A method and system for leaching cobalt with SO2

Abstract

The present invention provides a method and a system for leaching cobalt with SO2. The method is to introduce SO2 gas simultaneously through three paths. The first path is to introduce SO2 gas into a pressurized adsorption tank, the second path is to introduce SO2 gas into a primary adsorption tower, and the third path is to introduce SO2 gas into a leaching tank. By using the reaction of SO2 gas with water to generate H2SO3, and then using H2SO3 to reduce Fe 3+ ions to Fe 2+ ions, and further using Fe 2+ ions to leach cobalt; the system includes a pressurized adsorption tank, a primary adsorption tower, a mixing tank and a leaching tank. The method and system for leaching cobalt with SO2 provided by the present invention introduce SO2 gas simultaneously through three paths, which can increase the utilization rate of SO2 gas by more than 15%. At the same time, a large amount of Fe 3+ in the raffinate is reduced to Fe 2+ , increasing the cobalt leaching rate by more than 3%, and at the same time avoiding environmental pollution caused by the escape of SO2 gas.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrometallurgy, and particularly to a method and a system for leaching cobalt with SO2. Background Art

[0002] The hydrometallurgical process of leaching - extraction - electrowinning - impurity removal - cobalt precipitation is a conventional process for treating copper oxide cobalt ore. Cobalt in the oxidized ore generally exists in the form of hydrocobaltite (CoOOH), and the Co in it 3+ needs to be leached with sulfuric acid under a reducing environment. Reducing agents such as SO2, Na2SO3, and FeSO4 can be used. In industrial production, SO2 gas is often used as a reducing agent for cobalt leaching.

[0003] Currently, the conventional process with the intervention of SO2 gas is to directly introduce SO2 gas into the leaching tank through an inlet pipe. This intervention technology has the following disadvantages:

[0004] (1) SO2 gas cannot be fully dissolved in the pulp, and the utilization rate is very low, resulting in high production costs;

[0005] (2) The reaction between SO2 gas and minerals is a gas - solid reaction. Actually, it is an indirect reduction reaction in which SO2 dissolves in water to form H2SO3, and the reaction efficiency is low, affecting the cobalt leaching effect;

[0006] (3) SO2 gas is likely to escape from the leaching tank, causing environmental pollution, endangering the safety of operators, and corroding the surrounding steel structures.

[0007] Therefore, it is urgent to research and develop a new cobalt leaching method and system. Summary of the Invention

[0008] To solve the above - mentioned technical problems, in the first aspect of the present invention, a method for leaching cobalt with SO2 is provided. The SO2 gas intervenes simultaneously through three paths:

[0009] The steps for leaching cobalt in the first path are as follows:

[0010] S1: Introduce SO2 gas and water into a pressurized adsorption tank to make the SO2 gas react with water to generate an H2SO3 solution;

[0011] S2: Introduce the raffinate and the H2SO3 solution obtained in step S1 into a mixing tank to make the H2SO3 solution react with the Fe 3 + ions in the raffinate, reduce the Fe 3+ ions to Fe 2+ ions, and obtain a raffinate rich in Fe 2+ ;

[0012] S3: Introduce the raffinate rich in Fe obtained in step S2 2+The raffinate is introduced into the leaching tank, and Fe is used 2+ to leach cobalt;

[0013] The steps for leaching cobalt in the second path are as follows:

[0014] Introduce SO2 gas and the raffinate into the primary adsorption tower, so that the SO2 gas reacts with the water in the raffinate to generate an H2SO3 solution. The H2SO3 solution then reacts with the Fe 3+ ions, reducing the Fe 3+ ions to Fe 2+ ions, obtaining the raffinate after SO2 reduction;

[0015] S2: Introduce the raffinate after SO2 reduction obtained in step S1 into the mixing tank, and repeat steps S2 and S3 of the first path;

[0016] The steps for leaching cobalt in the third path are as follows:

[0017] Introduce SO2 gas into the leaching tank, so that the SO2 gas reacts with the water in the pulp to generate an H2SO3 solution. The H2SO3 solution then reacts with the Fe 3+ ions, reducing the Fe 3+ ions to Fe 2+ ions, and use Fe 2+ to leach cobalt.

[0018] Furthermore, in order to reduce the environmental pollution caused by the escape of SO2 gas and to improve the utilization rate of SO2 gas, the SO2 gas escaping from the primary adsorption tower and the leaching tank is introduced into the packed adsorption tower. At the same time, the raffinate is introduced into the packed adsorption tower, so that the SO2 gas reacts with the water in the raffinate to generate an H2SO3 solution. The H2SO3 solution then reacts with the Fe 3+ ions, reducing the Fe 3+ ions to Fe 2+ ions, obtaining the raffinate after SO2 reduction, and then introducing the raffinate after SO2 reduction into the mixing tank.

[0019] Furthermore, the SO2 gas escaping from the primary adsorption tower and the leaching tank can also be collected and then introduced back into the pressure adsorption tank.

[0020] Among them, the SO2 gas is introduced from the bottom of the pressure adsorption tank, the primary adsorption tower and the leaching tank respectively, the raffinate is introduced from the top of the primary adsorption tower and the mixing tank respectively, and the water is introduced from the top of the pressure adsorption tank.

[0021] Among them, the pressure in the pressure adsorption tank is 350 - 450 kPa.

[0022] Preferably, the pressure of the pressure swing adsorption tank is 360 kPa, 370 kPa, 380 kPa, 390 kPa, 400 kPa, 410 kPa, 420 kPa, 430 kPa, 440 kPa.

[0023] Among them, in the pressure swing adsorption tank, the mass ratio of SO2 gas to water is 0.15 - 0.3:1.

[0024] Preferably, the mass ratio of SO2 gas to water is 0.16:1, 0.17:1, 0.18:1, 0.19:1, 0.20:1, 0.21:1, 0.22:1, 0.23:1, 0.24:1, 0.25:1, 0.26:1, 0.27:1, 0.28:1, 0.29:1.

[0025] In the second aspect of the present invention, a system for leaching cobalt with SO2 is provided. The system includes a pressure swing adsorption tank, a primary adsorption tower, a packed adsorption tower, a mixing tank, and a leaching tank;

[0026] The pressure swing adsorption tank, the primary adsorption tower, and the leaching tank are respectively connected to an SO2 gas inlet pipe. The primary adsorption tower, the packed adsorption tower, and the mixing tank are respectively connected to a raffinate inlet pipe. The pressure swing adsorption tank is connected to a water inlet pipe;

[0027] The primary adsorption tower and the packed adsorption tower are respectively connected to the mixing tank through liquid pipelines. The pressure swing adsorption tank, the mixing tank, and the leaching tank are sequentially connected through liquid pipelines. The primary adsorption tower and the leaching tank are respectively connected to the packed adsorption tower through gas pipelines.

[0028] Among them, the SO2 gas inlet pipe is respectively connected to the bottoms of the pressure swing adsorption tank, the primary adsorption tower, and the leaching tank; the raffinate inlet pipe is respectively connected to the tops of the primary adsorption tower, the packed adsorption tower, and the mixing tank; the water inlet pipe is connected to the top of the pressure swing adsorption tank; the gas pipeline connects the top of the primary adsorption tower to the bottom of the packed adsorption tower, and the gas pipeline connects the top of the leaching tank to the bottom of the packed adsorption tower.

[0029] In the third aspect of the present invention, another system for leaching cobalt with SO2 is provided. The system includes a pressure swing adsorption tank, a primary adsorption tower, a mixing tank, and a leaching tank;

[0030] The pressure swing adsorption tank, the primary adsorption tower, and the leaching tank are respectively connected to an SO2 gas inlet pipe. The primary adsorption tower and the mixing tank are respectively connected to a raffinate inlet pipe. The pressure swing adsorption tank is connected to a water inlet pipe;

[0031] The primary adsorption tower is connected to the mixing tank through a liquid pipeline. The pressurized adsorption tank, the mixing tank, and the leaching tank are sequentially connected through a liquid pipeline. The primary adsorption tower and the leaching tank are respectively connected to the pressurized adsorption tank through a gas pipeline.

[0032] Among them, the SO2 gas inlet pipe is respectively connected to the bottoms of the pressurized adsorption tank, the primary adsorption tower, and the leaching tank; the raffinate inlet pipe is respectively connected to the tops of the primary adsorption tower and the mixing tank; the water inlet pipe is connected to the top of the pressurized adsorption tank; the gas pipeline connects the top of the primary adsorption tower to the bottom of the pressurized adsorption tank, and the gas pipeline connects the top of the leaching tank to the bottom of the pressurized adsorption tank.

[0033] Advantages of the present invention:

[0034] The method and system for leaching cobalt with SO2 provided by the present invention have the following advantages:

[0035] The SO2 gas is introduced through three paths. The first path is to introduce the SO2 gas into the pressurized adsorption tank, so that the SO2 gas reacts with water to generate an H2SO3 solution, and then the H2SO3 solution reacts with the Fe 3+ ions in the raffinate to reduce the Fe 3+ ions to Fe 2+ ions, obtaining a raffinate rich in Fe 2+ , and then introducing the raffinate rich in Fe 2+ into the leaching tank to leach cobalt with Fe 2+ ; the second path is to introduce the SO2 gas into the primary adsorption tower, so that the SO2 gas reacts with the Fe 3+ ions in the raffinate to reduce part of the Fe 3+ ions to Fe 2+ ions, obtaining a raffinate after SO2 reduction, and then reacting the H2SO3 solution with the unreduced Fe 3+ ions in the raffinate after SO2 reduction to reduce the Fe 3+ ions to Fe 2+ ions, obtaining a raffinate rich in Fe 2+ ; the third path is to directly introduce the SO2 gas into the leaching tank, so that the SO2 gas reacts with the Fe 3+ ions in the pulp to reduce the Fe 3+ ions to Fe 2+ ions and leach cobalt with Fe 2+ . Using the method and system for leaching cobalt with SO2 provided by the present invention, the utilization rate of the SO2 gas can be increased by more than 15%, and at the same time, a large amount of Fe 3+ in the raffinate can be reduced to Fe 2+, which increases the cobalt leaching rate by more than 3%.

[0036] Compared with the prior art, in the present invention, by introducing SO2 gas into the pressure adsorption tank and the primary adsorption tower, the Fe 3+ ions are reduced to Fe 2+ ions. On the premise of improving the utilization rate of SO2 gas and the cobalt leaching rate, the escape of SO2 gas is also reduced. The SO2 gas escaping from the primary adsorption tower and the leaching tank is introduced into the packed adsorption tower or the pressure adsorption tank, further improving the utilization rate of SO2 gas and avoiding environmental pollution caused by the direct emission of SO2 gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0038] Figure 1 is a schematic diagram of the SO2 cobalt leaching system provided in Embodiment 1 of the present invention;

[0039] Figure 2 is a schematic diagram of the SO2 cobalt leaching system provided in Embodiment 2 of the present invention;

[0040] In the figure: 1 - pressure adsorption tank, 2 - primary adsorption tower, 3 - packed adsorption tower, 4 - mixing tank, 5 - leaching tank, 6 - SO2 gas inlet pipe, 7 - raffinate inlet pipe, 8 - water inlet pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The following are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

[0042] Embodiment 1

[0043] The present invention provides a method for leaching cobalt with SO2, and the SO2 gas intervenes simultaneously through three paths:

[0044] The steps for leaching cobalt in the first path are as follows:

[0045] S1: Introduce SO2 gas and water into the pressure adsorption tank 1 to make the SO2 gas react with water to generate H2SO3 solution. The reaction process is as follows:

[0046] SO2 + H2O → H2SO3;

[0047] S2: Introduce the raffinate and the H2SO3 solution obtained in step S1 into the mixing tank 4, and make the H2SO3 solution react with the Fe 3+ ions in the raffinate to reduce the Fe 3+ ions to Fe 2+ ions, obtaining a raffinate rich in Fe 2+ . The reaction process is as follows:

[0048] Fe2(SO4)3 + H2SO3 → FeSO4 + H2SO4;

[0049] S3: Introduce the raffinate rich in Fe 2+ obtained in step S2 into the leaching tank 5, and leach cobalt using Fe 2+ . The reaction process is as follows:

[0050] CoOOH + FeSO4 + H2SO4 → CoSO4 + Fe 2( (SO4)3 + H2O;

[0051] The steps for leaching cobalt in the second path are:

[0052] S1: Introduce SO2 gas and the raffinate into the primary adsorption tower 2, and make the SO2 gas react with the water in the raffinate to generate an H2SO3 solution. The H2SO3 solution then reacts with the Fe 3+ ions in the raffinate to reduce the Fe 3+ ions to Fe 2+ ions, obtaining the raffinate after SO2 reduction. The reaction process is as follows:

[0053] SO2 + H2O → H2SO3

[0054] Fe2(SO4)3 + H2SO3 → FeSO4 + H2SO4;

[0055] S2: Introduce the raffinate after SO2 reduction obtained in step S1 into the mixing tank 4, and repeat steps S2 and S3 of the first path;

[0056] The steps for leaching cobalt in the third path are:

[0057] S1: Introduce SO2 gas into the leaching tank 5, and make the SO2 gas react with the water in the pulp to generate an H2SO3 solution. The H2SO3 solution then reacts with the Fe 3+ ions in the pulp to reduce the Fe 3+ ions to Fe 2+ ions, and leach cobalt using Fe 2+ .

[0058] In this embodiment, the SO2 gas escaping from the primary adsorption tower 2 and the leaching tank 5 is introduced into the packed adsorption tower 3, and at the same time, the raffinate is introduced into the packed adsorption tower 3, so that the SO2 gas reacts with the water in the raffinate to generate an H2SO3 solution, and the H2SO3 solution then reacts with the Fe 3+ ions in the raffinate, and the Fe 3+ ions are reduced to Fe 2+ ions to obtain the raffinate after SO2 reduction, and then the raffinate after SO2 reduction is introduced into the mixing tank 4.

[0059] The method for leaching cobalt with SO2 provided in Example 1 is realized through the following system, as Figure 1 shown. The system includes a pressure adsorption tank 1, a primary adsorption tower 2, a packed adsorption tower 3, a mixing tank 4 and a leaching tank 5; the pressure adsorption tank 1, the primary adsorption tower 2 and the leaching tank 5 are respectively connected to an SO2 gas inlet pipe 6, the primary adsorption tower 2, the packed adsorption tower 3 and the mixing tank 4 are respectively connected to a raffinate inlet pipe 7, and the pressure adsorption tank 1 is connected to a water inlet pipe 8; the primary adsorption tower 2 and the packed adsorption tower 3 are respectively connected to the mixing tank 4 through liquid pipelines, the pressure adsorption tank 1, the mixing tank 4 and the leaching tank 5 are sequentially connected through liquid pipelines, and the primary adsorption tower 2 and the leaching tank 5 are respectively connected to the packed adsorption tower 3 through gas pipelines.

[0060] The SO2 gas inlet pipe 6 is respectively connected to the bottoms of the pressure adsorption tank 1, the primary adsorption tower 2 and the leaching tank 5; the raffinate inlet pipe 7 is respectively connected to the tops of the primary adsorption tower 2, the packed adsorption tower 3 and the mixing tank 4; the water inlet pipe 8 is connected to the top of the pressure adsorption tank 1; the gas pipeline connects the top of the primary adsorption tower 2 to the bottom of the packed adsorption tower 3, and the gas pipeline connects the top of the leaching tank 5 to the bottom of the packed adsorption tower 3.

[0061] Taking a copper-cobalt oxide ore project as an example in Example 1, 70 t / d of SO2 gas is mixed and reacted with 319 t / d of process water in the pressure adsorption tank 1 at 400 kPa to generate an H2SO3 solution, and the mass ratio of SO2 gas to water is 0.22:1; then the H2SO3 solution is led into the mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ in the raffinate is reduced to Fe 2+ to obtain a raffinate rich in Fe 2+ , and the Fe 2+ content therein is increased from 0.29 g / L before the reaction to 0.54 g / L. Then, the raffinate rich in Fe 2+The raffinate is introduced into the cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 16.4%, and the cobalt leaching rate is increased by 3.4%.

[0062] Example 2

[0063] The present invention provides a method for leaching cobalt with SO2. The SO2 gas intervenes simultaneously through three paths:

[0064] The steps for leaching cobalt in the first path are as follows:

[0065] S1: Introduce SO2 gas and water into the pressure adsorption tank 1 to make the SO2 gas react with water to generate H2SO3 solution. The reaction process is as follows:

[0066] SO2 + H2O → H2SO3;

[0067] S2: Introduce the raffinate and the H2SO3 solution obtained in step S1 into the mixing tank 4 to make the H2SO3 solution react with the Fe 3+ ions in the raffinate, and reduce the Fe 3+ ions to Fe 2+ ions to obtain a raffinate rich in Fe 2+ The reaction process is as follows:

[0068] Fe2(SO4)3 + H2SO3 → FeSO4 + H2SO4;

[0069] S3: Introduce the raffinate rich in Fe 2+ obtained in step S2 into the leaching tank 5 to leach cobalt using Fe 2+ The reaction process is as follows:

[0070] CoOOH + FeSO4 + H2SO4 → CoSO4 + Fe 2( SO4)3 + H2O;

[0071] The steps for leaching cobalt in the second path are as follows:

[0072] S1: Introduce SO2 gas and the raffinate into the primary adsorption tower 2 to make the SO2 gas react with the water in the raffinate to generate H2SO3 solution. The H2SO3 solution then reacts with the Fe 3+ ions in the raffinate, and reduce the Fe 3+ ions to Fe 2+ ions to obtain the raffinate after SO2 reduction. The reaction process is as follows:

[0073] SO2 + H2O → H2SO3

[0074] Fe2(SO4)3 + H2SO3 → FeSO4 + H2SO4;

[0075] S2: Introduce the reduced raffinate obtained in step S1 into the mixing tank 4, and repeat steps S2 and S3 of the first path;

[0076] The steps for leaching cobalt in the third path are as follows:

[0077] S1: Introduce SO2 gas into the leaching tank 5, react the SO2 gas with the water in the pulp to generate an H2SO3 solution, and the H2SO3 solution then reacts with the Fe 3+ ions in the pulp to 3+ reduce the Fe 2+ ions to Fe 2+ ions, and use Fe

[0078] In this embodiment, introduce the SO2 gas escaping from the primary adsorption tower 2 and the leaching tank 5 into the pressure adsorption tank 1. The specific operation steps are as described in the method provided by the first path and will not be elaborated here.

[0079] The method for leaching cobalt with SO2 provided in Example 2 is realized through the following system. As Figure 2 shown, the system includes a pressure adsorption tank 1, a primary adsorption tower 2, a mixing tank 4, and a leaching tank 5; the pressure adsorption tank 1, the primary adsorption tower 2, and the leaching tank 5 are respectively connected to an SO2 gas inlet pipe 6, the primary adsorption tower 2 and the mixing tank 4 are respectively connected to a raffinate inlet pipe 7, and the pressure adsorption tank 1 is connected to a water inlet pipe 8; the primary adsorption tower 2 and the mixing tank 4 are connected through a liquid pipeline, the pressure adsorption tank 1, the mixing tank 4, and the leaching tank 5 are successively connected through liquid pipelines, and the primary adsorption tower 2 and the leaching tank 5 are respectively connected to the pressure adsorption tank 1 through gas pipelines.

[0080] The SO2 gas inlet pipe 6 is respectively connected to the bottoms of the pressure adsorption tank 1, the primary adsorption tower 2, and the leaching tank 5; the raffinate inlet pipe 7 is respectively connected to the tops of the primary adsorption tower 2 and the mixing tank 4; the water inlet pipe 8 is connected to the top of the pressure adsorption tank 1; the gas pipeline connects the top of the primary adsorption tower 2 to the bottom of the pressure adsorption tank 1, and the gas pipeline connects the top of the leaching tank 5 to the bottom of the pressure adsorption tank 1.

[0081] Taking a copper-cobalt oxide ore project as an example in Example 2, 80 t / d of SO2 gas is mixed and reacted with 319 t / d of process water in the pressure adsorption tank 1 at 380 kPa to generate an H2SO3 solution, and the mass ratio of SO2 gas to water is 0.25:1; then the H2SO3 solution is led into the mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ in the raffinate is reduced to Fe 2+, a raffinate rich in Fe is obtained 2+ , and the Fe 2+ content increases from 0.29 g / L before the reaction to 0.56 g / L. Then, the raffinate rich in Fe 2+ is introduced into the cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 16.1%, and the cobalt leaching rate is increased by 3.3%.

[0082] To verify the stability and effectiveness of the method and system for leaching cobalt with SO2 provided by the present invention, the following will take Example 1 as a reference, control other process parameters unchanged, and set a group of comparative tests by adjusting the inlet gas volume of SO2 gas:

[0083] Comparative Test 1

[0084] Taking a copper-cobalt oxide ore project as an example, 60 t / d of SO2 gas is mixed and reacted with 319 t / d of process water in the pressurized adsorption tank 1 at 400 kPa to generate an H2SO3 solution. The mass ratio of SO2 gas to water is 0.19:1. Then, the H2SO3 solution is introduced into the mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ in the raffinate is reduced to Fe 2+ , obtaining a raffinate rich in Fe 2+ , and the Fe 2+ content increases from 0.29 g / L before the reaction to 0.48 g / L. Then, the raffinate after SO2 reduction is added to the cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 15.2%, and the cobalt leaching rate is increased by 3.1%.

[0085] Comparative Test 2

[0086] Taking a copper-cobalt oxide ore project as an example, 65 t / d of SO2 gas is mixed and reacted with 319 t / d of process water in the pressurized adsorption tank 1 at 400 kPa to generate an H2SO3 solution. The mass ratio of SO2 gas to water is 0.20:1. Then, the H2SO3 solution is introduced into the mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ in the raffinate is reduced to Fe 2+ , obtaining a raffinate rich in Fe 2+ , and the Fe 2+ content increases from 0.29 g / L before the reaction to 0.52 g / L. Then, the raffinate after SO2 reduction is added to the cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 15.3%, and the cobalt leaching rate is increased by 3.3%.

[0087] Comparative Test 3

[0088] Taking a copper-cobalt oxide ore project as an example, 80 t / d of SO2 gas is mixed and reacted with 319 t / d of process water in a pressurized adsorption tank 1 at 400 kPa to generate an H2SO3 solution, and the mass ratio of SO2 gas to water is 0.25:1; then the H2SO3 solution is led into a mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ is reduced to Fe 2+ , obtaining a raffinate rich in Fe 2+ , and the content of Fe 2+ in it is increased from 0.29 g / L before the reaction to 0.54 g / L. Then, the raffinate after SO2 reduction is added to a cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 15.9%, and the cobalt leaching rate is increased by 3.3%.

[0089] Comparative experiment 4

[0090] Taking a copper-cobalt oxide ore project as an example, 86 t / d of SO2 gas is mixed and reacted with 319 t / d of process water in a pressurized adsorption tank 1 at 400 kPa to generate an H2SO3 solution, and the mass ratio of SO2 gas to water is 0.27:1; then the H2SO3 solution is led into a mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ is reduced to Fe 2+ , obtaining a raffinate rich in Fe 2+ , and the content of Fe 2+ in it is increased from 0.29 g / L before the reaction to 0.59 g / L. Then, the raffinate after SO2 reduction is added to a cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 16.3%, and the cobalt leaching rate is increased by 3.3%.

[0091] Comparative experiment 5

[0092] Taking a copper-cobalt oxide ore project as an example, 90 t / d of SO2 gas is mixed and reacted with 319 t / d of process water in a pressurized adsorption tank 1 at 400 kPa to generate an H2SO3 solution, and the mass ratio of SO2 gas to water is 0.28:1; then the H2SO3 solution is led into a mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ is reduced to Fe 2+ , obtaining a raffinate after SO2 reduction, and the content of Fe 2+ in it is increased from 0.29 g / L before the reaction to 0.61 g / L. Then, the raffinate after SO2 reduction is added to a cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 16.4%, and the cobalt leaching rate is increased by 3.4%.

[0093] It can be seen from Example 1 and Comparative Tests 1-5 that when the mass ratio of SO2 gas to water is between 0.15 and 0.3:1, using the method and system provided in Example 2, the utilization rate of SO2 gas can be increased by more than 15%, and the cobalt leaching rate can be increased by more than 3%.

[0094] To verify the method and system for leaching cobalt with SO2 provided by the present invention, the effects of introducing SO2 gas through three paths and two paths were compared, and comparative examples were also set up in the present invention.

[0095] Comparative Example

[0096] The present invention provides a method for leaching cobalt with SO2, and SO2 gas intervenes simultaneously through two paths:

[0097] The steps for leaching cobalt in the first path are as follows:

[0098] S1: Introduce SO2 gas and water into the pressure adsorption tank 1 to make the SO2 gas react with water to generate an H2SO3 solution;

[0099] S2: Introduce the raffinate and the H2SO3 solution obtained in step S1 into the mixing tank 4 to make the H2SO3 solution react with the Fe 3+ ions in the raffinate, and reduce the Fe 3+ ions to Fe 2+ ions to obtain a raffinate rich in Fe 2+ ;

[0100] S3: Introduce the raffinate rich in Fe 2+ obtained in step S2 into the leaching tank 5, and leach cobalt using Fe 2+ ;

[0101] The steps for leaching cobalt in the second path are as follows:

[0102] Introduce SO2 gas into the leaching tank 5 to make the SO2 gas react with the water in the pulp to generate an H2SO3 solution, and the H2SO3 solution then reacts with the Fe 3+ ions in the pulp, reduce the Fe 3+ ions to Fe 2+ ions, and leach cobalt using Fe 2+ ;

[0103] Taking a copper-cobalt oxide ore project as an example, in the comparative example, 70 t / d of SO2 gas was mixed and reacted with 319 t / d of process water in the pressure adsorption tank 1 at 400 kPa to generate an H2SO3 solution, and the mass ratio of SO2 gas to water was 0.22:1; then the H2SO3 solution was introduced into the mixing tank 4 to be fully mixed with the raffinate, and the Fe 3+ in the raffinate was reduced to Fe2+ , the raffinate after SO2 reduction is obtained, in which the Fe 2+ content increases from 0.29 g / L before the reaction to 0.47 g / L. Then, the raffinate after SO2 reduction is added to the cobalt leaching tank for cobalt reduction leaching. The utilization rate of SO2 gas is increased by 12.8%, and the cobalt leaching rate is increased by 2.6%.

[0104] It can be seen from the comparative examples that when SO2 gas is introduced through two ways, the utilization rate of SO2 gas and the cobalt leaching rate both decrease significantly. When SO2 gas is introduced through the three ways provided by the present invention, the utilization rate of SO2 gas can be increased by more than 15%, and the cobalt leaching rate can be increased by more than 3%.

[0105] The above embodiments only represent the specific implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for leaching cobalt with SO2, characterized in that, SO2 gas intervenes simultaneously through three paths: The steps for leaching cobalt in the first path are as follows: S1: Introduce SO2 gas and water into the pressure adsorption tank (1) to cause the SO2 gas and water to react and generate an H2SO3 solution; S2: Introduce the raffinate and the H2SO3 solution obtained in step S1 into the mixing tank (4) so that the H2SO3 solution reacts with the Fe 3+ ions in the raffinate, reducing the Fe 3+ ions to Fe 2+ ions and obtaining a raffinate rich in Fe 2+ ; S3: Introduce the raffinate rich in Fe obtained in step S2 2+ into the leaching tank (5) and leach cobalt using Fe 2+ ; The steps for leaching cobalt in the second path are as follows: S1: Introduce SO2 gas and the raffinate into the primary adsorption tower (2) to allow the water in the SO2 gas and the raffinate to react to form an H2SO3 solution, and then the H2SO3 solution reacts with the Fe 3+ ions in the raffinate to reduce the Fe 3+ ions to Fe 2+ ions, obtaining the raffinate after SO2 reduction; S2: Introduce the SO2-reduced raffinate obtained in step S1 into the mixing tank (4), and repeat steps S2 and S3 of the first path; The steps for leaching cobalt in the third path are as follows: Introduce SO2 gas into the leaching tank (5) so that the SO2 gas reacts with the water in the pulp to form an H2SO3 solution, and the H2SO3 solution then reacts with the Fe 3+ ions, reducing the Fe 3+ ions to Fe 2+ ions, and using Fe 2+ to leach cobalt.

2. The method for leaching cobalt with SO2 according to claim 1, characterized in that: Introduce the SO2 gas escaping from the primary adsorption tower (2) and the leaching tank (5) into the packed adsorption tower (3), and at the same time introduce the raffinate into the packed adsorption tower (3) so that the SO2 gas reacts with the water in the raffinate to generate an H2SO3 solution, and the H2SO3 solution then reacts with the Fe 3+ ions in the raffinate, reducing the Fe 3+ ions to Fe 2+ ions to obtain the raffinate after SO2 reduction, and then introduce the raffinate after SO2 reduction into the mixing tank (4).

3. A method for leaching cobalt with SO2 according to claim 1, characterized in that: Introduce the SO2 gas escaping from the primary adsorption tower (2) and the leaching tank (5) into the pressure adsorption tank (1).

4. A method for leaching cobalt with SO2 according to claim 1, characterized in that: The SO2 gas is introduced from the bottom of the pressure adsorption tank (1), the primary adsorption tower (2), and the leaching tank (5) respectively. The raffinate is introduced from the top of the primary adsorption tower (2) and the mixing tank (4) respectively. The water is introduced from the top of the pressure adsorption tank (1).

5. A method for leaching cobalt with SO2 according to any one of claims 1 to 4, characterized in that: The pressure in the pressure adsorption tank (1) is 350 - 450 kPa.

6. A method for leaching cobalt with SO2 according to any one of claims 1 to 4, characterized in that: In the pressure adsorption tank (1), the mass ratio of SO2 gas to water is 0.15 - 0.3:

1.

7. A system for leaching cobalt with SO2, characterized in that: The system includes a pressure adsorption tank (1), a primary adsorption tower (2), a packed adsorption tower (3), a mixing tank (4), and a leaching tank (5); The pressure adsorption tank (1), the primary adsorption tower (2), and the leaching tank (5) are respectively connected to the SO2 gas inlet pipe (6). The primary adsorption tower (2), the packed adsorption tower (3), and the mixing tank (4) are respectively connected to the raffinate inlet pipe (7). The pressure adsorption tank (1) is connected to the water inlet pipe (8); The primary adsorption tower (2) and the packed adsorption tower (3) are respectively connected to the mixing tank (4) through liquid pipelines. The pressure adsorption tank (1), the mixing tank (4), and the leaching tank (5) are sequentially connected through liquid pipelines. The primary adsorption tower (2) and the leaching tank (5) are respectively connected to the packed adsorption tower (3) through gas pipelines.

8. A system for leaching cobalt with SO2 according to claim 7, characterized in that: The SO2 gas inlet pipe (6) is respectively connected to the bottoms of the pressure adsorption tank (1), the primary adsorption tower (2), and the leaching tank (5); the raffinate inlet pipe (7) is respectively connected to the tops of the primary adsorption tower (2), the packed adsorption tower (3), and the mixing tank (4); the water inlet pipe (8) is connected to the top of the pressure adsorption tank (1); the gas pipeline connects the top of the primary adsorption tower (2) to the bottom of the packed adsorption tower (3), and the gas pipeline connects the top of the leaching tank (5) to the bottom of the packed adsorption tower (3).

9. A system for leaching cobalt with SO2, characterized in that: The system includes a pressure adsorption tank (1), a primary adsorption tower (2), a mixing tank (4), and a leaching tank (5); The pressure adsorption tank (1), the primary adsorption tower (2), and the leaching tank (5) are respectively connected to the SO2 gas inlet pipe (6). The primary adsorption tower (2) and the mixing tank (4) are respectively connected to the raffinate inlet pipe (7). The pressure adsorption tank (1) is connected to the water inlet pipe (8); The primary adsorption tower (2) is connected to the mixing tank (4) through a liquid pipeline. The pressurized adsorption tank (1), the mixing tank (4), and the leaching tank (5) are connected in sequence through a liquid pipeline. The primary adsorption tower (2) and the leaching tank (5) are respectively connected to the pressurized adsorption tank (1) through a gas pipeline.

10. A system for leaching cobalt with SO2 according to claim 9, characterized in that: The SO2 gas inlet pipe (6) is respectively connected to the bottoms of the pressurized adsorption tank (1), the primary adsorption tower (2), and the leaching tank (5); the raffinate inlet pipe (7) is respectively connected to the tops of the primary adsorption tower (2) and the mixing tank (4); the water inlet pipe (8) is connected to the top of the pressurized adsorption tank (1); the gas pipeline connects the top of the primary adsorption tower (2) to the bottom of the pressurized adsorption tank (1), and the gas pipeline connects the top of the leaching tank (5) to the bottom of the pressurized adsorption tank (1).

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