore slurry leached out and washing the filter residue with water, the obtained leachate being used for preparing nickel and cobalt products.

Preferably, the process of the heap leaching for the serpentine-type ore comprises the following procedures:

controlling the grain size of the ore to be less than 3cm, the water content of the ore to be more than 20mass%, and a batch layer of 1 to 6m in thickness;
adding an ore leaching agent with a concentration of 5 to 15% and allowing it flow naturally from the top to the bottom for impregnation; and
adjusting the leachate collected such that the concentration of nickel ion in the leachate being 1.5 to 5g/L for preparing nickel and cobalt products, while the leachate less than 1.2g/L in nickel ion concentration being returned for ore leaching.

Preferably, in additional step E, the ore leaching agent with a concentration of 5 to 15% is added from the top of the leaching column, allowing it flow naturally from the top to the bottom for impregnation.
Preferably, the ore leaching agent is an aqueous solution containing sulfuric acid, hydrochloric acid, or their mixture.
Preferably, the nickel and cobalt products are prepared from the obtained leachate.
Preferably, the grain size of the ore is controlled by crushing the ore.
Preferably, the ore with a grain size larger than 1cm is crushed for controlling the grain size of the ore to be less than 1cm; a 20% solution of sulfuric acid is added in an ore/ore leaching agent ratio (W/V) of 1.0:2.3 for leaching at 80°C under stirring for 24h; the ore slurry leached out is filtered, water is added in a liquid-solid ratio of 3:1 to wash the filter residue, and the leachate is used for preparing nickel and cobalt products.
Preferably, the ore with a grain size larger than 3 cm is crushed for controlling the grain size of the ore to be less than 3cm, the water content of the ore to be 25%, and a batch layer of 5m in thickness; an aqueous solution of sulfuric acid as the ore leaching agent is prepared with a concentration of 10%, and the ore leaching agent is added from the top of the leaching column to allow for impregnation naturally; the leachate is collected by stages, high peak solutions of nickel and cobalt are concentrated during the early stage of the ore leaching, the leachate is adjusted such that the concentration of nickel ion in the leachate reaches up to 2g/L for preparing nickel and cobalt products, while the leachate less than 1.2g/L in nickel ion concentration is returned for ore leaching.
According to the invention, the serpentine-type ore in the laterite-nickel ore is collected and leached separately in order that a shorter leaching period and a higher leaching rate are obtained, while the remaining limonite-type ore is leached by atmospheric warming and stirring, thus getting a faster leaching speed as well as reducing the process volume by half or so.
According to the invention, different processes of leaching are employed respectively for the serpentine-type ore and the limonite-type ore in the laterite-nickel ore, a process of heap leaching is used for the serpentine-type ore to get a faster leaching speed, while the limonite-type ore is leached by a process of atmospheric warming and stirring to avoid the problems of very slow heap leaching and long leaching period.
Since the serpentine-type ore has a better leaching performance than the limonite-type ore, as opposed to the current process of mixing the above-mentioned two ores together for heap leaching or for stirring and leaching, in the present invention, the serpentine-type ore which is more suitable for heap leaching is leached by a process of heap leaching, thus obtaining both a short leaching period and a high leaching rate. While the limonite-type ore which is difficult to be leached is leached by a process of warming and stirring, thus obtaining both a faster leaching speed and a higher leaching rate. Accordingly, such a dual process achieves a better technical effect than the single process of heap leaching or the single process of warming, stirring and leaching does.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 is a flow diagram for preparing nickel and cobalt products from a limonite-type ore by a process of atmospheric stirring and leaching.
Figure 2 is a flow diagram for preparing nickel and cobalt products from a serpentine-type ore by a process of column leaching (simulated heap leaching).

BEST MODE OF CARRYING OUT THE PRESENT INVENTION

The inventors have found that, in the process of heap leaching, the serpentine-type ore has a shorter leaching period, while the limonite-type ore has a longer leaching period.
As shown in Figure 1, a process of atmospheric stirring and leaching to prepare nickel and cobalt products from limonite-type ore comprises the following steps: a step of ore preparation 11; a step of atmospheric stirring and leaching 12; and a step of solid/liquid separation 13, wherein carrying out the step 12 includes a step of applying an inorganic acid 111, the step of solid/liquid separation 13 produces a leachate 14 for preparing nickel and cobalt products as well as a leached residue 15.
According to one embodiment, the process of atmospheric stirring and leaching to prepare nickel and cobalt products from limonite-type ore comprises the following steps:

A. crushing the ore with a grain size larger than 1cm to control the grain size of the ore to be less than 1cm;
B. adding a 20% solution of sulfuric acid in an ore/ore leaching agent ratio (W/V) of 1.0:2.3, and leaching at 80°C under stirring for 24h;
C. filtering the ore slurry leached out and adding water in a liquid-solid ratio of 3:1 to wash the filter residue, the leachate being used for preparing nickel and cobalt products.

In this embodiment, the leaching rate for nickel was up to 82.37%, and the leachate containing nickel and cobalt could be processed according to prior art to obtain the nickel and cobalt products.
In other embodiments, the ore/ore leaching agent ratio (W/V) could be 1.0:1.5 to 1.0:2.5, the concentration of the ore leaching agent could be 20 to 30%, the temperature while stirring could be 70 to 100°C, the leaching time could be 48 to 4h, thus the objects of the present invention could also be achieved.
As shown in Figure 2, a process of column leaching (simulated heap leaching) to prepare nickel and cobalt products from serpentine-type ore comprises the following steps: a step of ore preparation 21; a step of column leaching (simulated heap leaching) 22; and a step of determining the density of the leachate 23, wherein carrying out the step of column leaching (simulated heap leaching) 22 includes a step of applying an inorganic acid 211, which produces a leachate 24 for preparing nickel and cobalt products as well as a leached residue 25.
According to one embodiment, the process of column leaching (simulated heap leaching) to prepare nickel and cobalt products from serpentine-type ore comprises the following steps:

A. crushing the ore with a grain size larger than 3 cm to control the grain size of the ore to be less than 3cm and the water content of the ore to be 25% or so;
B. having a batch layer of 5m in thickness;
C. preparing an aqueous solution of sulfuric acid as an ore leaching agent with a concentration of 10%, and adding the ore leaching agent from the top of the leaching column to allow for impregnation naturally;
D. collecting the leachate by stages, high peak solutions of nickel and cobalt being concentrated during the early stage of the ore leaching, adjusting the leachate such that the concentration of nickel ion in the leachate reaching up to 2g/L for preparing nickel and cobalt products, while the leachate less than 1.2g/L in nickel ion concentration being returned for ore leaching.

In this embodiment, after 38 days of leaching, the leaching rate for nickel was 84.9%. And the leachate containing nickel and cobalt could be processed according to prior art to obtain the nickel and cobalt products.
In other embodiments, the water content of the ore could be controlled to be more than 20%; the batch layer could be 1 to 6m in thickness, the concentration of the ore leaching agent could be 5 to 15%, the concentration of nickel ion in the leachate could be 1.5 to 5g/L, thus the objects of the present invention could also be achieved.
Particularly, in various embodiments, the ore leaching agent can be an aqueous solution containing sulfuric acid, hydrochloric acid, or their mixture.
It should be noted that, inspired by the spirit of the present invention, various modifications, variations and improvements in one way or another could be made by those skilled in the art through the disclosures above. However, these are also included within the scope of protection as claimed.

Claims

A method for extracting nickel and/or cobalt, comprising a process of heap leaching and a process of atmospheric warming, stirring and leaching, characterized in that, a limonite-type ore is leached by the process of atmospheric warming and stirring and leaching, while a serpentine-type ore is leached by the process of heap leaching.
The method according to claim 1, characterized in that both nickel and cobalt, as well as nickel or cobalt are extracted from a laterite-nickel ore.
The method according to claim 1, characterized in that the process of atmospheric warming, stirring and leaching for the limonite-type ore comprises the following procedures:
controlling the grain size of the ore to be less than 1cm;

adding an ore leaching agent with a concentration of 20 to 30% in an ore/ore leaching agent (W/V) ratio of 1.0:1.5 to 1.0:2,5, leaching at a temperature of 70 to 100°C under stirring for 48 to 4h; and

filtering the ore slurry leached out and washing the filter residue with water, the obtained leachate being used for preparing nickel and cobalt products.
The method according to claim 1, characterized in that the process of heap leaching for the serpentine-type ore comprises the following procedures:
controlling the grain size of the ore to be less than 3cm, and controlling the water content of the ore to be more than 20%;

having a batch layer of 1 to 6m in thickness;

adding an ore leaching agent with a concentration of 5 to 15% for impregnation;
and

adjusting the leachate collected such that the concentration of nickel ion in the leachate reaching up to 1.5 to 5g/L for preparing nickel and cobalt products, while the leachate less than 1.2g/L in nickel ion concentration being returned for ore leaching.
The method according to claim 4, characterized in that, in additional step E, an ore leaching agent with a concentration of 5 to 15% is added from the top of the leaching column, allowing it flow naturally from the top to the bottom for impregnation.
The method according to claim 3 or 4, characterized in that the ore leaching agent is an aqueous solution containing sulfuric acid, hydrochloric acid, or their mixture.
The method according to claim 3 or 4, characterized in that the nickel and cobalt products are prepared from the obtained leachate.
The method according to claim 3 or 4, characterized in that the grain size of the ore is controlled by crushing the ore.
The method according to claim 3, characterized in that,
crushing the ore with a grain size larger than 1cm to control the grain size of the ore to be less than 1cm;
adding a 20% solution of sulfuric acid in an ore/ore leaching agent ratio (W/V) of 1.0; 2.3, and leaching at 80°C under stirring for 24h;
filtering the ore slurry leached out and adding water in a liquid-solid ratio of 3:1 to wash the filter residue, the leachate being used for preparing nickel and cobalt products.
The method according to claim 4, characterized in that,
crushing the ore with a grain size larger than 3 cm to control the grain size of the ore to be less than 3cm, the water content of the ore to be 25%, and a batch layer of 5m in thickness;
preparing an aqueous solution of sulfuric acid as an ore leaching agent with a concentration of 10%, and adding the ore leaching agent from the top of the leaching column to allow for impregnation naturally;
collecting the leachate by stages, high peak solutions of nickel and cobalt being concentrated during the early stage of the ore leaching, adjusting the leachate such that the concentration of nickel ion in the leachate being up to 2g/L for preparing nickel and cobalt products, while the leachate less than 1.2g/L in nickel ion concentration being returned for ore leaching.